Coexistence of mastoid, frontal and vertebral hemangiomas in a patient with diabetic neuropathy: Possible correlation between diabetic angiopathy and intraosseous neoangiogenesis

: Bony hemangiomas are benign vascular lesions with an expansive growth; usually they tend to obliterate the entire bony cavity. They are typical lesion of the spinal bones, but they can rarely arise within other bones of the neurocranium. Diabetic microangiopathy is a condition characterized by the development of aberrant vessel tangles anastomosed to each other due to dysregulated neoangiogenesis. We report the case of a 56-year-old woman, suffering from type 2 diabetes mellitus, admitted to the neurology department due to a reported worsening of paresthesias and dysesthesias of the upper and lower limbs. She performed a contrast-enhanced brain CT scan that showed the presence, at the level of the right mastoid process, of an hypervascular angioma. A subsequent MRI study of the brain and spine showed the presence of multiple bone angiomas, at the level of the right frontal theca and C7, Th3, and Th7 vertebral bodies. Due to the absence of further symptoms and clinical and radiological signs of intracranial compression, the patient did not perform surgery. A radiological follow-up was advised. Although possible pathophysiological correlations between diabetes and vertebral hemangiomas are mentioned in literature, vascular lesions of this type involving vertebrae and skull base simultaneously can be discovered in a patient with chronic diabetic disease. As long as these lesions remain asymptomatic, surgical treatment is not indicated, and the patient is followed over time with radiological follow-up

Peripheral facial palsy following ventriculoperitoneal shunt. The lesson we have learned

The most frequent complications after shunt surgery are infective and obstructive. Other types are less common, and eventually occur due to technical errors during brain ventricular puncture, opening the intraperitoneal cavity or the tunnelling of the catheter between the two points. Although rare, there are well-reported complications related to the poor positioning of the distal catheter, with perforation of organs and tissues.We report a very rare case of a male patient with normal pressure hydrocephalus submitted to ventriculoperitoneal shunt. During tunnelling of the shunt stylet, a peripheral facial palsy due to injury to the extra cranial segment of the facial nerve occurred.To the best of our knowledge this is the second case described in Literature.The patient and the surgeon should be aware of this very rare but possible complication in shunt surgery being careful to the course of the facial nerve in the mastoid region. Keywords: Normal pressure hydrocephalus, Ventriculoperitoneal shunt complications, Facial nerve paralysi

A Numerical Model for the Analysis of the Locomotion of a Cownose Ray

Among all aquatic species, mantas and rays swim by flapping their pectoral fins; this motion is similar to other fishes in terms of efficiency, but it gives better maneuverability and agility in turning. The fin's motion is featured by a traveling wave going opposite to the forward motion, producing a force thanks to momentum conservation. This article aims at understanding the swimming dynamics of rays, focusing on energy efficiency. A computational fluid dynamics (CFD) model of the swimming motion of a cownose ray has been implemented in openfoam, simulating the acceleration of the fish from still to the steady-state velocity using an overset mesh. In this analysis, the one degree-of-freedom dynamics of forward swimming is solved together with the fluid velocity and pressure. The effect of frequency and wavelength of fin motion on thrust, power, and velocity has been investigated and an analysis of the vortices in the wake showed has been performed. The energy efficiency of a self-propelled body has been defined in a novel way and it has been calculated for different motion conditions. The results showed that batoid fishes swim with high energy efficiency and that they are a promising source of inspiration for biomimetic autonomous underwater vehicles

Biomimetic design of an underwater robot inspired to the cownose ray

This paper shows the design of an underwater autonomous robot. The challenges of this activity are mainly linked to motion design and to energy efficiency. Therefore, a bioinspired approach has been used. Batoid fishes swim moving their pectoral fins, they produce a wave travelling in the direction opposite to their motion, pushing water backwards and gaining thrust as a consequence of momentum conservation. The motion of the fin has been studied and reproduced with a series of articulated mechanisms. In this work the optimization of the mechanism’s geometry is described and the experimental results on the reconstructed fin are presented

CONTINUUM ISOTROPY LOCI OF A 2-DOF PARALLEL KINEMATIC MANIPULATOR

ABSTRACT Parallel Kinematic Machines (PKM

THE GENERALIZED JACOBIAN MATRIX AND THE MANIPULATORS KINETOSTATIC PROPERTIES

Manipulator kinetostatic performances are usually investigated considering only the geometrical structure of the robot, neglecting the effect of the drive system. In some circumstances this approach may leads to errors and mistakes. This may happen if the actuators are not identical to each other or when the employed transmission ratio are not identical and/or not constant. The paper introduces the so called “Generalized Jacobian Matrix” obtained identifying an appropriate matrix, generally diagonal, defined in order to: 1. properly weigh the different contributions of speed and force of each actuator. 2. describe the possible non-homogeneous behaviour of the drive system that depends on the configuration achieved by the robot. Theoretical analysis is supported by examples highlighting some of the most common mistakes done in the evaluation of a manipulator kinetostatic properties and how they can be avoided using the generalized jacobian matrix.</jats:p