Mckenziebender3342

PURPOSE Eye gaze tracking is proving to be beneficial in many biomedical applications. The performance of systems based on eye gaze tracking is very much dependent on how accurate their calibration is. It has been reported that the gaze tracking accuracy deteriorates cumulatively and significantly with usage time. This impedes the wide use of gaze tracking in user interfaces. METHODS Explicit re-calibration, typically requiring the user's active attention, is time-consuming and can interfere with the user's main activity. Therefore, we propose an implicit re-calibration method, which can rectify the deterioration of the gaze tracking accuracy without bringing about the user's deliberate attention. We make use of hand-eye coordination, with the reasonable assumption that the eye gaze follows the pointer during a selection task, to acquire additional calibration points during normal usage of a gaze-contingent system. We construct a statistical model for the calibration and the hand-eye coordination and apply the Gaussian process regression framework to perform the re-calibration. RESULTS To validate our model and method, we performed a user study on ultrasonography tasks on a gaze-contingent interface for ultrasound machines. Results suggest that our method can rectify the tracking accuracy deterioration for [Formula see text] of all cases where deterioration occurs in our user study. With another benchmark dataset, our method can redress tracking accuracy to a level comparable to the initial calibration in more than [Formula see text] of the cases. CONCLUSIONS Our implicit re-calibration method is a practical and convenient fix for tracking accuracy deterioration in gaze-contingent user interfaces, and in particular for gaze-contingent ultrasound machines.PURPOSE Surgical simulations play an increasingly important role in surgeon education and developing algorithms that enable robots to perform surgical subtasks. To model anatomy, finite element method (FEM) simulations have been held as the gold standard for calculating accurate soft tissue deformation. Unfortunately, their accuracy is highly dependent on the simulation parameters, which can be difficult to obtain. METHODS In this work, we investigate how live data acquired during any robotic endoscopic surgical procedure may be used to correct for inaccurate FEM simulation results. Since FEMs are calculated from initial parameters and cannot directly incorporate observations, we propose to add a correction factor that accounts for the discrepancy between simulation and observations. We train a network to predict this correction factor. RESULTS To evaluate our method, we use an open-source da Vinci Surgical System to probe a soft tissue phantom and replay the interaction in simulation. We train the network to correct for the difference between the predicted mesh position and the measured point cloud. This results in 15-30% improvement in the mean distance, demonstrating the effectiveness of our approach across a large range of simulation parameters. CONCLUSION We show a first step towards a framework that synergistically combines the benefits of model-based simulation and real-time observations. It corrects discrepancies between simulation and the scene that results from inaccurate modeling parameters. This can provide a more accurate simulation environment for surgeons and better data with which to train algorithms.PURPOSE Neuronavigation systems making use of augmented reality (AR) have been the focus of much research in the last couple of decades. Selleckchem Batimastat In recent years, there has been considerable interest in using mobile devices for AR in the operating room (OR). We propose a complete system that performs real-time AR video augmentation on a mobile device in the context of image-guided neurosurgery. METHODS MARIN (mobile augmented reality interactive neuronavigation system) improves upon the state of the art in terms of performance, allowing real-time augmentation, and interactivity by allowing users to interact with the displayed data. The system was tested in a user study with 17 subjects for qualitative and quantitative evaluation in the context of target localization and brought into the OR for preliminary feasibility tests, where qualitative feedback from surgeons was obtained. RESULTS The results of the user study showed that MARIN performs significantly better in terms of both time ([Formula see text]) and accuracy ([Formula see text]) for the task of target localization in comparison with a traditional image-guided neurosurgery (IGNS) navigation system. Further, MARIN AR visualization was found to be more intuitive and allowed users to estimate target depth more easily. CONCLUSION MARIN improves upon previously proposed mobile AR neuronavigation systems with its real-time performance, higher accuracy, full integration in the normal workflow and greater interactivity and customizability of the displayed information. The improvement in efficiency and usability over previous systems will facilitate bringing AR into the OR.Sirtuin-2 (Sirt2) is a member of the NAD (+)-dependent protein deacetylase family involved in neuroprotection, cellular metabolism, homeostasis, and stress responses after injury of the nervous system. So far, no data have been published describing the role of SIRT2 in motor functional recovery after damage. We found that SIRT2 expression and deacetylase activity were increased within motoneurons after axotomy. To shed light onto the biological relevance of this change, we combined in vitro and in vivo models with pharmacological and genetic ablation approaches. We found that SIRT2 KO (knockout) mice exhibited improved functional recovery after sciatic nerve crush. SIRT2 activity blockage, using AK7, increased neurite outgrowth and length in organotypic spinal cord cultures and human cell line models. SIRT2 blockage enhanced the acetyltransferase activity of p300, which in turn increased the levels of an acetylated form of p53 (Ac-p53 k373), histone 3 (Ac-H3K9), and expression of GAP43, a downstream marker of regeneration. Lastly, we verified that p300 acetyltransferase activity is essential for these effects. Our results suggest that bolstering an epigenetic shift that promotes SIRT2 inhibition can be an effective therapy to increase functional recovery after peripheral nerve injury.