Rabbit Anti-Human AEN Polyclonal antibody

Black esophagus, also known as acute esophageal necrosis (AEN) syndrome, is a rare entity characterized by patchy or diffuse circumferential black pigmentation of the esophageal mucosa from ischemic necrosis. It may present with life-threatening upper gastrointestinal hemorrhage resulting in high mortality in immunocompromised patients. Advanced age with multiple comorbidities compounded with compromised hemodynamic states are poor prognostic factors. Findings on laboratory work-up and radiological imaging are non-specific. After initial resuscitation, endoscopic evaluation and histological examination of esophageal biopsy are diagnostic. Early recognition and aggressive resuscitation are the fundamental principles for the management of AEN and better outcome of the disease. We report a case of a 56-year-old woman with diabetes mellitus, gastro-esophageal reflux disease, and active alcohol binging who presented with hematemesis and acute epigastric pain due to AEN. This case illustrates a rare etiology of AEN due to active alcohol drinking, which may be overlooked. Physician awareness about this etiology is important as early recognition and timely management may improve survival.

Communication across an additive exponential noise (AEN) channel is studied. The AEN channel is derived from a continuous-time Gaussian channel by assuming decoherence between the signal and noise components. Decoherence renders impossible the use of the complex amplitude and information is transmitted by modulating the signal energy. The AEN channel is shown to perform closely-in terms of channel, information rate, and error probability of binary codes, including the use of bit-interleaved coded modulation-to an equivalent discrete-time Gaussian channel of identical signal-to-noise ratio. Constellations are designed for low signal-to-noise ratios, where the minimum energy per bit is not universally attained by all modulations, and for high signal-to-noise ratios, where an equiprobable nonuniform constellation 0.76 dB away from capacity is described. The multiple-access AEN channel is also considered: its capacity region coincides with that of the Gaussian equivalent; feedback does not, however, enlarge the capacity region.