592 research outputs found

    Self-assembly around curved surfaces

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    We present a parametric study of self-assembled photonic crystal growth as a function of radius of curvature. To do this, we used a combination of microscope slides, glass capillaries and optical fibres as substrates to grow the self-assembled films on. Microscope and SEM images, as well as broadband transmission spectra were used to characterise the crystal, and the effect the changing surface curvature had on the crystal quality. Limitations for fabricating the crystals on highly curved surfaces will be presented

    Diet quality in late midlife is associated with faster walking speed in later life in women, but not men: findings from a prospective British birth cohort

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    Healthy diet has been linked to better age-related physical functioning, but evidence on the relationship of overall diet quality in late midlife and clinically relevant measures of physical functioning in later life is limited. Research on potential sex differences in this relationship is scarce. The aim was to investigate the prospective association between overall diet quality, as assessed by the Healthy Eating Index-2015 at age 60-64y and measures of walking speed seven years later, among men and women from the Insight46, a neuroscience sub-study of the Medical Research Council National Survey of Health and Development. Diet was assessed at age 60-64y using five-day food diaries, from which total HEI-2015 was calculated. At age 69-71y, walking speed was estimated during four 10-meter walks at self-selected pace, using inertial measurement units. Multivariable linear regression models with sex as modifier, controlling for age, follow-up, lifestyle, health, social variables and physical performance were used. The final sample was 164 women and 167 men (n=331). Women had higher HEI-2015 scores and slower walking speed than men. A 10 point increase in HEI-2015 was associated with faster walking speed seven years later among women (B: 0.024, 95% CI: 0.006, 0.043), but not men. The association remained significant in the multivariable model (B: 0.021, 95% CI: 0.003, 0.040). In women in late midlife higher diet quality is associated with faster walking speed. A healthy diet in late midlife is likely to contribute towards better age-related physical capability and sex differences are likely to affect this relationship

    Practical implementation, characterization and applications of a multi-colour time-gated luminescence microscope

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    Time-gated luminescence microscopy using long-lifetime molecular probes can effectively eliminate autofluorescence to enable high contrast imaging. Here we investigate a new strategy of time-gated imaging for simultaneous visualisation of multiple species of microorganisms stained with long-lived complexes under low-background conditions. This is realized by imaging two pathogenic organisms (Giardia lamblia stained with a red europium probe and Cryptosporidium parvum with a green terbium probe) at UV wavelengths (320-400 nm) through synchronization of a flash lamp with high repetition rate (1 kHz) to a robust time-gating detection unit. This approach provides four times enhancement in signal-to-background ratio over non-time-gated imaging, while the average signal intensity also increases six-fold compared with that under UV LED excitation. The high sensitivity is further confirmed by imaging the single europium-doped Y2O2S nanocrystals (150 nm). We report technical details regarding the time-gating detection unit and demonstrate its compatibility with commercial epi-fluorescence microscopes, providing a valuable and convenient addition to standard laboratory equipment

    Dynamical Autler-Townes control of a phase qubit

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    Routers, switches, and repeaters are essential components of modern information-processing systems. Similar devices will be needed in future superconducting quantum computers. In this work we investigate experimentally the time evolution of Autler-Townes splitting in a superconducting phase qubit under the application of a control tone resonantly coupled to the second transition. A three-level model that includes independently determined parameters for relaxation and dephasing gives excellent agreement with the experiment. The results demonstrate that the qubit can be used as a ON/OFF switch with 100 ns operating time-scale for the reflection/transmission of photons coming from an applied probe microwave tone. The ON state is realized when the control tone is sufficiently strong to generate an Autler-Townes doublet, suppressing the absorption of the probe tone photons and resulting in a maximum of transmission.Comment: 8 pages, 8 figure

    Trk receptor signaling and sensory neuron fate are perturbed in human neuropathy caused by Gars mutations

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    Charcot-Marie-Tooth disease type 2D (CMT2D) is a peripheral nerve disorder caused by dominant, toxic, gain-of-function mutations in the widely expressed, housekeeping gene, GARS. The mechanisms underlying selective nerve pathology in CMT2D remain unresolved, as does the cause of the mild-to-moderate sensory involvement that distinguishes CMT2D from the allelic disorder distal spinal muscular atrophy type V. To elucidate the mechanism responsible for the underlying afferent nerve pathology, we examined the sensory nervous system of CMT2D mice. We show that the equilibrium between functional subtypes of sensory neuron in dorsal root ganglia is distorted by Gars mutations, leading to sensory defects in peripheral tissues and correlating with overall disease severity. CMT2D mice display changes in sensory behaviour concordant with the afferent imbalance, which is present at birth and non-progressive, indicating that sensory neuron identity is pre-natally perturbed and that a critical developmental insult is key to the afferent pathology. Through in vitro experiments, mutant, but not wild-type, GlyRS was shown to aberrantly interact with the Trk receptors and cause mis-activation of Trk signalling, which is essential for sensory neuron differentiation and development. Together, this work suggests that both neurodevelopmental and neurodegenerative mechanisms contribute to CMT2D pathogenesis, and thus has profound implications for the timing of future therapeutic treatments

    Quantitative effects of tobacco smoking exposure on the maternal-fetal circulation

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    <p>Abstract</p> <p>Background</p> <p>Despite the existence of various published studies regarding the effects of tobacco smoking on pregnancy, and especially in regards to placental blood flow and vascular resistance, some points still require clarification. In addition, the amount of damage due to tobacco smoking exposure that occurs has not been quantified by objective means. In this study, we looked for a possible association between flow resistance indices of several arteries and the levels of urinary cotinine and the concentration of carbon monoxide in the exhaled air (COex) of both smoking and non-smoking pregnant women. We also looked for a relationship between those findings and fetal growth and birth weight.</p> <p>Methods</p> <p>In a prospective design, thirty pregnant smokers and thirty-four pregnant non-smokers were studied. The volunteers signed consent forms, completed a self-applied questionnaire and were subjected to Doppler velocimetry. Tobacco smoking exposure was quantified by subject provided information and confirmed by the measurement of urinary cotinine levels and by the concentration of carbon monoxide in the exhaled air (COex). The weight of newborns was evaluated immediately after birth.</p> <p>Results</p> <p>Comparing smoking to non-smoking pregnant women, a significant increase in the resistance index was observed in the uterine arteries (P = 0.001) and umbilical artery (P = 0.001), and a decrease in the middle cerebral artery (P = 0.450). These findings were associated with progressively higher concentrations of COex and urinary cotinine. A decrease in the birth weight was also detected (P < 0.001) in association with a progressive increase in the tobacco exposure of the pregnant woman.</p> <p>Conclusions</p> <p>In pregnant women who smoke, higher arterial resistance indices and lower birth weights were observed, and these findings were associated with increasing levels of tobacco smoking exposure. The values were significantly different when compared to those found in non-smoking pregnant women. This study contributes to the findings that smoking damage during pregnancy is dose-dependent, as demonstrated by the objective methods for measuring tobacco smoking exposure.</p

    What do evidence-based secondary journals tell us about the publication of clinically important articles in primary healthcare journals?

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    BACKGROUND: We conducted this analysis to determine i) which journals publish high-quality, clinically relevant studies in internal medicine, general/family practice, general practice nursing, and mental health; and ii) the proportion of clinically relevant articles in each journal. METHODS: We performed an analytic survey of a hand search of 170 general medicine, general healthcare, and specialty journals for 2000. Research staff assessed individual articles by using explicit criteria for scientific merit for healthcare application. Practitioners assessed the clinical importance of these articles. Outcome measures were the number of high-quality, clinically relevant studies published in the 170 journal titles and how many of these were published in each of four discipline-specific, secondary "evidence-based" journals (ACP Journal Club for internal medicine and its subspecialties; Evidence-Based Medicine for general/family practice; Evidence-Based Nursing for general practice nursing; and Evidence-Based Mental Health for all aspects of mental health). Original studies and review articles were classified for purpose: therapy and prevention, screening and diagnosis, prognosis, etiology and harm, economics and cost, clinical prediction guides, and qualitative studies. RESULTS: We evaluated 60,352 articles from 170 journal titles. The pass criteria of high-quality methods and clinically relevant material were met by 3059 original articles and 1073 review articles. For ACP Journal Club (internal medicine), four titles supplied 56.5% of the articles and 27 titles supplied the other 43.5%. For Evidence-Based Medicine (general/family practice), five titles supplied 50.7% of the articles and 40 titles supplied the remaining 49.3%. For Evidence-Based Nursing (general practice nursing), seven titles supplied 51.0% of the articles and 34 additional titles supplied 49.0%. For Evidence-Based Mental Health (mental health), nine titles supplied 53.2% of the articles and 34 additional titles supplied 46.8%. For the disciplines of internal medicine, general/family practice, and mental health (but not general practice nursing), the number of clinically important articles was correlated withScience Citation Index (SCI) Impact Factors. CONCLUSIONS: Although many clinical journals publish high-quality, clinically relevant and important original studies and systematic reviews, the articles for each discipline studied were concentrated in a small subset of journals. This subset varied according to healthcare discipline; however, many of the important articles for all disciplines in this study were published in broad-based healthcare journals rather than subspecialty or discipline-specific journals

    The impact of Cochrane Systematic Reviews : a mixed method evaluation of outputs from Cochrane Review Groups supported by the UK National Institute for Health Research

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    © 2014 Bunn et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: There has been a growing emphasis on evidence-informed decision making in health care. Systematic reviews, such as those produced by the Cochrane Collaboration, have been a key component of this movement. The UK National Institute for Health Research (NIHR) Systematic Review Programme currently supports 20 Cochrane Review Groups (CRGs). The aim of this study was to identify the impacts of Cochrane reviews published by NIHR funded CRGs during the years 2007-11. Methods: We sent questionnaires to CRGs and review authors, interviewed guideline developers and used bibliometrics and documentary review to get an overview of CRG impact and to evaluate the impact of a sample of 60 Cochrane reviews. We used a framework with four categories (knowledge production, research targeting, informing policy development, and impact on practice/services). Results: A total of 1502 new and updated reviews were produced by the 20 NIHR funded CRGs between 2007-11. The clearest impacts were on policy with a total of 483 systematic reviews cited in 247 sets of guidance; 62 were international, 175 national (87 from the UK) and 10 local. Review authors and CRGs provided some examples of impact on practice or services, for example safer use of medication, the identification of new effective drugs or treatments and potential economic benefits through the reduction in the use of unproven or unnecessary procedures. However, such impacts are difficult to objectively document and the majority of reviewers were unsure if their review had produced specific impacts. Qualitative data suggested that Cochrane reviews often play an instrumental role in informing guidance although a poor fit with guideline scope or methods, reviews being out of date and a lack of communication between CRGs and guideline developers were barriers to their use. Conclusions: Health and economic impacts of research are generally difficult to measure. We found that to be the case with this evaluation. Impacts on knowledge production and clinical guidance were easier to identify and substantiate than those on clinical practice. Questions remain about how we define and measure impact and more work is needed to develop suitable methods for impact analysis.Peer reviewe

    Release of PLGA–encapsulated dexamethasone from microsphere loaded porous surfaces

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    The aim of the present study was to investigate the morphology and function of a drug eluting metallic porous surface produced by the immobilization of poly lactide-co-glycolide microspheres bearing dexamethasone onto plasma electrolytically oxidized Ti–6Al–7Nb medical alloy. Spheres of 20 μm diameter were produced by an oil-in-water emulsion/solvent evaporation method and thermally immobilized onto titanium discs. The scanning electron microscopy investigations revealed that the size distribution and morphology of the attached spheres had not changed significantly. The drug release profiles following degradation in phosphate buffered saline for 1000 h showed that, upon immobilisation, the spheres maintained a sustained release, with a triphasic profile similar to the non-attached system. The only significant change was an increased release rate during the first 100 h. This difference was attributed to the effect of thermal attachment of the spheres to the surface
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