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Development of a 6-Degrees-of-Freedom Hybrid Interface Intended for Teleoperated Robotic Cervical Spine Surgery
No full textInternational audienceThis article deals with the development of a 6-degrees-of-freedom (DoF) hybrid interface for a teleoperated robotic platform intended to assist surgeons in cervical spine surgery. The targeted task is the drilling of cervical vertebrae for the attachment of spinal implants. Given the complex anatomy of the cervical region, with the proximity of the spinal cord and vertebral arteries, high accuracy in the drilling procedure is required to avoid complications for the patient. In this context, the proposed hybrid interface has been designed to meet the requirements of the drilling task, in terms of degrees of freedom, workspace, and force feedback, which have been identified through a literature review. It consists of an association of two parallel mechanisms and a centrally located serial mechanism. Direct and inverse kinematic modeling of each mechanism and one of the complete interfaces were carried out. A study of the dexterity distribution of the parallel mechanisms was carried out to select the suitable interface working mode that would keep the singularities away from the prescribed workspace. In addition, the force feedback was implemented in static mode, neglecting in the first time the weight of the system. The interface design parameters were then optimized to avoid singularities within the prescribed workspace, to minimize motor torques, and to reduce the size of the interface. These development stages led to the design of a motorized prototype of the hybrid interface
Une histoire de « crocs-en-jambe » ? Le doctorat comme enjeu de luttes dans le processus d’institutionnalisation de la science politique en France
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In-service teachers' perceptions of board games in teaching: Impact of the level of seriousness of the games and teachers' characteristics
No full textInternational audienceBoard games have become popular for teaching practices. Yet, factors of teachers' acceptance of board games remain unknown. In the present mixed-method cross-sectional survey study, 255 in-service French teachers were surveyed to examine the impact commercial-off-the-shelves and serious of board games, prior gaming experience, norms, and attitudes. Findings showed that teachers perceived more opportunities to learn for serious than for commercial-off-the-shelf board games. Attitudes had a positive impact on all variables and exerted a stronger impact than norms. Prior personal and professional gaming experience affected differently teachers' acceptance of board games. Educational implications for teachers' training programs are discussed
Gas radiation effect on a turbulent thermal plume in a confined cavity using direct numerical simulation
No full textInfluence of gas radiation on a thermal plume is investigated in a cubical cavity filled with humid air (air/H2O mixture) by means of Direct Numerical Simulation. In this work, radiation within the fluid is considered by the SLW model developed by Denison and Webb and numerically solved using the Discrete Ordinate Method (S 8 quadrature). The simulations are conducted for humid air with different amounts of water vapor and compared to the case without radiation. Two values of the Rayleigh numbers, 2 10 6 and 10 9, are considered, corresponding to steady and turbulent flow regimes. Steady solutions show that gas radiation tends to reduce the spatial spreading of the thermal plume and to homogenize the temperature field away from the heat source. Gas radiation also results in an attenuation of the global circulation. It is shown that the radiative fluxes are much higher than convective fluxes on the isothermal walls, and the radiative heat transfer still increases with the water vapor concentration. For the turbulent regime, accounting for radiation leads to a less fluctuating behavior of the plume and induces a global shift of the mean temperature field in most of the cavity, except in the region around the heat source. Regarding the mean flow field, thermal radiation tends to weaken the intensity of flow circulation, but to accelerate the flow velocity along the centerline above the heat source
The contribution of addictovigilance data to the French medical cannabis experimentation
No full textInternational audienceIn France, cannabis is the most widely used illicit psychoactive substance. Recently, a new market for cannabidiol (CBD) products has emerged called “cannabis light” or “cannabis well-being”. In parallel, the experimentation of medical cannabis began on March 26, 2021, for specific indications. Some clinical effects of cannabis have been put forward for medical purposes; however, these are counterbalanced by adverse events (AEs). Data from addictovigilance and international literature on the risks associated with non-medical cannabis use have helped establish exclusion criteria for patients at risk of complications when using medical cannabis (such as those with psychotic disorders, severe cardiovascular, renal, or liver conditions). This also enables the early identification of AEs. Cannabis-based medications are composed of cannabidiol (CBD) and/or delta-9-tetrahydrocannabinol (THC) in varying concentrations. We aimed to present the contribution of the addictovigilance data regarding cannabis-related reports to the ongoing French experimentation on cannabis used for medical purposes, to anticipate potential adverse drug reactions in the treated patients. Among the 3164 patients included in the French experimentation, 1186 of them presented at least one AE. Some of the AEs reported in addictovigilance surveys on non-medical cannabis and CBD were observed during the experimentation of medical cannabis such as cardiovascular AEs (myocardial infarction, strokes, transient ischemic attack), psychiatric AEs (suicidal idea and attempt, depression), worsening of epilepsy, cognitive and/or sedative disorders. Given the potential for pharmacodependence of cannabis medications, it seems important for clinicians to gather the addiction history of their patients (past or present), particularly the use of non-medical cannabis (illicit) and non-medical CBD, to prevent and early detect any risk of abuse. The generalization of the use of medical cannabis was adopted and defined in the 2024 Social Security Financing Act. These medications will be accessible to patients by medical prescription for defined indications. Addictovigilance as well as pharmacovigilance monitoring is crucial in this context of continuing to make medical cannabis available in France. Adverse effects of interest will need to be monitored in particular, including neurological disorders (epilepsy exacerbation, cognitive disorders), psychiatric disorders (substance use disorder, suicidal behaviour), and cardiovascular disorders as well as any unexpected AEs. Close addictovigilance monitoring contributes to increasing the awareness of professionals involved in the clinical management of patients treated with medical cannabis
Parcours polyamoureux. Quand la non-monogamie consensuelle déplace les normes du couple
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Assessment of in vitro efficacy of three-antibiotics combinations against Mycobacterium abscessus
No full textInternational audienceBackground: Mycobacterium abscessus (Mabs) is an environmental bacterium that causes lung infections, especially in patients with cystic fibrosis. Moreover, Mabs exhibits resistance to many antibiotics including anti-tuberculous drugs. Treatment consists of prolonged courses of antibiotic combinations including different molecules. However, its antibiotic resistance coupled with the absence of treatment guidelines leads to high treatment failure. This necessitates the refinement of existing combination therapies to improve patient treatment. This study evaluates the in vitro efficacy of new three-antibiotics combinations from six molecules frequently used in the treatment of Mabs infections: amikacin (AMK), azithromycin (AZM), bedaquiline (BDQ), imipenem (IMI), linezolid (LZD), tigecycline (TIG).Methods: All experiments were performed on the reference strain (ATCC 19977) in 7H9 broth medium at 37 °C and read after 3 days. Based on the efficacy of two-antibiotics combination, efficacy of eleven three-antibiotics including AZM or AMK was studied. 8 concentrations were tested per antibiotic for all three-antibiotics combinations (8*8*8 triplet of concentrations per combination). These combinations were evaluated by calcuting FICimin and by isobolographic analysis.Results: All three-antibiotics combinations tested were synergistic with a FICimin<0,75 as defined previously (Bhusal et al., 2005). Among the three-antibiotics combinations tested, 3-D isobolographic analysis revealed that AZM-LZD combined with either BDQ, IMI or TIG have shown the greatest synergies, as these combinations had the most data points below the 0.5 isobole (Figure 1). The other combinations showed only few or no data point below the 0.5 isobole.Conclusions Comparing the activity of three-antibiotics showed that among the six molecules tested in combination, the three-antibiotics combinations containing AZM-LZD with either BDQ, IMI or TIG were promising and will be further investigated.</b
Enjeu méthodologique de la comparaison pour une recherche en didactique de la littérature : l'exemple de l'oral de la réception au cycle 2
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Electrophysiological characterisation of intranigral-grafted hiPSC-derived dopaminergic neurons in a mouse model of Parkinson’s disease
No full textInternational audienceBackground: Parkinson's disease (PD) is a complex neurological disorder characterized by the progressive degeneration of midbrain dopaminergic (mDA) neurons in the substantia nigra (SN). This degeneration disrupts the basal ganglia loops, leading to both motor and non-motor dysfunctions. Cell therapy for PD aims to replace lost mDA neurons to restore the DA neurotransmission in the denervated forebrain targets. In clinical trials for PD, mDA neurons are implanted into the target area, the striatum, and not in the SN where they are normally located. This ectopic localisation of cells may affect the functionality of transplanted neurons due to the absence of appropriate host afferent regulation. We recently demonstrated that human induced pluripotent stem cells (hiPSCs) derived mDA progenitors grafted into the substantia nigra pars compacta (SNpc) in a mouse model of PD, differentiated into mature mDA neurons, restored the degenerated nigrostriatal pathway, and induced motor recovery. The objective of the present study was to evaluate the long-term functionality of these intranigral-grafted mDA neurons by assessing their electrophysiological properties.Methods: We performed intranigral transplantation of hiPSC-derived mDA progenitors in a 6-hydroxydopamine RAG2-KO mouse model of PD. We recorded in vivo unit extracellular activity of grafted mDA neurons in anesthetised mice from 9 to 12 months post-transplantation. Their electrophysiological properties, including firing rates, patterns and spike characteristics, were analysed and compared with those of native nigral dopaminergic neurons from control mice.Results: We demonstrated that these grafted mDA neurons exhibited functional characteristics similar to those of native nigral dopaminergic neurons, such as large bi-or triphasic spike waveforms, low firing rates, pacemakerlike properties, and two single-spike firing patterns. Although grafted mDA neurons also displayed low discharge frequencies below 10 Hz, their mean frequency was significantly lower than that of nigral mDA neurons, with a differential pattern distribution.Conclusions: Our findings indicate that grafted mDA neurons exhibit dopaminergic-like functional properties, including intrinsic membrane potential oscillations leading to regular firing patterns. Additionally, they demonstrated irregular and burst firing patterns, suggesting they receive modulatory inputs. However, grafted mDA neurons displayed distinct properties, potentially related to their human origin or the incomplete maturation one year after transplantation