26 research outputs found

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

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    Clinical Controversy in Transplantation: Tacrolimus Versus Cyclosporine in Statin Drug Interactions

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    Objective: To review the available literature that provides evidence for the absence of statin interactions with tacrolimus compared with cyclosporine. Data Sources: A literature search of PubMed was performed (1990 to June 2019) using the following search terms: calcineurin inhibitors, tacrolimus, cyclosporine, statins, atorvastatin, simvastatin, and drug interactions. Clinical practice guidelines, article bibliographies, drug interaction database references, and product monographs were also reviewed. Study Selection and Data Extraction: Relevant English-language studies describing the mechanism of interaction, the magnitude of pharmacokinetic alterations, and safety were evaluated. In vitro data and studies conducted in adult humans were considered. Data Synthesis: Studies demonstrate pharmacokinetic differences between cyclosporine and tacrolimus, particularly with regard to inhibition of 2 hepatic transporters: P-glycoprotein and organic anion transporting polypeptide (OATP). Compared with cyclosporine, tacrolimus does not affect these transporters, does not enhance statin exposure, and does not increase statin-associated safety events. Relevance to Patient Care and Clinical Practice: Clinical practice guidelines allude to the need to reduce statin doses in the setting of tacrolimus. Some providers have adopted this practice, and doing so may prevent transplant recipients from attaining cardiovascular benefit, especially when increased or high-intensity doses are required. The pharmacokinetic differences between tacrolimus and cyclosporine highlight different interaction potential with statins. Conclusions: Clinicians need to be aware that tacrolimus and cyclosporine are not the same with regard to causing drug interactions with statins. Tacrolimus can be used with statins without the need for dose adjustments because of lack of an interaction

    Optical Detection and Sizing of Single Nanoparticles Using Continuous Wetting Films

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    The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm(2) using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm(2). These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs

    Glioma progression is shaped by genetic evolution and microenvironment interactions

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    © 2022 Elsevier Inc.The factors driving therapy resistance in diffuse glioma remain poorly understood. To identify treatment-associated cellular and genetic changes, we analyzed RNA and/or DNA sequencing data from the temporally separated tumor pairs of 304 adult patients with isocitrate dehydrogenase (IDH)-wild-type and IDH-mutant glioma. Tumors recurred in distinct manners that were dependent on IDH mutation status and attributable to changes in histological feature composition, somatic alterations, and microenvironment interactions. Hypermutation and acquired CDKN2A deletions were associated with an increase in proliferating neoplastic cells at recurrence in both glioma subtypes, reflecting active tumor growth. IDH-wild-type tumors were more invasive at recurrence, and their neoplastic cells exhibited increased expression of neuronal signaling programs that reflected a possible role for neuronal interactions in promoting glioma progression. Mesenchymal transition was associated with the presence of a myeloid cell state defined by specific ligand-receptor interactions with neoplastic cells. Collectively, these recurrence-associated phenotypes represent potential targets to alter disease progression.N
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