in this paper we prove that each element of any regular baer ring is a sum of two units if no factor ring of r is isomorphic to z_2 and we characterize regular baer rings with unit sum numbers $omega$ and $infty$. then as an application, we discuss the unit sum number of some classes of group rings.

To control such a hemorrhage, a displaced pelvic ring must be rapidly reduced and stabilized with a pelvic binder, an external fixator, or a pelvic clamp. Among them, pelvic clamps can be life-saving but pin malposition may cause vascular complications. We present a case of superior gluteal artery pseudoaneurysm caused by AO pelvic C-clamp pin malposition.

We present an unusual case of vascular sling, tracheal stenosis by complete cartilaginous ring, and aberrant left subclavian artery with right aortic arch that underwent successful surgical repair for the sling. These abnormalities were suspected from unusual multiple indentations found on esophagogram. Complete preoperative diagnosis was established with chest computerized tomogram combined wi...

A case of Wolff-Parkinson-White syndrome type A with coexisting ipsilateral bundle branch block is presented. The diagnosis was suspected because of subtle electrocardiographic changes and was confirmed at electrophysiological study. Necropsy showed a vascular anomaly of the coronary sinus that contained bundles of myocardial muscle which crossed the atrioventricular ring at a site that was con...

Double aortic arch is a common form of complete vascular ring that encircles both the trachea and the esophagus, and presents with various respiratory and esophageal symptoms, usually in the pediatric population. We present a case of double aortic arch in an adult patient that manifested as massive upper gastrointestinal bleeding after prolonged nasogastric intubation.