LuxS is responsible for the production of autoinducer 2 (AI-2), which functions in Vibrio harveyi as a quorum-sensing signal that controls the cell density-dependent expression of the lux operon. In nonluminescent organisms, the physiologic role of AI-2 is not clear. We report that inactivation of luxS in Actinobacillus actinomycetemcomitans JP2 results in reduced growth of the mutant, but not ...

BACKGROUND The occurrence of Parkinson's disease (PD) is known to be associated both with increased nigrostriatal iron content and with low serum cholesterol and PD, but there has been no study to determine a potential relationship between these two factors. METHODS High-resolution MRI (T1-, T2, and multiple echo T2*-weighted imaging) and fasting lipid levels were obtained from 40 patients wi...

Introduction: Cellular imaging of the immune response by MRI has been used to reveal the existence of particular cells in the tissue, which has several important applications in biomedical research. One important application is the detection of the rejection severity in cardiac allograft transplantation. Non-invasive methods using ultra-small superparamagnetic iron oxide (USPIO) and micrometer-...

Previous studies have accurately determined the effect of transition metal point defects on properties bcc iron. The magnetic monolayers iron surfaces been studied equally intensively. In this work, we investigated 3d, 4d, and 5d transition-metal (TM) atomic in Fe/TM/Fe sandwiches using full-potential local-orbital (FPLO) scheme density functional theory. We prepared models structures supercell...

Introduction Iron is the most abundant element in the Earth’s core. However, the density of the outer core is about 10% lower than the density of iron at the pressure and temperature conditions of the outer core, indicating the presence of a low-atomic-weight component (such as H, C, O, Si, or S) in the core [1]. There is also evidence that the inner core may be less dense than pure iron and th...

Iron chalcogenide superconductors have become one of the most investigated superconducting materials in recent years due to high upper critical fields, competing interactions and complex electronic and magnetic phase diagrams. The structural complexity, defects and atomic site occupancies significantly affect the normal and superconducting states in these compounds. In this work we review the v...

The Earth’s solid inner core consists mainly of iron (Fe), alloyed with lighter elements, such as silicon (Si). Interpretation of seismic anisotropy and layering requires knowledge of the stable crystal structure in the inner core. We report ab initio density functional theory calculations on the free energy and vibrational stability of pure iron and Fe–Si alloys at conditions representative of...

background and objectives: bacteria need iron for growth and most of them can actively acquire fe ions using especial iron-chelating proteins which named siderophores. we aimed to determine the frequencies of iuca, iron and irp2 genes in the uropathogenic escherichia coli (upec) isolates. we also analyzed the effects of siderophore genes beside iron supplements on growth rate of the isolates. m...

The nature of the spin-density wave (SDW) and its relation with superconductivity are crucial issues in the newly discovered iron-pnictide superconductors. Particularly, it is unclear whether the superconducting phase and SDW are truly exclusive from each other. We here report splittings of the band structures in Sr1-xKxFe2As2 (x=0, 0.1, 0.18), and their unusual doping dependence. Our data on s...