50 research outputs found

    Can Acute Galactic Cosmic Radiation-Induced Bone Loss Be Mitigated By Dietary Modulation Of Inflammatory Cytokines?

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    The space environment includes weightlessness and galactic cosmic radiation (GCR), both of which can have a negative impact on bone parameters. In particular, acute exposures to space-relevant doses (2 Gy or less) of simulated GCR lead to a rapid acceleration of bone resorption activity and suppression of bone forming osteoblasts, resulting in diminished bone mineral density (BMD), strength and altered microarchitecture. A key mechanism driving these changes may be a radiation-induced increase in pro-inflammatory cytokines, such as TNF-α. Consuming a diet rich in omega-3 fatty acids has been associated with attenuated reductions in bone parameters in astronauts, mice and elderly humans with corresponding reductions in circulating inflammatory cytokines. PURPOSE: To test the hypothesis thata diet high in omega-3 fatty acids will mitigate radiation-induced bone loss and reduce inflammatory cytokines in bone osteocytes and serum. METHODS: Adult (30- to 50-week-old) female Lgr5-EGFP C57BL/6 mice (n=4-6 per group) were acclimated to a corn oil/cellulose (COC) or fish oil/pectin (FOP) diet for 3 weeks. Animals were subsequently randomized to total body low dose high-energy radiation (0.1, 0.25, 0.5 Gy of 1000 MeV/n 56Fe at 25 cGy/min at Brookhaven National Lab) or non-irradiated control (sham) and euthanized 8 weeks later. MicroCT (ScanCo, Switzerland) analyses were performed to assess bone geometry and microarchitecture at the mid-shaft and distal end of the femur. Significance was assessed using an αof 0.10. RESULTS:There was a significant main effect of diet on mid-shaft femur periosteal diameter (Peri.Dm) (p=0.001) and endocortical diameter (Endo. Dm.) (p\u3c0.001). The FOP diet led to larger Peri.Dm. (p\u3c0.051 for all) and Endo.Dm. (p\u3c0.41 for all) than did the COC diet at all doses. We could not detect an impact of 56Fe on cortical area or cancellous bone volume at the distal femur. Irradiation with 0.25 and 0.5 Gy in the FOP mice showed significant increases in distal femur volumetric BMD (p=0.014, p=0.063) and trabecular thickness (p=0.058, p=0.028), as compared with sham FOP mice. CONCLUSION: Though we did not detect a significant impact of radiation on bone parameters, these early data analyses suggest some modest benefits from a diet high in omega-3 fatty acids on cortical and cancellous bone parameters

    The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background

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    We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15-year pulsar-timing data set collected by the North American Nanohertz Observatory for Gravitational Waves. The correlations follow the Hellings-Downs pattern expected for a stochastic gravitational-wave background. The presence of such a gravitational-wave background with a power-law-spectrum is favored over a model with only independent pulsar noises with a Bayes factor in excess of 101410^{14}, and this same model is favored over an uncorrelated common power-law-spectrum model with Bayes factors of 200-1000, depending on spectral modeling choices. We have built a statistical background distribution for these latter Bayes factors using a method that removes inter-pulsar correlations from our data set, finding p=103p = 10^{-3} (approx. 3σ3\sigma) for the observed Bayes factors in the null no-correlation scenario. A frequentist test statistic built directly as a weighted sum of inter-pulsar correlations yields p=5×1051.9×104p = 5 \times 10^{-5} - 1.9 \times 10^{-4} (approx. 3.54σ3.5 - 4\sigma). Assuming a fiducial f2/3f^{-2/3} characteristic-strain spectrum, as appropriate for an ensemble of binary supermassive black-hole inspirals, the strain amplitude is 2.40.6+0.7×10152.4^{+0.7}_{-0.6} \times 10^{-15} (median + 90% credible interval) at a reference frequency of 1/(1 yr). The inferred gravitational-wave background amplitude and spectrum are consistent with astrophysical expectations for a signal from a population of supermassive black-hole binaries, although more exotic cosmological and astrophysical sources cannot be excluded. The observation of Hellings-Downs correlations points to the gravitational-wave origin of this signal.Comment: 30 pages, 18 figures. Published in Astrophysical Journal Letters as part of Focus on NANOGrav's 15-year Data Set and the Gravitational Wave Background. For questions or comments, please email [email protected]

    The Development of the Rheumatology Informatics System for Effectiveness Learning Collaborative for Improving Patient-Reported Outcome Collection and Patient-Centered Communication in Adult Rheumatology.

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    ObjectivePatient-reported outcomes (PROs) are an integral part of treat-to-target approaches in managing rheumatoid arthritis (RA). In clinical practice, however, routine collection, documentation, and discussion of PROs with patients are highly variable. The RISE LC (Rheumatology Informatics System for Effectiveness Learning Collaborative) was established to develop and share best practices in PRO collection and use across adult rheumatology practices in the United States METHODS: The goals of the RISE LC were developed through site surveys and in-person meetings. Participants completed a baseline survey on PRO collection and use in their practices. RISE LC learning sessions focused on improving communication around PROs with patients and enhancing shared decision-making in treatment plans. During the coronavirus disease 2019 (COVID-19) pandemic, the RISE LC pivoted to adapt PRO tools for telehealth.ResultsAt baseline, all responding sites (n = 15) had established workflows for collecting PROs. Most sites used paper forms alone. PRO documentation in electronic health records was variable, with only half of the sites using structured data fields. To standardize and improve the use of PROs, participants iteratively developed a Clinical Disease Activity Index-based RA Disease Activity Communication Tool to solicit treatment goals and improve shared decision-making across sites. The COVID-19 pandemic necessitated developing a tool to gauge PROs via telehealth.ConclusionThe RISE LC is a continuous, structured method for implementing strategies to improve PRO collection and use in rheumatological care, initially adapting from the Learning Collaborative model and extending to include features of a learning network. Future directions include measuring the impact of standardized PRO collection and discussion on shared decision-making and RA outcomes

    A complex dynamo inferred from the hemispheric dichotomy of Jupiter’s magnetic field

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    The Juno spacecraft, which is in a polar orbit around Jupiter, is providing direct measurements of the planet’s magnetic field close to its surface. A recent analysis of observations of Jupiter’s magnetic field from eight (of the first nine) Juno orbits has provided a spherical-harmonic reference model (JRM09) of Jupiter’s magnetic field outside the planet. This model is of particular interest for understanding processes in Jupiter’s magnetosphere, but to study the field within the planet and thus the dynamo mechanism that is responsible for generating Jupiter’s main magnetic field, alternative models are preferred. Here we report maps of the magnetic field at a range of depths within Jupiter. We find that Jupiter’s magnetic field is different from all other known planetary magnetic fields. Within Jupiter, most of the flux emerges from the dynamo region in a narrow band in the northern hemisphere, some of which returns through an intense, isolated flux patch near the equator. Elsewhere, the field is much weaker. The non-dipolar part of the field is confined almost entirely to the northern hemisphere, so there the field is strongly non-dipolar and in the southern hemisphere it is predominantly dipolar. We suggest that Jupiter’s dynamo, unlike Earth’s, does not operate in a thick, homogeneous shell, and we propose that this unexpected field morphology arises from radial variations, possibly including layering, in density or electrical conductivity, or both
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