Showing papers by "North Carolina State University published in 2023"

Anisotropic superconductivity at KTaO ₃ (111) interfaces

Abstract: A two-dimensional, anisotropic superconductivity was recently found at the KTaO 3 (111) interfaces. The nature of the anisotropic superconducting transition remains a subject of debate. To investigate the origins of the observed behavior, we grew epitaxial KTaO 3 (111)-based heterostructures. We show that the superconductivity is robust against the in-plane magnetic field and violates the Pauli limit. We also show that the Cooper pairs are more resilient when the bias is along [11 2 ¯ ] (I ∥ [11 2 ¯ ]) and the magnetic field is along [1 1 ¯ 0] ( B ∥ [1 1 ¯ 0]). We discuss the anisotropic nature of superconductivity in the context of electronic structure, orbital character, and spin texture at the KTaO 3 (111) interfaces. The results point to future opportunities to enhance superconducting transition temperatures and critical fields in crystalline, two-dimensional superconductors with strong spin-orbit coupling.

Control of Phase Separation and Crystallization for <scp>High‐Efficiency</scp> and <scp>Mechanically Deformable</scp> Organic Solar Cells

Abstract: Stretchable organic solar cells (OSCs) have great potential as power sources for the next-generation wearable electronics. Although blending rigid photovoltaic components with soft insulating materials can easily endow the mechanical ductility of active layers, the photovoltaic efficiencies usually drops in the resulting OSCs. Herein, a high photovoltaic efficiency of 15.03% and a large crack-onset strain of 15.70% is simultaneously achieved based on a ternary blend consisting of polymer donor poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c']dithiophene-4,8-dione)] (PM6), non-fullerene accepter 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2′′,3′′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis (methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (Y6), and soft elastomer polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) through the control of phase separation and crystallization. By employing a high-boiling point solvent additive 1-chloronaphthalene (CN) with different solubilities for PM6 and Y6, the aggregation dynamics of PM6 and Y6 as well as the film solidification process are dramatically altered, allowing for the different molecular rearrangement and liquid–liquid phase separation evolution. Consequently, the ternary film with optimal CN content presents decreased SEBS domains and moderately improved molecular ordering of PM6 and Y6, enabling effective mechanical deformation and charge generation/transport. The revealed corrections between the film-formation process, film microstructure, and photovoltaic/mechanical characteristics in the ternary blend provide deep understanding of the morphology control toward high-performance stretchable OSCs.

Legacy and emerging per- and polyfluoroalkyl substances suppress the neutrophil respiratory burst

Abstract: Per- and polyfluoroalkyl substances (PFASs) are used in a multitude of processes and products, including nonstick coatings, food wrappers, and fire-fighting foams. These chemicals are environmentally-persistent, ubiquitous, and can be detected in the serum of 98% of Americans. Despite evidence that PFASs alter adaptive immunity, few studies have investigated their effects on innate immunity. The report here presents results of studies that investigated the impact of nine environmentally-relevant PFASs [e.g. perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid potassium salt (PFOS-K), perfluorononanoic acid (PFNA), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), 7H-perfluoro-4-methyl-3,6-dioxa-octane sulfonic acid (Nafion byproduct 2), and perfluoromethoxyacetic acid sodium salt (PFMOAA-Na)] on one component of the innate immune response, the neutrophil respiratory burst. The respiratory burst is a key innate immune process by which microbicidal reactive oxygen species (ROS) are rapidly induced by neutrophils in response to pathogens; defects in the respiratory burst can increase susceptibility to infection. The study here utilized larval zebrafish, a human neutrophil-like cell line, and primary human neutrophils to ascertain whether PFAS exposure inhibits ROS production in the respiratory burst. It was observed that exposure to PFHxA and GenX suppresses the respiratory burst in zebrafish larvae and a human neutrophil-like cell line. GenX also suppressed the respiratory burst in primary human neutrophils. This report is the first to demonstrate that these PFASs suppress neutrophil function and support the utility of employing zebrafish larvae and a human cell line as screening tools to identify chemicals that may suppress human immune function.

Generating a framework for gender and sexual diversity‐inclusive STEM education

Abstract: Students who identify as LGBTQ continue to report feelings of being unsafe at school because of their sexual orientation, gender identity, and gender expression. Access to a gender and sexual diversity (GSD)-inclusive curriculum and supportive teachers may positively improve the school climate for LGBTQ students, but these supports are often not included in STEM classrooms. One response is to ensure that STEM teachers are prepared to integrate GSD-inclusive STEM teaching into their classrooms. This review systematically analyzed the literature on supporting and affirming GSD in K-12 and higher education STEM education contexts. The 81 selected studies were qualitatively analyzed using inductive thematic analysis and epistemic network analysis, and the findings showed that GSD-inclusive STEM education literature coheres around six highly related constructs: Heteronormativity, Social Justice, Epistemic Knowledge of Science and Inquiry, Identity, Embodiment, and GSD language. Identifying these constructs, and the connections among them, led to the generation of an operational framework of GSD-inclusive STEM teaching that can inform and guide STEM teacher education programs and STEM teacher professional development to develop STEM educators' equity literacy around GSD to foster bias-free, equitable, inclusive STEM classrooms.

Idebenone attenuates ferroptosis by inhibiting excessive autophagy via the ROS-AMPK-mTOR pathway to preserve cardiac function after myocardial infarction

Abstract: Cardiovascular diseases (CVDs) are the leading causes of mortality worldwide. As a type of CVDs, myocardial infarction (MI) induces ischemia hypoxia, which leads to excessive reactive oxygen species (ROS), resulting in multiple cell deaths and contributing to the subsequent development of heart failure or premature death. Recent evidence indicates that ROS-induced lipid peroxidation promotes autophagy and ferroptosis, leading to the loss of healthy myocardium and resulting in the dysfunction of cardiac tissue. Theoretically, cardiac function would be preserved after MI by inhibiting autophagy and ferroptosis. As an analog of coenzyme Q10 (CoQ10) and a clinically approved drug, idebenone would be used to inhibit ferroptosis and preserve cardiac function due to its capacity to improve mitochondrial physiology with antioxidant and anti-inflammatory properties. Here, we confirmed that the addition of idebenone inhibited H2O2-induced and RSL3-induced ferroptosis. Furthermore, the ROS-AMPK-mTOR pathway axis was identified as the signaling pathway that idebenone stimulated to prevent excessive autophagy and consequent ferroptosis. In the MI animal model, idebenone demonstrated a cardioprotective role by regulating ROS-dependent autophagy and inhibiting ferroptosis, which paves the way for the future clinical translation of idebenone in MI management.

Leveraging Deep Reinforcement Learning for Metacognitive Interventions Across Intelligent Tutoring Systems

Abstract: This work compares two approaches to provide metacognitive interventions and their impact on preparing students for future learning across Intelligent Tutoring Systems (ITSs). In two consecutive semesters, we conducted two classroom experiments: Exp. 1 used a classic artificial intelligence approach to classify students into different metacognitive groups and provide static interventions based on their classified groups. In Exp. 2, we leveraged Deep Reinforcement Learning (DRL) to provide adaptive interventions that consider the dynamic changes in the student’s metacognitive levels. In both experiments, students received these interventions that taught how and when to use a backward-chaining (BC) strategy on a logic tutor that supports a default forward-chaining strategy. Six weeks later, we trained students on a probability tutor that only supports BC without interventions. Our results show that adaptive DRL-based interventions closed the metacognitive skills gap between students. In contrast, static classifier-based interventions only benefited a subset of students who knew how to use BC in advance. Additionally, our DRL agent prepared the experimental students for future learning by significantly surpassing their control peers on both ITSs.

Demand for older workers: What do we know? What do we need to learn?

Abstract: The employment rate for workers 55 and over has been increasing across the world for the last two decades. This creates opportunities for employers to diversify their workforce and retain valuable knowledge and skills, while at the same time posing the challenges of rising labor costs and blocked opportunities for younger workers. This study summarizes the economic tradeoffs facing organizations as they design their optimal age structure, along with recent research on how older workers fit into organizations. Empirical studies show that whereas wage and benefit costs increase with age, there is no conclusive evidence that productivity increases as well. Studies using macroeconomic data find no evidence that older workers block opportunities for younger workers, whereas recent papers using a more disaggregated approach find mixed results. A key challenge facing older workers is the decline over the last 20 years in the odds of becoming a new hire. Although the turnover rate for older workers is much lower than for other age groups, employers have concerns about accommodating their work environment and work schedule preferences. Resume studies show age discrimination also plays a factor, especially for women. The paper concludes with suggestions for future research, including interindustry and international comparisons of microeconomic data on employment by age group and re-examining matched employee-employer data sets.

Molecular Engineering of Cyclic Azobenzene‐Peptide Hybrid Ligands for the Purification of Human Blood Factor VIII via Photo‐Affinity Chromatography

Abstract: The use of benign stimuli to control the binding and release of labile biologics for their isolation from complex feedstocks is a key goal of modern biopharmaceutical technology. This study introduces cyclic azobenzene-peptide (CAP) ligands for the rapid and discrete photo-responsive capture and release of blood coagulation factor VIII (FVIII). A predictive method—based on amino acid sequence and molecular architecture of CAPs—is developed to correlate the conformation of cis/trans-CAP photo-isomers to FVIII binding and release. Combined in silico - in vitro analysis of FVIII:peptide interactions guide the design of a rational approach to optimize isomerization kinetics and biorecognition of CAPs. A photoaffinity adsorbent, prepared by conjugating selected CAP G-cycloAZOB[Lys-YYKHLYN-Lys]-G on translucent chromatographic beads, features high binding capacity (>6 mg of FVIII per mL of resin) and rapid photo-isomerization kinetics (τ < 30 s) when exposed to 420–450 nm light at the intensity of 0.1 W cm−2. The adsorbent purifies FVIII from a recombinant harvest using a single mobile phase, affording high product yield (>90%), purity (>95%), and blood clotting activity. The CAPs introduced in this report demonstrate a novel route integrating gentle operational conditions in a rapid and efficient bioprocess for the purification of life-saving biotherapeutics.

Comparison of a blind and an ultrasound‐guided technique for Retrobulbar anesthesia in dogs undergoing unilateral subconjunctival enucleation

Abstract: This study compared the quality of retrobulbar anesthesia using a blind inferior-temporal palpebral approach (ITP) with an ultrasound-guided supratemporal (ST) technique in dogs undergoing unilateral enucleation.Twenty-one client-owned dogs were undergoing enucleation.Dogs were randomly assigned to receive ITP (n = 10) or ST (n = 11) with 0.5% ropivacaine at 0.1 mL/cm of neurocranial length. The anesthetist was blinded to the technique. Intraoperative data included cardiopulmonary variables, inhalant anesthetics requirement, and requirement for rescue analgesia (intravenous fentanyl 2.5 mcg/kg). Postoperative data included pain scores, sedation scores, and need for intravenous hydromorphone (0.05 mg/kg). Treatments were compared using Wilcoxon's rank sum test or Fisher's exact test as appropriate. Comparison of variables over time were tested using a mixed effect linear model on rank. Significance was set at p = 0.05.Intraoperative cardiopulmonary variables and inhalant requirements were not different between groups. Dogs receiving ITP required median (interquartile range, IQR) 1.25 (0, 2.5) mcg/kg intraoperative fentanyl while those receiving ST required none (p < 0.01). Intraoperative fentanyl was required in 5/10 and 0/11 of dogs in the ITP and ST groups, respectively (p = 0.01). Postoperative analgesia requirements were not significantly different between groups; 2/10 and 1/10 dogs in the ITP and ST groups, respectively. Sedation score negatively affected pain score (p < 0.01).The ultrasound-guided ST technique was more effective at decreasing intraoperative opioid requirements than the blind ITP approach in dogs undergoing unilateral enucleation.

Elastic integrative analysis of randomised trial and real-world data for treatment heterogeneity estimation

Abstract: Abstract We propose a test-based elastic integrative analysis of the randomised trial and real-world data to estimate treatment effect heterogeneity with a vector of known effect modifiers. When the real-world data are not subject to bias, our approach combines the trial and real-world data for efficient estimation. Utilising the trial design, we construct a test to decide whether or not to use real-world data. We characterise the asymptotic distribution of the test-based estimator under local alternatives. We provide a data-adaptive procedure to select the test threshold that promises the smallest mean square error and an elastic confidence interval with a good finite-sample coverage property.

Differential bumble bee gene expression associated with pathogen infection and pollen diet

Abstract: Diet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology.Among infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade.Taken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.

Cystathionine gamma-lyase (Cth) induces efferocytosis in macrophages via ERK1/2 to modulate intestinal barrier repair

Abstract: Abstract Background The inflammatory response induced by intestinal ischaemia‒reperfusion injury (I/R) is closely associated with infectious complications and mortality in critically ill patients, and the timely and effective clearance of apoptotic cells is an important part of reducing the inflammatory response. Studies have shown that the efferocytosis by phagocytes plays an important role. Recently, studies using small intestine organoid models showed that macrophage efferocytosis could promote the repair capacity of the intestinal epithelium. However, no studies have reported efferocytosis in the repair of I/R in animal models. Results We used an in vivo efferocytosis assay and discovered that macrophage efferocytosis played an indispensable role in repairing and maintaining intestinal barrier function after I/R. In addition, the specific molecular mechanism that induced macrophage efferocytosis was Cth-ERK1/2 dependent. We found that Cth drove macrophage efferocytosis in vivo and in vitro. Overexpression/silencing Cth promoted/inhibited the ERK1/2 pathway, respectively, which in turn affected efferocytosis and mediated intestinal barrier recovery. In addition, we found that the levels of Cth and macrophage efferocytosis were positively correlated with the recovery of intestinal function in clinical patients. Conclusion Cth can activate the ERK1/2 signalling pathway, induce macrophage efferocytosis, and thus promote intestinal barrier repair.

Understanding the effect of cover crop use on prevented planting losses

Abstract: Cover cropping has the potential to improve resilience of agriculture to climate-change-induced extreme weather events. However, rigorous quantitative evidence on the resilience effect of cover crops is still lacking. Using a novel data set that combines satellite-based cover crop information and county-level crop insurance data, we examine the impact of planting cover crops on prevented-planting-related losses that are typically caused by heavy rainfall events. The US federal crop insurance program offers “prevented planting” coverage, which pays indemnities if insured growers are unable to plant their crop due to adverse weather. Linear fixed effects models, instrument-based estimation methods, long-difference models, and a number of other robustness checks are utilized in the empirical analysis to achieve the study objective. Our findings suggest that counties with higher cover crop adoption rates tend to have lower levels of crop insurance losses due to prevented planting. The resulting reduction in prevented planting risk also becomes larger with longer term, multiyear cover crop use. These results support the notion that cover crops improve soil conditions such that the likelihood and magnitude of prevented planting losses decrease. We posit that the ability of cover crops to handle excess moisture (i.e., through better water absorption and improved water infiltration in the soil) is the main factor in its ability to reduce prevented planting losses in the US Midwest.

Thermal resistance network model for thermal conductivity of normal liquid helium-4 and helium-3

Abstract: Abstract Liquid heliums are intriguing substances. Superfluid states below certain critical temperatures, notably liquid helium-4 and helium-3 exhibit ultra-high thermal conductivity in the superfluid phase. However, the microscopic origin of the thermal conductivity of liquid heliums in the normal phase remains unclear. In this work, we employ the thermal resistance network model to calculate the thermal conductivities of normal liquid helium-4 (He I) and helium-3. Predicted values are not only in good agreement with the measurements but also reproduce the experimental trend of thermal conductivity increasing with temperature and pressure.

The Human Gut Microbiome

Abstract: We evolved in a bacterial world. The gut microbiome affects our development, our behaviors and moods, our immune system and overall health, and our ability to break down toxins and harvest energy from the foods that we eat. Microbes affect our health, behavior, and other aspects of our lives and well-being. Decisions we make in our daily lives, from what foods we eat, to how much time we spend outdoors can help us make the most of our gut microbiome, and all the good that it can do for us.

Patterns and drivers of nutrient trends in flood-impacted surface waters: Insights from Bayesian modeling approaches

Abstract: Extreme events, including regional floods caused by hurricanes, have the potential to mobilize and transport nutrients across the landscape, creating public and environmental health concerns. Several studies have characterized the contaminants in floodwaters, but few studies offer insights into which watershed characteristics explain flood water quality signatures. To address lack of understanding on flood water quality descriptors, we aimed to explain floodwater nutrient concentrations as a function of different environmental variables. Specifically, we quantified nitrogen and phosphorus concentrations in floodwaters across the Atlantic Coastal Plain of North Carolina (USA) after Hurricane Florence, a major tropical storm that delivered up to 700 mm of rainfall to the region during September 2018. We also constructed a multivariate, spatial Bayesian model to explain nutrient responses as a function of different hydroclimatic factors, land use classifications, and nearby pollution point sources. Nutrient samples were collected at 51 different sites at four different time points spanning a year after Hurricane Florence impact: during major flood conditions and after floodwaters had receded. Samples were assessed for total Kjeldahl nitrogen, total ammonia nitrogen, nitrate and nitrites, total phosphorus, and orthophosphate. Results from this analysis show that nutrient concentrations were very low in floodwaters, with the exception of several sites that exhibited excessively high total Kjeldahl nitrogen, total phosphorus, and orthophosphate concentrations. Furthermore, modeling results indicate that swine production facilities (concentrated animal feeding operations; CAFOs), wastewater treatment plant (WWTP) proximity, and precipitation variables were important in explaining nutrient concentrations in floodwaters. This research suggests that swine CAFOs and WWTPs were likely sources of nutrient exports associated with Hurricane Florence, with rainfall amount being a primary driver.&#160;

Bayesian hierarchical modeling characterizes spatio-temporal variability in phosphorus export across the contiguous United States

Abstract: Phosphorus (P) inputs from anthropogenic activities are subject to riverine (hydrologic) P export, causing water quality problems in lakes and coastal systems. Nutrient budgets have been used as a quantitative means of assessing the amount of nutrients imported to and exported from a system.&#160;However, at large spatial scales, estimates of hydrologic P losses are usually not available or assumed as a fixed fraction of the budget terms. In addition, fluxes in nutrient budgets are generally not quantified at regular intervals. In this study, we estimate P losses across 150 US watersheds at an approximately 4-digit Hydrologic Unit Code (HUC 4) watershed scale from 1997-2017. To explain the spatio-temporal variability in these estimates, we develop a Bayesian model based on various anthropogenic P inputs (e.g., fertilizer, animal manure, point sources, and atmospheric deposition) and outputs (crop removal) from national inventories, climatic factors, background soil P content, and watershed characteristics. In addition, a hierarchical approach accounts for additional sources of variability across different regions. Model results help us identify hot spots of P loss, along with the primary factors contributing to these losses. Results indicate that the greatest P losses (per unit area) occur in the Mid-Atlantic and Great Lakes regions, mainly due to high anthropogenic inputs. Additionally, the Upper Colorado region is found to have the highest temporal variability in P loss, whereas the Lower Mississippi region has the lowest.

Posthuman Subjectivity in BCI-VR Entanglement

Abstract: This chapter argues that the entanglement of the human and technology produces a posthuman subjectivity—a form of subjectivity that underscores the mutual shaping and perpetually shifting boundaries of the human. Attending to posthuman subjectivity refuses the longstanding dualisms between humans and technology or natural and artificial. As a case study to demonstrate this understanding of posthuman subjectivity, this chapter draws on posthumanist works by Bruno Latour and Karen Barad to explore the intertwinement of the human, brain–computer interfaces (BCIs), and virtual reality (VR) as an example to suggest the permeability of boundaries and fluidity of subjectivity between the human and nonhuman other. By adopting a feminist posthumanist lens, I critique the existing model of subjectivity and propose to reframe the human–BCI-VR relationship as a posthuman subjectivity. The chapter has three objectives. First, I will provide an overview and discuss the history of BCIs. This will be followed by an introduction of VR and the promises that the integration of VR with BCIs hold by exploring therapy and gaming as two domains. Finally, I look at how the convergence of BCI and VR results in a new form of subjective experience and address the necessity of a posthuman understanding of subjectivity.