fMRI of the auditory system: understanding the neural basis of auditory gestalt

Functional magnetic resonance imaging (fMRI) has rapidly become the most widely used imaging method for studying brain functions in humans. This is a result of its extreme flexibility of use and of the astonishingly detailed spatial and temporal information it provides. Nevertheless, until very recently, the study of the auditory system has progressed at a considerably slower pace compared to other functional systems. Several factors have limited fMRI research in the auditory field, including some intrinsic features of auditory functional anatomy and some peculiar interactions between fMRI technique and audition. A well known difficulty arises from the high intensity acoustic noise produced by gradient switching in echo-planar imaging (EPI), as well as in other fMRI sequences more similar to conventional MR sequences. The acoustic noise interacts in an unpredictable way with the experimental stimuli both from a perceptual point of view and in the evoked hemodynamics. To overcome this problem, different approaches have been proposed recently that generally require careful tailoring of the experimental design and the fMRI methodology to the specific requirements posed by the auditory research. The novel methodological approaches can make the fMRI exploration of auditory processing much easier and more reliable, and thus may permit filling the gap with other fields of neuroscience research. As a result, some fundamental neural underpinnings of audition are being clarified, and the way sound stimuli are integrated in the auditory gestalt are beginning to be understood.     

Carbon dioxide activation by surface excess electrons: an EPR study of the CO2- radical ion adsorbed on the surface of MgO

The CO2- radical anion has been generated at the surface of MgO by direct electron transfer from surface trapped excess electrons and characterized by electron paramagnetic resonance spectroscopy. Both 13C and 17O hyperfine structures have been resolved for the first time, leading to a detailed mapping of the unpaired electron spin density distribution over the entire radical anion. The magnetic equivalence of the two O nuclei has been ascertained allowing a side-on adsorption structure at low-coordinate Mg2+ ions to be proposed for the surface stabilized radical.     

Crystallization‐Induced Asymmetric Transformations. Enantiomerically pure (−)‐(R)‐ and (+)‐(S)‐2,3‐Dibromopropan‐1‐ol and Epibromohydrins. A Study of Dynamic Resolution via the Formation of Diastereoisomeric Esters

(S)‐2,3‐Dibromopropan‐1‐ol of high enantiomer excess was obtained by crystallization‐induced asymmetric transformations of racemic 2,3‐dibromopropan‐1‐ol esterified with N‐([1,1′‐biphenyl]‐4‐ylcarbonyl‐L ‐alanine; in particular, an asymmetric transformation of the first type (involving bromide exchange to equilibrate the diastereoisomeric esters) and an asymmetric transformation of the second type (involving a transesterification of diastereoisomeric esters with excess racemic alcohol) were devised.     

A nonlinear homogenization procedure for periodic masonry

The present paper deals with the problem of the determination of the in-plane behavior of masonry material. The masonry is considered as a composite material composed by a regular distribution of blocks connected by horizontal and vertical mortar joints. The overall constitutive relationships of the regular masonry are derived by a rational micromechanical and homogenization procedure. Linear elastic constitutive relationship is considered for the blocks, while a new special nonlinear constitutive law is proposed for the mortar joints. In particular, a mortar constitutive law, which accounts for the coupling of the damage and friction phenomena occurring during the loading history, is proposed; the developed model is based on an original micromechanical analysis of the damage process of the mortar joint. Then, an effective nonlinear homogenization procedure, representing the main novelty of the paper, is proposed; it is based on the transformation field analysis, using the technique of the superposition of the effects and the finite element method. The presented methodology is implemented in a numerical code. Finally, numerical applications are performed in order to assess the performances of the proposed procedure in reproducing the mechanical behavior of masonry material.     

Efficient Gene Transfection through Inhibition of β-Sheet (Amyloid Fiber) Formation of a Short Amphiphilic Peptide by Gold Nanoparticles

The effect of citrate-stabilized gold nanoparticles (AuNPs) on the secondary structure of an artificial β-sheet-forming cationic peptide has been studied. The AuNPs inhibited β-sheet formation and led to fragmented fibrils and spherical oligomers with assembled AuNPs on their surface. Besides this structural change, the functional properties of the peptide are also different. Whereas the peptide was unable to act as a vector for gene delivery, formation of a complex with AuNPs allowed successful gene delivery into cells.     

Hydration structure of the Ti(III) cation as revealed by pulse EPR and DFT studies: new insights into a textbook case

The (17)O and (1)H hyperfine interactions of water ligands in the Ti(III) aquo complex in a frozen solution were determined using Hyperfine Sublevel Correlation (HYSCORE) and Pulse Electron Nuclear Double Resonance (ENDOR) spectroscopies at 9.5 GHz. The isotropic hyperfine interaction (hfi) constant of the water ligand (17)O was found to be about 7.5 MHz. (1)H Single Matched Resonance Transfer (SMART) HYSCORE spectra allowed resolution of the hfi interactions of the two inequivalent water ligand protons and the relative orientations of their hfi tensors. The magnetic and geometrical parameters extracted from the experiments were compared with the results of DFT computations for different geometrical arrangements of the water ligands around the cation. The theoretical observable properties (g tensor (1)H and (17)O hfi tensors and their orientations) of the [Ti(H(2)O)(6)](3+) complex are in quantitative agreement with the experiments for two slightly different geometrical arrangements associated with D(3d) and C(i) symmetries.     

Uncertainty of measurement and conformity assessment: a review

The uncertainty of measurement is the key indicator of the quality of any experimental result. Proper consideration of this uncertainty is imperative when testing a sample against legal/compositional limits. This task can be quite challenging when the entity measured in the investigated sample is so close to the limit that its uncertainty, however estimated, critically affects decision-making. This explains the many literature contributions discussing the problem. Even though some of the most authoritative organisations have issued specific guidelines aimed at assisting the staff involved in such measurements, several aspects of conformity testing are still debated in the literature. In this review, after a short outline of existing information, somewhat more detailed insight is given into the guidelines of ASME, ISO, and Eurachem/CITAC, because they are the most useful tools for operators of testing and calibration laboratories. Some aspects of Council Directive 96/23/EC are also discussed. Insight into the contents of the mentioned documents enables emphasis of analogies and discrepancies.