Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

Ag and AgxO thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the AgxO thin film showed both metallic Ag and Ag-O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while AgxO layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and AgxO surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to AgxO coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology were pointed as the main factors in the origin of the antibacterial effect found in AgxO thin film. The present study demonstrated that AgxO coating presented antibacterial behavior and its application in cardiovascular stents is promising.

Fabrication and characterisation of ferroelectric lead zirconate titanate and strontium bismuth tantalate thin films

Ferroelectrics, liquid delivery, MOCVD, lead zirconate titanate, strontium bismuth tantalate

Free-standing smectic liquid crystal elastomer films

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2010

Modeling of micro- and nanostructures made of films and crystals/fibers arrays

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2013

The diamond : a study in Chinese and Hellenistic folk-lore / by Berthold Laufer --

v.15:no.1(1915)

Condensation of polyhedric structures onto soap films

We study the existence of solutions to general measure-minimization problems over topological classes that are stable under localized Lipschitz homotopy, including the standard Plateau problem without the need for restrictive assumptions such as orientability or even rectifiability of surfaces. In case of problems over an open and bounded domain we establish the existence of a “minimal candidate”, obtained as the limit for the local Hausdorff convergence of a minimizing sequence for which the measure is lower-semicontinuous. Although we do not give a way to control the topological constraint when taking limit yet— except for some examples of topological classes preserving local separation or for periodic two-dimensional sets — we prove that this candidate is an Almgren-minimal set. Thus, using regularity results such as Jean Taylor’s theorem, this could be a way to find solutions to the above minimization problems under a generic setup in arbitrary dimension and codimension.

The Quest for Regulating the Global Diamond Trade

Campaign efforts by NGOs initially put conflict diamonds on the global radar screen in the late 1990s. In response, the Kimberley Process (KP), a negotiation forum between states, NGOs, and industry, was formed to discuss possible solutions to curb the trade in conflict diamonds. Less than three years later, a voluntary, global certification named the Kimberley Process Certification Scheme (KPCS) was adopted. The KPCS regulates the trade of rough diamonds by certifying all legitimate diamonds. This paper outlines the problem of conflict diamonds, how a global campaign raised awareness about the issue, and how the process of solution building unfolded in the KP. My analysis focuses on the diverse set of actors (NGOs, states, and industry) and their changing interactions over the course of the campaign and global regulation efforts. I conclude with several key lessons that capture important elements observed in this case study.

Determination of chemical composition and its relationship with optical properties of Ti-N and Ti-V-N sputtered thin films

In the investigation of thin films of transition metal nitrides, an essential role is played by the accurate determination of their chemical composition. Actually the chemical composition depends on the deposition parameters and influences the optical properties. These relations are illustrated in thin films of TiNx and (Ti1-yVy)N-x deposited by reactive magnetron sputtering from composite targets of the elements. By variation of the nitrogen partial pressure and the target composition, different samples have been obtained. The chemical composition has been measured by electron probe microanalysis at low irradiation voltages. The optical properties are evaluated by ex-situ ellipsometry. Using the screened Drude model, they are correlated with the differences in composition. Adding vanadium or nitrogen in Ti-N is shown to have the same effect on the optical properties.

Cinéma, machine à mondes : essai sur les films à univers multiples

Dans cet ouvrage, l'auteur propose une conceptualisation théorique de la coprésence en un même film de mondes multiples en abordant différents paramètres (hétérogénéité de la facture de l'image, pratiques du montage alterné, typologie des enchâssements, expansion sérielle, etc.) sur la base d'un corpus de films de fiction récents qui appartiennent pour la plupart au genre de la science-fiction (Matrix, Dark City, Avalon, Resident Evil, Avatar,...). Issue de la filmologie, la notion de « diégèse » y est développée à la fois dans le potentiel d'autonomisation dont témoigne la conception mondaine qui semble dominer aujourd'hui à l'ère des jeux vidéo, dans ses liens avec le récit et dans une perspective intermédiale. Les films discutés ont la particularité de mettre en scène des machines permettant aux personnages de passer d'un monde à l'autre : les modes de figuration de ces technologies sont investigués en lien avec les imaginaires du dispositif cinématographique et les potentialité du montage. La comparaison entre les films (Tron et son récent sequel, Totall Recall et son remake) et entre des oeuvres filmiques et littéraires (en particulier les nouvelles de Philip K. Dick et Simlacron 3 de Galouye) constitue un outil d'analyse permettant de saisir la contemporanéité de cette problématique, envisagée sur le plan esthétique dans le contexte de l'imagerie numérique.