Photoreduction of outer membrane cytochromes: solution and proteoliposome nanocompartment studies

Due to ever increasing global energy demand and depletion of fossil fuels, interest has grown in developing systems which can utilise the near limitless supply of energy provided to the Earth by the sun. Artificial photosynthetic systems mimic natural photosynthesis by using photosensitisers that absorb solar energy to generate high-energy electrons. These photoexcited electrons are passed to catalysts which drive reductive transformations to produce fuels and valued organic compounds. Sacrificial electron donors regenerate photosensitisers to complete the photocatalytic cycle. To date artificial photosynthetic systems are unable to fully mimic and reap the full benefits of natural photosynthesis as they lack spatially separating reaction compartments, and/or compartment-linking transmembrane electron transport chains. A model for the biochemistry that supports such transmembrane electron transfer is provided by the outer membrane cytochromes of Shewanella oneidensis MR-1. In this Gram-negative bacterium, trans-outermembrane electron transfer to extracellular electron acceptors is performed by the extracellular cytochromes MtrC and OmcA acting together with the porin:cytochrome complex (MtrCAB), which provides an outer membrane spanning conduit that moves electrons from the periplasm to the cell surface. Liposomes offer reaction compartments which are separated from the surrounding external environment by a phospholipid membrane. Incorporation of MtrCAB in the membranes of liposomes containing methyl viologen facilitates transmembrane electron transfer from an external reductant to the compartmentalised electron acceptor. In this study the potential for MtrCAB proteoliposomes to act as a modular artificial photosynthetic system, which performs reductive transformations, was investigated. To explore this potential we have studied the ability of several photosensitisers to photoreduce: i) outer membrane cytochromes of S. oneidensis; ii) methyl viologen in solution and within liposomes; iii) MtrCAB in liposome membranes; and iv) reactive red 120 in solution and within (proteo)liposomes. In addition the sacrificial electron donor(s), photoreduction mechanisms and interaction mechanisms used by each photosensitiser have been identified

The role of emotion regulation in the relationship between mindfulness and risk factors for disordered eating: A longitudinal mediation analysis

Objective: Evidence suggests mindfulness may reduce risk factors for disordered eating. However, mechanisms of change in this relationship are unclear. This longitudinal study tested whether emotion regulation mediates the prospective associations between mindfulness and two proximal risk factors for disordered eating: weight and shape concerns, and negative affect. Method: This study is a secondary analysis of data collected within an eating disorder prevention trial. Adolescent girls (N = 374, M age = 15.70, SD = 0.77) completed self-report measures of mindfulness, emotion regulation, weight and shape concerns, and negative affect at baseline, 2 months following baseline, and 7 months following baseline. Path analyses were computed to test hypothesized indirect effects using confidence intervals based on 5000 bootstrap samples. Results: Higher baseline mindfulness predicted lower weight and shape concerns and negative affect at 7 months via a mediator of better emotion regulation at 2 months. This effect remained while controlling for earlier measurements of the mediator and outcome in the model of negative affect but not weight and shape concerns. Discussion: Emotion regulation may be an important mechanism explaining how mindfulness influences negative affect. Efforts should be made to intervene on mindfulness and emotion regulation in prevention and early intervention programmes for eating disorders and other psychiatric conditions. Public Significance: Research has shown that mindfulness can help to reduce some of the risk of developing an eating disorder. This study explored whether mindfulness reduces some of this risk by helping people to better manage their emotions. Understanding this process can help us to develop better mindfulness-based strategies to support people who are at risk of developing an eating disorder.</p

Impact of personal alcohol consumption on aspects of medical student alcohol-related competencies

AimAs part of the prevention and management of alcohol-related harms, health professionals need to be competent to assess the level of alcohol use in patients. In this study, we explored how medical students’ own alcohol consumption impacts on their familiarity with alcohol brands, strengths and alcohol-related harms.MethodsAs part of a wider study investigating the concept of ‘alcohol health literacy’, this study combined an anonymous online survey, linked to an electronic alcohol ‘brand’ recognition game. Participants were medical students in their first clinical year. The survey recorded demographics, self-reported alcohol consumption (using the AUDIT-C), a visual test of relative alcohol concentrations of wine, beer and spirits, and a free-text response asking them to list alcohol-related harms. Participants then completed the brand recognition game recording accuracy and reaction time for identifying alcohol drink brands.ResultsOne hundred and fifty students participated. There was a significant effect of ethnicity on drinking status, with 48% of non-white participants scoring zero on the AUDIT-C. Students who reported any alcohol consumption were more likely to correctly assess relative alcohol concentrations and were faster and more accurate at recognizing alcohol brands, which was dose dependent. Overall, only 45% correctly recognized relative alcohol strengths of drinks presented.ConclusionsAmong third-year medical students, ability to correctly identify relative strengths of alcoholic drinks is low. As might be expected, students who drink alcohol tend to identify brands and strengths more accurately. This has implications for how best to tailor the delivery of teaching and training about alcohol to ensure similar levels of clinical confidence in dealing with future patients regardless of personal experience

Experiences of using digital mindfulness-based interventions: Rapid scoping review and thematic synthesis

Background: Digital mindfulness-based interventions (MBIs) are a promising approach to deliver accessible and scalable mindfulness training and have been shown to improve a range of health outcomes. However, the success of digital MBIs is reliant on adequate engagement, which remains a crucial challenge. Understanding people’s experiences of using digital MBIs and identifying the core factors that facilitate or act as barriers to engagement is essential to inform intervention development and maximize engagement and outcomes. Objective: This study aims to systematically map the literature on people’s experiences of using digital MBIs that target psychosocial variables (eg, anxiety, depression, distress, and well-being) and identify key barriers to and facilitators of engagement. Methods: We conducted a scoping review to synthesize empirical qualitative research on people’s experiences of using digital MBIs. We adopted a streamlined approach to ensure that the evidence could be incorporated into the early stages of intervention development. The search strategy identified articles with at least one keyword related to mindfulness, digital, user experience, and psychosocial variables in their title or abstract. Inclusion criteria specified that articles must have a qualitative component, report on participants’ experiences of using a digital MBI designed to improve psychosocial variables, and have a sample age range that at least partially overlapped with 16 to 35 years. Qualitative data on user experience were charted and analyzed using inductive thematic synthesis to generate understandings that go beyond the content of the original studies. We used the Quality of Reporting Tool to critically appraise the included sources of evidence. Results: The search identified 510 studies, 22 (4.3%) of which met the inclusion criteria. Overall, the samples were approximately 78% female and 79% White; participants were aged between 16 and 69 years; and the most used measures in intervention studies were mindfulness, psychological flexibility, and variables related to mental health (including depression, anxiety, stress, and well-being). All studies were judged to be adequately reported. We identified 3 themes characterizing barriers to and facilitators of engagement: responses to own practice (ie, negative reactions to one’s own practice are common and can deplete motivation), making mindfulness a habit (ie, creating a consistent training routine is essential yet challenging), and leaning on others (ie, those engaging depend on someone else for support). Conclusions: The themes identified in this review provide crucial insights as to why people frequently stop engaging with digital MBIs. Researchers and developers should consider using person-based coparticipatory methods to improve acceptability of and engagement with digital MBIs, increase their effectiveness, and support their translation to real-world use. Such strategies must be grounded in relevant literature and meet the priorities and needs of the individuals who will use the interventions

Testing self-report time-use diaries against objective instruments in real time

This study provides a new test of time-use diary methodology, comparing diaries with a pair of objective criterion measures: wearable cameras and accelerometers. A volunteer sample of respondents (n = 148) completed conventional self-report paper time-use diaries using the standard UK Harmonised European Time Use Study (HETUS) instrument. On the diary day, respondents wore a camera that continuously recorded images of their activities during waking hours (approximately 1,500–2,000 images/day) and also an accelerometer that tracked their physical activity continuously throughout the 24-hour period covered by the diary. Of the initial 148 participants recruited, 131 returned usable diary and camera records, of whom 124 also provided a usable whole-day accelerometer record. The comparison of the diary data with the camera and accelerometer records strongly supports the use of diary methodology at both the aggregate (sample) and individual levels. It provides evidence that time-use data could be used to complement physical activity questionnaires for providing population-level estimates of physical activity. It also implies new opportunities for investigating techniques for calibrating metabolic equivalent of task (MET) attributions to daily activities using large-scale, population-representative time-use diary studies

Integrating mobile-phone based assessment for psychosis into people\u27s everyday lives and clinical care: a qualitative study

Background: Over the past decade policy makers have emphasised the importance of healthcare technology in the management of long-term conditions. Mobile-phone based assessment may be one method of facilitating clinically- and cost-effective intervention, and increasing the autonomy and independence of service users. Recently, text-message and smartphone interfaces have been developed for the real-time assessment of symptoms in individuals with schizophrenia. Little is currently understood about patients\u27 perceptions of these systems, and how they might be implemented into their everyday routine and clinical care. Method: 24 community based individuals with non-affective psychosis completed a randomised repeated-measure cross-over design study, where they filled in self-report questions about their symptoms via text-messages on their own phone, or via a purpose designed software application for Android smartphones, for six days. Qualitative interviews were conducted in order to explore participants\u27 perceptions and experiences of the devices, and thematic analysis was used to analyse the data. Results: Three themes emerged from the data: i) the appeal of usability and familiarity, ii) acceptability, validity and integration into domestic routines, and iii) perceived impact on clinical care. Although participants generally found the technology non-stigmatising and well integrated into their everyday activities, the repetitiveness of the questions was identified as a likely barrier to long-term adoption. Potential benefits to the quality of care received were seen in terms of assisting clinicians, faster and more efficient data exchange, and aiding patient-clinician communication. However, patients often failed to see the relevance of the systems to their personal situations, and emphasised the threat to the person centred element of their care. Conclusions: The feedback presented in this paper suggests that patients are conscious of the benefits that mobile-phone based assessment could bring to clinical care, and that the technology can be successfully integrated into everyday routine. However, it also suggests that it is important to demonstrate to patients the personal, as well as theoretical, benefits of the technology. In the future it will be important to establish whether clinical practitioners are able to use this technology as part of a personalised mental health regime

Photoreduction of Shewanella oneidensis Extracellular Cytochromes by Organic Chromophores and Dye-Sensitized TiO2.

The transfer of photoenergized electrons from extracellular photosensitizers across a bacterial cell envelope to drive intracellular chemical transformations represents an attractive way to harness nature's catalytic machinery for solar-assisted chemical synthesis. In $\textit{Shewanella oneidensis}$ MR-1 (MR-1), trans-outer-membrane electron transfer is performed by the extracellular cytochromes MtrC and OmcA acting together with the outer-membrane-spanning porin$\cdot$cytochrome complex (MtrAB). Here we demonstrate photoreduction of solutions of MtrC, OmcA, and the MtrCAB complex by soluble photosensitizers: namely, eosin Y, fluorescein, proflavine, flavin, and adenine dinucleotide, as well as by riboflavin and flavin mononucleotide, two compounds secreted by MR-1. We show photoreduction of MtrC and OmcA adsorbed on Ru$^{\text{II}}$-dye-sensitized TiO$_2$ nanoparticles and that these protein-coated particles perform photocatalytic reduction of solutions of MtrC, OmcA, and MtrCAB. These findings provide a framework for informed development of strategies for using the outer-membrane-associated cytochromes of MR-1 for solar-driven microbial synthesis in natural and engineered bacteria.This work was supported by the UK Biotechnology and Biological Sciences Research Council (grants BB/K009753/1, BB/K010220/1, BB/K009885/1, and BB/K00929X/1), the Engineering and Physical Sciences Research Council (EP/M001989/1, PhD studentship 1307196 to E.V.A.), a Royal Society Leverhulme Trust Senior Research Fellowship to J.N.B., the Christian Doppler Research Association, and OMV group

A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes.

In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.This work was supported by the BBSRC (grants BB/K009753/1, BB/K010220/1, and BB/K009885/1), the EPSRC (EP/H00338X/2; PhD studentship to Emma Ainsworth), the Christian Doppler Research Association and the OMV Group. The authors appreciate Dr. Liang Shi (PNNL) and Dr. Marcus Edwards (UEA) for providing the S. oneidensis strain and the protocol allowing for purification of MtrC.This is the final published version of the article. It was originally published in Advanced Functional Materials (Hwang ET, Sheikh K, Orchard KL, Hojo D, Radu V, Lee C-Y, Ainsworth E, Lockwood C, Gross MA, Adschiri T, Reisner E, Butt JN, Jeuken LJC, Advanced Functional Materials 2015, 25, 2308–2315, doi: 10.1002/adfm.201404541) http://dx.doi.org/10.1002/adfm.201404541

The theory of planned behaviour predicts self-reports of walking, but does not predict step count

Objectives This paper compares multiple measures of walking in two studies, and the second study compares how well Theory of Planned Behaviour (TPB) constructs perform in predicting these different measures. Methods In Study 1, 41 participants wore a New Lifestyles NL-2000 pedometer for 1 week. Subsequently, participants completed a questionnaire containing measures of the TPB constructs and two self-report measures of walking, followed by two interview measures of walking. For Study 2, 200 RAF trainee aircraftsmen wore pedometers for 2 weeks. At the end of each week, participants completed the questionnaire and interview measures of walking. Results Both studies found no significant association between questionnaire measures of walking and pedometer measures. In Study 1, the interview measures produced significant, large correlations with the pedometer measure, but these relationships were markedly weaker in the second study. TPB variables were found to explain 22% of variance in intention to walk in Study 1 and 45% of the variance in Study 2. In Study 2, prediction of subsequent measures of behaviour was found to be weak, except when using a single-item measure of walking. Conclusions Recall of walking is poor, and accurate measurement by self-report is problematic. Although the TPB predicts intentions to walk well, it does not predict actual amount of walking, as assessed by pedometer. Possible reasons for these findings include the unique nature of walking as an activity primarily used to facilitate higher order goals. The use of single-item measures may exaggerate the effectiveness of the TPB model for walking, and possibly other forms of physical activity.</p