Simulation study of a highly efficient, high resolution X-ry sensor based on self-organizing aluminum oxide

State of the art X-ray imaging sensors comprise a trade-off between the achievable efficiency and the spatial resolution. To overcome such limitations, the use of structured and scintillator filled aluminum oxide (AlOx) matrices has been investigated. We used Monte-Carlo (MC) X-ray simulations to determine the X-ray imaging quality of these AlOx matrices. Important factors which influence the behavior of the matrices are: filling factor (surface ratio between channels and 'closed' AlOx), channel diameter, aspect ratio, filling material etc. Therefore we modeled the porous AlOx matrix in several different ways with the MC X-ray simulation tool ROSI [1] and evaluated its properties to investigate the achievable performance at different X-ray spectra, with different filling materials (i.e. scintillators) and varying channel height and pixel readout. In this paper we focus on the quantum efficiency, the spatial resolution and image homogeneity

Colonic epithelial ion transport is not affected in patients with diverticulosis

<p>Abstract</p> <p>Background</p> <p>Colonic diverticular disease is a bothersome condition with an unresolved pathogenesis. It is unknown whether a neuroepithelial dysfunction is present. The aim of the study was two-fold; (1) to investigate colonic epithelial ion transport in patients with diverticulosis and (2) to adapt a miniaturized Modified Ussing Air-Suction (MUAS) chamber for colonic endoscopic biopsies.</p> <p>Methods</p> <p>Biopsies were obtained from the sigmoid part of the colon. 86 patients were included. All patients were referred for colonoscopy on suspicion of neoplasia and they were without pathological findings at colonoscopy (controls) except for diverticulosis in 22 (D-patients). Biopsies were mounted in MUAS chambers with an exposed area of 5 mm². Electrical responses to various stimulators and inhibitors of ion transport were investigated together with histological examination. The MUAS chamber was easy to use and reproducible data were obtained.</p> <p>Results</p> <p>Median basal short circuit current (SCC) was 43.8 μA·cm^-2(0.8 – 199) for controls and 59.3 μA·cm^-2(3.0 – 177.2) for D-patients. Slope conductance was 77.0 mS·cm^-2(18.6 – 204.0) equal to 13 Ω·cm²for controls and 96.6 mS·cm^-2(8.4 – 191.4) equal to 10.3 Ω·cm²for D-patients. Stimulation with serotonin, theophylline, forskolin and carbachol induced increases in SCC in a range of 4.9 – 18.6 μA·cm^-2, while inhibition with indomethacin, bumetanide, ouabain and amiloride decreased SCC in a range of 6.5 – 27.4 μA·cm^-2, and all with no significant differences between controls and D-patients. Histological examinations showed intact epithelium and lamina propria before and after mounting for both types of patients.</p> <p>Conclusion</p> <p>We conclude that epithelial ion transport is not significantly altered in patients with diverticulosis and that the MUAS chamber can be adapted for studies of human colonic endoscopic biopsies.</p

Lack of Chemokine Signaling through CXCR5 Causes Increased Mortality, Ventricular Dilatation and Deranged Matrix during Cardiac Pressure Overload

RATIONALE: Inflammatory mechanisms have been suggested to play a role in the development of heart failure (HF), but a role for chemokines is largely unknown. Based on their role in inflammation and matrix remodeling in other tissues, we hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling during HF. OBJECTIVE: We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5 in cardiac pathophysiology leading to HF. METHODS AND RESULTS: Mice harboring a systemic knockout of the CXCR5 (CXCR5(-/-)) displayed increased mortality during a follow-up of 80 days after aortic banding (AB). Following three weeks of AB, CXCR5(-/-) developed significant left ventricular (LV) dilatation compared to wild type (WT) mice. Microarray analysis revealed altered expression of several small leucine-rich proteoglycans (SLRPs) that bind to collagen and modulate fibril assembly. Protein levels of fibromodulin, decorin and lumican (all SLRPs) were significantly reduced in AB CXCR5(-/-) compared to AB WT mice. Electron microscopy revealed loosely packed extracellular matrix with individual collagen fibers and small networks of proteoglycans in AB CXCR5(-/-) mice. Addition of CXCL13 to cultured cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF, we observed increased myocardial levels of CXCR5 and SLRPs, which was reversed following LV assist device treatment. CONCLUSIONS: Lack of CXCR5 leads to LV dilatation and increased mortality during pressure overload, possibly via lack of an increase in SLRPs. This study demonstrates a critical role of the chemokine CXCL13 and CXCR5 in survival and maintaining of cardiac structure upon pressure overload, by regulating proteoglycans essential for correct collagen assembly

Contemporary Management of Locally Advanced and Recurrent Rectal Cancer: Views from the PelvEx Collaborative

Pelvic exenteration is a complex operation performed for locally advanced and recurrent pelvic cancers. The goal of surgery is to achieve clear margins, therefore identifying adjacent or involved organs, bone, muscle, nerves and/or vascular structures that may need resection. While these extensive resections are potentially curative, they can be associated with substantial morbidity. Recently, there has been a move to centralize care to specialized units, as this facilitates better multi-disciplinary care input. Advancements in pelvic oncology and surgical innovation have redefined the boundaries of pelvic exenterative surgery. Combined with improved neoadjuvant therapies, advances in diagnostics, and better reconstructive techniques have provided quicker recovery and better quality of life outcomes, with improved survival This article provides highlights of the current management of advanced pelvic cancers in terms of surgical strategy and potential future developments

Operational Experiences with X Ray Tomography for SRF Cavity Shape and Surface Control

X ray tomography has been established as a nondestructive three dimensional analysis tool, commercially offered by industrial vendors. Typical applications cover shape control and failure detection voids, cracks deep inside of complicated bulk pieces like engine blocks, bearings, turbine blades etc.. We evaluated the applicability of the process for superconducting radio frequency cavities, in particular a generic 1.3 GHz single test cell cavity, the 1.4 cell 1.3 GHz bERLinPro electron gun cavity and the 1.5 GHz VSR 1 cell prototype cavity. The gun cavity experienced severe shape modifications during its tuning process and features a complicated internal stiffening construction. Thus it is a challenge to measure its actual internal cavity surface shape after the complete preparation process with a resolution, sufficiently high better than 0.2 mm to serve as input for meaningful comparative field simulations. First tests with a vendor s on site X ray source, operating at X ray energies up to 590 keV revealed an insufficient resolution of the inner surface, attributed to the unfavorable X ray damping characteristics of niobium. This was overcome with the aid of an accelerator based source X ray spectrum up to 7.5 MeV , operated by Fraunhofer IISEZRT, Fürth, Germany. Results show significant, while understood, shape changes and indicate partial inner surface modifications of the gun cavity. Further, the data evaluation process, which was needed to provide input for field simulations, raised issues because of data set size and complexity and illustrated further some typical artefacts, which are discussed in the pape

3-D scanning of sea freight containers using MeV X-rays

The ECSIT project analyses how innovative inspection technologies can lead to an enhanced container security and how these technologies can be embedded into a holistic concept. It has the goal to analyze the possibility and feasibility for 100% scanning of all containers which are shipped to US ports and to develop a concept for integrating necessary infrastructure. A key element of the entire concept is the scanning technology itself. MeV X-ray technology using a linear accelerator as radiation source provides the feasibility to visualize the content of a container without opening it. If a 2-D radiography is ambiguous, a 3-D evaluation of the respective location could be conducted. MeV X-ray computed tomography (CT) is such a method to provide 3-D information of the content of a container. In the context of ECSIT, Fraunhofer EZRT has developed the concept of such a continuative high energy X-ray scanning stage and evaluated its application to sea freight containers. In this paper different approaches for measuring a 3-D tomographic volume data set of objects which are very heavy and thus difficult to move in arbitrary directions will be discussed. Three different geometrical principles for data acquisition were evaluated: laminography, limited angle CT, and a gantry CT. The volume data sets were reconstructed by using a standard filtered back projection and different algebraic reconstruction techniques (ART). Real 3-D volume data of large objects measured with the set-up described above are presented. As test objects a real container packed with various typical goods like furniture or consumer electronics as well as simulated threats like a bomb mock-up was used