Photo-detectors integrated with resonant tunneling diodes

We report on photo-detectors consisting of an optical waveguide that incorporates a resonant tunneling diode (RTD). Operating at wavelengths around 1.55 μm in the optical communications C band we achieve maximum sensitivities of around 0.29 A/W which is dependent on the bias voltage. This is due to the nature of RTD nonlinear current-voltage characteristic that has a negative differential resistance (NDR) region. The resonant tunneling diode photo-detector (RTD-PD) can be operated in either non-oscillating or oscillating regimes depending on the bias voltage quiescent point. The oscillating regime is apparent when the RTD-PD is biased in the NDR region giving rise to electrical gain and microwave self-sustained oscillations Taking advantage of the RTD’s NDR distinctive characteristics, we demonstrate efficient detection of gigahertz (GHz) modulated optical carriers and optical control of a RTD GHz oscillator. RTD-PD based devices can have applications in generation and optical control of GHz low-phase noise oscillators, clock recovery systems, and fiber optic enabled radio frequency communication systems.info:eu-repo/semantics/publishedVersio

Physical and technical performances are not associated with tactical prominence in U14 soccer matches

The aim of this study was to analyse the association between physical/technical variables and the tactical prominence variables in U14 soccer matches. Twenty-two young amateur soccer players (13.5 0.5 years old, 5.4 0.5 years of practice, 163.3 9.8 cm in body height) from two teams of the Portuguese regional league volunteered for the study. Our results showed positive and moderate correlation between dribbling test and betweenness centrality (r = 0.324; p = 0.142), and negative moderate correlation between %fatigue index and betweenness centrality (r = −0.390; p = 0.073). Physical and technical variables had no statistical differences among tactical positions. Nevertheless, when tactical prominence of players from four tactical positions were compared, significant differences were found in terms of degree prestige (p = 0.001) and degree centrality (p = 0.002). This pilot study did not find strong correlations between physical/technical levels and tactical prominence in soccer matches.info:eu-repo/semantics/publishedVersio

Fecal occult blood and fecal calprotectin as point-of-care markers of intestinal morbidity in Ugandan children with Schistosoma mansoni infection.

BACKGROUND: Calprotectin is a calcium-binding cytoplasmic protein found in neutrophils and increasingly used as a marker of bowel inflammation. Fecal occult blood (FOB) is also a dependable indicator of bowel morbidity. The objective of our study was to determine the applicability of these tests as surrogate markers of Schistosoma mansoni intestinal morbidity before and after treatment with praziquantel (PZQ). METHODS: 216 children (ages 3-9 years old) from Buliisa District in Lake Albert, Uganda were examined and treated with PZQ at baseline in October 2012 with 211 of them re-examined 24 days later for S. mansoni and other soil transmitted helminths (STH). POC calprotectin and FOB assays were performed at both time points on a subset of children. Associations between the test results and infection were analysed by logistic regression. RESULTS: Fecal calprotectin concentrations of 150-300 µg/g were associated with S. mansoni egg patent infection both at baseline and follow up (OR: 12.5 P = 0.05; OR: 6.8 P = 0.02). FOB had a very strong association with baseline anemia (OR: 9.2 P = 0.03) and medium and high egg intensity schistosomiasis at follow up (OR: 6.6 P = 0.03; OR: 51.3 P = 0.003). Both tests were strongly associated with heavy intensity S. mansoni infections. There was a significant decrease in FOB and calprotectin test positivity after PZQ treatment in those children who had egg patent schistosomiasis at baseline. CONCLUSIONS: Both FOB and calprotectin rapid assays were found to correlate positively and strongly with egg patent S. mansoni infection with a positive ameloriation response after PZQ treatment indicative of short term reversion of morbidity. Both tests were appropriate for use in the field with excellent operational performance and reliability. Due to its lower-cost which makes its scale-up of use affordable, FOB could be immediately adopted as a monitoring tool for PC campaigns for efficacy evaluation before and after treatment

Characterization of Active Sites on Carbon Catalysts

A method based on the deconvolution of TPD spectra is proposed for the characterization of surface oxygen groups, which can act as the active sites on carbon catalysts. The method, which was previously used to characterize activated carbons oxidized in the gas phase, has been extended and applied to other materials, carbons oxidized in the liquid phase. It is shown that this method fits quite well the TPD experimental data of the original activated carbon as well as the gas-phase and liquid-phase oxidized materials and is suitable to estimate the amounts of each type of oxygen surface groups.info:eu-repo/semantics/publishedVersio

Optimization of clavulanic acid production by Streptomyces daufpe 3060 by response surface methodology

Clavulanic acid is a β-lactam antibiotic which has a potent β-lactamase inhibiting activity. In order to optimize its production by the new isolate Streptomyces DAUFPE 3060, the influence of two independent variables, temperature and soybean flour concentration, on clavulanic acid and biomass concentrations was investigated in 250 mL-Erlenmeyers according to a 2² central composite design. To this purpose, temperature and soybean flour (SF) concentration were varied in the ranges 26-34°C and 10-50 g/L, respectively, and the results evaluated utilizing the Response Surface Methodology. The experimental maximum production of clavulanic acid (629 mg/L) was obtained at 32°C and 40 g/L SF after 48 h, while the maximum biomass concentration (3.9 g/L) at 30°C and 50 g/L soybean flour, respectively. These values are satisfactorily close to those (640 mg/L and 3.75 g/L, respectively) predicted by the model, thereby demonstrating the validity of the mathematical approach adopted in this study.Brazilian Research Funding InstitutionsCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Delay dynamics of neuromorphic optoelectronic nanoscale resonators: Perspectives and applications

With the recent exponential growth of applications using artificial intelligence (AI), the development of efficient and ultrafast brain-like (neuromorphic) systems is crucial for future information and communication technologies. While the implementation of AI systems using computer algorithms of neural networks is emerging rapidly, scientists are just taking the very first steps in the development of the hardware elements of an artificial brain, specifically neuromorphic microchips. In this review article, we present the current state of the art of neuromorphic photonic circuits based on solid-state optoelectronic oscillators formed by nanoscale double barrier quantum well resonant tunneling diodes. We address, both experimentally and theoretically, the key dynamic properties of recently developed artificial solid-state neuron microchips with delayed perturbations and describe their role in the study of neural activity and regenerative memory. This review covers our recent research work on excitable and delay dynamic characteristics of both single and autaptic (delayed) artificial neurons including all-or-none response, spike-based data encoding, storage, signal regeneration and signal healing. Furthermore, the neural responses of these neuromorphic microchips display all the signatures of extended spatio-temporal localized structures (LSs) of light, which are reviewed here in detail. By taking advantage of the dissipative nature of LSs, we demonstrate potential applications in optical data reconfiguration and clock and timing at high-speeds and with short transients. The results reviewed in this article are a key enabler for the development of high-performance optoelectronic devices in future high-speed brain-inspired optical memories and neuromorphic computing. (C) 2017 Author(s).Fundacao para a Ciencia e a Tecnologia (FCT) [UID/Multi/00631/2013]European Structural and Investment Funds (FEEI) through the Competitiveness and Internationalization Operational Program - COMPETE 2020National Funds through FCT [ALG-01-0145-FEDER-016432/POCI-01-0145-FEDER-016432]European Commission under the project iBROW [645369]project COMBINA [TEC2015-65212-C3-3-PAEI/FEDER UE]Ramon y Cajal fellowshipinfo:eu-repo/semantics/publishedVersio

Policy-based Adaptive Routing in Autonomous WSNs

Abstract. Wireless sensor networks (WSNs) are employed in different domains and applications. The resource constraint on such networks, many times composed of hundreds to thousands of devices, and the requirement of autonomous operation become their management a challenging task. This work applies policies, a well-known approach in network management, in the core task of routing in autonomous WSNs. Policies are used to establish rules to take dynamic actions on the network according to its state. Our scheme offers a high-level and flexible way to realize management tasks related to routing in WSNs, which can be defined in a progressive way as knowledge from the environment is acquired or application requirements change. Case studies employing a policy-based adaptive hybrid solution allows the autonomous selection of the best routing strategy in view of network conditions and application requirements. Simulation results show the benefits and resource savings offered by the use of policies for adaptive routing in WSNs

Retinitis induction by human cytomegalovirus in imunossupressed rabbits

The search for new therapies to the HCMV retinitis made researchers look for an animal model for this infection. In anterior study we didn’t get a good level of imunossupression in rabbits with Azathiprina and Prednisona. In this way, we opt for use the Cyclophosphamide in five rabbits of New Zealand race, in which were injected HCMV in vitreous of both eyes, in different stages of imunossupression protocol. The observation period was 112 days, observing sistemics alterations (weight, blood count) and ocular alterations (trough binocular ophthalmoscopy and retinography ). After the animals sacrifice, it was researched HCMV antigens in vitreous and retina. It was found important weight loss, blood count not compatible with the imunossupression signs, retinians lesions and vitreous alterations not specifics (exsudate and vitreits with spontaneous involution ). It wasn’t detected HCMV antigens in vitreous and retina inprints from the sacrificed rabbits. In this way, it was concluded that also with this new imunossupression scheme, the HCMV causes not specific intra-ocular inflamation. Therefore, the HCMV inoculation in rabbits doesn’t determine an experimental model to HCMV retinitis.A procura por novos esquemas terapêuticos para a retinite por HCMV levou pesquisadores à busca de um modelo animal para o estudo desta infecção. Em estudo anterior, não conseguimos nível adequado de imunossupressão com associação de Azathioprina e Prednisona em coelhos. Assim, optamos por utilizar a Ciclofosfamida em cinco coelhos da raça New Zealand, e injetamos HCMV no vítreo de ambos os olhos de cada um deles, em diferentes etapas do protocolo de imunossupressão. O período de seguimento foi de até 112 dias, avaliando-se alterações sistêmicas (peso, hemograma) e alterações oculares (através de oftalmoscopia binocular indireta e retinografia). Após o sacrifício dos animais, pesquisaram-se antígenos de HCMV em vítreo e retina. Encontrou-se importante perda de peso, hemograma não compatível com os sinais de imunossupressão, lesões retinianas e alterações vítreas inespecíficas (exsudatos e vitreíte com involução espontânea). Não foram detectados antígenos de HCMV nos Inprints de retinas e vítreos dos coelhos sacrificados. Desse modo, concluiu-se que, também com esse novo esquema de imunossupressão, o HCMV causa inflamação intra-ocular inespecífica. Portanto, a inoculação do HCMV, em coelhos, não determina modelo experimental para a retinite pelo CMV

Porphyrin–nanodiamond hybrid materials—active, stable and reusable cyclohexene oxidation catalysts

funded by FCT-Foundation for Science and Technology, I.P., under projects UIDB/00313/2020; PTDC/QUI-OUT/27996/2017 (DUALPI); POCI-01-0145-FEDER-027996; POCI-01-0145-FEDER-016387; UIDB/50006/2020 (Associate Laboratory for Green Chemistry-LAQV); MATIS (CENTRO-010145-FEDER-00014); Base Funding-UIDB/50020/2020 of the Associate Laboratory LSRE-LCM-funded by national funds through FCT/MCTES (PIDDAC); and 5625-DRI-DAAD-2020/21. SACC also acknowledges FCT Investigador FCT program (IF/01381/2013/CP1160/CT0007) and Scientific Employment Stimulus -Institutional Call (CEECINST/00102/2018). The authors also thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) for CEPOF 2013/07276-1, and INCT "Basic Optics and Applied to Life Sciences" (FAPESP 2014/50857-8, CNPq 465360/2014-9). A.R.L. Caires acknowledges CAPES-PrInt funding program (grant number 88887.353061/2019-00 and 88881.311921/2018-01). J.G.B. thanks the Dutch Research Council (NWO) for funding as a part of the Open Technology Programme (project number 16361). L.D. Dias thanks FAPESP for the Post-doc grant 2019/13569-8. F.M.S.R. thanks FCT for the PhD grant (PD/BD/114340/2016).The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, covalently linked hybrid porphyrin–nanodiamonds were prepared via ipso nitro substitution reaction and characterized by X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, infrared spectroscopy (IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The amine-functionalized nanodiamonds (ND@NH2 ) and 2-nitro-5,10,15,20-tetra(4-trifluoromethylphenyl)porphyrin covalently linked to nanodiamonds (ND@βNH-TPPpCF3 ) were tested using Allium cepa as a plant model, and showed neither phytotoxicity nor cytotoxicity. The hybrid nanodiamond–copper(II)–porphyrin material ND@βNH-TPPpCF3-Cu(II) was also evaluated as a reusable catalyst in cyclohexene allylic oxidation, and displayed a remarkable turnover number (TON) value of ≈265,000, using O2 as green oxidant, in the total absence of sacrificial additives, which is the highest activity ever reported for said allylic oxidation. Additionally, ND@βNH-TPPpCF3-Cu(II) could be easily separated from the reaction mixture by centrifugation, and reused in three consecutive catalytic cycles without major loss of activity.publishersversionpublishe