Concomitant gastric adenocarcinoma and stromal tumor in a woman with polymyalgia rheumatica

Gastrointestinal stromal tumors （GISTs） are rare neoplasms （1%） of the gastrointestinal tract and to our knowledge only rare cases of synchronous presentation of gastric carcinomas and GISTs are reported in the literature. A 72-year-old female with a simultaneous presentation of gastric adenocarcinoma and GIST is presented. Moreover, due to polymyalgia rheumatica the patient received corticosteroids as treatment for the last 3 years. The concomitant occurrence of these neoplasms may involve common carcinogenic factors and there could be an association with polymyalgia rheumatica either as a paraneoplastic presentation or due to its treatment with corticosteroids.

Flatness-Based Control in Successive Loops for Unmanned Aerial Vehicles and Micro-Satellites

The control problem for the multivariable and nonlinear dynamics of unmanned aerial vehicles and micro-satellites is solved with the use of a flatness-based control approach which is implemented in successive loops.The state-space model of(i)unmanned aerial vehicles and(ii)micro-satellites is separated into two subsystems,which are connected between them in cascading loops.Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input–output linearized flat systems.The state variables of the second subsystem become virtual control inputs for the first subsystem.In turn,exogenous control inputs are applied to the first subsystem.The whole control method is implemented in two successive loops and its global stability properties are also proven through Lyapunov stability analysis.The validity of the control method is confirmed in two case studies:(a)control and trajectories tracking for the autonomous octocopter,(ii)control of the attitude dynamics of micro-satellites.

Non-linear optimal control for multi-DOF electro-hydraulic robotic manipulators

A non-linear optimal(H-infinity)control approach is proposed for the dynamic model of multi-degree-of-freedom(DOF)electro-hydraulic robotic manipulators.Control of electro-hydraulic manipulators is a non-trivial problem because of their non-linear and multi-variable dynamics.In this study,the considered robotic system consists of a multi-link robotic manipulator that receives actuation from rotary electro-hydraulic drives.The article's approach relies first on approximate linearisation of the state-space model of the electro-hydraulic manipulator,according to first-order Taylor series expansion and the computation of the related Jacobian matrices.For the approximately linearised model of the manipulator,a stabilising H-infinity feedback controller is designed.To compute the controller's gains,an algebraic Riccati equation is solved at each time-step of the control algorithm.The global stability properties of the control scheme are proven through Lyapunov analysis.The proposed control method retains the advantages of typical optimal control,i.e.fast and accurate tracking of the reference setpoints under moderate variations of the control inputs.