2,739 research outputs found
Observations and three-dimensional ionization structure of the planetary nebula SuWt 2
The planetary nebula SuWt 2 (PN G311.0+02.4), is an unusual object with a
prominent, inclined central emission ellipse and faint bipolar extensions. It
has two A-type stars in a proven binary system at the centre. However, the
radiation from these two central stars is too soft to ionize the surrounding
material leading to a so far fruitless search for the responsible ionizing
source. Such a source is clearly required and has already been inferred to
exist via an observed temporal variation of the centre-of-mass velocity of the
A-type stars. Moreover, the ejected nebula is nitrogen-rich which raises
question about the mass-loss process from a likely intermediate-mass
progenitor. We use optical integral-field spectroscopy to study the emission
lines of the inner nebula ring. This has enabled us to perform an empirical
analysis of the optical collisionally excited lines, together with a fully
three-dimensional photoionization modelling. Our empirical results are used to
constrain the photoionization models, which determine the evolutionary stage of
the responsible ionizing source and its likely progenitor. The time-scale for
the evolutionary track of a hydrogen-rich model atmosphere is inconsistent with
the dynamical age obtained for the ring. This suggests that the central star
has undergone a very late thermal pulse. We conclude that the ionizing star
could be hydrogen-deficient and compatible with what is known as a PG 1159-type
star. The evolutionary tracks for the very late thermal pulse models imply a
central star mass of ~ 0.64M, which originated from a ~
3M progenitor. The evolutionary time-scales suggest that the
central star left the asymptotic giant branch about 25,000 years ago, which is
consistent with the nebula's age.Comment: 18 pages, 11 figures, 10 tables, proof corrections applie
NWSA NEWS AND VIEWS
FROM THE STEERING COMMITTEE
Responding to the 1979 charge of the Finance Committee and the Delegate Assembly, the Coordinating Council devoted a major portion of its February 14-17 meeting in College Park to a discussion of finances. The clear intent of all sessions was the consideration of fiscal responsibility in terms of feminist principles and the goals of NWSA.
On February 13, several members of the 1979-80 Finance Committee (Liz Birch, Alice Stadthaus, Barbara Taylor, Mary Thornberry, and Robin Wright) met with the Steering Committee (Pat Gozemba, Jan Meriwether, and Kay Towns); the National Coordinator, Elaine Reuben; the National Staff Associate, Donna Whittlesey; and consultants from Women\u27s Resources of Philadelphia. At that time they planned means for addressing financial issues at the CC meeting
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Wnt5a induces ROR1 to recruit cortactin to promote breast-cancer migration and metastasis.
ROR1 is a conserved oncoembryonic surface protein expressed in breast cancer. Here we report that ROR1 associates with cortactin in primary breast-cancer cells or in MCF7 transfected to express ROR1. Wnt5a also induced ROR1-dependent tyrosine phosphorylation of cortactin (Y421), which recruited ARHGEF1 to activate RhoA and promote breast-cancer-cell migration; such effects could be inhibited by cirmtuzumab, a humanized mAb specific for ROR1. Furthermore, treatment of mice bearing breast-cancer xenograft with cirmtuzumab inhibited cortactin phosphorylation in vivo and impaired metastatic development. We established that the proline at 841 of ROR1 was required for it to recruit cortactin and ARHGEF1, activate RhoA, and enhance breast-cancer-cell migration in vitro or development of metastases in vivo. Collectively, these studies demonstrate that the interaction of ROR1 with cortactin plays an important role in breast-cancer-cell migration and metastasis
NWSA News and Views
The reports in this issue on the finances of the First NWSA Convention and on NWSA\u27s Project to Improve Service Learning in Women\u27s Studies might serve as Fall reports from the National Office.
Both are about NWSA activities derived from our broad definition of women\u27s studies; both announce long-awaited good news of what we hope will be the first of many successful conventions and projects that will bring women\u27s studies practitioners together to share the work of transforming curriculum and educational institutions
Analysis of Surface Charging for a Candidate Solar Sail Mission Using NASCAP-2K
The characterization of the electromagnetic interaction for a solar sail in the solar wind environment and identification of viable charging mitigation strategies are critical solar sail mission design tasks. Spacecraft charging has important implications both for science applications and for lifetime and reliability issues of sail propulsion systems. To that end, surface charging calculations of a candidate 150-meter-class solar sail spacecraft for the 0.5 AU solar polar and 1.9 AU LI solar wind environments are performed. A model of the spacecraft with candidate materials having appropriate electrical properties is constructed using Object Toolkit. The spacecraft charging analysis is performed using Nascap-2k. the NASA/AFRL sponsored spacecraft charging analysis tool. Nominal and atypical solar wind environments appropriate for the 0.5 AU and 1.0 AU missions are used to establish current collection of solar wind ions and electrons. Finally, a geostationary orbit environment case is included to demonstrate a bounding example of extreme (negative) charging of a solar sail spacecraft. Results from the charging analyses demonstrate that minimal differential potentials (and resulting threat of electrostatic discharge) occur when the spacecraft is constructed entirely of conducting materials, as anticipated from standard guidelines for mitigation of spacecraft charging issues. Examples with dielectric materials exposed to the space environment exhibit differential potentials ranging from a few volts to extreme potentials in the kilovolt range
Detection rate of actionable mutations in diverse cancers using a biopsy-free (blood) circulating tumor cell DNA assay.
Analysis of cell-free DNA using next-generation sequencing (NGS) is a powerful tool for the detection/monitoring of alterations present in circulating tumor DNA (ctDNA). Plasma extracted from 171 patients with a variety of cancers was analyzed for ctDNA (54 genes and copy number variants (CNVs) in three genes (EGFR, ERBB2 and MET)). The most represented cancers were lung (23%), breast (23%), and glioblastoma (19%). Ninety-nine patients (58%) had at least one detectable alteration. The most frequent alterations were TP53 (29.8%), followed by EGFR (17.5%), MET (10.5%), PIK3CA (7%), and NOTCH1 (5.8%). In contrast, of 222 healthy volunteers, only one had an aberration (TP53). Ninety patients with non-brain tumors had a discernible aberration (65% of 138 patients; in 70% of non-brain tumor patients with an alteration, the anomaly was potentially actionable). Interestingly, nine of 33 patients (27%) with glioblastoma had an alteration (6/33 (18%) potentially actionable). Overall, sixty-nine patients had potentially actionable alterations (40% of total; 69.7% of patients (69/99) with alterations); 68 patients (40% of total; 69% of patients with alterations), by a Food and Drug Administration (FDA) approved drug. In summary, 65% of diverse cancers (as well as 27% of glioblastomas) had detectable ctDNA aberration(s), with the majority theoretically actionable by an approved agent
A Framework for Targeting Water, Sanitation and Hygiene Interventions in Pastoralist Populations in the Afar Region of Ethiopia
Globally, many populations face structural and environmental barriers to access safe water, sanitation and hygiene (WASH) services. Among these populations are many of the 200 million pastoralists whose livelihood patterns and extreme environmental settings challenge conventional WASH programming approaches. In this paper, we studied the Afar pastoralists in Ethiopia to identify WASH interventions that can mostly alleviate public health risks, within the population's structural and environmental living constraints. Surveys were carried out with 148 individuals and observational assessments made in 12 households as part of a Pastoralist Community WASH Risk Assessment. The results show that low levels of access to infrastructure are further compounded by risky behaviours related to water containment, storage and transportation. Additional behavioural risk factors were identified related to sanitation, hygiene and animal husbandry. The Pastoralist Community WASH Risk Assessment visually interprets the seriousness of the risks against the difficulty of addressing the problem. The assessment recommends interventions on household behaviours, environmental cleanliness, water storage, treatment and hand hygiene via small-scale educational interventions. The framework provides an approach for assessing risks in other marginal populations that are poorly understood and served through conventional approaches
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Neutrophil extracellular trap formation is elicited in response to cold physical plasma
Cold physical plasma is an ionized gas with a multitude of components, including hydrogen peroxide and other reactive oxygen and nitrogen species. Recent studies suggest that exposure of wounds to cold plasma may accelerate healing. Upon wounding, neutrophils are the first line of defense against invading microorganisms but have also been identified to play a role in delayed healing. In this study, we examined how plasma treatment affects the functions of peripheral blood neutrophils. Plasma treatment induced oxidative stress, as assessed by the oxidation of intracellular fluorescent redox probes; reduced metabolic activity; but did not induce early apoptosis. Neutrophil oxidative burst was only modestly affected after plasma treatment, and the killing of Pseudomonas aeruginosa and Staphylococcus aureus was not significantly affected. Intriguingly, we found that plasma induced profound extracellular trap formation. This was inhibited by the presence of catalase during plasma treatment but was not replicated by adding an equivalent concentration of hydrogen peroxide. Plasma-induced neutrophil extracellular trap formation was not dependent on the activity of myeloperoxidase or NADPH oxidase 2 but seemed to involve short-lived molecules. The amount of DNA release and the time course after plasma treatment were similar to that with the common neutrophil extracellular trap inducer PMA. After neutrophil extracellular traps had formed, concentrations of IL-8 were also significantly increased in supernatants of plasma-treated neutrophils. Both neutrophil extracellular traps and IL-8 release may aid antimicrobial activity and spur inflammation at the wound site. Whether this aids or exacerbates wound healing needs to be tested
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