Actuating Compact Augmented Reality Devices by Artificial Muscle

An artificial muscle actuator resolves practical engineering problems in compact wearable devices, which are limited to conventional actuators such as electromagnetic actuators. Abstracting the fundamental advantages of an artificial muscle actuator provides a small-scale, high-power actuating system for developing varifocal augmented reality (AR) glasses and naturally fit haptic gloves. Here, we design a shape memory alloy (SMA)-based lightweight and high-power artificial muscle actuator, the so-called compliant amplified SMA actuator (CASA). Despite its light weight (0.22 g), the CASA has a high power density of 1.7 kW/kg and an actuation strain of 300%. We show how CASA enables image depth control and an immersive tactile response in the form of AR glasses and haptic gloves whose thin form factor and high power density can hardly be achieved by conventional actuators.

Somatosensory processing deficits and altered cortico-hippocampal connectivity in Shank3b-/- mice

Abnormal tactile response is considered an integral feature of Autism Spectrum Disorders (ASDs), and hypo-responsiveness to tactile stimuli is often associated with the severity of ASDs core symptoms. Patients with Phelan-McDermid syndrome (PMS), caused by mutations in the SHANK3 gene, show ASD-like symptoms associated with aberrant tactile responses. However, the neural underpinnings of these somatosensory abnormalities are still poorly understood. Here we investigated, in Shank3b-/- adult mice, the neural substrates of whisker-guided behaviors, a key component of rodents' interaction with the surrounding environment. To this aim, we assessed whisker-dependent behaviors in Shank3b-/- adult mice and age-matched controls, using the textured novel object recognition (tNORT) and whisker nuisance (WN) test. Shank3b-/- mice showed deficits in whisker-dependent texture discrimination in tNORT and behavioral hypo-responsiveness to repetitive whisker stimulation in WN. Notably, sensory hypo-responsiveness was accompanied by a significantly reduced activation of the primary somatosensory cortex (S1) and hippocampus, as measured by c-fos mRNA in situ hybridization, a proxy of neuronal activity following whisker stimulation. Moreover, resting-state fMRI showed a significantly reduced S1-hippocampal connectivity in Shank3b mutant mice. Together, these findings suggest that impaired crosstalk between hippocampus and S1 might underlie Shank3b-/- hypo-reactivity to whisker-dependent cues, highlighting a potentially generalizable form of dysfunctional somatosensory processing in ASD.

Intubating Conditions with three different doses of Rocuronium in surgery of cancer patients

Background: This is a prospective randomized, double blind study to determine the doses of rocuronium that would give 90% and 95% probabilities of successful tracheal intubation within 60s after administration. This study evaluated intubating conditions and duration of action of 0.4 mg, 0.8 mg and 1.2 mg of rocuronium, administered intravenously in patients undergoing elective surgical procedures. Goal in this study is to define doses level of rocuronium that would provide optimal relaxation for tracheal intubation in patients in whom succinylcholine was relatively contraindicated. Methods: Sixty patients both male and female, ASA I & II, age between 18–60 years, with BMI of less that 30 who were planned for elective surgical procedures were randomized into three groups. Group A received 0.4 mg (n=20), Group B received 0.8 mg (n=20) and Group C received 1.2 mg (n=20) of rocuronium. At 60 seconds after injection of the rocuronium, laryngoscopy was initiated, with the goal being endotracheal tube passed through the patient's vocal cords and the cuff inflated within the trachea in 20s. Intubating conditions was graded excellent, good or poor according to Cooper scoring system criteria. When the patient lost consciousness, train-of-four (TOF) stimulation (at 2 Hz and repeated every 12s) were recorded. Immediately after tracheal intubation and every 5 min thereafter the investigator counted the number of tactile TOF responses. The duration of action of rocuronium was defined as the time from the end of injection of rocuronium until reappearance of first tactile response to TOF stimulation. Results: There were twelve patients in the 0.4mg/kg rocuronium group, two in the 0.8mg/kg group, and one in the 1.2mg/kg rocuronium group with an unacceptable intubation grade caused by sustained coughing at intubation. The D90 and D95 doses were 0.83(0.59 -1.03) and 1.04 (0.76-1.36) mg/kg, respectively. Estimated time until first tactile train-of-four response after D50 and D95 doses were 43min and 52 min, respectively. Conclusion: After induction with pethedine and sodium thiopentone, rocuronium in a dose of 0.8mg/kg produces equivalent intubating conditions as that of 1.2mg/kg after 60 seconds of administration

Virtual simulation system for prosthodontics. Part I

Current computerized technologies introduced into dental prosthetics use 3D imaging, simulation systems, virtual reality. The virtual reality system, based on haptic technology, is a new instrument in the teaching process, still developing. The necessity to implement virtual reality technology has emerged from the fact that medical practice has been restricted to patients in recent years. Virtual reality systems have been introduced in order to practice certain clinical maneuvers and to acquire specific skills. Actual, virtual technology is at the stage where offers advanced simulations to users by combining visual and tactile response. The efficiency of e-learning platforms is increased when including virtual reality technologies. Thus, a new, interactive concept is introduced.