Glyconanoparticle-DNA interactions: an atomic force microscopy study.

Glyconanoparticles which present carbohydrate and amino groups motifs at their surface were produced. These particles were highly stable and soluble in aqueous solutions. The presence of the carbohydrate groups also allowed the inclusion of more strongly binding groups, without affecting solubility. The binding of a model DNA, plasmid by these nanoparticles was studied by atomic force microscopy, transmission electron microscopy, and gel electrophoresis. Significant differences between the nanoparticles based on their affinities for the DNA were found, with implications for their potential use as nonviral gene delivery agents.     

Development and evaluation of antimicrobial natamycin‐incorporated film in gorgonzola cheese conservation

Conservation of food products depends on product quality and packaging suitability. The objective of this work was to develop and evaluate the antimicrobial efficiency of natamycin‐incorporated film in the production process of Gorgonzola cheese. It aims to optimize the production process and increase shelf‐life and food safety for the consumer. Films with different concentrations of natamycin were produced and tested in Gorgonzola cheeses to evaluate its efficiency against Penicillium roqueforti on the cheese surface. Films with 2 and 4% natamycin presented satisfactory results for fungus inhibition and the amount of natamycin released to the cheese was below that allowed by the legislation. Copyright © 2006 John Wiley & Sons, Ltd.     

Optical and electrical characterization of fluorine doped cadmium oxide thin films prepared by the sol-gel method

Highly transparent and conducting fluorine (F) doped cadmium oxide (CdO) thin films were deposited on glass slides by the sol-gel method. The films were doped by the addition of ammonium fluoride to the precursor solution whose optimum concentration was determined. The films were fired in an open atmosphere at 350 °C and after that, exposed to annealing treatments in different atmospheres (N₂, N₂/H₂ mixture and Ar) at the same temperature. The films were characterized by ultraviolet-visible spectroscopy, X‐ray diffraction and scanning electron microscopy. The resistivity was determined by the four probes method and current-voltage measurements in accordance with the standard Van der Pauw configuration. The CdO:F thin films obtained, showed high polycrystalline quality and high transmission in the visible region (≥ 90%), shifting towards the blue region of the absorption edge as the fluorine concentration in the precursor solution was increased from 0 to 30 at.%. The lowest resistivity values were reached for the samples with F content higher or equal to 5% and annealed in either N₂ or a 96/4 N₂/H₂ gas mixture. Our resistivity value reached in the CdO:F layers was 4.5 × 10^{− 4} Ω cm (20 Ω/square).     

Stages of surface erosion under ion irradiation

Initial stages of surface erosion have been studied for NaCl and LiF single crystals bombarded by Ar⁺ ions with 20 keV. For irradiation with doses D=10¹⁰-10¹¹ ions/cm², exoelectron emission has been used, whereas for higher doses, we have used electron microscopy. Two stages of initial surface erosion have been identified; for small doses, there is slow development of atomic-scale roughening, which reaches its peak when areas damaged by closest incident ions start to overlap, and then, beginning with D=10¹⁶ ions/cm², there is rapid etching, deep into the crystal, followed by the emergence of secondary microscopic structure, i.e. caverns, concentric closed steps and terraces. Ion-induced surface structure of alkali halide crystals has been shown to depend strongly on the presence of foreign particles on the surface, as well as on segregation. Topography of thin carbon films and some metals have been discussed.     

Why are Websites co-linked? The case of Canadian universities

This study examined why Websites were co-linked using Canadian university Websites as the test set. Pages that co-linked to these university Websites were located using Yahool. A random sample of 859 co-linking pages (the page that initiated the co-link) was retrieved and the contents of the page, as well as the context of the link, were manually examined to record the following variables: language, country, type of Website, and the reasons for co-linking. The study found that in over 94% of cases, the two co-linked universities were related academically; many of these cases (38%) showed a relationship specifically in teaching or research. This confirms results, from previous quantitative studies, that Web co-links can be a measure of the similarity or relatedness of sites being co-linked and that Web co-link analysis can thus be used to study relationships among linked Websites.     

Metric analysis of the information visibility and diffusion about the European Higher Education Area on Spanish University websites

The purpose of the study proposed in this paper is to evaluate the Spanish public university websites dedicated to the European Higher Education Area (EHEA). To do so, the quality of these resources has been analysed in the light of data provided by a series of indicators grouped in seven criteria, most of which were used to determine what information is made available and in what way. The criteria used in our analysis are: visibility, authority, updatedness, accesibility, correctness and completeness, quality assessment and navigability. All in all, the results allow us to carry out an overall diagnosis of the situation and also provide us with information about the situation at each university, thus revealing their main strengths, namely authority and navegability, and also their chief shortcomings: updatedness, accessibility and quality assessment. In this way it is possible to detect the best practices in each of the aspects evaluated so that they can serve as an example and guide for universities with greater deficiencies and thus help them to improve their EHEA websites.     

Monte Carlo Simulations of High-Performance Implant Free In0.3Ga 0.7As Nano-MOSFETs for Low-Power CMOS Applications

The potential performance of implant free heterostructure In_0.3Ga_0.7As channel MOSFETs with gate lengths of 30, 20, and 15 nm is investigated using state-of-the-art Monte Carlo (MC) device simulations. The simulations are carefully calibrated against the electron mobility and sheet density measured on fabricated III-V MOSFET structures with a high-kappa dielectric. The MC simulations show that the 30 nm gate length implant free MOSFET can deliver a drive current of 2174 muA/mum at 0.7 V supply voltage. The drive current increases to 2542 muA/mum in the 20 nm gate length device, saturating at 2535 muA/mum in the 15 nm gate length one. When quantum confinement corrections are included into MC simulations, they have a negligible effect on the drive current in the 30 and 20 nm gate length transistors but lower the 15 nm gate length device drive current at 0.7 V supply voltage by 10%. When compared to equivalent Si based MOSFETs, the implant free heterostructure MOSFETs can deliver a very high performance at low supply voltage, making them suitable for low-power high-performance CMOS applications     

Unconventional Charge Density Wave Arising from Electron–Phonon Interaction

We report of a theoretical study on quasi-one dimensional unconventional charge density wave (UCDW) driven by electron–phonon interaction. Within mean field theory, we find that the wavevector dependence of the coupling leads to a momentum dependent single particle gap on the Fermi surface. The presence of small energy single particle excitations around the gap nodes significantly changes the optical conductivity compared to the conventional CDW result. In addition to that, the collective phase excitation arising from fluctuation of the order parameter leads to further qualitative changes of the conductivity and results in an effective mass that is nonmonotonic in temperature.      

Detailed Measurements of Nuclear Spin Polarizations in a Single InAlAs Quantum Dot Through Overhauser Shift of Photoluminescence

We investigated optical pumping of nuclear spin polarizations in a single self-assembled In_0.75Al_0.25As/Al_0.3Ga_0.7As quantum dot. The nuclear spin polarization exhibits the abrupt jump and hysteresis in the excitation power dependence at a particular excitation polarization. Measurement of circular polarization rate of the photoluminescence reveals that the abrupt change of the nuclear spin polarization is created mainly by the spin flip-flop process between nuclei and an electron of a positive charged exciton in this single quantum dot. Model calculation explains well the experimentally observed bistable behavior in InAlAs quantum dot. By using this abrupt change, the sign and magnitude of electron and hole g-factors in z-direction are verified.