Neurite outgrowth by the alternatively spliced region of human tenascin-C is mediated by neuronal alpha7beta1 integrin

The region of tenascin-C containing only alternately spliced fibronectin type-III repeat D (fnD) increases neurite outgrowth by itself and also as part of tenascin-C. We previously localized the active site within fnD to an eight amino acid sequence unique to tenascin-C, VFDNFVLK, and showed that the amino acids FD and FV are required for activity. The purpose of this study was to identify the neuronal receptor that interacts with VFDNFVLK and to investigate the hypothesis that FD and FV are important for receptor binding. Function-blocking antibodies against both alpha7 and beta1 integrin subunits were found to abolish VFDNFVLK-mediated process extension from cerebellar granule neurons. VFDNFVLK but not its mutant, VSPNGSLK, induced clustering of neuronal beta1 integrin immunoreactivity. This strongly implicates FD and FV as important structural elements for receptor activation. Moreover, biochemical experiments revealed an association of the alpha7beta1 integrin with tenascin-C peptides containing the VFDNFVLK sequence but not with peptides with alterations in FD and/or FV. These findings are the first to provide evidence that the alpha7beta1 integrin mediates a response to tenascin-C and the first to demonstrate a functional role for the alpha7beta1 integrin receptor in CNS neurons.

A study of the micro-mechanics of granular media

The development of more realistic constitutive models for granular media, such as sand, requires ingredients which take into account the internal micro-mechanical response to deformation. Unfortunately, at present, very little is known about these mechanisms and therefore it is instructive to find out more about the internal nature of granular samples by conducting suitable tests. In contrast to physical testing the method of investigation used in this study employs the Distinct Element Method. This is a computer based, iterative, time-dependent technique that allows the deformation of granular assemblies to be numerically simulated. By making assumptions regarding contact stiffnesses each individual contact force can be measured and by resolution particle centroid forces can be calculated. Then by dividing particle forces by their respective mass, particle centroid velocities and displacements are obtained by numerical integration. The Distinct Element Method is incorporated into a computer program 'Ball'. This program is effectively a numerical apparatus which forms a logical housing for this method and allows data input and output, and also provides testing control. By using this numerical apparatus tests have been carried out on disc assemblies and many new interesting observations regarding the micromechanical behaviour are revealed. In order to relate the observed microscopic mechanisms of deformation to the flow of the granular system two separate approaches have been used. Firstly a constitutive model has been developed which describes the yield function, flow rule and translation rule for regular assemblies of spheres and discs when subjected to coaxial deformation. Secondly statistical analyses have been carried out using data which was extracted from the simulation tests. These analyses define and quantify granular structure and then show how the force and velocity distributions use the structure to produce the corresponding stress and strain-rate tensors.

Femtosecond laser micro-inscription of optical coherence tomography resolution test artifacts

Optical coherence tomography (OCT) systems are becoming more commonly used in biomedical imaging and, to enable continued uptake, a reliable method of characterizing their performance and validating their operation is required. This paper outlines the use of femtosecond laser subsurface micro-inscription techniques to fabricate an OCT test artifact for validating the resolution performance of a commercial OCT system. The key advantage of this approach is that by utilizing the nonlinear absorption a three dimensional grid of highly localized point and line defects can be written in clear fused silica substrates.

Micro-fabrication of advanced photonic devices by means of direct point-by-point femtosecond inscription in silica

We present recent results on experimental micro-fabrication and numerical modeling of advanced photonic devices by means of direct writing by femtosecond laser. Transverse inscription geometry was routinely used to inscribe and modify photonic devices based on waveguiding structures. Typically, standard commercially available fibers were used as a template with a pre-fabricated waveguide. Using a direct, point-by-point inscription by infrared femtosecond laser, a range of fiber-based photonic devices was fabricated including Fiber Bragg Gratings (FBG) and Long Period Gratings (LPG). Waveguides with a core of a couple of microns, periodic structures, and couplers have been also fabricated in planar geometry using the same method.

Agents for change and changed agents:the micro-politics of change and feminism in the academy

This article explores gender politics and processes in the academy and investigates change from the perspectives of feminist academics. In particular, it explores the experiences of women academics attempting to effect change to the gendered status quo of their own institutions. Focusing on micro-politics, the feminist movement is empirically explored in localized spaces of resistance and in the small but significant individual efforts at making changes in academic institutions. The analysis is based on interviews with female academics working in business and management schools and focuses on the challenges for change and how change attempts affect their personal and professional identities. The article explores the range of change strategies that participants use as they try to progress in their academic career while staying true to their feminist values and priorities through both resisting and incorporating dominant discourses of academic work. The analysis highlights such tensions and focuses on a contextualized, bottom-up perspective on change that, unlike more totalizing theorization, takes into account mundane and lived experiences at the level of the individual. © 2012 Blackwell Publishing Ltd.

Nurturing communities of practice for effective university-to-industry technology transfer:two exemplar cases from the Cauca Region of Columbia

This paper’s primary aim is to demonstrate how university-industry technology transfer can be achieved effectively by nurturing and bridging communities of practice amongst recipients of technology and stakeholders concerned with technology diffusion, productivity and economic development. Its empirical evidence is from an intervention initiative targeting two small-scale industries, namely fish farming and coffee production, in the Cauca region of Colombia. Results show how barriers to transfer have been overcome and the intervention’s design elements and outcomes are discussed.

The micro-politics of operational adjustment:veto players and the consolidation of demand in the NHS

Recent reports about procurement within the NHS have been highly critical. One problem identified in the reports is the fragmentation of NHS demand across an unnecessarily large number of suppliers. This fragmentation is said to increase transaction costs, reduce opportunities for scale economies and reduce NHS leverage over suppliers. It has been suggested, therefore, that an important way of improving procurement in the NHS is the better consolidation of demand with a lower number of preferred suppliers. However, such a policy, because it will create ‘winners’ and ‘losers’ within NHS organisations, has political as well as technical and practical ramifications. In this article, the authors present a model, the Veto Players Model, in order to assist managers to address these political ramifications. In the article, the authors not only demonstrate the utility of this model with regard to demand consolidation policies, but also argue that the model provides useful lessons for change management initiatives more generally.

Micro-fabrication of advanced photonic devices by means of direct point-by-point femtosecond inscription in silica

We present recent results on experimental micro-fabrication and numerical modeling of advanced photonic devices by means of direct writing by femtosecond laser. Transverse inscription geometry was routinely used to inscribe and modify photonic devices based on waveguiding structures. Typically, standard commercially available fibers were used as a template with a pre-fabricated waveguide. Using a direct, point-by-point inscription by infrared femtosecond laser, a range of fiber-based photonic devices was fabricated including Fiber Bragg Gratings (FBG) and Long Period Gratings (LPG). Waveguides with a core of a couple of microns, periodic structures, and couplers have been also fabricated in planar geometry using the same method.