1,327 research outputs found
Relativistic MHD modeling of magnetized neutron stars, pulsar winds, and their nebulae
Neutron stars are among the most fascinating astrophysical sources, being
characterized by strong gravity, densities about the nuclear one or even above,
and huge magnetic fields. Their observational signatures can be extremely
diverse across the electromagnetic spectrum, ranging from the periodic and
low-frequency signals of radio pulsars, up to the abrupt high-energy gamma-ray
flares of magnetars, where energies of ~10^46 erg are released in a few
seconds. Fast-rotating and highly magnetized neutron stars are expected to
launch powerful relativistic winds, whose interaction with the supernova
remnants gives rise to the non-thermal emission of pulsar wind nebulae, which
are known cosmic accelerators of electrons and positrons up to PeV energies. In
the extreme cases of proto-magnetars (magnetic fields of ~10^15 G and
millisecond periods), a similar mechanism is likely to provide a viable engine
for the still mysterious gamma-ray bursts. The key ingredient in all these
spectacular manifestations of neutron stars is the presence of strong magnetic
fields in their constituent plasma. Here we will present recent updates of a
couple of state-of-the-art numerical investigations by the high-energy
astrophysics group in Arcetri: a comprehensive modeling of the steady-state
axisymmetric structure of rotating magnetized neutron stars in general
relativity, and dynamical 3-D MHD simulations of relativistic pulsar winds and
their associated nebulae.Comment: EPS 44th Conference on Plasma Physics (June 2017, Belfast), paper
accepted for publication on Plasma Physics and Controlled Fusio
Id1 regulates angiogenesis through transcriptional repression of thrombospondin-1
AbstractId proteins are helix-loop-helix transcription factors that regulate tumor angiogenesis. In order to identify downstream effectors of Id1 involved in the regulation of angiogenesis, we performed PCR-select subtractive hybridization on wild-type and Id1 knockout mouse embryo fibroblasts (MEFs). Here we demonstrate that thrombospondin-1 (TSP-1), a potent inhibitor of angiogenesis, is a target of transcriptional repression by Id1. We also show that Id1-null MEFs secrete an inhibitor of endothelial cell migration, which is completely inactivated by depletion of TSP-1. Furthermore, in vivo studies revealed decreased neovascularization in matrigel assays in Id1-null mice compared to their wild-type littermates. This decrease was completely reversed by a TSP-1 neutralizing antibody. We conclude that TSP-1 is a major target for Id1 effects on angiogenesis
Androgen Receptor Modulation Optimized for Response (ARMOR) Phase I and II Studies: Galeterone for the Treatment of Castration-Resistant Prostate Cancer
Purpose: Galeterone is a selective, multitargeted agent that inhibits CYP17, antagonizes the androgen receptor (AR), and reduces AR expression in prostate cancer cells by causing an increase in AR protein degradation. These open-label phase I and II studies [Androgen Receptor Modulation Optimized for Response-1 (ARMOR1) and ARMOR2 part 1] evaluated the efficacy and safety of galeterone in patients with treatment-naive nonmetastatic or metastatic castration-resistant prostate cancer (CRPC) and established a dose for further study.
Experimental Design: In ARMOR1, 49 patients received increasing doses (650–2,600 mg) of galeterone in capsule formulation; 28 patients in ARMOR2 part 1 received increasing doses (1,700–3,400 mg) of galeterone in tablet formulation for 12 weeks. Patients were evaluated biweekly for safety and efficacy, and pharmacokinetic parameters were assessed.
Results: In ARMOR1, across all doses, 49.0% (24/49) achieved a ≥30% decline in prostate-specific antigen (PSA; PSA30) and 22.4% (11/49) demonstrated a ≥50% PSA decline (PSA50). In ARMOR2 part 1, across all doses, PSA30 was 64.0% (16/25) and PSA50 was 48.0% (12/25). In the 2,550-mg dose cohort, PSA30 was 72.7% (8/11) and PSA50 was 54.5% (6/11). Galeterone was well tolerated; the most common adverse events were fatigue, increased liver enzymes, gastrointestinal events, and pruritus. Most were mild or moderate in severity and required no action and there were no apparent mineralocorticoid excess (AME) events.
Conclusions: The efficacy and safety from ARMOR1 and ARMOR2 part 1 and the pharmacokinetic results support the galeterone tablet dose of 2,550 mg/d for further study. Galeterone was well tolerated and demonstrated pharmacodynamic changes consistent with its selective, multifunctional AR signaling inhibition
Compatibility and combination of world W -boson mass measurements
The compatibility of W-boson mass measurements performed by the ATLAS, LHCb, CDF, and D0 experiments is studied using a coherent framework with theory uncertainty correlations. The measurements are combined using a number of recent sets of parton distribution functions (PDF), and are further combined with the average value of measurements from the Large Electron–Positron collider. The considered PDF sets generally have a low compatibility with a suite of global rapidity-sensitive Drell–Yan measurements. The most compatible set is CT18 due to its larger uncertainties. A combination of all mW measurements yields a value of mW=80, 394.6±11.5 MeV with the CT18 set, but has a probability of compatibility of 0.5% and is therefore disfavoured. Combinations are performed removing each measurement individually, and a 91% probability of compatibility is obtained when the CDF measurement is removed. The corresponding value of the W boson mass is 80, 369.2±13.3 MeV, which differs by 3.6σ from the CDF value determined using the same PDF set
Evidence for an ηc(1S)π−resonance in B0→ηc(1S)K+π−decays
A Dalitz plot analysis of B0→ηc(1S)K+π− decays is performed using data samples of pp collisions collected with the LHCb detector at centre-of-mass energies of s√=7, 8 and 13TeV, corresponding to a total integrated luminosity of 4.7 fb −1. A satisfactory description of the data is obtained when including a contribution representing an exotic ηc(1S)π− resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096±20 +18−22MeV and 152±58 +60−35MeV, respectively. The spin-parity assignments JP=0+ and JP=1− are both consistent with the data. In addition, the first measurement of the B0→ηc(1S)K+π− branching fraction is performed and gives B(B0→ηc(1S)K+π−)=(5.73±0.24±0.13±0.66)×10−4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions
Gravitational waves from single neutron stars: an advanced detector era survey
With the doors beginning to swing open on the new gravitational wave
astronomy, this review provides an up-to-date survey of the most important
physical mechanisms that could lead to emission of potentially detectable
gravitational radiation from isolated and accreting neutron stars. In
particular we discuss the gravitational wave-driven instability and
asteroseismology formalism of the f- and r-modes, the different ways that a
neutron star could form and sustain a non-axisymmetric quadrupolar "mountain"
deformation, the excitation of oscillations during magnetar flares and the
possible gravitational wave signature of pulsar glitches. We focus on progress
made in the recent years in each topic, make a fresh assessment of the
gravitational wave detectability of each mechanism and, finally, highlight key
problems and desiderata for future work.Comment: 39 pages, 12 figures, 2 tables. Chapter of the book "Physics and
Astrophysics of Neutron Stars", NewCompStar COST Action 1304. Minor
corrections to match published versio
Observation of an Excited Bc+ State
Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
Clinical Effectiveness of Transversus Abdominis Plane (TAP) Block versus Local Anesthesia Wound Infiltration for Postoperative Pain Relief After Laparoscopic Appendicectomy in Children: A Study Protocol for a Multicenter Double-Blind Randomized Controlled Phase III Trial
Geoffrey Bloy,1 Amelie Jurine,1 Yann Chaussy,2 Frederic Auber,2 Pierre-Gregoire Guinot,3 Belaid Bouhemad,3 Michel Francois,4 Lucie Vettoretti,1 Sebastien Pili-Floury,5 Maxime Nguyen,3 Guillaume Besch5 1CHU Besançon, Département d’Anesthésie Réanimation Chirurgicale, Besançon, F-25000, France; 2Université de Franche-Comté, CHU Besançon, SINERGIES, Service de Chirurgie Pédiatrique, Besançon, F-25000, France; 3University of Burgundy and Franche-Comté, Dijon University Hospital, INSERM LNC UMR1231, FCS Bourgogne Franche-Comté LipSTIC LabEx, Dijon, F-21000, France; 4Université de Bourgogne, CHU Dijon, Service de Chirurgie Pédiatrique, Dijon, F-21000, France; 5Université de Franche-Comté, CHU Besançon, SINERGIES, Département d’Anesthésie Réanimation Chirurgicale, Besançon, F-25000, FranceCorrespondence: Guillaume Besch, Département d’Anesthésie Réanimation Chirurgicale, CHU Besançon, 3 bvd Alexandre Fleming, Besançon, 25030, France, Tel +3381218958, Fax +3381669331, Email [email protected]: Postoperative pain relief after laparoscopic appendicectomy is a key determinant of early rehabilitation in children. Recent guidelines recommend performing either a transversus abdominis plane (TAP) block or local anesthesia (LA) wound infiltration as part of multimodal postoperative analgesia after appendectomy. To date, the clinical effectiveness of TAP block versus LA wound infiltration has never been compared. The hypothesis of this study is that the TAP block may provide a greater opioid-sparing effect after laparoscopic appendicectomy in children than LA wound infiltration.Study Design and Methods: We designed a multicenter double-blind randomized controlled phase III trial and aim to include 110 children who undergo laparoscopic appendicectomy. Children are randomized to receive either TAP block (TAP group) or LA wound infiltration (infiltration group). Multimodal analgesia is standardized in the two groups using the same protocol, which includes the stepwise prescription of paracetamol, phloroglucinol, ketoprofene, and nalbuphine according to the hetero-evaluation of pain performed by the nurses who were blinded to the treatment allocated using the validated FLACC scale. The primary outcome is the total dose of nalbuphine administered within 24 hours after surgery.Discussion: No study has specifically compared the clinical effectiveness of TAP block versus LA wound infiltration for postoperative pain relief after laparoscopic appendectomy in children. This paper describes the protocol for a randomized trial that addresses this issue. The results of this trial will be useful for editing guidelines with a higher level of evidence on this topic.Keywords: laparoscopic appendectomy, TAP block, wound infiltration, analgesia, childre
Alkaline-earth phosphonate MOFs with reversible hydration-dependent fluorescence
A new rigid tritopic phosphonic ligand, 2,4,6-tris(4-phosphonophenyl)pyridine (H6L), was synthesized and used to assemble isostructural barium (1) and strontium (2) phosphonate metal organic frameworks that exhibit fully reversible and selective water-dependent fluorescence red-shift at room temperature
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