Autonomous object harvesting using synchronized optoelectronic microrobots

Optoelectronic tweezer-driven microrobots (OETdMs) are a versatile micromanipulation technology based on the application of light induced dielectrophoresis to move small dielectric structures (microrobots) across a photoconductive substrate. The microrobots in turn can be used to exert forces on secondary objects and carry out a wide range of micromanipulation operations, including collecting, transporting and depositing microscopic cargos. In contrast to alternative (direct) micromanipulation techniques, OETdMs are relatively gentle, making them particularly well suited to interacting with sensitive objects such as biological cells. However, at present such systems are used exclusively under manual control by a human operator. This limits the capacity for simultaneous control of multiple microrobots, reducing both experimental throughput and the possibility of cooperative multi-robot operations. In this article, we describe an approach to automated targeting and path planning to enable open-loop control of multiple microrobots. We demonstrate the performance of the method in practice, using microrobots to simultaneously collect, transport and deposit silica microspheres. Using computational simulations based on real microscopic image data, we investigate the capacity of microrobots to collect target cells from within a dissociated tissue culture. Our results indicate the feasibility of using OETdMs to autonomously carry out micromanipulation tasks within complex, unstructured environments

The Map of Vilnius Graffiti as an Indicator of Social Urban Change: the Case Study of Naujininkai Neighborhood

This article, theoretically based on socio-spatial concepts of Lefebvre, de Certeau and their further interpreta - tions at the New Urban Sociology school (by Gottdiener, Zukin and others), examines the spread of graffiti in the urban space of Vilnius, the change of the local graffiti map during the years 2010–2013 and the possible social implications of the spotted modification of urban landscape. The qualitative research of Vilnius graffiti – which is understood both as an urban practice and an illicit urban inscription – and the case of Naujininkai neighborhood in particular, is based on data obtained from 1) in-depth interviews with experienced graffiti artists, 2) observation of graffiti in public space and 3) visual urban ethnography. Naujininkai neighborhood was attributed by local graffiti writers to the urban periphery in Vilnius graffiti map in 2010. However in 2010–2013 the visual development of urban landscape in Naujininkai indicates the trend, bringing the neigh- borhood a little closer to the urban core