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476 results on '"Russell, David G."'

10. The frequency of CD38+ alveolar macrophages correlates with early control of M. tuberculosis in the murine lung.

Author

Pisu, Davide, Johnston, Luana, Mattila, Joshua T., and Russell, David G.

Subjects
ALVEOLAR macrophages, MYCOBACTERIUM tuberculosis, MYCOBACTERIAL diseases, BCG vaccines, BACTERIAL growth
Abstract

Tuberculosis, caused by Mycobacterium tuberculosis, remains an enduring global health challenge due to the limited efficacy of existing treatments. Although much research has focused on immune failure, the role of host macrophage biology in controlling the disease remains underappreciated. Here we show, through multi-modal single-cell RNA sequencing in a murine model, that different alveolar macrophage subsets play distinct roles in either advancing or controlling the disease. Initially, alveolar macrophages that are negative for the CD38 marker are the main infected population. As the infection progresses, CD38+ monocyte-derived and tissue-resident alveolar macrophages emerge as significant controllers of bacterial growth. These macrophages display a unique chromatin organization pre-infection, indicative of epigenetic priming for pro-inflammatory responses. Moreover, intranasal BCG immunization increases the numbers of CD38+ macrophages, enhancing their capability to restrict Mycobacterium tuberculosis growth. Our findings highlight the dynamic roles of alveolar macrophages in tuberculosis and open pathways for improved vaccines and therapies. Mycobacterium tuberculosis infection remains a global health crisis. Here researchers characterise the alveolar macrophage subsets in a murine model of BCG vaccination in mice and link increases of CD38+ macrophages with restriction of bacterial growth. [ABSTRACT FROM AUTHOR]

Published
2024
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12. The Tuberculosis Drug Accelerator at year 10: what have we learned?

Author

Aldridge, Bree B., Barros-Aguirre, David, Barry, III, Clifton E., Bates, Robert H., Berthel, Steven J., Boshoff, Helena I., Chibale, Kelly, Chu, Xin-Jie, Cooper, Christopher B., Dartois, Véronique, Duncan, Ken, Fotouhi, Nader, Gusovsky, Fabian, Hipskind, Philip A., Kempf, Dale J., Lelièvre, Joël, Lenaerts, Anne J., McNamara, Case W., Mizrahi, Valerie, Nathan, Carl, Olsen, David B., Parish, Tanya, Petrassi, H. Michael, Pym, Alexander, Rhee, Kyu Y., Robertson, Gregory T., Rock, Jeremy Michael, Rubin, Eric J., Russell, Betsy, Russell, David G., Sacchettini, James C., Schnappinger, Dirk, Schrimpf, Michael, Upton, Anna M., Warner, Peter, Wyatt, Paul Graham, and Yuan, Ying

Published
2021
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20. The New Anglo-Saxons: Race, Space, and the Production of a Geopolitical Discourse.

Author

Russell, David G. and Radil, Steven M.

Subjects
*GEOPOLITICS, *CRITICAL discourse analysis, *ARCHIVAL materials
Abstract

The question of how individuals produce and reproduce geopolitical ideologies is central to critical geopolitics, but there is little consensus on how this process works or what methods can meaningfully interrogate it. This article brings together methods from critical geopolitics, history, and sociolinguistics to assess the development, dissemination, and trajectory of Anglo-Saxonism, a late-nineteenth century movement which sought to unite the white English-speaking peoples of the world based on the racial heritage and democratic socio-political institutions they allegedly shared. We investigate the archival material of two prominent historians central to this movement—E.A. Freeman and H.B. Adams—to examine their own statements about their work, introducing the concept of "geopolitical metanarratives" to link between intention and discourse. We find that as Freeman and Adams intentionally worked to advance the movement, they relied on a spatial imagination that emphasized the historical continuity of socio-political institutions as the key racialized geopolitical metanarrative that served to underpin their efforts. [ABSTRACT FROM AUTHOR]

Published
2024
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22. A sub-Saturn Mass-Radius Desert for Planets with Equilibrium Temperature Less than 600 K

Author

Russell, David G.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

The sample of exoplanets from the NASA Exoplanet Archive with equilibrium temperature less than 600 K and with low uncertainty for both mass and radius measurements is found to have a desert in the mass-radius distribution consistent with predictions from the core-accretion scenario. This sub-Saturn mass-radius desert is almost completely barren of any planets with both a mass greater than 20 Earth masses and a radius in the range 4.0 to 7.5 Earth radii for the sample of planets with equilibrium temperature less than 600 K. In contrast, the sample of planets with equilibrium temperature greater than 630 K includes a large fraction of planets with mass-radius values that fall into the less than 600 K sub-Saturn mass-radius desert. The difference between the two populations may result from differences in migration history in the core-accretion scenario., 9 pages, 2 figures, submitted to Icarus

Published
2023

27. A Catalog of Exoplanets with Equilibrium Temperature less than 600 K

Author

Russell, David G.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Earth and Planetary Astrophysics
Abstract

The NASA Exoplanet Archive was searched for planets with an equilibrium temperature below 600 K, mass uncertainty less than 27 percent, and radius uncertainty less than 8 percent. This search produced 93 planets with mass from 0.3 to 1680 ME; and 101 planets if the Solar System planets are included. The characteristics of the sample in this catalog are: (1) 94 percent of the Terrestrial planets have mass less than 2.9 ME and radius less than 1.4 RE, (3) The sample has a small drop in population consistent with the previously identified radius gap from 1.5 to 2.0 RE, (4) Planets in the radius range 1.50 to 2.25 RE are consistent with either a gas-rich Terrestrial composition or a rock-ice Terrestrial composition with a supercritical hydrosphere and water mass fraction less than 20 percent, (5) A super-Neptune radius desert is observed for the radius range 4.5 to 7.5 RE, (6) Saturn composition planets have masses from 15 to 170 ME and radii from 7.9 to 10.1 RE, (7) A nearly barren sub-Saturn mass-radius desert is found in the sample as indicated by a lack of planets with mass exceeding 20 ME and radii in the range 4.0 to 7.5 RE, (8) Most Jupiter composition planets have radii between 10.9 and 12.4 RE and mass exceeding 200 ME, (9) With few exceptions, planet radius can be used as a proxy for planet composition classification into Terrestrial, gas-rich Terrestrial or supercritical hydrosphere Terrestrial, Rock-Ice Giant, and Gas Giant composition classes for this sample of Teq less than 600 K planets. The characteristics of this sample are consistent with several predictions of the core accretion model including the predicted values for the critical core mass for gas accretion and runaway accretion, the pebble isolation mass, and the Saturn mass desert., 27 pages, 11 tables, 3 figures, comments welcome

Published
2023

29. Investigation into the Mechanism of Action of the Tuberculosis Drug Candidate SQ109 and Its Metabolites and Analogues in Mycobacteria.

Author

Malwal, Satish R., Mazurek, Ben, Ko, Jihee, Xie, Pujun, Barnes, Chikako, Varvitsiotis, Christine, Zimmerman, Matthew D., Olatunji, Samir, Lee, Jaeyong, Xie, Min, Sarathy, Jansy, Caffrey, Martin, Strynadka, Natalie C. J., Dartois, Véronique, Dick, Thomas, Lee, Bom Nae Rin, Russell, David G., and Oldfield, Eric

Published
2023
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30. Introducing the Spatial Conflict Dynamics Indicator of Political Violence.

Author

Walther, Olivier J., Radil, Steven M., Russell, David G., and Trémolières, Marie

Subjects
BIG data, VIOLENCE, GEOGRAPHY
Abstract

While the location of violent events and their propensity to cluster together in space is increasingly well known, a deeper exploration of their spatiality and spatial evolution over time remains an emerging frontier in "Big Data"-driven conflict studies. The new Spatial Conflict Dynamics indicator (SCDi) introduced in this article contributes to fill this gap, by measuring both the intensity and spatial concentration of political violence at the subnational level. Articulating between point pattern and areal spatial analyses, the SCDi allows conflict researchers and analysts to not just map which regions experience the most violence but to track how the geography of conflict evolves over time. The SCDi identifies four spatial typologies of violence and can leverage political event data from most datasets with locational information and can be used for analyses across large multi-state regions, within a single state, or in more localized contexts. In this paper, we illustrate the SCDi with an application to the case of North and West Africa, analyzing over 30,000 discrete events through a twenty-two-year time span and across a twenty-two-state geographical area. We perform a longitudinal analysis of the SCDi typologies to show how the indicator can inform a theory of the spatial lifecycle of violence in the region. The indicator, therefore, has potential as both an analytic tool and a window on conflict episodes, showing how they can change from conflict initiation through resolution. [ABSTRACT FROM AUTHOR]

Published
2023
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