Browsing by Author "Lawrence, Chris"

Now showing 1 - 5 of 5
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    A computational model of invasive aspergillosis in the lung and the role of iron
    Oremland, Matthew; Michels, Kathryn R.; Bettina, Alexandra M.; Lawrence, Chris; Mehrad, Borna; Laubenbacher, Reinhard C. (BMC, 2016)
    Background: Invasive aspergillosis is a severe infection of immunocompromised hosts, caused by the inhalation of the spores of the ubiquitous environmental molds of the Aspergillus genus. The innate immune response in this infection entails a series of complex and inter-related interactions between multiple recruited and resident cell populations with each other and with the fungal cell; in particular, iron is critical for fungal growth. Results: A computational model of invasive aspergillosis is presented here; the model can be used as a rational hypothesis-generating tool to investigate host responses to this infection. Using a combination of laboratory data and published literature, an in silico model of a section of lung tissue was generated that includes an alveolar duct, adjacent capillaries, and surrounding lung parenchyma. The three-dimensional agent-based model integrates temporal events in fungal cells, epithelial cells, monocytes, and neutrophils after inhalation of spores with cellular dynamics at the tissue level, comprising part of the innate immune response. Iron levels in the blood and tissue play a key role in the fungus’ ability to grow, and the model includes iron recruitment and consumption by the different types of cells included. Parameter sensitivity analysis suggests the model is robust with respect to unvalidated parameters, and thus is a viable tool for an in silico investigation of invasive aspergillosis. Conclusions: Using laboratory data from a mouse model of invasive aspergillosis in the context of transient neutropenia as validation, the model predicted qualitatively similar time course changes in fungal burden, monocyte and neutrophil populations, and tissue iron levels. This model lays the groundwork for a multi-scale dynamic mathematical model of the immune response to Aspergillus species.
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    Deep Tillage Prior to No-Till Corn: Research and Recommendations
    Thomason, Wade E.; Grisso, Robert D.; Balderson, T. Keith; Davis, Paul H.; Johnson, Sam; Lawrence, Chris; Lewis, Matthew A.; Moore, David M.; Alley, Marcus M. (Virginia Cooperative Extension, 2019-03-29)
    Compares cultivation of corn by no-till and deep tillage and notes ways to reduce soil compaction, using deep tillage if soil compaction has effected crop growth and yield.
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    Deep Tillage Prior to No-Till Corn: Research and Recommendations
    Thomason, Wade E.; Grisso, Robert D.; Balderson, T. Keith; Davis, Paul H.; Johnson, Sam; Lawrence, Chris; Lewis, Matthew A.; Moore, David M.; Alley, Marcus M. (Virginia Cooperative Extension, 2009)
    Compares cultivation of corn by no-till and deep tillage and notes ways to reduce soil compaction, using deep tillage if soil compaction has effected crop growth and yield.
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    Promotion and Adoption of Soil Health in Virginia: The Power of a Simple Demonstration and Story
    Bendfeldt, Eric S.; Thomason, Wade E.; Niewolny, Kimberly L.; Parrish, Michael J.; Lawrence, Chris; Holm, Kathy (2019-07-17)
    Soil is a foundational resource for farming, natural resource conservation, and health in the 21st century. Virginia farmers have made significant progress in protecting and conserving natural resources. Controlling soil loss and nutrient runoff — non-point source pollution — from all possible sources continues to be critical for water quality protection and clean-up efforts throughout Virginia and the Chesapeake Bay Watershed. The current emphasis on soil health encourages an integrated holistic, systemic approach to soil management. Soil health principles bring to light the importance of soil organic matter (SOM), carbon, fungi, bacteria, and soil insects as key drivers to the system and integral for building and enhancing soil’s physical and chemical properties. Virginia Tech, Virginia Cooperative Extension, Virginia USDA-Natural Resources Conservation Service, along with community partners, have worked to find common ground around a similar educational message for agricultural professionals, technical service providers, and the farming community. The message emphasizes soil as a living ecosystem and the need to care for the soil's biological properties as well as the physical and chemical properties. Simple in-class and on-farm demonstrations (i.e., slake test, rainfall simulator) and stories of farmers’ experiences (i.e., through panels, short videos and technical clips) are powerful in promoting and encouraging the adoption of core soil health principles in Virginia. The power of a simple demonstration and story complements on-going research and demonstration efforts while enabling outreach to a broader educational audience. For example, a rainfall simulator demonstration at the Shenandoah Valley Produce Auction’s Annual Membership meeting enabled Virginia Cooperative Extension and Virginia USDA-NRCS to reach not only 120 farmers within a Mennonite community with a soil health message but also women, youth, and children in the community who are stewards of land and market and family gardens.
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    Virginia On-Farm Soybean Test Plots, 2006
    Alexander, Wes; Balderson, T. Keith; Chappell, Glenn F.; Davis, Paul H.; Estienne, Cynthia Elizabeth; Johnson, Sam; Lewis, Matthew A.; Lawrence, Watson; Moore, David M.; Parrish, Michael J.; Slade, Glenn; Stafford, Carl; Wells, Kelvin; Lawrence, Chris; Holshouser, David L. (Virginia Cooperative Extension, 2006)
    Discusses data collected from soybean test plots in 2006 including variety selection, fungicides, maturity and development of plants, seed treatments, and tillage systems.