Enantiosensitive growth dynamics of chiral molecules on ferromagnetic substrates and the origin of the CISS effect.

The recent demonstration of the existence of an intimate relationship between the chiral structure of some materials and the spin polarization of electrons transmitted through them, what has been called the chirality-induced spin selectivity (CISS) effect, is sparking interest in many related phenomena. One of the most notorious is the possibility of using magnetic materials to apply enantioselective interactions on chiral molecules and chemical reactions involving them. In this work, x-ray photoelectron spectroscopy has been used to characterize the adsorption and growth kinetics of enantiopure organic molecules on magnetic (Co) and non-magnetic (Cu) substrates. While on these latter, no significant enantiosensitive effects are found, on spin-polarized, in-plane magnetized Co surfaces, the two enantiomers have been found to deposit differently. The observed effects have been interpreted as the result of one of the enantiomers being adsorbed in a transient, weakly bound physisorbed-like state with higher mobility due to limited, spin-selective charge transfer between it and the substrate. The study of these phenomena can provide insight into the fundamental mechanisms responsible for the CISS effect.

Cu diffusion as an alternative method for nanopatterned CuTCNQ film growth.

In this paper we show by means of 'in situ' x-ray diffraction studies that CuTCNQ formation from Cu(solid)-TCNQ(solid tetracyanoquinodimethane) goes through Cu diffusion at room temperature. The film quality depends on the TCNQ evaporation rate. At low evaporation rate we get a single phase-I CuTCNQ film very well crystallized and well oriented. The film has a CuTCNQ(0 2 0) orientation. The film is formed by CuTCNQ nanorods of a very homogeneous size. The film homogeneity has also been seen by atomic force microscopy (AFM). The electronic properties of the film have been measured by x-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). Thus, the Cu-diffusion method has arisen as a very simple, clean and efficient method to grow localized CuTCNQ nanorods on Cu, opening up new insights for technological applications.

Numerically efficient real space theory of scattering from colloidal crystals.

The production of high-quality colloidal crystals demands precise quantitative characterization of their nanostructures. While small-angle radiation scattering is the technique of choice, a procedure for a comprehensive quantitative modeling of the data is still pending. A novel theory based on the pertinent radial pair distribution which takes into account orientational, positional, stacking disorder and grain effects is developed here. We also show how the scattering length density of the particles can be estimated from the positions of minima in the form factor. The obtained results can be cast as sums of analytical functions over the distribution function and, as such, are suitable for easy (automatic) parallelization. On the experimental side, we report on a strong extinction effect coming from grazing incidence specular reflection that we have been able to model analytically.

Psychometric properties of the Spanish version of the Eating Behaviours and Body Image Test for Preadolescent Girls (EBBIT).

The purpose of the current study was to explore the psychometric properties of the Spanish adaptation of the Eating Behaviours and Body Image Test for Preadolescent Girls (EBBIT), as well as its factor structure and internal consistency. A further objective was to determinate the convergent validity between measures of body mass index (BMI) and scores on the Body Dissatisfaction (BD) subscale, taking into account a wider questionnaire, known as the Eating Disorders Inventory (EDI-2). Once the original scale was translated, 525 girls (age range 7-12 years) were assessed by the EBBIT, and the BD subscale. Students were weighed and measured, using calibrated electronic instruments to calculate BMI scores. Factor analysis suggested two primary factors which represent body image dissatisfaction/ restrictive eating (BIDRE) and binge eating behaviours (BEB). The internal consistency of the EBBIT was 0.904. A multiple regression analysis was performed using BMI, age and BD subscale data (independent variables). Results suggest that scores on the EBBIT factors are related to body size satisfaction. Higher BMI and higher BD scores were associated with higher scores on the BIDRE, and BD scores were associated with higher scores on the BEB factor.

Molecular structure-dynamics relationships in glassy poly(isophthalamide)s as revealed by wide angle x-ray scattering, dielectric loss spectroscopy, and molecular modelling.

The effect of molecular structure on the gamma relaxation dynamics has been studied in a set of aromatic poly(isophthalamide)s. This polymer family differ in the bridge group between phenylene rings [hexafluoroisopropylidene (C(CF(3))(2)) or ether] and also in the presence of t-butyl groups (C(CH(3))(3)) as pendant substituent on the five position of isophthalic ring. The results obtained from wide angle x-ray scattering in the glassy state indicated that both (C(CF(3))(2)) and (C(CH(3))(3)) groups favor the separation between chains, which is reflected on different interchain average distances. Dielectric experiments showed that both bulky groups favor the mobility in the glassy state. Molecular modelling methods were used to know the kind of molecular motions associated to the dielectric relaxation observed below the glass transition temperature.