The spark of life:The role of electric fields in regulating cell behaviour using the eye as a model system

Endogenous electric fields (EF) have long been known to influence cell behaviour during development, neural cell tropism, wound healing and cell behaviour generally. The effect is based on short circuiting of electrical potential differences across cell and tissue boundaries generated by ionic segregation. Recent in vitro and in vivo studies have shown that EF regulate not only cell movement but orientation of cells during mitosis, an effect which may underlie shaping of tissues and organs. The molecular basis of this effect is founded on receptor-mediated cell signalling events and alterations in cytoskeletal function as revealed in studies of gene deficient cells. Remarkably, not all cells respond directionally to EF in the same way and this has consequences, for instance, for lens development and vascular remodelling. The physical basis of EF effect may be related to changes induced in 'bound water' at the cell surface, whose organisation in association with trans-membrane proteins (e.g. receptors) is disrupted when EF are generated. Copyright © 2007 S. Karger AG.

An Ethical Production of Place:A Case for Economy in Architectural Design

Architects typically interpret Heidegger to mean that dwelling in the Black Forest, was more authentic than living in an industrialised society however we cannot turn back the clock so we are confronted with the reality of modernisation. Since the Second World War production has shifted from material to immaterial assets. Increasingly place is believed to offer resistance to this fluidity, but this belief can conversely be viewed as expressing a sublimated anxiety about our role in the world – the need to create buildings that are self-consciously contextual suggests that we may no longer be rooted in material places, but in immaterial relations.
This issue has been pondered by David Harvey in his paper From Place to Space and Back Again where he argues that the role of place in legitimising identity is ultimately a political process, as the interpretation of its meaning is dependent on whose interpretation it is. Doreen Massey has found that different classes of people are more or less mobile and that mobility is related to class and education rather than to nationality or geography. These thinkers point to a different set of questions than the usual space/place divide – how can we begin to address the economic mediation of spatial production to develop an ethical production of place? Part of the answer is provided by the French architectural practice Lacaton Vassal in their book Plus. They ask themselves how to produce more space for the same cost so that people can enjoy a better quality of life. Another French practitioner, Patrick Bouchain, has argued that architect’s fees should be inversely proportional to the amount of material resources that they consume. These approaches use economics as a starting point for generating architectural form and point to more ethical possibilities for architectural practice

A proposed method for evaluating the artisanal production of recycled plastic paving blocks in West Africa

Plastic wastes, and particularly plastic bags and sachets, are a major concern for urban and rural environment in African countries. In the last years some actions have been started for the plastic recycling like the artisanal production of paving blocks with melted plastic bags and sand, albeit with differences in production processes. Nevertheless, the environmental and economic impact of such activities is still to be confirmed. The aim of this study is to propose a methodology for assessing and comparing the environmental and energetic performances of artisanal methods, and for defining the overall quality of the produced blocks. This methodology has been shaped through the analysis of
production processes operated by artisans/small enterprises in West Africa and through physic-mechanical tests on the blocks. A questionnaire which allows an insight into the process and on the product has been developed and tested over five processes. Results show that a high input energy level is observed through all the processes, while considerable savings of energy could be achieved. Moreover, tests results confirmed the importance of the utilised plastic concerning thermal dilatation, mechanical resistance at higher temperature and cooling-shrinkage effects. In conclusion, doubts remain about the technical and environmental effectiveness of the sampled experiences, durability of the products and sustainability of this approach. Nevertheless, being the collection and recycling of plastic wastes a potential income generation activity for marginalised social groups in urban environment, a process optimisation could improve the impact of blocks production. Alternative recycling activities should also be considered.

Coal Combustion Residuals valorisation through the production of compressed masonry brick

The Niger Coal Society (Societé Nigérienne de Charbon – SONICHAR) produces electricity for local consumption in Tefereyre, 75 km north-west from Agadez, Niger. The coal combustion residuals production is about 150,000 tons per year. In order to reduce this environmental burden and to valorize these by-products, a study focusing on their physical and chemical features as well as on the mechanical resistance of compressed brick has been undertaken. Physical characterization of coal slag, chemical and lixiviation tests have been carried out, assessing the material main parameters, verifying the presence of hazardous composites and elements and comparing the obtained results with the findings of an in-deep literary review. Cement powder has been chosen as stabilizing agent as a preliminary option. Four different dosages have been tested and bricks have been produced with a hand-operated press. Compressive strength has been tested at different days of curing. Results show remarkable uniaxial compressive strengths (UCS) for all the mixes after cure, ranging from 4MPa up to more than 20MPa for the highest stabilization ratio. UCS higher than 5MPa have been observed for 20% and 30% cement stabilization ratios after only 7 days of cure, reaching respectively about 11MPa and 13MPa after 45 days. In conclusion obtained bricks show good mechanical resistance and low weight. No health threat has been detected from the obtained sample. Study developments are oriented towards the feasibility of the utilization of low-cost, locally available stabilization means, notably clay and cohesive soils, and on thermal properties assessment.

Production of a broad specificity antibody for the development and validation of an optical SPR screening method for free and intracellular microcystins and nodularin in cyanobacteria cultures

A highly sensitive broad specificity monoclonal antibody was produced and characterised for microcystin detection through the development of a rapid surface plasmon resonance (SPR) optical biosensor based immunoassay. The antibody displayed the following cross-reactivity: MC-LR 100%; MC-RR 108%; MC-YR 68%; MC-LA 69%; MC-LW 71%; MC-LF 68%; and Nodularin 94%. Microcystin-LR was covalently attached to a CM5 chip and with the monoclonal antibody was employed in a competitive 4min injection assay to detect total microcystins in water samples below the WHO recommended limit (1µg/L). A 'total microcystin' level was determined by measuring free and intracellular concentrations in cyanobacterial culture samples as this toxin is an endotoxin. Glass bead beating was used to lyse the cells as a rapid extraction procedure. This method was validated according to European Commission Decision 96/23/EC criteria. The method was proven to measure intracellular microcystin levels, the main source of the toxin, which often goes undetected by other analytical procedures and is advantageous in that it can be used for the monitoring of blooms to provide an early warning of toxicity. It was shown to be repeatable and reproducible, with recoveries from spiked samples ranging from 74 to 123%, and had % CVs below 10% for intra-assay analysis and 15% for inter-assay analysis. The detection capability of the assay was calculated as 0.5ng/mL for extracellular toxins and 0.05ng/mL for intracellular microcystins. A comparison of the SPR method with LC-MS/MS was achieved by testing six Microcystis aeruginosa cultures and this study yielded a correlation R(2) value of 0.9989.

Taguchi optimisation approach for production of activated carbon from phosphoric acid impregnated palm kernel shell by microwave heating

Taguchi method was applied to investigate the optimal operating conditions in the preparation of activated carbon using palm kernel shell with quadruple control factors: irradiation time, microwave power, concentration of phosphoric acid as impregnation substance and impregnation ratio between acid and palm kernel shell. The best combination of the control factors as obtained by applying Taguchi method was microwave power of 800 W, irradiation time of 17 min, impregnation ratio of 2, and acid concentration of 85%. The noise factor (particle size of raw material) was considered in a separate outer array, which had no effect on the quality of the activated carbon as confirmed by t-test. Activated carbon prepared at optimum combination of control factors had high BET surface area of 1,473.55 m² g-1 and high porosity. The adsorption equilibrium and kinetic data can satisfactorily be described by the Langmuir isotherm and a pseudo-second-order kinetic model, respectively. The maximum adsorbing capacity suggested by the Langmuir model was 1000 mg g-1.

Production of porous aluminium and iron sulphated oxyhydroxides using industrial grade coagulants for optimised arsenic removal from groundwater

The optimisation of Fe and Al oxyhydroxide materials produced using industrial grade coagulants is presented in this work. The effects of synthesis pH and post-synthesis washing procedure onto the arsenic adsorption capacity of the materials were investigated. It was shown that the materials produced at higher pH were more efficient in removing As(V), especially after cleaning procedure. The materials produced at lower pH were less efficient in removing As(V) but the higher presence of sulphate groups in the materials produced at lower pH enhanced As(III) adsorption. Most performing materials can remove up to 84.7 mg As(V) g^-1 or 77.9 mg As(III) g^-1.

On the scaling behavior of electric conductivity in [C(4)mim][NTf2]

In this work we examine, for the first time, the molar conductivity behavior of the deeply supercooled room temperature ionic liquid [C₄mim][NTf₂] in the temperature, pressure and volume thermodynamic space in terms of density scaling (TV^γ)⁻¹ combined with the equation of state (EOS). The exponent γ_σ determined from the Avramov model analysis is compared with the coefficient obtained from the viscosity studies carried out at moderate temperatures. Therefore, the experimental results presented herein provide the answer to the long-standing question regarding the validity of thermodynamic scaling of ionic liquids over a wide temperature range, i.e. from the normal liquid state to the glass transition point. Finally, we investigate the relationship between the dynamic and thermodynamic properties of [C₄mim][NTf₂] represented by scaling exponent γ and Grüneisen constant γ_G, respectively.

Rapid and efficient production of L-lactate from xylose using electrodialysis culture-associated product separation

L-Lactate was produced from xylose using electrodialysis culture (ED-C)-associated product separation. In a medium containing 50 g xylose/l, the ED-C was completed in only 32 h (i.e. less than half the time taken by the control culture, without electrodialysis). At 80 g xylose/l, the control culture was unable to consume more than 50 g xylose/1, whereas the ED-C showed increased xylose consumption and was completed by 45 h. The maximum rate of lactate production in the ED-C was higher than that in the control culture. ED-C was also carried out (at 80 g initial xylose/ l) with a supply of fresh xylose-free medium. This ED-C was completed within 30 h, which represents a reduction in fermentation time of 15 h when compared to ED-C without addition of xylose-free medium. Thus, rapid production of L-lactate was achieved by using ED-C which supplied fresh xylose-free medium.

Understanding the 'production' of the schooling identities of young working class boys: time to move beyond the sociological/psychological divide?

In recent times the sociology of childhood has played an important role in challenging the dominance of Piagetian models of child development in shaping the way we think about children and childhood. What such work has successfully achieved is to increase our understanding of the socially constructed nature of childhood; the social competence and agency of children; and the diverse nature of children’s lives, reflecting the very different social contexts within which they are located. One of the problems that has tended to be associated with this work, however, is that in its critique of developmentalism it has tended simply to replace one orthodoxy (psychology) with another (sociology) rather than providing the opportunity to transcend this divide. The purpose of this paper is to demonstrate some of the potential ways in which the sociological/psychological divide might be transcended and the benefits of this for understanding, more fully, the ‘production’ of children’s schooling identities. In particular it shows how some of the key sociological insights to be found in the work of Bourdieu may be usefully extended by the work inspired by the developmental psychologist, Vygotsky. The key arguments are illustrated by reference to ethnographic data relating to the schooling experiences and identities of a group of 5-6 year old working class boys.

Impact of electric vehicles on a carbon constrained power system—a post 2020 case study

Electric vehicles (EVs) offer great potential to move from fossil fuel dependency in transport once some of the technical barriers related to battery reliability and grid integration are resolved. The European Union has set a target to achieve a 10% reduction in greenhouse gas emissions by 2020 relative to 2005 levels. This target is binding in all the European Union member states. If electric vehicle issues are overcome then the challenge is to use as much renewable energy as possible to achieve this target. In this paper, the impacts of electric vehicle charged in the all-Ireland single wholesale electricity market after the 2020 deadline passes is investigated using a power system dispatch model. For the purpose of this work it is assumed that a 10% electric vehicle target in the Republic of Ireland is not achieved, but instead 8% is reached by 2025 considering the slow market uptake of electric vehicles. Our experimental study shows that the increasing penetration of EVs could contribute to approach the target of the EU and Ireland government on emissions reduction, regardless of different charging scenarios. Furthermore, among various charging scenarios, the off-peak charging is the best approach, contributing 2.07% to the target of 10% reduction of Greenhouse gas emissions by 2025.