Aerodynamic and acoustical effects caused by placing two prefabricated duct silencers in series

It once was not uncommon to find ductborne noise control designs and recommendations that would attempt to provide high sound attenuation values, especially for problematic lower frequencies, by using a pair of prefabricated duct silencers in series with one another, sometimes immediately adjacent but typically separated by some distance. Similarly, heating, ventilating, and air-conditioning (HVAC) duct silencers are occasionally required to accommodate fire dampers or access sections that effectively break up the silencer along its length, creating an empty gap between the noise-attenuating internal elements. Typical published performance characteristics of prefabricated duct silencers do not include effects from the use of additional silencers nearby and little information is available in common duct design and application literature. This paper will present information from a series of tests of various silencers in different configurations and spacings in an aero-acoustic test facility that will help describe the effects on insertion loss, generated noise, and pressure drop.

Cholelithiasis, choledocholithiasis and hepatolithiasis with secondary necrotizing hepatitis and cholangiohepatitis in a dairy cow

Biliary calculi are rare in cattle and occur usually in the gallbladder, without clinical signs. In humans, cholelithiasis is a common cause of hepatic abscess due calculi microbiota. Here is described a case of cholelithiasis, choledocholithiasis and hepatolithiasis in a 10-year-old female mixed breed dairy cow. The animal died during physical examination with signs as cachexia, icterus, and fever. At necropsy, a large number of green calculi were observed in the gallbladder, common duct lumen and in markedly distended biliary ducts. The liver was firm and decreased in volume with multiple abscess and multiple red foci measuring 0.5 cm in diameter in the hepatic parenchyma. Microscopically in the liver, marked ductal proliferation and abscedative cholangiohepatitis with abundant fibrosis and multiple foci of hepatocytes necrosis. In conclusion, choledocholithiasis and hepatolithiasis may occur in cattle and cause significant clinical signs and pathological alterations.

Shape and Enhancement Analysis as a Useful Tool for the Presentation of Blood Hemodynamic Properties in the Area of Aortic Dissection

The aim of this study was to create a mathematical approach for blood hemodynamic description with the use of brightness analysis. Medical data was collected from three male patients aged from 45 to 65 years with acute type IIIb aortic dissection that started proximal to the left subclavian artery and involved the renal arteries. For the recognition of wall dissection areas Digital Imaging and Communications in Medicine (DICOM) data were applied. The distance from descending aorta to the diaphragm was analyzed. Each time Feret (DF) and Hydraulic (DHy) diameter were calculated. Moreover, an average brightness (BAV) was analyzed. Finally, to describe blood hemodynamic in the area of aortic wall dissection, mathematical function combining difference in brightness value and diameter for each computed tomography (CT) scan was calculated. The results indicated that DF described common duct more accurately compare to DHy. While, DHy described more accurately true and false ducts. Each time when connection of true and false duct appeared, true duct had lower brightness compare to common duct and false duct. Moreover, false duct characterized with higher brightness compare to common duct. In summary, the proposed algorithm mimics changes in brightness value for patients with acute type IIIb aortic dissection.

DOZ047.99: A unique case of ‘esophageal trachea’ requiring a multistep sequential surgical reconstruction

Introduction Communicating bronchopulmonary foregut malformations (CBPFMs) have been defined by Srikanth et al. in 1992 as a fistula between a portion of respiratory tissue and esophagus/stomach. Four types of CBPFMs have been described, none of those contemplating a complete communication between the distal trachea and esophagus. Case Report This study reports a case of a full-term neonate presenting with a VACTERL association and a tracheoesophageal malformation characterized by the presence of a long common duct including both the middle esophagus and distal trachea, which consists in esophageal tissue, without any cartilaginous rings 3–4 cm above the carina. A few days after birth, the esophagus and trachea have been surgically separated, keeping the common duct on the tracheal side and creating a residual long-gap esophageal atresia (LGEA). The resulting severe tracheomalacia has been simultaneously treated by posterior splinting using an autologous pericardium patch, as well as by anterior aortopexy. A terminal esophagostomy and a gastrostomy have been created to postpone esophageal reconstruction. Since the age of 18 months, delayed repair of LGEA has been performed by using a multistep strategy consisting of a combination of Kimura extrathoracic esophageal elongations and distal stump Foker external traction. Since no cartilaginous rings were present, refractory tracheomalacia has been further treated by a tracheoplasty through a combined median sternotomy and tracheoscopy approach at the age of 3 years by using a semitubular rigid Gore-Tex® prosthesis for an anterior external stenting. Today, 9 months after last surgery, complete weaning from respiratory support has been stably achieved, as well as full oral feeding. Conclusions This is the first description of an ‘esophageal trachea’, which may be considered as a new anatomic variant of CBPFMs. Multidisciplinary medical and surgical expertise was needed to manage this particular case, in order to properly plan multiple sequential surgical approaches. Native esophageal reconstruction should always be considered, even because colonic or gastric transposition might further affect severe tracheomalacia, resulting in more challenging treatment.