2,124 research outputs found
Complex patterns of male germline instability and somatic mosaicism in myotonic dystrophy type 1
The genetic basis of myotonic dystrophy type 1 (DM1) is the expansion of a CTG repeat in the 3' untranslated region of DM1PK . Once into the disease range, the repeat becomes highly unstable and is biased toward expansion in both somatic and germline tissues. Intergenerational differences usually reveal an increase in allele length, concordant with the clinical anticipation characteristic of DM1, but there have also been cases with intergenerational contractions of the repeat length, accompanied by apparent anticipation. In order to gain a better understanding of this intergenerational behaviour, we have obtained semen samples from six DM males and used single molecule analyses to compare the allele distributions present in their sperm and blood with those of their offspring. We have confirmed that the male germline mutational pathway is distinct from that of the soma, but the extent of variation is highly variable from one individual to another and not obviously correlated with progenitor allele length. Nonetheless, in all cases the alleles present in the father's sperm overlap with those observed in their offspring. These data also provide further indications that the interpretation of intergenerational transmissions by standard analyses is frequently compromised by the masking of germline differences by age-dependent somatic expansion in the parent
Modeling and manufacturability assessment of bistable quantum-dot cells
We have investigated the behavior of bistable cells made up of four quantum
dots and occupied by two electrons, in the presence of realistic confinement
potentials produced by depletion gates on top of a GaAs/AlGaAs heterostructure.
Such a cell represents the basic building block for logic architectures based
on the concept of Quantum Cellular Automata (QCA) and of ground state
computation, which have been proposed as an alternative to traditional
transistor-based logic circuits. We have focused on the robustness of the
operation of such cells with respect to asymmetries deriving from fabrication
tolerances. We have developed a 2-D model for the calculation of the electron
density in a driven cell in response to the polarization state of a driver
cell. Our method is based on the one-shot Configuration-Interaction technique,
adapted from molecular chemistry. From the results of our simulations, we
conclude that an implementation of QCA logic based on simple ``hole-arrays'' is
not feasible, because of the extreme sensitivity to fabrication tolerances. As
an alternative, we propose cells defined by multiple gates, where geometrical
asymmetries can be compensated for by adjusting the bias voltages. Even though
not immediately applicable to the implementation of logic gates and not
suitable for large scale integration, the proposed cell layout should allow an
experimental demonstration of a chain of QCA cells.Comment: 26 pages, Revtex, 13 figures, title and some figures changed and
minor revision
Barcelona Supercomputing Center: Science accelerator and producer of innovation
Supercomputing has become an accelerator; its use is now essential in almost all scientific disciplines. Established a little more than ten years ago, the Barcelona Supercomputing Center (BSC) provides computing services for the European scientific community, carries out in-depth research in different fields, collaborates with multiple research centers and develops technologies for different sectors of society. Based on its capabilities and the skills of the responsible team, the BSC is planning to enlarge both its facilities and its penetration into the scientific and industrial communities as one of the most powerful tools to develop complex research
Arquitecturas para la era de la máquina: análisis comparativo del Media-TIC y el Banc de Sang i Teixits
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Una nueva sociedad: hacia la rehabilitación
Peer Reviewe
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