Evaluation of imperfections in silica and chalcogenide glass microspheres using focussed ion beam milling and imaging.

Microspheres made from optical glasses such as silica and chalcogenide are used as both passive and active optical elements in micro-optics systems and devices. The homogeneity of the microspheres is crucial to their optical quality and performance in such devices and so it is essential, in optimizing such systems, that techniques with nanometer scale resolution are developed to measure the internal structure and homogeneity of such spheres. In this work an analytical protocol based on focussed ion beam milling, combined with secondary ion and secondary electron imaging, has been developed to study the internal homogeneity of glass microspheres. The results have shown that silica microspheres with diameters of three to five microns, fabricated by a sol-gel method, have internal inhomogeneities and voids that will lead to non-uniform optical properties. The FIB milling and imaging technique developed has been found to be a very useful method of studying such inhomogeneities, which have been proposed, but never previously observed, in glass microspheres. The FIB based technique has also been used on larger chalcogenide glass (Ga(2)S(3):La(2)S(3)) microspheres (diameter of order 70 microns) but no inhomogeneities have been observed at the spatial resolution of a few microns so far achieved for these larger microspheres. This study suggests that the FIB based milling and imaging technique may have potential for quantitative use in the measurement of morphological variations in such systems as well as in the study of aging processes in micron-sized glass spheres.

Multi-analytical study of patination methods on steel substrates: a full insight into surface chemistry and morphology.

Patination of metals has been used for decorative or protective purposes, and several methods aimed to create coloured films on metal surfaces have been developed. This work describes a multi-analytical approach to characterize artificial blue patinas created on mild steel substrates by means of traditional recipes and methods for colouring ancient objects and artefacts. We suggest the combined use of secondary ion mass spectrometry, focused ion beam, X-ray diffraction spectroscopy, white light interferometry and reflectance spectroscopy to characterize blue patinas on steel substrates and to investigate the relationship between the developed colour and the patina layer microstructure and composition. Therefore, the analysis of the oxide films produced by either thermal or chemical colouring methods has been successfully performed, providing information about the film morphology, the surface composition and in-depth elemental distribution within the coloured layers, and the origin of the colour developed on the surface.

Mutational heterogeneity in low-density lipoprotein receptor gene related to familial hypercholesterolemia in Morocco.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Until now, molecular data concerning FH in Morocco is still limited. To gain more information in this field and to assess the contribution of these three genes in the cause of FH determinism, we analyzed six unrelated Moroccan probands and twenty-five of their family's members. METHODS: After LDLR and APOB genotype analysis, we screened the LDLR gene for mutations using southern blot and PCR-sequencing analysis. We also screened the APOB gene for the two common mutations R3500Q and R3531C by PCR-mediated site-directed mutagenesis. The PCSK9 gene was analyzed by direct sequencing. RESULTS: We identified three novel mutations (C25X, IVS3+5G>T, D558A) and two mutations previously described (D151N, A480E) in the LDLR gene. The R3500Q and R3531C mutations are absent in our probands and for 1 proband, the implication of LDLR, APOB and PCSK9 genes was excluded, supporting the implication of a fourth gene in the determination of FH. CONCLUSION: These data are in agreement with our previous study that suggests a heterogeneous mutational spectrum of FH in Morocco.

Children into DSM don't go: a comparison of classification systems for eating disorders in childhood and early adolescence.

OBJECTIVE: To evaluate the reliability of diagnostic classification systems for eating disorders when applied to children and young adolescents. METHOD: Eighty-one patients were randomly selected from a population of 226 children (age 7-16) presenting with eating difficulties to a specialist clinic. Diagnoses were assigned according to three classification systems: the 10th edition of the International Classification of Diseases (ICD 10), the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), and Great Ormond Street (GOS) criteria. Ratings were performed by two clinicians blind to the diagnosis of the other. RESULTS: Interrater reliability values (kappa) for the three systems were 0.357 (ICD 10), 0.636 (DSM-IV), and 0.879 (GOS). Using DSM criteria, more than 50% of children were classified as eating disorder not otherwise classified (EDNOS) or could not be classified. DISCUSSION: DSM-IV and ICD 10 criteria are of little value in the classification of the eating difficulties of children. The GOS criteria, which were developed for this age range, are more reliable. The classification of eating disorders in childhood needs reevaluation.