Introduction: Positive contrast by means of selective excitation is a helpful way of visualizing objects of clinical interest, like iron-labeled cells, paramagnetic agents or labeled therapeutics. In regular gradient echo imaging, these entities cause negative contrast due to intra voxel dephasing effects which cannot be distinguished from signal voids caused by other effects, and is subjected ...

One-electron reduction of the synthetic tetramers [FemSa(SR)~] 2(R CHgPh, Ph), by chemical and electrochemical methods affords the corres~ofiding-trianions. ~The collective results from optical, electron paramagnetic resonance, and M~ssbauer spectroscopy, when compared to available data for reduced 4-Fe and 8-Fe ferredoxi~ proteins and super-reduced Chromatium high-potential protein, reveal tha...

iron is an essential microelement for plant growth. low content of organic matter and excess application of phosphate fertilizer in soils can be affected on availability of iron. in this study the effect of iron, phosphorus and organic matter on growth and iron uptake of mays was evaluated. a greenhouse experiment was conducted with two levels of cattle manure (0 and 1 %), three levels of phosp...

Magnetoreception and iron biomineralization in honeybees (Apis mellifera) have been investigated for several decades. Numerous open questions are still been hotly debated, especially the location of superparamagnetic magnetite. To solve this argument, we use the size-density purification technique to purify the iron granules of trophocytes and determined their magnetic properties, which include...

A facile homogenous precipitation method has been developed for the synthesis of multifunctional, magnetic, luminescent nanocomposites with Fe(3)O(4) nanoparticles as the core and europium-doped yttrium oxide (Y(2)O(3):Eu) as the shell. The nanocomposites showed both super-paramagnetic behavior and unique europium fluorescence properties with high emission intensity. Their surface has been modi...

1. It is confirmed that there are two e.p.r. (electron-paramagnetic-resonance) signals associated with fully loaded ovotransferrin, which has two iron-binding sites. 2. Through experiments in which either of the two sites of whole ovotransferrin is occupied, the other being empty, the first occupied site is shown to belong to the N-terminal region of the protein; the second occupied site is in ...

The magnetic properties of the Fe1−xAgxCr2S4 (0 < x 0.2) solid solution were investigated in temperature range 4–300 K a DC field 0.1 and 45 kOe. is characterized by transition from paramagnetic to ferromagnetic state (Tc) irreversibility (Tirr). replacement iron with silver ions leads an increase Curie temperatures 185 (x = 0) 216 Tcusp 125 0.2). A section phase diagram region under study h...

Metalloproteins often contain metal centers that are paramagnetic in some functional state of the protein; hence electron paramagnetic resonance (EPR) spectroscopy can be a powerful tool for studying protein structure and function. Dipolar spectroscopy allows the determination of the dipole-dipole interactions between metal centers in protein complexes, revealing the structural arrangement of d...