Depth profile analyses of nc-TiC/a-C:H coating prepared by balanced magnetron sputtering

Nanocrystalline titanium carbide embedded in an hydrogenated amorphous carbon matrix (nc-TiC/a-C:H) shows high hardness and Young's modulus together with low wear and low friction coefficient. In this paper, we report on the preparation of well adherent nc-TiC/a-C:H coatings ~ 5 μm thick on stainless steel substrates using a well balanced magnetic field configuration and only very low power RF bias on the substrate. Hardness and Young's modulus of these coatings are 43 GPa and 380 GPa, respectively. The mechanical properties – hardness and Young's modulus – measured from the coating's top reach the values obtained at optimized experiments where the unbalanced magnetic field configuration was used. A simple method of depth profiling suitable for evaluation of mechanical properties of several micrometers thick coatings is developed and employed. The paper reports on the depth profile analyses of the coating hardness, Young's modulus, composition and morphology.     

Chemical and Textural Characterization of Iron Oxide Nanoparticles and Their Effect on the Thermal Decomposition of Ammonium Perchlorate

Metal oxide nanoparticles have been used as burning rate catalysts for ammonium perchlorate (AP) decomposition in composite solid propellants. Though most papers point to the efficiency of different sizes, shapes and compositions, the texture of the agglomerated particles plays an important role in the catalytic efficiency, but this aspect is not always discussed. In this paper, iron oxide and composite iron oxide/silica powders were synthesized in microemulsion systems and their effect on the decomposition of AP was investigated. X‐ray diffraction (XRD) analysis and Fourier transformed infrared spectroscopy (FT‐IR) showed that the synthesized powders have an amorphous to nanocrystalline pattern, with Fe₂O₃ composition. The use of different FT‐IR spectroscopic techniques – transmission, diffuse reflectance (DRIFT) and universal attenuated total reflectance (UATR) – allied to electron microscopy analysis allowed the characterization of the samples’ surface, indicating that silicon oxide forms a thick matrix that covers the iron oxide nanoparticles. Adsorption of N₂, light scattering and electron microscopy pointed that all samples are formed by mesoporous agglomerated nanoparticles containing micropores indicating that silicon oxide forms a thick matrix that covers the iron oxide nanoparticles. Adsorption of N₂, pointed that all samples show different microstructures and light scattering indicated results refer to agglomerated particles. Finally, the catalytic effect of the samples on the decomposition of AP was evaluated by thermogravimetric analysis coupled to differential thermal analysis (TG/DTA), showing that only the high temperature decomposition step of AP was affected by the catalyst, shifting to lower temperatures the higher the surface area of the synthesized iron oxide sample, regardless of the presence of the silica matrix.     

Antiproliferative and Pro-Apoptotic Effect of Novel Nitro-Substituted Hydroxynaphthanilides on Human Cancer Cell Lines

Ring-substituted hydroxynaphthanilides are considered as cyclic analogues of salicylanilides, compounds possessing a wide range of pharmacological activities, including promising anticancer properties. The aim of this study was to evaluate the potential anticancer effect of novel nitro-substituted hydroxynaphthanilides with a special focus on structure-activity relationships. The antiproliferative effect was assessed by Water Soluble Tetrazolium Salts-1 (WST-1) assay, and cytotoxicity was evaluated via dye exclusion test. Flow cytometry was used for cell cycle analysis and detection of apoptosis using Annexin V-FITC/PI assay. Protein expression was estimated by Western blotting. Our data indicate that the potential to cause the antiproliferative effect increases with the shift of the nitro substituent from the ortho- to the para-position. The most potent compounds, 3-hydroxy-N-(3-nitrophenyl)naphthalene-2-carboxamide (2), and 2-hydroxy-N-(4-nitrophenyl)-naphthalene-1-carboxamide (6) showed antiproliferative activity against THP-1 and MCF-7 cancer cells without affecting the proliferation of 3T3-L1 non-tumour cells. Compounds 2 and 6 induced the accumulation of THP-1 and MCF-7 cells in G1 phase associated with the downregulation of cyclin E1 protein levels, while the levels of cyclin B1 were not affected. Moreover, compound 2 was found to exert the pro-apoptotic effect on the THP-1 cells. These results suggest that hydroxynaphthanilides might represent a potential model structure for the development of novel anticancer agents.     

Methodology to break test for surfactant-based fracturing gel

Surfactant-based fracturing gels are considered as clean gels due to the absence of insoluble residues in their composition. This kind of fluid has been developed to minimize or eliminate damages to fractures. In view of this, new studies about properties of this kind of gel have become more and more important. Gel break is an important parameter for hydraulic fracturing gels. This research was carried out with the purpose of developing a laboratory break methodology for surfactant-based fracturing gel. It was observed that the studied gel presented optimum break results, due to a viscosity decrease to 10 mPa s in the first 6 h of the test.     

Phenanthrene and pyrene oxidation in contaminated soils using Fenton's reagent

Fenton's reagent has shown its applicability to oxidizing these biorefractory organic contaminants. The purpose of this contribution was to investigate the influence of operating parameters on the process efficiency for soil highly contaminated by PAHs. Five variables were selected: pH, reaction time, UV irradiation, hydrogen peroxide concentration and Fe (II) amendment. Their effects on the oxidation of (i) phenanthrene and on (ii) phenanthrene and pyrene present in freshly contaminated soil samples were studied through batch reactor experiments following factorial designs. For phenanthrene oxidation run with a soil contaminated at 700 mg kg(-1), one set of variables enabled us to reach a residual concentration lower than 40 mg kg(-1) (Dutch legislation threshold). The most important factor was the reaction time, followed at a certain distance by UV irradiation, Fe (II), H(2)O(2) concentration and pH, this last variable being the least significant. The possibility of operating without pH adjustment is of importance in the treatment at the field scale. This shows the feasibility of photo-Fenton-like oxidation for the treatment of soil highly contaminated with PAH and the relative importance of the process variables.     

Linear covariant gauges on the lattice

Linear covariant gauges, such as Feynman gauge, are very useful in perturbative calculations. Their non-perturbative formulation is, however, highly non-trivial. In particular, it is a challenge to define linear covariant gauges on a lattice. We consider a class of gauges in lattice gauge theory that coincides with the perturbative definition of linear covariant gauges in the formal continuum limit. The corresponding gauge-fixing procedure is described and analyzed in detail, with an application to the pure SU(2) case. In addition, results for the gluon propagator in the two-dimensional case are given.     

Virtual reality authoring for schools

The paper describes a method for programming behaviours of objects in virtual worlds. It is designed to be easy to use and to shield users from complex coding and syntax errors. It has been tested in a number of projects within schools in Brazil.     

Improvement of the Detection Sensitivity for <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> in Spices and Herbs

Various variants of ISO 6888-1:1999 and ISO 6888-3:2003 methods for the detection of Staphylococcus aureus were evaluated and improved for their application to conduct analysis in spices and herbs. Improvement substantiated in washing of the sample to remove compounds interfering with the analysis and in the use of PCR for final detection, instead of plating on Baird-Parker agar, to improve sensitivity at high backgrounds and to save time. The evaluation of the method variants was based on determination of the detection limit (LOD) using series of artificially contaminated spices (allspice, black pepper, cinnamon, nutmeg, paprika, vanilla) and herbs (basil, oregano, parsley, thyme). The method without enrichment, ISO 6888-1:1999, produced LODs of 10³–10⁵ CFU/g with no positive effect of washing the sample or use of PCR for final detection. The method with enrichment, ISO 6888-3:2003, had LOD of 10⁰ CFU/g for basil, black pepper, paprika and parsley. If the washing step was added and PCR was used for final detection, LOD of 10⁰ CFU/g was determined also for cinnamon, nutmeg and vanilla, and LOD of 10¹ CFU/g was determined for allspice. For oregano and thyme, which strongly inhibit the growth of S. aureus, an alternative enrichment-independent method based on direct DNA extraction coupled to real-time PCR may be advantageous.     

Der Bazar der Anforderungen

Traditionelles Requirements Engineering ist auf die Ermittlung, Festschreibung und Nachvollziehbarkeit von Anforderungen in den Informationssystemen einer Organisation fokussiert. Die fortschreitende Globalisierung und Vernetzung hat neue Formen der Zusammenarbeit und der informationstechnischen Unterstützung hervorgebracht. Auf Basis von zwei Fallstudien zu offenen Innovationsprozessen haben wir die Anforderungen an ein adaptives Requirements Engineering für emergente Communities ermittelt. Zur informatischen Unterstützung haben wir ein i*-Modell für die Beschreibung der wechselseitigen Abh?ngigkeiten zwischen den Communities und den von ihnen genutzten Informationssystemen aus der Sichtweise des adaptiven RE entwickelt. Wir unterstützen das adaptive RE durch einen Dienstbaukasten, der in die zu entwickelnden Informationssysteme integriert werden kann. Dadurch entsteht im Sinne der Open-Source-Bewegung ein Bazar von Anforderungen. Diesen Vorgang haben wir prototypisch in einen Store für webbasierte Widgets zur Gestaltung von personalisierten Lernumgebungen umgesetzt.