Data acquisition system for MAET with magnetic field measurements.

Magneto-acousto-electrical tomography (MAET) is an imaging modality to image the electrical conductivity of biological tissues. It is based on electrical current induction by using ultrasound under a static magnetic field. The aim of this study is to develop a data acquisition system for MAET based on magnetic field measurements. The static magnetic field is generated by six permanent neodymium magnets. A 16-element linear phased array (LPA) transducer is utilized to generate acoustic pressure waves inside the phantom. To measure the magnetic field intensity generated by the induced currents, contactless receiver sensors are developed using two similar disk multiple layer coils, which are Helmholtz coil sensor. Physical properties and electrical characteristics of the sensors are assessed. A two-stage cascaded amplifier is designed and utilized in the receiving system. The gain of the cascaded amplifier at 1 MHz is adjusted to be 96 dB. Experimental studies are conducted with two different phantoms, having 3 S m-1 and 58 S m-1 electrical conductivity, respectively. A-scan and B-scan images of phantoms are obtained with the LPA transducer. Comparison of the ultrasound (A-scan) and MAET signals reveals that 3 S m-1 conductive inhomogeneity can be detected with this data acquisition system. Furthermore, the front and rear interfaces of an inhomogeneity ([Formula: see text]) of 58 S m-1 conductivity are detectable.

War and infection in the pre-antibiotic era: the Third Ottoman Army in 1915.

BACKGROUND: The aim of this study, which evaluated historical data, was to delineate the probable impacts of infectious diseases on human populations under extraordinary circumstances. The second goal was to disclose the mortality rates for infectious diseases in the absence of antibiotics. METHODS: The Third Ottoman Army records at the Turkish General Staff Military History and Strategic Study Directorate were studied retrospectively for the period between March 1915 and February 1916. RESULTS: For the Third Ottoman Army, the number of infection-related deaths over the single-year period was 23,601. Malaria, relapsing fever and dysentery were the most common infections. In that pre-antibiotic era, the highest mortality rates were seen for cholera (80%), pulmonary tuberculosis (58%) and typhoid fever (51%). However, typhus had the maximum share in soldier deaths (6053 soldiers). The rate of vector-borne infections peaked in the summer of 1915, while the frequency of respiratory tract infections was highest in the colder months. In contrast, gastrointestinal tract infections appeared to maintain a steady state throughout the year. CONCLUSIONS: If the wartime data for 1915 are accepted to provide a model for extraordinary circumstances in the 21st century, vector-borne, respiratory tract and gastrointestinal infections can be accepted as the challenging issues with significant mortality.