The role of O-GlcNAc signaling in the pathogenesis of diabetic retinopathy

Diabetic retinopathy is a leading cause of blindness worldwide. Despite laser and surgical treatments, antiangiogenic and other therapies, and strict metabolic control, many patients progress to visual impairment and blindness. New insights are needed into the pathophysiology of diabetic retinopathy in order to develop new methods to improve the detection and treatment of disease and the prevention of blindness. Hyperglycemia and diabetes result in increased flux through the hexosamine biosynthetic pathway, which, in turn, results in increased PTM of Ser/Thr residues of proteins by O-linked β-N-acetylglucosamine (O-GlcNAc). O-GlcNAcylation is involved in regulation of many nuclear and cytoplasmic proteins in a manner similar to protein phosphorylation. Altered O-GlcNAc signaling has been implicated in the pathogenesis of diabetes and may play an important role in the pathogenesis of diabetic retinopathy. The goal of this review is to summarize the biology of the hexosamine biosynthesis pathway and O-GlcNAc signaling, to present the current evidence for the role of O-GlcNAc signaling in diabetes and diabetic retinopathy, and to discuss future directions for research on O-GlcNAc in the pathogenesis of diabetic retinopathy.     

The design of a collision avoidance system for use by Pilots operating on the airport ramp and in taxiway areas

Ground collisions have serious implications from both a safety and a commercial perspective. This paper reports on human computer interaction (HCI) research related to the advancement of a collision avoidance system, for use by Pilots operating on the airport ramp and in taxiway areas. Primarily, this paper focuses on the key findings of this research and the emerging HCI design solution.     

State-space caching revisited

State-space caching is a verification technique for finite-state concurrent systems. It performs an exhaustive exploration of the state space of the system being checked while storing only all states of just one execution sequence plus as many other previously visited states as available memory allows. So far, this technique has been of little practical significance: it allows one to reduce memory usage by only twoo to three times, before an unacceptable blow-up of the run-time overhead sets in. The explosion of the run-time requirements is due to redundant multiple explorations of unstored parts of the state space. Indeed, almost all states in the state space of concurrent systems are typically reached several times during the search.In this paper, we present a method to tackle the main cause of this prohibitive state matching: the exploration of all possible interleavings of concurrent executions of the system which all lead to the same state. Then, we show that, in many cases, with this method, most reachable states are visited only once during state-space exploration. This enables one not to store most of the states that have already been visited without incurring too much redundant explorations of parts of the state space, and makes therefore state-space caching a much more attractive verification method. As an example, we were able to competely explore a state space of 250,000 states while storing simultaneously no more than 500 states and with only a three-fold increas of the run-time requirements.     

A mathematical model,implementation and study of a swarm system

The work reported in this paper is motivated towards the development of a mathematical model for swarm systems based on macroscopic primitives. A pattern formation and transformation model is proposed. The pattern transformation model comprises two general methods for pattern transformation, namely a macroscopic transformation method and a mathematical transformation method. The problem of transformation is formally expressed and four special cases of transformation are considered. Simulations to confirm the feasibility of the proposed models and transformation methods are presented. Comparison between the two transformation methods is also reported.     

Provision and maintenance of presence and immersion in hand‐held virtual reality through motion based interaction

Hand‐held devices are also becoming computationally more powerful and being equipped with special sensors and non‐traditional displays for diverse applications aside from just making phone calls. As such, it raises the question of whether realizing virtual reality, providing a minimum level of immersion and presence, might be possible on a hand‐held device capable of only relatively “small” display. In this paper, we propose that motion based interaction can widen the perceived field of view (FOV) more than the actual physical FOV, and in turn, increase the sense of presence and immersion up to a level comparable to that of a desktop or projection display based VR systems. We have implemented a prototype hand‐held VR platform and conducted two experiments to verify our hypothesis. Our experimental study has revealed that when a motion based interaction was used, the FOV perceived by the user for the small hand held device was significantly greater than (around 50%) the actual. Other larger display platforms using the conventional button or mouse/keyboard interface did not exhibit such a phenomenon. In addition, the level of user felt presence in the hand‐held platform was higher than or comparable to those in VR platforms with larger displays. We hypothesize that this phenomenon is related to and analogous to the way the human vision system compensates for differences in acuity resolution in the eye/retina through the saccadic activity. The paper demonstrates the distinct possibility of realizing reasonable virtual reality even with devices with a small visual FOV and limited processing power. Copyright © 2010 John Wiley & Sons, Ltd.     

Random walks with statistical shape prior for cochlea and inner ear segmentation in micro-CT images

A cochlear implant is an electronic device which can restore sound to completely or partially deaf patients. For surgical planning, a patient-specific model of the inner ear must be built using high-resolution images accurately segmented. We propose a new framework for segmentation of micro-CT cochlear images using random walks, where a region term estimated by a Gaussian mixture model is combined with a shape prior initially obtained by a statistical shape model (SSM). The region term can then take advantage of the high contrast between the background and foreground, while the shape prior guides the segmentation to the exterior of the cochlea and to less contrasted regions inside the cochlea. The prior is obtained via a non-rigid registration regularized by a statistical shape model. The SSM constrains the inner parts of the cochlea and ensures valid output shapes of the inner ear.     

Augmented reality-based remote coaching for fast-paced physical task

Virtual Reality - One popular application of augmented reality (AR) is the real-time guidance and training in which the AR user receives useful information by a remote expert. For relatively...