319 research outputs found

    The Transient Ultra-luminous X-ray Source, ULX-4, in M51

    Full text link
    We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives, spanning the years 2000-2019. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed over the time intervals of 100-2000 second in the 0.3-10 keV energy band. We find some evidence for the existence of bi-modality feature in the flux distribution of ULX-4. We identified two optical sources as possible counterparts within an error radius of 0."18 at 95% confidence level for ULX-4 based on the archival HST/ACS and HST/WFC3 data. Blackbody fits of the spectral energy distributions (SEDs) indicate the spectral type to be B-type stars. One of these counterparts exhibits a low-amplitude optical periodicity of 264 days in the F606W filter; if we assume this apparent periodicity is associated with the orbital motion of the donor, then it is more likely that the donor is a red supergiant satisfying the long periodicity and accretion via Roche-lobe overflow. Consequently, the SED would then have to be interpreted as a superposition of emissions from a cold donor and a hot flow component, most likely from an accretion disk. If, on the other hand, the periodicity is super orbital in nature i.e., due to possible interactions of the compact object with a circumstellar disk, the donor could then be a Be/X star hosting a neutron star.Comment: Accepted for publication in MNRAS. 16 pages, 12 figures, 6 table

    White emitting CdS quantum dot nanoluminophores hybridized on near-ultraviolet LEDs for high-quality white light generation and tuning

    Get PDF
    To generate white light using semiconductor nanocrystal (NC) quantum dots integrated on light emitting diodes (LEDs), multiple hybrid device parameters (emission wavelengths of the NCs and the excitation platform, order of the NCs with different sizes, amount of the different types of NCs, etc) need to be carefully designed and properly implemented. In this study, we introduce and demonstrate white LEDs based on simple device hybridization using only a single type of white emitting CdS quantum dot nanoluminophores on near-ultraviolet LEDs. Here we present their design, synthesis-growth, fabrication and characterization. With these hybrid devices, we achieve high color rendering index (>70), despite using only a single NC type. Furthermore, we conveniently tune their photometric properties including the chromaticity coordinates, correlated color temperature, and color rendering index with the number of hybridized nanoluminophores in a controlled manner. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

    White CdS nanoluminophore based tunable hybrid light emitting diodes

    Get PDF
    [No abstract available

    Immunohistochemical neuroinflammatory markers in the hippocampus of PTZ-kindled rats under conditions of rapamycin and axitinib treatment

    No full text
    The aim of the study is to determine the level of HIF-1α, TNF-α, and NF-kB in the hippocampus of kindled rats treated with rapamycin and axitinib. Materials and methods. Kindling was produced in 29 rats by administration of three-week pentylenetetrazole (PTZ, 35.0 mg/kg, i.p.). Treatment with rapamycin (0.5 mg/kg, i.p.) and axitinib (2.5 mg/kg, i.p.) was performed for ten days in fully kindled rats. The avidin-biotin-peroxidase method was used for hippocampal slice staining. For negative control, staining was performed using only secondary antibodies. Results. The HIF-1α expression increased in kindled rats raised by 1.77 times compared to the control (p<0.001). Axitinib treatment resulted in of HIF-1α level of 16.7 % (p<0.05) compared with kindled animals, while combined treatment with rapamycin and axitinib reduced HIF-1α by 33.8 % (p<0.01). In kindled rats, TNF-α expression was 3.74 times greater than in control (p<0.001). Rapamycin treatment reduced TNF-α by 31.0 % (p<0.01). Axitinib treatment caused a reduction of TNF-α by 21.1 % (p<0.05). Combined treatment with rapamycin and axitinib reduced TNF-α by 48.0 % (p<0.001) but still exceeded the TNF-α in control by 1.95 times (p<0.01). NF-kB level in kindled rats exceeded the control by three times (p0.05), while axitinib – by 26.5 % (p<0.05) compared with kindled rats. Combined treatment with rapamycin and axitinib resulted in NF-kB reduction by 56.7 % compared with kindled rats (p<0.001). Conclusions. PTZ-kindling resulted in an increase in the immunoreactivity of HIF-1α, TNF-α, and NF-kB in the hippocampus. Combined treatment with rapamycin and axitinib engendered prevention of generalized seizures and normalized the level of HIF-1α and NF-kB with a significant reduction of TNF-α. Effects of treatment favours of synergy action of rapamycin and axitini

    Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

    Get PDF
    Irritable bowel syndrome with diarrhoea (IBS-D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS-D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work-up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS-D and FDr. In terms of diagnosis, the consensus supports a symptom-based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C-reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo-, di-, monosaccharides and polyols, gut-directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5-hydroxytryptamine-3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS-D and FDr
    corecore