31 research outputs found
Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe
The Extragalactic Background Light (EBL) includes photons with wavelengths
from ultraviolet to infrared, which are effective at attenuating gamma rays
with energy above ~10 GeV during propagation from sources at cosmological
distances. This results in a redshift- and energy-dependent attenuation of the
gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts
(GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray
blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using
photons above 10 GeV collected by Fermi over more than one year of observations
for these sources, we investigate the effect of gamma-ray flux attenuation by
the EBL. We place upper limits on the gamma-ray opacity of the Universe at
various energies and redshifts, and compare this with predictions from
well-known EBL models. We find that an EBL intensity in the optical-ultraviolet
wavelengths as great as predicted by the "baseline" model of Stecker et al.
(2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication
in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A.
Reimer, L.C. Reye
SNAPSHOT USA 2019 : a coordinated national camera trap survey of the United States
This article is protected by copyright. All rights reserved.With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the USA. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as well as future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.Publisher PDFPeer reviewe
NVL-520 Is a Selective, TRK-Sparing, and Brain-Penetrant Inhibitor of ROS1 Fusions and Secondary Resistance Mutations
ROS1 tyrosine kinase inhibitors (TKI) have been approved (crizotinib and entrectinib) or explored (lorlatinib, taletrectinib, and repotrectinib) for the treatment of ROS1 fusion–positive cancers, although none of them simultaneously address the need for broad resistance coverage, avoidance of clinically dose-limiting TRK inhibition, and brain penetration. NVL-520 is a rationally designed macrocycle with >50-fold ROS1 selectivity over 98% of the kinome tested. It is active in vitro against diverse ROS1 fusions and resistance mutations and exhibits 10- to 1,000-fold improved potency for the ROS1 G2032R solvent-front mutation over crizotinib, entrectinib, lorlatinib, taletrectinib, and repotrectinib. In vivo, it induces tumor regression in G2032R-inclusive intracranial and patient-derived xenograft models. Importantly, NVL-520 has an ∼100-fold increased potency for ROS1 and ROS1 G2032R over TRK. As a clinical proof of concept, NVL-520 elicited objective tumor responses in three patients with TKI-refractory ROS1 fusion–positive lung cancers, including two with ROS1 G2032R and one with intracranial metastases, with no observed neurologic toxicities.Significance:The combined preclinical features of NVL-520 that include potent targeting of ROS1 and diverse ROS1 resistance mutations, high selectivity for ROS1 G2032R over TRK, and brain penetration mark the development of a distinct ROS1 TKI with the potential to surpass the limitations of earlier-generation TKIs for ROS1 fusion–positive patients.</p
The Clinically-tested S1P Receptor Agonists, FTY720 and BAF312, Demonstrate Subtype-Specific Bradycardia (S1P<sub>1</sub>) and Hypertension (S1P<sub>3</sub>) in Rat
<div><p>Sphingosine-1-phospate (S1P) and S1P receptor agonists elicit mechanism-based effects on cardiovascular function <em>in vivo</em>. Indeed, FTY720 (non-selective S1P<sub>X</sub> receptor agonist) produces modest hypertension in patients (2–3 mmHg in 1-yr trial) as well as acute bradycardia independent of changes in blood pressure. However, the precise receptor subtypes responsible is controversial, likely dependent upon the cardiovascular response in question (e.g. bradycardia, hypertension), and perhaps even species-dependent since functional differences in rodent, rabbit, and human have been suggested. Thus, we characterized the S1P receptor subtype specificity for each compound <em>in vitro</em> and, <em>in vivo</em>, the cardiovascular effects of FTY720 and the more selective S1P<sub>1,5</sub> agonist, BAF312, were tested during acute i.v. infusion in anesthetized rats and after oral administration for 10 days in telemetry-instrumented conscious rats. Acute i.v. infusion of FTY720 (0.1, 0.3, 1.0 mg/kg/20 min) or BAF312 (0.5, 1.5, 5.0 mg/kg/20 min) elicited acute bradycardia in anesthetized rats demonstrating an S1P<sub>1</sub> mediated mechanism-of-action. However, while FTY720 (0.5, 1.5, 5.0 mg/kg/d) elicited dose-dependent hypertension after multiple days of oral administration in rat at clinically relevant plasma concentrations (24-hr mean blood pressure = 8.4, 12.8, 16.2 mmHg above baseline <em>vs.</em> 3 mmHg in vehicle controls), BAF312 (0.3, 3.0, 30.0 mg/kg/d) had no significant effect on blood pressure at any dose tested suggesting that hypertension produced by FTY720 is mediated S1P<sub>3</sub> receptors. In summary, in vitro selectivity results in combination with studies performed in anesthetized and conscious rats administered two clinically tested S1P agonists, FTY720 or BAF312, suggest that S1P<sub>1</sub> receptors mediate bradycardia while hypertension is mediated by S1P<sub>3</sub> receptor activation.</p> </div
Plasma (nM) concentrations of FTY720 and the phosphorylated form of FTY720 after oral administration (0.5, 1.5, 5.0 mg/kg/d) or BAF312 after oral administration (0.3, 3.0, 30.0 mg/kg/d) at 4, 8, and 24 hrs post-dose on Day 1 and at 0, 4, 8, and 24 hrs post-dose on the last day of the study; values were quantified by mass spectrometry and are shown as mean±SEM.
<p>Plasma (nM) concentrations of FTY720 and the phosphorylated form of FTY720 after oral administration (0.5, 1.5, 5.0 mg/kg/d) or BAF312 after oral administration (0.3, 3.0, 30.0 mg/kg/d) at 4, 8, and 24 hrs post-dose on Day 1 and at 0, 4, 8, and 24 hrs post-dose on the last day of the study; values were quantified by mass spectrometry and are shown as mean±SEM.</p
Chemical structure of FTY720 (A) and BAF312 (B), the latter as reported by Thompson Integrity and as referred to as BAF312 throughout the publication.
<p>Chemical structure of FTY720 (A) and BAF312 (B), the latter as reported by Thompson Integrity and as referred to as BAF312 throughout the publication.</p
Effect of FTY720 and BAF312 on mean arterial pressure (MAP) and heart rate (HR) in conscious, telemetry-instrumented, rats during 10 days of daily oral administration.
<p>At doses that elicited no significant bradycardia, FTY720 elicited dose-dependent hypertension whereas BAF312 had no affect on MAP values at any dose tested during the study. FTY720 elicited dose-dependent increases in MAP at all doses tested (0.5, 1.5, and 5.0 mg/kg/d); 24-hr mean values over the treatment period increased 8.4±0.4, 12.8±0.4, and 16.2±0.8 mmHg, respectively, (vehicle = 3.7±0.5 mmHg) and values reached statistical significance in all treated groups (*p<0.05 <i>vs.</i> vehicle). However, BAF312 elicited no significant increase in mean arterial pressure during the study; average changes in 24-mean values during 14-days of treatment in the 0.3, 3.0, and 30 mg/kg/d dose groups were 3.0±0.5, 1.1±0.5, and 0.1±0.5 mmHg, respectively.</p