Optical doping and damage formation in AIN by Eu implantation

AlN films grown on sapphire were implanted with 300 keV Eu ions to fluences from 3×1014 to 1.4×1017 atoms/cm2 in two different geometries: “channeled” along the c-axis and “random” with a 10° angle between the ion beam and the surface normal. A detailed study of implantation damage accumulation is presented. Strong ion channeling effects are observed leading to significantly decreased damage levels for the channeled implantation within the entire fluence range. For random implantation, a buried amorphous layer is formed at the highest fluences. Red Eu-related photoluminescence at room temperature is observed in all samples with highest intensities for low damage samples (low fluence and channeled implantation) after annealing. Implantation damage, once formed, is shown to be stable up to very high temperatures.FCT - POCI/FIS/57550/2004FCT - PTDC/FIS/66262/2006FCT - PTDC/CTM/100756/200

Parotidite Como Primeira Manifestação de Infecção por VIH

Introdução: Actualmente, a maioria dos casos pediátricos de infecção por VIH é devida a transmissão materna do vírus. Na ausência de medidas de profilaxia, verificam se taxas de transmissão vertical do VIH-1 entre 15-25% na Europa Ocidental e Estados Unidos, 65% dos casos no peri-parto, 23% in útero e 12% no período pós-natal durante a amamentação. Caso clínico: Criança de 9 anos, sexo feminino, que recorre à urgência por febre, anorexia e tumefacção cervical com 2 dias de evolução. Dos antecedentes pessoais há a destacar: gravidez não vigiada, parto eutócico de termo, aleitamento materno até aos 3 anos e atraso do desenvolvimento estaturo-ponderal. Antecedentes patológicos de parotidite bilateral aos 5 anos e múltiplas cáries dentárias. À observação apresentava-se febril, emagrecida (peso < P5 e estatura no P5), com tumefacção cervical e retroauricular direitas, e aumento de volume das glândulas parótidas. Sem hepatoesplenomegalia e sem adenopatias palpáveis nas restantes cadeias ganglionares periféricas. Analíticamente, VS de 90 mm/h, sem outras alterações relevantes. Ecografia cervical mostrou adenofleimão e alterações compatíveis com parotidite. Internada com a hipótese diagnóstica de adenofleimão cervical e medicada com penicilina e clindamicina endovenosas (ev). Realizou serologias para VIH, com positividade para VIH tipo 1, confirmado por Western Blot. Contagem de linfócitos T CD4+ de 240 células/mm3. Carga viral de 3,82 x 103 cópias de RNA/mL. Genótipo HLA-B*5701 negativo. Confirmada infecção VIH 1 materna por Western Blot. Diagnóstico prévio de infecção VIH no período neonatal ocultado pela mãe. Restantes serologias negativas, assim como a pesquisa de BK no suco gástrico e o estudo do lavado bronco-alveolar. Ao 17º dia de internamento foi realizada punção do adenofleimão e alterada a antibioticoterapia para flucloxacilina ev (7 dias de terapêutica). Pesquisa de micobactérias e fungos no pús drenado negativa. Durante o internamento manteve-se clinicamente estável, iniciando profilaxia para Pneumocystis jirovecii com cotrimoxazol, e terapêutica anti-retroviral (Lamivudina, Abacavir, Lopinavir/Ritonavir), com melhoria clínica, virulógica e imunológica. Conclusões: Este caso ilustra um exemplo de transmissão vertical do VIH-1 caracterizado por uma evolução crónica, cuja apresentação cursou com parotidite, um dos sinais indicadores de infecção VIH

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

Variação da alogamia em população recorrente para o desenvolvimento de genitores de híbridos em arroz.

O objetivo deste trabalho foi verificar tendências na variação em alogamia, de uma população desenvolvida para a criação de linhagens genitoras de híbridos, do Programa Arroz Híbrido Embrapa-Cirad

Comparative evolutionary analysis of IL6 in lagomorphs

Background and aims: Interleukin 6 (IL6), also known as interferon beta 2, is a class-I helical cytokine with a broad spectrum of biological activities in humoral and cellular defense. This class of cytokines has a gene structure conserved throughout vertebrates, with five coding exons. IL6 is involved in the immune response against rabbit hemorrhagic disease virus that causes a highly fatal disease in the European rabbit. Previously, IL6 from European rabbit samples belonging to the subspecies Oryctolagus cuniculus cuniculus, was shown to differ from the other mammals by extending for further 27 amino acids. This difference results from a mutation in the typical stop codon into a glutamate encoding codon. However, in other leporids (Sylvilagus spp. and Lepus spp.) that diverged from European rabbit approximately 12 million years ago this mutation was also not present. The purpose of this study was to confirm the mutation of the stop codon in other lagomorph specimens: Oryctolagus cuniculus algirus, Brachylagus idahoensis, Sylvilagus bachmanii, Lepus europaeus and Ochotona princeps. Methods: The IL6 gene was PCR-amplified and sequenced for the five lagomorph species. The obtained sequences were translated and compared with other mammalian IL6 sequences retrieved from public databases (GenBank, Ensembl and Uniprot). A maximum-likelihood (ML) tree was inferred in MEGA5 with the following options: HKY+G model, 500 bootstrap replicates and partial deletion to gaps/missing data treatment. Results: We confirmed the presence of the mutated stop codon in both O. c. cuniculus and O. c. algirus. In agreement with previous reports, we found that the stop codon is not mutated in S. bachmanii and L. europaeus. We further extended this observation to the leporid B. idahoensis and ochotonid O. princeps. In rabbits, sequence translation of IL6 continues into the exonic sequence and stops in the next STOP codon (81 nucleotides downstream). Typically, the IL6 protein has five cysteine residues that might be important to establish disulfide bonds. In rabbit, the 27 amino acid extension has four more cysteine residues. The inferred phylogeny for the IL6 gene is in agreement with what has been accepted for the mammals and lagomorphs.Conclusions: Our results indicate that in the ancestral of the Oryctolagusgenus, (approximately 2 million years ago), a single mutation at exon 5 occurred that made IL6 longer than for the other mammals. Biological implications of this extension remain to be assessed but the occurrence of the 4 extra cysteine residues might suggest some functional relevance

Research and the teaching in Design and Music

Um livro com diversas perspetivas sobre projetos e processos de investigação nas áreas do design e da música. São 50 escritos por autores de diferentes países, que contribuem para uma perspectiva ampla nestes domínios.info:eu-repo/semantics/publishedVersio