Kinematic optimization for the design of a collaborative robot end-effector for tele-echography

Tele-examination based on robotic technologies is a promising solution to solve the current worsening shortage of physicians. Echocardiography is among the examinations that would benefit more from robotic solutions. However, most of the state-of-the-art solutions are based on the development of specific robotic arms, instead of exploiting COTS (commercial-off-the-shelf) arms to reduce costs and make such systems affordable. In this paper, we address this problem by studying the design of an end-effector for tele-echography to be mounted on two popular and low-cost collaborative robots, i.e., the Universal Robot UR5, and the Franka Emika Panda. In the case of the UR5 robot, we investigate the possibility of adding a seventh rotational degree of freedom. The design is obtained by kinematic optimization, in which a manipulability measure is an objective function. The optimization domain includes the position of the patient with regards to the robot base and the pose of the end-effector frame. Constraints include the full coverage of the examination area, the possibility to orient the probe correctly, have the base of the robot far enough from the patient’s head, and a suitable distance from singularities. The results show that adding a degree of freedom improves manipulability by 65% and that adding a custom-designed actuated joint is better than adopting a native seven-degrees-freedom robot

Identification of gait phases with neural networks for smooth transparent control of a lower limb exoskeleton

Lower limbs exoskeletons provide assistance during standing, squatting, and walking. Gait dynamics, in particular, implies a change in the configuration of the device in terms of contact points, actuation, and system dynamics in general. In order to provide a comfortable experience and maximize performance, the exoskeleton should be controlled smoothly and in a transparent way, which means respectively, minimizing the interaction forces with the user and jerky behavior due to transitions between different configurations. A previous study showed that a smooth control of the exoskeleton can be achieved using a gait phase segmentation based on joint kinematics. Such a segmentation system can be implemented as linear regression and should be personalized for the user after a calibration procedure. In this work, a nonlinear segmentation function based on neural networks is implemented and compared with linear regression. An on-line implementation is then proposed and tested with a subject

Numerical Simulation of a Capillary Pulsating Heat Pipe in Various Gravity Conditions

In the last two decades a new concept of capillary heat pipe without wick structures, commonly known as Pulsating Heat Pipe (PHP), entered the domain of the two-phase passive heat transfer devices. The thermal-hydraulic behavior of this mini-channel with alternate heating and cooling zones, evacuated and partially filled with a working fluid, mainly depends on the interplay between phase change phenomena, capillary and gravity, if present, which may assist or damp the fluid motion. Numerous are the attempts to simulate PHPs complex behavior, but only a few of them are capable of complete thermal-hydraulic simulations; in addition, none is able to predict the effects of various gravity levels. Nevertheless, validated numerical simulations can constitute useful tools to complete and support experimental studies, and to help the design of new and better performing PHPs. Thus, a novel lumped parameters numerical code for the transient thermo-hydraulic simulation of PHPs has been developed and validated. It consists of a two-phase separated flow model where capillary slug flow is assumed a priori. A complete set of balance differential equations accounts for homogeneous and heterogeneous phase-changes, as well as thermal and fluid-dynamic phenomena. This novel model shows a very good quantitative and qualitative prediction capability not only when computing the correct measured equivalent thermal resistance, but even when reproducing the experimental trend of temperature when transient conditions are applied. This paper presents the comparison between numerical and experimental data, for a copper PHP (I.D./O.D. 1.1mm/2.0mm) filled with FC-72 tested experimentally in micro-gravity (58th Parabolic Flight Campaign), and hyper-gravity conditions (ESA SYT!2013 Programme

PIK3CA-Related Overgrowth Spectrum From Diagnosis to Targeted Therapy: A Case of CLOVES Syndrome Treated With Alpelisib

PIK3CA-related overgrowth spectrum (PROS) is an umbrella term referring to various clinical entities, which share the same pathogenetic mechanism. These conditions are caused by somatic gain-of-function mutations in PIK3CA, which encodes the 110-kD catalytic α subunit of PI3K (p110α). These PIK3CA mutations occur as post-zygotic events and lead to a gain of function of PI3K, with consequent constitutional activation of the downstream cascades (e.g., AKT/mTOR pathway), involved in cellular proliferation, survival and growth, as well as in vascular development in the embryonic stage. PIK3CA-related cancers and PROS share almost the same PIK3CA mutational profile, with about 80% of mutations occurring at three hotspots, E542, E545, and H1047. These hotspot mutations show the most potent effect on enzymatic activation of PI3K and consequent downstream biological responses. If present at the germinal level, these gain-of-function mutations would be lethal to the embryo, therefore we only see them in the mosaic state. The common clinical denominator of PROS disorders is that they are sporadic conditions, presenting with congenital or early childhood onset overgrowth with a typical mosaic distribution. However, the severity of PROS is highly variable, ranging from localized and apparently isolate overgrowth to progressive and extensive lipomatous overgrowth associated with life-threatening vascular malformations, as seen in CLOVES syndrome. Traditional therapeutic approaches, such as sclerotherapy and surgical debulking, are often not curative in PROS patients, leading to a recrudescence of the overgrowth in the treated area. Specific attention has been recently paid to molecules that are used and studied in the oncogenic setting and that are targeted on specific alterations of the pathway PI3K/AKT/mTOR. In June 2018, Venot et al. showed the effect of Alpelisib (BYL719), a specific inhibitor for the p110α subunit of PI3K, in patients with PROS disorders who had severe or life-threatening complications and were not sensitive to any other treatment. In these cases, dramatic anatomical and functional improvements occurred in all patients across many types of affected organ. Molecular testing in PROS patients is a crucial step in providing the conclusive diagnosis and then the opportunity for tailored therapy. The somatic nature of this group of diseases makes challenging to reach a molecular diagnosis, requiring deep sequencing methods that have to be performed on DNA extracted from affected tissue. Moreover, even analyzing the DNA extracted from affected tissue there is no guarantee to succeed in detection of the casual somatic mutation, since the affected tissue itself is highly heterogeneous and biopsy approaches can be burdened by incorrect sampling or inadequate tissue sample. We present an 8-year-old girl with CLOVES syndrome, born with a large cystic lymphangioma involving the left hemithorax and flank, multiple lipomas, and hypertrophy of the left foot and leg. She developed severe scoliosis. Many therapeutic approaches have been attempted, including Sildenafil treatment, scleroembolization, laser therapy, and multiple debulking surgeries, but none of these were of benefit to our patient's clinical status. She then started treatment with Rapamycin from May 2019, without significant improvement in both vascular malformation and leg hypertrophy. A high-coverage Whole Exome Sequencing analysis performed on DNA extracted from a skin sample showed a mosaic gain-of-function variant in the PIK3CA gene (p.H1047R, 11% of variant allele frequency). Once molecular confirmation of our clinical suspicion was obtained, after a multidisciplinary evaluation, we decided to discontinue Sirolimus and start targeted therapy with Alpelisib (50 mg/day). We noticed a decrease in fibroadipose overgrowth at the dorsal level, an improvement in in posture and excellent tolerability. The treatment is still ongoing

A Bioinspired Plasmonic Nanocomposite Actuator Sunlight-Driven by a Photothermal-Hygroscopic Effect for Sustainable Soft Robotics

Combined photothermal-hygroscopic effects enable novel materials actuation strategies based on renewable and sustainable energy sources such as sunlight. Plasmonic nanoparticles have gained considerable interest as photothermal agents, however, the employment in sunlight-driven photothermal-hygroscopic actuators is still bounded, mainly due to the limited absorbance once integrated into nanocomposite actuators and the restricted plasmonic peaks amplitude (compared to the solar spectrum). Herein, the design and fabrication of an AgNPs-based plasmonic photothermal-hygroscopic actuator integrated with printed cellulose tracks are reported (bioinspired to Geraniaceae seeds structures). The nanocomposite is actuated by sunlight power density (i.e., 1 Sun = 100 mW cm−2). The plasmonic AgNPs are in situ synthesized on the PDMS surface through a one-step and efficient fluoride-assisted synthesis (surface coverage ≈40%). The nanocomposite has a broadband absorbance in the VIS range (>1) and a Photothermal Conversion Efficiency ≈40%. The actuator is designed exploiting a mechanical model that predicted the curvature and forces, featuring a ≈6.8 ± 0.3 s response time, associated with a ≈43% change in curvature and a 0.76 ± 0.02 mN force under 1 Sun irradiation. The plasmonic nanocomposite actuator can be used for multiple tasks, as hinted through illustrative soft robotics demonstrators, thus fostering a bioinspired approach to developing embodied energy systems driven by sunlight

Ultraconformable, Self‐Adhering Surface Electrodes for Measuring Electrical Signals in Plants

The electrical signals in plant's physiological processes are of great interest in biology, biohybrid robotics, and sensors for interfacing the living organisms with an electronic readout and control. This paper reports on the application of conformable, self-adhering surface electrodes for the measurement and bidirectional stimulation of electrical signals in plants. The inkjet-printed poly(3,4-ethylenedioxythiophene) polystyrene sulfonate based electrodes are <3 µm thick, light-weight, soft and flexible, and can be easily and non-invasively transferred onto plant's outer organs for surface potential recordings due to their realization on tattoo transfer paper. The devices prove to be extremely versatile for analyzing electrical signals in Dionaea muscipula, Arabidopsis thaliana, and Codariocalyx motorius and for stimulating mechanical responses in D. muscipula. A benefit over traditional electrodes is the van der Waals self-adherence of the thin electrodes, their intrinsic flexibility and adaptation also on small leaves while providing excellent readout. The same electrode allows long-term multicycle measurements over at least 10 days and, moreover, straightforward recordings on fast-moving organs such as snapping fly traps and endogenously oscillating leaflets. The results confirm that self-adhering soft organic electronics are particularly suitable for plant electrical signal analysis when easy-application, self-adaptation, and long-term performance are required in plant science, biohybrid robotics, and biohybrid sensors