2,082 research outputs found

    Microresonator and associated method for producing and controlling photonic signals with a photonic bandgap delay apparatus

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    By applying a photonic signal to a microresonator that includes a photonic bandgap delay apparatus having a photonic band edge transmission resonance at the frequency of the photonic signal, the microresonator imparts a predetermined delay to the photonic signal. The photonic bandgap delay apparatus also preferably has a photonic band edge transmission resonance bandwidth which is at least as wide as the bandwidth of the photonic signal such that a uniform delay is imparted over the entire bandwidth of the photonic signal. The microresonator also includes a microresonator cavity, typically defined by a pair of switchable mirrors, within which the photonic bandgap delay apparatus is disposed. By requiring the photonic signal to oscillate within the microresonator cavity so as to pass through the photonic bandgap delay apparatus several times, the microresonator can controllably impart an adjustable delay to the photonic signal

    Variational models of network formation and ion transport: Applications to perfluorosulfonate ionomer membranes

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    We present the functionalized Cahn-Hilliard (FCH) energy, a continuum characterization of interfacial energy whose minimizers describe the network morphology of solvated functionalized polymer membranes. With a small set of parameters the FCH characterizes bilayer, pore-like, and micelle network structures. The gradient flows derived from the FCH describe the interactions between these structures, including the merging and pinch-off of endcaps and formation of junctions central to the generation of network morphologies. We couple the FCH gradient flow to a model of ionic transport which incorporates entropic effects to localize counter-ions, yielding a flow which dissipates a total free energy, and an expression for the excess electrochemical potential which combines electrostatic and entropic effects. We present applications to network bifurcation and membrane casting

    Synthesis and some properties of alkenyl carbanions stabilised by an α-boron atom

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    Methods for making boron-stabilised alkenyl carbanions and some of their reactions are presented. The calculated geometry and stabilisation energy of H2 Be=CH2 are given

    Decoupling of Sleep-Dependent Cortical and Hippocampal Interactions in a Neurodevelopmental Model of Schizophrenia

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    SummaryRhythmic neural network activity patterns are defining features of sleep, but interdependencies between limbic and cortical oscillations at different frequencies and their functional roles have not been fully resolved. This is particularly important given evidence linking abnormal sleep architecture and memory consolidation in psychiatric diseases. Using EEG, local field potential (LFP), and unit recordings in rats, we show that anteroposterior propagation of neocortical slow-waves coordinates timing of hippocampal ripples and prefrontal cortical spindles during NREM sleep. This coordination is selectively disrupted in a rat neurodevelopmental model of schizophrenia: fragmented NREM sleep and impaired slow-wave propagation in the model culminate in deficient ripple-spindle coordination and disrupted spike timing, potentially as a consequence of interneuronal abnormalities reflected by reduced parvalbumin expression. These data further define the interrelationships among slow-wave, spindle, and ripple events, indicating that sleep disturbances may be associated with state-dependent decoupling of hippocampal and cortical circuits in psychiatric diseases

    The clinical significance and impact of interleukin 15 on keratinocyte cell growth and migration

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    Chronic wounds represent a significant burden to health services and are associated with patient morbidity. Novel methods to diagnose and/or treat problematic wounds are needed. Interleukin (IL)-15 is a cytokine involved in a number of biological processes and disease states such as inflammation, healing and cancer progression. The current study explores the expression profile of IL-15 and IL-15 receptor α (IL-15Rα) in chronic wounds and its impact on keratinocytes. IL-15 and IL-15Rα expression were examined in healing and non-healing chronic wounds using qPCR and immunohistochemical analysis. The impact of recombinant IL-15 (rhIL-15) on human adult low calcium temperature (HaCaT) keratinocyte growth and migratory potential was further examined. IL-15 transcript expression was slightly, though non-significantly elevated in healing chronic wounds compared with non-healing chronic wounds. IL-15 protein staining was minimal in both subtypes of chronic wounds. By contrast, IL-15Rα transcript and protein expression were both observed to be enhanced in non-healing chronic wounds compared with healing chronic wounds. The treatment of HaCaT cells with rhIL-15 generally enhanced cell growth and promoted migration. Analysis with small molecule inhibitors suggested that the pro-migratory effect of rhIL-15 may be associated with ERK, AKT, PLCγ and FAK signalling. IL-15 may promote healing traits in keratinocytes and the differential expression of IL-15Rα is observed in chronic wounds. Together, this may imply a complex role for this interleukin in wound healing

    Improved detection of global copy number variation using high density, non-polymorphic oligonucleotide probes

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    <p>Abstract</p> <p>Background</p> <p>DNA sequence diversity within the human genome may be more greatly affected by copy number variations (CNVs) than single nucleotide polymorphisms (SNPs). Although the importance of CNVs in genome wide association studies (GWAS) is becoming widely accepted, the optimal methods for identifying these variants are still under evaluation. We have previously reported a comprehensive view of CNVs in the HapMap DNA collection using high density 500 K EA (Early Access) SNP genotyping arrays which revealed greater than 1,000 CNVs ranging in size from 1 kb to over 3 Mb. Although the arrays used most commonly for GWAS predominantly interrogate SNPs, CNV identification and detection does not necessarily require the use of DNA probes centered on polymorphic nucleotides and may even be hindered by the dependence on a successful SNP genotyping assay.</p> <p>Results</p> <p>In this study, we have designed and evaluated a high density array predicated on the use of non-polymorphic oligonucleotide probes for CNV detection. This approach effectively uncouples copy number detection from SNP genotyping and thus has the potential to significantly improve probe coverage for genome-wide CNV identification. This array, in conjunction with PCR-based, complexity-reduced DNA target, queries over 1.3 M independent NspI restriction enzyme fragments in the 200 bp to 1100 bp size range, which is a several fold increase in marker density as compared to the 500 K EA array. In addition, a novel algorithm was developed and validated to extract CNV regions and boundaries.</p> <p>Conclusion</p> <p>Using a well-characterized pair of DNA samples, close to 200 CNVs were identified, of which nearly 50% appear novel yet were independently validated using quantitative PCR. The results indicate that non-polymorphic probes provide a robust approach for CNV identification, and the increasing precision of CNV boundary delineation should allow a more complete analysis of their genomic organization.</p

    Recommendations for determining HPV status in patients with oropharyngeal cancers under TNM8 guidelines : a two-tier approach

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    ACKNOWLEDGEMENTS The funders had no role in study design, collection, data analysis or interpretation of the data. This work received funding from the Medical Research Council (D.Mc.C. and J.J.), the Health and Social Care Research and Development Division of the Northern Ireland Public Health Agency (D.M.c.C., J.J., M.Mo.), the Wellcome Trust through the Wellcome-FDS Research Training Fellowship, the Faculty of Dental Surgery of the Royal College of Surgeons of England (A.G.S.) and GlaxoSmithKline Ltd (T.J.). The Northern Ireland OPSCC TMAs used in this research were received from the Northern Ireland Biobank which has received funds from Health and Social Care Research and Development Division of the Public Health Agency in Northern Ireland and the Friends of the Cancer Centre. The Northern Ireland Cancer Registry who receives funding from the Northern Ireland Public Health Agency carried out collection of clinical data for the Northern Ireland OPSCC patients. The Faculty of Dental Surgery of the Royal College of Surgeons of England and the Liverpool Bio-innovation Hub Biobank carried out collection of clinical data for the Liverpool OPSCC patients.Peer reviewedPublisher PD

    An economic model of school-based behavioral interventions to prevent sexually transmitted infections

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    Objectives: Reducing sexually transmitted infections (STI) and teenage pregnancy through effective health education is a high priority for health policy. Behavioral interventions which teach skills to practice safer sex may reduce the incidence of STIs. We evaluated the cost-effectiveness of school-based behavioral interventions in young people. Methods: We developed an economic model to estimate the total number of STI cases averted, consequent gain in health related quality of life (HRQoL) and savings in medical costs, based on changes in sexual behavior. The parameters for the model were derived from a systematic literature search on the intervention effectiveness, epidemiology of STIs, sexual behavior and lifestyles, HRQoL and health service costs. Results: The costs of providing teacher-led and peer-led behavioral interventions were €5.16 and €18 per pupil, respectively. For a cohort of 1000 boys and 1000 girls aged 15 years, the model estimated that the behavioral interventions would avert two STI cases and save 0.35 Quality Adjusted Life Years (QALYs). Compared to standard education, the incremental cost-effectiveness of the teacher-led and peer-led interventions was €24,268 and €96,938 per QALY gained, respectively. Conclusions: School-based behavioral interventions which provide information and teach young people sexual health skills can bring about improvements in knowledge and increased self-efficacy, though these may be limited in terms of impact on sexual behavior. There was uncertainty around the results due to the limited effect of the intervention on behavioral outcomes and paucity of data for other input parameters
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