S. sanguinis adhesion on rough titanium surfaces: Effect of culture media

Bacterial colonization plays a key role in dental implant failure, because they attach directly on implant surface upon implantation. Between different types of bacteria associated with the oral environment, Streptococcus sanguinis is essential in this process since it is an early colonizer. In this work the relationship between titanium surfaces modified by shot blasting treatment and S. sanguinis adhesion; have been studied in approached human mouth environment. Bacteria pre-inoculated with routinary solution were put in contact with titanium samples, shot-blasted with alumina and silicon carbide, and adhesion results were compared with those obtained when bacteria were pre-inoculated with modified artificial saliva medium and on saliva pre-coated titanium samples. Our results showed that bacterial adhesion on titanium samples was influenced by culture conditions. When S. sanguinis was inoculated in routinary culture media, colonies forming unities per square millimeter presented an increment correlated with roughness and surface energy, but separated by the type of particle used during shot-blasting treatment; whereas in modified artificial saliva only a relationship between bacteria adhered and the increment in both roughness and surface energy were observed, regardless of the particle type. Finally, on human saliva pre-coated samples no significant differences were observed among roughness, surface energy or particle.     

Weak mismatch epitaxy and structural Feedback in graphene growth on copper foil

Graphene growth by low-pressure chemical vapor deposition on low cost copper foils shows great promise for large scale applications. It is known that the local crystallography of the foil influences the graphene growth rate. Here we find an epitaxial relationship between graphene and copper foil. Interfacial restructuring between graphene and copper drives the formation of (n10) facets on what is otherwise a mostly Cu(100) surface, and the facets in turn influence the graphene orientations from the onset of growth. Angle resolved photoemission shows that the electronic structure of the graphene is decoupled from the copper indicating a weak interaction between them. Despite this, two preferred orientations of graphene are found, ±8° from the Cu[010] direction, creating a non-uniform distribution of graphene grain boundary misorientation angles. Comparison with the model system of graphene growth on single crystal Cu(110) indicates that this orientational alignment is due to mismatch epitaxy. Despite the differences in symmetry the orientation of the graphene is defined by that of the copper. We expect these observations to not only have importance for controlling and understanding the growth process for graphene on copper, but also to have wider implications for the growth of two-dimensional materials on low cost metal substrates.      

Modelling Interactions Between Lot-Scale Decentralised Water Infrastructure and Urban Form – a Case Study on Infiltration Systems

Modelling the design and implementation of urban water infrastructure (particularly decentralised systems) for strategic planning and policymaking requires detailed information of the spatial environment and quantitative knowledge of social preferences. Currently available models, however, mostly use land use, population and impervious cover data without much regard for detailed urban form or society. This study develops an algorithm for determining urban form from minimal spatial data input by incorporating local planning regulations. The interaction between urban form and implementation of lot-scale infiltration systems under different social, biophysical and climate constraints is then investigated, firstly by looking at how this varies in different residential land uses and subsequently in a case study of a typical Melbourne residential subdivision of mixed land uses. Feasibility of infiltration and its downstream impact (runoff volume, frequency and pollution) were assessed for a range of social preferences (quantified as allowable garden space) and climate scenarios (30 % increase/decrease in rainfall and evapotranspiration). Performance indicators were determined through long-term simulation with the MUSIC software. Results show how different biophysical, planning, social and climate conditions affect infiltration feasibility as well as system performance. High infiltrating soils, for example, allow smaller, well-performing and socially less-imposing systems. Low infiltrating soils lead to larger system sizes, occupy much of the allotment’s garden space, but nevertheless provide the benefit of runoff frequency reduction. Overall, climate impact was not significant except for areas with poorly infiltrating soils. Joint consideration of social, planning, climate and water management aspects potentially allows more efficient policymaking, as an array of system configurations can be tested against different multi-faceted scenarios. Such models can help facilitate better participatory planning and policymaking.     

Development of an intermediate moisture food from bean (Phaseolus vulgaris L.)

Beans consumption has been associated to reduction on chronic, non transmissible, diseases development. Generally, its consumption is less to the recommended and it is done principally as whole grain dishes. To increase the consumption, there is an especial interest in the use of new products. The main goal of this research was to design intermediate moisture bean purees (IMP) using soaked, cooked and grained Tortola bean, removing an important testa portion. In preparation of IMP two moisture levels, 25 and 30%, and two glycerol levels, 10 and 15%, were studied. Purees were preserved at ambient temperature (20 +/- 2 degrees C) for 30 days. Proximal analysis, phytate content and trypsin inhibitors were determined in the original non processed purees. IMPs were analyzed at preparation time and after 15 and 30 days of storage for moisture content, pH and water activity. Besides, microbiological analysis for total plate count on aerobic mesophile microorganisms, molds and yeast, total colifoms, fecal coliforms and Staphylococcus aureus, was carried out. Global quality and sensory acceptance was also determined. IMPs presented a(w) values between 0.800 and 0.844, a pH between 6.20 and 6.24 and the microbiological counting was negative or far below the accepted limits for more strict foods. IMPs presented good qualifications for global quality and were well accepted. Sensory parameters maintain their values during storage, except for color that in treatment with 30% moisture and 10% glycerol showed a light darkening. It is possible to elaborate intermediate moisture bean puree, with low level of antinutritional compounds, good quality and sensory acceptance and with adverse conditions for the development of food safety importance microorganisms.     

Structural changes during pitch-based carbon granular composites carbonisation

This article deals with the study of carbon composites behavior during their carbonization. Composites were prepared using four granular carbons (graphite, anthracite, green petroleum coke, and foundry coke) and four pitches (a commercial impregnating coal-tar pitch, an air-blown and two thermally treated pitches). The evolution of the optical microstructure, porosity, volume, and weight of carbon composites was monitored at different intermediate carbonization temperatures (350, 500, 700, and finally 1000 °C). The porosity of composites increases with carbonization due to volume changes and weight loss of pitches. Weight loss of carbon composites during their carbonization mainly depends on the pitch characteristics and it was slightly influenced by the presence of granular carbon. On the other hand, carbon composites with the commercial coal-tar pitch and foundry coke, anthracite, or graphite deform in the initial stages of carbonization (<350 °C) probably due to the lower porosity of the green pellets and the high amount of low-molecular weight compounds of the pitch. Carbon composites with green petroleum coke underwent important dimensional changes during their carbonization, expanding initially and then shrinking at temperatures above 700 °C. The type of granular carbon strongly influenced the microstructure of the final carbon composite, as a result of its effect on the development of mesophase. Graphite, anthracite and foundry coke delays mesophase development, whereas green petroleum coke accelerates mesophase formation.     

Hybrid organic–inorganic materials based on polypyrrole and 1,3-dithiole-2-thione-4,5-dithiolate (DMIT) containing dianions

The synthesis of hybrid materials by electropolymerization of pyrrole and inorganic complexes based on the DMIT ligand (1,3-dithiole-2-thione-4,5-dithiolate), e.g. [NEt₄]₂[M(DMIT) _n ] (M = Ni, Pd or Pd, n = 2; M = Sn, n = 3], in acetonitrile solution is reported. Spectroscopic data showed that DMIT-containing anions, [M(DMIT) _n ]²⁻, were inserted into the polypyrrole framework without chemical modification during the electropolymerization process. Cyclic voltammetry showed that materials obtained were electroactive, undergoing redox processes related to both the conducting polymer and the counteranions. The electrochemical results also suggest that, in the case of the transition metal containing films, the counteranions are not trapped in the PPy matrix but undergo anion exchange during the redox cycle of PPy. However, an opposite behaviour was observed with the film with [M(DMIT) _n ]²⁻. The films exhibit good thermal stabilities and have conductivity values expected for semiconductors. This study of these hybrid materials highlights the importance of targeting specific materials for specific applications.

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Representation of journals from five neighboring European countries in the Journal Citation Reports

This study explores the representation of scientific journals from Italy, Hungary, Slovenia, Croatia, and Serbia and Montenegro in the Thomson Scientific’s 2005 Journal Citation Reports (JCR). The number of journals covered by JCR was analyzed in relation to scientific productivity of selected countries and the size of their economies, and no apparent relationship between these factors was found. Our findings suggest that other factors, including the quality of individual journals, may influence how many journals a country will have in the JCR.     

Synergistic effects between κ-carrageenan and locust bean gum on physicochemical properties of edible films made thereof

The development of mixed systems, formed by locust bean gum (LBG), and κ-carrageenan (κ-car) can offer new interesting applications such as the development of edible films with particular properties. κ-car/LBG blend films with different ratios were developed, and their effects on films’ physical properties were assessed. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) patterns, dynamic mechanical analysis (DMA) and Fourier-transform infrared (FTIR) spectroscopy techniques were used to highlight the interactions between the two polysaccharides. The addition of κ-car to LBG improved the barrier properties of the films leading to a decrease of water vapor permeability (WVP). Improved values of elongation-at-break (EB) were registered when the ratio of κ-car/LBG was 80/20 or 40/60 (% w/w). Moreover, the κ-car/LBG blend films enhance the tensile strength (TS) compared to κ-car and LBG films. FTIR results suggested that hydrogen bonds interactions between κ-car and LBG have a great influence in films’ properties e.g. moisture content, WVP. Therefore, different κ-car/LBG ratios can be used to tailor edible films with enhanced barrier and mechanical properties.