A system for calculating the greatest common denominator implemented using asynchrobatic logic

An asynchrobatic system that uses Euclid's algorithm to calculate the greatest common denominator of two numbers is presented. This algorithm is a simple system that contains both repetition and decision, and therefore demonstrates that asynchrobatic logic can be used to implement arbitrarily complex computational systems. Under typical conditions on a 0.35 mum process, a 16-bit implementation can perform a 24-cycle test vector in 2.067 mus with a power consumption of 3.257 nW

Using positive feedback adiabatic logic to implement reversible Toffoli gates

A reversible, positive feedback adiabatic logic circuit is presented, which by implementing the universal Toffoli gate demonstrates that reversible logic circuits can be created and implemented using this adiabatic logic family. When compared to circuits with similar circuit structures that do not incorporate complete recovery logic, the use of reversible structures shows a reduction in energy losses by a mean of just under 63%

An asynchrobatic, radix-four, carry look-ahead adder

A low-power, Asynchrobatic (asynchronous, quasi-adiabatic), sixteen-bit, radix-four, parallel-prefix adder circuit is presented. The results show that it is an efficient, low power design, and that as would be expected with an asynchronous design, its performance is determined by its operating conditions. On a 0.35 mum CMOS process, under ldquotypicalrdquo process conditions, operating at an effective frequency of 22 MHz, an addition can be performed using 69 pW, with 48.3 pW used by the control logic and 20.7 pW by the data-path

Asynchrobatic logic for low-power VLSI design

In this work, Asynchrobatic Logic is presented. It is a novel low-power design style that combines the energy saving benefits of asynchronous logic and adiabatic logic to produce systems whose power dissipation is reduced in several different ways. The term “Asynchrobatic” is a new word that can be used to describe these types of systems, and is derived from the concatenation and shortening of Asynchronous, Adiabatic Logic. This thesis introduces the concept and theory behind Asynchrobatic Logic. It first provides an introductory background to both underlying parent technologies (asynchronous logic and adiabatic logic). The background material continues with an explanation of a number of possible methods for designing complex data-path cells used in the adiabatic data-path. Asynchrobatic Logic is then introduced as a comparison between asynchronous and Asynchrobatic buffer chains, showing that for wide systems, it operates more efficiently. Two more-complex sub-systems are presented, firstly a layout implementation of the substitution boxes from the Twofish encryption algorithm, and secondly a front-end only (without parasitic capacitances, resistances) simulation that demonstrates a functional system capable of calculating the Greatest Common Denominator (GCD) of a pair of 16-bit unsigned integers, which under typical conditions on a 0.35μm process, executed a test vector requiring twenty-four iterations in 2.067μs with a power consumption of 3.257nW. These examples show that the concept of Asynchrobatic Logic has the potential to be used in real-world applications, and is not just theory without application. At the time of its first publication in 2004, Asynchrobatic Logic was both unique and ground-breaking, as this was the first time that consideration had been given to operating large-scale adiabatic logic in an asynchronous fashion, and the first time that Asynchronous Stepwise Charging (ASWC) had been used to drive an adiabatic data-path

Diagnosis and management of Barrett’s esophagus for the endoscopist

In Barrett’s esophagus, the stratified squamous epithelium lining the esophagus is replaced by specialized intestinal-type columnar epithelium. The prevalence of Barrett’s esophagus has ranged from 0.9% to 4.5%. The rate of progression from Barrett’s esophagus to esophageal adenocarcinoma is 0.5% per patient-year. Proton-pump inhibitors are the mainstay of symptom control in Barrett’s patients. Nondysplastic Barrett’s and Barrett’s with low-grade dysplasia (LGD) are typically managed by periodic surveillance. Radiofrequency ablation is being evaluated as a modality for managing nondysplastic Barrett’s and Barrett’s with LGD. The options for the management of Barrett’s patients with high-grade dysplasia (HGD) include endoscopic therapy, surgery, and intensive surveillance until biopsy reveals adenocarcinoma. Endoscopic therapy involves endoscopic mucosal resection (EMR) and ablation. More aggressive techniques such as endoscopic submucosal dissection and larger segment endoscopic mucosal resection are under study. In this review, we discuss the diagnosis and management of Barrett’s esophagus. The recommendations from the major gastroenterologic societies and the current and investigational endoscopic modalities for the management of Barrett’s esophagus with and without dysplasia are reviewed