541 research outputs found

    Theory of a general class of dissipative processes

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    General theory of dissipative periodic processes for systems defined by partial, functional, or neutral differential equation

    In the Name of Profit: Canada’s Mount Arrowsmith Biosphere Reserve as Economic Development and Colonial Placemaking

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    Taking a critical heritage approach to late modern naming and placemaking, we discuss how the power to name reflects the power to control people, their land, their past, and ultimately their future. Our case study is the Mount Arrowsmith Biosphere Reserve (MABR), a recently invented place on Vancouver Island, located in southwestern British Columbia, Canada. Through analysis of representations and landscape, we explore MABR as state-sanctioned branding, where a dehumanized nature is packaged for and marketed to wealthy ecotourists. Greenwashed by a feel-good “sustainability” discourse, MABR constitutes colonial placemaking and economic development, representing no break with past practices

    Charles Willson Peale at Belfield

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    A selection of the works of Charles Willson Peale executed between 1810 and 1821 while in residence at Belfield Farm; October 1971.https://digitalcommons.lasalle.edu/exhibition_catalogues/1004/thumbnail.jp

    Lyapunov Control on Quantum Open System in Decoherence-free Subspaces

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    A scheme to drive and manipulate a finite-dimensional quantum system in the decoherence-free subspaces(DFS) by Lyapunov control is proposed. Control fields are established by Lyapunov function. This proposal can drive the open quantum system into the DFS and manipulate it to any desired eigenstate of the free Hamiltonian. An example which consists of a four-level system with three long-lived states driven by two lasers is presented to exemplify the scheme. We have performed numerical simulations for the dynamics of the four-level system, which show that the scheme works good.Comment: 5 pages, 6 figure

    Gene induction during differentiation of human monocytes into dendritic cells: an integrated study at the RNA and protein levels

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    Changes in gene expression occurring during differentiation of human monocytes into dendritic cells were studied at the RNA and protein levels. These studies showed the induction of several gene classes corresponding to various biological functions. These functions encompass antigen processing and presentation, cytoskeleton, cell signalling and signal transduction, but also an increase in mitochondrial function and in the protein synthesis machinery, including some, but not all, chaperones. These changes put in perspective the events occurring during this differentiation process. On a more technical point, it appears that the studies carried out at the RNA and protein levels are highly complementary.Comment: website publisher: http://www.springerlink.com/content/ha0d2c351qhjhjdm

    Coordinate regulation of DNA methyltransferase expression during oogenesis

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    <p>Abstract</p> <p>Background</p> <p>Normal mammalian development requires the action of DNA methyltransferases (DNMTs) for the establishment and maintenance of DNA methylation within repeat elements and imprinted genes. Here we report the expression dynamics of <it>Dnmt3a </it>and <it>Dnmt3b</it>, as well as a regulator of DNA methylation, <it>Dnmt3L</it>, in isolated female germ cells.</p> <p>Results</p> <p>Our results indicate that these enzymes are coordinately regulated and that their expression peaks during the stage of postnatal oocyte development when maternal methylation imprints are established. We find that Dnmt3a, Dnmt3b, Dnmt3L and Dnmt1o transcript accumulation is related to oocyte diameter. Furthermore, DNMT3L deficient 15 dpp oocytes have aberrantly methylated <it>Snrpn</it>, <it>Peg3 </it>and <it>Igf2r </it>DMRs, but normal IAP and LINE-1 methylation levels, thereby highlighting a male germ cell specific role for DNMT3L in the establishment of DNA methylation at repeat elements. Finally, real-time RT-PCR analysis indicates that the depletion of either DNMT3L or DNMT1o in growing oocytes results in the increased expression of the <it>de novo </it>methyltransferase <it>Dnmt3b</it>, suggesting a potential compensation mechanism by this enzyme for the loss of one of the other DNA methyltransferases.</p> <p>Conclusion</p> <p>Together these results provide a better understanding of the developmental regulation of <it>Dnmt3a</it>, <it>Dnmt3b </it>and <it>Dnmt3L </it>at the time of <it>de novo </it>methylation during oogenesis and demonstrate that the involvement of DNMT3L in retrotransposon silencing is restricted to the male germ line. This in turn suggests the existence of other factors in the oocyte that direct DNA methylation to transposons.</p

    Loss of spermatogonia and wide-spread DNA methylation defects in newborn male mice deficient in DNMT3L

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    <p>Abstract</p> <p>Background</p> <p>Formation of haploid spermatozoa capable of fertilization requires proper programming of epigenetic information. Exactly how DNMT3L (DNA methyltransferase 3-Like), a postulated regulator of DNA methyltransferase activity, contributes to DNA methylation pattern acquisition during gametogenesis remains unclear. Here we report on the role of DNMT3L in male germ cell development.</p> <p>Results</p> <p>A developmental study covering the first 12 days following birth was conducted on a <it>Dnmt3L </it>mutant mouse model; lower germ cell numbers and delayed entry into meiosis were observed in <it>Dnmt3L</it><sup>-/- </sup>males, pointing to a mitotic defect. A temporal expression study showed that expression of <it>Dnmt3L </it>is highest in prenatal gonocytes but is also detected and developmentally regulated during spermatogenesis. Using a restriction enzyme qPCR assay (qAMP), DNA methylation analyses were conducted on postnatal primitive type A spermatogonia lacking DNMT3L. Methylation levels along 61 sites across chromosomes 4 and X decreased significantly by approximately 50% compared to the levels observed in <it>Dnmt3L</it><sup>+/+ </sup>germ cells, suggesting that many loci throughout the genome are marked for methylation by DNMT3L. More so, hypomethylation was more pronounced in regions of lower GC content than in regions of higher GC content.</p> <p>Conclusion</p> <p>Taken together, these data suggest that DNMT3L plays a more global role in genomic methylation patterning than previously believed.</p

    Evaluation of cowpea accessions for resistance to flower bud thrips (Megalurothrips sjostedti) in Mali

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    Open Access JournalFlower bud thrips (Megalurothrips sjostedti) is one of the most damaging pests to cowpea in Africa and varietal resistance is one of the effective approaches to minimize the pest damage. Study was conducted to assess variability among 117 genotypes in addition to two resistant (Sanzisabinli and TVu 1509) and one susceptible (Vita7) checks at Cinzana and N’Tarla locations under natural and artificial infestations of thrips. Parameters such as total number of pods per plant and damage scoring were used to assess the test entries. Genotypes CIPEA82672, Suivita2, TVu 1509 and Sanzisabinli were found highly tolerant, Diaye and TVu7677 moderately tolerant whilst nine genotypes were found tolerant to thrips attacks. CIPEA82672 and Suivita2 had higher grain yield than the resistant checks. Year by genotype, year by location and year by location by genotype interactions were significant for most traits. Genotype by genotype by environment (GGE) effect on yield showed CIPEA82672 most stable across both locations while Suivita2 was only stable at N’Tarla. High broad sense heritability (H2b) was observed for some traits such as damage scoring across locations. Highest genotypic coefficient of variation (GCV) of 81.24 and phenotypic coefficient of variation (PCV) of 75.62 were attributed to total number of pods per plant. Positive correlations were detected between the damage scoring and the number of adult thrips from Cinzana (R2= 0.264) and N’Tarla (R2= 0.603) locations. Confirmation of identified cowpea genotypes highly and moderately tolerant to thrips attacks could be used to improve farmers’ preferred cowpea genotypes susceptible to thrips

    Evaluation of cowpea accessions for resistance to flower bud thrips (Megalurothrips sjostedti) in Mali

    Get PDF
    Open Access JournalFlower bud thrips (Megalurothrips sjostedti) is one of the most damaging pests to cowpea in Africa and varietal resistance is one of the effective approaches to minimize the pest damage. Study was conducted to assess variability among 117 genotypes in addition to two resistant (Sanzisabinli and TVu 1509) and one susceptible (Vita7) checks at Cinzana and N’Tarla locations under natural and artificial infestations of thrips. Parameters such as total number of pods per plant and damage scoring were used to assess the test entries. Genotypes CIPEA82672, Suivita2, TVu 1509 and Sanzisabinli were found highly tolerant, Diaye and TVu7677 moderately tolerant whilst nine genotypes were found tolerant to thrips attacks. CIPEA82672 and Suivita2 had higher grain yield than the resistant checks. Year by genotype, year by location and year by location by genotype interactions were significant for most traits. Genotype by genotype by environment (GGE) effect on yield showed CIPEA82672 most stable across both locations while Suivita2 was only stable at N’Tarla. High broad sense heritability (H2b) was observed for some traits such as damage scoring across locations. Highest genotypic coefficient of variation (GCV) of 81.24 and phenotypic coefficient of variation (PCV) of 75.62 were attributed to total number of pods per plant. Positive correlations were detected between the damage scoring and the number of adult thrips from Cinzana (R2= 0.264) and N’Tarla (R2= 0.603) locations. Confirmation of identified cowpea genotypes highly and moderately tolerant to thrips attacks could be used to improve farmers’ preferred cowpea genotypes susceptible to thrips

    Platelet FcÎłRIIA-induced serotonin release exacerbates the severity of Transfusion-Related Acute Lung Injury in mice

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    Transfusion-related acute lung injury (TRALI) remains a major cause of transfusion-related fatalities. The mechanism of human antibody-mediated TRALI, especially the involvement of the Fcγ receptors, is not clearly established. Contrary to mice, human platelets are unique in their expression of the FcγRIIA/CD32A receptor, suggesting that our understanding of the pathogenesis of antibody-mediated TRALI is partial, as the current murine models incompletely recapitulate the human immunology. We evaluated the role of FcγRIIA/CD32A in TRALI using a humanized mouse model expressing the FcγRIIA/CD32A receptor. When challenged with a recombinant chimeric human immunoglobulin G1/mouse anti–major histocompatibility complex class I monoclonal antibody, these mice exhibited exacerbated alveolar edema and higher mortality compared with wild-type (WT) mice. Unlike in WT mice, monocytes/macrophages in CD32A(+) mice were accessory for TRALI initiation, indicating the decisive contribution of another cell type. Platelet activation was dramatically increased in CD32A(+) animals, resulting in their increased consumption and massive release of their granule contents. Platelet depletion prevented the exacerbation of TRALI in CD32A(+) mice but did not affect TRALI in WT animals. By blocking platelet serotonin uptake with fluoxetine, we showed that the severity of TRALI in CD32A(+) mice resulted from the serotonin released by the activated platelets. Furthermore, inhibition of 5-hydroxytryptamine 2A serotonin receptor with sarpogrelate, before or after the induction of TRALI, abolished the aggravation of lung edema in CD32A(+) mice. Our findings show that platelet FcγRIIA/CD32A activation exacerbates antibody-mediated TRALI and provide a rationale for designing prophylactic and therapeutic strategies targeting the serotonin pathway to attenuate TRALI in patients
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