Functionalizing self-assembled GaN quantum dot superlattices by Eu-implantation

Self-assembled GaN quantum dots (QDs) stacked in superlattices (SL) with AlN spacer layers were implanted with Europium ions to fluences of 1013, 1014, and 1015 cm−2. The damage level introduced in the QDs by the implantation stays well below that of thick GaN epilayers. For the lowest fluence, the structural properties remain unchanged after implantation and annealing while for higher fluences the implantation damage causes an expansion of the SL in the [0001] direction which increases with implantation fluence and is only partly reversed after thermal annealing at 1000 °C. Nevertheless, in all cases, the SL quality remains very good after implantation and annealing with Eu ions incorporated preferentially into near-substitutional cation sites. Eu3+ optical activation is achieved after annealing in all samples. In the sample implanted with the lowest fluence, the Eu3+ emission arises mainly from Eu incorporated inside the QDs while for the higher fluences only the emission from Eu inside the AlN-buffer, capping, and spacer layers is observed. © 2010 American Institute of PhysicsFCT-PTDC/CTM/100756/2008program PESSOA EGIDE/GRICESFCT-SFRH/BD/45774/2008FCT-SFRH/BD/44635/200

Estudo sobre a influência da compactação na resistência do betão à carbonatação

Trabalho apresentado em 6º Congresso Luso-Moçambicano de Engenharia, 2011 Maputo, MoçambiqueN/

Influence of the sodium/proton replacement on the structural, morphological and photocatalytic properties of titanate nanotubes

Titanate nanotubes (TNT) with different sodium contents have been synthesised using a hydrothermal approach and a swift and highly controllable post-washing processes. The influence of the sodium/proton replacement on the structural and morphological characteristics of the prepared materials was analysed. Different optical behaviour was observed depending on the Na+/H+ samples' content. A band gap energy of 3.27\pm0.03 eV was estimated for the material with higher sodium content while a value of 2.81\pm0.02 eV was inferred for the most protonated material, which therefore exhibits an absorption edge in the near visible region. The point of zero charge of the materials was determined and the influence of the sodium content on the adsorption of both cationic and anionic organic dyes was studied. The photocatalytic performance of the TNT samples was evaluated in the rhodamine 6G degradation process. Best photodegradation results were obtained when using the most protonated material as catalyst, although this material has shown the lowest R6G adsorption capability.Comment: 22 pages, 8 figures, accepted for publication in Journal of Photochemistry and Photobiology A: Chemistr

Development system for FPGA-based digital circuits

“Copyright © [1999] IEEE. Reprinted from 7th Annual IEEE Symposium on Field-Programmable Custom Computing Machines ISBN:0-7695-0375-6. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”The paper discusses some new hardware and software tools that can be used for the design of virtual circuits based on dynamically reconfigurable FPGAs. With the aid of these tools we can implement a system that requires some hardware resources Rc, on available hardware that has resources Rh, where Rc>Rh. The main idea of the approach supported by these tools is the rational combination of FPGA capabilities with some proposed methods for producing a modifiable specification, together with a novel technique for architectural and logic synthesis, which has been incorporated into the new design environment

Multicentric Genome-Wide Association Study for Primary Spontaneous Pneumothorax

Despite elevated incidence and recurrence rates for Primary Spontaneous Pneumothorax (PSP), little is known about its etiology, and the genetics of idiopathic PSP remains unexplored. To identify genetic variants contributing to sporadic PSP risk, we conducted the first PSP genome-wide association study. Two replicate pools of 92 Portuguese PSP cases and of 129 age- and sex-matched controls were allelotyped in triplicate on the Affymetrix Human SNP Array 6.0 arrays. Markers passing quality control were ranked by relative allele score difference between cases and controls (|RASdiff|), by a novel cluster method and by a combined Z-test. 101 single nucleotide polymorphisms (SNPs) were selected using these three approaches for technical validation by individual genotyping in the discovery dataset. 87 out of 94 successfully tested SNPs were nominally associated in the discovery dataset. Replication of the 87 technically validated SNPs was then carried out in an independent replication dataset of 100 Portuguese cases and 425 controls. The intergenic rs4733649 SNP in chromosome 8 (between LINC00824 and LINC00977) was associated with PSP in the discovery (P = 4.07E-03, ORC[95% CI] = 1.88[1.22-2.89]), replication (P = 1.50E-02, ORC[95% CI] = 1.50[1.08-2.09]) and combined datasets (P = 8.61E-05, ORC[95% CI] = 1.65[1.29-2.13]). This study identified for the first time one genetic risk factor for sporadic PSP, but future studies are warranted to further confirm this finding in other populations and uncover its functional role in PSP pathogenesis

Synthesis of titanate nanostructures using amorphous precursor material and their adsorption/photocatalytic properties

This paper reports on a new and swift hydrothermal chemical route to prepare titanate nanostructures (TNS) avoiding the use of crystalline TiO2 as starting material. The synthesis approach uses a commercial solution of TiCl3 as titanium source to prepare an amorphous precursor, circumventing the use of hazardous chemical compounds. The influence of the reaction temperature and dwell autoclave time on the structure and morphology of the synthesised materials was studied. Homogeneous titanate nanotubes with a high length/diameter aspect ratio were synthesised at 160^{\circ}C and 24 h. A band gap of 3.06\pm0.03 eV was determined for the TNS samples prepared in these experimental conditions. This value is red shifted by 0.14 eV compared to the band gap value usually reported for the TiO2 anatase. Moreover, such samples show better adsorption capacity and photocatalytic performance on the dye rhodamine 6G (R6G) photodegradation process than TiO2 nanoparticles. A 98% reduction of the R6G concentration was achieved after 45 minutes of irradiation of a 10 ppm dye aqueous solution and 1 g/L of TNS catalyst.Comment: 29 pages, 10 figures, accepted for publication in Journal of Materials Scienc

Primary Aldosteronism: results from the first Portuguese multicentre study by the adrenal tumour study group

Introduction: Primary Aldosteronism (PA) is the most prevalent cause of secondary hypertension. Nevertheless, there is no portuguese multicenter study characterizing PA patients. Aims: To characterize the clinical presentation, diagnostic workup, treatment and follow-up of patients with confirmed PA. Methods: Retrospective multicenter study of PA patients followed in 9 portuguese hospitals. Results: Sixty-three cases were selected with a mean age of diagnosis of 52.1 ± 13.1 years, 9.9 years after the diagnosis of hypertension. At presentation, 37 cases (60.7%) had hypertension, 11 (22.9%) had resistant hypertension and 20 (32.8%) of patients had hipokalemia (mean 3.2 mmol/L). Baseline laboratory showed a mean serum aldosterone of 33.4ng/dL, plasmatic renin activity (PRA) of 0.2ng/mL/h with an aldosterone/PRA ratio of 97.1. Confirmatory testing was performed with saline infusion in 55 patients (positive in 84.4%) and captopril test in 14 (positive in 85.7%). Imaging showed adenomas in 55 cases, hyperplasia in 2 and bilateral cases in 8. Arterial venous sampling (AVS) was performed in 9 patients (14,5%) and was conclusive in 1. Iodocholesterol scintigraphy was done in 14 cases (22%) with unilateral fixation in 9 and no fixation in 4. Patients were treated with laparoscopic adrenalectomy in 28 cases (58.3%) and mineralocorticoid receptor antagonists in 20 cases (41.7%). The surgical treated group had less duration of hypertension (8 versus 14 years, p = 0.002), higher prevalence of anti-hypertensive drugs at presentation (100 versus 75% p = 0.009) and bigger tumour size (1.8 versus 1.5 cm, p = 0.022). During follow-up there was a trend towards a greater proportion of patients with no hypertension improvement in the medical treatment group (29.4% versus 7.4%, p = 0.089). Conclusion: This is the first Portuguese PA multicenter study. It suggests that PA remains an under- -diagnosed condition with a significant delay in diagnosis. Surgical treated patients had a more aggressive disease and showed a trend towards better hypertension control

Endo-β-1,3-glucanase (GH16 Family) from Trichoderma harzianum Participates in Cell Wall Biogenesis but Is Not Essential for Antagonism Against Plant Pathogens

This is the published version. Available on open access from MDPI via the DOI in this recordTrichoderma species are known for their ability to produce lytic enzymes, such as exoglucanases, endoglucanases, chitinases, and proteases, which play important roles in cell wall degradation of phytopathogens. β-glucanases play crucial roles in the morphogenetic-morphological process during the development and differentiation processes in Trichoderma species, which have β-glucans as the primary components of their cell walls. Despite the importance of glucanases in the mycoparasitism of Trichoderma spp., only a few functional analysis studies have been conducted on glucanases. In the present study, we used a functional genomics approach to investigate the functional role of the gluc31 gene, which encodes an endo-β-1,3-glucanase belonging to the GH16 family in Trichoderma harzianum ALL42. We demonstrated that the absence of the gluc31 gene did not affect the in vivo mycoparasitism ability of mutant T. harzianum ALL42; however, gluc31 evidently influenced cell wall organization. Polymer measurements and fluorescence microscopy analyses indicated that the lack of the gluc31 gene induced a compensatory response by increasing the production of chitin and glucan polymers on the cell walls of the mutant hyphae. The mutant strain became more resistant to the fungicide benomyl compared to the parental strain. Furthermore, qRT-PCR analysis showed that the absence of gluc31 in T. harzianum resulted in the differential expression of other glycosyl hydrolases belonging to the GH16 family, because of functional redundancy among the glucanases.CNPq Rede Pró-Centro OesteState of São Paulo Research Foundation (FAPESP

A spectroscopic and proper motion search of Sloan Digital Sky Survey : red subdwarfs in binary systems

Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan Digital Sky Survey spectroscopy. We present here discoveries from this search, as well as highlight several additional objects of interest. We find 30 red subdwarfs in wide binary systems including: two with spectral type of esdM5.5, 6 companions to white dwarfs and 3 carbon-enhanced red subdwarfs with normal red subdwarf companions. 15 red subdwarfs in our sample are partially resolved close binary systems. With this binary sample, we estimate the low limit of the red subdwarf binary fraction of similar to 10 per cent. We find that the binary fraction goes down with decreasing masses and metallicities of red subdwarfs. A spectroscopic esdK7 subdwarf + white dwarf binary candidate is also reported. 30 new M subdwarfs have spectral type of >= M6 in our sample. We also derive relationships between spectral types and absolute magnitudes in the optical and near-infrared for M and L subdwarfs, and we present an M subdwarf sample with measured U, V, W space velocities.Peer reviewe

Pesquisa e percepção pública sobre biossegurança de OGM: subsídios para decisões estratégicas na America Latina.

O projeto LAC-Biosafety é um consórcio entre Brasil, Colômbia, Costa Rica e Peru, sob a coordenação do Centro Internacional de Agricultura Tropical. Suas atividades de pesquisa visam complementar informações técnicas de biossegurança ambiental para as culturas de algodão, arroz, batata, mandioca e milho, buscando harmonização de propostas de pesquisa em nível regional. Ao mesmo tempo busca subsidiar o conhecimento do impacto socioeconômico de algumas dessas culturas. Merece destaque a maneira inovadora de detectar a percepção pública sobre o tema para caracterizar e atender às necessidades de comunicação adequadas com os consumidores. Esse componente do projeto vem ao encontro de expectativas regionais e nacionais, bem como dos valores e diretrizes estratégicas da Embrapa quando propõe o aprimoramento dos canais de diálogo com seus públicos alvo sobre a biossegurança de culturas agrícolas de vulto socioeconômico. As informações técnicas geradas preencherão vazios de informação e apoiarão órgãos nacionais competentes na tomada de decisão. A Embrapa será o agente facilitador do acesso à informação científica e facilitador do diálogo na sociedade. Essas ações do projeto também atendem às prioridades recém estabelecidas na conferência da FAO (Guadalajara, março 2010) sobre biotecnologias na agricultura de países em desenvolvimento. Futuramente espera-se que o projeto possa se consolidar como elemento aglutinador dos pesquisadores e comunicadores da Embrapa envolvidos nesta área.Disponível em: Acesso em: 21 fev. 2011