Real-time imaging of novel spatial and temporal responses to photodynamic stress.

Cells subjected to various forms of stress have been shown to induce bystander responses in nontargeted cells, thus extending the stress response to a larger population. However, the mechanism(s) of bystander responses remains to be clearly identified, particularly for photodynamic stress. Oxidative stress and cell viability were studied on the spatial and temporal levels after photodynamic targeting of a subpopulation of EMT6 murine mammary cancer cells in a multiwell plate by computerized time-lapse fluorescence microscopy. In the targeted population a dose-dependent loss of cell viability was observed in accordance with increased oxidative stress. This was accompanied by increased oxidative stress in bystander populations but on different time scales, reaching a maximum more rapidly in targeted cells. Treatment with extracellular catalase, or the NADPH oxidase inhibitor diphenyleneiodinium, decreased production of reactive oxygen species (ROS) in both populations. These effects are ascribed to photodynamic activation of NADPH-oxidase in the targeted cells, resulting in a rapid burst of ROS formation with hydrogen peroxide acting as the signaling molecule responsible for initiation of these photodynamic bystander responses. The consequences of increased oxidative stress in bystander cells should be considered in the overall framework of photodynamic stress.

Spatial attentional bias as a marker of genetic risk, symptom severity, and stimulant response in ADHD

Attention-deficit hyperactivity disorder (ADHD) is a heritable childhood onset disorder that is marked by variability at multiple levels including clinical presentation, cognitive profile, and response to stimulant medications. It has been suggested that this variability may reflect etiological differences, particularly, at the level of underlying genetics. This study examined whether an attentional phenotype-spatial attentional bias could serve as a marker of symptom severity, genetic risk, and stimulant response in ADHD. A total of 96 children and adolescents with ADHD were assessed on the Landmark Task, which is a sensitive measure of spatial attentional bias. All children were genotyped for polymorphisms (30 untranslated (UTR) and intron 8 variable number of tandem repeats (VNTRs)) of the dopamine transporter gene (DAT1). Spatial attentional bias correlated with ADHD symptom levels and varied according to DAT1 genotype. Children who were homozygous for the 10-repeat allele of the DAT1 30-UTR VNTR displayed a rightward attentional bias and had higher symptom levels compared to those with the low-risk genotype. A total of 26 of these children who were medication naive performed the Landmark Task at baseline and then again after 6 weeks of stimulant medication. Left-sided inattention (rightward bias) at baseline was associated with an enhanced response to stimulants at 6 weeks. Moreover, changes in spatial bias with stimulant medications, varied as a function of DAT1 genotype. This study suggests an attentional phenotype that relates to symptom severity and genetic risk for ADHD, and may have utility in predicting stimulant response in ADHD.

Dopaminergic genotype biases spatial attention in healthy children

In everyday life, our sensory system is bombarded with visual input and we rely upon attention to select only those inputs that are relevant to behavioural goals. Typically, humans can shift their attention from one visual field to the other with little cost to perception. In cases of, unilateral neglect', however, there is a persistent bias of spatial attention towards the same side as the damaged cerebral hemisphere. We used a visual orienting task to examine the influence of functional polymorphisms of the dopamine transporter gene (DAT1) on individual differences in spatial attention in normally developing children. DAT1 genotype significantly influenced spatial bias. Healthy children who were homozygous for alleles that influence the expression of dopamine transporters in the brain displayed inattention for left-sided stimuli, whereas heterozygotes did not. Our data provide the first evidence in healthy individuals of a genetically mediated bias in spatial attention that is related to dopamine signalling.

Retrodirective Antenna Spatial Data Protection

In this letter, we show how a 2.4-GHz retrodirective array operating in a multipath rich environment can be utilized in order to spatially encrypt digital data. For the first time, we give experimental evidence that digital data that has no mathematical encryption applied to it can be successfully recovered only when it is detected with a receiver that is polarization-matched to that of a reference continuous-wave (CW) pilot tone signal. In addition, we show that successful detection with low bit error rate (BER) will only occur within a highly constrained spatial region colocated close to the position of the CW reference signal. These effects mean that the signal cannot be intercepted and its modulated data recovered at locations other than the constrained spatial region around the position from which the retrodirective communication was initiated.

‘A system that works for the sea’? Exploring Stakeholder Engagement in Marine Spatial Planning

This paper aims to contribute to the current debate on Marine Spatial Planning (MSP) by exploring the issue of stakeholder engagement. MSP is an emergent policy field that is subject to an increasing body of research, yet the role, scope and nature of participatory engagement within the process remains a neglected topic. This paper briefly reviews the nature of the ‘marine problem’, to which MSP is seen to be the response and describes the emergence of MSP policy in the UK with specific emphasis on participatory aspects. Drawing on the experience of terrestrial planning it discusses the potential benefits of stakeholder engagement in MSP and highlights some of the key issues that need to be taken into account when shaping stakeholder input into the process. It then goes on to describe the findings from a series of interviews with key stakeholders in the Irish Sea Region, which suggest that we need to develop a more critical and deeper understanding of how various interests frame the ‘marine problem’, and how they see their role in shaping the form of the MSP process. This highlights the importance of encouraging stakeholder involvement in MSP, the need to develop a shared vision of a ‘sea interest’. Priorities are then set for research to support this important policy agenda.

Troubled Geographies: A Spatial History of Religion and Society in Ireland

Ireland’s landscape is marked by fault lines of religious, ethnic, and political identity that have shaped its troubled history. Troubled Geographies maps this history by detailing the patterns of change in Ireland from 16th century attempts to “plant” areas of Ireland with loyal English Protestants to defend against threats posed by indigenous Catholics, through the violence of the latter part of the 20th century and the rise of the “Celtic Tiger.” The book is concerned with how a geography laid down in the 16th and 17th centuries led to an amalgam based on religious belief, ethnic/national identity, and political conviction that continues to shape the geographies of modern Ireland. Troubled Geographies shows how changes in religious affiliation, identity, and territoriality have impacted Irish society during this period. It explores the response of society in general and religion in particular to major cultural shocks such as the Famine and to long term processes such as urbanization.