148 research outputs found

    Hybrids Between Meadow and Smooth Bromegrass: A New Forage Crop for Canada

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    Smooth bromegrass (Bromus inermis Leyss.) has been an important hay grass in the agricultural regions of western Canada for approximately 50 years. Meadow bromegrass (B. riparius Rehm.) has become the most important pasture species in this region over the last 15 years. It is possible to produce hybrids between these species, which could lead to the development of a type of bromegrass which would be useful for both hay and pasture purposes

    Recognition of Bromus Richardsonii and B. Ciliatus: Evidence from Morphology, Cytology, and DNA Fingerprinting (Poaceae: Bromeae)

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    Since our goal was to determine characteristic differences between Bromus richardsonii and B. ciliates, a discriminate analysis (DA), principal components analysis (PCA), multidimensional scaling (MDS), bivariate analysis, and an amplified fragment length polymorphisms (AFLP) analysis were undertaken on 93 herbarium specimens and 31 field-collected populations. A cytological survey of B. ciliates, B. richardsonii, and B. mucroglumis confirm previous reports that the first species is diploid (2n = 14) and the latter two are tetraploid (2n = 28). All taxa were correctly classified in the DA and important characters for each of the species were identified. Bromus richardsonii has lemmas with scattered hairs on the lower half between the mid nerve and margins [glabrous in B. ciliatus], anthers (1.2) 1.6-2.7 (3.4) mm long [(0.9) 1-1.4 (1.6) mm long in B. ciliatus], second glumes (7.8) 8.9 - 11.3 (13.2) mm long [(6.2) 7.1-8.5 (9.5) in B. ciliatus); and basal sheaths with dense, short to medium hairs [glabrous or with long hairs in B. ciliatus]. The PCA easily separated B. ciliatus and B. richardsonii into two well-defined groups and MDS mirrored the principal components analysis but displayed more overlap of individuals between the two groups. The AFLP-derived UPGMA dendrogram separated 154 individuals into two distinct clusters, one consisting entirely of B. ciliatus individuals and the other consisting of B. richardsonii individuals with six individuals of B. mucroglumis embedded within. Our study clearly indicates that there are distinctive morphological, cytological, and genetic differences to distinguish B. richardsonii and B. ciliatus as separate species

    The Impact of Atmospheric Fluctuations on Degree-scale Imaging of the Cosmic Microwave Background

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    Fluctuations in the brightness of the Earth's atmosphere originating from water vapor are an important source of noise for ground-based instruments attempting to measure anisotropy in the Cosmic Microwave Background. This paper presents a model for the atmospheric fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site.Comment: 29 pages, 7 figures, 1 table, appears in The Astrophysical Journa

    Adsorption induced reconstruction of the Cu(110) surface

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    The formation of the O/Cu(110)-(2 Ă— 1) and H/Cu(110)-(1 Ă— 2) superstructures has been investigated by a LEED beam profile analysis. The oxygen induced reconstruction proceeds at later stages by creation of holes on flat terraces. This could not be observed at the hydrogen induced missing row reconstruction. The formation of the missing row structure proceeds most probably via nucleation at steps and subsequent growth of (1 Ă— 2) islands. The influence of different distributions of steps and islands on beam profiles is discussed

    Hydrodynamic gene delivery in human skin using a hollow microneedle device

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    Microneedle devices have been proposed as a minimally invasive delivery system for the intradermal administration of nucleic acids, both plasmid DNA (pDNA) and siRNA, to treat localised disease or provide vaccination. Different microneedle types and application methods have been investigated in the laboratory, but limited and irreproducible levels of gene expression have proven to be significant challenges to pre-clinical to clinical progression. This study is the first to explore the potential of a hollow microneedle device for the delivery and subsequent expression of pDNA in human skin. The regulatory approved MicronJet600® (MicronJet hereafter) device was used to deliver reporter plasmids (pCMVβ and pEGFP-N1) into viable excised human skin. Exogenous gene expression was subsequently detected at multiple locations that were distant from the injection site but within the confines of the bleb created by the intradermal bolus. The observed levels of gene expression in the tissue are at least comparable to that achieved by the most invasive microneedle application methods e.g. lateral application of a microneedle. Gene expression was predominantly located in the epidermis, although also evident in the papillary dermis. Optical coherence tomography permitted real time visualisation of the sub-surface skin architecture and, unlike a conventional intradermal injection, MicronJet administration of a 50 μL bolus appears to create multiple superficial microdisruptions in the papillary dermis and epidermis. These were co-localised with expression of the pCMVβ reporter plasmid. We have therefore shown, for the first time, that a hollow microneedle device can facilitate efficient and reproducible gene expression of exogenous naked pDNA in human skin using volumes that are considered to be standard for intradermal administration, and postulate a hydrodynamic effect as the mechanism of gene delivery

    TGFβ induces a SAMHD1-independent post-entry restriction to HIV-1 infection of human epithelial Langerhans cells

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    Sterile alpha motif (SAM) and histidine-aspartic (HD) domains protein 1 (SAMHD1) was previously identified as a critical post-entry restriction factor to HIV-1 infection in myeloid dendritic cells. Here we show that SAMHD1 is also expressed in epidermis-isolated Langerhans cells (LC), but degradation of SAMHD1 does not rescue HIV-1 or vesicular stomatitis virus G-pseudotyped lentivectors infection in LC. Strikingly, using Langerhans cells model systems (mutz-3-derived LC, monocyte-derived LC [MDLC], and freshly isolated epidermal LC), we characterize previously unreported post-entry restriction activity to HIV-1 in these cells, which acts at HIV-1 reverse transcription, but remains independent of restriction factors SAMHD1 and myxovirus resistance 2 (MX2). We demonstrate that transforming growth factor-β signaling confers this potent HIV-1 restriction in MDLC during their differentiation and blocking of mothers against decapentaplegic homolog 2 (SMAD2) signaling in MDLC restores cells’ infectivity. Interestingly, maturation of MDLC with a toll-like receptor 2 agonist or transforming growth factor-α significantly increases cells’ susceptibility to HIV-1 infection, which may explain why HIV-1 acquisition is increased during coinfection with sexually transmitted infections. In conclusion, we report a SAMHD1-independent post-entry restriction in MDLC and LC isolated from epidermis, which inhibits HIV-1 replication. A better understanding of HIV-1 restriction and propagation from LC to CD4+ T cells may help in the development of new microbicides or vaccines to curb HIV-1 infection at its earliest stages during mucosal transmission

    The Early Positive Approaches to Support (E-PAtS) study: study protocol for a feasibility cluster randomised controlled trial of a group programme (E-PAtS) for family caregivers of young children with intellectual disability

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    Background: Children with intellectual disability have an IQ < 70, associated deficits in adaptive skills and are at increased risk of having clinically concerning levels of behaviour problems. In addition, parents of children with intellectual disability are likely to report high levels of mental health and other psychological problems. The Early Positive Approaches to Support (E-PAtS) programme for family caregivers of young children (5 years and under) with intellectual and developmental disabilities is a group-based intervention which aims to enhance parental psychosocial wellbeing and service access and support positive development for children. The aim of this study is to assess the feasibility of delivering E-PAtS to family caregivers of children with intellectual disability by community parenting support service provider organisations. The study will inform a potential, definitive RCT of the effectiveness and cost-effectiveness of E-PAtS. / Methods: This study is a feasibility cluster randomised controlled trial, with embedded process evaluation. Up to 2 family caregivers will be recruited from 64 families with a child (18 months to 5 years) with intellectual disability at research sites in the UK. Participating families will be allocated to intervention: control on a 1:1 basis; intervention families will be offered the E-PAtS programme immediately, continuing to receive usual practice, and control participants will be offered the opportunity to attend the E-PAtS programme at the end of the follow-up period and will continue to receive usual practice. Data will be collected at baseline, 3 months post-randomisation and 12 months post-randomisation. The primary aim is to assess feasibility via the assessment of: recruitment of service provider organisations; participant recruitment; randomisation; retention; intervention adherence; intervention fidelity and the views of participants, intervention facilitators and service provider organisations regarding intervention delivery and study processes. The secondary aim is preliminary evaluation of a range of established outcome measures for individual family members, subsystem relationships and overall family functioning, plus additional health economic outcomes for inclusion in a future definitive trial. / Discussion: The results of this study will inform a potential future definitive trial, to evaluate the effectiveness and cost-effectiveness of the E-PAtS intervention to improve parental psychosocial wellbeing. Such a trial would have significant scientific impact internationally in the intellectual disability field. / Trial registration: ISRCTN7041947
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