151 research outputs found

    Laser Raman diagnostics in subsonic and supersonic turbulent jet diffusion flames

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    Ultraviolet (UV) spontaneous vibrational Raman scattering combined with laser-induced predissociative fluorescence (LIPF) is developed for temperature and multi-species concentration measurements. Simultaneous measurements of temperature, major species (H2, O2, N2, H2O), and minor species (OH) concentrations are made with a 'single' narrow band KrF excimer laser in subsonic and supersonic lifted turbulent hydrogen-air diffusion flames. The UV Raman system is calibrated with a flat-flame diffusion burner operated at several known equivalence ratios from fuel-lean to fuel-rich. Temperature measurements made by the ratio of Stokes/anti-Stokes signal and by the ideal gas law are compared. The single shot measurement precision for concentration and temperature measurement is 5 to 10 pct. Calibration constants and bandwidth factors are determined from the flat burner measurements and used in a data reduction program to arrive at temperature and species concentration measurements. These simultaneous measurements of temperature and multi-species concentrations allow a better understanding of the complex turbulence-chemistry interactions and provide information for the input and validation of CFD models

    Industrial constructions of publics and public knowledge: a qualitative investigation of practice in the UK chemicals industry

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    This is a post print version of the article. The official published version can be obtained from the link below - © 2007 by SAGE PublicationsWhile the rhetoric of public engagement is increasingly commonplace within industry, there has been little research that examines how lay knowledge is conceptualized and whether it is really used within companies. Using the chemicals sector as an example, this paper explores how companies conceive of publics and "public knowledge," and how this relates to modes of engagement/communication with them. Drawing on qualitative empirical research in four companies, we demonstrate that the public for industry are primarily conceived as "consumers" and "neighbours," having concerns that should be allayed rather than as groups with knowledge meriting engagement. We conclude by highlighting the dissonance between current advocacy of engagement and the discourses and practices prevalent within industry, and highlight the need for more realistic strategies for industry/public engagement.Funding was received from the ESRC Science in Society Programme

    Picosecond time-resolved fluorescence of phycobiliproteins

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    The α- and β-subunits of C-phycocyanin from Mastigocladus laminosus were prepared according to revised procedures. Both subunits are isolated as dimers, which can be dissociated into monomers with detergent mixtures. The fluorescence decay kinetics are similar for the respective monomers and dimers. In no case could they be fitted by only one (α-subunit) or two exponentials (β-subunit) which are predicted by theory for samples with a unique chromophore—protein arrangement containing one and two chromophores, respectively. It is suggested that there exists a heterogeneity among the chromophores of the subunits, which may persist in the highly aggregated complexes present in cyanobacterial antennas

    PHOTOCHEMISTRY OF PHYCOBILIPROTEINS

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    Native PEC from the cyanobacterium, Mastigocladus laminosus, and its isolated α-subunit show photoreversibly photochromic reactions with difference-maxima around 502 and 570 nm in the spectral region of the α-84 phycoviolobilin chromophore. (b) Native PEC and its β-subunit show little if any reversible photochemistry in the 600–620 nm region, where the phycocyanobilin chromophores on the β-subunit absorb maximally, (c) Reversible photochemistry is retained in ureadenatured PEC at pH = 7.0 or pH ≤ 3. The difference maxima are shifted to 510 and 600 nm, and the amplitudes are decreased. An irreversible absorbance increase occurs around 670 nm (pH ≤ 3). (d) The amplitude of the reversible photoreaction difference spectrum is maximum in the presence of 4–5 M urea or 1 M KSCN, conditions known to dissociate phycobiliprotein aggregates into monomers. At the same time, the phycocyanobilin chromophore(s) are bleached irreversibly, (e) The amplitude becomes very small in high aggregates, e.g. in phycobilisomes. (f) In a reciprocal manner, the phototransformation of native PEC leads to a reversible shift of its aggregation equilibrium between trimer and monomer. The latter is favored by orange, the former by green light, (g) It is concluded that the phycoviolobilin chromophore of PEC is responsible for reversible photochemistry in PEC, and that there is not only an influence of aggregation state on photochemistry, but also vice versa an effect of the status of the chromophore on aggregation state. This could constitute a primary signal in the putative function as sensory pigment, either directly, or indirectly via the release of other polypeptides, via photodynamic effects, or the like

    Critical success factors for embedding carbon management in organizations: lessons from the UK higher education sector

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    Organizations are under increasing pressure from governments and stakeholders to reduce carbon emissions from their business operations for climate change mitigation. Universities are not exempt from this challenge and are operating in a complex external environment, not least responding to the UK government's Climate Change Act 2008 (80% carbon reductions by 2050 as per 1990 baseline). In 2012–2013, the UK Higher Education (HE) sector consumed 7.9 billion kWh of energy and produced 2.3 million tonnes of carbon emissions. This indicates the scale of the challenge and carbon management is central to reduce carbon emissions. However, effective processes for implementing and embedding carbon management in organizations in general, and universities in particular, have yet to be realized. This paper explores the critical success factors (CSFs) for embedding carbon management in universities and, more widely, in organizations. This exploratory study adopted a mixed-methods approach including the content analysis of universities' carbon management plans alongside semi-structured interviews in the UK HE sector. The paper identifies six key factors for successfully embedding carbon management that are pertinent not just for the HE sector, but to organizations broadly: senior management leadership; funding and resources; stakeholder engagement; planning; governance and management; and evaluation and reporting

    Hum Mol Genet

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    Gene transcription is controlled by transcriptional regulators acting with specific co-regulators to allow gene activation and repression. Here, we report the identification of the KRAB-containing zinc-finger transcriptional regulator, ZBRK1, as interaction partner of the SCA2 gene product ataxin-2. Furthermore, we discovered that an elevated ZBRK1 level resulted in increased ataxin-2 levels, whereas interference on transcriptional and protein levels of ZBRK1 yielded reduced ataxin-2 levels, suggesting that a complex comprising ZBRK1 and ataxin-2 regulates SCA2 gene transcription. A bioinformatic analysis utilizing the known ZBRK1 consensus DNA binding motif revealed ZBRK1 binding sites in the SCA2 promoter. These predicted sites were experimentally validated by chromatin-immunoprecipitation experiments along with luciferase-based promoter analyses corroborating that SCA2 gene transcription is controlled by a ZBRK1/ataxin-2 complex. Finally, we demonstrate that SCA2 gene transcription is significantly reduced in colon tumours possessing low ZBRK1 transcripts. Thus, our results provide first evidence that ataxin-2 acts as a co-regulator of ZBRK1 activating its own transcription, thereby representing the first identified ZBRK1 co-activator

    A hydraulically driven colonoscope

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    BACKGROUND: Conventional colonoscopy requires a high degree of operator skill and is often painful for the patient. We present a preliminary feasibility study of an alternative approach where a self-propelled colonoscope is hydraulically driven through the colon. METHODS: A hydraulic colonoscope which could be controlled manually or automatically was developed and assessed in a test bed modelled on the anatomy of the human colon. A conventional colonoscope was used by an experienced colonoscopist in the same test bed for comparison. Pressures and forces on the colon were measured during the test. RESULTS: The hydraulic colonoscope was able to successfully advance through the test bed in a comparable time to the conventional colonoscope. The hydraulic colonoscope reduces measured loads on artificial mesenteries, but increases intraluminal pressure compared to the colonoscope. Both manual and automatically controlled modes were able to successfully advance the hydraulic colonoscope through the colon. However, the automatic controller mode required lower pressures than manual control, but took longer to reach the caecum. CONCLUSIONS: The hydraulic colonoscope appears to be a viable device for further development as forces and pressures observed during use are comparable to those used in current clinical practice

    The Impact of Symbolic and Substantive Actions on Environmental Legitimacy

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    Drawing on institutional theory and insights from stakeholder theory and impression management, we empirically analyze the impact of both environmental symbolic polices (participation in voluntary environmental programs, green trademarks, environmental-dedicated board committees, environmental pay policies and community communication) and substantive actions (environmental patents and pollution prevention practices) on environmental legitimacy. We show that (1) symbolic actions have a weaker positive effect on legitimacy than substantive actions, (2) that the impact of symbolic actions is greater when they are combined with substantive actions, (3) that this impact is only short-term while substantive actions have both short- and long-term effects
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