Drogue Parachute Computational Structural and Fluid Mechanics Analysis with Isogeometric Discretization

During the Orion spacecraft’s return, at higher altitudes drogue parachutes will be used for deceleration. These parachutes are made of ribbons and have 24 gores, with 52 ribbons in each gore, where a gore is the slice of the parachute between two radial reinforcement cables extending from the parachute apex to the skirt. There are hundreds of gaps that the flow goes through, and there are also three wider gaps created by removing ribbons. Computational analysis can help reduce the number of costly drop tests in comprehensive evaluation of the parachute performance. Reliable analysis requires accurate computation of the parachute fluid-structure interaction (FSI) between the drogue and the compressible flow it is subjected to. The FSI computation is challenging because of the geometric and flow complexities and requires first creation of a starting parachute shape and flow field. This is a process that by itself is rather challenging, and that is what we are focusing on here. In our structural and fluid mechanics computations, for spatial discretization, we use isogeometric discretization with quadratic NURBS basis functions. This gives us a parachute shape that is smoother than what we get from a typical finite element discretization. In the flow analysis, we use the NURBS basis functions in the context of the compressible-flow Space-Time SUPG (ST SUPG) method. The combination of the ST framework, NURBS basis functions, and the SUPG stabilization assures superior computational accuracy

Imaging Redshift Estimates for BL Lacertae Objects

We have obtained high dynamic range, good natural seeing i' images of BL Lacertae objects (BL Lacs) to search for the AGN host and thus constrain the source redshift. These objects are drawn from a sample of bright flat-spectrum radio sources that are either known (via recent Fermi LAT observations) gamma-ray emitters or similar sources that might be detected in continuing gamma-ray observations. All had spectroscopic confirmation as BL Lac sources, but no redshift solution. We detected hosts for 25/49 objects. As these galaxies have been argued to be standard candles, our measured host magnitudes provide redshift estimates (ranging from 0.2--1.0). Lower bounds are established on the redshifts of non-detections. The mean of the fit redshifts (and lower limits) is higher than those of spectroscopic solutions in the radio- and gamma-ray- loud parent samples, suggesting corrections may be needed for the luminosity function and evolution of these sources.Comment: 15 pages, to appear in the Astrophysical Journa

Meta-Mass Shift Chemical (MeMSChem) profiling of metabolomes from coral reefs

Untargeted metabolomics of environmental samples routinely detects thousands of small molecules, the vast majority of which cannot be identified. Meta-mass shift chemical (MeMSChem) profiling was developed to identify mass differences between related molecules using molecular networks. This approach illuminates metabolome-wide relationships between molecules and the putative chemical groups that differentiate them (e.g., H2, CH2, COCH2). MeMSChem profiling was used to analyze a publicly available metabolomic dataset of coral, algal, and fungal mat holobionts (i.e., the host and its associated microbes and viruses) sampled from some of Earth's most remote and pristine coral reefs. Each type of holobiont had distinct mass shift profiles, even when the analysis was restricted to molecules found in all samples. This result suggests that holobionts modify the same molecules in different ways and offers insights into the generation of molecular diversity. Three genera of stony corals had distinct patterns of molecular relatedness despite their high degree of taxonomic relatedness. MeMSChem profiles also partially differentiated between individuals, suggesting that every coral reef holobiont is a potential source of novel chemical diversity

Busulphan is active against neuroblastoma and medulloblastoma xenografts in athymic mice at clinically achievable plasma drug concentrations

High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity. The highest bioavailability was obtained with busulphan in DMSO administered i.p. When busulphan was suspended in carboxymethylcellulose and given orally or i.p., the bioavailability was poor. Then, in the therapeutic experiments, busulphan in DMSO was administered i.p. on days 0 and 4. At the maximum tolerated total dose (50 mg kg−1), busulphan induced a significant tumour growth delay, ranging from 12 to 34 days in the three neuroblastomas evaluated and in one out of three medulloblastomas. At a dose level above the maximum tolerated dose, busulphan induced complete and partial tumour regressions. Busulphan was inactive in a peripheral primitive neuroectodermal tumour (PNET) xenograft. When busulphan pharmacokinetics in mice and humans were considered, the estimated systemic exposure at the therapeutically active dose in mice (113 μg h ml−1) was close to the mean total systemic exposure in children receiving high-dose busulphan (102.4 μg h ml−1). In conclusion, busulphan displayed a significant anti-tumour activity in neuroblastoma and medulloblastoma xenografts at plasma drug concentrations which can be achieved clinically in children receiving high-dose busulphan-containing regimens. 1999 Cancer Research Campaig

Catching Element Formation In The Act

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts