conceptual design and control strategy of a robotic cell for precision assembly in radar antenna systems

Abstract Dip-Brazing is a metal-joining process in which two or more metal items are joined together using a low-temperature melting element as filler. In telecommunication field, this process is used to fabricate radar antenna systems. The process begins with the assembly of the parts constituting the antenna and the thin filler sheet used to join the parts. The mechanical deformations of the micro-pins of the parts allow to obtain a more compact mechanical assembly, before than the antenna system is subjected to an immersion cycle used for adjoining the parts. In this work, we present the design of the robotic cell to automate the assembly procedure in the aluminum dip-brazing of antenna in MBDA missile systems. In particular, we propose a robotic cell using two stations: i) assembly, using a SCARA manipulator; ii) riveting, using a three-axis cartesian robot designed for positioning a radial riveting unit. Motion control of the robots and scheduling of the operations is presented. Experiments simulated in a virtual environment show an almost perfect tracking of the designed trajectories. The standardization of the procedure as well as the reduction of its execution time is thus achieved for the industrial scenario

Leukocytospermia and sperm preparation - a flow cytometric study

Reprod Biol Endocrinol. 2009 Nov 19;7:12

Enhanced tonic GABAA inhibition in typical absence epilepsy

The cellular mechanisms underlying typical absence seizures, which characterize various idiopathic generalized epilepsies, are not fully understood, but impaired GABAergic inhibition remains an attractive hypothesis. In contrast, we show here that extrasynaptic GABAA receptor–dependent ‘tonic’ inhibition is increased in thalamocortical neurons from diverse genetic and pharmacological models of absence seizures. Increased tonic inhibition is due to compromised GABA uptake by the GABA transporter GAT–1 in the genetic models tested, and GAT–1 is critical in governing seizure genesis. Extrasynaptic GABAA receptors are a requirement for seizures in two of the best characterized models of absence epilepsy, and the selective activation of thalamic extrasynaptic GABAA receptors is sufficient to elicit both electrographic and behavioural correlates of seizures in normal animals. These results identify an apparently common cellular pathology in typical absence seizures that may have epileptogenic significance, and highlight novel therapeutic targets for the treatment of absence epilepsy.peer-reviewe

X-linked congenital ataxia: A clinical and genetic study

International audienceWe report on a family in which two males are affected with X-linked congenital ataxia (XCA). Clinical manifestations include severe hypotonia at birth, delay of early motor development, slow eye movements, and nonprogressive cerebellar ataxia. The neurological examination excluded a neuromuscular disease, mental retardation, and pyramidal tract involvement. Neuroimaging showed global cerebellar atrophy in both patients that was not evident in the first years of life. The clinical findings in this family are very similar to those in a Russian pedigree [Illarioskin et al., 1996: Ann Neurol 40:75-83] and outline a recognizable phenotype. Linkage studies in our family, using 28 highly polymorphic Généthon microsatellite markers evenly distributed along the X chromosome, excluded a 24 cM interval between DXS990 and DXS424 located within the previous candidate region of 54 cM, reducing the critical interval

Magnetic resonance imaging differential diagnosis of brainstem lesions in children

Differential diagnosis of brainstem lesions, either isolated or in association with cerebellar and supra-tentorial lesions, can be challenging. Knowledge of the structural organization is crucial for the differential diagnosis and establishment of prognosis of pathologies with involvement of the brainstem. Familiarity with the location of the lesions in the brainstem is essential, especially in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive and specific imaging technique for diagnosing disorders of the posterior fossa and, particularly, the brainstem. High magnetic static field MRI allows detailed visualization of the morphology, signal intensity and metabolic content of the brainstem nuclei, together with visualization of the normal development and myelination. In this pictorial essay we review the brainstem pathology in pediatric patients and consider the MR imaging patterns that may help the radiologist to differentiate among vascular, toxico-metabolic, infective-inflammatory, degenerative and neoplastic processes. Helpful MR tips can guide the differential diagnosis: These include the location and morphology of lesions, the brainstem vascularization territories, gray and white matter distribution and tissue selective vulnerability