4,933 research outputs found

    Endoscopic Retrograde Cholangiopancreatography in Elderly Patients

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    SUMMARYEndoscopic retrograde cholangiopancreatography (ERCP) is effective in the investigation and treatment of pan-creatic and biliary disease. As the prevalence of bile duct stones and malignant disease and the risk of surgery rise with age, studies on the therapeutic success of ERCP in the elderly become more popular. There have been publications documenting the safety of ERCP in elderly patients from the age of 65 to 85 years. Recent studies have also shown that ERCP is safe and effective in those aged 90 years and older. Outcomes of ERCP in terms of success and complication rates are similar to those in younger patients. Therefore, the decision to undergo ERCP should be determined by clinical need, and age alone should not be a contraindication to endoscopic intervention. Here, we review the indications, pre-procedure preparation, sedation and analgesia, monitoring/procedural care, complications, and outcomes of diagnostic and therapeutic ERCP in the elderly

    Quasi-Periodic Variations in X-ray Emission and Long-Term Radio Observations: Evidence for a Two-Component Jet in Sw J1644+57

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    The continued observations of Sw J1644+57 in X-ray and radio bands accumulated a rich data set to study the relativistic jet launched in this tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days presents two kinds of quasi-periodic variations: a 200 second quasi-periodic oscillation (QPO) and a 2.7-day quasi-periodic variation. The latter has been interpreted by a precessing jet launched near the Bardeen-Petterson radius of a warped disk. Here we suggest that the \sim 200s QPO could be associated with a second, narrower jet sweeping the observer line-of-sight periodically, which is launched from a spinning black hole in the misaligned direction with respect to the black hole's angular momentum. In addition, we show that this two-component jet model can interpret the radio light curve of the event, especially the re-brightening feature starting 100\sim 100 days after the trigger. From the data we infer that inner jet may have a Lorentz factor of Γj5.5\Gamma_{\rm j} \sim 5.5 and a kinetic energy of Ek,iso3.0×1052ergE_{\rm k,iso} \sim 3.0 \times 10^{52} {\rm erg}, while the outer jet may have a Lorentz factor of Γj2.5\Gamma_{\rm j} \sim 2.5 and a kinetic energy of Ek,iso3.0×1053ergE_{\rm k,iso} \sim 3.0 \times 10^{53} {\rm erg}.Comment: 11 pages, 7 figures, accepted for publication in Ap

    AT2022cmc: a Tidal Disruption Event with Two-component Jet in a Bondi-profile Circumnuclear Medium

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    A supermassive black hole can launch a relativistic jet when it violently disrupts a star that passes too close. Such jetted tidal disruption events (TDEs) are rare and unique tools to investigate quiescent supermassive black holes, jet physics, and circumnuclear environment at high redshift. The newly discovered TDE AT2022cmc (z1.193z\sim 1.193) providing rich multi-band (X-ray, UV, optical, sub-millimeter, and radio) data, has been interpreted as the fourth on-axis jetted TDE. In this work, we constrain the circumnuclear medium (CNM) density profile with both closure relation (CR) test and detailed forward shock model fit with Markov chain Monte Carlo (MCMC) approach to the multi-band (optical, sub-millimeter, and radio) data of AT2022cmc.We find that the CNM density profile of AT2022cmc is nRkn\propto R^{-k} with k1.68k \sim 1.68, implying a Bondi accretion in history. Furthermore, our model fit result suggests a two-component jet in AT2022cmc, indicating a similar jet physics to well-studied jetted TDE Sw J1644+57.Comment: accepted in Ap
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