Hybrid Video/Optical See-Through HMD

An old but still ongoing subject of debate among augmented reality (AR) experts is about which see-through paradigm is best in wearable AR displays. Video see-through (VST) and optical see-through (OST) paradigms have both their own strengths and shortcomings with respect to technological and human-factor aspects. The major difference between these see-through paradigms is in providing an aided (VST) or unaided (OST) view of the real world. In this work, we present a novel approach for the development of AR stereoscopic head-mounted displays (HMDs) that can provide both the see-through mechanisms. Our idea is to dynamically modify the transparency of the display through a liquid crystal (LC)-based electro-optical shutter applied on the top of a standard OST device opportunely modified for housing a pair of external cameras. A plane-induced homography transformation is used for consistently warping the video images, hence reducing the parallax between cameras and displays. An externally applied drive voltage is used for smoothly controlling the light transmittance of the LC shutters so as to allow an easy transition between the unaided and the camera-mediated view of the real scene. Our tests have proven the efficacy of the proposed solution under worst-case lighting conditions

DEMNUni: cross-correlating the nonlinear ISWRS effect with CMB-lensing and galaxies in the presence of massive neutrinos

We present a novel analytical approach to study the cross-correlations between the Integrated Sachs Wolfe--Rees Sciama (ISWRS) effects and large-scale structure tracers in the presence of massive neutrinos. Our method has been validated against large N-body simulations with a massive neutrino particle component, namely the DEMNUni suite. We investigate the impact of different neutrino masses on the cross-correlations between ISWRS and both Cosmic Microwave Background (CMB) lensing and galaxies. We show that the position of the sign inversion due to nonlinear effects is strongly related to the neutrino mass. While such nonlinear cross-correlation signals may not be able alone to constrain the neutrino mass, our approach paves the way for future studies to detect the amplitude of these cross-spectra on small scales, and to explore the combined impact of dark energy and neutrino mass from future galaxy surveys and CMB experiments.Comment: 31 pages , 15 fig

Review of the Augmented Reality Systems for Shoulder Rehabilitation

Literature shows an increasing interest for the development of augmented reality (AR) applications in several fields, including rehabilitation. Current studies show the need for new rehabilitation tools for upper extremity, since traditional interventions are less effective than in other body regions. This review aims at: Studying to what extent AR applications are used in shoulder rehabilitation, examining wearable/non-wearable technologies employed, and investigating the evidence supporting AR effectiveness. Nine AR systems were identified and analyzed in terms of: Tracking methods, visualization technologies, integrated feedback, rehabilitation setting, and clinical evaluation. Our findings show that all these systems utilize vision-based registration, mainly with wearable marker-based tracking, and spatial displays. No system uses head-mounted displays, and only one system (11%) integrates a wearable interface (for tactile feedback). Three systems (33%) provide only visual feedback; 66% present visual-audio feedback, and only 33% of these provide visual-audio feedback, 22% visual-audio with biofeedback, and 11% visual-audio with haptic feedback. Moreover, several systems (44%) are designed primarily for home settings. Three systems (33%) have been successfully evaluated in clinical trials with more than 10 patients, showing advantages over traditional rehabilitation methods. Further clinical studies are needed to generalize the obtained findings, supporting the effectiveness of the AR applications

Effects of onabotulintoxinA on habituation of laser evoked responses in chronic migraine

Onabotulintoxin A (BontA) is an efficacious preventive treatment for chronic migraine, though the specific mechanism of action is still under discussion. The study aims: (1) To evaluate pain processing modifications in chronic migraine patients (CM) under single BontA administration in pericranial muscles, by means of CO2 Laser Evoked Potentials (LEPs) obtained by the stimulation of the skin over the right frontal and trapezius injection sites and hand dorsum, in a double blind placebo controlled crossover design. (2) To correlate main LEPs findings with clinical outcome after one year of BontA treatment. Twenty refractory CM patients were included in the analysis. The LEPs were recorded in basal conditions and seven days after BontA (PREEMPT protocol) and saline solution injection. The N1, N2 and P2 amplitude and latencies and N2P2 habituation index were evaluated and correlated with the percent change of headache frequency after one year of toxin treatment. After seven days of BontA treatment, a normalization of the trigeminal habituation index was observed, which was correlated with the clinical outcome after one year of BontA therapy. Patients displaying trigeminal LEPs facilitation at T0 time showed a more efficient therapeutic outcome. Neurotoxin may exert a modulating effect on trigeminal nociception, normalizing central neurotransmission

Bioengineering, augmented reality, and robotic surgery in vascular surgery: A literature review

Biomedical engineering integrates a variety of applied sciences with life sciences to improve human health and reduce the invasiveness of surgical procedures. Technological advances, achieved through biomedical engineering, have contributed to significant improvements in the field of vascular and endovascular surgery. This paper aims to review the most cutting-edge technologies of the last decade involving the use of augmented reality devices and robotic systems in vascular surgery, highlighting benefits and limitations. Accordingly, two distinct literature surveys were conducted through the PubMed database: the first review provides a comprehensive assessment of augmented reality technologies, including the different techniques available for the visualization of virtual content (11 papers revised); the second review collects studies with bioengineering content that highlight the research trend in robotic vascular surgery, excluding works focused only on the clinical use of commercially available robotic systems (15 papers revised). Technological flow is constant and further advances in imaging techniques and hardware components will inevitably bring new tools for a clinical translation of innovative therapeutic strategies in vascular surgery

Radiologic Cerebral Reperfusion at 24 h Predicts Good Clinical Outcome

Cerebral reperfusion and arterial recanalization are radiological features of the effectiveness of thrombolysis in acute ischemic stroke (AIS) patients. Here, an investigation of the prognostic role of early recanalization/reperfusion on clinical outcome was performed. In AIS patients (n = 55), baseline computerized tomography (CT) was performed 64 8 h from symptom onset, whereas CT determination of reperfusion/recanalization was assessed at 24 h. Multiple linear and logistic regression models were used to correlate reperfusion/recanalization with radiological (i.e., hemorrhagic transformation, ischemic core, and penumbra volumes) and clinical outcomes (assessed as National Institutes of Health Stroke Scale [NIHSS] reduction 65 8 points or a NIHSS 64 1 at 24 h and as modified Rankin Scale [mRS] < 2 at 90 days). At 24 h, patients achieving radiological reperfusion were n = 24, while the non-reperfused were n = 31. Among non-reperfused, n = 15 patients were recanalized. Radiological reperfusion vs. recanalization was also confirmed by early increased levels of circulating inflammatory biomarkers (i.e., serum osteopontin). In multivariate analysis, ischemic lesion volume reduction was associated with both recanalization (\u3b2 = 0.265; p = 0.014) and reperfusion (\u3b2 = 0.461; p < 0.001), but only reperfusion was independently associated with final infarct volume (\u3b2 = 12 0.333; p = 0.007). Only radiological reperfusion at 24 h predicted good clinical response at day 1 (adjusted OR 16.054 [1.423\u2013181.158]; p = 0.025) and 90-day good functional outcome (adjusted OR 25.801 [1.483\u2013448.840]; p = 0.026). At ROC curve analysis the AUC of reperfusion was 0.777 (p < 0.001) for the good clinical response at 24 h and 0.792 (p < 0.001) for 90-day clinical outcome. Twenty-four-hour radiological reperfusion assessed by CT is associated with good clinical response on day 1 and good functional outcome on day 90 in patients with ischemic stroke

Use of Knee Fractures Physical Replicas for Surgical Training and Rehearsal: Proof of Concept Study

In the last years also in orthopedic surgery, there was an increasing interest in the development of surgical simulators using methods of additive manufacturing combined or not with augmented reality systems (hybrid simulators). Aim of this work was to evaluate the use of a new patient’s specific tibial plateau fractures simulator for surgical training of young resident surgeons in fracture fixation with an external fixator. The simulator is a realistic knee phantom including a patient-specific replica of a fractured tibia and fibula, obtained by CT segmentation and rapid prototyping techniques. Each training session started with the presentation, and planning, of the surgical case that it was followed by the external fixation session on the simulator. At the end of each session, all participants were asked to fill out a questionnaire, concerning the phantom realism and appropriateness as a teaching modality. The results of the Likert Questionnaire indicating that there is an overall significant agreement with the phantom realism and its appropriateness as a teaching modality. The solid model of the patient’s anatomy can faithfully reproduce the surgical complexity of the patient and it allows to generate surgical simulators with an increasing difficulty to perform structured training paths: from the "simple" case to the "complex" case. The use of simulators based on 3D models has proved to be a very useful tool both for didactic and surgical training purposes, allowing surgeons to perform a real procedure simulation outside the surgical room

A Molecular Mechanism to Explain the Nickel-Induced Changes in Protamine-like Proteins and Their DNA Binding Affecting Sperm Chromatin in Mytilus galloprovincialis: An In Vitro Study

: Nickel is associated with reproductive toxicity, but little is known about the molecular mechanisms of nickel-induced effects on sperm chromatin and protamine-like proteins (PLs). In the present work, we analyzed PLs from Mytilus galloprovincialis by urea-acetic acid polyacrylamide gel electrophoresis (AU-PAGE) and SDS-PAGE and assessed their binding to DNA by Electrophoretic Mobility Shift Assay (EMSA) after exposing mussels to 5, 15, and 35 µM NiCl2 for 24 h. In addition, a time course of digestion with MNase and release of PLs from sperm nuclei by the NaCl gradient was performed. For all exposure doses, in AU-PAGE, there was an additional migrating band between PL-III and PL-IV, corresponding to a fraction of PLs in the form of peptides detected by SDS-PAGE. Alterations in DNA binding of PLs were observed by EMSA after exposure to 5 and 15 µM NiCl2, while, at all NiCl2 doses, increased accessibility of MNase to sperm chromatin was found. The latter was particularly relevant at 15 µM NiCl2, a dose at which increased release of PLII and PLIII from sperm nuclei and the highest value of nickel accumulated in the gonads were also found. Finally, at all exposure doses, there was also an increase in PARP expression, but especially at 5 µM NiCl2. A possible molecular mechanism for the toxic reproductive effects of nickel in Mytilus galloprovincialis is discussed