2,550 research outputs found

    Post-translational insertion of boron in proteins to probe and modulate function

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    Boron is absent in proteins, yet is a micronutrient. It possesses unique bonding that could expand biological function including modes of Lewis acidity not available to typical elements of life. Here we show that post-translational Cβ–Bγ bond formation provides mild, direct, site-selective access to the minimally sized residue boronoalanine (Bal) in proteins. Precise anchoring of boron within complex biomolecular systems allows dative bond-mediated, site-dependent protein Lewis acid–base-pairing (LABP) by Bal. Dynamic protein-LABP creates tunable inter- and intramolecular ligand–host interactions, while reactive protein-LABP reveals reactively accessible sites through migratory boron-to-oxygen Cβ–Oγ covalent bond formation. These modes of dative bonding can also generate de novo function, such as control of thermo- and proteolytic stability in a target protein, or observation of transient structural features via chemical exchange. These results indicate that controlled insertion of boron facilitates stability modulation, structure determination, de novo binding activities and redox-responsive ‘mutation’

    Post-translational insertion of boron in proteins to probe and modulate function

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    Boron is absent in proteins, yet is a micronutrient. It possesses unique bonding that could expand biological function including modes of Lewis acidity not available to typical elements of life. Here we show that post-translational Cβ–Bγ bond formation provides mild, direct, site-selective access to the minimally sized residue boronoalanine (Bal) in proteins. Precise anchoring of boron within complex biomolecular systems allows dative bond-mediated, site-dependent protein Lewis acid–base-pairing (LABP) by Bal. Dynamic protein-LABP creates tunable inter- and intramolecular ligand–host interactions, while reactive protein-LABP reveals reactively accessible sites through migratory boron-to-oxygen Cβ–Oγ covalent bond formation. These modes of dative bonding can also generate de novo function, such as control of thermo- and proteolytic stability in a target protein, or observation of transient structural features via chemical exchange. These results indicate that controlled insertion of boron facilitates stability modulation, structure determination, de novo binding activities and redox-responsive ‘mutation’

    Correlation between measures of insulin resistance in fasting and non-fasting blood

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    <p>Abstract</p> <p>Background</p> <p>Epidemiological investigation of insulin resistance is difficult. Standard measures of insulin resistance require invasive investigations, which are impractical for large-scale studies. Surrogate measures using fasting blood samples have been developed, but even these are difficult to obtain in population-based studies. Measures of insulin resistance have not been validated in non-fasting blood samples. Our objective was to assess the correlations between fasting and non-fasting measures of insulin resistance/sensitivity.</p> <p>Methods</p> <p>Fasting and non-fasting measurements of metabolic function were compared in 30 volunteers (15 male) aged 28 to 48 years. Participants provided a morning blood sample after an overnight fast and a second sample approximately 4 hours after lunch on the same day.</p> <p>Results</p> <p>Non-fasting levels of the adipokines leptin, adiponectin, and leptin:adiponectin ratios were not significantly different and highly correlated with fasting values (r values 0.95, 0.96, and 0.95 respectively, P values < 0.001). There were moderate correlations between fasting and non-fasting estimates of insulin sensitivity using the McAuley (r = 0.60, P = 0.001) and QUICKI formulae (r = 0.39, P = 0.037). The HOMA-IR estimate of insulin resistance was also moderately correlated (r = 0.45, P = 0.016).</p> <p>Conclusions</p> <p>Semi-fasting measures of leptin, adiponectin, and leptin:adiponectin ratios correlate closely with fasting values and are likely to be sufficient for population-based research. Other measures of insulin resistance or sensitivity in semi-fasted blood samples are moderately correlated with values obtained after an overnight fast. These estimates of insulin resistance/sensitivity may also be adequate for many epidemiological studies and would avoid the difficulties of obtaining fasting blood samples.</p

    The effect of transmucosal 0.2mg/kg Midazolam premedication on dental anxiety, anaesthetic induction and psychological morbidity in children undergoing general anaesthesia for tooth extraction

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    &lt;b&gt;Background:&lt;/b&gt; The project aims were to evaluate the benefit of transmucosal Midazolam 0.2mg/kg pre-medication on anxiety, induction behaviour and psychological morbidity in children undergoing general anaesthesia (GA) extractions. &lt;b&gt;Method:&lt;/b&gt; 179 children aged 5-10 years (mean 6.53 years) participated in this randomised, double blind, placebo controlled trial. Ninety children had Midazolam placed in the buccal pouch. Dental anxiety was recorded pre operatively and 48 hours later using a child reported MCDAS-FIS scale. Behaviour at anaesthetic induction was recorded and psychological morbidity was scored by the parent using the Rutter Scale pre-operatively and again one-week later. Subsequent dental attendance was recorded at one, three and six months after GA. &lt;b&gt;Results:&lt;/b&gt; Whilst levels of mental anxiety did not reduce overall, the most anxious patients demonstrated a reduction in anxiety after receiving midazolam premedicationmay (p=0.01). Neither induction behaviour nor psychological morbidity improved. Irrespective of group, parents reported less hyperactive (p= 0.002) and more prosocial behaviour (p=0.002) after the procedure:;, older children improved most (p=0.048), Post GA Dental attendance was poor and unrelated to after the procedure and unaffected by premedication. &lt;b&gt;Conclusion:&lt;/b&gt; 0.2mg/kg buccal Midazolam provided some evidence for reducing anxiety in the most dentally anxious patients. However, induction behaviour, psychological morbidity and subsequent dental attendance were not found to alter between the premedication groups

    Rethinking media responsibility in the refugee ‘crisis’: a visual typology of European news

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    In this paper, we analyse how news images of the 2015 Syrian refugee ‘crisis’ visualise refugees and how, in so doing, they mobilise various forms of moral responsibility in ‘our’ mediated public life – various practical dispositions of action towards the misfortunes of migrants and refugees at Europe’s border. On the basis of empirical material from European news (June-December 2015), we construct a typology of visibilities of the ‘crisis’, each of which situates refugees within a different regime of visibility and claim to action: i) visibility as biological life, associated with monitorial action; ii) visibility as empathy associated with charitable action; iii) visibility as threat, associated with state security; iv) visibility as hospitality, associated with political activism; and v) visibility as selfreflexivity, associated with a post-humanitarian engagement with people like ‘us’. In conclusion, we argue that, important as these five categories of visibility are in introducing public dispositions to action towards the vulnerable, they nonetheless ultimately fail to humanise migrants and refugees. This failure to portray them as human beings with lives that are worth sharing should compel us, we urge, to radically re-think how we understand the media’s responsibility towards vulnerable others

    Are mice good models for human neuromuscular disease? Comparing muscle excursions in walking between mice and humans

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    The mouse is one of the most widely used animal models to study neuromuscular diseases and test new therapeutic strategies. However, findings from successful pre-clinical studies using mouse models frequently fail to translate to humans due to various factors. Differences in muscle function between the two species could be crucial but often have been overlooked. The purpose of this study was to evaluate and compare muscle excursions in walking between mice and humans

    Socio-cultural influences on the behaviour of South Asian women with diabetes in pregnancy: qualitative study using a multi-level theoretical approach

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    BACKGROUND: Diabetes in pregnancy is common in South Asians, especially those from low-income backgrounds, and leads to short-term morbidity and longer-term metabolic programming in mother and offspring. We sought to understand the multiple influences on behaviour (hence risks to metabolic health) of South Asian mothers and their unborn child, theorise how these influences interact and build over time, and inform the design of culturally congruent, multi-level interventions. METHODS: Our sample for this qualitative study was 45 women of Bangladeshi, Indian, Sri Lankan, or Pakistani origin aged 21-45 years with a history of diabetes in pregnancy, recruited from diabetes and antenatal services in two deprived London boroughs. Overall, 17 women shared their experiences of diabetes, pregnancy, and health services in group discussions and 28 women gave individual narrative interviews, facilitated by multilingual researchers, audiotaped, translated, and transcribed. Data were analysed using the constant comparative method, drawing on sociological and narrative theories. RESULTS: Key storylines (over-arching narratives) recurred across all ethnic groups studied. Short-term storylines depicted the experience of diabetic pregnancy as stressful, difficult to control, and associated with negative symptoms, especially tiredness. Taking exercise and restricting diet often worsened these symptoms and conflicted with advice from relatives and peers. Many women believed that exercise in pregnancy would damage the fetus and drain the mother's strength, and that eating would be strength-giving for mother and fetus. These short-term storylines were nested within medium-term storylines about family life, especially the cultural, practical, and material constraints of the traditional South Asian wife and mother role and past experiences of illness and healthcare, and within longer-term storylines about genetic, cultural, and material heritage - including migration, acculturation, and family memories of food insecurity. While peer advice was familiar, meaningful, and morally resonant, health education advice from clinicians was usually unfamiliar and devoid of cultural meaning. CONCLUSIONS: 'Behaviour change' interventions aimed at preventing and managing diabetes in South Asian women before and during pregnancy are likely to be ineffective if delivered in a socio-cultural vacuum. Individual education should be supplemented with community-level interventions to address the socio-material constraints and cultural frames within which behavioural 'choices' are made

    Body size modifies the relationship between maternal serum 25-hydroxyvitamin D concentrations and gestational diabetes in high-risk women

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    Obesity increases the risk of low 25-hydroxyvitamin D (25(OH) D) concentrations and gestational diabetes (GDM). We explored whether the association between GDM and change in 25(OH) D concentrations measured in the first (7-18 wk) and second (20-27 wk) trimesters of pregnancy is dependent on maternal BMI. The study was a prospective study of 219 women with BMI of >= 30 kg/m2, a history of GDM, or both. The participants were stratified by first-trimester BMI: BMI of = 35 kg/m(2). In the BMI group >= 35 kg/m(2), those who did not develop GDM during the follow-up showed higher increase in serum 25(OH) D concentrations compared with women who developed GDM (43.2 vs. 11.5%; P <0.001). No associations between 25(OH) D concentrations and GDM were observed in other BMI groups. These findings give an important aspect of the role of maternal body size in the association between vitamin D and GDM in high-risk women.Peer reviewe

    Study of Zγ events and limits on anomalous ZZγ and Zγγ couplings in pp̄ collisions at s=1.96TeV

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    We present a measurement of the Zγ production cross section and limits on anomalous ZZγ and Zγγ couplings for form-factor scales of Λ=750 and 1000 GeV. The measurement is based on 138 (152) candidates in the eeγ (μμγ) final state using 320(290)pb-1 of pp̄ collisions at s=1.96TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h10,30Z|<0.23, |h20,40Z|<0.020, |h10,30γ|<0.23, and |h20,40γ|<0.019 for Λ=1000GeV. © 2005 The American Physical Society

    Widespread platinum anomaly documented at theYounger Dryas onset in North American sedimentary sequences

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    Previously, a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger Dryas boundary (YDB) (12,800 Cal B.P.). In order to evaluate its geographic extent, fire-assay and inductively coupled plasma mass spectrometry (FA and ICP-MS) elemental analyses were performed on 11 widely separated archaeological bulk sedimentary sequences. We document discovery of a distinct Pt anomaly spread widely across North America and dating to the Younger Dryas (YD) onset. The apparent synchroneity of this widespread YDB Pt anomaly is consistent with Greenland Ice Sheet Project 2 (GISP2) data that indicated atmospheric input of platinum-rich dust. We expect the Pt anomaly to serve as a widely-distributed time marker horizon (datum) for identification and correlation of the onset of the YD climatic episode at 12,800 Cal B.P. This Pt datum will facilitate the dating and correlating of archaeological, paleontological, and paleoenvironmental data between sequences, especially those with limited age control
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