198 research outputs found

    The edge-on spiral gravitational lens B1600+434

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    We present new observations of the gravitational lens (GL) system B1600+434, strongly suggesting that the lens is an edge-on spiral galaxy. These observations are used to constrain the mass model of the system, in particular the oblateness and velocity dispersion of the dark matter halo around the lensing galaxy. From an analytical model we find a lower limit on the halo oblateness q_\rmn{halo}=(c/a)_{\rho}\ga0.4; more detailed numerical models give a lower limit q_\rmn{h}\ga0.5. We determine an average halo velocity dispersion of Ļƒhalo=190Ā±15\sigma_{halo}=190\pm 15 km/s over all non-singular isothermal elliptical (NIE) halo models. Constraining the models to larger and more massive disks, decreases this average by only 10 km/s. A lower limit of \sigma_{halo}\ga 150 km/s is found, even for disk masses larger then the mass inside the Einstein radius. This lower limit indicates the need for a massive dark matter halo, contributing at least half of the mass inside the Einstein radius. Time delay calculations give (54Ā±3)/h50(54\pm3)/h_{50} days for the NIE halo model and (70Ā±4)/h50(70\pm4)/h_{50} days for the modified Hubble profile (MHP) halo model. Although the time delay for both NIE and MHP halo models is well constrained on our parameter grid, it strongly depends on the halo surface density profile. We furthermore find that the presence of a flat luminous mass distribution can severely alter the statistical properties of the lens.Comment: 35 pages including 10 PS-figures, and 4 tables. Accepted for publication by MNRA

    Crack formation and prevention in colloidal drops

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    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticlesopen0

    More than just a bracelet: the use of material symbolism to communicate love

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    There is growing recognition of the place of love in residential care for children (Smith, 2009). This paper is a critical analysis of a range of existing research on residential child care as well as studies of material culture and of care relationships more broadly. It argues that, despite increasing regulation and surveillance, adults and children find ways to show and feel love in the context of residential care. Whilst love may be regarded as something to be avoided or indeed prohibited in an adult/child care setting these deep bonds find expression in the everyday life of the children's home. By looking at love in this embodied way, the 'realness' of material things to assert connection and recognition of love (Layne, 2000) is examined. As Gorenstein (1996, p.8) suggests 'objects...[are] the perfect vehicles for conveying themes that are not commonly accepted in a community'. The paper emphasises the recognition of these symbolic and metaphorical forms of communication in practice

    Effects of canola proteins and hydrolysates on adipogenic differentiation of C3H10T/2 mesenchymal stem cells

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    Strappe, P ORCiD: 0000-0003-0100-0558This study assessed the ability of canola protein isolate (CPI) and enzymatic hydrolysates (CPHs) to inhibit adipogenic differentiation of C3H10T1/2 murine mesenchymal stem cells in vitro. Cell viability was maintained at concentrations of 60 Ī¼g/ml of sample. Cells treated with Alcalase hydrolysate demonstrated a higher reduction in anti-adipogenic differentiation through quantitation by oil-red O staining. qPCR analysis showed that CPI and CPH-treated cells significantly inhibited PPARĪ³ expression, a key transcription factor involved in adipocyte differentiation, as evident in an āˆ¼60-80% fold reduction of PPARĪ³ mRNA. Immunofluorescence staining for PPARĪ³ protein also showed a reduced expression in some treated cells when compared to differentiated untreated cells. The 50% inhibition concentration (IC50) of CPI, CPHs and their membrane ultrafiltration fractions on pancreatic lipase (PL) activity ranged between 0.75 and 2.5 mg/ml, (p < 0.05) for the hydrolysed and unhydrolysed samples. These findings demonstrate that CPI and CPHs contain bioactive components which can modulate in vitro adipocyte differentiation.Associated Grant:Australian Grains Research and Development Cooperation (GRDC)Associated Grant Code:UCS0001
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