DnaG interacts with a linker region that joins the N- and C-domains of DnaB and induces the formation of 3-fold symmetric rings

Loading of the replicative ring helicase onto the origin of replication (oriC) is the final outcome of a well coordinated series of events that collectively constitute a primosomal cascade. Once the ring helicase is loaded, it recruits the primase and signals the switch to the polymerization mode. The transient nature of the helicase-primase (DnaB-DnaG) interaction in the Escherichia coli system has hindered our efforts to elucidate its structure and function. Taking advantage of the stable DnaB-DnaG complex in Bacillus stearothermophilus, we have reviewed conflicting mutagenic data from other bacterial systems and shown that DnaG interacts with the flexible linker that connects the N- and C-terminal domains of DnaB. Furthermore, atomic force microscopy (AFM) imaging experiments show that binding of the primase to the helicase induces predominantly a 3-fold symmetric morphology to the hexameric ring. Overall, three DnaG molecules appear to interact with the hexameric ring helicase but a small number of complexes with two and even one DnaG molecule bound to DnaB were also detected. The structural/functional significance of these data is discussed and a speculative structural model for this complex is suggested.

Modelling and analysing cargo screening processes: a project outline

The efficiency of current cargo screening processes at sea and air ports is unknown as no benchmarks exists against which they could be measured. Some manufacturer benchmarks exist for individual sensors but we have not found any benchmarks that take a holistic view of the screening procedures assessing a combination of sensors and also taking operator variability into account. Just adding up resources and manpower used is not an effective way for assessing systems where human decision-making and operator compliance to rules play a vital role. For such systems more advanced assessment methods need to be used, taking into account that the cargo screening process is of a dynamic and stochastic nature. Our project aim is to develop a decision support tool (cargo-screening system simulator) that will map the right technology and manpower to the right commodity-threat combination in order to maximize detection rates. In this paper we present a project outline and highlight the research challenges we have identified so far. In addition we introduce our first case study, where we investigate the cargo screening process at the ferry port in Calais.

A Utilitarian Perspective of Social and Medical Contributions to Three Illustrative Conditions, and Recent UK NHS Policy Initiatives

Background: To date debate concerning the relative merits of social and medical sciences has been largely academic. Aims: To outline and critically appraise a utilitarian approach to mental health research that reflects a critical realist perspective. Method: Consideration of the relative utility of differing approaches to illustrative ‘‘psychiatric’’ disorders, and recent policy initiatives. Results: Socially relevant outcomes of Bipolar Affective Disorder are determined by influences that operate independently of the characteristic instability of mood. There is now a highly specific and effective psychological treatment for Panic Disorder. Its benefits are still not fully exploited because of continuing lay and professional focus upon the condition’s social manifestations. Great numbers of people presenting in primary care are unhelpfully caused to adopt the role of ‘‘patient’’ due to practices limiting the professional response to a medical one. Such practices reflect public and professional perceptions of the nature of ‘‘mental health difficulties’’ much more than they do the achievements of medicine. Recent policy-supporting initiatives influencing UK NHS mental health services are much more likely to be supported by social sciences than by medical research. Conclusions: There is considerable scope for a contribution to applied mental health research from frameworks and methodologies that are rooted in a social sciences perspective.