Diabetic retinopathy is the major cause of vision loss in middle-aged adults. Alteration of the blood-retinal barrier (BRB) is the hallmark of diabetic retinopathy and, subsequently, hypoxia may result in retinal neovascularization. Tight control of systemic factors such as blood glucose, blood pressure and blood lipids is essential in the management of this disease. Vascular endothelial growth factor (VEGF) is one of the most important factors responsible for alteration of the BRB. The introduction of anti-VEGF agents has revolutionized the therapeutic strategies used in people with diabetic retinopathy, and the use of laser therapy has been modified. In the present article, we examine the clinical features and pathophysiology of diabetic retinopathy and review the current status of new treatment recommendations for this disease, and also explore some possible future therapies. Keywords: blood-retinal barrier, diabetes complications, diabetes mellitus, diabetic retinopathy, vascular endothelial growth factor [2,3]. Although laser photocoagulation therapy has been the mainstay of management therapy in addition to control of systemic factors, the use of intravitreal anti-vascular endothelial growth factor (VEGF) agents and steroids in recent years has revolutionized the management of diabetic macular oedema. In the present review, we will discuss the pathogenesis of diabetic retinopathy and the treatment strategies currently available for the treatment of diabetic macular oedema and proliferative diabetic retinopathy (PDR; Table 1). Clinical FeaturesThe earliest clinical lesions of diabetic retinopathy are microaneurysms, or focal dilations of retinal microvessels seen as deep red dots, mainly in the posterior pole. Usually these lesions appear and disappear over time and cause no symptoms themselves. Microaneurysms are present in almost all people with type 1 diabetes of 20 years duration, and in 80% of people with type 2 diabetes [4,5]. Based on the absence or presence of new vessels, diabetic retinopathy is classified

Heterogeneous computing (HC) systems composed of interconnected machines with varied computational capabilities often operate in environments where there may be inaccuracies in the estimation of task execution times. Makespan (defined as the completion time for an entire set of tasks) is often the performance feature that needs to be optimized in such systems. Resource allocation is typically performed based on estimates of the computation time of each task on each class of machines. Hence, it is important that makespan be robust against errors in computation time estimates. In this research, the problem of finding a static mapping of tasks to maximize the robustness of makespan against the errors in task execution time estimates given an overall makespan constraint is studied. Two variations of this basic problem are considered: (1) where there is a given, fixed set of machines, (2) where an HC system is to be constructed from a set of machines within a dollar cost constraint. Six heuristic techniques for each of these variations of the problem are presented and evaluated.

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