A fully autonomous terrestrial bat-like acoustic robot.

Echolocating bats rely on active sound emission (echolocation) for mapping novel environments and navigating through them. Many theoretical frameworks have been suggested to explain how they do so, but few attempts have been made to build an actual robot that mimics their abilities. Here, we present the 'Robat'-a fully autonomous bat-like terrestrial robot that relies on echolocation to move through a novel environment while mapping it solely based on sound. Using the echoes reflected from the environment, the Robat delineates the borders of objects it encounters, and classifies them using an artificial neural-network, thus creating a rich map of its environment. Unlike most previous attempts to apply sonar in robotics, we focus on a biological bat-like approach, which relies on a single emitter and two ears, and we apply a biological plausible signal processing approach to extract information about objects' position and identity.

Closed loop control of microscopic particles incorporating steady streaming and visual feedback.

Automatic manipulation of microscopic particles is very important in biology, especially in new lab-on-chip systems for automatic testing and DNA manipulation. We suggest a particle manipulation system (PMS) based on vibrating piezoelectric beams creating steady streaming flow in a viscous liquid. The flow is nearly unidirectional and it is used to control the position and velocity of the particles in the workspace of the PMS. The particles position in the PMS are controlled by visual feedback. This study presents the manipulation method, the system's model describing its behavior and characterizes experimentally its performance. The PMS is capable moving a 2-200 µm particle in a workspace of 8x8 mm2 with an absolute accuracy of 0.2 µm. The characteristic velocity in 500 cP Si oil, is 20 µm/s using an actuation voltage amplitude of 5 V and can reach 250 µm/s using 15 V respectively. We can also move a constellation of several particles in various sizes without changing the distance between them. The accuracy of the manipulation can be increased by enhancing the amplification of the microscope on the expanse of a smaller workspace field of view.

Characterization of steady streaming for a particle manipulation system.

Accurate positioning of biological cells or microscopic particle without directly contacting them is a challenging task in biomedical engineering. Various trapping methods for controlling the position of a particle have been suggested. The common driving methods are based on laser and ultrasonic actuation principles. In this work we suggest a design for a hydrodynamic particle manoeuvring system. The system operates using steady streaming in a viscous fluid media induced by high frequency vibration of piezoelectric cantilevers. A particle within the workspace of the system can be trapped and manipulated to a desired position by the fairly unidirectional flow field created by the beams. In this paper, the flow field in the particle manipulation system is characterized numerically and experimentally. We find that the flow field resembles the analytical solutions of a flow field created by an oscillating sphere. Furthermore, we validate numerically the quadratic relation between the steady streaming velocity and the vibration amplitude of the beam. The calibration of the piezoelectric actuator's oscillation amplitudes enables effective positioning of particles with a diameter of 20 um to 1 mm. We find that a 30X0.8X2 mm(3) piezoelectric beam vibrating at its first resonance frequency, 200 Hz, is able to move a particle at a typical flow velocity ranging between 0.05 mm/sec and 0.13 mm/s in 430 cSt Si oil (Re=0.2).

Internet Addiction and COVID-19 Misbeliefs Among Hungarian Online Gamers: A Cross-Sectional Study.

Introduction: The internet has become a part of everyday life, and during the COVID-19 pandemic the rate of internet use has raised even higher, which increases the possibility of compulsive and problematic use leading to the acceptance of online misbeliefs and conspiration theories. This cross-sectional study aimed to explore the relationship between COVID-19-related misconceptions and internet addiction among adult recreational online gamers. Methods: A sample of 1671 recreational video game users completed the online survey (male: n = 1522 (91.08%), mean age = 21.83, SD = 4.18; female: n = 149 (8.91%), mean age = 24.33, SD = 8.38). Demographic questions, risk factors and health-related questions, internet use and addiction were measured alongside a short questionnaire about common COVID-19-related topics, such as its origin and risk of infection. Results: Out of all participants 248 (14.8%) answered all the COVID-19-related questions properly, thus having no misconceptions, while 545 (32.6%) had one wrong answer, 532 (31.8%) had 2 wrong answers, 251 (15.0%) had 3 wrong answers, 78 (4.7%) had 4 wrong answers and 17 (1.0%) had 5 wrong answers. Significant factors to a higher number of COVID-misconceptions were time spent studying (χ2 (35,1671) = 63.86, p = 0.002), marital status (χ2 (15,1671) = 30.65 p = 0.01) and secondary employment (χ2 (51,671) = 14.88, p = 0.01). Although 17.1% of the participants reached the threshold score for internet addiction, the predictors of COVID-19 misconceptions were marital status (ß = -0.06, p = 0.01) and time spent studying (ß = 0.05, p = 0.03), while neither daily internet use, internet addiction scores or risk factors predicted these misconceptions in a linear regression model. Discussion: Our study concludes that Internet addiction did not directly influence misconceptions about the COVID-19 pandemic in this population despite the surprisingly high rate of problematic users.

MRI driven magnetic microswimmers.

Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach.

Prevalence and Risk Factors of Problematic Internet Use among Hungarian Adult Recreational Esports Players.

Background: Esports are highly prevalent in modern culture, particularly among young people, and are a healthy hobby for the majority of users. However, there is a possible link between video gaming (including esports) and problematic internet use (so-called internet addiction, IA), mostly involving adolescents. Methods: Here we present an online survey focusing on the prevalence and risk factors of internet addiction among adult esports players. Demographics included age, gender, family type, type of work, working years and daily internet use. Medical conditions associated with IA such as smoking, alcohol and drug intake, hypertension, diabetes, ischemic heart disease, musculoskeletal pain and history of depression were also recorded. Results: Overall, 2313 players including 176 females (7.6%) and 2137 males (92.4%) participated in our online survey. Age distribution was the following: 18−25 years 90.3% (2088/2313), 26−35 years 7.95% (184/2313), 36−45 years 0.86% (20/2313), 46−55 years 0.82% (19/2313), 56−62 years 0.04% (1/2313) and 62 years or older 0.04% (1/2313). Internet addiction was detected in 19.9% of players (461/2313) based on the Problematic Internet Use Questionnaire. In a multivariate analysis internet addiction was significantly associated with age between 18 and 25 (OR: 1.675, p = 0.002), being single (OR = 1.505, p = 0.014), internet use > 6 h daily (OR = 4.338, p < 0.001), having < 3 children (OR: 2.037, p = 0.023) and having secondary employment (OR = 1.789, p = 0.037). Regular alcohol intake (OR = 18.357, p < 0.001) and history of depression (OR= 5.361, p = 0.032) were also strongly correlated with IA. Conclusion: This is the first study from Hungary investigating the prevalence and risk factors of internet addiction among adult esports players. One out of five adult gamers suffered from IA. Our study also draws attention to increased risk within this group and risk factors such as younger age, family status and type of employment.

Internet addiction: the medical challenge of the 21st century? br / Internetfüggoség: a 21. század orvosi kihívása?

As a result of digitalisation and the increasing use of the internet, its problematic use is on the rise in the 21st cen-tury, with a predominant impact on minors and a potentially increasing challenge for health care systems in the fu-ture. The main risk factors for this phenomenon are age, inadequate social and family relationships, and can be as-sociated with mental problems such as depression and anxiety, somatic illnesses, often with additional dependencies. Imaging studies can detect abnormally functioning brain areas in the affected individuals, however, there is a signifi-cant heterogeneity among them. Similar to other addictions, extensive internet use negatively affects the individual in all areas of life. We do not have a high level of evidence for treatment yet, but it appears that treatments used in other (classic) addictive diseases may be effective.

Internet Addiction and Burnout in A Single Hospital: Is There Any Association?

The extensive availability of the internet has led to the recognition of problematic internet use, the so-called Internet Addiction (IA), mostly involving adolescents. Burnout can lead to substance abuse or addictive behaviour (such as internet addiction) as a coping method. There are insufficient data about internet addiction and its possible association with burnout in adults, especially among healthcare workers. The aim of our present study was to focus on prevalence and the risk factors of internet addiction and its possible association with burnout among healthcare workers in a single hospital applying a questionnaire-based survey. In total, 49 doctors (10.1%), 198 nurses (40.9%), 123 medical assistant (25.4%), 73 other healthcare workers (15.1%), and 42 (1.7%) healthcare associated workers (cleaning, laundry, etc.) have completed our survey. In a multivariate analysis, IA was associated with age between 18 and 25 (OR: 2.6, p = 0.024), surfing on the internet >5 h daily (OR 25.583, p < 0.001), being single (OR: 4.275, p = 0.006), being childless (OR: 3.81, p = 0.011), working less than five years (OR 2.135, p = 0.048) and job type (being healthcare associated worker, OR: 2.907, p = 0.009). Illicit drug intake (OR 52.494, p < 0.001), and diabetes (OR: 4.122, p = 0.043) were also significantly associated with internet addiction. No association of burnout and IA could be found. A small but significant proportion of our healthcare workers suffered from IA, which was associated with substance abuse and diabetes in multivariate analysis. Our study also draws attention to the risk factors of IA such as younger age, family status, working type and working hours internet use. The possible association of burnout and IA merits further investigation.

Prevalence and Risk Factors of Internet Addiction among Hungarian High School Teachers.

The extensive availability of internet has led to the the recognition of problematic internet use (so called internet addiction, IA) mostly involving adolescents. There is limited data about the prevalence of IA in adults. Here we present a study focusing on the prevalence and risk factors of internet addiction among high school teachers. Overall 2500 paper-based questionnaires were successfully delivered and 1817 responses received (response rate of 72.7%). In our study 1194 females (65.7%) and 623 males (34.3%) participated. In a multivariate analysis including of all factors (demographic data, internet habits, comorbidity etc.) age <35 years (OR: 6.098, CI: 5.09-7.08, p < 0.001), male gender (OR = 5.413, CI: 4.39-6.18, p = 0.002), surfing on the internet > 5 h daily (OR 2.568, CI: 2.03-3.39, p < 0.001), having no children (OR: 1.353, CI: 1.13-1.99, p = 0.0248), and having secondary employment (OR = 11.377, CI: 8.67-13.07, p = 0.001) were significantly associated with internet addiction. This is the first study from Hungary showing the prevalence and risk factors of internet addiction among high school teachers. A small, but significant proportion suffered from IA. Our study also draws attention to the risk factors of IA such as younger age, family status and working type.

Jump stabilization and landing control by wing-spreading of a locust-inspired jumper.

Bio-inspired robotics is a promising design strategy for mobile robots. Jumping is an energy efficient locomotion gait for traversing difficult terrain. Inspired by the jumping and flying behavior of the desert locust, we have recently developed a miniature jumping robot that can jump over 3.5 m high. However, much like the non-adult locust, it rotates while in the air and lands uncontrollably. Inspired by the winged adult locust, we have added spreading wings and a tail to the jumper. After the robot leaps, at the apex of the trajectory, the wings unfold and it glides to the ground. The advantages of this maneuver are the stabilization of the robot when airborne, the reduction of velocity at landing, the control of the landing angle and the potential to change the robot's orientation and control its flight trajectory. The new upgraded robot is capable of jumping to a still impressive height of 1.7 m eliminating airborne rotation and reducing landing velocity. Here, we analyze the dynamic and aerodynamic models of the robot, discuss the robot's design, and validate its ability to perform a jump-glide in a stable trajectory, land safely and change its orientation while in the air.

Dynamics and stability of directional jumps in the desert locust.

Locusts are known for their ability to jump large distances to avoid predation. The jump also serves to launch the adult locust into the air in order to initiate flight. Various aspects of this important behavior have been studied extensively, from muscle physiology and biomechanics, to the energy storage systems involved in powering the jump, and more. Less well understood are the mechanisms participating in control of the jump trajectory. Here we utilise video monitoring and careful analysis of experimental directional jumps by adult desert locusts, together with dynamic computer simulation, in order to understand how the locusts control the direction and elevation of the jump, the residual angular velocities resulting from the jump and the timing of flapping-flight initiation. Our study confirms and expands early findings regarding the instrumental role of the initial body position and orientation. Both real-jump video analysis and simulations based on our expanded dynamical model demonstrate that the initial body coordinates of position (relative to the hind-legs ground-contact points) are dominant in predicting the jumps' azimuth and elevation angles. We also report a strong linear correlation between the jumps' pitch-angular-velocity and flight initiation timing, such that head downwards rotations lead to earlier wing opening. In addition to offering important insights into the bio-mechanical principles of locust jumping and flight initiation, the findings from this study will be used in designing future prototypes of a bio-inspired miniature jumping robot that will be employed in animal behaviour studies and environmental monitoring applications.

Active catheter driven by a thermo-hydraulic actuation.

Catheters and flexible endoscopes are usually steered by mechanical wires that are driven from their base. Due to friction and buckling there is a need to place the driving actuator of the catheter at the catheter's tip. Such active catheter's manoeuvrability is much higher than wire-driven ones. A problem with active catheters is the difficulty to create high enough bending using micro-actuators placed at the catheter's tip. Our actuation method is an attempt to overcome this difficulty by using a novel thermo-hydraulic actuation method. The magnitude of the bending torque of our actuator is created by internal hydraulic pressure in the tube and the steering direction is controlled by the thermal micro-actuator embedded in the wall of the tube. In this paper we present the modelling, optimization, design and testing of an initial prototype of such an actuator. We found that a 4 mm OD actuator made of TPU can bend to ±12°.

Numerical analysis of the hemodynamics of an abdominal aortic aneurysm repaired using the endovascular chimney technique.

This paper presents a numerical analysis of the hemodynamics in an abdominal aorta (AA) with an aneurysm repaired by a stent graft (SG) system using the chimney technique. Computational fluid dynamics (CFD) simulations were conducted in a model of an AA repaired with a chimney stent graft (CSG) inserted into a renal artery parallel to an aortic SG and a model of a healthy AA. Comparing the simulation results of these two cases suggests that the presence of the CSG in the AA causes changes in average wall shear stress (WSS), potentially damaging recirculation zones, and additional changes in flow patterns.

Thermal expansion imaging for monitoring lesion depth using M-mode ultrasound during cardiac RF ablation: in vitro study.

PURPOSE: We demonstrate a novel method for automatic direct lesion depth (LD) tracking during coagulation from time series of a single A-mode ultrasound (US) transducer custom fit at the tip of a RFA catheter. This method is named thermal expansion imaging (TEI). METHODS: A total of 35 porcine myocardium samples were ablated (LD 0.5-5 mm) while acquiring US, electrical impedance (EI) and contact force (CF) data. US images are generated in real time in terms of echo intensity (M-mode) and phase (TEI). For TEI, displacements between US time series are estimated with time-domain cross-correlation. A modified least squares strain estimation with temporal and depth smoothing reveals a thermal expansion boundary (TEB)--negative zero-crossing of temporal strain--which is associated to the coagulated tissue front. RESULTS: M-mode does not reliably delineate RFA lesions. TEI images reveal a traceable TEB with RMSE = 0.50 mm and R2 = 0.85 with respect to visual observations. The conventional technique, EI, shows lower R2 = 0.7 and > 200 % variations with CF. The discontinuous time progression of the TEB is qualitatively associated to tissue heterogeneity and CF variations, which are directly traceable with TEI. The speed of sound, measured in function of tissue temperature, increases up to a plateau at 55°C , which does not explain the observed strain bands in the TEB. CONCLUSIONS: TEI successfully tracks LD in in vitro experiments based on a single US transducer and is robust to catheter/tissue contact, ablation time and even tissue heterogeneity. The presence of a TEB suggests thermal expansion as the main strain mechanism during coagulation, accompanied by compression of the adjacent non-ablated tissue. The isolation of thermally induced displacements from in vivo motion is a matter of future research. TEI is potentially applicable to other treatments such as percutaneous RFA of liver and high-intensity focused ultrasound.

A locust-inspired miniature jumping robot.

Unmanned ground vehicles are mostly wheeled, tracked, or legged. These locomotion mechanisms have a limited ability to traverse rough terrain and obstacles that are higher than the robot's center of mass. In order to improve the mobility of small robots it is necessary to expand the variety of their motion gaits. Jumping is one of nature's solutions to the challenge of mobility in difficult terrain. The desert locust is the model for the presented bio-inspired design of a jumping mechanism for a small mobile robot. The basic mechanism is similar to that of the semilunar process in the hind legs of the locust, and is based on the cocking of a torsional spring by wrapping a tendon-like wire around the shaft of a miniature motor. In this study we present the jumping mechanism design, and the manufacturing and performance analysis of two demonstrator prototypes. The most advanced jumping robot demonstrator is power autonomous, weighs 23 gr, and is capable of jumping to a height of 3.35 m, covering a distance of 1.37 m.