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QC 20120413

QC 20120330

QC 20120330

Features of light absorption are critical to optical aspects of water quality and in regulating the signal available for remote sensing Spectral characteristics and spatial patterns of light-absorbing components, and their relationships with optically active constituents, are documented for the Sturgeon River, Keweenaw Bay, and Lake Superior based on analyses of samples collected on two cruises (2006 and 2007, 20 sites). The absorption coefficient, a (m- I), is partitioned according to the additive components (ax) of colored dissolved organic matter (aCDOM), non-algal particles (aNAP), phytoplankton (aphi), and water itself (aw; known). The role of minerogenic particles and their iron content in regulating aNAP is evaluated based on paired measurements by an individual particle analysis technique (Peng et al.. 2009). through empirical analyses and Mie theory calculations of absorption by these particles (am). Spectral characteristics of aNAP and aphi were consistent with those reported for other case 2 (i .e., phytoplankton not dominant) systems. However, the slope values that describe aCDOM spectra for the bay and the lake were unusually low, suggesting an atypical composition for the lake's CDOM. The dominant absorbing component in the blue wavelengths was CDOM, representing greater than or equal to 75% of a at a wavelength of 440 nm at all sites in the 2006 survey. A general gradient in both aCDOM and aNAP extended from the Sturgeon River. through the bay, into eastern Lake Superior in that survey. Relationships between ax and optically active constituents were within the broad ranges reported for other case 2 systems. Minerogenic particles, related to their iron content, are demonstrated to be an important component of aNAP., Pub. in Jnl of Great Lakes Research, v36 p656-665, 2010.

Objective: Investigation of the predictability of finite element (FE) models regarding rupture risk assessment of abdominal aortic aneurysms (AAAs). Materials and materials: Peak wall stress (PWS) and peak wall rupture risk (PWRR) of ruptured (n = 20) and non-ruptured (n = 30) AAAs were predicted by four FE models of different complexities derived from computed tomography (CT) data. Two matching sub-groups of ruptured and non-ruptured aneurysms were used to investigate the usability of different FE models to discriminate amongst them. Results: All FE models exhibited a strong positive correlation between PWS and PWRR with the maximum diameter. FE models, which excluded the intra-luminal thrombus (ILT) failed to discriminate between ruptured and non-ruptured aneurysms. The predictability of all applied FE models was strengthened by including wall strength data, that is, computing the PWRR. The most sophisticated FE model applied in this study predicted PWS and PWRR 1.17 (p = 0.021) and 1.43 (p = 0.016) times higher in ruptured than diameter-matched non-ruptured aneurysms, respectively. Conclusions: PWRR reinforces PWS as a biomechanical rupture risk index. The ILT has a major impact on AAA biomechanics and rupture risk, and hence, needs to be considered in meaningful FE simulations. The applied FE models, however, could not explain rupture in all analysed aneurysms., QC 20101203

QC 20120418

Introduction Image modalities like Duplex Ultrasound, Transesophageal Echocardiography, Intravascular Ultrasound, Computed Tomography and Magnetic Resonance provide vascular interventionists and surgeons with useful diagnostic information for treatment planning. Recent developments in cross-sectional imaging, including multi-modality image fusion and new contrast agents have resulted in improved spatial resolution. Specifically, dynamic Electrocardiographically-Gated Computed Tomographic Angiography (ECG-gated CTA) provides valuable information regarding motion and deformation of the normal and diseased aorta during the cardiac cycle. Extracting and presenting (visualization) of accurate quantitative information from the recorded image data, however remains a challenging task of image post processing. Method The algorithm proposed within this paper processes ECG-gated CTA data (here goes the scanner model and manufacturer) in DICOM (digital imaging and communication in medicine) format, within which the user manually defines an Eulerian Region of Interest (ROI). 2D deformable (active) contour models are used to pre-segment the luminal surfaces of the selected vessels at an arbitrary time point during the cardiac cycle. A tessellation algorithm is used to define the initial configuration of a 3D deformable (active) contour model, which in turn is used for the final segmentation of the luminal surfaces continuously during the cardiac cycle. Specifically, Finite Element (FE) formulations [1] for frames and shells, as known from structural mechanics, are used to define the deformable contour modes. This allows a direct mechanical interpretation of the applied set of reconstruction parameters and leads to an efficient FE implementation of the models [2]; parallel processor architecture is used to solve the global set of non-linear FE equations. Finally displacement and strain measures are derived from the dynamic segmentations and color coded plots are used to visualize, QC 20120420

Abdominal Aortic Aneurysms (AAAs) are defined as a localized permanent dilatation of the infrarenal aorta at least 50 % of its normal diameter. AAAs are frequently diagnosed in the elderly male population and evaluating rupture risk is critically important as aneurysm rupture carries high mortality rates. Growth predictors might be helpful to assess AAA rupture risk and could therefore give a better graded indication for elective repair in order to reduce related mortality without unnecessarily increasing the rate of interventions. Factors associated with AAA growth are still limited but there are some evidence that higher initial AAA diameter is related to faster AAA expansion [1]. The initial dilatation is dependent on elastin degradation, but strength of the AAA is maintained by increased production of collagen. It has been suggested that rupture occurs when collagen production is insufficient to counteract load-bearing at high pressure [2]. AAA growth quantification 30 patients with infrarenal AAAs were included in this study. Criteria for inclusion were 1-year follow-up and availability of at least two high-resolution Computer Tomography-Angiography (CTA) scans. Consequently, 60 CT-A scans were systematically segmented, reconstructed and analyzed (A4research, VASCOPS GmbH), in order to investigate geometrical and mechanical factors likely to be correlated with AAA growth. Derived results were analyzed with an especially developed (automatic) analyzing schema (MatLab, The MathWorks), and the derived information aims at guiding the development of an analytical growth model for AAAs. Constitutive Modeling Collagen is a structural protein responsible for the mechanical strength, stiffness and toughness of biological tissues like skin, tendon, bone, cornea, lung and vasculature. In the present study we considered the enlargement of the aneurysm as a consequence of a pathological degradation and synthesis of collagen, i.e. malfunction of collagen turn-over. Consequen, QC 20120418

The role of suspended minerogenic particles in light scattering in eastern Lake Superior and Keweenaw Bay (II sites) during July of 2006 was evaluated with an individual particle analysis technique (scanning electron microscopy interfaced with automated image and X-ray analyses, SAX), along with bulk paniculate scattering and backscattering coefficients (bp and bbp) and chlorophyll a concentration ([ChI]). SAX measurements provide light-scattering attributes of minerogenic particles, including chemical composition and particle size distribution (PSD). The data were use calculations for estimations of minerogenic scattering and backscattering coefficients (bm and bb,m). The bay had higher concentrations of minerogenic particles and higher values of bm, bb,m. bbp, and the backscattering ratio (bbp : bp) than the pelagic sites. Minerogenic scattering was primarily attributable particles in the size range of I -10 mm. The PSDs deviated from the (Junge) pattern of monotonic increase of particle numbers with decreasing estimates of bm and bb,m combined with those of organic particulate components, as represented by empirical Case 1 bio-optical models, showed closure with bp and bbp, supporting the credibility of the SAX -Mie approach. Variations in the bbp : bp ratio are strongly related to spatial different contributions of phytoplankton vs. minerogenic particles to scattering, with higher values observed where the minerogenic component is more important. SAX can advance the understanding of optical variability by establishing the contributions of well-defined minerogenic constituents that strongly influence optical properties., Pub. in Limnology and Oceanography, v54 n4 p1369-1381, 2009.

Das Sendai Virus (SeV) besitzt zwei Oberflächenproteine, das HN- und das F-Protein. Während das HN-Protein für die Rezeptorbindung zuständig ist, leitet das F-Protein im normalen Infektionsverlauf die Membranfusion ein. Außerdem kann das F-Protein spezifisch mit dem Asialoglykoproteinrezeptor auf Leberzellen interagieren. HN-defiziente SeV stellen somit ein vielversprechendes virales leberzellspezifisces Gentransfersystem dar. Während die initiale Herstellung HN-defizienter SeV ohne Probleme möglich ist, wirft die Vermehrung zu klinisch anwendbaren Mengen Probleme auf. Im Rahmen dieser Arbeit wurde erfolgreich eine HN-Protein exprimierende Helferzelle entwickelt, die als Basis für die Etablierung eines zellulären Hilfssystems für die Vermehrung HN-defizienter SeV dienen wird., Sendai virus (SeV) possesses two surface-glycoproteins, HN and F. During the normal infection cycle, HN-protein mediates receptor binding and F-protein induces membrane fusion. In addition, F-protein is able to interact with the asialoglycoprotein receptor on hepatocytes. HN-deficient SeV are therefore a promising viral hepatocyte-specific gene transfer system. While the initial production of HN-deficient SeV is possible, the amplification to clinical titers is not possible up to now. In this work, an HN-protein expressing helper cell line was successfully developed. This helper cell line will be used to establish a cell-based helper system for the amplification of HN-deficient SeV.

Das Sendai Virus (SeV) besitzt zwei Oberflächenproteine, das HN- und das F-Protein. Während das HN-Protein für die Rezeptorbindung zuständig ist, leitet das F-Protein im normalen Infektionsverlauf die Membranfusion ein. Außerdem kann das F-Protein spezifisch mit dem Asialoglykoproteinrezeptor auf Leberzellen interagieren. HN-defiziente SeV stellen somit ein vielversprechendes virales leberzellspezifisces Gentransfersystem dar. Während die initiale Herstellung HN-defizienter SeV ohne Probleme möglich ist, wirft die Vermehrung zu klinisch anwendbaren Mengen Probleme auf. Im Rahmen dieser Arbeit wurde erfolgreich eine HN-Protein exprimierende Helferzelle entwickelt, die als Basis für die Etablierung eines zellulären Hilfssystems für die Vermehrung HN-defizienter SeV dienen wird., Sendai virus (SeV) possesses two surface-glycoproteins, HN and F. During the normal infection cycle, HN-protein mediates receptor binding and F-protein induces membrane fusion. In addition, F-protein is able to interact with the asialoglycoprotein receptor on hepatocytes. HN-deficient SeV are therefore a promising viral hepatocyte-specific gene transfer system. While the initial production of HN-deficient SeV is possible, the amplification to clinical titers is not possible up to now. In this work, an HN-protein expressing helper cell line was successfully developed. This helper cell line will be used to establish a cell-based helper system for the amplification of HN-deficient SeV.