Applications of nanotechnology to the central nervous system

Nanotechnology and nanomaterials, in general, have become prominent areas of academic research. The ability to engineer at the nano scale is critical to the advancement of the physical and medical sciences. In the realm of physical sciences, the applications are clear: smaller circuitry, more powerful computers, higher resolution instruments. However, the potential impact in the fields of biology and medicine are perhaps even grander. The implementation of novel nanodevices is of paramount importance to the advancement of drug delivery, molecular detection, and cellular manipulation. The work presented in this thesis focuses on the development of nanotechnology for applications in neuroscience. The nervous system provides unique challenges and opportunities for nanoscale research. This thesis discusses some background in nanotechnological applications to the central nervous system and details : (1) The development of a novel calcium nanosenser for use in neurons and astrocytes. We implemented the calcium responsive component of Dr. Roger Tsien's Cameleon sensor, a calmodulin-M13 fusion, in the first quantum dot-based calcium sensor. (2) The exploration of cell-penetrating peptides as a delivery mechanism for nanoparticles to cells of the nervous system. We investigated the application of polyarginine sequences to rat primary cortical astrocytes in order to assess their efficacy in a terminally differentiated neural cell line. (3) The development of a cheap, biocompatible alternative to quantum dots for nanosensor and imaging applications. We utilized a positively charged co-matrix to promote the encapsulation of free sulforhodamine B in silica nanoparticles, a departure from conventional reactive dye coupling to silica matrices. While other methods have been invoked to trap dye not directly coupled to silica, they rely on positively charged dyes that typically have a low quantum yield and are not extensively tested biologically, or they implement reactive dyes bound to larger encapsulated molecule

Complete in situ stress determination in an argillite sedimentary formation

International audienceAndra has conducted a very comprehensive investigation on the in situ stress field within an argillite formation interbeded between two stiffer limestone formations, for the development of its underground research laboratory. A series of hydraulic tests has been conducted in boreholes located in the vicinity of the future site. Borehole and shaft convergence measurements were also carried out to analyse the mechanical behaviour of the rock. Throughout the stress measurement campaign, several borehole images have shown breakouts or induced fractures, that have been analysed in terms of in situ stress field, both in the argillite and in the limestone layers. All these reliable data highlight the high dependency of the state of stress on the rheology of the formation. A high ratio between the two horizontal principal stress components – ranging from 1.3 to 2.0 – has been observed in the limestones, whereas the maximum horizontal principal stress component has been found to be close to the lithostatic stress in the clay formation at the main level of the laboratory; i.e. at the 490 m depth

Geophysics applied to nuclear waste disposal investigations in Switzerland

T. Spillmann, P. Blümling, E. Manukyan, S. Marelli, H. R. Maurer, S.A. Greenhalgh and A.G. Greenhttp://www.earthdoc.org/detail.php?pubid=4074