One-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents

An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125I-labelled aryl compounds and SPECT radiotracers

Late stage iodination of biologically active agents using a one-pot process from aryl amines

A simple and effective one-pot tandem procedure that generates aryl iodides from readily available aryl amines via stable diazonium salts has been developed. The operationally simple procedure and mild conditions allow late-stage iodination of a wide range of aryl compounds bearing various functional groups and substitution patterns. A novel synthetic strategy involving the preparation of nitroaryl compounds followed by a chemoselective tin(II) dichloride reduction and the use of the one-pot diazotisation–iodination transformation was also developed. The general applicability of this approach was demonstrated with the preparation of a number of medicinally important compounds including CNS1261, a SPECT imaging agent of the N-methyl-D-aspartate (NMDA) receptor and IBOX, a compound used to detect amyloid plaques in the brain

The International Grid (iGrid): Empowering Global Research Community Networking Using High Performance International Internet Services

The Electronic Visualization Laboratory (EVL) at the University of Illinois at Chicago and Indiana University collaborated on a major research demonstration at the IEEE/ACM Supercomputing '98 (SC'98) conference in Orlando, Florida, November 7-13, 1998, to showcase the evolution and importance of global research community networking. Collaborators worked together to solve complex computational problems using advanced high-speed networks to access geographically-distributed computing, storage, and display resources. It is the collection of computing and communication resources that we refer to as the International Grid (iGrid). This paper presents an overview of the grid testbed, some of the underlying technologies used to enable distributed computing and collaborative problem solving, and descriptions of the applications. It concludes with recommendations for the future of global research community networking, based on the experiences of iGrid participants from the USA, Australia, Canada, Germany, Japan, The Netherlands, Russia, Switzerland, Singapore, and Taiwan

Varying spin state composition by the choice of capping ligand in a family of molecular chains: detailed analysis of magnetic properties of chromium(III) horseshoes

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Bleb-driven chemotaxis of Dictyostelium cells

Blebs and F-actin-driven pseudopods are alternative ways of extending the leading edge of migrating cells. We show that Dictyostelium cells switch from using predominantly pseudopods to blebs when migrating under agarose overlays of increasing stiffness. Blebs expand faster than pseudopods leaving behind F-actin scars, but are less persistent. Blebbing cells are strongly chemotactic to cyclic-AMP, producing nearly all of their blebs up-gradient. When cells re-orientate to a needle releasing cyclic-AMP, they stereotypically produce first microspikes, then blebs and pseudopods only later. Genetically, blebbing requires myosin-II and increases when actin polymerization or cortical function is impaired. Cyclic-AMP induces transient blebbing independently of much of the known chemotactic signal transduction machinery, but involving PI3-kinase and downstream PH domain proteins, CRAC and PhdA. Impairment of this PI3-kinase pathway results in slow movement under agarose and cells that produce few blebs, though actin polymerization appears unaffected. We propose that mechanical resistance induces bleb-driven movement in Dictyostelium, which is chemotactic and controlled through PI3-kinase

The quantified self: what counts in the neoliberal workplace

Implementation of quantified self technologies in workplaces relies on the ontological premise of Cartesian dualism with mind dominant over body. Contributing to debates in new materialism, we demonstrate that workers are now being asked to measure our own productivity and health and wellbeing in art-houses and warehouses alike in both the global north and south. Workers experience intensified precarity, austerity, intense competition for jobs, and anxieties about the replacement of labour-power with robots and other machines as well as, ourselves replaceable, other humans. Workers have internalized the imperative to perform, a subjectification process as we become observing, entrepreneurial subjects and observed, objectified labouring bodies. Thinking through the implications of the use of wearable technologies in workplaces, this article shows that these technologies introduce a heightened Taylorist influence on precarious working bodies within neoliberal workplaces

Workshopping the revolution? On the phenomenon of joker training in the Theatre of the Oppressed

The article brings together observations and insights on the emerging phenomenon of training the trainers, also known as joker training in the Theatre of the Oppressed (TO). The concerns raised in this article are twofold: first, how does the modularised, workshop format of joker training affect the core principles of TO? Second, what are the implications of professionalising the work of the joker? These questions relate to the critique of ‘creative industries’ and debates around precarisation that profoundly impact arts and humanities education in contemporary Europe. They also serve as a call to interrogate concepts central to TO, such as participation, empowerment and community, in terms of how these concepts are appropriated and made docile in the increasingly neoliberal environment of European cultural and educational policies. The article proposes that a training in TO must view the dissemination of techniques and methods of joker practice as inseparable from a deep commitment to a ‘conscientised’ understanding of the complex social problems that the theatre seeks to address. The focus on a technical training alone bears the danger of reinforcing Freire's ‘banking method’ of pedagogy, which is counterproductive to the political objectives of TO. The article observes that professional jokers work in precarious conditions far removed from the promises of the economic rewards of creative enterprise. The proliferation of project-based freelance work creates a situation where jokers tend to become de-territorialised and alienated from actual problems, thus propagating biographic and short-term approaches to systemic contradictions. The study aims to problematise these issues and contribute to a debate that might lead to politically and professionally viable paths for the future of TO

Novel semiconductor based light sources

The research described in this thesis relates to the design, fabrication and testing of novel semiconductor-based light sources that have been designed for the generation of infra-red light. The thesis is formatted to account for two distinct components of my work, where the first part concerns sources producing coherent light by direct laser emission, notably, ultrashort-pulse quantum-dot lasers. These types of lasers continue to show considerable promise as efficient, compact sources of ultrashort pulses with durations of hundreds of femtoseconds, while giving rise to unique and interesting electronic properties such as low lasing thresholds through the quantum nature of their density of states. At the outset a study of the most relevant aspects of the lasing dynamics of an optically pumped quantum-dot laser is outlined. Pumping of the device with intense discrete optical pulses leads to output from multiple electronic states, each having a characteristic wavelength and temporal properties. I show that pulses produced by excited-state emission have shorter durations (24 ps) and arrive earlier in time than those due to transitions from the ground state, which themselves have durations of around 180 ps. Investigations are then made on two different mode-locked quantum-dot laser systems. One is an all-quantum-dot external-cavity laser that is mode locked using a quantum-dot SESAM device at a repetition frequency of 860 MHz with output power approaching 20 mW. This is followed by a study of a monolithic two-section quantum-dot laser that is mode locked stably in a wide temperature range of 20°C to 70°C. The excellent performance characteristics presented serve to demonstrate both the versatility of quantum-dot material as components in mode-locked laser systems and the temperature stability of such laser devices. The second part of the thesis relates to structures that are designed to take advantage of nonlinear frequency conversion in GaAs-based semiconductors. This material system possesses a nonlinear coefficient of ~170 pm/V and is transparent from around 0.9 μm through to 17 μm, making it attractive for the realisation of a new class of efficient, integrable, quasi-phase-matched, optical parametric oscillator devices. Initially, ion implantation is utilised as a vector to create a periodically-switched nonlinear ridge waveguided device. The observation is made that in the course of implantation the transmissive properties of the device are severely degraded. Unfortunately, the high losses incurred, which reached 250 dB/cm, could not be removed without also destroying the modulation in nonlinearity. During the course of this investigation, significant technological advances were made in the production of orientation-patterned GaAs structures. By recognising the elegance and potential of this new orientation-patterned (OP) methodology, a study of its implications and applicability in the context of my project is initiated