Electronic and photonic switching in the atm era

Broadband networks require high-capacity switches in order to properly manage large amounts of traffic fluxes. Electronic and photonic technologies are being used to achieve this objective both allowing different multiplexing and switching techniques. Focusing on the asynchronous transfer mode (ATM), the inherent different characteristics of electronics and photonics makes different architectures feasible. In this paper, different switching structures are described, several ATM switching architectures which have been recently implemented are presented and the implementation characteristics discussed. Three diverse points of view are given from the electronic research, the photonic research and the commercial switches. Although all the architectures where successfully tested, they should also follow different market requirements in order to be commercialised. The characteristics are presented and the architectures projected over them to evaluate their commercial capabilities.Peer ReviewedPostprint (published version

Web Tracking: Mechanisms, Implications, and Defenses

This articles surveys the existing literature on the methods currently used by web services to track the user online as well as their purposes, implications, and possible user's defenses. A significant majority of reviewed articles and web resources are from years 2012-2014. Privacy seems to be the Achilles' heel of today's web. Web services make continuous efforts to obtain as much information as they can about the things we search, the sites we visit, the people with who we contact, and the products we buy. Tracking is usually performed for commercial purposes. We present 5 main groups of methods used for user tracking, which are based on sessions, client storage, client cache, fingerprinting, or yet other approaches. A special focus is placed on mechanisms that use web caches, operational caches, and fingerprinting, as they are usually very rich in terms of using various creative methodologies. We also show how the users can be identified on the web and associated with their real names, e-mail addresses, phone numbers, or even street addresses. We show why tracking is being used and its possible implications for the users (price discrimination, assessing financial credibility, determining insurance coverage, government surveillance, and identity theft). For each of the tracking methods, we present possible defenses. Apart from describing the methods and tools used for keeping the personal data away from being tracked, we also present several tools that were used for research purposes - their main goal is to discover how and by which entity the users are being tracked on their desktop computers or smartphones, provide this information to the users, and visualize it in an accessible and easy to follow way. Finally, we present the currently proposed future approaches to track the user and show that they can potentially pose significant threats to the users' privacy.Comment: 29 pages, 212 reference

Guest editorial

http://www.sciencedirect.com/science/article/B6TYP-46RDF5H-2/1/4d892d8249d5d0271e6b0a8dc9bd23a

Reactive and proactive routing in labelled optical burst switching networks

Optical burst switching architectures without buffering capabilities are sensitive to burst congestion. The existence of a few highly congested links may seriously aggravate the network throughput. Proper network routing may help in congestion reduction. The authors focus on adaptive routing strategies to be applied in labelled OBS networks, that is, with explicit routing paths. In particular, two isolated alternative routing algorithms that aim at network performance improvement because of reactive route selection are studied. Moreover, a nonlinear optimisation method for multi-path source-based routing, which aims at proactive congestion reduction is proposed. Comparative performance results are provided and some implementation issues are discussed.Postprint (published version

Nanoemulsion as potential vehicles for transdermal delivery of pure phytopharmaceuticals and poorly soluble drug

Nanoemulsion (NE) is defined as an O/W or W/O emulsion producing a transparent product that has a droplet size from 20-200nm and does not have the tendency to coalesce. It is promising for transdermal delivery of drugs as an efficient route of drug administration. Several mechanisms have been proposed to explain the advantages of nanoemulsions for the transdermal delivery of drugs. In transdermal delivery, the goal of dosage design is to maximize the flux through the skin into systemic circulation. A useful strategy for improving percutaneous flux is to improve the concentration of drug or choose an appropriate vehicle for the transdermal delivery. The nanoemulsions system should be a promising vehicle due to powerful ability to deliver drug through skins. With these approaches, the aim of this present study is to review the potential of nanoemulsion formulation for transdermal delivery of pure phytopharmaceuticals and poorly soluble drugs. Some nanoemulsions have however exhibited sufficiently high level of stability for them to be proposed as vehicle for drug delivery. Using the transdermal route eliminates the side effects, increases patient compliance, avoids first-pass metabolism, enhance bioavailability and maintains the plasma drug level for a longer period of time.Keywords: Transdernmal, poorly soluble drug, phytopharmaceuticals, nanoemulsion

Prophylactic Role of Boerhaavia diffusa in Ethylene Glycol Induced Calcium Oxalate Urolithiasis

Introduction: Boerhaavia diffusa Linn. (Family: Nyctaginaceae) is a widely used plant in India and Brazil as a traditional medicine for treatment of urolithiasis and other urinary disorders.Objectives: The aim of this study was to evaluate the antiurolithic activity of Boerhaavia diffusa root aqueous extract (BDE) as prophylaxis for renal stones.Methods: In vitro calcium oxalate (CaOx) crystallization inhibitory effect of BDE was determined by measuring change in turbidity at 620nm on addition of sodium oxalate in the synthetic urine. In a rat model of urolithiasis, induced by adding 0.75% ethylene glycol (EG) in drinking water and effect of simultaneous treatment of BDE (100-200 mg/kg) was observed for 28 days.Results: BDE inhibited CaOx nucleation, aggregation and crystal formation in the synthetic urine in vitro on addition of NaOx. The lithogenic treatment caused polyuria, weight loss, hyperoxaluria and impairment of renal function which was prevented by BDE. Hyperoxaluria and CaOx crystaldeposition in the renal tubules caused by EG intake was prevented by BDE treatment.Conclusion: This study indicates that the antiurolithic activity of Boerhaavia diffusa extract possibly mediated through inhibition of CaOx crystallization, diuresis and hypo-oxaluria may justify its prophylactic use in urolithiasis