Birds have played a central role in many biological disciplines, particularly ecology, evolution, and behavior. The chicken, as a model vertebrate, also represents an important experimental system ...for developmental biologists, immunologists, cell biologists, and geneticists. However, genomic resources for the chicken have lagged behind those for other model organisms, with only 1845 nonredundant full-length chicken cDNA sequences currently deposited in the EMBL databank. We describe a large-scale expressed-sequence-tag (EST) project aimed at gene discovery in chickens (http://www.chick.umist.ac.uk). In total, 339,314 ESTs have been sequenced from 64 cDNA libraries generated from 21 different embryonic and adult tissues. These were clustered and assembled into 85,486 contiguous sequences (contigs). We find that a minimum of 38% of the contigs have orthologs in other organisms and define an upper limit of 13,000 new chicken genes. The remaining contigs may include novel avian specific or rapidly evolving genes. Comparison of the contigs with known chicken genes and orthologs indicates that 30% include cDNAs that contain the start codon and 20% of the contigs represent full-length cDNA sequences. Using this dataset, we estimate that chickens have approximately 35,000 genes in total, suggesting that this number may be a characteristic feature of vertebrates.
Little is known about the molecular basis of organelle size control in eukaryotes. Cells of the biflagellate alga Chlamydomonas reinhardtii actively maintain their flagella at a precise length. ...Chlamydomonas mutants that lose control of flagellar length have been isolated and used to demonstrate that a dynamic process keeps flagella at an appropriate length 1, 2. To date, none of the proteins required for flagellar length control have been identified in any eukaryotic organism. Here, we show that a novel MAP kinase is crucial to enforcing wild-type flagellar length in C. reinhardtii. Null mutants of LF42, a gene encoding a protein with extensive amino acid sequence identity to a mammalian MAP kinase of unknown function, MOK 3, are unable to regulate the length of their flagella. The LF4 protein (LF4p) is localized to the flagella, and in vitro enzyme assays confirm that the protein is a MAP kinase. The long-flagella phenotype of lf4 cells is rescued by transformation with the cloned LF4 gene. The demonstration that a novel MAP kinase helps enforce flagellar length control indicates that a previously unidentified signal transduction pathway controls organelle size in C. reinhardtii.
El presente documento ilustra metodológicamente el diseño y la implementación de una solución VoIP, la cual integra la planta análoga (PBX) con el modulo de PBX del Elastix (IP-PBX), por medio de un ...Gateway de VoIP. Con el producto de esta investigación, desarrollada por el grupo INTEGRA, se permite el uso de nuevos servicios enfocados en el óptimo uso de las redes (telefonía y datos) usando servicios adicionales, como son: servidor de fax, servidor de mensajería instantánea, control y reporte detallado de llamadas, grabaciones y servicios adicionales como la recepción de fax y buzón de mensajes al correo electrónico como archivos adjuntos.
IrMn spin-valves for high density recording Childress, J.R.; Carey, M.J.; Wilson, R.J. ...
IEEE transactions on magnetics,
07/2001, Letnik:
37, Številka:
4
Journal Article, Conference Proceeding
Simple IrMn spin-valves are investigated for use in high density recording head sensors. Top-IrMn spin-valves of the form NiFeCr(40 /spl Aring/)/NiFe(32 /spl Aring/)/CoFe(5)/Cu(25 /spl ...Aring/)/CoFe(30 /spl Aring/)/IrMn(80 /spl Aring/)/Ta(50 /spl Aring/) were deposited by magnetron sputtering. By tailoring the pinned layer composition at the CoFe/IrMn interface to Co/sub 60/Fe/sub 40/, the exchange bias can be increased above 400 Oe with a GMR amplitude of about 12%. Recording heads were fabricated with total gap thicknesses down to 900 /spl Aring/, magnetic trackwidth down to 0.2 /spl mu/m and stripe height down to 0.3 /spl mu/m. The transfer curve characteristics are found to agree reasonably well with micromagnetic modeling. The model is then used to predict head sensitivity loss from the combination of insufficient exchange bias and short sensor stripe heights.
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