Evaluation of risks of cardiovascular disease from radiation exposure linked to computed tomography scans in the UK.

Epidemiological studies of patient populations have shown that high doses of radiation increase risks of cardiovascular disease (CVD). Results from a recent meta-analysis of 93 epidemiological studies covering a wide range of doses provided evidence of a causal association between radiation exposure and CVD, and indicated excess relative risk per Gy for maximum dose below 500 mGy or delivered at low dose rates. These doses cover the range of organ doses expected from multiple diagnostic computed tomography (CT) scans.

How much should we be concerned about cumulative effective doses in medical imaging?

The International Atomic Energy Agency issued a statement calling for action to strengthen the radiation protection of patients undergoing recurrent imaging. This followed reports of patients receiving cumulative effective doses over 100 mSv from multiple computed tomography examinations. In order to evaluate excess risks of cancer incidence among UK patients, data from an exposure management system covering three hospitals within one trust have been studied over 5½ years.

Potential risks of cardiovascular and cerebrovascular disease and cancer due to cumulative doses received from diagnostic CT scans?

Potential risks from radiation exposure on the development of cardiovascular and cerebrovascular disease are indicated by epidemiological studies. Medical exposures give the largest dose to the population from artificial sources, with cumulative doses from multiple CT scans being significant. Data on doses from scans performed on 12 CT scanners in three hospitals over a period of 5½ years, derived using Radimetricssoftware, have been reviewed for 105 757 patients.

Persistence and Spreading Speeds of Integro-Difference Equations with an Expanding or Contracting Habitat.

We study an integro-difference equation model that describes the spatial dynamics of a species in an expanding or contracting habitat. We give conditions under which the species disperses to a region of poor quality where the species eventually becomes extinct. We show that when the species persists in the habitat, the rightward and leftward spreading speeds are determined by c, the speed at which the habitat quality increases or decreases in time, as well as [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], which are formulated in terms of the dispersal kernel and species growth rates in both directions.

Bifurcations in a discrete time model composed of Beverton-Holt function and Ricker function.

We provide rigorous analysis for a discrete-time model composed of the Ricker function and Beverton-Holt function. This model was proposed by Lewis and Li [Bull. Math.

Using in situ Raman monitoring as a tool for rapid optimisation and scale-up of microwave-promoted organic synthesis: esterification as an example.

Microwave-promoted esterification reactions have been monitored using in situ Raman spectroscopy. Having optimised a reaction on a 23 mmol scale, it was transferred to a larger reaction vessel and scaled up to 0.26 mol, again with Raman monitoring.