35 research outputs found
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of binary black hole coalescences confidently observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include the effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that have already been identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total source-frame mass M > 70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz emitted gravitational-wave frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place a conservative upper limit for the merger rate density of high-mass binaries with eccentricities 0 < e ≤ 0.3 at 16.9 Gpc−3 yr−1 at the 90% confidence level
Charge carrier mobility in sulphonated and non-sulphonated Ni phthalocyanines: experiment and quantum chemical calculations
The objective of this interdisciplinary paper was to study theoretically and
experimentally the electronic part of charge carrier transport in the class
of sodium salts of sulphonated Ni phthalocyanine as candidates for p-type
channels in organic field-effect transistors. These materials were selected
because of their enhanced solubility as compared to their non-sulphonated
counterparts. The values of the field-effect charge carrier mobility
determined on the OFET structures using NiPc(SO3Na)x films were
much higher than the charge carrier mobility obtained on the respective
device prepared from non-substituted phthalocyanine. In order to explain
differences between charge carrier mobility of sulphonated and
non-sulphonated Ni phthalocyanines, quantum chemistry studies of molecular
aggregates were performed. Quantum chemistry modeling of the semiconductive
molecular systems is new and progressive – we highlighted factors at the
molecular level which led to the enhancement of the charge carrier mobility
in systems containing SO3Na groups
Autoantigens in primary biliary cirrhosis
The automimmune liver disease primary biliary cirrhosis (PBC) is characterised by serum autoantibodies directed at mitochondrial and nuclear antigens (seen in most patients and a subset of patients, respectively). The antimitochondrial antibodies (AMA) characteristic of PBC are directed at members of the 2-oxoacid dehydrogenase components of multienzyme complexes; in particular, the E2 and E3 binding protein (E3BP) components of the pyruvate dehydrogenase complex (PDC). The presence of autoantibodies reactive with PDC-E2 and/or E3BP is strongly predictive of the presence of PBC. Therefore, the detection of these antibodies plays a very important role in the diagnosis of PBC. Originally demonstrated using immunofluorescence approaches, AMA can now be detected by the use of commercially available enzyme linked immunosorbent assays (ELISAs). Although the ELISA based approaches have advantages in terms of laboratory practicality, they are slightly less sensitive for the diagnosis of PBC than immunofluorescence (occasional patients with PBC show reactivity with PDC related antigens not present in the antigen preparations available for use with ELISA). Therefore, immunofluorescence should continue to be available as a complementary diagnostic test for use in occasional patients. In a subset of patients with PBC, autoantibodies are directed at increasingly well characterised nuclear antigens. Antinuclear antibody (ANA) positive patients are typically AMA negative. There are no significant differences in disease phenotype between AMA positive and AMA negative groups. At present, the clinical detection of ANA is mostly by Hep2 immunofluorescence, although ELISA kits for individual nuclear antigens are increasingly becoming available. Key Words: liver cirrhosis • biliary • autoimmunity • autoantibod
GPCR-CARMA3-NF-kappaB Signaling Axis: A Novel Drug Target for Cancer Therapy
G protein-coupled receptors (GPCRs) play pivotal roles in regulating various cellular functions. It has been well established that GPCR activates NF-κB and aberrant regulation of GPCR-NF-κB signaling axis leads to cancers. However, how GPCRs induce NF-κB activation remains largely elusive. Recently, it has been shown that a novel scaffold protein, CARMA3, is indispensable in GPCR-induced NF-κB activation. In CARMA3-deficient mouse embryonic fibroblast cells, some GPCR ligand-, like lysophosphatidic acid (LPA), induced NF-κB activation is completely abolished. Mechanistically, upon GPCR activation, CARMA3 is linked to the membrane by β-arrestin 2 and phosphorylated by some PKC isoform. Phosphorylation of CARMA3 unfolds its steric structure and recruits its downstream effectors, which in turn activate the IKK complex and NF-κB. Interestingly, GPCR (LPA)-CARMA3-NF-κB signaling axis also exists in ovarian cancer cells, and knockdown of CARMA3 results in attenuation of ovarian cancer migration and invasion, suggesting a novel target for cancer therapy. In this review, we summarize the biology of CARMA3, discuss the GPCR (LPA)-CARMA3-NF-κB signaling axis in ovarian cancer and speculate its potential role in other types of cancers. With a strongly increasing tendency to identify more LPA-like ligands, such as endothelin-1 and angiotensin II, which also activate NF-κB through CARMA3 and contribute to myriad diseases, GPCR- CARMA3-NF-κB signaling axis is emerging as a novel drug target for various types of cancer and other myriad diseases
Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo
International audienceDespite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass ) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities at Gpc yr at 90% confidence level