68 research outputs found
Use of titanocalix[4]arenes in the ring opening polymerization of cyclic esters
Get PDFThe known dichloride complexes [TiCl2L(O)2(OR)2] (type I: R = Me (1), n-Pr (2) and n-pentyl (3); L(OH)2(OR)2 = 1,3-dialkyloxy-p-tert-butylcalix[4]arene), together with the new complexes {[TiL(O)3(OR)]2(μ-Cl)2}·6MeCN (R = n-decyl (4·6MeCN)), and [Ti(NCMe)Cl(L(O)3(OR))]·MeCN (type II: R = Me, 5·MeCN) are reported. Attempts to prepare type II for R = n-Pr and n-pentyl using [TiCl4] resulted in the complexes {[TiL(O)3(On-propyl)]2(μ-Cl)(μ-OH)} 6·7MeCN and {[TiL(O)3(On-pentyl)]2(μ-Cl)(μ-OH)}·7.5MeCN (7·7.5MeCN), respectively; use of [TiCl4(THF)2] resulted in a co-crystallized THF ring-opened product [Ti(NCMe)(μ3-O)L(O)4TiCl(O(CH2)4Cl)]2-2[TiCl(NCMe)(L(O)3(On-Pr))]·11MeCN (8·11MeCN). The molecular structures of 2·2MeCN, 4·6MeCN, and 5·MeCN together with the hydrolysis products {[TiL(O)3(OR)]2(μ-Cl)(μ-OH)} (R = n-Pr 6·7MeCN; n-pentyl, 7·7.5MeCN, 9·9MeCN); R = n-decyl 10·8.5MeCN) and that of the ring opened product 8·11MeCN and the co-crystallized species [Ti2(OH)Cl(L(O)3(OR))][L(OH)2(OR)2]·2.85(C2H3N)·0.43(H2O) (R = n-pentyl, 11·2.85(C2H3N)·0.43(H2O)) are reported. Type I and II complexes have been screened for their ability to act as catalysts in the ring opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL), δ-valerolactone (δ-VL), ω-pentadecalactone (ω-PDL) and rac-lactide (r-LA), both with and without benzyl alcohol present and either under N2 or in air. The copolymerization of ϵ-CL with δ-VL and with r-LA has also been investigated. For the ROP of ϵ-CL, all performed efficiently (>99% conversion) at 130 °C over 24 h both under N2 and in air, whilst over 1 h, for the type I complexes the trend was 3 > 2 > 1 but all were poor (≤12% conversion). By contrast, 5 over 1 h at 130 °C was highly active (85% conversion). At 80 °C, the activity trend followed the order 5 ≈ 4 > 3 > 2 > 1. For δ-VL, at 80 °C the activity trend 5 ≈ 4 > 1 > 2 > 3 was observed. ROP of the larger ω-PDL was only possible using 5 at 130 °C over 24 h with moderate activity (48% conversion). For r-LA, only low molecular weight products were obtained, whilst for the co-polymerization of ϵ-CL with δ-VL using 5, high activity was observed at 80 °C affording a polymer of molecular weight >23,000 Da and with equal incorporation of each monomer. In the case of ϵ-CL/r-LA co-polymerization using 5 either under N2 or air, the polymerization was more sluggish and only 65% conversion of CL was observed and the resultant co-polymer had 65:35 incorporation. Complex 5 could also be supported on silica, however this system was not as active as its homogeneous counterpart. Finally, the activity of these complexes is compared with that of three benchmark species: a di-phenolate Ti compound {TiCl2(2,2′-CH3CH[4,6-(t-Bu)2C6H2O]2)} (12) and a previously reported NO2-containing titanocalix[4]arene catalyst, namely cone-5,17-bis-tert-butyl-11,23-dinitro-25,27-dipropyloxy-26,28-dioxo-calix[4]arene titanium dichloride (13), as well as [Ti(Oi-Pr)4]; the parent calixarenes were also screened
Flexible planning in ravens?
Get PDFAcross two different contexts, Kabadayi and Osvath found that ravens preferentially selected items that could be used to obtain future rewards. Do these results demand a rethink of the evolution of flexible planning, or are there leaner alternative explanations for the performance of ravens
‘Neighbourhood is if they come out and talk to you’: Neighbourly connections and bonding social capital
No full text© The Author(s) 2017. Neighbourly relations have been theorised as ‘friendly distance’ in contrast to connections which are theorised as strong or intensive ties. The article explores the neighbourly relationships between residents of a peri-urban regional area outside Sydney in Australia. Strong interview themes emerged regarding the ways in which residents who were well connected within their locality talked about their neighbours, and this was in direct contrast to those living with a chronic condition – these people expressed a lack of connection with their neighbours. The major theme, ‘not in each other’s pockets’ reflects the negotiated nature of neighbour interactions, while the theme ‘neighbourhood is if they come out and talk to you’ speaks of isolation. The interactions of neighbours may in many cases constitute bonding capital as important weak or casual ties. These may not be available to the chronically ill or socially isolated or adequate without linking and bridging capital
Flexible planning in ravens?
No full textAcross two different contexts, Kabadayi and Osvath found that ravens preferentially selected items that could be used to obtain future rewards. Do these results demand a rethink of the evolution of flexible planning, or are there leaner alternative explanations for the performance of ravens
Telling Our Stories: Book Two
No full textCollection of stories by forty local writers describing family histories and anecdotes in the Grayson County, Texas area. Each story is preceded by a brief biographical sketch of the author
Creativity and flexibility in young children's use of external cognitive strategies.
No full textA cardinal feature of adult cognition is the awareness of our own cognitive struggles and the capacity to draw upon this awareness to offload internal demand into the environment. In this preregistered study conducted in Australia, we investigated whether 3-8-year-olds (N = 72, 36 male, 36 female, mostly White) could self-initiate such an external metacognitive strategy and transfer it across contexts. Children watched as an experimenter demonstrated how to mark the location of a hidden prize, thus helping them successfully retrieve that prize in the future. Children were then given the opportunity to spontaneously adopt an external marking strategy across six test trials. Children who did so at least once were then introduced to a conceptually similar but structurally distinct transfer task. Although most 3-year-olds deployed the demonstrated strategy in the initial test phase, none of them modified that strategy to solve the transfer task. By contrast, many children aged 4 years and older spontaneously devised more than one previously unseen reminder-setting strategy across the six transfer trials, with this tendency increasing with age. From age 6, children deployed effective external strategies on most trials, with the number, combination, and order of unique strategies used varying widely both within and across the older age groups. These results demonstrate young children's remarkable flexibility in the transferral of external strategies across contexts and point to pronounced individual differences in the strategies children devise. (PsycInfo Database Record (c) 2023 APA, all rights reserved).</p
Qualitative study of the clinician–parent interface in discussing prognosis following MRI and US imaging of preterm infants in the UK
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Health services research
Research
Qualitative study of the clinician–parent interface in discussing prognosis following MRI and US imaging of preterm infants in the UK
M E Harvey1,2,3, M E Redshaw2 On behalf of the ePrime Research Group
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Abstract
Objective To explore communication and interaction between parents and clinicians following neonatal ultrasound (US) and MRI of the brain of babies born preterm.
Setting This qualitative study was undertaken as part of a larger UK study of neonatal brain imaging. 511 infants were cared for in 14 London neonatal units with MR and cerebral US imaging in a specialist centre.
Participants Parents with infants born at <33 weeks gestation were randomised to receive prognostic information based on either MRI or US findings on their infants at term-corrected age.
Methods Discussions between parents and clinicians about the MRI or US result were audio recorded. Parents were told about the findings and their baby's predicted outcome. A topic guide ensured essential aspects were covered. Recordings were fully transcribed. Discussion of the scan results, the content and style of the interaction and parental response were analysed qualitatively in 36 recordings using NVivo V.10.
Outcomes Key themes and subthemes were identified in the clinician–parent discussions.
Results The overarching theme of ‘the communication interface’ was identified with three key themes: ‘giving information’, ‘managing the conversation’ and ‘getting it right’ and further subthemes. A range of approaches were used to facilitate parental understanding and engagement. There were differences in the exchanges when information about an abnormal scan was given. The overall structure of the discussions was largely similar, though the language used varied. In all of the discussions, the clinicians talked more than the parents.
Conclusions The discussions represent a difficult situation in which the challenge is to give and receive complex prognostic information in the context of considerable uncertainty. The study highlights the importance of being able to re-visit specific issues and any potential areas of misunderstanding, of making time to talk to parents appreciating their perspective and level of knowledge
The Birth Satisfaction Scale-Revised Indicator (BSS-RI)
Get PDF© 2017 The Author(s). Background: The current study sought to develop a short birth satisfaction indicator utilising items from the Birth Satisfaction Scale-Revised (BSS-R) for use as a brief measure of birth satisfaction and as a possible key performance indicator for perinatal service delivery evaluation. Building on the recently developed BSS-R, the study aimed to develop a simplified version of the instrument to assess birth satisfaction easily that could work as a short evaluative measure of clinical service delivery for labour and birth that is consistent with policy documents, placing women at the centre of the birth experience. Methods: The six item Birth Satisfaction Scale-Revised Indicator (BSS-RI) was embedded within the 2014 National Maternity Survey for England. A random selection of mothers who had given birth in a two week period in England were surveyed three months after the birth. Using a two-stage design and split-half dataset, exploratory factor analysis, confirmatory factor analysis, internal consistency, convergent, divergent and known-groups discriminant validity evaluation were conducted in a secondary analysis of the survey data. Results: Using this large population based survey of recent mothers the short revised measure was found to comprise two distinct domains of birth satisfaction, 'stress and emotional response to labour and birth' and 'quality of care'. The psychometric qualities of the tool were robust as were the indices of validity and reliability evaluated. Conclusion: The BSS-RI represents a short easily administered and scored measure of women's satisfaction with care and the experience of labou r and birth. The instrument is potentially useful for researchers, service evaluation and policy makers
Krein Support Vector Machine Classification of Antimicrobial Peptides
No full textAntimicrobial peptides (AMPs) represent a potential solution to the growing problem of antimicrobial resistance, yet their identification through wet-lab experiments is a costly and time-consuming process. Accurate computational predictions would allow rapid in silico screening of candidate AMPs, thereby accelerating the discovery process. Kernel methods are a class of machine learning algorithms that utilise a kernel function to transform input data into a new representation. When appropriately normalised, the kernel function can be regarded as a notion of similarity between instances. However, many expressive notions of similarity are not valid kernel functions, meaning they cannot be used with standard kernel methods such as the support-vector machine (SVM). The Kreın-SVM represents a generalisation of the standard SVM that admits a much larger class of similarity functions. In this study, we propose and develop Kreın-SVM models for AMP classification and prediction by employing the Levenshtein distance and local alignment score as sequence similarity functions. Utilising two datasets from the literature, each containing more than 3000 peptides, we train models to predict general antimicrobial activity. Our best models achieve an AUC of 0.967 and 0.863 on the test sets of each respective dataset, outperforming the in-house and literature baselines in both cases. We also curate a dataset of experimentally validated peptides, measured against Staphylococcus aureus and Pseudomonas aeruginosa, in order to evaluate the applicability of our methodology in predicting microbe-specific activity. In this case, our best models achieve an AUC of 0.933 and 0.917, respectively. Models to predict both general and microbe-specific activities are made available as web applications
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