Combined ground and aerial measurements resolve vent-specific gas fluxes from a multi-vent volcano

Volcanoes with multiple summit vents present a methodological challenge for determining vent-specific gas emissions. Here, using a novel approach combining multiple ultraviolet cameras with synchronous aerial measurements, we calculate vent-specific gas compositions and fluxes for Stromboli volcano. Emissions from vent areas are spatially heterogeneous in composition and emission rate, with the central vent area dominating passive emissions, despite exhibiting the least explosive behaviour. Vents exhibiting Strombolian explosions emit low to negligible passive fluxes and are CO₂-dominated, even during passive degassing. We propose a model for the conduit system based on contrasting rheological properties between vent areas. Our methodology has advantages for resolving contrasting outgassing dynamics given that measured bulk plume compositions are often intermediate between those of the distinct vent areas. We therefore emphasise the need for a vent-specific approach at multi-vent volcanoes and suggest that our approach could provide a transformative advance in volcano monitoring applications.

Combining multiple ultraviolet cameras with synchronous aerial measurements, the authors here present vent-specific gas compositions and fluxes for Stromboli volcano. The results show that gas compositions vary between different vents, mirroring differences in eruptive behavior.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Abstract P1-06-04: Small-molecule screening nominates diverse combination therapies that sensitize BRCA mutant and wild-type triple negative breast cancer to PARP inhibition

Background: Triple negative breast cancer (TNBC) remains a heterogeneous clinical phenotype with few, known therapeutic targets. PARP inhibitors (PARPi) are the first approved, targeted therapy in TNBC, limited to germline BRCA mutant (BRCAm) cancers that lack homologous recombination repair capacity. Even in this context, resistance quickly emerges via secondary mutations that restore DNA repair ability. While DNA damage repair is an intriguing target in BRCA wild type (BRCAwt) TNBC due to inherent, genomic instability, PARPi alone have been ineffective in unselected populations. Systematic approaches to define novel drugs that sensitize BRCAwt and BRCAm TNBC to PARPi would greatly improve therapeutic efficacy and durability.

Methods: BRCAwt (HCC1806) and BRCAm (SUM149PT) cell lines were screened in duplicate using a 2,100-compound small molecule library. Cell lines were plated in media containing DMSO or sub-lethal doses of the PARPi, olaparib, onto Selleck Bioactive drug plates. Cell viability was assessed after 72 hours, then normalized to vehicle control. Hit cut-offs were predefined as log2 drug/DMSO of ≤ -0.7 with a viability difference greater than 20% -where stringent scoring thresholds were chosen to exceed the full range of scores observed in 816 empty control wells. Hits were sorted by target and pathway to provide mechanistic insight into the synergy of combinations. Drug combinations with the highest potential for near term translation were validated using GI50 viability assays in 9 BRCAwt and BRCAm TNBC cell lines. The most promising combination was further validated via immunoblotting, colony formation, and apoptosis assays.

Results: Several drug classes affecting well-known oncogenic signaling pathways conferred sensitivity to PARPi, with more hits in the BRCAm cell line. Relevant druggable targets sensitizing cells to olaparib in BRCAm TNBC that met the predefined cut-point were inhibitors of PI3K (pan-PI3K, PI3Kα and PI3Kβ specific), VEGFR, MEK, EGFR, NF-kB, aurora kinase and several DNA damaging agents. Aurora kinase, EGFR, and NF-kB inhibition sensitized cells to olaparib, yet upon further validation, synergy was mild. The screen identified ATM inhibitors, KU-55933 and KU-60019, as sensitizers of BRCAm cells to olaparib. The potent ATM inhibitor, AZD0156, and olaparib were a highly synergistic combination validated in all 9 BRCAm and BRCAwt TNBC cell lines via cell viability, annexin V, and colony formation assays. Immunoblotting of relevant DNA damage repair proteins showed that olaparib caused upregulation of p-ATM in BRCAm and BRCAwt cells. p-ATM expression decreased in response to combination ATM and PARP inhibition. Attenuated levels of p-ATM resulted in increased levels of p- and T-γH2AX, indicating an accumulation of double stranded DNA breaks.

Conclusion: In vitro, inhibition of several relevant, oncogenic pathways yielded sensitivity to PARPi in TNBC. We identified the ATM inhibitor, AZD0156, and olaparib as a potent combination regardless of BRCA status, a finding currently being evaluated in patient-derived in vivo models. Combination ATM plus PARP inhibitor therapy is a promising and feasible approach for near term translation in metastatic TNBC.

Citation Format: Sammons S, Yip C, Anderson G, Force J, Marcom K, Westbrook K, Anders CK, Blackwell K, Wood K. Small-molecule screening nominates diverse combination therapies that sensitize BRCA mutant and wild-type triple negative breast cancer to PARP inhibition [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-06-04.

Unresolved Gamma-Ray Sky through its Angular Power Spectrum

The gamma-ray sky has been observed with unprecedented accuracy in the last decade by the Fermi -large area telescope (LAT), allowing us to resolve and understand the high-energy Universe. The nature of the remaining unresolved emission [unresolved gamma-ray background (UGRB)] below the LAT source detection threshold can be uncovered by characterizing the amplitude and angular scale of the UGRB fluctuation field. This Letter presents a measurement of the UGRB autocorrelation angular power spectrum based on eight years of Fermi-LAT Pass 8 data products. The analysis is designed to be robust against contamination from resolved sources and noise systematics. The sensitivity to subthreshold sources is greatly enhanced with respect to previous measurements. We find evidence (with ∼3.7σ significance) that the scenario in which two classes of sources contribute to the UGRB signal is favored over a single class. A double power law with exponential cutoff can explain the anisotropy energy spectrum well, with photon indices of the two populations being 2.55±0.23 and 1.86±0.15.