743 research outputs found

    Mutagen specificity and potency in micro-organisms

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    Seasonal cycle in atmospheric HCl at 45 deg S

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    High resolution Fourier transform infrared interferometric atmospheric solar absorption measurements have been performed at the National Institute for Water and Atmospheric Research Laboratory at Lauder, New Zealand on a routine basis since October 1989. This laboratory has been selected as the Mid-latitude Charter Site of the Network for the Detection of Stratospheric Change and is at a latitude of 45 deg S. Particular attention has been paid to the absorption by atmospheric hydrogen chloride at 2925.9 cm(exp -1) and in this paper the results of the seasonal cycle in CHl above Lauder will be presented. Because of the very clean troposphere at this site, the CHl column measured from the ground is essentially a stratospheric column measurement

    Dynamical Masses for Pre-Main Sequence Stars: A Preliminary Physical Orbit for V773 Tau A

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    We report on interferometric and radial-velocity observations of the double-lined 51-d period binary (A) component of the quadruple pre-main sequence (PMS) system V773 Tau. With these observations we have estimated preliminary visual and physical orbits of the V773 Tau A subsystem. Among other parameters, our orbit model includes an inclination of 66.0 ±\pm 2.4 deg, and allows us to infer the component dynamical masses and system distance. In particular we find component masses of 1.54 ±\pm 0.14 and 1.332 ±\pm 0.097 M_{\sun} for the Aa (primary) and Ab (secondary) components respectively. Our modeling of the subsystem component spectral energy distributions finds temperatures and luminosities consistent with previous studies, and coupled with the component mass estimates allows for comparison with PMS stellar models in the intermediate-mass range. We compare V773 Tau A component properties with several popular solar-composition models for intermediate-mass PMS stars. All models predict masses consistent to within 2-sigma of the dynamically determined values, though some models predict values that are more consistent than others.Comment: ApJ in press; 25 pages, 6 figures; data tables available in journal versio

    Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam

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    The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air–oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m⁻¹) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m⁻¹ where the advancing air–oil–solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil–particle systems except for cases where θ is <60°. For oils of tension >24 mN m⁻¹ with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries

    Oceanospirillales containing the DMSP lyase DddD are key utilisers of carbon from DMSP in coastal seawater

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    Background: Ubiquitous and diverse marine microorganisms utilise the abundant organosulfur molecule dimethylsulfoniopropionate (DMSP), the main precursor of the climate-active gas dimethylsulfide (DMS), as a source of carbon, sulfur and/or signalling molecules. However, it is currently difficult to discern which microbes actively catabolise DMSP in the environment, why they do so and the pathways used. Results: Here, a novel DNA-stable isotope probing (SIP) approach, where only the propionate and not the DMS moiety of DMSP was 13C-labelled, was strategically applied to identify key microorganisms actively using DMSP and also likely DMS as a carbon source, and their catabolic enzymes, in North Sea water. Metagenomic analysis of natural seawater suggested that Rhodobacterales (Roseobacter group) and SAR11 bacteria were the major microorganisms degrading DMSP via demethylation and, to a lesser extent, DddP-driven DMSP lysis pathways. However, neither Rhodobacterales and SAR11 bacteria nor their DMSP catabolic genes were prominently labelled in DNA-SIP experiments, suggesting they use DMSP as a sulfur source and/or in signalling pathways, and not primarily for carbon requirements. Instead, DNA-SIP identified gammaproteobacterial Oceanospirillales, e.g. Amphritea, and their DMSP lyase DddD as the dominant microorganisms/enzymes using DMSP as a carbon source. Supporting this, most gammaproteobacterial (with DddD) but few alphaproteobacterial seawater isolates grew on DMSP as sole carbon source and produced DMS. Furthermore, our DNA-SIP strategy also identified Methylophaga and other Piscirickettsiaceae as key bacteria likely using the DMS, generated from DMSP lysis, as a carbon source. Conclusions: This is the first study to use DNA-SIP with 13C-labelled DMSP and, in a novel way, it identifies the dominant microbes utilising DMSP and DMS as carbon sources. It highlights that whilst metagenomic analyses of marine environments can predict microorganisms/genes that degrade DMSP and DMS based on their abundance, it cannot disentangle those using these important organosulfur compounds for their carbon requirements. Note, the most abundant DMSP degraders, e.g. Rhodobacterales with DmdA, are not always the key microorganisms using DMSP for carbon and releasing DMS, which in this coastal system were Oceanospirillales containing DddD. [MediaObject not available: see fulltext.]

    Scoping review of priority setting of research topics for musculoskeletal conditions

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    Objective Describe research methods used in priority-setting exercises for musculoskeletal conditions and synthesise the priorities identified. Design Scoping review. Setting and population Studies that elicited the research priorities of patients/consumers, clinicians, researchers, policy-makers and/or funders for any musculoskeletal condition were included. Methods and analysis We searched MEDLINE and EMBASE from inception to November 2017 and the James Lind Alliance top 10 priorities, Cochrane Priority Setting Methods Group, and Cochrane Musculoskeletal and Back Groups review priority lists. The reported methods and research topics/questions identified were extracted, and a descriptive synthesis conducted. Results Forty-nine articles fulfilled our inclusion criteria. Methodologies and stakeholders varied widely (26 included a mix of clinicians, consumers and others, 16 included only clinicians, 6 included only consumers or patients and in 1 participants were unclear). Only two (4%) reported any explicit inclusion criteria for priorities. We identified 294 broad research priorities from 37 articles and 246 specific research questions from 17 articles, although only four (24%) of the latter listed questions in an actionable format. Research priorities for osteoarthritis were identified most often (n=7), followed by rheumatoid arthritis (n=4), osteoporosis (n=4) and back pain (n=4). Nearly half of both broad and specific research priorities were focused on treatment interventions (n=116 and 111, respectively), while few were economic (n=8, 2.7% broad and n=1, 0.4% specific), implementation (n=6, 2% broad and n=4, 1.6% specific) or health services and systems research (n=15, 5.1% broad and n=9, 3.7% specific) priorities. Conclusions While many research priority-setting studies in the musculoskeletal field have been performed, methodological limitations and lack of actionable research questions limit their usefulness. Future studies should ensure they conform to good priority-setting practice to ensure that the generated priorities are of maximum value. PROSPERO registration number CRD42017059250

    The economic and innovation contribution of universities: a regional perspective

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    Universities and other higher education institutions (HEIs) have come to be regarded as key sources of knowledge utilisable in the pursuit of economic growth. Although there have been numerous studies assessing the economic and innovation impact of HEIs, there has been little systematic analysis of differences in the relative contribution of HEIs across regions. This paper provides an exploration of some of these differences in the context of the UK’s regions. Significant differences are found in the wealth generated by universities according to regional location and type of institution. Universities in more competitive regions are generally more productive than those located in less competitive regions. Also, traditional universities are generally more productive than their newer counterparts, with university productivity positively related to knowledge commercialisation capabilities. Weaker regions tend to be more dependent on their universities for income and innovation, but often these universities under-perform in comparison to counterpart institutions in more competitive regions. It is argued that uncompetitive regions lack the additional knowledge infrastructure, besides universities, that are more commonly a feature of more competitive regions
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