50 research outputs found

    X-Ray Phase-Contrast Tomography of Renal Ischemia-Reperfusion Damage

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    Purpose: The aim of the study was to investigate microstructural changes occurring in unilateral renal ischemia-reperfusion injury in a murine animal model using synchrotron radiation. Material and Methods: The effects of renal ischemia-reperfusion were investigated in a murine animal model of unilateral ischemia. Kidney samples were harvested on day 18. Grating-Based Phase-Contrast Imaging (GB-PCI) of the paraffin-embedded kidney samples was performed at a Synchrotron Radiation Facility (beam energy of 19 keV). To obtain phase information, a two-grating Talbot interferometer was used applying the phase stepping technique. The imaging system provided an effective pixel size of 7.5 mu m. The resulting attenuation and differential phase projections were tomographically reconstructed using filtered back-projection. Semi-automated segmentation and volumetry and correlation to histopathology were performed. Results: GB-PCI provided good discrimination of the cortex, outer and inner medulla in non-ischemic control kidneys. Post-ischemic kidneys showed a reduced compartmental differentiation, particularly of the outer stripe of the outer medulla, which could not be differentiated from the inner stripe. Compared to the contralateral kidney, after ischemia a volume loss was detected, while the inner medulla mainly retained its volume (ratio 0.94). Post-ischemic kidneys exhibited severe tissue damage as evidenced by tubular atrophy and dilatation, moderate inflammatory infiltration, loss of brush borders and tubular protein cylinders. Conclusion: In conclusion GB-PCI with synchrotron radiation allows for non-destructive microstructural assessment of parenchymal kidney disease and vessel architecture. If translation to lab-based approaches generates sufficient density resolution, and with a time-optimized image analysis protocol, GB-PCI may ultimately serve as a non-invasive, non-enhanced alternative for imaging of pathological changes of the kidney

    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

    GH and the cardiovascular system: an update on a topic at heart

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    The Association Between Unwanted Sexual Experiences and Early-Onset Cervical Cancer and Precancer by Age 25: A Case-Control Study

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    BACKGROUND: We examined the association between unwanted sexual experiences and cervical cancer, cervical intraepithelial neoplasia 3, adenocarcinoma in situ, diagnosed ≤25 years of age. METHODS: A case-control study of women ≤55 years who attended gynecological hospitals in Australia between 1983 and 2007. Cases were ≤25 years when diagnosed with disease, control group 1 were "older women" >25 years at diagnosis; control group 2 were "well women" ≤25 years attending preventive health clinics. A self-administered postal survey was utilized. The main outcome measures were prevalence of childhood sexual abuse (<16 years) and unwanted adolescent sexual experiences (between 16 and 18 years) in cases compared to controls. RESULTS: Of 400 contactable subjects, 251 participated (62.8%). Prevalence of childhood sexual abuse in cases (26.6% [25/94]) was similar to other groups. Prevalence of childhood genital contact abuse in cases with cervical cancer was 45.5% [5/11], compared to older women (20% [10/50], p = 0.08) and well women (13.8% [8/58], p = 0.01), and was marginally more common compared to well women when adjusted for other lifestyle factors (odds ratio [OR]: 4.7 [1.0-22.6], p = 0.05). Prevalence of unwanted adolescent sexual experiences in cases was 28.9% [33/114]. Prevalence of adolescent penile-genital contact experiences in cervical cancer cases was 46.7% [7/15], compared to older women (9.4%, [6/64], p < 0.001) and well women (13.7%, [10/73], p = 0.003), and was more common compared to well women when adjusted for lifestyle (OR: 5.9 [1.4-24.9], p = 0.02) and sexual health risk factors (OR: 5.6 [1.4-22.1] p = 0.01). CONCLUSIONS: Unwanted sexual experiences with genital contact were a risk factor for invasive cervical cancer ≤25 years, likely due to a complex interplay of biological and environmental factors

    Impact of Anonymity and Identity Deception on Social Media eWOM

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    Part 4: Information Sharing on Social MediaInternational audienceBrand-related consumer to consumer communication, eWOM, is taking place in many forms across the social media space. Rules that governed credibility assessment of brand-related communication, WOM, in the Face to Face context may vary on social media, specifically because of anonymity that is afforded on different social media sites. The current study looks closely on the impact of anonymity in typical eWOM behaviour context on social media by drawing observations from a recent case in point and literature. The paper concludes with a list of relevant factors and propositions that must be tested empirically to draw greater understanding of the phenomenon
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