Zeolite sensitized photoelectron transfer: Modulation of reduction potentials

The remarkable efficiency of conversion of light to chemical energy observed in green plant photosynthesis arises due to the spatial positioning of the sensitizers and the molecules involved in the electron relay. The architecture of zeolite cages also allows for positioning of molecules spatially, and in a primitive sense mimics photosynthesis. Using entrapped RU(bpy)₃²⁺ as sensitizer, directional electron transfer to propylviologen sulfonate (PVS) in solution is possible if the mediating viologen in the zeolite has the appropriate reduction potential e.g. N,N'-tetramethylene-2,2' bipyridinium (DQ²⁺). The reduction potentials of viologens is controlled by introducing steric effects in the molecule such that planarity of the two bipyridyl rings upon one-electron reduction is difficult to achieve. We show that by using viologen molecules that span several supercages of a zeolite e.g. benzylviologen (BV²⁺), we can also alter the reduction potential, but because of the steric constraints imposed by the zeolite framework. Thus, in this example, not only does the zeolite provide spatial orientation, but also modulates the reduction potential of the encapsulated viologen.     

Dissolved metal background levels in marine waters, for the assessment of the physico-chemical status, within the European Water Framework Directive

The European Water Framework Directive (WFD) has, as its ultimate aim, a reduction in the concentrations of hazardous substances in the marine environment, i.e. 'background' values. Hence, the determination of natural background levels of heavy metals, to distinguish between natural element concentrations and anthropogenically-influenced concentrations, is highly relevant. Some studies have shown the convenience in the derivation of local background levels, especially if they are necessary for environmental assessment. Nevertheless, although such studies exist for sediments, there are only a few previous investigations on metal background values in sea water. Likewise, there is not any standard procedure to determine such levels in waters, nor general agreement on the statistical methodologies to be applied. In this contribution, background levels of heavy metals (As, Cu, Mn, Ni, Pb and Zn), in estuarine and coastal waters within the Basque Country (northern Spain), according to ranges in salinity, are estimated using statistical tools. Ni and Pb have been considered elsewhere (2455/2001/EC) as priority substances under the WFD. Hence, this approach can assist further in the determination of water reference conditions, to assess chemical and physico-chemical status in other European countries; this, affects, ultimately, the ecological status, as defined within the WFD.     

Where does the money go? Economic flow analysis of construction projects

A new approach is introduced for analysing the economic flows in a construction project that will complement the existing methods. The main focus of the new method is to trace the flow of costs in the project and identify their spatial characteristics as well as who are the final recipients. This type of analysis highlights the flow of costs of the specific project in the local economy. It can be used for decision-making purposes from the project-commissioning party. Costs were divided into six categories, namely: labour, materials, energy, office overheads, taxes and personnel, and into two levels: local and national. Three case studies of stone and reinforced concrete structures were selected and analysed to test the application of this method. The case studies showed that this method and the representation by a Sankey diagram can provide useful insights regarding both the spatialized distribution of the cost of a project and the economic flows going to direct labour versus overhead and taxes. For future projects, local authorities or developers can select the most economically suitable strategy maximizing the income of the local community.     

Insight into fundamental aspects of the EDM process using multidischarge numerical simulation

The electrical discharge machining (EDM) process is a popular non-traditional machining process, but, although it is widely used in industry, there is still a lack of scientific knowledge about its fundamentals. This paper discusses some aspects of the discharge process at the sight of the results obtained with a previously developed thermal model, which is capable of simulating the superposition of successive discharges which leads to the formation of the ??EDMed?? surface. Some process characteristics such as the percentage of discharge energy transferred to the workpiece, plasma channel growth, material removal mechanism, and the influence of convective cooling are discussed in this paper, based on the information provided by the adjustments of two different EDM regimes (corresponding to roughing and finishing operations). Predictions of the extension of the recast layer and the heat-affected layer for both regimes are also addressed, and their comparison with experimental measurements shows a good agreement, which confirms the validity of the modeling tool.     

Enhanced light extraction in ITO-free OLEDs using double-sided printed electrodes

We show how nanoimprint lithographic techniques are particularly suited for the realization of OLED device structures. We tested them to realize nanopatterned metallic electrodes containing photonic crystals to couple the light out and plasmonic crystals showing extraordinary transmission. At similar current densities, a two-fold electroluminescence is achieved with devices having double-sided structured metallic electrodes as compared to a control OLED with an ITO anode. The use of combined nanoimprint lithography processes has the potential to expand the performance range of various organic optoelectronic devices.     

Poly[ethylene‐co‐(acrylic acid)]‐based nanocomposites: Thermal and mechanical properties and their structural characteristics studied by Raman spectroscopy

Nanocomposites containing carbon nanotubes (CNTs) as nanofillers and poly[ethylene‐co‐(acrylic acid)] (PEAA) or a polymer miscible mixture of PEAA and poly(2‐ethyl‐2‐oxazoline) (PEOx) as a matrix were prepared by the solution‐evaporation method with minimal damage to nanotubes. CNTs were prepared by chemical vapor deposition (CVD) with ethanol as the source of carbon. Raman spectroscopy confirmed the presence of single walled carbon nanotubes (SWNTs). High resolution transmission electron microscopy (HRTEM) showed the formation of multi walled carbon nanotubes (MWNTs). Thermal and mechanical properties of the nanocomposites were studied by analyzing samples containing different amounts of CNTs. The degree of crystallinity (X_c) of the PEAA‐based nanocomposite containing a smaller amount of CNTs was larger (X_c = 17.0%) than both the one of pure PEAA (X_c = 14.6 %) and PEAA‐based nanocomposite containing higher amounts of CNTs (X_c = 15.0%). The Young's modulus, ultimate stress, deformation at break, and toughness obtained from unidirectional tensile tests of the CNTs (1 wt%)‐PEAA nanocomposite were higher than both the one of pure PEAA and CNTs (5 wt%)‐PEAA nanocomposite. When a polymer mixture of PEAA/PEOx (containing 80 wt% of PEAA) was used as a matrix, a better mechanical response was also detected for nanocomposite containing 1 wt% CNTs. The nanocomposites containing small amounts of CNTs prepared here have potential to be used as coatings of metal or glass surfaces expecting a better mechanical performance than the one of pure matrix. POLYM. COMPOS., © 2011 Society of Plastics Engineers.     

Analysis of Molecular Networks in the Cerebellum in Chronic Schizophrenia: Modulation by Early Postnatal Life Stressors in Murine Models

Despite the growing importance of the cerebellum as a region highly vulnerable to accumulating molecular errors in schizophrenia, limited information is available regarding altered molecular networks with potential therapeutic targets. To identify altered networks, we conducted one-shot liquid chromatography–tandem mass spectrometry in postmortem cerebellar cortex in schizophrenia and healthy individuals followed by bioinformatic analysis (PXD024937 identifier in ProteomeXchange repository). A total of 108 up-regulated proteins were enriched in stress-related proteins, half of which were also enriched in axonal cytoskeletal organization and vesicle-mediated transport. A total of 142 down-regulated proteins showed an enrichment in proteins involved in mitochondrial disease, most of which were also enriched in energy-related biological functions. Network analysis identified a mixed module of mainly axonal-related pathways for up-regulated proteins with a high number of interactions for stress-related proteins. Energy metabolism and neutrophil degranulation modules were found for down-regulated proteins. Further, two double-hit postnatal stress murine models based on maternal deprivation combined with social isolation or chronic restraint stress were used to investigate the most robust candidates of generated networks. CLASP1 from the axonal module in the model of maternal deprivation was combined with social isolation, while YWHAZ was not altered in either model. METTL7A from the degranulation pathway was reduced in both models and was identified as altered also in previous gene expression studies, while NDUFB9 from the energy network was reduced only in the model of maternal deprivation combined with social isolation. This work provides altered stress- and mitochondrial disease-related proteins involved in energy, immune and axonal networks in the cerebellum in schizophrenia as possible novel targets for therapeutic interventions and suggests that METTL7A is a possible relevant altered stress-related protein in this context.     

CCL2 Inhibition of Pro-Resolving Mediators Potentiates Neuroinflammation in Astrocytes

The chemokine CCL2 participates in multiple neuroinflammatory processes, mainly through the recruitment of glial cells. However, CCL2 has also been proven to exert different types of actions on these cells, including the modification of their response to inflammatory stimuli. In the present study we analyzed the effect of CCL2 on the resolution of inflammation in astrocytes. We observed that genetic removal of CCL2 increases the expression of the enzymes responsible for the synthesis of specialized pro-resolving mediators arachidonate 15-lipoxygenase and arachidonate 5-lipoxygenase in the brain cortex of 5xFAD mice. The expression of FPR2 receptor, known to mediate the activity of pro-resolving mediators was also increased in mice lacking CCL2.The downregulation of these proteins by CCL2 was also observed in cultured astrocytes. This suggests that CCL2 inhibition of the resolution of inflammation could facilitate the progression of neuroinflammatory processes. The production of the pro-inflammatory cytokine IL-1beta by astrocytes was analyzed, and allowed us to confirm that CCL2 potentiates the activation of astrocytes trough the inhibition of pro-resolving pathways mediated by Resolvin D1. In addition, the analysis of the expression of TNFalpha, MIP1alpha and NOS2 further confirmed CCL2 inhibition of inflammation resolution in astrocytes.     

First results on the combination of laser scanner and drilling resistance tests for the assessment of the geometrical condition of irregular cross-sections of timber beams

Old timber structures often present damaged elements with irregular cross-sections, hidden surfaces and even with loss of material due to decay. Within that scope, in this paper, a new methodology based on the combination of laser scanner and drilling resistance tests is proposed and developed with the aim of analyzing the apparent and resistant sections of timber beams with hidden surfaces and irregular cross-section affected by decay. The proposed methodology was initially calibrated with tests made on a timber beam within a laboratory environment and, then, its feasibility was tested on a case study regarding the timber roof of the Guimarães Castle keep. The results confirm the suitability of this methodology for assessment of the present geometrical properties of timber elements with an average error of 1.5 and 4.5%, respectively, in the calculation of the apparent section area and inertia.