AbstractThe metal chelating properties of flavonoids suggest that they may play a role in metal-overload diseases and all oxidative stress conditions involving transition ion. A detailed study has been made the ability to chelate iron (including Fe 3+ ) copper ions its dependence structure pH. The acid medium be important some pathological conditions. In addition, reduce their activity-structure relationships were also investigated. To fulfil these objectives, flavones (apigenin, luteolin,...

The antioxidant and prooxidant activities of flavonoids belonging to several classes were studied establish their structure-activity relationships against different oxidants. Special attention was paid the quercetin (flavone), taxifolin (flavanone) catechin (flavanol), which possess basic structures but same hydroxylation pattern (3,5,7,3',4'-OH). It found that these three exhibited comparable oxidants leading conclusion presence ortho -catechol group (3',4'-OH) in B-ring is determinant for...

Large-scale space projects rely on a thorough Assembly, Integration, and Verification (AIV) process to provide the upmost reliability spacecraft. While this has not traditionally been case with CubeSats, their increasing role in science technology led new verification approaches, including educational CubeSats. This work describes integration approach for ISTSat-1, which is an CubeSat from Instituto Superior Técnico Portugal that partially discards typical stage-gate spacecraft development...

The relative activities of some hydrogen-donating antioxidants were assessed by comparing their with that Trolox (Trolox equivalent antioxidant capacity, TEAC) for scavenging the ABTS radical cation (ABTS.+) generated in aqueous phase. We have verified, however, TEAC values may change concentration compounds and measuring times used. Not withstanding, do not differ significantly if kinetic curves ABTS.+ formation similar to Trolox. This is case ascorbic acid, whose values, determined using...

The antioxidant capacity of extracts Crataegus oxyacantha, Hamamelis virginiana, Hydrastis canadensis, plants native to Europe and North America which have long been used in herbal medicine for the treatment cardiac circulatory functions, has investigated. total potential conferred by all hydrogen donating antioxidants present these assessed ABTS assay relative order established. Gas chromatography coupled mass spectrometry (GC-MS) chemical identification volatile compounds extracts. GC-MS...

Opportunistic wireless sensor networks (WSNs) have recently been proposed as solutions for many remote monitoring problems. Many such problems, including environmental monitoring, involve large deployment scenarios with lower-than-average node density, well a long time scale and limited budgets. Traditional approaches designed conventional situations, thus not optimized these scenarios, entail unnecessary complexity larger costs. This paper discusses the issues related design test of...

Combining wireless sensor networks (WSNs) with delay-tolerant networking (DTN) has the potential to extend their use in a multitude of previously impossible applications. However, and despite numerous proposed solutions, there is still wide debate as how best route messages these and, more importantly, do it an energy-efficient way. This paper proposes CHARON (Convergent Hybrid-replication Approach Routing Opportunistic Networks), approach that focuses on maximizing efficiency addition...

Abstract Quantum key distribution is costly and, at the moment, offers low performance in space applications. Other more recent protocols could offer a potential practical solution to this problem. In work, preliminary optical payload design using commercial off-the-shelf elements for quantum communication downlink 3U CubeSat proposed. It shown that state emitter allows establishment of two types between satellite and ground station: keyless private communication. Numerical simulations are...

The main goal of this work is to characterise communications through body area networks (BANs), analysing how the human affects wireless links qualities. 802.15.4 MICAz motes were deployed on seven on-body locations four volunteers and a test-dummy. quality was monitored in order study channel behaviour. Results show that clearly modifies communication properties, introducing attenuations up 26 dB. Differences between male female subjects found be unimportant. Body posture performance,...

A flexible Wireless Sensor Network platform has been developed and deployed at the Instituto Superior Tecnico/Technical University of Lisbon (IST-TUL). This test-bed integrates multiple projects into a single network, creating an expandable that facilitates future developments. To achieve this flexibility, dedicated framework was developed, enabling fine-grained parameter control application programmability through centralised configuration panel. On top platform, four applications have...

A flexible Wireless Sensor Network platform for implementation of diverse applications has been developed and deployed at Instituto Superior Tecnico – Technical University Lisbon (IST-TUL). Since its initial deployment in 2007, this testbed grown steadily, supporting new nodes, experiments. However, some problems, which were solved on an ad hoc basis, becoming more serious as the network spanned throughout campus. Major issues, like global power management, have to be tackled not only with...

A flexible wireless sensor network platform for easier implementation of diverse applications has been developed and deployed at the Institute Superior Tecnico - Technical University Lisbon (IST-TUL). This test-bed integrates multiple projects into a single common network, thus creating an expandable that facilitates development future applications. To achieve this flexibility, dedicated software framework was not only provides centralized configuration panel is accessible over Internet,...

A new modular transport layer protocol for wireless sensor networks (WSNs) is proposed: WMTP - Wireless Modular Transport Protocol. This not only allows the simultaneous use of all main features commonly found in WSN protocols, namely congestion-control, fairness, and reliability, but also does so a fashion. way, application can choose to exactly that it requires. Additionally, provides set uncommon such as throttling, flow-control, quality- of-service, optional integration with...

The advances on wireless mesh networks are shifting the communications paradigm, where users can benefit from their cooperation to exchange information and make use of spectrum space, forming neighbourhood communities resources shared services distributed. This paper presents a modular cross-layer community management architecture, which considers that formed managed at different layers, physical application. It focus in more depth one its modules, implementing discovery mechanism designed...

This paper proposes an environmental monitoring application based on the concept of Wireless Sensor Networks (WSNs). The goal this is to enable, through measurement relevant parameters, constant evaluation state grass in different zones a golf course. systems currently installed most courses uses single weather station. station only gives general data about conditions region where course located and doesn't allow green keepers distinguish irrigation needs By continuously soil condition real...

As machine-to-machine networks become larger and more pervasive, manual configuration discovery of resources will intractable. It is in this context that we propose the RDL, a Resource Description Language represents uniform way describing embedded resources, allowing them to be shared enabling new class resource-aware applications. The RDL can describe wide range characterizing individual nodes or entire networks. contribute overcome performance issues dense mobility-driven problems highly...

Peer-to-peer (P2P) networks and mobile ad-hoc (MANET) share many similarities. However, building a P2P overlay network directly on top of MANET can lead to poor performance unless specific cross-layer optimization is adopted. We propose novel solution comprised routing protocol, middleware an inter-layer communication mechanism which facilitates application development while improving reducing resource usage when compared layering traditional unstructured system MANET.

This paper addresses a scenario where wireless sensor network (WSN) is used to implement real-time relative positioning system. Its goal obtain coordinates of objects (the WSN nodes) in which the nodes are generally moving relatively each other. To accomplish this, distance among measured and its position computed allowing representation their spatial distribution. The test platform uses Crossbow's motes special ultrasound (US) boards have been adapted. US thus process measure distances this...

Architectures for Wireless Sensor Networks platforms have not evolved as expected during the past decade. The monolithic principles of first nodes are still followed in new designs. architectures prepared to include upgrades such energy management modules or even more efficient communication units. This leads constraints on development protocols and applications, since software takes entire burden reconfigurability optimization that could be done by a modular architecture. In this work,...

A flexible Wireless Sensor Network platform for easier implementation of diverse applications has been developed and deployed at one the Institute Superior Tecnico - Technical University Lisbon (IST-TUL) campus. Since its initial deployment in 2007, this test-bed grown steadily, supporting new nodes, experiments. However, some problems, which were solved on an ad hoc basis, are becoming more serious as network spans throughout Major issues, like global power management, have to be tackled...