1,028 research outputs found

    Ground-state Spectrum of Light-quark Mesons

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    A confining, Goldstone theorem preserving, separable Ansatz for the ladder kernel of the two-body Bethe-Salpeter equation is constructed from phenomenologically efficacious uu, dd and ss dressed-quark propagators. The simplicity of the approach is its merit. It provides a good description of the ground-state isovector-pseudoscalar, vector and axial-vector meson spectrum; facilitates an exploration of the relative importance of various components of the two-body Bethe-Salpeter amplitudes, showing that sub-leading Dirac components are quantitatively important in the isovector-pseudoscalar meson channels; and allows a scrutiny of the domain of applicability of ladder truncation studies. A colour-antitriplet diquark spectrum is obtained. Shortcomings of separable Ans\"atze and the ladder kernel are highlighted.Comment: 30 pages, LaTeX/REVTEX 3.0, no figure

    Influence of the Spatial Distribution of Cationic Functional Groups at Nanoparticle Surfaces on Bacterial Viability and Membrane Interactions

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    While positively charged nanomaterials induce cytotoxicity in many organisms, much less is known about how the spatial distribution and presentation of molecular surface charge impact nanoparticle–biological interactions. We systematically functionalized diamond nanoparticle surfaces with five different cationic surface molecules having different molecular structures and conformations, including four small ligands and one polymer, and we then probed the molecular-level interaction between these nanoparticles and bacterial cells. Shewanella oneidensis MR-1 was used as a model bacterial cell system to investigate how the molecular length and conformation of cationic surface charges influence their interactions with the Gram-negative bacterial membranes. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) demonstrate the covalent modification of the nanoparticle surface with the desired cationic organic monolayers. Surprisingly, bacterial growth-based viability (GBV) and membrane damage assays both show only minimal biological impact by the NPs functionalized with short cationic ligands within the concentration range tested, yet NPs covalently linked to a cationic polymer induce strong cytotoxicity, including reduced cellular viability and significant membrane damage at the same concentration of cationic groups. Transmission electron microscopy (TEM) images of these NP-exposed bacterial cells show that NPs functionalized with cationic polymers induce significant membrane distortion and the production of outer membrane vesicle-like features, while NPs bearing short cationic ligands only exhibit weak membrane association. Our results demonstrate that the spatial distribution of molecular charge plays a key role in controlling the interaction of cationic nanoparticles with bacterial cell membranes and the subsequent biological impact. Nanoparticles functionalized with ligands having different lengths and conformations can have large differences in interactions even while having nearly identical zeta potentials. While the zeta potential is a convenient and commonly used measure of nanoparticle charge, it does not capture essential differences in molecular-level nanoparticle properties that control their biological impact

    Feeling our way: academia, emotions and a politics of care

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    This paper aims to better understand the role of emotions in academia, and their part in producing, and challenging, an increasingly normalized neoliberal academy. It unfolds from two narratives that foreground emotions in and across academic spaces and practices, to critically explore how knowledges and positions are constructed and circulated. It then moves to consider these issues through the lens of care as a political stance towards being and becoming academics in neoliberal times. Our aim is to contribute to the burgeoning literature on emotional geographies, explicitly bringing this work into conversation with resurgent debates surrounding an ethic of care, as part of a politic of critiquing individualism and managerialism in (and beyond) the academy. We consider the ways in which neoliberal university structures circulate particular affects, prompting emotions such as desire and anxiety, and the internalisation of competition and audit as embodied scholars. Our narratives exemplify how attendant emotions and affect can reverberate and be further reproduced through university cultures, and diffuse across personal and professional lives. We argue that emotions in academia matter, mutually co-producing everyday social relations and practices at and across all levels. We are interested in their political implications, and how neoliberal norms can be shifted through practices of caring-with

    Is a combination of varenicline and nicotine patch more effective in helping smokers quit than varenicline alone? A randomised controlled trial

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Caregiver perceptions and experiences of paediatric emergency department attendance during the COVID-19 pandemic: a mixed-methods study

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    BACKGROUND: During the early stages of the COVID-19 pandemic, concerns were raised about reduced attendance at hospitals, particularly in paediatric emergency departments, which could result in preventable poorer outcomes and late presentations among children requiring emergency care. We aimed to investigate the impact of COVID-19 on health-seeking behaviour and decision-making processes of caregivers presenting to paediatric emergency services at a National Health Service (NHS) Trust in London. MATERIALS AND METHODS: We conducted a mixed-methods study (survey and semi-structured interviews) across two hospital sites between November-December 2020. Data from each study were collected concurrently followed by data comparison. RESULTS: Overall, 100 caregivers participated in our study; 80 completed the survey only, two completed the interview only and 18 completed both. Our quantitative study found that almost two-thirds (63%, n = 62) of caregivers attended the department within two days of their child becoming ill. Our qualitative study identified three major themes which were underpinned by concepts of trust, safety and uncertainty and were assessed in relation to the temporal nature of the pandemic and the caregivers' journey to care. We found most caregivers balanced their concerns of COVID-19 and a perceived "overwhelmed" NHS by speaking to trusted sources, predominantly general practitioners (GPs). CONCLUSION: Caregivers have adapted their health-seeking behaviour throughout the pandemic as new information and guidance have been released. We identified several factors affecting decisions to attend; some existed before the pandemic (e.g., concerns for child's health) whilst others were due to the pandemic (e.g., perceived risks of transmission when accessing healthcare services). We recommend trusted medical professionals, particularly GPs, continue to provide reassurance to caregivers to seek emergency paediatric care when required. Communicating the hospital safety procedures and the importance of early intervention to caregivers could additionally provide reassurance to those concerned about the risks of accessing the hospital environment

    Understanding decisions to use e-cigarettes or behavioural support to quit tobacco: a qualitative study of current and ex-smokers and stop smoking service staff.

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    AIM: To examine factors influencing current and ex-smokers' decisions to use e-cigarettes or behavioural support, including potential impacts of any differences in perspectives between smokers and their local stop smoking services (SSSs). DESIGN: Semi-structured qualitative interviews followed by framework analysis, with the 'capability', 'opportunity', 'motivation' and 'behaviour' (COM-B) model of behaviour change used to frame findings. SETTING: SSSs and surrounding local areas in England. PARTICIPANTS: Interviewees (n = 46) were current or recent smokers (n = 29) and SSS staff or stakeholders (n = 17). MEASUREMENTS: Interview topic guides explored influences on smokers' choice of quit method and characteristics of support offered by local SSSs. FINDINGS: Current and ex-smokers showed a range of views on potential risks from long-term vaping, which appeared to be particularly relevant for the capability dimension of COM-B. These different attitudes to vaping appeared to be linked to variations in people's perceived capability to assess evidence around e-cigarettes' safety. Motivations for using or avoiding e-cigarettes and SSSs often appeared to overlap: attitudes to both e-cigarettes and nicotine replacement therapy from SSSs often reflected personal experiences and views on whether switching from smoking to these alternatives represented successful quitting or simply ongoing nicotine addiction. For smokers, opportunities to use e-cigarettes or SSSs appeared to be largely determined by perceived time requirements. Furthermore, interviews with SSS professionals suggested that opportunities to access SSSs for ex-smokers who were now regular vapers may be being influenced by different e-cigarette policies adopted in individual areas. CONCLUSIONS: In England, smokers' decisions to use e-cigarettes and local stop smoking services appear to be determined by varied influences across the COM-B framework. Both smokers and stop smoking service professionals display diverse views about potential risks from e-cigarettes, which has relevance for the provision of behavioural support as well as the uptake of vaping

    Regular breakfast consumption and type 2 diabetes risk markers in 9- to 10-year-old children in the child heart and health study in England (CHASE): a cross-sectional analysis.

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    BACKGROUND: Regular breakfast consumption may protect against type 2 diabetes risk in adults but little is known about its influence on type 2 diabetes risk markers in children. We investigated the associations between breakfast consumption (frequency and content) and risk markers for type 2 diabetes (particularly insulin resistance and glycaemia) and cardiovascular disease in children. METHODS AND FINDINGS: We conducted a cross-sectional study of 4,116 UK primary school children aged 9-10 years. Participants provided information on breakfast frequency, had measurements of body composition, and gave fasting blood samples for measurements of blood lipids, insulin, glucose, and glycated haemoglobin (HbA1c). A subgroup of 2,004 children also completed a 24-hour dietary recall. Among 4,116 children studied, 3,056 (74%) ate breakfast daily, 450 (11%) most days, 372 (9%) some days, and 238 (6%) not usually. Graded associations between breakfast frequency and risk markers were observed; children who reported not usually having breakfast had higher fasting insulin (percent difference 26.4%, 95% CI 16.6%-37.0%), insulin resistance (percent difference 26.7%, 95% CI 17.0%-37.2%), HbA1c (percent difference 1.2%, 95% CI 0.4%-2.0%), glucose (percent difference 1.0%, 95% CI 0.0%-2.0%), and urate (percent difference 6%, 95% CI 3%-10%) than those who reported having breakfast daily; these differences were little affected by adjustment for adiposity, socioeconomic status, and physical activity levels. When the higher levels of triglyceride, systolic blood pressure, and C-reactive protein for those who usually did not eat breakfast relative to those who ate breakfast daily were adjusted for adiposity, the differences were no longer significant. Children eating a high fibre cereal breakfast had lower insulin resistance than those eating other breakfast types (p for heterogeneity <0.01). Differences in nutrient intakes between breakfast frequency groups did not account for the differences in type 2 diabetes markers. CONCLUSIONS: Children who ate breakfast daily, particularly a high fibre cereal breakfast, had a more favourable type 2 diabetes risk profile. Trials are needed to quantify the protective effect of breakfast on emerging type 2 diabetes risk. Please see later in the article for the Editors' Summary

    The effectiveness of interventions to change six health behaviours: a review of reviews

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    Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency). Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis. Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities. Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p

    The gray matter volume of the amygdala is correlated with the perception of melodic intervals: a voxel-based morphometry study

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    Music is not simply a series of organized pitches, rhythms, and timbres, it is capable of evoking emotions. In the present study, voxel-based morphometry (VBM) was employed to explore the neural basis that may link music to emotion. To do this, we identified the neuroanatomical correlates of the ability to extract pitch interval size in a music segment (i.e., interval perception) in a large population of healthy young adults (N = 264). Behaviorally, we found that interval perception was correlated with daily emotional experiences, indicating the intrinsic link between music and emotion. Neurally, and as expected, we found that interval perception was positively correlated with the gray matter volume (GMV) of the bilateral temporal cortex. More important, a larger GMV of the bilateral amygdala was associated with better interval perception, suggesting that the amygdala, which is the neural substrate of emotional processing, is also involved in music processing. In sum, our study provides one of first neuroanatomical evidence on the association between the amygdala and music, which contributes to our understanding of exactly how music evokes emotional responses
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