170 research outputs found

    Enhanced dynamic nuclear polarization via swept microwave frequency combs

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    Dynamic Nuclear Polarization (DNP) has enabled enormous gains in magnetic resonance signals and led to vastly accelerated NMR/MRI imaging and spectroscopy. Unlike conventional cw-techniques, DNP methods that exploit the full electron spectrum are appealing since they allow direct participation of all electrons in the hyperpolarization process. Such methods typically entail sweeps of microwave radiation over the broad electron linewidth to excite DNP, but are often inefficient because the sweeps, constrained by adiabaticity requirements, are slow. In this paper we develop a technique to overcome the DNP bottlenecks set by the slow sweeps, employing a swept microwave frequency comb that increases the effective number of polarization transfer events while respecting adiabaticity constraints. This allows a multiplicative gain in DNP enhancement, scaling with the number of comb frequencies and limited only by the hyperfine-mediated electron linewidth. We demonstrate the technique for the optical hyperpolarization of 13C nuclei in powdered microdiamonds at low fields, increasing the DNP enhancement from 30 to 100 measured with respect to the thermal signal at 7T. For low concentrations of broad linewidth electron radicals, e.g. TEMPO, these multiplicative gains could exceed an order of magnitude.Comment: Contains supplementary inf

    The Transcriptome Analysis of Strongyloides stercoralis L3i Larvae Reveals Targets for Intervention in a Neglected Disease

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    BackgroundStrongyloidiasis is one of the most neglected diseases distributed worldwide with endemic areas in developed countries, where chronic infections are life threatening. Despite its impact, very little is known about the molecular biology of the parasite involved and its interplay with its hosts. Next generation sequencing technologies now provide unique opportunities to rapidly address these questions.Principal FindingsHere we present the first transcriptome of the third larval stage of S. stercoralis using 454 sequencing coupled with semi-automated bioinformatic analyses. 253,266 raw sequence reads were assembled into 11,250 contiguous sequences, most of which were novel. 8037 putative proteins were characterized based on homology, gene ontology and/or biochemical pathways. Comparison of the transcriptome of S. strongyloides with those of other nematodes, including S. ratti, revealed similarities in transcription of molecules inferred to have key roles in parasite-host interactions. Enzymatic proteins, like kinases and proteases, were abundant. 1213 putative excretory/secretory proteins were compiled using a new pipeline which included non-classical secretory proteins. Potential drug targets were also identified.ConclusionsOverall, the present dataset should provide a solid foundation for future fundamental genomic, proteomic and metabolomic explorations of S. stercoralis, as well as a basis for applied outcomes, such as the development of novel methods of intervention against this neglected parasite

    Postsynaptic nigrostriatal dopamine receptors and their role in movement regulation

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    The article presents the hypothesis that nigrostriatal dopamine may regulate movement by modulation of tone and contraction in skeletal muscles through a concentration-dependent influence on the postsynaptic D1 and D2 receptors on the follow manner: nigrostriatal axons innervate both receptor types within the striatal locus somatotopically responsible for motor control in agonist/antagonist muscle pair around a given joint. D1 receptors interact with lower and D2 receptors with higher dopamine concentrations. Synaptic dopamine concentration increases immediately before movement starts. We hypothesize that increasing dopamine concentrations stimulate first the D1 receptors and reduce muscle tone in the antagonist muscle and than stimulate D2 receptors and induce contraction in the agonist muscle. The preceded muscle tone reduction in the antagonist muscle eases the efficient contraction of the agonist. Our hypothesis is applicable for an explanation of physiological movement regulation, different forms of movement pathology and therapeutic drug effects. Further, this hypothesis provides a theoretical basis for experimental investigation of dopaminergic motor control and development of new strategies for treatment of movement disorders

    Impact of family integrated care on infants’ clinical outcomes in two children’s hospitals in China: a pre-post intervention study

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    © 2018 The Author(s). Background: Most Neonatal Intensive Care Units (NICUs) in China have restricted visiting policies for parents. This also implicates that parents are not involved in the care of their infant. Family Integrated Care (FIC), empowering parents in direct care delivery and decisions, is becoming the standard in NICUs in many countries and can improve quality-of-life and health outcomes of preterm infants. The aim of this study was to evaluate the impact of a FIC intervention on the clinical outcomes of preterm infants with Bronchopulmonary Dysplasia (BPD). Methods: A pre-post intervention study was conducted at NICUs in two Chinese children's hospitals. Infants with BPD were included: pre-intervention group (n = 134) from December 2015 to September 2016, post-intervention (FIC) group (n = 115) and their parents from October 2016 to June 2017. NICU nurses were trained between July and September 2016 to deliver the FIC intervention, including parent education and support. Parents had to be present and care for their infant minimal three hours a day. The infants' outcome measures were length-of-stay, breastfeeding, weight gain, respiratory and oxygen support, and parent hospital expenses. Results: Compared with control group (n = 134), the FIC group (n = 115) had significantly increased breastfeeding rates (83% versus 71%, p = 0.030), breastfeeding time (31 days versus 19 days, p < 0.001), enteral nutrition time (50 days versus 34 days, p < 0.001), weight gain (29 g/day versus 23 g/day, p = 0.002), and significantly lower respiratory support time (16 days versus 25 days, p < 0.001). Oxygen Exposure Time decreased but not significant (39 days versus 41 days p = 0.393). Parents hospital expenses in local Chinese RMB currency was not significant (84 K versus 88 K, p = 0.391). Conclusion: The results of our study suggests that FIC is feasible in two Chinese NICUs and might improve clinical outcomes of preterm infants with BPD. Further research is needed to include all infants admitted to NICUs and should include parent reported outcome measures. Our study may help other NICUs with limited parental access to implement FIC to enhance parental empowerment and involvement in the care of their infant

    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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