Nuevo ensayo para la determinación de frecuencias fundamentales longitudinales, transversales y torsionales en probetas de hormigón

For twenty-five years The ASTM method used to determine reductions in concrete durability after freeze-thaw cycling has been C215-60. In this test the fundamental frequencies of a concrete specimen are compared. This test is time consuming, noisy and often inaccurate. In this paper a new method is proposed for measuring the fundamental frequencies of concrete to a single tap via a Fast Fourier Transform. The new test is faster, simpler and more accurate.El método usado por la ASTM desde hace 25 años para la determinación de la durabilidad del hormigón después de sufrir ciclos hielo/deshielo ha sido el C215-60. En este ensayo se comparan las frecuencias fundamentales de una probeta de hormigón. Este ensayo es ruidoso, lleva bastante tiempo y es bastante impreciso. En este trabajo se pone un nuevo método para medias frecuencias fundamentales en el hormigón por simple golpe mediante la TRANSFORMADA RÁPIDA de FOURIER. El nuevo método es más rápido, más simple y más preciso

CTNNB1, AXIN1 and APC expression analysis of different medulloblastoma variants

OBJECTIVES: We investigated four components of the Wnt signaling pathway in medulloblastomas. Medulloblastoma is the most common type of malignant pediatric brain tumor, and the Wnt signaling pathway has been shown to be activated in this type of tumor. METHODS: Sixty-one medulloblastoma cases were analyzed for β-catenin gene (CTNNB1) mutations, β-catenin protein expression via immunostaining and Wnt signaling pathway-related gene expression. All data were correlated with histological subtypes and patient clinical information. RESULTS: CTNNB1 sequencing analysis revealed that 11 out of 61 medulloblastomas harbored missense mutations in residues 32, 33, 34 and 37, which are located in exon 3. These mutations alter the glycogen synthase kinase-3β phosphorylation sites, which participate in β-catenin degradation. No significant differences were observed between mutation status and histological medulloblastoma type, patient age and overall or progression-free survival times. Nuclear β-catenin accumulation, which was observed in 27.9% of the cases, was not associated with the histological type, CTNNB1 mutation status or tumor cell dissemination. The relative expression levels of genes that code for proteins involved in the Wnt signaling pathway (CTNNB1, APC, AXIN1 and WNT1) were also analyzed, but no significant correlations were found. In addition, large-cell variant medulloblastomas presented lower relative CTNNB1 expression as compared to the other tumor variants. CONCLUSIONS: A small subset of medulloblastomas carry CTNNB1 mutations with consequent nuclear accumulation of β-catenin. The Wnt signaling pathway plays a role in classic, desmoplastic and extensive nodularity medulloblastoma variants but not in large-cell medulloblastomas

Ataxia de Friedreich: estudo clínico e molecular de 25 pacientes

INTRODUCTION: Friedreich's ataxia is a neurodegenerative disorder whose clinical diagnostic criteria for typical cases basically include: a) early age of onset (< 20 or 25 years), b) autosomal recessive inheritance, c) progressive ataxia of limbs and gait, and d) absence of lower limb tendon reflexes. METHODS: We studied the frequency and the size of expanded GAA and their influence on neurologic findings, age at onset, and disease progression in 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia - 19 typical and 6 atypical - using a long-range PCR test. RESULTS: Abnormalities in cerebellar signs, in electrocardiography, and pes cavus occurred more frequently in typical cases; however, plantar response and speech were more frequently normal in this group when the both typical and atypical cases were compared. Homozygous GAA expansion repeats were detected in 17 cases (68%) - all typical cases. In 8 patients (32%) (6 atypical and 2 typical), no expansion was observed, ruling out the diagnosis of Friedreich's ataxia. In cases with GAA expansions, foot deformity, cardiac abnormalities, and some neurologic findings occurred more frequently; however, abnormalities in cranial nerves and in tomographic findings were detected less frequently than in patients without GAA expansions. DISCUSSION: Molecular analysis was imperative for the diagnosis of Friedreich's ataxia, not only for typical cases but also for atypical ones. There was no genotype-phenotype correlation. Diagnosis based only on clinical findings is limited; however, it aids in better screening for suspected cases that should be tested. Evaluation for vitamin E deficiency is recommended, especially in cases without GAA expansion.INTRODUÇÃO: A ataxia de Friedreich é uma doença neurodegenerativa e os critérios clínicos diagnósticos para os casos típicos incluem: a) idade de início precoce (< 20 ou 25 anos); b) herança autossômica recessiva; c) ataxia progressiva; e d) abolição dos reflexos tendinosos profundos. MÉTODOS: Estudou-se a freqüência e o tamanho das expansões GAA e a sua influência nos achados neurológicos, idade de início e progressão da doença, em 25 pacientes brasileiros com diagnóstico clínico de ataxia de Friedreich - 19 típicos e 6 atípicos, por PCR. RESULTADOS: Anormalidades sugestivas de comprometimento cerebelar, no ECG e a presença de pés cavos ocorreram com maior freqüência nos casos típicos; contudo, a resposta plantar e a fala mostraram-se mais freqüentemente normal neste grupo, quando comparados casos típicos e atípicos. A expansão GAA em homozigose foi detectada em 17 casos (68%) - todos típicos e, em 8 (32%) (6 atípicos e 2 típicos), não foi observada nenhuma expansão, excluindo-se o diagnóstico de ataxia de Friedreich. Deformidade de pés, anormalidades cardíacas e alguns achados neurológicos ocorreram mais freqüentemente, nos casos com expansão GAA, contudo, sinais de comprometimento dos pares cranianos e alterações dos achados tomográficos foram detectados menos frequentemente do que em pacientes sem expansão. DISCUSSÃO: A análise molecular é imprescindível para o diagnóstico de ataxia de Friedreich, não só para os casos típicos como também para os atípicos. Não há qualquer correlação entre o genótipo e o fenótipo. O diagnóstico baseado apenas nos achados clínicos é limitado, embora facilite a triagem para melhor selecionar os casos suspeitos que merecem ser testados. A dosagem sérica da vitamin E é recomendada , especialmente nos casos sem expansão GAA

Aspectos sistemáticos, paleobiogeográficos e paleoclimáticos dos mamíferos quaternários de Fazenda Nova, PE, nordeste do Brasil

The fossil mammals from the Fazenda Nova locality, Northeastern Brazil, represent an interval older than the Pleistocene-Holocene transition and include Xenarthra, Glyptodontidae, Glyptatelinae (with Pachyarmatherium sp.), Glyptodontinae, Glyptotheriini, Hoplophorinae indet., Pampatheriidae (with Holmesina cf. H. paulacoutoi), Megalonychidae, gen. et sp. indet., Megatheriidae (represented by Eremotherium laurillardi), Notoungulata, Toxodontinae (with Toxodon sp.), and Proboscidea (represented by Stegomastodon waringi). This paper reports and discusses the fi rst record of the North American glyptodont Glyptotheriini in Brazil, the first occurrence of Pachyarmatherium in Quaternary rocks of Pernambuco State, and the taxonomic history of the problematical taxon Chlamydotherium. OSL dating of the sediments and ESR dating of Stegomastodon teeth placed the Fazenda Nova deposits between 58.900 e 63.800 yr BP, which is equivalent to the IOS 3 and the Middle Wisconsin interstadial event recorded in the northern Andean South America. The mammal fauna from Fazenda Nova shows affinities with other southeastern and northeastern Brazilian faunas and, by the presence of Glyptotheriini and Pachyarmatherium, with those from northern South America, Central America and southern North American faunas, suggesting a warm and wet climate to the region at late Pleistocene. Key words: mammals, late Pleistocene, taxonomy, paleoclimate, ESR and OSL ages, Brazil.Os mamíferos fósseis de Fazenda Nova, na região Nordeste do Brasil, são representativos de um intervalo mais antigo que a transição Pleistoceno- Holoceno. Incluem Xenarthra, Glyptodontidae, Glyptatelinae (representado por Pachyarmatherium sp.), Glyptodontinae, Glyptotheriini, Hoplophorinae gen. et sp. indet., Pampatheriidae (representado por Holmesina cf. H. paulacoutoi), Megalonychidae gen. et sp. indet., Megatheriidae (Eremotherium laurillardi), Notoungulata, Toxodontinae (representado por Toxodon sp.) e Proboscidea (cuja forma conhecida é Stegomastodon waringi). Registra-se e discute-se neste artigo a ocorrência inédita de representantes da tribo norteamericana Glyptotheriini no Brasil, bem como do gênero Pachyarmatherium no Estado de Pernambuco, e se apresenta o histórico do tratamento taxonômico do táxon Chlamydotherium. Datações por Luminescência Opticamente Estimulada (LOE) nos sedimentos e por Ressonância Paramagnética Eletronica (EPR) nos dentes associados de Stegomastodon posicionam a fauna de Fazenda Nova entre 58.900 e 63.800 anos AP, equivalente ao estágio isotópico IOS 3 e ao evento interstadial wisconsiniano médio, registrado na região andina norte da América do Sul. O conjunto da fauna mostra afinidades com outras do sudeste e nordeste do Brasil e a presença de Glyptotheriini e Pachyarmatherium, com aquelas do norte da América do Sul, da América Central e do sul da América do Norte, e sugere condições de clima quente e úmido para a época da deposição. Palavras-chave: mamíferos, Pleistoceno Superior, taxonomia, paleoclima, datações EPR e LOE, Brasil