Extraction of orientation from floor structure for odometry correction in mobile robotics

Abstract. We are presenting a method for correcting odometry readings of a robot for increased accuracy of position estimation. Our method uses a simple pragmatic approach and exploits the distinct structure of the floor in our experimental area. By continually extracting orientation information from the floor view, we are able to correct the heading component of odometry, thereby eliminating the major source for position errors. Compared to other approaches the solution is computationally inexpensive. Our experiments show that by employing our correction method we are able to significantly increase position accuracy and consistently map paths up to several hundred meters.

Serum S100B protein is specifically related to white matter changes in schizophrenia

Background: Schizophrenia can be conceptualized as a form of dysconnectivity between brain regions. To investigate the neurobiological foundation of dysconnectivity, one approach is to analyze white matter structures, such as the pathology of fiber tracks. S100B is considered a marker protein for glial cells, in particular oligodendrocytes and astroglia, that passes the blood brain barrier and is detectable in peripheral blood. Earlier Studies have consistently reported increased S100B levels in schizophrenia. In this study, we aim to investigate associations between S100B and structural white matter abnormalities.Methods: We analyzed data of 17 unmedicated schizophrenic patients (first and recurrent episode) and 22 controls. We used voxel based morphometry (VBM) to detect group differences of white matter structures as obtained from T1-weighted MR-images and considered S100B serum levels as a regressor in an age-corrected interaction analysis. Results: S100B was increased in both patient subgroups. Using VBM, we found clusters indicating significant differences of the association between S100B concentration and white matter. Involved anatomical structures are the posterior cingulate bundle and temporal white matter structures assigned to the superior longitudinal fasciculus. Conclusions: S100B-associated alterations of white matter are shown to be existent already at time of first manifestation of psychosis and are distinct from findings in recurrent episode patients. This suggests involvement of S100B in an ongoing and dynamic process associated with structural brain changes in schizophrenia. However, it remains elusive whether increased S100B serum concentrations in psychotic patients represent a protective response to a continuous pathogenic process or if elevated S100B levels are actively involved in promoting structural brain damage

Shaping ability of four root canal instrumentation systems in simulated 3D-printed root canal models

<div><p>Introduction</p><p>The aim of this study was to compare the shaping ability of four root canal preparation systems in newly developed 3D-printed root canal models.</p><p>Materials and methods</p><p>For this study, 1080 3D-printed acrylic resin blocks with nine different root canal configurations were produced. They were prepared with Reciproc R25 (#25), F6 SkyTaper (#25 and #30) F360 (#25 and #35) and One Shape (#25) (N = 30 per system). Pre- and post-instrumentation images were superimposed for evaluation of the centering ratio of the different systems. Ledges, instrument fractures and preparation times were also recorded. Analysis of variance (ANOVA) and post-hoc Tukey tests were conducted, comparing the mean canal centering ratios and the mean preparation times.</p><p>Results</p><p>There were significant differences between all systems regarding the centering ratios in the different root canal configurations (ANOVA p < 0.001). The root canal configuration had considerable effect on the centering ratio of the instruments. The best overall mean centering ratios were achieved with F6 SkyTaper #25 instruments especially in canal configurations with big curvature angles and radii, while F360 #35 was least centered especially in canals with small curvature angles and radii. Most ledges occurred with OneShape, while it was the significantly (p < 0.001) fastest preparation system (86.7 s (SD 13.53)) and Reciproc the significantly (p < 0.001) slowest (103.0 s (SD 20.67)).</p><p>Conclusion</p><p>3D-printed root canals are suitable to produce challenging canal configurations and to investigate the limitations of root canal instruments. We found that all instruments caused canal transportations. However, F6 SkyTaper #25 files had better overall centering ratios than the other instruments. In canal configurations with small curvature radii, the centering ratio of some instruments is low and the probability for ledges is increased.</p></div

Schematic illustration of the function of the experimental software used to evaluate the centering ratios of the root canal preparations.

<p>Superimposed images with traced outlines of un-instrumented (green and blue lines) and instrumented (red and yellow lines) root canals with software assisted construction of tangents and perpendiculars crossing the outlines of the superimposed root canals. <b>Z</b>: current measuring point, <b>A</b> & <b>B</b>: neighbor auxiliary points at intervals of 15 pixels to Z, <b>g</b>: straight line constructed crossing <b>A</b> & <b>B</b>, <b>t</b>: tangent constructed intersecting <b>Z</b> by parallel shift to <b>g</b>, <b>s</b>: perpendicular intersecting <b>g</b> and <b>t</b> in <b>Z</b>, <b>a</b> & <b>b</b>: amount of canal wall removal detected by the software.</p

Shaping ability of four root canal instrumentation systems in simulated 3D-printed root canal models - Fig 4

<p><b>A</b> Error bar plots (symbol: mean value; whiskers: minimum and maximum value) of mean centering ratios for the different instrument systems used for the different root canal configurations. <b>B</b> Error bar plots of mean centering ratios for the different canal configurations with the different instrument systems. (Asterisks indicate significant differences (p<0.05).</p

Overview of the significant differences between the systems in the different canal configurations.

<p>Green fields indicate a significant (p<0.05) better centering ratio of the file system in lines compared to the file in the specified canal configuration in the corresponding column. Red fields indicate significant (p<0.05) lower centering ratios and yellow fields indicate no significant difference.</p

A γ-secretase-like intramembrane cleavage of TNFα by the GxGD aspartyl protease SPPL2b

Gamma-secretase and signal peptide peptidase (SPP) are unusual GxGD aspartyl proteases, which mediate intramembrane proteolysis. In addition to SPP, a family of SPP-like proteins (SPPLs) of unknown function has been identified. We demonstrate that SPPL2b utilizes multiple intramembrane cleavages to liberate the intracellular domain of tumor necrosis factor alpha (TNFalpha) into the cytosol and the carboxy-terminal counterpart into the extracellular space. These findings suggest common principles for regulated intramembrane proteolysis by GxGD aspartyl proteases

Hyperalgesia by low doses of the local anesthetic lidocaine involves cannabinoid signaling: An fMRI study in mice

Lidocaine is clinically widely used as a local anesthetic inhibiting propagation of action potentials in peripheral nerve fibers. Correspondingly, the functional magnetic resonance imaging (fMRI) response in mouse brain to peripheral noxious input is largely suppressed by local lidocaine administered at doses used in a clinical setting. We observed, however, that local administration of lidocaine at doses 100 × lower than that used clinically led to a significantly increased sensitivity of mice to noxious forepaw stimulation as revealed by fMRI. This hyperalgesic response could be confirmed by behavioral readouts using the von Frey filament test. The increased sensitivity was found to involve a type 1 cannabinoid (CB(1)) receptor-dependent pathway as global CB(1) knockout mice, as well as wild-type mice pretreated systemically with the CB(1) receptor blocker rimonabant, did not display any hyperalgesic effects after low-dose lidocaine. Additional experiments with nociceptor-specific CB(1) receptor knockout mice indicated an involvement of the CB(1) receptors located on the nociceptors. We conclude that low concentrations of lidocaine leads to a sensitization of the nociceptors through a CB(1) receptor-dependent process. This lidocaine-induced sensitization might contribute to postoperative hyperalgesia