39 research outputs found

    PATRIOT: A phase I study to assess the tolerability, safety and biological effects of a specific ataxia telangiectasia and Rad3-related (ATR) inhibitor (AZD6738) as a single agent and in combination with palliative radiation therapy in patients with solid tumours.

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    PATRIOT is a phase I study of the ATR inhibitor, AZD6738, as monotherapy, and in combination with palliative radiotherapy. Here, we describe the protocol for this study, which opened in 2014 and is currently recruiting and comprises dose escalation of both drug and radiotherapy, and expansion cohorts

    Dark Matter and Fundamental Physics with the Cherenkov Telescope Array

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    The Cherenkov Telescope Array (CTA) is a project for a next-generation observatory for very high energy (GeV-TeV) ground-based gamma-ray astronomy, currently in its design phase, and foreseen to be operative a few years from now. Several tens of telescopes of 2-3 different sizes, distributed over a large area, will allow for a sensitivity about a factor 10 better than current instruments such as H.E.S.S, MAGIC and VERITAS, an energy coverage from a few tens of GeV to several tens of TeV, and a field of view of up to 10 deg. In the following study, we investigate the prospects for CTA to study several science questions that influence our current knowledge of fundamental physics. Based on conservative assumptions for the performance of the different CTA telescope configurations, we employ a Monte Carlo based approach to evaluate the prospects for detection. First, we discuss CTA prospects for cold dark matter searches, following different observational strategies: in dwarf satellite galaxies of the Milky Way, in the region close to the Galactic Centre, and in clusters of galaxies. The possible search for spatial signatures, facilitated by the larger field of view of CTA, is also discussed. Next we consider searches for axion-like particles which, besides being possible candidates for dark matter may also explain the unexpectedly low absorption by extragalactic background light of gamma rays from very distant blazars. Simulated light-curves of flaring sources are also used to determine the sensitivity to violations of Lorentz Invariance by detection of the possible delay between the arrival times of photons at different energies. Finally, we mention searches for other exotic physics with CTA.Comment: (31 pages, Accepted for publication in Astroparticle Physics

    Massive binary black holes in galactic nuclei and their path to coalescence

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    Massive binary black holes form at the centre of galaxies that experience a merger episode. They are expected to coalesce into a larger black hole, following the emission of gravitational waves. Coalescing massive binary black holes are among the loudest sources of gravitational waves in the Universe, and the detection of these events is at the frontier of contemporary astrophysics. Understanding the black hole binary formation path and dynamics in galaxy mergers is therefore mandatory. A key question poses: during a merger, will the black holes descend over time on closer orbits, form a Keplerian binary and coalesce shortly after? Here we review progress on the fate of black holes in both major and minor mergers of galaxies, either gas-free or gas-rich, in smooth and clumpy circum-nuclear discs after a galactic merger, and in circum-binary discs present on the smallest scales inside the relic nucleus.Comment: Accepted for publication in Space Science Reviews. To appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher

    Preemptive analgesia. Clinical evidence of neuroplasticity contributing to postoperative pain.

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    Recent evidence suggests that surgical incision and other noxious perioperative events may induce prolonged changes in central neural function that later contribute to postoperative pain. The present study tested the hypothesis that patients receiving epidural fentanyl before incision would have less pain and need fewer analgesics post-operatively than patients receiving the same dose of epidural fentanyl after incision. Thirty patients (ASA physical status 2) scheduled for elective thoracic surgery through a posterolateral thoracotomy incision were randomized to one of two groups of equal size and prospectively studied in a double-blind manner. Epidural catheters were placed via the L2-L3 or L3-L4 interspaces preoperatively, and the position was confirmed with lidocaine. Group 1 received epidural fentanyl (4 micrograms/kg, in 20 ml normal saline) before surgical incision, followed by epidural normal saline (20 ml) infused 15 min after incision. Group 2 received epidural normal saline (20 ml) before surgical incision, followed by epidural fentanyl (4 micrograms/kg, in 20 ml normal saline) infused 15 min after incision. No additional analgesics were used before or during the operation. Anesthesia was induced with thiopental (3-5 mg/kg) and maintained with N2O/O2 and isoflurane. Paralysis was achieved with pancuronium (0.1 mg/kg). Postoperative analgesia consisted of patient-controlled intravenous morphine. Visual analogue scale pain scores were significantly less in group 1 (2.6 +/- 0.44) than in group 2 (4.7 +/- 0.58) 6 h after surgery (P less than 0.05), by which time plasma fentanyl concentrations had decreased to subtherapeutic levels (less than 0.15 ng/ml) in both groups

    Multimodal analgesia before thoracic surgery does not reduce postoperative pain

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    Several reports have suggested that preoperative nociceptive block may reduce postoperative pain, analgesic requirements, or both, beyond the anticipated duration of action of the analgesic agents. We have investigated, in a double-blind, placebo-controlled study, pre-emptive analgesia and the respiratory effects of preoperative administration of a multimodal antinociceptive regimen. Thirty patients undergoing thoracotomy were allocated randomly to two groups. Before surgery, the treatment group (n = 15) received morphine 0.15 mg kg−1 i.m. with perphenazine 0.03mg kg−1 i.m. and a rectal suppository of indomethacin 100 mg, while the placebo group (n = 15) received midazolam 0.05mg kg−1 i.m. and a placebo rectal suppository. After induction of anaesthesia, the treatment group received intercostal nerve block with 0.5% bupivacaine and adrenaline 1:200000 (3 ml) in the interspace of the incision and in the two spaces above and two spaces below. The placebo group received identical injections but with normal saline only. The treatment group consumed significantly less morphine by patient-controlled analgesia in the first 6 h after operation, but the total dose of morphine consumed on days 2 and 3 after surgery was significantly greater in the treatment group. There were no differences between the groups in postoperative VAS scores (at rest or after movement), Paco2 values or postoperative spirometry. However, pain thresholds to pressure applied at the side of the chest contralateral to the site of incision decreased significantly from preoperative values on days 1 and 2 after surgery in both groups. The results of this study do not support the preoperative use of this combined regimen for post-thoracotomy pain

    The density and pseudo-phase-space density profiles of cold dark matter haloes

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    Cosmological N-body simulations indicate that the spherically-averaged density profiles of cold dark matter halos are accurately described by Einasto profiles, where the logarithmic slope is a power-law of adjustable exponent, \gamma =dln\rho /dlnr ~ r^\alpha $. The pseudo-phase-space density (PPSD) profiles of CDM halos also show remarkable regularity, and are well approximated by simple power laws, Q(r)=\rho /\sigma ^3 ~ r^-\chi . We show that this is expected from dynamical equilibrium considerations, since Jeans' equations predict that the pseudo-phase-space density profiles of Einasto halos should resemble power laws over a wide range of radii. For the values of \alpha typical of CDM halos, the inner Q profiles of equilibrium halos deviate significantly from a power law only very close to the center, and simulations of extremely high-resolution would be needed to detect such deviations unambiguously. We use an ensemble of halos drawn from the Millennium-II simulation to study which of these two alternatives describe best the mass profile of CDM halos. Our analysis indicates that at the resolution of the best available simulations, both Einasto and power-law PPSD profiles (with adjustable exponents \alpha and \chi, respectively) provide equally acceptable fits to the simulations. A full account of the structure of CDM halos requires understanding how the shape parameters that characterize departures from self-similarity, like \alpha or \chi, are determined by evolutionary history, environment or initial conditions.Comment: 9 pages, 7 figures, submitted to MNRA
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