2,855 research outputs found

    Together at Last bHLH and LIM-HD Regulators Cooperate to Specify Motor Neurons

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    AbstractbHLH and LIM-HD transcription factors were originally thought to act at different stages of neurogenesis: bHLHs as neuronal “inducers” and LIM-HDs as postmitotic subtype determinants. These distinctions are becoming blurred, and a current study by Lee and Pfaff in this issue of Neuron shows that interaction between these factors functions to synchronize neurogenesis with neuronal cell type specification

    Conservation Evaluation of Small-flowered Lipocarpha, Lipocarpha micrantha (Cyperaceae), in Canada

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    In Canada, Lipocarpha micrantha has been documented at eight locations in Quebec, Ontario, and British Columbia. Four of these populations have apparently been extirpated. The remaining populations, ranging from 120 to approximately 40000 plants, are all northern disjuncts from the main range of this species. Threats to these populations include water level regulation and shoreline development. Considering the threats to the habitat of Lipocarpha micrantha, and the small size of most of the remaining populations, it has been designated an Endangered species in Canada

    FPGA implementation of a cyclostationary detector for OFDM signals

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    Due to the ubiquity of Orthogonal Frequency Division Multiplexing (OFDM) based communications standards such as IEEE 802.11 a/g/n and 3GPP Long Term Evolution (LTE), a growing interest has developed in techniques for reliably detecting the presence of these signals in dynamic radio systems. A popular approach for detection is to exploit the cyclostationary nature of OFDM communications signals. In this paper, we focus on a frequency domain cyclostationary detection algorithm first introduced by Giannakis and Dandawate and study its performance in detecting IEEE 802.11a OFDM signals in the presence of practical radio impairments such as Carrier Frequency offset (CFO), Phase Noise, I/Q Imbalance, Multipath Fading and DC offset. We then present a hardware implementation of this algorithm developed using MathWorks HDL Coder and provide implementation results after targeting to a Xilinx 7 Series FPGA device

    Specification of Neuropeptide Cell Identity by the Integration of Retrograde BMP Signaling and a Combinatorial Transcription Factor Code

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    AbstractIndividual neurons express only one or a few of the many identified neurotransmitters and neuropeptides, but the molecular mechanisms controlling their selection are poorly understood. In the Drosophila ventral nerve cord, the six Tv neurons express the neuropeptide gene FMRFamide. Each Tv neuron resides within a neuronal cell group specified by the LIM-homeodomain gene apterous. We find that the zinc-finger gene squeeze acts in Tv cells to promote their unique axon pathfinding to a peripheral target. There, the BMP ligand Glass bottom boat activates the Wishful thinking receptor, initiating a retrograde BMP signal in the Tv neuron. This signal acts together with apterous and squeeze to activate FMRFamide expression. Reconstituting this “code,” by combined BMP activation and apterous/squeeze misexpression, triggers ectopic FMRFamide expression in peptidergic neurons. Thus, an intrinsic transcription factor code integrates with an extrinsic retrograde signal to select a specific neuropeptide identity within peptidergic cells

    Segmentally homologous neurons acquire two different terminal neuropeptidergic fates in the Drosophila nervous system

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    This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. In this study, we identify the means by which segmentally homologous neurons acquire different neuropeptide fates in Drosophila. Ventral abdominal (Va)-neurons in the A1 segment of the ventral nerve cord express DH31 and AstA neuropeptides (neuropeptidergic fate I) by virtue of Ubx activity, whereas the A2-A4 Va-neurons express the Capa neuropeptide (neuropeptidergic fate II) under the influence of abdA. These different fates are attained through segment-specific programs of neural subtype specification undergone by segmentally homologous neurons. This is an attractive alternative by which Hox genes can shape Drosophila segmental neural architecture (more sophisticated than the previously identified binary “to live” or “not to live” mechanism). These data refine our knowledge of the mechanisms involved in diversifying neuronal identity within the central nervous systemThis study was supported by grant number: BFU2013-43858-

    QT peak prolongation predicts cardiac death following stroke

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    Cardiac death has been linked in many populations to prolongation of the QT interval (QTe). However, basic science research suggested that the best estimate of the time point when repolarisation begins is near the T-wave peak. We found QT peak (QTp) was longer in hypertensive subjects with LVH. A prolonged “depolarisation” phase, rather than “repolarisation” (T peak to T end) might therefore account for the higher incidence of cardiac death linked to long QT. Hypothesis: We have tested the hypothesis that QT peak (QTp) prolongation predicts cardiac death in stroke survivors. Methods and Results: ECGs were recorded from 296 stroke survivors (152 male), mean age 67.2 (SD 11.6) approximately 1 year after the event. Their mean blood pressure was 152/88 mmHg (SD 29/15mmHg). These ECGs were digitised by one observer who was blinded to patient outcome. The patients were followed up for a median of 3.3 years. The primary endpoint was cardiac death. A prolonged heart rate corrected QT peak (QTpc) of lead I carried the highest relative risk of death from all cause as well as cardiac death, when compared with the other more conventional QT indices. In multivariate analyses, when adjusted for conventional risk factors of atherosclerosis, a prolonged QTpc of lead I was still associated with a 3-fold increased risk of cardiac death. (adjusted relative risk 3.0 [95% CI 1.1 - 8.5], p=0.037). Conclusion: QT peak prolongation in lead I predicts cardiac death after strok

    Direct characterisation of tuneable few-femtosecond dispersive-wave pulses in the deep UV

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    Dispersive wave emission (DWE) in gas-filled hollow-core dielectric waveguides is a promising source of tuneable coherent and broadband radiation, but so far the generation of few-femtosecond pulses using this technique has not been demonstrated. Using in-vacuum frequency-resolved optical gating, we directly characterise tuneable 3fs pulses in the deep ultraviolet generated via DWE. Through numerical simulations, we identify that the use of a pressure gradient in the waveguide is critical for the generation of short pulses.Comment: 5 pages, 4 figure

    Effect of pioglitazone treatment on behavioral symptoms in autistic children

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    INTRODUCTION: Autism is complex neuro-developmental disorder which has a symptomatic diagnosis in patients characterized by disorders in language/communication, behavior, and social interactions. The exact causes for autism are largely unknown, but is has been speculated that immune and inflammatory responses, particularly those of Th2 type, may be involved. Thiazolidinediones (TZDs) are agonists of the peroxisome proliferator activated receptor gamma (PPARγ), a nuclear hormone receptor which modulates insulin sensitivity, and have been shown to induce apoptosis in activated T-lymphocytes and exert anti-inflammatory effects in glial cells. The TZD pioglitazone (Actos) is an FDA-approved PPARγ agonist used to treat type 2 diabetes, with a good safety profile, currently being tested in clinical trials of other neurological diseases including AD and MS. We therefore tested the safety and therapeutic potential of oral pioglitazone in a small cohort of children with diagnosed autism. CASE DESCRIPTION: The rationale and risks of taking pioglitazone were explained to the parents, consent was obtained, and treatment was initiated at either 30 or 60 mg per day p.o. A total of 25 children (average age 7.9 ± 0.7 year old) were enrolled. Safety was assessed by measurements of metabolic profiles and blood pressure; effects on behavioral symptoms were assessed by the Aberrant Behavior Checklist (ABC), which measures hyperactivity, inappropriate speech, irritability, lethargy, and stereotypy, done at baseline and after 3–4 months of treatment. DISCUSSION AND EVALUATION: In a small cohort of autistic children, daily treatment with 30 or 60 mg p.o. pioglitazone for 3–4 months induced apparent clinical improvement without adverse events. There were no adverse effects noted and behavioral measurements revealed a significant decrease in 4 out of 5 subcategories (irritability, lethargy, stereotypy, and hyperactivity). Improved behaviors were inversely correlated with patient age, indicating stronger effects on the younger patients. CONCLUSION: Pioglitazone should be considered for further testing of therapeutic potential in autistic patients
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