Fibroblast contractility and actin organization are stimulated by microtubule inhibitors

Despite considerable evidence that cytoplasmic microtubules play some role in guiding or controlling the locomotion of tissue cells, the nature of this control is not understood. In particular, little is known about the role of microtubules in the exertion of propulsive 'traction' forces, or about microtubule effects on the organization of the cytoplasmic actin stress fibers. In this study, the silicone rubber substratum technique was used in combination with fluorescence microscopy in order to observe the effects of microtubule-depolymerizing drugs on the contractile strength and organization of cytoplasmic actin networks. Perfusion with a variety of microtubule poisons (either colcemid, nocodazole or vinblastine) was found to cause a rapid and substantial strengthening of fibroblast contractility. This was demonstrated in two established fibroblast cell lines, as well as in primary cultures of rat gingival fibroblasts and embryonic chick heart fibroblasts. Treatment with the drug taxol, which promotes microtubule assembly, was found to prevent the strengthening effects of the microtubule inhibitors. It was also found that the disruption of actin stress fibers by the phorbol ester tumor promoter, TPA, is reversed by microtubule poisons: stress fibers reform within 30 min of the addition of the microtubule drugs, despite the continued presence and activity of the TPA. Several possible mechanisms are considered, including the idea that microtubule assembly normally exerts a pushing force, which counterbalances part of the contractile force exerted by the actin stress fibers. However, the mechanism that seems best to account for the observations is that microtubules modulate, in an inhibitory fashion, the contractility and the state of organization of cytoplasmic actin

Scraping the Social? Issues in live social research

What makes scraping methodologically interesting for social and cultural research? This paper seeks to contribute to debates about digital social research by exploring how a ‘medium-specific’ technique for online data capture may be rendered analytically productive for social research. As a device that is currently being imported into social research, scraping has the capacity to re-structure social research, and this in at least two ways. Firstly, as a technique that is not native to social research, scraping risks to introduce ‘alien’ methodological assumptions into social research (such as an pre-occupation with freshness). Secondly, to scrape is to risk importing into our inquiry categories that are prevalent in the social practices enabled by the media: scraping makes available already formatted data for social research. Scraped data, and online social data more generally, tend to come with ‘external’ analytics already built-in. This circumstance is often approached as a ‘problem’ with online data capture, but we propose it may be turned into virtue, insofar as data formats that have currency in the areas under scrutiny may serve as a source of social data themselves. Scraping, we propose, makes it possible to render traffic between the object and process of social research analytically productive. It enables a form of ‘real-time’ social research, in which the formats and life cycles of online data may lend structure to the analytic objects and findings of social research. By way of a conclusion, we demonstrate this point in an exercise of online issue profiling, and more particularly, by relying on Twitter to profile the issue of ‘austerity’. Here we distinguish between two forms of real-time research, those dedicated to monitoring live content (which terms are current?) and those concerned with analysing the liveliness of issues (which topics are happening?)

Multistate Switching of Spin Selectivity in Electron Transport through Light-Driven Molecular Motors

It is established that electron transmission through chiral molecules depends on the electron's spin. This phenomenon, termed the chiral-induced spin selectivity (CISS), effect has been observed in chiral molecules, supramolecular structures, polymers, and metal-organic films. Which spin is preferred in the transmission depends on the handedness of the system and the tunneling direction of the electrons. Molecular motors based on overcrowded alkenes show multiple inversions of helical chirality under light irradiation and thermal relaxation. The authors found here multistate switching of spin selectivity in electron transfer through first generation molecular motors based on the four accessible distinct helical configurations, measured by magnetic-conductive atomic force microscopy. It is shown that the helical state dictates the molecular organization on the surface. The efficient spin polarization observed in the photostationary state of the right-handed motor coupled with the modulation of spin selectivity through the controlled sequence of helical states, opens opportunities to tune spin selectivity on-demand with high spatio-temporal precision. An energetic analysis correlates the spin injection barrier with the extent of spin polarization

Prefigurative politics between ethical practice and absent promise

'Prefigurative politics' has become a popular term for social movements' ethos of unity between means and ends, but its conceptual genealogy has escaped attention. This article disentangles two components: an ethical revolutionary practice, chiefly indebted to the anarchist tradition, which fights domination while directly constructing alternatives; and prefiguration as a recursive temporal framing, unknowingly drawn from Christianity, in which a future radiates backwards on its past. Tracing prefiguration from the Church Fathers to politicised re-surfacings in the Diggers and the New Left, I associate it with Koselleck's 'process of reassurance' in a pre-ordained historical path. Contrasted to recursive prefiguration are the generative temporal framings couching defences of means-ends unity in the anarchist tradition. These emphasised the path dependency of revolutionary social transformation and the ethical underpinnings of anti-authoritarian politics. Misplaced recursive terminology, I argue, today conveniently distracts from the generative framing of means-ends unity, as the promise of revolution is replaced by that of environmental and industrial collapse. Instead of prefiguration, I suggest conceiving of means-ends unity in terms of Bloch's 'concrete utopia', and associating it with 'anxious' and 'catastrophic' forms of hope

Life remade: critical animation in the digital age

Introduction to Special Issue of animation: an interdisciplinary journal. Animation and contemporary life are enmeshed like never before. A growing number of the media images we consume are in animated form (from fully animated features to CGI laden blockbusters and advertisements); recourse to common animation software and aesthetic approaches significantly blur the lines between previously distinct artistic and design practices (from video games, to special effects, to architecture and contemporary art); and through techniques of computational modelling and visualization, animation is increasingly fundamental to processes of knowledge production and the creation of various modes or elements of life. This appears therefore to be a particularly 'critical' moment to ponder animation's expanded cultural and political role. This special issue also provides an opportunity to consider animation's own powers of critique – the ways in which the digital animated image is increasingly being deployed explicitly as a means of intervening in social and political arenas ranging from human rights advocacy to ecological activism. And finally, we hope this collection of essays serves to further the already rich examination of the politics of more traditional forms of animation in the current digital age. This special issue thus builds upon recent scholarship that has already begun to contend with animation's expanded presence and its inherent political and critical significance..

Disenchanting secularism (or the cultivation of soul) as pedagogy in resistance to populist racism and colonial structures in the academy

This paper explores pedagogic strategies for resisting the racism of contemporary populism and age-old coloniality through challenging secularism in the academy, especially in social theory. Secularism sustains racism and imperialism in the contemporary academy and is inscribed, in part, through the norms of social theory. Post-secular social theory has been positioned by some as the decolonial answer, but often replicates the most problematic aspects of secularism. Whereas post-secularism affirms the previously denigrated side of the secular vs religious dualism, I am more interested in unworking those classificatory schemas, setting the critical thought of religious teachers in relation with ‘secular’ social and political theorists such that boundaries erode. The ambition in this is to resist the hierarchical orderings of knowledge that pit Islamic, indigenous, and feminised subjectivity as backwards, dangerous or intrinsically inferior to secular, Christian, rational knowledge. It is also to disenchant the secular Gods (progress, money, growth, health) and hold open space for critical play in relation to the transcendental - to create a permissive, legitimising, space for students’ spiritual dimension, conocimiento, or the cultivation of soul. The paper draws theoretical inspiration from Gloria Anzaldúa, Gayatri Chakravorty Spivak, and Sylvia Wynter. It also draws on a practical experiment in disenchanting secularism through teaching an undergraduate module in social theory called Capitalism and Religion