Background/Aims: The finding that endogenous ouabain acts as a hormone prompted efforts to elucidate its physiological function. In previous studies, we have shown that 10 nM ouabain (i.e., a concentration within the physiological range) modulates cell-cell contacts such as tight junctions and apical/basolateral polarity. In this study, we examined whether 10 nM ouabain affects another important cell-cell feature: gap junction communication (GJC). Methods: We employed two different approaches: 1) analysis of the cell-to-cell diffusion of neurobiotin injected into a particular MDCK cell (epithelial cells from dog kidneys) in a confluent monolayer by counting the number of neighboring cells reached by the probe and 2) measurement of the electrical capacitance. Results: We found that 10 nM ouabain increase GJC by 475% within 1 hour. The Na+-K+-ATPase acts as a receptor of ouabain. In previous works we have shown that ouabain activates c-Src and ERK1/2 in 1 hour; in the present study we show that the inhibition of these proteins block the effect of ouabain on GJC. This increase in GJC does not require synthesis of new protein components, because the inhibitors cycloheximide and actinomycin D did not affect this phenomenon. Using silencing assays we also demonstrate that this ouabain-induced enhancement of GJC involves connexins 32 and 43. Conclusion: Ouabain 10 nM increases GJC in MDCK cells.

Auxetic metamaterials are known for having a negative Poisson's ratio (NPR) and for displaying the unexpected properties of lateral expansion when stretched and densification when compressed. Even though a wide set of micro-manufacturing resources have been used for the development of auxetic metamaterials and related devices, additional precision and an extension to other families of materials is needed for their industrial expansion. In addition, their manufacture using ceramic materials is still challenging. In this study we present a very promising approach for the development of auxetic metamaterials and devices based on the use of lithography-based ceramic manufacturing. The process stands out for its precision and complex three-dimensional geometries attainable, without the need of supporting structures, and for enabling the manufacture of ceramic auxetics with their geometry controlled from the design stage with micrometric precision. To our knowledge it represents the first example of application of this technology to the manufacture of auxetic geometries using ceramic materials. We have used a special three-dimensional auxetic design whose remarkable NPR has been previously highlighted.

In our work we present the complete development process of geometrically complex microvascular shape-memory polymer actuators. The complex geometries and three-dimensional networks are designed by means of computer aided design resources. Manufacture is accomplished, in a single step, by means of laser stereolithography, directly from the computeraided design files with the three dimensional geometries of the different actuators under development. To our knowledge, laser stereolithography is applied here for the first time to the development of shape memory polymer devices with complex geometries and inner microvasculatures for their activation using a thermal fluid. Final testing of the developed actuators helps to validate the approach and to put forward some present challenges.

The possibility of manufacturing textured materials and devices, with surface properties controlled from the design stage, instead of being the result of machining processes or chemical attacks, is a key factor for the incorporation of advanced functionalities to a wide set of micro-and nanosystems. High-precision additive manufacturing (AM) technologies based on photopolymerization, together with the use of fractal models linked to computer-aided design tools, allow for a precise definition of final surface properties. However, the polymeric master parts obtained with most commercial systems are usually inadequate for biomedical purposes and their limited strength and size prevents many potential applications. On the other hand, additive manufacturing technologies aimed at the production of final parts, normally based on layer-by-layer melting or sintering ceramic or metallic powders, do not always provide the required precision for obtaining controlled micro-structured surfaces with high-aspect-ratio details. Towards the desired degree of precision and performance, lithography-based ceramic manufacture is a remarkable option, as we discuss in the present study, which presents the development of two different micro-textured biodevices for cell culture. Results show a remarkable control of the surface topography of ceramic parts and the possibility of obtaining design-controlled micro-structured surfaces with high-aspect-ratio micro-metric details.

The possibilities for improving the control of greenhouse fogging systems, were studied by comparing several combinations of ventilation cooling techniques, shade screening and low-pressure fogging. The study was divided into three parts: experiments, modelling and simulations.In the first part of the paper, ten combinations of five cooling techniques were tested during the summers of 2002 and 2003 in a 132 m 2 greenhouse with a steel structure and a single-layer methacrylate cover located in Madrid, Spain. An analysis of variance of the climatic parameters was carried out to determine which combinations produced significant differences in inside temperature or relative humidity. Comparing the values for the inside to outside temperature difference, the combination of a shade screen and above-screen fogging achieved a difference in temperature almost the same as that for under-screen fogging, but the relative humidity was significantly lower.In the second part of the study a dynamic model was developed (2002) and validated (2003). The mean absolute error obtained for inside temperature was similar in the fit and the validation and it was less than 1.5 °C in both cases.The model was used to simulate the inside air temperature for a fog system working without shading, and above and under a shade screen. Control algorithms were developed for reducing system water consumption. In the three cases a simple on/off control with a fixed fogging cycle was compared with a pulse width modulation (PWM) strategy, in which the duration of the fogging pulse was increased as a function of inside temperature. The strategies with PWM applied to the fog system were able to reduce water consumption by 8-15% with respect to the strategies with a fixed fogging cycle.

SummaryThe continued expansion of additive manufacturing (AM) techniques, evolving from its initial role as a rapid prototyping method, toward effective resources for generating final products, is reshaping the production sector and its needs. The development of systematic methodologies for the generation of mechanically optimized support structures for AM processes is an important issue which impacts the eco-efficiency and quality of final parts. The shift from regular lattice support structures and complex support meshes, toward bioinspired support structures, using, for instance, tree-like and fractal geometries, may provide feasible solutions with optimal ratios between mechanical performance and quantity of material used. In a similar way as biomimetics has provided revolutionary solutions to fields including architecture, mechanical engineering, and civil engineering, it may well impact the field of solid freeform fabrication. The possibilities relate not just to aspects related to part geometries and final applications (as is already happening), but also in manufacturing challenges such as the problem of obtaining eco-efficient and reliable supports. In this article, we summarize a recently developed methodology, in the framework of the European Union (EU) "ToMax" Project, for the generation of bioinspired fractal or tree-like support structures and provide six application examples, starting with very simple geometries and generalizing the process for more complex parts. Eco-efficiency is assessed by a final comparative study using support structures generated with conventional software. Keywords:additive manufacturing (AM) bioinspired design computer-aided design (CAD) eco-efficiency industrial ecology support structures Supporting information is linked to this article on the JIE website

This study evaluated the application of recuperative thickening (RT) to enhance anaerobic digestion (AD) performance for AD systems with thermal hydrolysis pretreatment (THP). RT was applied for two different reasons: (a) for increasing the sludge retention time (SRT) to degrade slowly hydrolyzable materials more efficiently and (b) for maintaining SRT at decreased hydraulic retention time (HRT) thus showing potential for increased AD throughput rates. A SRT increase from 15 to 30 days by RT application did not improve AD performance or hydrolysis rates significantly as 15‐day SRT was already a factor 2 higher than the estimated washout SRT. When applying RT to increase throughput rates (HRT of 7 days) while maintaining 15‐day SRT, no negative impact on biogas production or hydrolysis kinetics was observed. It was estimated that RT application on THP digesters can increase digester throughput by 100% and thus show clear potential for further AD intensification. Practitioner points Increased SRT from 15 to 30 days through recuperative thickening application did not improve biogas production. A lower required minimum SRT (6–7 days) was estimated in THP‐AD systems compared to conventional AD. Operation at decreased HRT by RT application resulted in similar AD performance under constant organic loading rates. A 100% increase in throughput rates can be applied using RT without decreasing AD performance.

Appeals to public participation and, more generally, to a wider involvement of civic networks in the management of environmental conflicts are becoming more common after the difficulties that both the Market and the State appear to have in regulating these conflicts. The concern of this paper is with how central elements in civic society, such as interpersonal trust and community-building mechanisms, are influenced by environmental catastrophes. The case of the toxic spill disaster in Doñana, Spain, is presented in order to examine whether this accident had any effect on interpersonal trust and the mobilization of civic networks in the area. From the analysis, it can be concluded that involvement of civic networks in the management of these situations depends on the magnitude (real or perceived) of the disaster but also on the performance of public institutions regarding the event.