Prostate biopsies assisted by comanipulated probe-holder: first in man

International audiencePurpose: a comanipulator for assisting endorectal prostate biopsies is evaluated through a first-in man clinical trial. This lightweight system, based on conventional robotic components, possesses 6 degrees of freedom. It uses 3 electric motors and 3 brakes. It features a free mode, where its low friction and inertia allow for natural manipulation of the probe and a locked mode, exhibiting both a very low stiffness and a high steady state precision. Methods: Clinical trials focusing on the free mode and the locked mode of the robot are presented. The objective is to evaluate the practical usability and performance of the robot during clinical procedures. A research protocol for a prospective randomized clinical trial has been designed. Its specific goal is to compare the accuracy of biopsies performed with and without the assistance of the comanipulator. Results:The accuracy is compared between biopsies performed with and without the assistance of the comanipulator, across the 10 first patients included in the trial. Results show a statistically significant increase of the precision.. This work is partially funded french state funds managed by the ANR within the Investissements d'Avenir programme (Labex CAMI) under reference ANR-11-LABX-0004. 2 Marie-Aude Vitrani et al

Robotic Cane Controlled to Adapt Automatically to Its User Gait Characteristics.

Research on robotic assistance devices tries to minimize the risk of falls due to misuse of non-actuated canes. This paper contributes to this research effort by presenting a novel control strategy of a robotic cane that adapts automatically to its user gait characteristics. We verified the proposed control law on a robotic cane sharing the main shape features of a non-actuated cane. It consists of a motorized telescopic shaft mounted on the top of two actuated wheels driven by the same motor. Cane control relies on two Inertial Measurement Units (IMU). One is attached to the cane and the other to the thigh of its user impaired leg. During the swing phase of this leg, the motor of the wheels is controlled to enable the tracking of the impaired leg thigh angle by the cane orientation. The wheels are immobilized during the stance phase to provide motionless mechanical support to the user. The shaft length is continuously adjusted to keep a constant height of the cane handle. The primary goal of this work is to show the feasibility of the cane motion synchronization with its user gait. The control strategy looks promising after several experiments. After further investigations and experiments with end-users, the proposed control law could pave the road toward its use in robotic canes used either as permanent assistance or during rehabilitation.Project i-Gait, under reference ANR-16-CE33-0012

Heterogenous within-herd seroprevalence against epizootic hemorrhagic disease virus type 8 (EHDV-8) after massive virus circulation in cattle in France, 2023

Background and objectivesThe emergence of Epizootic Hemorrhagic Disease Virus-8 (EHDV-8) in mainland France in 2023 led to thousands of clinical outbreaks in cattle herds and likely led to the natural immunization of a large number of animals. However, uncertainties persist regarding the extent of this immunity, both within herds and across affected regions. This study therefore aimed at investigating the variability of within-herd seroprevalence in clinically affected and non-affected herds across geographical areas with differing levels of disease incidence.MethodologyA study was launched in February 2024 to assess the variability of within-herd seroprevalence in three geographical areas with varying EHDV-8 clinical incidence. A total of 2,763 serums samples from cattle over 24 months in 30 herds with clinical outbreaks and 31 herds without reported clinical case were analyzed using a commercial competitive ELISA.ResultsA strong south–north seroprevalence gradient was observed, with the highest animal-level seroprevalence evidenced in the southernmost zone (Pyrenean Piémont) (82.6%, CI 95%: 81.1–83.9), which also experienced the highest incidence of clinical outbreaks. In contrast, significantly lower seroprevalence levels were found in the more northern areas: (zone 2: 11.6, 95% CI: 10.7–12.7; zone 3: 0.3, 95% CI: 0.1–1.1), where clinical outbreaks were less frequent. The within-herd seroprevalence varied widely among herds but was significantly higher in those located in the southernmost zone, compared to other areas. Within each zone, no significant differences in seroprevalence were observed between clinical outbreak herds and non-outbreak herds.DiscussionThis study highlights significant geographic and between herd variability in seroprevalence against EHDV-8 after the major virus circulation experienced in 2023, and provides critical insights into regional risks and the potential impact of future EHDV-8 circulation

Diversified actin protrusions promote environmental exploration but are dispensable for locomotion of leukocytes

Most migrating cells extrude their front by the force of actin polymerization. Polymerization requires an initial nucleation step, which is mediated by factors establishing either parallel filaments in the case of filopodia or branched filaments that form the branched lamellipodial network. Branches are considered essential for regular cell motility and are initiated by the Arp2/3 complex, which in turn is activated by nucleation-promoting factors of the WASP and WAVE families. Here we employed rapid amoeboid crawling leukocytes and found that deletion of the WAVE complex eliminated actin branching and thus lamellipodia formation. The cells were left with parallel filaments at the leading edge, which translated, depending on the differentiation status of the cell, into a unipolar pointed cell shape or cells with multiple filopodia. Remarkably, unipolar cells migrated with increased speed and enormous directional persistence, while they were unable to turn towards chemotactic gradients. Cells with multiple filopodia retained chemotactic activity but their migration was progressively impaired with increasing geometrical complexity of the extracellular environment. These findings establish that diversified leading edge protrusions serve as explorative structures while they slow down actual locomotion

An Ungrounded Master Device for Tele-Microassembly

International audienceMicro-assembly is a challenging issue for automation due to particularities of micro-world physics and limitations on sensors. Consequently, most applications are humanoperated often with basic joystick-like interfaces. Beside being nonintuitive, these solutions do not provide their users with a meaningful insight of the microworld. This paper proposes a novel intuitive remote handling interface, using a classical hand-held assembly tool as a paradigm. The master device is a portable instrumented tweezers with an active DoF. Its spatial motion, tracked by optical means, controls the slave kinematics while its pinch commands the slave robot's microgripper and provides haptic feedback. Different coupling strategies using position or speed variables are demonstrated

A Handheld Master Device for 3D Remote Micro-Manipulation

International audienceMicro-assembly has always been a substantial issue for automation: micro-objects are difficult to grasp due to micro-world physical laws and a lack of adapted sensors. Therefore, many tasks are teleoperated using a nonintuitive device as joystick or button. This paper proposes a fresh remote handling solution to fill that need. A new 1-DOF master device which mimics a tweezers is brought to the fore: it is an instrumented haptic tweezers, handheld, allowing a high intuitiveness for the user. This master device, coupled with a tracking system, controls a micro-positioner and a micro-gripper. Different coupling strategies using position or speed variables are demonstrated

Precisely positioning the tip of an instrument inserted through an orifice with a free wrist robot: application to prostate biopsies

International audiencePurpose Robots with a spherical unactuated wrist can be used for minimally invasive surgery. With such a robot, positioning the wrist center controls the instrument tip position when assuming that the insertion site behaves like a lever with a fixed and known fulcrum. In practice, this assumption is not always respected. In this paper we first study the practical consequences of this problem in terms of tip precision positioning. We then propose a robotic control scheme that improves the precision compared to the fixed point assumption approach. Methods In the first part of the paper, data recorded during robot-assisted transrectal needle positioning for prostate biopsies (nine patients) are exploited to quantify the positioning error induced by the use of a fixed point hypothesis in the positioning process. In the second part of the paper advanced control techniques allow for the online identification of a locally linear system that describes a model characterized by anisotropy and center displacement. A laboratory apparatus is used to demonstrate the resulting improvement on tip positioning precision. Results Errors obtained by processing the clinical data reach 7.5 mm at the tip in average. Errors obtained with the laboratory apparatus drop from 2.4 mm in average to 0.8 mm when using real-time model update