Science results from sixteen years of MRO SHARAD operations

In operation for >16 years to date, the Mars Reconnaissance Orbiter (MRO) Shallow Radar (SHARAD) sounder has acquired data at its nominal 300–450 m along-track and 3-km cross-track resolution covering >55% of the Martian surface, with nearly 100% overlap in coverage at that scale in the polar regions and in a number of smaller mid-latitude areas. While SHARAD data have opened a new window into understanding the interior structures and properties of Martian ices, volcanics, and sedimentary deposits up to a few kilometers in depth, they have also led to new revelations about the deeper interior and the behavior of the planet’s ionosphere. Here we summarize the data collected by SHARAD over this time period, the methods used in the analysis of that data, and the resulting scientific findings. The polar data are especially rich, revealing complex structures that comprise up to several dozen reflecting interfaces that extend to depths of 3 km, which inform the evolution of Martian climate in the late Amazonian period. SHARAD observations of mid-latitude lobate debris aprons and other glacier-like landforms detect strong basal reflections and low dielectric loss, confirming that they are icerich debris-covered glaciers. In other mid-latitude terrains, SHARAD data demonstrate the presence of widespread ground ices, likely at lower concentrations. SHARAD signals also probe non-icy materials, mapping out stacked lava flows, probing low-density materials thought to be ash-fall deposits, and occasionally penetrating sedimentary deposits, all of which reveal the structures and interior properties diagnostic of emplacement processes. SHARAD signals are impacted by their passage through the Martian ionosphere, revealing variations in time and space of the total electron content linked with the remanent magnetic field. Advanced techniques developed over the course of the mission, which include subband and super-resolution processing, coherent and incoherent summing, and three-dimensional (3D) radar imaging, are enabling new discoveries and extending the utility of the data. For 3D imaging, a cross-track spacing at the nominal 3-km resolution is more than sufficient to achieve good results, but finer spacing of 0.5 km or less significantly improves the spatially interpolated radar images. Recent electromagnetic modeling and a flight test show that SHARAD’s signal-to-noise ratio can be greatly improved with a large (~120◦) roll of the spacecraft to reduce interference with the spacecraft body. Both MRO and SHARAD are in remarkably fine working order, and the teams look forward to many more years in which to pursue improvements in coverage density, temporal variability in the ionosphere, and data quality that promise exciting new discoveries at Mars

Evidence for diversifying selection of genetic regions of encoding putative collagen-like host-adhesive fibers in Pasteuria penetrans

© FEMS 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Pasteuria spp. belong to a group of genetically diverse endospore-forming bacteria (phylum: Firmicutes) that are known to parasitize plant-parasitic nematodes and water fleas (Daphnia spp.). Collagen-like fibres form the nap on the surface of endospores and the genes encoding these sequences have been hypothesised to be involved in the adhesion of the endospores of Pasteuria spp. to their hosts. We report a group of 17 unique collagen-like genes putatively encoded by Pasteuria penetrans (strain: Res148) that formed five different phylogenetic clusters and suggest that collagen-like proteins are an important source of genetic diversity in animal pathogenic Firmicutes including Pasteuria. Additionally, and unexpectedly, we identified a putative collagen-like sequence which had a very different sequence structure to the other collagen-like proteins but was similar to the protein sequences in Megaviruses that are involved in host-parasite interactions. We, therefore, suggest that these diverse endospore surface proteins in Pasteuria are involved in biological functions, such as cellular adhesion; however, they are not of monophyletic origin and were possibly obtained de novo by mutation or possibly through selection acting upon several historic horizontal gene transfer events.Peer reviewedFinal Published versio

Polar layered deposits of Mars as seen by MRO/SHARAD

EGU2007-A-0797

Randomized double-blind placebo-controlled trial of primary maintenance vigil immunotherapy (VITAL study) in stage III/IV ovarian cancer: Efficacy assessment in BRCA1/2-wt patients

6017 Background: Vigil is an autologous tumor cell vaccine constructed from autologous harvested tumor tissue transfected with a DNA plasmid encoding GMCSF and bi-shRNA-furin thereby creating TGFβ expression control. Methods: A randomized double-blind placebo-controlled trial of Vigil vs. placebo was performed in advanced stage frontline OC patients. Relapse-free survival (RFS) and safety were endpoints. Patients who achieved complete clinical response were randomized [1:1 to placebo (control group, CG) or Vigil (Vigil group, VG)] after completion of frontline surgery and chemotherapy. All patients received 1 x 10e7 cells/ml of Vigil or placebo intradermally once a month for up to 12 doses. Results: Ninety-two patients were randomized with 91 patients in the per-protocol population (PP), (VG n=46; CG n=45). 62 patients were tested for BRCA1/2 status. VG showed no added overall toxicity compared to CG and no grade 4/5 toxicities were observed. Grade 2/3 toxic events were observed in 18% of CG patients (most common bone pain, fatigue) compared to 8% of VG patients (most common nausea, musculoskeletal pain). From time of randomization median RFS for all 91 patients was favorable in the VG (HR 0.69, one-sided p 0.088).Stratified by BRCA status, an advantage in RFS was seen in the BRCA1/2-wt patients in VG (19.4 mo) compared to CG (8 mo) (HR 0.51, 90% CI 0.26 – 1.01, one-sided p 0.050) from time of randomization and HR of 0.49 (90% CI 0.25 – 0.97, one-sided p 0.038) from time of surgery. Median time from surgery to randomization was 208.5 days (6.9 mo) in VG vs. 200 days (6.6 mo) in CG. 37.5% BRCA1/2-wt Vigil treated patients relapsed compared to 71% of placebo at time of data snap for analysis (HR 0.51, one-sided p 0.05), (median follow-up of 34.3 mo for all n=91 subjects). Germline and somatic BRCA1/2 molecular testing via central third party is underway on all 91 patients under continued blinded conditions to validate activity in BRCA1/2-wt. Conclusions: Vigil immunotherapy as frontline maintenance in Stage III/IV ovarian cancer is well tolerated and showed RFS clinical benefit, particularly in BRCA1/2-wt disease. Clinical trial information: NCT02346747. [Table: see text