Induced current magnetic resonance-electrical impedance tomography

Magnetic resonance-electrical impedance tomography (MR-EIT) is a conductivity imaging method based on injecting currents into the object. In this study, a new MR-EIT method, whereby currents are induced inside the object by using external coils, is proposed. This new method is called induced current magnetic resonance-electrical impedance tomography. In induced current MR-EIT surface electrodes are not used and thereby artifacts due to electrodes are eliminated. The reconstruction algorithm is based on the measurement of only one component of the secondary magnetic flux density. The algorithm is an iterative one, is 3D and is based on the solution of a linear matrix equation at each iteration. For the measurement of secondary magnetic flux density, a pulse sequence to be used in the MRI system is proposed. Numerical simulations are performed to test the algorithm for both noise-free and noisy cases. The singular value behavior of the matrix is monitored and it is observed that at least two current induction profiles improve the images significantly. It is shown that induced current MR-EIT can be used to reconstruct absolute conductivity images without the need for any additional peripheral voltage measurement. © 2005 IOP Publishing Ltd

Metal pollution in biotic and abiotic samples of the Buyuk Menderes River, Turkey

WOS: 000397007200006PubMed ID: 26971518The Buyuk Menderes River (BMR) is one of the largest rivers in Turkey. This river irrigates efficient farmlands and includes tributaries of other rivers and streams and many populated towns within its limits in the Egc region. Both the estuary and Isikli Lake serve as a sanctuary for various waterbirds. Therefore, the BMR plays a critical role both for the inhabitants and for the ecosystem organisms in its environs. In the present study, we analyzed levels of metals including iron, barium, zinc, vanadium, cobalt, chromium, cadmium, copper, nickel, aluminum, arsenic, manganese, antimony, silver, selenium, boron, mercury, titanium, and lead in river water, sediment, fish (Cyprinus carpio; common carp), and in various waterbird (Fulica atra, Euroasian coot; Larus michahellis, yellow-legged gull; Ardea cinerea, grey heron; Larus melanocephalus, Mediterranean gull; and Pelecanus crispus, pelican) samples. Analyses were performed using an inductively coupled plasma-mass spectrometry (ICP-MS) instrument after sample preparation. Comparing metal concentrations among different sample types, it was found that barium, aluminum, and zinc are the major metals in river water, and zinc in common carp muscle, while iron, aluminum, and manganese are the major metals in sediments. Iron, zinc, copper, and aluminum were the highest in waterbird muscle tissue. Iron and barium were found to be the major metals in eggshell, while iron and zinc are the major metals in egg samples. A simple Bworst-case scenario" model of risk assessment revealed that some of the analyzed metals may pose a risk for human health through consuming fish.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Scientific and Technical Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112Y199]This study was supported by a grant from TUBITAK, Scientific and Technical Research Council of Turkey (112Y199)