Diagnosis and Endoscopic Treatment of Hemobilia Due to Biliary Angiodysplasia: A Case Report and Literature Review.

Hemobilia is described as bleeding from the intra- or extrahepatic biliary tree expressed through the major duodenal papilla into the duodenum, with angiodysplasia of the major biliary duct as a rare etiological factor with few cases reported in the literature. Cholangioscopy plays a pivotal role in diagnosing and making therapeutic decisions regarding biliary tract lesions. We report a case of the diagnosis and treatment of hemobilia secondary to bleeding from angiodysplasia of the major biliary duct, which was resolved after the placement of a fully covered metallic stent, with a review of the literature.

Linear quadratic regulator design via metaheuristics applied to the damping of low-frequency oscillations in power systems.

This paper proposes the application of control by state feedback using the linear quadratic regulator (LQR) optimized by metaheuristics to damp low-frequency electromechanical oscillations in electrical power systems. The current sensitivity model was used to represent the single machine infinite bus (SMIB) system in the time domain. The weighting matrices of the LQR were adjusted using four different algorithms: (i) the genetic algorithm, (ii) the differential evolution algorithm, (iii) the particle swarm optimization algorithm, and (iv) the gray wolf optimization (GWO) algorithm.