An agent-based model of the response to angioplasty and bare-metal stent deployment in an atherosclerotic blood vessel

Purpose: While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques. The presented model is intended to demonstrate the body's response to the intervention and to explore how different vessel geometries or stent arrangements may affect restenosis development. Methods: The model was created on a two-dimensional grid space. It utilizes the post-procedural vessel lumen diameter and stent information as its input parameters. The simulation starting point of the model is an atherosclerotic vessel after an angioplasty and stent implantation procedure. The model subsequently generates the final lumen diameter, percent change in lumen cross-sectional area, time to lumen diameter stabilization, and local concentrations of inflammatory cytokines upon simulation completion. Simulation results were directly compared with the results from serial imaging studies and cytokine levels studies in atherosclerotic patients from the relevant literature. Results: The final lumen diameter results were all within one standard deviation of the mean lumen diameters reported in the comparison studies. The overlapping-stent simulations yielded results that matched published trends. The cytokine levels remained within the range of physiological levels throughout the simulations. Conclusion: We developed a novel computational model that successfully simulated the development of restenosis in a blood vessel following an angioplasty and bare-metal stent deployment based on the characteristics of the vessel crosssection and stent. A further development of this model could ultimately be used as a predictive tool to depict patient outcomes and inform treatment options. © 2014 Curtin, Zhou

Recent advances in understanding hypertension development in sub-Saharan Africa

Consistent reports indicate that hypertension is a particularly common finding in black populations. Hypertension occurs at younger ages and is often more severe in terms of blood pressure levels and organ damage than in whites, resulting in a higher incidence of cardiovascular disease and mortality. This review provides an outline of recent advances in the pathophysiological understanding of blood pressure elevation and the consequences thereof in black populations in Africa. This is set against the backdrop of populations undergoing demanding and rapid demographic transition, where infection with the Human Immunodeficiency Virus predominates, and where under and over-nutrition coexist. Collectively, recent findings from Africa illustrate an increased lifetime risk to hypertension from foetal life onwards. From young ages black populations display early endothelial dysfunction, increased vascular tone and reactivity, microvascular structural adaptions, as well as increased aortic stiffness resulting in elevated central and brachial blood pressures during the day and night, when compared to whites. Together with knowledge on the contributions of sympathetic activation and abnormal renal sodium handling, these pathophysiological adaptations result in subclinical and clinical organ damage at younger ages. This overall enhanced understanding on the determinants of blood pressure elevation in blacks encourages (a) novel approaches to assess and manage hypertension in Africa better, (b) further scientific discovery to develop more effective prevention and treatment strategies, and (c) policymakers and health advocates to collectively contribute in creating health-promoting environments in Africa

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is the most common acute hyperglycaemic emergency in people with diabetes mellitus. A diagnosis of DKA is confirmed when all of the three criteria are present — ‘D’, either elevated blood glucose levels or a family history of diabetes mellitus; ‘K’, the presence of high urinary or blood ketoacids; and ‘A’, a high anion gap metabolic acidosis. Early diagnosis and management are paramount to improve patient outcomes. The mainstays of treatment include restoration of circulating volume, insulin therapy, electrolyte replacement and treatment of any underlying precipitating event. Without optimal treatment, DKA remains a condition with appreciable, although largely preventable, morbidity and mortality. In this Primer, we discuss the epidemiology, pathogenesis, risk factors and diagnosis of DKA and provide practical recommendations for the management of DKA in adults and children

Deployment of a large-scale soil monitoring geosensor network

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate

Deployment of a Large-Scale Soil Moisture Geosensor Network- Experience and Lessons Learnt

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate

Deployment of a large-scale soil monitoring geosensor network

We provide an overview of our practical experience with developing a distributed sensor network to monitor soil response to climate change and increase our understanding of the complex interactions of the surrounding ecological, biogeochemical and meteorological processes. The network consists of seven sites with unique topographical, and land-use characteristics, spread across a large area in the state of New Hampshire (US). The system was designed to measure soil moisture, soil CO2 efflux and make other ancillary measurements (air temperature, precipitation, wind speed etc.). The system design encompasses sensor and hardware selection, customization and the overcoming design constraints such as the need to operate a power hungry sensing system at remote locations with access only to solar power. The data we collect streams to the web as an outreach and teaching resource, provides input to ecosystem models used to predict how ecosystems in the region will respond to climate and land-use change, and directly monitors soil properties and processes in a changing climate