Imaging of the Cytoplasmic Leaflet of the Plasma Membrane by Atomic Force Microscopy

The cytoplasmic face of ventral cell membranes of Madin-Darby canine kidney (MDCK) cells grown on glass coverslips was imaged by atomic force microscopy (AFM) in air and under aqueous medium, in contact mode. Micrometer range scans on air-dried samples revealed a heterogeneous structure with some filaments, likely corresponding to actin filaments that abut the inner leaflet of the membrane, and a few semi-organized lattice structures that might correspond to clathrin lattices. Experiments in phosphate-buffered saline confirmed the heterogeneity of the inner membrane surface with the presence of large (\u3e 100 nm) globular structures emerging from the surface. Using sub-micrometer scan ranges, protruding particles, that occupy most of the membrane surface, were imaged in liquid medium and in air. These particles, 8 to 40 nm x-y size, were still present following ethanol dehydration which extracts a large fraction of membrane lipids, indicating their proteic nature. Due, at least partly, to the presence of some peripheral proteins, high magnification images of the inner membrane surface were heterogeneous with regard to particle distribution. These data compare with those previously reported for the external membrane leaflet at the surface of living MDCK cells. They show that details of the cytosolic membrane surface can be resolved by AFM. Finally, the images support the view of a plasma membrane organization where proteins come into close proximity

Mi-Learn : an evaluation of an m-learning management system

M-Learning is a novel concept concerned with delivering learning content over mobile devices, which today is being seen as a way to support for conventional and collaborative learning as well as for extending the scope of e-learning. This paper presents the work carried out on a research project named Mi-Learn, whose goal is that of gathering background knowledge within the field of m-learning, identification of related research problems, and creating an environment where solutions to these problems can be identified and evaluated. Pocket SCORM initiatives such as [ADL04] that are working towards a set of standards for m-learning have identified the restricted user interface and the requirement for offline learning sessions as the two major challenges in this area. The work presented in this paper forms part of the first phase of an m- learning research project and concentrates on the first of these challenges. By means of a pilot m-learning management system, an evaluation exercise was carried out in order to assess the impact of a restricted user interface on the learning experience. The evaluation carried out takes both the pedagogical and user interface aspects as the evaluation criteria. Evaluation results show that currently there seems to be a value for m-learning, but more as an extension for exiting e-learning programmes rather than a complete learning management system on its own. The results also helped in clarifying the research area and setting a direction for further research work.peer-reviewe

Mapping the Early Cortical Folding Process in the Preterm Newborn Brain

In the developing human brain, the cortical sulci formation is a complex process starting from 14 weeks of gestation onward. The potential influence of underlying mechanisms (genetic, epigenetic, mechanical or environmental) is still poorly understood, because reliable quantification in vivo of the early folding is lacking. In this study, we investigate the sulcal emergence noninvasively in 35 preterm newborns, by applying dedicated postprocessing tools to magnetic resonance images acquired shortly after birth over a developmental period critical for the human cortex maturation (26-36 weeks of age). Through the original three-dimensional reconstruction of the interface between developing cortex and white matter and correlation with volumetric measurements, we document early sulcation in vivo, and quantify changes with age, gender, and the presence of small white matter lesions. We observe a trend towards lower cortical surface, smaller cortex, and white matter volumes, but equivalent sulcation in females compared with males. By precisely mapping the sulci, we highlight interindividual variability in time appearance and interhemispherical asymmetries, with a larger right superior temporal sulcus than the left. Thus, such an approach, included in a longitudinal follow-up, may provide early indicators on the structural basis of cortical functional specialization and abnormalities induced by genetic and environmental factor

Primary cortical folding in the human newborn: an early marker of later functional development

In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain developmental and neuropsychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormalities might be present long before the appearance of functional symptoms. So far, the precise mechanisms responsible for such alteration in the convolution pattern during intra-uterine or post-natal development are still poorly understood. Here we compared anatomical and functional brain development in vivo among 45 premature newborns who experienced different intra-uterine environments: 22 normal singletons, 12 twins and 11 newborns with intrauterine growth restriction (IUGR). Using magnetic resonance imaging (MRI) and dedicated post-processing tools, we investigated early disturbances in cortical formation at birth, over the developmental period critical for the emergence of convolutions (26-36 weeks of gestational age), and defined early ‘endophenotypes' of sulcal development. We demonstrated that twins have a delayed but harmonious maturation, with reduced surface and sulcation index compared to singletons, whereas the gyrification of IUGR newborns is discordant to the normal developmental trajectory, with a more pronounced reduction of surface in relation to the sulcation index compared to normal newborns. Furthermore, we showed that these structural measurements of the brain at birth are predictors of infants' outcome at term equivalent age, for MRI-based cerebral volumes and neurobehavioural development evaluated with the assessment of preterm infant's behaviour (APIB

The SIGMA rat brain templates and atlases for multimodal MRI data analysis and visualization

Preclinical imaging studies offer a unique access to the rat brain, allowing investigations that go beyond what is possible in human studies. Unfortunately, these techniques still suffer from a lack of dedicated and standardized neuroimaging tools, namely brain templates and descriptive atlases. Here, we present two rat brain MRI templates and their associated gray matter, white matter and cerebrospinal fluid probability maps, generated from ex vivo [Formula: see text]-weighted images (90 µm isotropic resolution) and in vivo T2-weighted images (150 µm isotropic resolution). In association with these templates, we also provide both anatomical and functional 3D brain atlases, respectively derived from the merging of the Waxholm and Tohoku atlases, and analysis of resting-state functional MRI data. Finally, we propose a complete set of preclinical MRI reference resources, compatible with common neuroimaging software, for the investigation of rat brain structures and functions.This work is part of the SIGMA project with the reference FCT-ANR/NEU-OSD/0258/2012, co-financed by the French public funding agency ANR (Agence Nationale pour laRecherche, APP Blanc International II 2012), the Portuguese FCT (Fundação para aCiência e Tecnologia) and the Portuguese North Regional Operational Program (ON.2—O Novo Norte) under the National Strategic Reference Framework (QREN), through theEuropean Regional Development Fund (FEDER) as well as the Projecto Estratégico co-funded by FCT (PEst-C/SAU/LA0026-/2013) and the European Regional DevelopmentFund COMPETE (FCOMP-01-0124-FEDER-037298). D.A.B. and A.N. were funded bygrants from FCT-ANR/NEU-OSD/0258/2012. R.M. was supported by the FCT fellow-ship grant with the reference PDE/BDE/113604/2015 from the PhDiHES program. A.C.was supported by a grant from the foundation NRJ. P.M. was funded by FundaçãoCalouste Gulbenkian (Portugal;‘Better mental health during ageing based on temporalprediction of individual brain ageing trajectories TEMPO’) with Grant Number P-139977. France Life Imaging is acknowledged for its support in funding the NeuroSpinplatform of preclinical MRI scanners. The authors also acknowledge and thank EdwardGanz, MD, for proof reading our work

Roti jduru

Ġabra ta’ poeżiji u proża li tinkludi: Kwartini ta’ C. Cassar – Dak li ħalla l-ħares ta’ Pawlu Cachia – Epigrammi ta’ Peter A. Caruana – Lill-Madonna tal-arju ta’ Mario Agius – Il-fatati li ħatfu lil Ġomu “Xewka” ta’ Ġużè Dimech Debono – Bla mħabba ta’ Ġorġ Borg – Il-bieb ta’ l-infern ta’ P. Jos. Cremona – Roti jduru ta’ C. Cassar.peer-reviewe

Hawn jien, Ġesù...

Ġabra ta’ poeżiji u proża li tinkludi: Biex nagħarfu ngħixu ta’ G. Z. A. – Il-qalb ta’ John Sciberras – L-istedina ta’ Vic. Apap – Lill-bniedem ta’ Joseph C. Sciberras – Il-hena ta’ tfuliti ta’ George Stevens – L-ewwel ta’ Mejju ta’ Karmenu Ellul Galea – Epigrammi ta’ Pawlu Cachia – Ġibtlek bukkett ġilju ta’ Ġużè Galea – De profundis ta’ A. Agius Muscat – Did-dwejra bħal ħajja ta’ Ġużè Cardona – Ma’ dik li ġejja mill-bogħod ta’ Joe Mejlak – Hawn jien, Ġesù... ta’ Bro. Henry.peer-reviewe