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AIM: The present cross-sectional survey was performed to determine cephalometric standards in a large sample (n. 1071) of children from Southern Italy (Naples). MATERIALS AND METHODS: 1071 lateral cephalograms of healthy children, between 8 to 12 years, with various types of occlusion, all with no history of orthodontic treatment before cephalometric analysis were examined. Seven angular and three linear length measurements (SNA, SNB, ANB, SN^GoMe, PN^Pal I^SN, i^GoMe), and three ratios were included. Descriptive statistics, including the mean, standard deviation, and maximum and minimum, values was computed for each cephalometric variable. RESULTS: Changes in angular and linear parameters during the observation period occurred mostly between the ages of 10 and 12 years. The three ratios varied from age and were not characterised by a progressive rise in mean values. Se-N/Go-Pg was greater in 11-year-old boys (p <0.05) and 12-year-old boys (p <0.01); the cranio-maxillary index Se-N/PNS-A1 was greater in 9-year-old girls (p <0.05), whereas the maxilla-mandibular index PNS-A1/Go-Pg was greater in 9-year-old boys (p <0.01). CONCLUSION: The findings provided useful reference cephalometric normative measures for the 8-to-12-year-old Southern Italian children population. Significant differences between boys and girls in the length of the anterior cranial base and ratio were reported.

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We have experimentally observed the biaxial switching between two topologically distinct textures of a nematic liquid crystal cell submitted to a strong electric field. The effect is deduced from optical and electrical measurements across the cell. Above a static threshold, a bulk order reconstruction is observed, where the final nematic orientation in the centre becomes perpendicular to its initial one, inducing a total pi change of orientation across the cell. Using short electric field pulses, a higher dynamical threshold is observed. These experiments are explained by a Landau-de Gennes-Khalatnikov model. The threshold implies the local exchange of two eigenvalues of the nematic order tensor through intermediate biaxial states. The onset of the effect in a thin splay-bend wall decreases the static threshold by almost an order of magnitude. The model explains reasonably well the static and dynamic measurements within the present description of nematic biaxiality.

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A statistical approach for the nematic order on an orienting photopolymer, also taking into account the surface anisotropy, has been formulated in the framework of mean field theory. This approach gives a Boltzmann-type orientational distribution function depending on both nematic-nematic and nematic-polymer interaction energies. The azimuthal anchoring energy coefficient has been evaluated from the extra Helmholtz free energy within an interface of thickness xi that may be interpreted as the length over which the density changes from pure polymer to pure liquid crystal or, generally speaking, as the typical length over which the interaction between polymer and liquid crystal takes place. In the case of surface anisotropy given by linearly polarized UV photopolymerization, the anchoring energy coefficient depends on the exposure time and on xi.

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The variations of lymphocyte subsets in chronic inflammatory and neoplastic diseases in an elderly population, have been previously reported. The different behavior of all the subsets that had shown significant variations of frequencies and absolute values within the groups with the Multivariate Analysis of Variance, have been studied. The use of the Discriminant Stepwise Analysis has given the chance to spot the discriminant subsets and their ability in discriminating the inflammatory and the neoplastic groups from each other and from the controls and finally in pointing out all the subsets which did not affect such differentiation.

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