135 resultados para polarization beam splitter
Resumo:
This retrospective radiographic study analyzed the dimensions of the alveolar bone in the posterior dentate mandible based on cone beam computed tomography (CBCT) images. A total of 56 CBCT images met the inclusion criteria, resulting in a sample size of 122 cross sections showing posterior mandibular teeth (premolars and molars). The thickness of the buccal and lingual bone walls was measured at two locations: 4 mm apical to the cementoenamel junction (measurement point 1, MP1) and at the middle of the root (measurement point 2, MP2). Further, alveolar bone width was assessed at the level of the most coronal buccal bone detectable (alveolar bone width 1, BW1) and at the superior border of the mandibular canal (alveolar bone width 2, BW2). The vertical distance between the two as well as the presence of a lingual undercut were also analyzed. There was a steady increase in buccal bone wall thickness from the first premolar to the second molar at both MP1 and MP2. BW1 at the level of the premolars was significantly thinner than that for molars. Alveolar bone height was constant for all teeth examined. For the selection of an appropriate postextraction treatment approach, analysis of the alveolar bone dimensions at the tooth to be extracted by means of CBCT can offer valuable information concerning bone volume and morphology at the future implant site.
Resumo:
The purpose of the present study was to evaluate the thickness and the anatomic characteristics of the Schneiderian membrane and cortical bone using limited cone beam computed tomography (CBCT) scannning in patients referred for planning of apical surgery of maxillary molars.
Resumo:
Ocular anatomy and radiation-associated toxicities provide unique challenges for external beam radiation therapy. For treatment planning, precise modeling of organs at risk and tumor volume are crucial. Development of a precise eye model and automatic adaptation of this model to patients' anatomy remain problematic because of organ shape variability. This work introduces the application of a 3-dimensional (3D) statistical shape model as a novel method for precise eye modeling for external beam radiation therapy of intraocular tumors.
Resumo:
To analyze the effect of primary Gleason (pG) grade among a large cohort of Gleason 7 prostate cancer patients treated with external beam radiation therapy (EBRT).
Resumo:
Theileria annulata is an intracellular protozoan parasite that infects B cells and macrophages of ruminants. Macrophages infected with T. annulata are de-differentiated and display tumour cell properties and a metastatic behaviour. How parasitized cells adapt their morphology, motility and invasive behaviour has not yet been addressed in detail. In this study, I investigated the regulation of host cell actin dynamics in T. annulata-transformed macrophages and how this affects host cell morphology and motility. T. annulata was found to promote the formation of filamentous-actin-rich podosome-type adhesions (PTAs) and lamellipodia, and to establish a polarized morphology of the infected cell. Characteristic for parasite-dependent host cell polarization is that infected cells display a single, persistent lamellipodium. Src kinases--in particular Hck--are required for the polar extension of this lamellipodium. Hck does so by promoting the clustered assembly of PTAs and accumulation of proteins of the Ezrin, Radixin, Moesin (ERM) family in lamellipodia. Polar accumulation of PTAs and ERM proteins correlates with focal matrix degradation underneath lamellipodia. These findings suggest that T. annulata equips its host cell with properties to adhere and invade. These properties are likely to promote the motile behaviour required for dissemination of infected cells in vivo.
Resumo:
Brain edema is the main cause of death from brain infarction. The polarized expression of the water channel protein aquaporin-4 (AQP4) on astroglial endfeet surrounding brain microvessels suggests a role in brain water balance. Loss of astrocyte foot process anchoring to the basement membrane (BM) accompanied by the loss of polarized localization of AQP4 to astrocytic endfeet has been shown to be associated with vasogenic/extracellular edema in neuroinflammation. Here, we asked if loss of astrocyte polarity is also observed in cytotoxic/intracellular edema following focal brain ischemia after transient middle cerebral artery occlusion (tMCAO). Upon mild focal brain ischemia, we observed diminished immunostaining for the BM components laminin α4, laminin α2, and the proteoglycan agrin, in the core of the lesion, but not in BMs in the surrounding penumbra. Staining for the astrocyte endfoot anchorage protein β-dystroglycan (DG) was dramatically reduced in both the lesion core and the penumbra, and AQP4 and Kir4.1 showed a loss of polarized localization to astrocytic endfeet. Interestingly, we observed that mice deficient for agrin expression in the brain lack polarized localization of β-DG and AQP4 at astrocytic endfeet and do not develop early cytotoxic/intracellular edema following tMCAO. Taken together, these data indicate that the binding of DG to agrin embedded in the subjacent BM promotes polarized localization of AQP4 to astrocyte endfeet. Reduced DG protein levels and redistribution of AQP4 as observed upon tMCAO might therefore counteract early edema formation and reflect a beneficial mechanism operating in the brain to minimize damage upon ischemia.
Resumo:
The ArgoNeuT liquid argon time projection chamber has collected thousands of neutrino and anti-neutrino events during an extended run period in the NuMI beam-line at Fermilab. This paper focuses on the main aspects of the detector layout and related technical features, including the cryogenic equipment, time projection chamber, read-out electronics, and off-line data treatment. The detector commissioning phase, physics run, and first neutrino event displays are also reported. The characterization of the main working parameters of the detector during data-taking, the ionization electron drift velocity and lifetime in liquid argon, as obtained from through-going muon data complete the present report.