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The surface chemical and physical modifications of poly(ethylene terephthalate) (PET) fibers induced by radiofrequency air plasma treatments were correlated with the characteristics of the discharge parameters and the chemical composition of the plasma itself, to identify the plasma-induced surface processes prevailing under different operating conditions. Treated polymer surfaces were characterized by water droplet absorption time measurements and XPS analysis, as a function of the aging time in different media, and by AFM analysis. They exhibited a remarkable increase in hydrophilicity, accompanied by extensive etching and by the implantation of both oxygen- and nitrogen-containing polar groups. Etching was mainly a consequence of ion bombardment, yielding low molecular weight, water soluble oxidation products, while surface chemical modifications were mainly due to the action of neutral species on the plasma-activated polymer surface. (C) 2003 Elsevier Science B.V. All rights reserved.

Here we report a genome-wide association study for non-pathological pinna morphology in over 5,000 Latin Americans. We find genome-wide significant association at seven genomic regions affecting: lobe size and attachment, folding of antihelix, helix rolling, ear protrusion and antitragus size (linear regression P values 2 × 10(-8) to 3 × 10(-14)). Four traits are associated with a functional variant in the Ectodysplasin A receptor (EDAR) gene, a key regulator of embryonic skin appendage development. We confirm expression of Edar in the developing mouse ear and that Edar-deficient mice have an abnormally shaped pinna. Two traits are associated with SNPs in a region overlapping the T-Box Protein 15 (TBX15) gene, a major determinant of mouse skeletal development. Strongest association in this region is observed for SNP rs17023457 located in an evolutionarily conserved binding site for the transcription factor Cartilage paired-class homeoprotein 1 (CART1), and we confirm that rs17023457 alters in vitro binding of CART1.

The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.

Il rapporto tra ontologia e tecnologia trova le sue radici nell'etimologia dei due termini, di derivazione greca, cioè discorso sull'essere e discorso sull'arte. Entrambi si occupano di trovare metodi di rappresentazione di saperi che si instanzino in un saper fare, così come a livello informatico si declina in una rappresentazione formale della conoscenza. Nel contributo si approfondisce il tema della interfacce cognitive e della rappresentazione del sapere attraverso l'analisi degli esiti della sperimentazione di due ambienti on line dedicati alla gestione e rappresentazione di ontologie web

Surface modification of poly(ethylene terephthalate) (PET) fabrics induced by air radiofrequency (RF) plasma treatment has been investigated systematically as a function of plasma device parameters, to identify the plasma-polymer surface interactions prevailing under different operating conditions and leading to an increased color depth upon dyeing. Some tests have also been performed employing chemically inert argon as a feedstock gas. The dyeing properties of plasma-treated fibers were correlated to their topographical characteristics, determined by AFM analysis, and to their chemical surface composition, determined by XPS analysis, while the plasma-originated UV radiation was found to have no relevant effects in PET surface modification. The relative importance of plasma-induced surface processes, such as etching and grafting of polar species, is discussed in relation to their role in modifying PET dyeing properties. (c) 2005 Elsevier B.V. All rights reserved.

Surface modification induced on poly(ethylene terephthalate) (PET) fibres by cold SF6 plasma treatment has been investigated systematically as a function of plasma device parameters. The observed wettability modifications of fibres plasma treated under different operating conditions were correlated to their dyeability modifications and to the changes in surface chemical composition, determined by X-ray photoelectron spectroscopy (XPS), and in topography, investigated by atomic force microscopy (AFM). Optical emission spectra from the SF6 plasma at different pressure gave information on its content of fluorine atoms. A striking transition was observed between increased hydrophilicity and high dyeability, imparted by plasma treatment at low pressure, mainly as a consequence of surface etching and surface activation, and increased hydrophobicity, imparted by plasma treatment in the higher pressure regime (0.2-0.4 mbar), consequent to extended surface fluorination.

Linee metodologiche per la elaborazione di una ontologia della comunicazione educativa

Plasma treatments are used to modify surface properties of materials such as adhesivity, hydrophobicity, oleophobicity, hydrophilicity. The plasma interaction with the surface produces modifications of its chemical structure and morphology. The present work shows the surface modification of polyethylene terephthalate film (PET) after the exposure to an atmospheric pressure air dielectric barrier discharge (DBD). The treated surface has been analyzed using atomic force microscopy (AFM) and contact angle measurement. AFM analysis show roughness changes in both amplitude and peaks spacing: surface modifications cause both optical properties changes and adhesivity enhancement to coating and depositions.

Soft X-ray Contact Microscopy (SXCM) of Caenorhabditis elegans nematodes with typical length similar to 800 mum and diameter similar to 30 mum has been performed using the PALS laser source of wavelength lambda = 1.314 mum and pulse duration tau ( FWHM) = 400 ps. Pulsed soft X-rays were generated using molybdenum and gold targets with laser intensities I greater than or equal to 10(14) W/cm(2). Images have been recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Cuticle features and several internal organs have been identified in the SXCM images including lateral field, cuticle annuli, pharynx, and hypodermal and neuronal cell nuclei.

Soft X-ray Contact Microscopy (SXCM) experiments have been performed on the nematode Caenorhabditis elegans using the Prague Asterix Iodine Laser System (PALS). Pulsed X-rays were generated using gold and molybdenum targets with laser intensities 1 greater than or equal to 10(14) W/cm(2) to record the contact images of C. elegans on PMMA photoresists. Results were analyzed using an atomic force microscope operating in constant force mode. Our results show some characteristic features of the C. elegans and the suitability of the sxcm technique for the study of multi-cellular specimens.

Some selective cold plasma processing modify specific surface properties of textile polymeric materials such as their dyeability, wettability and hydrorepellence. To correlate the sample surface changes with the acquired surface properties allows one to obtain information on the chemical and physical processing involved in plasma treatment. In this work, atomic force microscopy (AFM) has been applied to investigate the morphological and topographical surface modifications induced by RF cold plasma processing of poly(ethyleneterephthalate) (PET) fabrics. Rms surface roughness and surface area of the samples are measured before and after the treatments. The morphology changes have been analysed as a function of the treatment time and air gas pressure. Measurements have been performed also using plasmas produced by different gases such as He, Ar, SF6, and CF4. The PET shows different behaviour with different gas plasmas. In the case of air, He and Ar gases the sample surface modifications seem to be mainly due to etching effects, while the fluorine atoms grafting probably is responsible for surface rearrangement process using SF6 and CF4 gases. As a consequence different surface properties are produced in the plasma treated samples.

Some selective plasma treatments are described, aiming at modifying specific surface properties of textile polymeric materials, such as their hydrorepellence and dyeability. The prevailing plasma–polymer interactions were identified by correlating the physico-chemical modification of treated polymer surfaces to the characteristics of the plasma sources.

Atomic force microscopy (AFM) has been used to investigate the morphology changes in the surface of poly(ethyleneterephthalate) (PET) fabrics due to cold plasma treatments. This has resulted in the possibility to measure quantitatively the root-mean-square (rms) surface roughness and the surface area of the samples developed after the treatment. The morphology changes, mainly rms surface roughness and surface area, on the PET fabrics surface due to air cold plasma have been measured as a function of treatment time and as a function of gas pressure. The same quantities as a function of pressure were measured also for He, Ar, SF 6 and CF 4 gases. The changes in morphology in the cases of air, He and Ar gases seems to be due mainly to etching effects. The situation is different for SF 6 and CF 4 gases where reorganisation of the surface, possibly due to fluorine atoms grafting, seems to be effective. © 2003 Elsevier B.V. All rights rerserved.

Atomic force microscopy (AFM) has been applied to investigate the morphological and topographical surface modifications induced by radiofrequency cold plasma processing of poly (ethyleneterephthalate) textiles. Surface effects are analysed in low-pressure air plasma for different plasma exposure times. The results show a progressive degradation of the surface with increasing roughness. The analysis suggests that modification of the surface during textile treatment may be ascribed to a plasma-induced physical process. Copyright (C) 2003 John Wiley Sons, Ltd.

In this paper the results of an experiment on soft X-ray contact microscopy using a laser-plasma source are presented. A resolution of 50 nm has been achieved imaging pig sperm cells, while other specimens, such as algae and yeast cells, showed internal details, proving the technique to be a powerful tool for biological investigations. Original biological information has been obtained and the conditions for optimal image formation have been studied

The use of a high energy laser source for Soft X-Ray Contact Microscopy (SXCM) is discussed. Different targets have been used and their emission spectra recorded and compared inside and outside the Water Window spectral region. Up to twelve sample holders per shot have been exposed, thanks to the large X-ray flux and the geometry of the interaction chamber. Images of biological samples have been obtained, including Chlamydomonas, Phytomonas, Saccaromyces Cerevisiae yeast cells and pig sperm. A 50 nm resolution has been achieved and original biological information concerning the inner structure of the cells has been obtained.