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Abstract: A general protocol for the design of successful chiral derivatizing agents (CDAs) for the NMR assignment of absolute configuration is described. The design of the most efficient arylalkoxyacetic acid reagent for the assignment of chiral thiols is taken as example. The importance of theoretical calculations in the discovery of the conformational preference of modelled arylmethoxyacetic acid (AMAA) thioesters is stressed, as well as NMR experiments to confirm the conformations predicted for the different CDAs and to select for synthesis the most adequate for that substrate. The modification of the aryl moiety of the AMAA system has shown not to provide especially good CDAs while the introduction of a sterically hindered tert-BuO group results in a more appropriate conformation leading to 2-naphtyl-tert-butoxyacetic acid (2-NTBA) as the most efficient CDA for thiols. [Copyright &y& Elsevier]

A general methodology for assigning the configuration of chiral mono- and polyfunctional compounds by NMR is presented. The approach is based on the use of polystyrene-bound chiral derivatizing agents (CDA-resins) specifically designed to achieve the high-yield formation of the covalent linkages (amide or ester bonds) between the substrate and the chiral auxiliary within the NMR tube, without the need for other manipulations, on a microscale level and in a short time. The deuterated NMR solvents (CDCl3, CD3CN, CS2/CD2Cl2) are also the reaction solvents and separations, purifications or workups of any kind are not necessary prior to recording the spectra. The CDA-resins prepared included MPA, 9-AMA, BPG, MTPA, and 2-NTBA as auxiliary agents incorporated either as single enantiomers or as mixed combinations of the (R)- and the (S)-enantiomers at unequal and known ratios. The high versatility of these systems was successfully demonstrated in a variety of ways based on double and single derivatization, low temperature experiments, or the formation of metal complexes. The approach allowed the absolute configurations of chiral primary amines, primary and secondary alcohols, cyanohydrins, thiols, diols, triols, and amino alcohols to be determined. Extensive high-resolution magic angle spinning (HR-MAS) NMR experiments allowed the characterization of the new CDA-resins and enabled the study of their stability and regioselectivity. [ABSTRACT FROM AUTHOR]

Visual-spatial abilities are usually neglected in academic settings, even though several studies have shown that their predictive power in science, technology, engineering, and mathematics domains exceeds that of math and verbal ability. This neglect means that many spatially talented youths are not identified and nurtured, at a great cost to society. In the present work, we aim to identify behavioral and electrophysiological markers associated with visual spatial-ability in intellectually gifted adolescents (N = 15) compared to age-matched controls (N = 15). The participants performed a classic three-dimensional mental rotation task developed by Shepard and Metzler (1971) [33] while event-related potentials were measured in both frontal and parietal regions of interest. While response time was similar in the two groups, gifted subjects performed the test with greater accuracy. There was no indication of interhemispheric asymmetry of ERPs over parietal regions in both groups, although interhemispheric differences were observed in the frontal lobes. Moreover, intelligence quotient and working memory measures predicted variance in ERP's amplitude in the right parietal and frontal hemispheres. We conclude that while gifted adolescents do not display a different pattern of electroencephalographic activity over the parietal cortex while performing the mental rotation task, their performance is correlated with the amplitude of ERPs in the frontal cortex during the execution of this task. [ABSTRACT FROM AUTHOR]

Suggests changes to the flawed approach of the World Health Report 2000. Concern about data availability, as well as the methods for determining health-system responsiveness, health distribution and inequalities; Flaws in the definition of fair financing; Methodological limitations and controversies; Use of relevant publications; Controversies about the measure of health status; Concerns about the multi-component indices used; Policy context of measurement issues; Conclusion.