Biomedical subjects

A R Rocha

Publications and source records attributed to A R Rocha.

3 recordsLinked to original sources

PubMed2005

Conductance oscillations in zigzag platinum chains.

Using first principles simulations we perform a detailed study of the structural, electronic, and transport properties of monatomic platinum chains, sandwiched between platinum electrodes. First, we demonstrate that the most stable atomic configuration corresponds to a zigzag arrangement that gradually straightens as the chains are stretched. Second, we find that the averaged conductance shows slight parity oscillations with the number of atoms in the chain. Additionally, the conductance of chains of fixed oscillates as the end atoms are pulled apart, due to the gradual closing and opening of conductance channels as the chain straightens.

Journal Article↗

PubMed2004

Indication of unusual pentagonal structures in atomic-size Cu nanowires.

We present a study of the structural and quantum conductance properties of atomic-size copper nanowires generated by mechanical stretching. The atomistic evolution was derived from time-resolved electron microscopy observations and molecular dynamics simulations. We have analyzed the quantum transport behavior by means of conductance measurements and theoretical calculations. The results suggest the formation of an unusual and highly stable pentagonal Cu nanowire with a diameter of approximately 0.45 nm and approximately 4.5 conductance quanta.

Journal Article↗

PubMed1997

An expert system for diagnosis of acute myocardial infarction with ECG analysis.

Coronary heart disease is one of the most prevalent and costly health care problems in the world. The early and accurate diagnosis of coronary heart disease is a major problem in emergency settings. However, many primary and secondary hospitals and primary emergency units lack cardiologists on call which makes the diagnosis difficult. This paper describes an expert system for diagnosis of acute myocardial infarction developed to aid physicians without cardiology specialization. Our main goal was to develop an expert system that assists in the diagnosis and indicates the need of hospitalization in a coronary unit.

Electrocardiography↗