215 research outputs found
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Streaming clumps ejection model and the heterogeneous inner coma of Comet Wild 2
It is modeled that a significant component of the jets of some comets are released as aggregate clumps, which then fragment and shed particles after release, leading to a heterogeneous innermost coma
Non-random spatial distribution of impacts in the Stardust Cometary Collector
We report the discovery that impacts in the Stardust cometary collector are not distributed randomly in the collecting media, but appear to be clustered on scales smaller than ~10 cm
Massive stars in massive clusters - IV. Disruption of clouds by momentum-driven winds
We examine the effect of momentum-driven OB-star stellar winds on a parameter space of simulated turbulent giant molecular clouds using smoothed particle hydrodynamic simulations. By comparison with identical simulations in which ionizing radiation was included instead of winds, we show that momentum-driven winds are considerably less effective in disrupting their host clouds than are Hâii regions. The wind bubbles produced are smaller and generally smoother than the corresponding ionization-driven bubbles. Winds are roughly as effective in destroying the very dense gas in which the O stars are embedded, and thus shutting down the main regions of star-forming activity in the model clouds. However, their influence falls off rapidly with distance from the sources, so they are not as good at sweeping up dense gas and triggering star formation further out in the clouds. As a result, their effect on the star formation rate and efficiency is generally more negative than that of ionization, if they exert any effect at all.Peer reviewe
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The Stardust â a successful encounter with the remarkable comet Wild 2
On January 2, 2004 the Stardust spacecraft completed a close flyby of comet Wild2 (P81). Flying at a relative speed of 6.1 km/s within 237km of the 5 km nucleus, the spacecraft took 72 close-in images, measured the flux of impacting particles and did TOF mass spectrometry
Regulation of immune responses in primary biliary cholangitis: a transcriptomic analysis of peripheral immune cells
BACKGROUND AIMS: In patients with primary biliary cholangitis (PBC), the serum liver biochemistry measured during treatment with ursodeoxycholic acid-the UDCA response-accurately predicts long-term outcome. Molecular characterization of patients stratified by UDCA response can improve biological understanding of the high-risk disease, thereby helping to identify alternative approaches to disease-modifying therapy. In this study, we sought to characterize the immunobiology of the UDCA response using transcriptional profiling of peripheral blood mononuclear cell subsets. METHODS: We performed bulk RNA-sequencing of monocytes and TH1, TH17, TREG, and B cells isolated from the peripheral blood of 15 PBC patients with adequate UDCA response ("responders"), 16 PBC patients with inadequate UDCA response ("nonresponders"), and 15 matched controls. We used the Weighted Gene Co-expression Network Analysis to identify networks of co-expressed genes ("modules") associated with response status and the most highly connected genes ("hub genes") within them. Finally, we performed a Multi-Omics Factor Analysis of the Weighted Gene Co-expression Network Analysis modules to identify the principal axes of biological variation ("latent factors") across all peripheral blood mononuclear cell subsets. RESULTS: Using the Weighted Gene Co-expression Network Analysis, we identified modules associated with response and/or disease status (q<0.05) in each peripheral blood mononuclear cell subset. Hub genes and functional annotations suggested that monocytes are proinflammatory in nonresponders, but antiinflammatory in responders; TH1 and TH17 cells are activated in all PBC cases but better regulated in responders; and TREG cells are activated-but also kept in check-in responders. Using the Multi-Omics Factor Analysis, we found that antiinflammatory activity in monocytes, regulation of TH1 cells, and activation of TREG cells are interrelated and more prominent in responders. CONCLUSIONS: We provide evidence that adaptive immune responses are better regulated in patients with PBC with adequate UDCA response
Regulation of immune responses in primary biliary cholangitis: a transcriptomic analysis of peripheral immune cells
Copyright \ua9 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.Background & Aims: In patients with primary biliary cholangitis (PBC), the serum liver biochemistry measured during treatment with ursodeoxycholic acid-the UDCA response-accurately predicts long-term outcome. Molecular characterization of patients stratified by UDCA response can improve biological understanding of the high-risk disease, thereby helping to identify alternative approaches to disease-modifying therapy. In this study, we sought to characterize the immunobiology of the UDCA response using transcriptional profiling of peripheral blood mononuclear cell subsets. Methods: We performed bulk RNA-sequencing of monocytes and TH1, TH17, TREG, and B cells isolated from the peripheral blood of 15 PBC patients with adequate UDCA response (ârespondersâ), 16 PBC patients with inadequate UDCA response (ânonrespondersâ), and 15 matched controls. We used the Weighted Gene Co-expression Network Analysis to identify networks of co-expressed genes (âmodulesâ) associated with response status and the most highly connected genes (âhub genesâ) within them. Finally, we performed a Multi-Omics Factor Analysis of the Weighted Gene Co-expression Network Analysis modules to identify the principal axes of biological variation (âlatent factorsâ) across all peripheral blood mononuclear cell subsets. Results: Using the Weighted Gene Co-expression Network Analysis, we identified modules associated with response and/or disease status (q < 0.05) in each peripheral blood mononuclear cell subset. Hub genes and functional annotations suggested that monocytes are proinflammatory in nonresponders, but antiinflammatory in responders; TH1 and TH17 cells are activated in all PBC cases but better regulated in responders; and TREG cells are activated-but also kept in check-in responders. Using the Multi-Omics Factor Analysis, we found that antiinflammatory activity in monocytes, regulation of TH1 cells, and activation of TREG cells are interrelated and more prominent in responders. Conclusions: We provide evidence that adaptive immune responses are better regulated in patients with PBC with adequate UDCA response
Regulation of immune responses in primary biliary cholangitis: a transcriptomic analysis of peripheral immune cells
BACKGROUND AIMS: In patients with primary biliary cholangitis (PBC), the serum liver biochemistry measured during treatment with ursodeoxycholic acid-the UDCA response-accurately predicts long-term outcome. Molecular characterization of patients stratified by UDCA response can improve biological understanding of the high-risk disease, thereby helping to identify alternative approaches to disease-modifying therapy. In this study, we sought to characterize the immunobiology of the UDCA response using transcriptional profiling of peripheral blood mononuclear cell subsets. METHODS: We performed bulk RNA-sequencing of monocytes and TH1, TH17, TREG, and B cells isolated from the peripheral blood of 15 PBC patients with adequate UDCA response ("responders"), 16 PBC patients with inadequate UDCA response ("nonresponders"), and 15 matched controls. We used the Weighted Gene Co-expression Network Analysis to identify networks of co-expressed genes ("modules") associated with response status and the most highly connected genes ("hub genes") within them. Finally, we performed a Multi-Omics Factor Analysis of the Weighted Gene Co-expression Network Analysis modules to identify the principal axes of biological variation ("latent factors") across all peripheral blood mononuclear cell subsets. RESULTS: Using the Weighted Gene Co-expression Network Analysis, we identified modules associated with response and/or disease status (q<0.05) in each peripheral blood mononuclear cell subset. Hub genes and functional annotations suggested that monocytes are proinflammatory in nonresponders, but antiinflammatory in responders; TH1 and TH17 cells are activated in all PBC cases but better regulated in responders; and TREG cells are activated-but also kept in check-in responders. Using the Multi-Omics Factor Analysis, we found that antiinflammatory activity in monocytes, regulation of TH1 cells, and activation of TREG cells are interrelated and more prominent in responders. CONCLUSIONS: We provide evidence that adaptive immune responses are better regulated in patients with PBC with adequate UDCA response
Sport and physical activity in the lives of looked-after children: a âhidden groupâ in research, policy and practice
Looked-after children are arguably one of the most disadvantaged groups in society and constitute a âhidden groupâ in relation to sport and physical activity research, policy and practice. Research on looked-after children has explored the views of caregivers, practitioners and policy-makers who have often been asked to speak for children on their behalf. Through the use of the mosaic approach and innovative participatory methods, including peer interviewing, the purpose of this paper was to provide an insight into a new area of research in the field of sport and physical activity. As such, it reports on initial findings from a wider project with looked-after children that explores their sport and physical activity experiences. Specifically, it asks the following: (1) What are the sport and physical activity experiences of looked-after children? (2) What meanings and values do looked-after children ascribe to their engagement in sport and physical activity? Findings from the voices of four male looked-after children highlight that these young people used sport as a means to an end; to spend time with friends and develop stocks of social capital. However, due to changes in placement, they also experienced disrupted patterns of engagement coupled with additional institutional constraints that shaped access to sporting activities
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