2,636 research outputs found

    Characterization of a rare analphoid supernumerary marker chromosome in mosaic

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    Abstract publicado em: Chromosome Research. 2015;23(Suppl 1):67-8. doi:10.1007/s10577-015-9476-6Analphoid supernumerary marker chromosomes (SMCs) are a rare subclass of SMCs C-band-negative and devoid of alpha-satellite DNA. These marker chromosomes cannot be identified unambiguously by conventional banding techniques alone being necessary to apply molecular cytogenetic methods in favour of a detailed characterization. In this work we report an analphoid SMC involving the terminal long arm of chromosome 7, in 9 years-old boy with several dysmorphic features and severe development delay. Cytogenetic analysis revealed a mosaic karyotype with the presence of an extra SMC, de novo, in 20 % of lymphocytes and 73 % of fibroblast cells. FISH analysis with alpha-satellite probes for all chromosomes, whole chromosome painting probe for chromosome 7, and D7S427 and TelVysion 7q probes, allowed establishing the origin of the SMC as an analphoidmarker resulting of an invdup rearrangement of 7q36-qter region. Affimetrix CytoScan HD microarray analysis, redefined the SMC to arr[hg19] 7q35(143696249-159119707)×2~3, which correspond to a gain of 15.42 Mb and encloses 67 OMIM genes, 16 of which are associated to disease. This result, combined with detailed clinical description, will provide an important means for better genotype-phenotype correlation and a more suitable genetic counselling to the patient and his parents, despite the additional difficulty resulting from being a mosaic (expression varies in different tissues). Analphoid SMCs derived from chromosome 7 are very rare, with only three cases reported so far. With this case we hope contribute to a better understanding of this type of chromosome rearrangements which are difficult for genetic counselling

    Spatial resolution on a small animal RPC-PET prototype operating under magnetic field

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    It has been demonstrated in previous work that the RPC-PET technology is able to deliver radioisotope image resolutions approaching the physical limits of the PET principle. Here we study, by simulation, the effect of the magnetic field on the positron range to evaluate whether the spatial resolution of the RPC-PET could be improved by using an intense magnetic field. Six positron emitters of interest to small animal PET imaging (18F, 11C, 15O, 68G, 62Cu and 86Y) are considered. Results suggest that a three-fold improvement on the spatial resolution may be obtained under a magnetic field of 10 T for the higher energy radioisotopes like 86Y or 62Cu, and by about 20% for the lower energy ones, like 18F or 11C.http://www.sciencedirect.com/science/article/B6TVD-4KV4MR8-15/1/efa4356ba16a85fd7740937bd0e672a

    Very high position resolution gamma imaging with resistive plate chambers

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    In this study we present experimental results from a first prototype of a positron emission tomography system based on the resistive plate chamber (RPC) technology. The system is composed of two counting heads, each one containing 16 single-gap RPC detectors capable of detecting the photon interaction point in the transaxial plane. Uniformity studies were performed for image resolution and sensitivity, yielding a rather uniform image resolution close to 0.3 mm FWHM across the field of view. The contribution of the photons noncolinearity effect to the intrinsic spatial resolution was also studied, causing a variation from 0.52 to 0.63 mm when the system diameter ranges from 60 to 120 mm, in agreement with calculations.http://www.sciencedirect.com/science/article/B6TJM-4K5HV7F-9/1/7b655e08199d2b28acc8050106c2271

    Alternativa agroflorestal para pequenos produtores agrícolas em áreas de terra firme do município de Santarém, Pará.

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    Heterocyclic acetals in Madeira wines

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    The maturation of Madeira wines usually involves exposure to relatively high temperatures which affect the aroma and flavour composition leading to the formation of the typical and characteristic bouquet of these wines. The formation of heterocyclic acetals (1,3-dioxanes and 1,3-dioxolanes) was investigated in order to determine levels and for possible use as indicators of wine age. The results show a linear correlation of the investigated acetals with wine age but suggest that the acetalization reaction is not particularly affected by the drastic oxidative conditions observed during maturation

    Sistema agroflorestal em área de pequeno produtor na região do Tapajós, Estado do Pará: avaliação após doze anos de implantado.

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