1,143 research outputs found

    A new CAE procedure for railway wheel tribological design

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    New demands are being imposed on railway wheel wear and reliability to increase the time between wheel reprofiling, improve safety and reduce total wheelset lifecycle costs. In parallel with these requirements, changes in railway vehicle missions are also occurring. These have led to the need to operate rolling stock on track with low as well as high radius curves; increase speeds and axle loads; and contend with a decrease in track quality due to a reduction in maintenance. These changes are leading to an increase in the severity of the wheel/rail contact conditions, which may increase the likelihood of wear or damage occurring. The aim of this work was to develop a new CAE design methodology to deal with these demands. The model should integrate advanced numerical tools for modelling of railway vehicle dynamics and suitable models to predict wheelset durability under typical operating conditions. This will help in designing wheels for minimum wheel and rail wear; optimising railway vehicle suspensions and wheel profiles; maintenance scheduling and the evaluation of new wheel materials. This work was carried out as part of the project HIPERWheel, funded by the European Community within the Vth Framework Programme

    The pervasive relevance of COVID-19 within routine paediatric palliative care consultations during the pandemic: a conversation analytic study

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    Background: The importance of caring for children with complex and serious conditions means that paediatric palliative care must continue during pandemics. The recent pandemic of Coronavirus Disease 2019 (COVID-19) provides a natural experiment to study health communication during pandemic times. However, it is unknown how communication within consultations might change during pandemics. Aim: This study, a sub-study of a larger project, aimed to examine real-world instances of communication in paediatric palliative care consultations prior to and during the COVID-19 pandemic to understand how clinicians and families talk about the pandemic. Design: Paediatric palliative care consultations prior to, during, and immediately following the initial peak of COVID-19 cases in Australia were video recorded and analysed using Conversation Analysis methods. Setting/Participants: Twenty-five paediatric palliative care consultations (including face-to-face outpatient, telehealth outpatient and inpatient consultations) were video recorded within a public children's hospital in Australia. Participants included 14 health professionals, 15 child patients, 23 adult family members and 5 child siblings. Results: There was a pervasive relevance of both serious and non-serious talk about COVID-19 within the consultations recorded during the pandemic. Topics typical of a standard paediatric palliative care consultation often led to discussion of the pandemic. Clinicians (55%) and parents (45%) initiated talk about the pandemic. Conclusions: Clinicians should not be surprised by the pervasiveness of COVID-19 or other pandemic talk within standard paediatric palliative care consultations. This awareness will enable clinicians to flexibly address family needs and concerns about pandemic-related matters that may impact health and wellbeing.Katie Ekberg, Lara Weinglass, Stuart Ekberg, Susan Danby and Anthony Herber

    Women and waterbirth: A systematic meta-synthesis of qualitative studies

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    Background: The practice of waterbirth is increasing worldwide and has been a feature of maternity services in the United Kingdom for over twenty years. The body of literature surrounding the practice focusses on maternal and neonatal outcomes comparing birth in and out of water. Aim: To undertake a review of qualitative studies exploring women's experiences of waterbirth. This understanding is pertinent when supporting women who birth in water. Methods: A literature search was conducted in databases British Nursing Index, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Maternity and Infant Care, Medline, Applied Social Sciences Index and Abstracts and Web of Science, using search terms waterbirth, labour/labor, childbirth, women, mothers, experience, perception and maternity care. Five primary research articles published between 2003 and 2018 which explored the views of women who had birthed in water were selected for inclusion. Using meta-ethnography, qualitative research studies were analysed and synthesised using the method of ‘reciprocal translational analysis’ identifying themes relating to women's experiences of birthing in water. Findings: Four themes were identified: women's knowledge of waterbirth; women's perception of physiological birth; water, autonomy and control; and waterbirth: easing the transition. Discussion and conclusion: Despite the paucity of qualitative studies exploring women's experiences of waterbirth, meta-synthesis of those that do exist suggested women identify positively with the choice. The experience of birthing in water appears to enhance a woman's sense of autonomy and control during childbirth suggesting waterbirth can be an empowering experience for women who choose it

    Managing the therapeutic relationship in online cognitive behavioural therapy for depression:Therapists' treatment of clients' contributions

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    This article examines how therapists and clients manage the therapeutic relationship in online psychotherapy. Our study focuses on early sessions of therapy involving 22 therapist-client pairs participating in online Cognitive Behavioural Therapy (CBT) for depression. Using Conversation Analysis (CA), we examine how therapists can orient to clients’ contributions, while also retaining control of the therapeutic trajectory. We report two practices that therapists can use, at their discretion, following clients’ responses to requests for information. The first, thanking, accepts clients’ responses, orienting to the neutral affective valence of those responses. The second, commiseration, orients to the negative affective valence of clients’ responses. We argue that both practices are a means by which therapists can simultaneously manage developing rapport, while also retaining control of the therapeutic process

    Managing clients’ expectations at the outset of online Cognitive Behavioural Therapy (CBT) for depression

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    Background\ud \ud Engaging clients in psychotherapy by managing their expectations is important for therapeutic success. Initial moments in first sessions of therapy are thought to afford an opportunity to establish a shared understanding of how therapy will proceed. However there is little evidence from analysis of actual sessions of therapy to support this.\ud \ud Objective\ud \ud This study utilised recordings to examine how therapists manage clients’ expectations during the first two sessions of online Cognitive Behavioural Therapy (CBT). \ud Methods Expectation management was investigated through conversation analysis of sessions from 176 client-therapist dyads involved in online CBT. The primary focus of analysis was expectation management during the initial moments of first sessions, with a secondary focus on expectations at subsequent points. \ud \ud Analysis\ud \ud Clients’ expectations for therapy were most commonly managed during the initial moments of first sessions of therapy. At this point, most therapists either outlined the tasks of the first and subsequent sessions (n=36), or the first session only (n=108). On other occasions (n = 32), no attempt was made to manage clients’ expectations by outlining what would happen in therapy. Observations of the interactional consequences of such an absence suggest clients may struggle to engage with the therapeutic process in the absence of appropriate expectation management by therapists. \ud \ud Conclusion\ud \ud Clients may more readily engage from the outset of therapy when provided with an explanation that manages their expectation of what is involved. Therapists can accomplish this by projecting how therapy will proceed, particularly beyond the initial session

    Mutational Analysis of the Analgesic Peptide DrTx(1-42) Revealing a Functional Role of the Amino-Terminal Turn

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    Background: DrTx(1-42) (a carboxyl-terminally truncated version of drosotoxin) is a potent and selective blocker of tetrodotoxin-resistant (TTX-R) Na + channels in rat dorsal root ganglion neurons with analgesic activity. This purpose is to identify key amino acids which are responsible for both blocking and analgesic effects of DrTx(1-42). Methods: On the basis of previous study, we designed five mutants of DrTx(1-42) (delN, D8A, D8K, G9A, and G9R) in the amino-terminal turn (N-turn) region, a proposed functional region located in the amino-terminus of the molecule. All these mutants were expressed in E.coli and purified by RP-HPLC. Electrophysiological properties of these analogues were examined by whole-cell patch-clamp recordings and their antinociceptive effects were investigated by the formalin test and acetic acid induced writhing test. Results: All the mutants except for G9A possess a similar secondary structure to that of DrTx(1-42), as identified by circular dichroism analysis. Three mutants (delN, D8A and G9A) were found almost inactive to TTX-R Na + channels, whereas D8K retains similar activity and G9R showed decreased potency when compared with the wild-type molecule. Consistent with the electrophysiological observations, D8K and G9R exhibited antinociceptive effects in the second phase (inflammatory pain) of the formalin test and the acetic acid induced writhing test, while delN, D8A and G9A lack such effects. Conclusions: Our results show that the N-turn is closely related to function of DrTx(1-42). The mutant (D8A) as a contro

    Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

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    Deep-eutectic solvents (DESs) are used as a promising alternative to aqueous solutions for the recovery of valuable metals from NdFeB magnets. A deep-eutectic solvent based on choline chloride and lactic acid (molar ratio 1 : 2) was used for the leaching of rare earths and other metals from NdFeB magnets. A process for the separation of Fe, B and Co from Nd and Dy in the deep-eutectic solvent was developed by using the ionic liquid tricaprylmethylammonium thiocyanate (Aliquat 336 SCN, [A336][SCN]) diluted in toluene (0.9 M). The extraction parameters were optimized and stripping of B was efficiently carried out by HCl, while EDTA was employed for the recovery of Fe and Co. The separation of Nd and Dy was assessed by using two different types of extractants, a mixture of trialkylphosphine oxides (Cyanex 923) and bis(2-ethylhexyl) phosphoric acid (D2EHPA). Based on the distribution ratios, separation factors and the ease of subsequent stripping, Cyanex 923 was chosen as the most effective extractant. The purified Dy present in the less polar phase was easily recovered by stripping with water, while the Nd present in the deep-eutectic solvent was recovered by precipitation stripping with a stoichiometric amount of oxalic acid. Nd2O3 and Dy2O3 were recovered with a purity of 99.87% and 99.94%, respectively. The feasibility to scale up this separation process was corroborated by a setup of mixer-settlers and highlighted by the possibility to fully recover and reuse the deep-eutectic solvent and the less polar phases employed in the extractions. The new proposed system based on a deep-eutectic solvent combined with traditional organic extraction phases presented higher selectivities and efficiencies than the analogous aqueous system. Extended X-ray absorption fine structure (EXAFS) was employed to elucidate the different mechanisms for extraction of Co and Fe from the deep-eutectic solvent and from an aqueous solution

    Engineering tyrosine-based electron flow pathways in proteins: The case of aplysia myoglobin

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    Tyrosine residues can act as redox cofactors that provide an electron transfer ("hole-hopping") route that enhances the rate of ferryl heme iron reduction by externally added reductants, for example, ascorbate. Aplysia fasciata myoglobin, having no naturally occurring tyrosines but 15 phenylalanines that can be selectively mutated to tyrosine residues, provides an ideal protein with which to study such through-protein electron transfer pathways and ways to manipulate them. Two surface exposed phenylalanines that are close to the heme have been mutated to tyrosines (F42Y, F98Y). In both of these, the rate of ferryl heme reduction increased by up to 3 orders of magnitude. This result cannot be explained in terms of distance or redox potential change between donor and acceptor but indicates that tyrosines, by virtue of their ability to form radicals, act as redox cofactors in a new pathway. The mechanism is discussed in terms of the Marcus theory and the specific protonation/deprotonation states of the oxoferryl iron and tyrosine. Tyrosine radicals have been observed and quantified by EPR spectroscopy in both mutants, consistent with the proposed mechanism. The location of each radical is unambiguous and allows us to validate theoretical methods that assign radical location on the basis of EPR hyperfine structure. Mutation to tyrosine decreases the lipid peroxidase activity of this myoglobin in the presence of low concentrations of reductant, and the possibility of decreasing the intrinsic toxicity of hemoglobin by introduction of these pathways is discussed. © 2012 American Chemical Society

    An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zw 1

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    We present an empirical template spectrum suitable for fitting/subtracting and studying the FeII and FeIII line emission in the restframe UV spectra of active galatic nuclei (AGNs), the first empirical UV iron template to cover the full 1250 - 3090 A range. Iron emission is often a severe contaminant in optical--UV spectra of AGNs. Its presence complicates and limits the accuracy of measurements of both strong and weak emission lines and the continuum emission, affecting studies of line and continuum interrelations, the ionization structure, and elemental abundances in AGNs. Despite the wealth of work on modeling the AGN FeII emission and the need to account for it in observed AGN spectra, there is no UV template electronically available to aid this process. The iron template we present is based on HST spectra of the Narrow Line Seyfert 1, IZw1. Its intrinsic narrow lines (~900 km/s) and rich iron spectrum make the template particularly suitable for use with most AGN spectra. The iron emission spectrum and the line identifications and measurements are presented and compared with the work of Laor et al. We illustrate the application of the derived FeII and FeIII templates by fitting and subtracting the iron emission from UV spectra of four high-z quasars and of the nearby quasar, 3C273. We briefly discuss the small discrepancies between this observed iron emission and the UV template, and compare the template with previously published ones. We discuss the advantages and limitations of the templates and of the template fitting method. We conclude that the templates work sufficiently well to be a valuable and important tool for eliminating and studying the iron emission in AGNs, at least until accurate theoretical iron emission models are developed. (Abridged)Comment: 73 pages including 7 figures, 6 tables. To appear in ApJS. Preprint is also available at http://www.astronomy.ohio-state.edu/~vester/IronEmission

    New ATLAS9 And MARCS Model Atmosphere Grids for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)

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    We present a new grid of model photospheres for the SDSS-III/APOGEE survey of stellar populations of the Galaxy, calculated using the ATLAS9 and MARCS codes. New opacity distribution functions were generated to calculate ATLAS9 model photospheres. MARCS models were calculated based on opacity sampling techniques. The metallicity ([M/H]) spans from -5 to 1.5 for ATLAS and -2.5 to 0.5 for MARCS models. There are three main differences with respect to previous ATLAS9 model grids: a new corrected H2O linelist, a wide range of carbon ([C/M]) and alpha element [alpha/M] variations, and solar reference abundances from Asplund et al. 2005. The added range of varying carbon and alpha element abundances also extends the previously calculated MARCS model grids. Altogether 1980 chemical compositions were used for the ATLAS9 grid, and 175 for the MARCS grid. Over 808 thousand ATLAS9 models were computed spanning temperatures from 3500K to 30000K and log g from 0 to 5, where larger temperatures only have high gravities. The MARCS models span from 3500K to 5500K, and log g from 0 to 5. All model atmospheres are publically available online.Comment: 8 pages, 6 figures, 5 tables, accepted for publication in The Astronomical Journa
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