Liaison based assembly design

Liaison Based Assembly Design extends the current information infrastructure to support design in terms of kinematic relationships between parts, or liaisons. These liaisons capture information regarding contact, degrees-of-freedom constraints and containment relationships between parts in an assembly. The project involved defining a useful collection of liaison representations, investigating their properties, and providing for maximum use of the data in downstream applications. We tested our ideas by implementing a prototype system involving extensions to Pro/Engineer and the Archimedes assembly planner. With an expanded product model, the design system is more able to capture design intent. When a product update is attempted, increased knowledge availability improves our ability to understand the effect of design changes. Manufacturing and analysis disciplines benefit from having liaison information available, so less time is wasted arguing over incomplete design specifications and our enterprise can be more completely integrated

Measuring worst-case errors in a robot workcell

Errors in model parameters, sensing, and control are inevitably present in real robot systems. These errors must be considered in order to automatically plan robust solutions to many manipulation tasks. Lozano-Perez, Mason, and Taylor proposed a formal method for synthesizing robust actions in the presence of uncertainty; this method has been extended by several subsequent researchers. All of these results presume the existence of worst-case error bounds that describe the maximum possible deviation between the robot`s model of the world and reality. This paper examines the problem of measuring these error bounds for a real robot workcell. These measurements are difficult, because of the desire to completely contain all possible deviations while avoiding bounds that are overly conservative. The authors present a detailed description of a series of experiments that characterize and quantify the possible errors in visual sensing and motion control for a robot workcell equipped with standard industrial robot hardware. In addition to providing a means for measuring these specific errors, these experiments shed light on the general problem of measuring worst-case errors

An unusual vascular ring: Origin of a ductus arteriosus from an aberrant right subclavian artery in a neonate with tetralogy of Fallot

A 2.6kg male infant with a prenatal diagnosis of congenital heart disease was delivered via normal vaginal delivery to a 29-year-old mother and subsequently evaluated at our institute. The patient was found to have arterial pre- and post-ductal saturations of 80% and physical examination revealed a holosystolic murmur. The patient did not have stridor. Low ionized calcium was also noted. Echocardiography demonstrated tetralogy of Fallot with an imperforate pulmonary valve and an unusual ductal flow pattern. Prostaglandin E1 infusion was commenced.peer-reviewe

A newborn with cardiomegaly

An infant with Down’s syndrome was noted to have hypoxemia and tachypnea at birth. The clinical examination, electrocardiogram (ECG) and the chest X-ray findings suggested a specific diagnosis that is not usually associated with Down’s syndrome. Despite the extremely rare association of Ebstein’s anomaly with Down’s syndrome, this diagnosis was highly suspected from the initial evaluation. An echocardiogram confirmed the diagnosis of Ebstein’s anomaly in this neonate. So far, only about seven cases of Ebstein’s anomaly associated with Down’s syndrome have been reported in the literature. This case is discussed for its rarity; it also highlights the importance of clinical examination and initial investigations that had suggested the diagnosis well prior to that of the echocardiogram

Does Prophylactic Ibuprofen After Surgical Atrial Septal Defect Repair Decrease the Rate of Post-Pericardiotomy Syndrome?

© 2018 Springer Science+Business Media, LLC, part of Springer Nature Post-pericardiotomy syndrome (PPS) is an inflammatory process involving the pleura, pericardium, or both and occurs after cardiothoracic surgery. Surgical atrial septal defect (ASD) closure is associated with higher incidence of PPS post-operatively as compared to other operations. Reported incidence of PPS varies from 1 to 40%. NSAIDs are often used to treat PPS and in our center, some practitioners have prescribed ibuprofen prophylactically. This study sought to investigate the impact of prophylactic treatment with ibuprofen on the development and severity of PPS following surgical ASD closure, with particular attention to secundum-type ASDs. We retrospectively reviewed clinical and operative data of all surgical ASD repairs in our center from 1/2007 to 7/2017. ASDs were grouped by subtype. PPS was considered positive if the primary cardiologist diagnosed and documented clinical signs of PPS on post-operative outpatient follow-up. Records were reviewed to confirm documented diagnosis of PPS. A total of 245 cases were reviewed with 207 having sufficient data. Median age was 2 years (range 4 months–27 years), female 57%. Overall incidence of PPS was 10%. There was no difference in incidence of PPS in those prescribed ibuprofen as compared to those who were not. This was true for both the entire cohort and the subgroup analysis (P = 1.0). Four patients overall required pericardiocentesis, none of whom received prophylactic ibuprofen. Prophylactic ibuprofen prescription following surgical ASD repair did not reduce the rate of PPS in our cohort

A unique approach to Fontan revision in a cyanotic patient

© 2020 Elsevier B.V. Unilateral pulmonary arteriovenous malformations can develop in heterotaxy patients with single ventricle physiology after Kawashima procedure due to preferential flow streaming to one lung. We present the case of a 25 year old patient with this physiology who presented with resting cyanosis to 75% in room air. Our patient underwent a unique revision to reverse the development of arteriovenous malformations with partial resection of her hepatic vein-right pulmonary artery conduit and placement of new conduit connecting hepatic veins to innominate vein which then drained into left-sided superior vena cava, resulting in favorable outcome