9,316 research outputs found

    Towards predictive modelling of near-edge structures in electron energy loss spectra of AlN based ternary alloys

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    Although electron energy loss near edge structure analysis provides a tool for experimentally probing unoccupied density of states, a detailed comparison with simulations is necessary in order to understand the origin of individual peaks. This paper presents a density functional theory based technique for predicting the N K-edge for ternary (quasi-binary) nitrogen alloys by adopting a core hole approach, a methodology that has been successful for binary nitride compounds. It is demonstrated that using the spectra of binary compounds for optimising the core hole charge (0.35 e0.35\,\mathrm{e} for cubic Ti1−x_{1-x}Alx_xN and 0.45 e0.45\,\mathrm{e} for wurtzite Alx_xGa1−x_{1-x}N), the predicted spectra evolutions of the ternary alloys agree well with the experiments. The spectral features are subsequently discussed in terms of the electronic structure and bonding of the alloys.Comment: 11 pages, 9 figures, 1 tabl

    Epidural Abscess Related to Brucellar Spondylodiscitis Diagnosis by Polymerase Chain Reaction (PCR)

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    The localized forms of brucellosis, particularly osteoarticular, by their symptomatology usually nonspecific, still continue to be a diagnosis challenge, being fundamental to raise a high degree of suspicion based on a careful epidemiological history. The authors describe the case of a 69 year old farmer that was admitted due to an insidious lower back pain with irradiation to the left lower limb accompanied by nocturnal sweating, anorexia and weight loss. The imaging studies revealed a spondylodiscitis in L3-L4 with an associated epidural abscess. The diagnosis of brucellosis was brought on by the occupational exposure to sheep and was confirmed by a positive PCR to Brucella in the product gathered by aspiration from the epidural abscess and also by the serology (ELISA and Rose Bengal). Despite the initial therapy with doxycycline, rifampicin and gentamycin (the last one for 1 week), the patient had a clinical and imagiologic worsening, determining surgical decompression. After the surgery, antiobiotherapy with doxycyline and rifampicin was maintained and a cycle of gentamicin was started, this time for a month, with a favorable clinical evolution.info:eu-repo/semantics/publishedVersio

    Occlusion technique in swimming: a training method to improve exchange block time in swimming relays

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    Swimming relay events have the concern regarding a good start is shared between the incoming and outgoing swimmers. The aim of this study was to evaluate changes in exchange block time (eBT) for swimming relay events as a result of a four-week training program using the occlusion technique. MeThodS: Twenty-eight national swimmers, 12 males (age: 17±1.83 years) and 16 females (age: 19.94±5.65 years) participated in this study. Subjects were required to undergo a training program on visual perception in relay swimming over the course of four weeks; they watched videos corresponding to the last movements of a swimmer during a 4×100m freestyle relay event. The videos were presented with temporal occlusion corresponding to predetermined approaching distances (7.5 m, 5.0 m, and 2.5 m). Swimmers were required to simulate a typical position for exiting the block and to estimate the time-to-contact of the incoming swimmer. The eBT was collected during a real 4×100-m freestyle competition before and after the application of the training program. RESULTS: Female swimmers showed a decreased in EBT, with an improvement of 1.42%, despite there not being a signifcant difference (p=0.68). The male swimmers had a higher improvement in eBT after the training, with a decrease of 13.34% (p=0.68). coNcluSioNS: Visual perception practice using video occlusion techniques seems to have a positive effect. on eBT in swimming relay events, particularly in female swimmersinfo:eu-repo/semantics/publishedVersio

    FRACTAL DIMENSION AND HUMAN AQUATIC LOCOMOTION

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    The aim was to investigate the fractal properties of human swimming and analyze its relationship with swimming kinematics. Eighty-two male swimmers from the local level up to World-ranked athletes undertook a set of 3x25m maximal trials at Front-Crawl. Fractal dimension (D) was calculated from the speed-time series collected with a speedo-meter. It was also calculated the speed fluctuation as an energy cost estimator. Human swimming showed fractal properties (1?D?2). The relationship between D and dv was very high analyzed in absolute values (R2=0.88; s=0.18;

    RF CMOS Wireless Implantable Microsystem for Sacral Roots Stimulation with On-Chip Antenna and Far-Field Wireless Powering

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    The use of heterogeneous integration technologies is the path for the development of further miniaturized, smarter, and energy autonomous microdevices, which are required to tackle the challenge of monitoring and/or control the health condition of everyone, everywhere. The interaction with human body requires the use of flexible materials, while the electronic component are based on rigid materials, like silicon substrates. Also, once inside the human body, it is desirable to have a wireless link for data communication, as well for RF powering, using energy harvesting techniques or dedicated powering RF links. This paper shows the design of an implantable microsystem to be used for functional electrical stimulation of sacral roots. The proposed system includes flexible electrodes, integrated with an RF CMOS chip, which is powered by a wireless link through an efficient on-chip antenna.This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/62608/2009), FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

    A new miniature cryptic species of the seasonal killifish genus Spectrolebias from the Tocantins River basin, central Brazil (Cyprinodontiformes, Aplocheilidae)

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    The miniature seasonal killifish Spectrolebias costae, first described for the middle Araguaia River basin, has been also recorded from two areas in the middle Tocantins River basin, from where male specimens exhibit some differences in their colour pattern. Analyses directed to species delineation (GMYC and bPTP), using a fragment of the mitochondrial gene COI, strongly support two species, S. costae from the Araguaia River basin and a new species from the Tocantins River basin. Spectrolebias gracilis sp. n. is described on the basis of specimens collected from two localities separated by about 530 km, Canabrava River floodplains near Alvorada do Tocantins and Tocantins River floodplains near Palmeirante. Field inventories were unsuccessful in finding additional populations in the region, which is attributed to the high environmental degradation, including several large dams that have permanently inundated typical killifish habitats. Spectrolebias gracilis is member of a clade also including S. costae, S. inaequipinnatus, and S. semiocellatus, diagnosed by having the dorsal and anal fins in males with iridescent dots restricted to their basal portion, caudal fin in males hyaline, and caudal-fin base with two pairs of neuromasts. Within this clade, a single miniaturisation event is supported for the most recent common ancestor of the subclade comprising S. costae and S. gracilis, which differ from other congeners by reaching only about 20 mm standard length as maximum adult size

    Soluble starch and composite starch Bioactive Glass 45S5 particles : synthesis, bioactivity, and interaction with rat bone marrow cells

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    For many biomedical applications, biodegradable and simultaneously bioactive materials are desired. These materials should at the same time be able to support cell function and co-exist with the organism without triggering a relevant immune response. In this work, the synthesis as well as the bioactivity evaluation of newly developed polymer soluble potato starch and composite (with Bioactive Glass 45S5) micron-size particles are reported. An extremely interesting result is that although with different properties, both polymer and composite particles were able to form a calcium phosphate layer at their surface, which is a clear indication of their bioactivity. The cytotoxicity and the ability to support cell attachment and growth of the developed materials were also studied, and both polymer and composite materials were shown to be non-cytotoxic. Preliminary results show that both types of materials were found to allow rat bone marrow cells to attach and to proliferate on their surface and to express osteogenic markers, such as alkaline phosphatase and osteopontin. The obtained results indicate that the developed carriers might be used as substrates for cell culture in vitro, in order to form constructs that might be used as a part of a tissue engineering strategy

    Production of electroactive filaments by coextrusion

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    The development of new products for i-textiles (interactive textiles) or e-textiles (electronic textiles) applications shows a significant growth in the most recent years due to their huge potential. Although much scientific work has been published in the last years, actual practical applications are still limited. This is due, on one hand, to unsatisfactory state of development of the technology and, on the other, to difficulties on the integration of technologies and methods of the textile and electronic areas. Products for e/i-textiles very often involve the use of sensors, preferably in the form of films, filaments or fibres, due to the inherent easy insertion in the product. For this purpose, electroactive filaments, that benefit from the piezoelectric properties of poly(vinylidene fluoride), PVDF, can be an interesting choice. There aresome works published in the literature related to the development of films with piezoelectric properties [1], that employ PVDF as the electroactive material. However, despite its importance, the manufacture methodologies employed are very difficult to use in industrial scale production. In this work a novel methodology for the production of electroactive filaments, by coextrusion of PVDF and an electrical conductive polymer composite, is proposed and tested. The developed methodology involves a conventional coextrusion line, and can be easily scaled up for industrial massive production. It is shown that The PVDF filament with a conductive PP/carbon black composite core crystallizes in the crystalline phase related just to the temperatures and stretch ratio conditions, independently of the existence of the conductive core: for 80ºC the material crystallizes in the -phase and undergoes increasing to phase transformation for increasing stretch ratios from 1 to 5.FCT- Portuguese Foundation for Science and Technology through the projects PTDC/CTM/69316/2006, NANO/NMed-SD/0156/2007 and PTDC/CTM/108801/2008 and FEDER via FCT, Fundação para a Ciência e Tecnologia, under the POCI 2010 and Pluriannual programs. A.F., P.C. and V. S. thank the FCT grants SFRH/BD/69796/2010, SFRH/BD/64267/2009 and SFRH/BPD/63148/200

    Towards automated test and validation of SIP solutions

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    IP networks are currently the major communication infrastructure used by an increasing number of applications and heterogeneous services, including voice services. In this context, the Session Initiation Protocol (SIP) is a signaling protocol widely used for controlling multimedia communication sessions such as voice or video calls over IP networks, thus performing vital functions in an extensive set of public and enter- prise solutions. However, the SIP protocol dissemination also entails some challenges, such as the complexity associated with the testing/validation processes of IMS/SIP networks. As a consequence, manual IMS/SIP testing solutions are inherently costly and time consuming tasks, being crucial to develop automated approaches in this specific area. In this perspective, this article presents an experimental approach for automated testing/validation of SIP scenarios in IMS networks. For that purpose, an automation framework is proposed allowing to replicate the configuration of SIP equipment from the pro- duction network and submit such equipment to a battery of tests in the testing network. The proposed solution allows to drastically reduce the test and validation times when compared with traditional manual approaches, also allowing to enhance testing reliability and coverage. The automation framework comprises of some freely available tools which are conveniently integrated with other specific modules implemented within the context of this work. In order to illustrate the advantages of the proposed automated framework, a real case study taken from a PT Inovação customer is presented comparing the time required to perform a manual SIP testing approach with the one time required when using the proposed auto- mated framework. The presented results clearly corroborate the advantages of using the presented framework.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: PEstOE/EEI/UI0319/2014. This research work was developed within the collaboration of PT Inovação (http://www.ptinovacao.pt/ en/)
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