Pennsylvania State University
  • University Park, PA, United States
Recent publications
The revolutionary role of tissue adhesives in wound closure, tissue sealing, and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing. In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators (exemplified by sodium periodate and silver nitrate), herein, the natural polyphenolic compound tannic acid (TA) was used to achieve near instantaneous (<25s), hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant, anti-inflammatory, and antimicrobial activities (3A-TCMBAs). The resulting materials were self-healing and possessed low swelling ratios (<60%) as well as considerable mechanical strength (up to ∼1.0 MPa), elasticity (elongation ∼2700%), and adhesion (up to 40 kPa). The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability, favorable cytocompatibility and cell migration, as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli (>90% bacterial death upon near-infrared (NIR) irradiation). In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs + NIR treatment could promote wound closure and collagen deposition and improve the collagen I/III ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines. Further, phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation & remodeling of the extracellular matrix (ECM) in the late stage (supported by phased CD31 (platelet endothelial cell adhesion molecule-1) PDGF (platelet-derived growth factor) and VEGF (vascular endothelial growth factor) expression as well as elevated matrix metalloprotein-9 (MMP-9) expression on day 21), resulting in scarless wound healing. The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant, new class of bioadhesive.
My research focuses on elucidating the chemical communication systems linking plants, herbivores, and natural enemies. My interests in integrating chemistry and agriculture led to my graduate studies in the emerging field of chemical ecology. My thesis research resulted in the identification, synthesis, and application of boll weevil sex pheromones. My research group subsequently developed chemical lures for more than 20 species of pest insects. I then shifted my focus to some of the first studies of the chemical signals produced by plants being attacked by herbivores. When insects feed, elicitors in the insects’ oral secretions, such as volicitin, a fatty acid–amino acid conjugate elicitor, stimulate plants to release volatile organic compounds. Parasitoid wasps learn to associate these species-specific volatiles with their herbivore hosts. These volatiles also prime nearby plants to activate a faster and higher defense response upon attack. Throughout my career, I have collaborated with scientists from diverse disciplines to tackle fundamental questions in chemical ecology and create innovative solutions for insect management. Our collaborative research has fundamentally changed and improved our understanding of the ongoing coevolution of plants, their herbivores, and the natural enemies that attack those herbivores. Expected final online publication date for the Annual Review of Entomology, Volume 68 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
The high demand for rapid wound healing has spurred the development of multifunctional and smart bioadhesives with strong bioadhesion, antibacterial effect, real-time sensing, wireless communication, and on-demand treatment capabilities. Bioadhesives with bio-inspired structures and chemicals have shown unprecedented adhesion strengths, as well as tunable optical, electrical, and bio-dissolvable properties. Accelerated wound healing has been achieved via directly released antibacterial and growth factors, material or drug-induced host immune responses, and delivery of curative cells. Most recently, the integration of biosensing and treatment modules with wireless units in a closed-loop system yielded smart bioadhesives, allowing real-time sensing of the physiological conditions (e.g., pH, temperature, uric acid, glucose, and cytokine) with iterative feedback for drastically enhanced, stage-specific wound healing by triggering drug delivery and treatment to avoid infection or prolonged inflammation. Despite rapid advances in the burgeoning field, challenges still exist in the design and fabrication of integrated systems, particularly for chronic wounds, presenting significant opportunities for the future development of next-generation smart materials and systems.
Agroecosystem management practices, plant-microbe interactions, and climate are all factors that influence soil microbial community diversity and functionality. Herein, we assessed diversity of soil bacterial-archaeal assemblages and denitrification gene markers in a long-term tillage field experiment. We evaluated bulk and rhizosphere soils from two crop years (corn and soybean) of a three-year rotation of corn-soybean-small grain + cover crop. Soil samples were collected at three growth stages from corn and soybean plants and across three tillage practices that had been applied every year for 40 years. Tillage practices represented three levels of disturbance intensity ranging from low (no-till) to intermediate (chisel-disk) to high (moldboard plow) intensities. Bacterial assemblage diversity differed in soils having contrasting tillage histories and from bulk or rhizosphere soil (compartments), crop year, and growth stage. Compared to plowed and chisel-disked soils, no-till soils had lower abundances of denitrification genes, higher abundances of genes for dissimilatory nitrate reduction to ammonium (DNRA), and higher abundances of family-level taxa associated with archaeal nitrification and anammox. Soybean rhizospheres exerted stronger selection on bacterial-archaeal composition and diversity relative to corn rhizospheres. Abundances of N genes were grouped by factors related to weather, as well as management and soil compartment, which could impact activity related to denitrification and DNRA. Low intensity tillage may provide an option to reduce potential ‘hot spots’ or ‘hot moments’ for N losses in agricultural soils, although weather and crop type are also important factors that can influence how tillage affects microbial assemblages and microbial N use.
The uncoupling of animal and crop production has resulted in long-term accumulation of manure nutrients in many areas, contributing to nutrient pollution. Prudent recycling of manure's nutrient resources requires reconnecting operations that produce manure with agricultural lands in need of nutrients. Thus the need to frame manure management via “manuresheds": the land (i.e. cropland, rangeland) surrounding livestock production operations where nutrients can be recycled on agricultural lands while balancing goals for production, environmental quality, and quality of life. We explore manureshed management as an evolution of national, regional, and local trends in nutrient sources and sinks. Results of our temporal assessments highlight not only system inertia, but the dynamic nature of nutrient flows and the potential for manureshed management to reverse nutrient imbalances at various scales. As a tool for a circular economy, manureshed management requires coordination beyond the farmgate, engaging specialists, industries, and other stakeholders.
Insects have application in poultry feed because of their capacity to sustainably repurpose wastes into nutrient-dense feeds, combined with the demand for poultry meat and eggs in the diets of the growing human population. Additionally, poultry naturally consumes insects, thus insects may enhance poultry welfare. Several insects are commercially reared including the house cricket (Acheta domesticus L.), yellow mealworm (Tenebrio molitor L.), and black soldier fly larvae (Hermetia illucens L.). Insect nutrient concentrations are affected by species, stage of development, feedstock on which they are raised, and processing method. Insects are a concentrated source of energy and protein with an excellent balance of essential amino acids, of which methionine levels are higher than standard corn and soybean meal sources commonly utilized in poultry diets. Because they are readily eaten and well utilized by poultry, insects are an effective source of nutrition in poultry feed for a burgeoning world population.
Background: Pharmaceutical drug therapy problems (DTPs) are a major public health problem. We examined patient-level risk factors for DTPs among Cambodian Americans. Methods: Community health workers (CHWs) verbally administered surveys and completed a detailed medication review form with participants. A doctoral-level pharmacist reviewed the form with the patient and CHW to determine DTP number and type (appropriateness, effectiveness, safety, and adherence). Results: Participants (n = 63) averaged 55 years old, 6 years of education, 52% were married, 87% spoke Khmer at home, with modal household income <$20,000 (41%). The percentage of participants with DTPs was: 45% appropriateness, 25% effectiveness, 64% safety, and 30% adherence, averaging 3.7 DTPs per patient. In multiple regressions, patient characteristics uniquely predicted each type of DTP. In a multiple regression controlling for number of medications, being married reduced total DTPs (IRR = 0.70) and being depressed increased total DTPs (IRR = 1.26). Conclusions: Vulnerable patients should be prioritized for pharmacist/CHW teams to identify DTPs.Trial registration: ClinicalTrials.gov identifier: NCT02502929.
Alternative splicing (AS) contributes to diversifying and regulating cellular responses to environmental conditions and developmental cues by differentially producing multiple mRNA and protein isoforms from a single gene. Previous studies on AS in pathogenic fungi focused on profiling AS isoforms under a limited number of conditions. We analysed AS profiles in the rice blast fungus Magnaporthe oryzae, a global threat to rice production, using high-quality transcriptome data representing its vegetative growth (mycelia) and multiple host infection stages. We identified 4,270 AS isoforms derived from 2,413 genes, including 499 genes presumably regulated by infection-specific AS. AS appears to increase during infection, with 32.7% of the AS isoforms being produced during infection but absent in mycelia. Analysis of the isoforms observed at each infection stage showed that 636 AS isoforms were more abundant than corresponding annotated mRNAs, especially after initial hyphal penetration into host cell. Many such dominant isoforms were predicted to encode regulatory proteins such as transcription factors and phospho-transferases. We also identified the genes encoding distinct proteins via AS and confirmed the translation of some isoforms via a proteomic analysis, suggesting potential AS-mediated neo-functionalization of some genes during infection. Comprehensive profiling of the pattern of genome-wide AS during multiple stages of rice-M. oryzae interaction established a foundational resource that will help investigate the role and regulation of AS during rice infection.
A new species of Heligmosomoides Hall, 1916 is proposed for nematodes collected from deer mice, Peromyscus maniculatus, in western Canada. The unequivocal diagnostic character for this species is the presence of two internal bursal membranes. Only four species, Heligmosomoides bullosus, Heligmosomoides douglasi, Heligmosomoides montanus and Heligmosomoides vandegrifti, are characterized as possessing a single internal bursal membrane. The genetic distance between Heligmosomoides bibullosus sp. nov., and its putative sister clade Heligmosomoides vandegrifti is congruent with their geographic separation by the mountain range of the Rockies and 4000 km; both morphological difference as well as geography and genetic distance suggest isolation among the two species. Further, H. bibullosus sp. nov. infects deer mice (P. maniculatus) whereas H. vandegrifti is frequently collected in white-footed mice (P. leucopus). Finally, this study supports the taxonomic importance of the monodelphic/didelphic condition as a diagnostic trait within the family, the paraphyly of Heligmosomoides, and reveals undocumented diversity of Heligmosomoides in Nearctic rodents of the Neotominae. The present taxon is the third species in members of this subfamily of rodents.
How the gut microbiota is organized across space is postulated to influence microbial succession and its mutualistic relationships with the host. The lack of dynamic or perturbed abundance data poses considerable challenges for characterizing the spatial pattern of microbial interactions. We integrate allometric scaling theory, evolutionary game theory, and prey-predator theory into a unified framework under which quasi-dynamic microbial networks can be inferred from static abundance data. We illustrate that such networks can capture the full properties of microbial interactions, including causality, the sign of the causality, strength, and feedback loop, and are dynamically adaptive along spatial gradients, and context-specific, characterizing variability between individuals and within the same individual across time and space. We design and conduct a gut microbiota study to validate the model, characterizing key spatial determinants of the microbial differences between ulcerative colitis and healthy controls. Our model provides a sophisticated means of unraveling a complete atlas of how microbial interactions vary across space and quantifying causal relationships between such spatial variability and change in health state.
The second year of the COVID-19 pandemic in the Arctic was dominated by the Delta wave that primarily lasted between July and December 2021 with varied epidemiological outcomes. An analysis of the Arctic’s subnational COVID-19 data revealed a massive increase in cases and deaths across all its jurisdictions but at varying time periods. However, the case fatality ratio (CFR) in most Arctic regions did not rise dramatically and was below national levels (except in Northern Russia). Based on the spatiotemporal patterns of the Delta outbreak, we identified four types of pandemic waves across Arctic regions: Tsunami (Greenland, Iceland, Faroe Islands, Northern Norway, Northern Finland, and Northern Canada), Superstorm (Alaska), Tidal wave (Northern Russia), and Protracted Wave (Northern Sweden). These regionally varied COVID-19 epidemiological dynamics are likely attributable to the inconsistency in implementing public health prevention measures, geographical isolation, and varying vaccination rates. A lesson remote and Indigenous communities can learn from the Arctic is that the three-prong (delay-prepare-respond) approach could be a tool in curtailing the impact of COVID-19 or future pandemics. This article is motivated by previous research that examined the first and second waves of the pandemic in the Arctic. Data are available at https://arctic.uni.edu/arctic-covid-19.
Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a migratory moth that annually migrates northward each spring from sites in southern Florida and southern Texas. This caterpillar pest feeds on and damages row, turf and vegetable crops in the eastern and central U.S. Before migrating in spring, it feeds on cover crops in central and eastern Florida and expands its populations. Our objective was to use multi-year studies to compare fall armyworm populations that develop in cover crop plants. A series of field experiments and a laboratory feeding study were conducted to compare infestation and feeding and of fall armyworm on different cover crop plants. Field experiments had plots planted with corn (Zea mays L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench], a standard cover crop in Florida, and two alternative cover crops, sunn hemp (Crotalaria juncea L.) and cowpea [Vigna unguiculata (L.) Walpers spp. unguiculata]. Another trial compared populations in sorghum-sudangrass and in mixtures of sorghum-sudangrass with buckwheat (Fagopyrum esculentum Moench) or pearl millet (Cenchrus americanus (L.) Morrone). Fall armyworm larvae were fed and allowed to develop on different sunn hemp germplasm in a laboratory trial. Field populations of fall armyworm were highest on corn, followed by sorghum-sudangrass. Sunn hemp and cowpea had larval populations 70–96% less than on sorghum-sudangrass, suggesting replacement of this cover crop with either plant species might help reduce areawide populations of resident or migratory fall armyworm. Larvae collected from cover crop plots had parasitism levels that averaged 30%, with Chelonus insularis (Hymenoptera: Braconidae) emerging as the most commonly-collected species. Larval feeding on different sunn hemp germplasm lines resulted in no difference in weight gain. Replacing sorghum-sudangrass with sunn hemp varieties or germplasm should be acceptable as a replacement cover crop for areawide management of fall armyworm.
Magnetic semimetals are very promising for potential applications in novel spintronic devices. Nevertheless, realizing tunable topological states with magnetism in a controllable way is challenging. Here, we report novel magnetic states and the tunability of topological semimetallic states through the control of Eu spin reorientation in Eu1−xSrxMn1−zSb2. Increasing the Sr concentration in this system induces a surprising reorientation of noncollinear Eu spins to the Mn moment direction and topological semimetallic behavior. The Eu spin reorientations to distinct collinear antiferromagnetic orders are also driven by the temperature/magnetic field and are coupled to the transport properties of the relativistic fermions generated by the 2D Sb layers. These results suggest that nonmagnetic element doping at the rare earth element site may be an effective strategy for generating topological electronic states and new magnetic states in layered compounds involving spatially separated rare earth and transition metal layers.
Objective The CMS mandated hospital price transparency reporting on January 1, 2021 aiming to empower patients, enhance market competition, and curtail healthcare costs in the US. We aimed to characterize variability in hospital pricing reported by 1982 hospitals on six standard procedures (including abdominal ultrasound, diagnostic colonoscopy, kidney function blood test panel, knee arthroscopic cartilage removal, magnetic resonance imaging scan of brain, and pelvis computed tomography scan with contrast), with a particular focus on variations in pricing by insurance plan type. Results We found substantial heterogeneity across insurance plan types. The minimum number of prices reported was 18,679 for knee arthroscopic cartilage removal (reported by 908 hospitals, average = 21 prices/hospital), while the maximum number of prices reported was 44,921 for abdominal ultrasound (reported by 1861 hospitals, average = 24 prices/hospital). In general, reported hospital pricing was highest for the list price, followed by cash price and prices negotiated with commercial insurance plans. Government insurance, including Medicare, Medicaid and Veterans/Tricare plans, had much lower prices. However, prices were very heterogeneous with substantial overlaps between pricing for all plan types. The coefficients of variation for all procedures exceeded 100%, ranging from 106% for knee arthroscopic cartilage removal to 397% for kidney function blood test panel.
Individual atomic defects in 2D materials impact their macroscopic functionality. Correlating the interplay is challenging, however, intelligent hyperspectral scanning tunneling spectroscopy (STS) mapping provides a feasible solution to this technically difficult and time consuming problem. Here, dense spectroscopic volume is collected autonomously via Gaussian process regression, where convolutional neural networks are used in tandem for spectral identification. Acquired data enable defect segmentation, and a workflow is provided for machine-driven decision making during experimentation with capability for user customization. We provide a means towards autonomous experimentation for the benefit of both enhanced reproducibility and user-accessibility. Hyperspectral investigations on WS 2 sulfur vacancy sites are explored, which is combined with local density of states confirmation on the Au{111} herringbone reconstruction. Chalcogen vacancies, pristine WS 2 , Au face-centered cubic, and Au hexagonal close-packed regions are examined and detected by machine learning methods to demonstrate the potential of artificial intelligence for hyperspectral STS mapping.
Background: The COVID-19 pandemic has been accompanied by increases in cannabis consumption, which might relate to dispensary marketing activities. As part of an ongoing project monitoring cannabis dispensary websites in Northern California and Reno, Nevada, we noticed many websites added announcements and "pop-up" communications in response to lockdowns. This brief report describes the cannabis dispensary website communications related to COVID-19 with the aim to provide insight into emerging marketing messages that may increase cannabis consumption in times of crisis. Methods: Content analysis of COVID-19 announcements present on cannabis dispensary websites in San Francisco/Alameda Counties (n = 32), and the Reno area (n = 15) in April-May 2020 shortly after lockdowns were implemented. Results: COVID-19 announcements were present on 25/32 (78%) of dispensary websites in San Francisco/Alameda and 9/15 (60%) of websites in the Reno area. Almost all COVID-19 announcements (88% San Francisco/Alameda, 89% Reno) announced operational changes such as delivery or curbside pickup services, 72% and 56% respectively announced patron/employee safety measures. Health related messages were present; about half of website announcements referred to government/health authorities, 44% of Reno area announcements used healthcare rhetoric, and some San Francisco/Alameda announcements included suggestions for using cannabis to mitigate infection risk or manage anxiety. Conclusions: Most cannabis dispensaries in the study region implemented COVID-19 pandemic operational changes to maintain product availability, and many positioned their identity with health - either by referring to health authorities, or using health rhetoric, and a minority gave health advice. Cannabis dispensary websites provide a timely snapshot of marketing practices that may contribute to increases in cannabis use during stressful events.
Although social–emotional learning (SEL) and ethics education are important, it remains a challenging issue to effectively implement these practices. In this study, a Philosophical Ethics in Early Childhood approach is proposed for developing children's social–emotional competence and Theory of Mind. To evaluate the effectiveness of this expanded intervention, an experiment was conducted by assigning 73 children aged 3–5 to an experimental group ( N = 37) and a comparative group ( N = 36). Parents and teachers completed Head Start Competence Scales, the Theory of Mind Inventory and parent and teacher questionnaires. Teacher and Child Interviews were conducted. According to the teachers’ reports, the experimental group children demonstrated significantly increased social–emotional competence skills and increased understanding of their own and others’ emotions compared to the comparative group children. This program includes games, extension activities, and dialogue to support children in deeply thinking about social and emotional dilemmas, sharing their ideas, and creating solutions.
Unintentional overdose deaths, most involving opioids, have eclipsed all other causes of US deaths for individuals less than 50 years of age. An estimated 2.4 to 5 million individuals have opioid use disorder (OUD) yet a minority receive treatment in a given year. Medications for OUD (MOUD) are the gold standard treatment for OUD however early dropout remains a major challenge for improving clinical outcomes. A Cascade of Care (CoC) framework, first popularized as a public health accountability strategy to stem the spread of HIV, has been adapted specifically for OUD. The CoC framework has been promoted by the NIH and several states and jurisdictions for organizing quality improvement efforts through clinical, policy, and administrative levers to improve OUD treatment initiation and retention. This roadmap details CoC design domains based on available data and potential linkages as individual state agencies and health systems typically rely on limited datasets subject to diverse legal and regulatory requirements constraining options for evaluations. Both graphical decision trees and catalogued studies are provided to help guide efforts by state agencies and health systems to improve data collection and monitoring efforts under the OUD CoC framework.
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Bing Pan
  • Department of Recreation, Park, and Tourism Management
Gordon N. Fleming
  • Department of Physics
Michelle Gayle Newman
  • Department of Psychology
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