Neuronal growth on high-aspect-ratio diamond nanopillar arrays for biosensing applications

Monitoring neuronal activity with simultaneously high spatial and temporal resolution in living cell cultures is crucial to advance understanding of the development and functioning of our brain, and to gain further insights in the origin of brain disorders. While it has been demonstrated that the quantum sensing capabilities of nitrogen-vacancy (NV) centers in diamond allow real time detection of action potentials from large neurons in marine invertebrates, quantum monitoring of mammalian neurons (presenting much smaller dimensions and thus producing much lower signal and requiring higher spatial resolution) has hitherto remained elusive. In this context, diamond nanostructuring can offer the opportunity to boost the diamond platform sensitivity to the required level. However, a comprehensive analysis of the impact of a nanostructured diamond surface on the neuronal viability and growth was lacking. Here, we pattern a single crystal diamond surface with large-scale nanopillar arrays and we successfully demonstrate growth of a network of living and functional primary mouse hippocampal neurons on it. Our study on geometrical parameters reveals preferential growth along the nanopillar grid axes with excellent physical contact between cell membrane and nanopillar apex. Our results suggest that neuron growth can be tailored on diamond nanopillars to realize a nanophotonic quantum sensing platform for wide-field and label-free neuronal activity recording with sub-cellular resolution

Hydrogen production by chemical-looping reforming in a circulating fluidized bed reactor using Ni-based oxygen carriers

7 pages, 11 figures,.- Available online November 18, 2008.This work presents the experimental results obtained during auto-thermal chemical-looping reforming (CLR) in a 900 Wth circulating fluidized bed reactor under continuous operation using methane as fuel. Two oxygen carriers based on NiO and supported on γ-Al2O3 and α-Al2O3 were used during more than 50 h of operation with each oxygen carrier. During operation the effect of different operating variables, like fuel reactor temperature, H2O/CH4 molar ratio and solid circulation rate, on CH4 conversion and gas product distribution was analyzed. It was found that in all operating conditions CH4 conversion was very high (>98%) and the most important variable affecting to the gas product distribution was the solid circulation rate, that is, NiO/CH4 molar ratio. Similar gas product distribution was obtained working with both oxygen carriers although at different NiO/CH4 molar ratios. The oxygen carrier of NiO on α-Al2O3 needed lower NiO/CH4 molar ratio to reach the same gas product composition than the oxygen carrier of NiO on γ-Al2O3. Working at optimal operating conditions, 2.5 moles of H2 per mol of CH4 could be obtained in this process. During operation the oxygen carrier particles maintained their physical and chemical properties. These results suggest that these oxygen carriers could have a high durability, being suitable oxygen carriers for a CLR system. © 2008 Elsevier B.V. All rights reserved.This work was partially supported by the European Commission, under the 6th Framework Programme (CACHET Project, Contract no. 019972), and from the CCP2 (CO2 Capture Project), a partnership of BP, Chevron, Conoco-Phillips, Eni Technology, Norsk Hydro, Shell, Suncor, and Petrobras. M. Ortiz thanks Diputación General de Aragon for the F.P.I. fellowship.Peer Reviewe

International Student Mobility: An Identity Development Task?

Based on the review of literature on internationalization of education and on identity formation pro cesses in young adults, this cross - sectional study aims to investigate to which extent self - perceived dimensions of identity are associated to the main moti vations to study abroad. The participants in this study were 429 international university students of different nationalities. Findings revealed that the motivation to study abroa d for personal growth is strongly associated to the commitment and in - depth e xploration identity processes, whereas the motivation to study abroad with the aim of changing life style and enlarging job opportunities is positively associated with reconsideration of commitment and in - depth exploration. Furthermore, identity achieved s tudents showed the highest motivation to s tudy abroad for personal growth, while the motivation to study abroad to positively change life - styles and work conditions is strongly associated with the positive facet of identity crisis, which is otherwise calle d searching - moratorium status. Based on these results, the present survey provides useful questions and hypothesis for future researc

The Nintendo® Wii Fit Balance Board can be used as a portable and low-cost posturography system with good agreement compared to established systems

Background!#!Almost all epidemiological studies over the past 40 years have determined that the incidence of fragility fractures is increasing. Therefore, the assessment of postural stability and monitoring any progress during balance training for geriatric patients to prevent falls are becoming more important. The Nintendo!##!Methods!#!This prospective study analyzed the diagnostic value of the Wii Fit Balance Board in 41 healthy subjects using two measurements: the yoga task 'tree,' which is performed in one-leg stance; and the balance game 'table tilt.' Our investigation compared these tasks to two established, regularly used systems, the MFT-S3 Check and the Posturomed, by looking for correlation and agreement, using Bland-Altman plots, as well as for differences to demographic data. All measurement tools were also compared to the Sensory Organization Test-the gold standard for detecting impaired balance.!##!Results!#!We found a moderate correlation between the yoga exercise 'tree' and the Sensory Organization Test (correlation coefficient r = 0.514, p = 0.001) as well as the MFT-S3 Check (r = 0.356-0.472, p = 0.002-0.022) and the Posturomed (r = 0.345, p = 0.027). However, results from the balance game 'table tilt' did not show a significant correlation with those of the systems to which we compared it (p = 0.301-0.953).!##!Conclusions!#!According to the literature, the raw data from the Wii Fit Balance Board are comparable to that obtained by laboratory-grade force platforms. We have found, however, that the yoga pose 'tree,' as integrated into the Nintendo!##!Level of evidence!#!2b