VTechWorks
VTechWorks provides global access to Virginia Tech scholarship, including journal articles, books, theses, dissertations, conference papers, slide presentations, technical reports, working papers, administrative documents, videos, images, and more by faculty, students, and staff. Faculty can deposit items to VTechWorks from Elements, including journal articles covered by the University open access policy. Email vtechworks@vt.edu for help.
Open Access Policy
Virginia Tech's open access policy enables researchers to deposit the accepted version of scholarly articles with no embargo.
Theses and Dissertations
Virginia Tech was first in the world to require ETDs in 1997, and continues to add scans of older theses and dissertations.
Open Textbooks
More than 50 freely available and openly licensed textbooks are among our most downloaded items.
Communities in VTechWorks
Select a community to browse its collections.
Recent Submissions
Functional Group Transposition Enabled by Palladium and Photo Dual Catalysis
Xu, Menghua; Wu, Chengjun; Chen, Ming (American Chemical Society, 2025-11-05)
The ability to precisely modify the structure of molecules is a captivating process that has fascinated the synthetic organic and medicinal chemistry communities. To this end, functional group transposition has recently emerged as a powerful strategy to edit molecules and allow for access to novel chemical entities without significantly altering the synthesis routes. Here we disclose an unusual functional group transposition reaction. By using palladium and photo dual catalysis, this radical-induced process enables the transposition between an iodo group and a boryl group to convert iodoarenes appended with an alkylboronate group to arylboronates appended with an alkyl iodide.
Enantioselective Syntheses of Secondary Alkylboronates via Asymmetric Regioselective Reduction of 1,3-Dienylboronates
Cao, Wen-Bin; Hu, Lingfei; Liu, Jiaming; Chen, George; Lu, Gang; Chen, Ming (WILEY-V C H VERLAG GMBH, 2026-01-16)
We report herein the development of catalytic asymmetric synthesis of secondary alkylboronates. Under the optimal conditions, Cu-catalyzed semi-reduction of 1-alkyl- or 1,3-dialkyl-substituted 1-boryl-1,3-butadienes forms secondary alkylboronates with excellent regioselectivities and enantioselectivities. With H2O as the source of hydrogen, the reaction proceeds through a protoboration and protodeboration cascade reaction sequence to generate the desired boronates. By using a slightly modified protocol, the process allows for access to enantioenriched deuterium-labeled secondary alkylboronates. Density functional theory (DFT) studies were conducted to probe the origins of selectivities.
Temperature impacts the environmental suitability for malaria transmission by Anopheles gambiae and Anopheles stephensi
Villena, Oswaldo C.; Ryan, Sadie J.; Murdock, Courtney C.; Johnson, Leah R. (Wiley, 2022-08)
Extrinsic environmental factors influence the spatiotemporal dynamics of many organisms, including insects that transmit the pathogens responsible for vector-borne diseases (VBDs). Temperature is an especially important constraint on the fitness of a wide variety of ectothermic insects. A mechanistic understanding of how temperature impacts traits of ectotherms, and thus the distribution of ectotherms and vector-borne infections, is key to predicting the consequences of climate change on transmission of VBDs like malaria. However, the response of transmission to temperature and other drivers is complex, as thermal traits of ectotherms are typically nonlinear, and they interact to determine transmission constraints. In this study, we assess and compare the effect of temperature on the transmission of two malaria parasites, Plasmodium falciparum and Plasmodium vivax, by two malaria vector species, Anopheles gambiae and Anopheles stephensi. We model the nonlinear responses of temperature dependent mosquito and parasite traits (mosquito development rate, bite rate, fecundity, proportion of eggs surviving to adulthood, vector competence, mortality rate, and parasite development rate) and incorporate these traits into a suitability metric based on a model for the basic reproductive number across temperatures. Our model predicts that the optimum temperature for transmission suitability is similar for the four mosquito–parasite combinations assessed in this study, but may differ at the thermal limits. More specifically, we found significant differences in the upper thermal limit between parasites spread by the same mosquito (A. stephensi) and between mosquitoes carrying P. falciparum. In contrast, at the lower thermal limit the significant differences were primarily between the mosquito species that both carried the same pathogen (e.g., A. stephensi and A. gambiae both with P. falciparum). Using prevalence data, we show that the transmission suitability metric (Formula presented.) calculated from our mechanistic model is consistent with observed P. falciparum prevalence in Africa and Asia but is equivocal for P. vivax prevalence in Asia, and inconsistent with P. vivax prevalence in Africa. We mapped risk to illustrate the number of months various areas in Africa and Asia predicted to be suitable for malaria transmission based on this suitability metric. This mapping provides spatially explicit predictions for suitability and transmission risk.
Humidity - The overlooked variable in the thermal biology of mosquito-borne disease
Brown, Joel J.; Pascual, Mercedes; Wimberly, Michael C.; Johnson, Leah R.; Murdock, Courtney C. (Wiley, 2023-07)
Vector-borne diseases cause significant financial and human loss, with billions of dollars spent on control. Arthropod vectors experience a complex suite of environmental factors that affect fitness, population growth and species interactions across multiple spatial and temporal scales. Temperature and water availability are two of the most important abiotic variables influencing their distributions and abundances. While extensive research on temperature exists, the influence of humidity on vector and pathogen parameters affecting disease dynamics are less understood. Humidity is often underemphasized, and when considered, is often treated as independent of temperature even though desiccation likely contributes to declines in trait performance at warmer temperatures. This Perspectives explores how humidity shapes the thermal performance of mosquito-borne pathogen transmission. We summarize what is known about its effects and propose a conceptual model for how temperature and humidity interact to shape the range of temperatures across which mosquitoes persist and achieve high transmission potential. We discuss how failing to account for these interactions hinders efforts to forecast transmission dynamics and respond to epidemics of mosquito-borne infections. We outline future research areas that will ground the effects of humidity on the thermal biology of pathogen transmission in a theoretical and empirical framework to improve spatial and temporal prediction of vector-borne pathogen transmission.
Skin bacterial community differences among three species of co-occurring Ranid frogs
Gajewski, Zachary; Johnson, Leah R.; Medina, Daniel; Crainer, William W.; Nagy, Christopher M.; Belden, Lisa K. (PeerJ, 2023-07-14)
Skin microbial communities are an essential part of host health and can play a role in mitigating disease. Host and environmental factors can shape and alter these microbial communities and, therefore, we need to understand to what extent these factors influence microbial communities and how this can impact disease dynamics. Microbial communities have been studied in amphibian systems due to skin microbial communities providing some resistance to the amphibian chytrid fungus, Batrachochytrium dendrobatidis. However, we are only starting to understand how host and environmental factors shape these communities for amphibians. In this study, we examined whether amphibian skin bacterial communities differ among host species, host infection status, host developmental stage, and host habitat. We collected skin swabs from tadpoles and adults of three Ranid frog species (Lithobates spp.) at the Mianus River Gorge Preserve in Bedford, New York, USA, and used 16S rRNA gene amplicon sequencing to determine bacterial community composition. Our analysis suggests amphibian skin bacterial communities change across host developmental stages, as has been documented previously. Additionally, we found that skin bacterial communities differed among Ranid species, with skin communities on the host species captured in streams or bogs differing from the communities of the species captured on land. Thus, habitat use of different species may drive differences in host-associated microbial communities for closely-related host species.