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 40 freely available and openly licensed textbooks are among our most downloaded items.
Communities in VTechWorks
Select a community to browse its collections.
Recent Submissions
Shifts in water use in grapevine due to an invasive sap-feeding planthopper persist following insect removal
Harner, Andrew D.; Leach, Heather; Briggs, Lauren; Smith, Donald E.; Zweifel, Roman; Centinari, Michela (Elsevier, 2025-02-01)
Increasing outbreaks of invasive insect pests pose a substantial threat to the functioning and viability of cultivated and wild woody perennial species worldwide. In the eastern U.S., the spotted lanternfly (Lycorma delicatula White; SLF), an invasive phloem-feeding planthopper, was reported to be able to negatively impact late-season plant carbon dynamics in various woody perennial species following repeated or prolonged infestation and feeding events. However, it remains unclear if SLF infestations also impact plant water relations and if SLF-mediated effects persist when populations are controlled and feeding stops. This study investigated how late-season exposure to SLF impacts whole-plant water relations by assessing diurnal sap flow and trunk radius changes in grapevines subjected to varying infestation densities of adult SLF. In two seasons, vines exposed to high infestation densities (an average of 180 SLFs per vine) for up to 31–32 days of cumulative SLF exposure had significantly lower sap flow rate than those with no SLF, resulting in up to 38 % less daily total water use. Trunk diurnal amplitudes increased under SLF infestation, but impacts were less dependent on infestation density, suggesting that grapevines may be utilizing trunk water storage during infestation to meet both grapevine water use and SLF sap ingestion. In both cases, SLF-mediated effects persisted following removal of SLFs, suggesting that exposure to high populations of SLF can alter patterns of late-season grapevine water use, at least when populations are not effectively controlled. These results indicate that SLF can modify both whole-plant water relations and carbon dynamics concurrently, further defining the implications that intensive infestations by high populations of SLF have for woody perennial whole-plant physiology.
Building an entrepreneurship education program in a technology-rich environment: Virginia Tech’s entrepreneurship ecosystem
Tseng, Chien-Chi; Townsend, David; Poff, Ron; Gnyawali, Devi (Edward Elgar Publishing, 2025-01-01)
In recent years, the entrepreneurship ecosystem at Virginia Tech has rapidly evolved into one of the leading global university entrepreneurship programs. Through an integrated mix of curricular and co-curricular programs and initiatives, Virginia Tech is leading the way in building a world-class entrepreneurship ecosystem throughout the Commonwealth of Virginia to serve the students, faculty and staff, Commonwealth citizens, and the entrepreneurship community at large. Building on the historic strengths as a pre-eminent STEM-focused institution, Virginia Tech’s comprehensive ecosystem encompasses a unique blend of academic courses and programs, student experiential learning, and a broader support system to advance technology commercialization and entrepreneurship efforts. Dedicated to entrepreneurship education excellence, Virginia Tech pushes the boundaries of knowledge acquisition and generation by taking a hands-on, transdisciplinary approach to prepare students to be leaders and problem-solvers. As the commonwealth’s most comprehensive university and a leading research institution, Virginia Tech’s entrepreneurship ecosystem spans multiple campuses across the Commonwealth and is anchored by our primary campus in Blacksburg, VA. These innovative and comprehensive efforts and demonstrated success have led to Virginia Tech’s winning the National Model Program Award for entrepreneurship education from the United States Association for Small Business and Entrepreneurship in 2022.
Recovery and Survival of Aerosolized Escherichia coli and Enterococcus faecium on Food-Grade Rubber, HDPE Plastic, Stainless Steel, and Waxed Cardboard
Le, Tuan; Eifert, Joseph D.; Etaka, Cyril A.; Strawn, Laura K. (WILEY, 2024-12)
Contamination of food contact surfaces by airborne transmission of pathogens from the environment has contributed to disease outbreaks. Therefore, this study evaluated the survival and recovery of aerosolized generic Escherichia coli and Enterococcus faecium from four food contact surfaces (food-grade silicone rubber, high-density polyethylene [HDPE] plastic, stainless steel, and waxed cardboard), after four contact times (10, 20, 40, and 60 min), two relative humidity (RH) levels (high: 80%–90%, low: 40%–50%), three distances from aerosolization source (0, 36.5, and 73 cm; E. coli only), and with and without airflow (E. coli only). ANOVA test with Tukey's HSD at α = 0.05 was used to determine how treatment combinations influenced recovery. At high humidity, E. coli recovery on all materials after 40 min was ~1.0 log lower than recovery after 10 min, and further reduced by 1.0 log at 60 min. At lower humidity, E. coli recovery on all materials was ~1.0 log lower at 10 and 20 min compared with high humidity. Distances exerted no significance, whereas airflow presence lowered E. coli recovery. E. coli survival on all materials declined from ~5.0 log CFU/coupon at 0 h to 3.5 log CFU/coupon at 6 h, and 2.0 log CFU/coupon at 24 h post-inoculation. E. coli recovery was significantly lower (p < 0.05) on waxed cardboard. Low RH and longer contact time reduced E. coli recovery but not E. faecium. E. faecium recovery was consistent across treatment combinations, with changes < 0.5 log CFU/coupon. The findings are relevant for the survival of bacteria on common food contact surfaces and the potential of transmission to food products.
Programmable quantum emitter formation in silicon
Jhuria, K.; Ivanov, V.; Polley, D.; Zhiyenbayev, Y.; Liu, W.; Persaud, A.; Redjem, W.; Qarony, W.; Parajuli, P.; Ji, Q.; Gonsalves, A. J.; Bokor, J.; Tan, L. Z.; Kante, B.; Schenkel, T. (NATURE PORTFOLIO, 2024-05-27)
Silicon-based quantum emitters are candidates for large-scale qubit integration due to their single-photon emission properties and potential for spin-photon interfaces with long spin coherence times. Here, we demonstrate local writing and erasing of selected light-emitting defects using femtosecond laser pulses in combination with hydrogen-based defect activation and passivation at a single center level. By choosing forming gas (N2/H2) during thermal annealing of carbon-implanted silicon, we can select the formation of a series of hydrogen and carbon-related quantum emitters, including T and Ci centers while passivating the more common G-centers. The Ci center is a telecom S-band emitter with promising optical and spin properties that consists of a single interstitial carbon atom in the silicon lattice. Density functional theory calculations show that the Ci center brightness is enhanced by several orders of magnitude in the presence of hydrogen. Fs-laser pulses locally affect the passivation or activation of quantum emitters with hydrogen for programmable formation of selected quantum emitters.
Juvenile hormone induces phosphorylation of insulin/insulin-like growth factor signaling proteins in previtellogenic Aedes aegypti mosquitoes
Zhao, Wenhao; Liu, Pengcheng; Saunders, Thomas R.; Zhu, Jinsong (WILEY, 2024-01-01)
Juvenile hormone (JH) plays a pivotal role in regulating post-emergence development and metabolism in previtellogenic female Aedes aegypti mosquitoes. In contrast, yolk protein precursor production and egg maturation after a blood meal are regulated by the steroid hormone 20-hydroxyecdysone, the insulin-like growth factor (IGF)/insulin signaling (IIS) pathway, and the mammalian target of rapamycin (mTOR) pathway. The role of IIS/mTOR signaling in female adults prior to blood feeding has not been thoroughly investigated. In this study, we identified a significant increase in the phosphorylation of key effector proteins in the IIS/mTOR signaling pathway, including eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), ribosomal protein S6 kinase (S6K) and forkhead box protein O1 (FoxO1), in previtellogenic females. In vitro fat body culture experiments suggest that JH induces these phosphorylations through rapid nongenomic signaling mediated by the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mTOR network. RNA interference experiments demonstrated that activation of IIS/mTOR signaling in previtellogenic females modulate metabolic gene expression, promoting the accumulation of energy reserves (glycogen and triglycerides), which influence mosquito fecundity. Additionally, depletion of either the insulin receptor (InR) or the JH receptor Methoprene-tolerant (Met) in adult mosquitoes abolished the phosphorylation of these proteins, indicating that both receptors are involved in JH-induced membrane-initiated signal transduction. Although the precise mechanisms remain unclear, this study uncovers a novel function of the IIS/mTOR pathway in adult mosquitoes before blood feeding, as well as a new mode of JH action through its crosstalk with the IIS pathway.