University of Arkansas

SiC MOSFETs offer significant benefits for power electronics applications due to their material properties, including increased switching speeds, reduced switching losses and improved power density. However, these benefits can also result in severe switching oscillation and electromagnetic interference (EMI) in SiC MOSFETs, which can cause device breakdown or damage. In this paper, an oscillation suppression method with clamping function and quantitative design is presented, which not only effectively clamps the drain-source voltage overshoot but also does not reduce the switching speed and increase the switching loss. Firstly, the clamping circuit based on a double-pulse circuit is proposed and its operating principle is described. Then, in order to achieve full suppression of oscillation below the clamping capacitor voltage, the high frequency equivalent circuit in the oscillation stage is derived and the snubber parameters are further quantitatively designed. Finally, an experimental platform is developed to verify the effectiveness of the proposed method. The experimental results show that the proposed method can effectively clamp the overshoot and suppress the switching oscillations, which will significantly improve the device application reliability.

Food contamination poses a significant threat to public health, the economy, and human health worldwide, occurring at any stage of the food supply chain, from farm to fork. Efficient and effective real‐time monitoring methods for the early identification and rapid detection of pathogen contamination are critical to preventing possible food safety issues. In the past decade, flexible electrochemical biosensors have rapidly expanded in the detection of foodborne pathogens, owing to their ability to function well at biological interfaces that may be soft, intrinsically curvy, irregular, or deformable. The most important features of flexible sensors are their flexibility, multifunctionality, low cost, and good compatibility with solution processing methods. These properties enable flexible sensors to be used in various applications, including smart packaging. This review focuses on the materials, structures, and fabrication methods of flexible biosensors, as well as their applications in food safety monitoring. It examines recent advances in electrochemical immunosensors and aptasensors for pathogen detection, with a focus on their key components and their application in food analysis, while critically examining their current trends, particularly in conjunction with nanomaterials such as carbon nanotubes, graphene, gold nanoparticles, Indium tin oxide, etc. Finally, current issues and prospects for the future are discussed.

Key message Sustainable winter production in lettuce requires freezing tolerant varieties. This study identified a wild-type allele of LsCBF7 that could contribute to freezing tolerance improvement in lettuce. Abstract Lettuce is one of the most consumed vegetables globally. While ideally grown in 13–21 °C, its cultivation extends into winter in milder climates. However, occasional freezing temperatures can significantly reduce yields. Therefore, the development of freezing-tolerant lettuce varieties has become a long-term goal of lettuce breeding programs. Despite its significance, our understanding of freezing tolerance in lettuce remains limited. Plants have evolved a coping mechanism against freezing, known as cold acclimation, whereby they can increase freezing tolerance when pre-exposed to low nonfreezing temperatures. The CBF pathway is well-known for its central role in cold acclimation. Previously, we identified 14 CBF genes in lettuce and discovered that one of them, LsCBF7, had a loss-of-function mutation. In this study, we uncovered that accessions from colder regions carried the wild-type allele of LsCBF7 and this allele likely contributed to increased freezing tolerance, with 14% of the lettuce population carrying this allele. Interestingly, in wild lettuce (L. serriola) that is considered a progenitor of cultivated lettuce, this wild-type allele was much more common, with a frequency of 90%. This finding suggests that this wild-type allele may have undergone negative selection during the domestication or breeding of lettuce. Our data strongly indicate that this allele could be linked to early bolting, an undesirable trait in lettuce, which may have driven the negative selection. While this wild-type allele shows promise for improving freezing tolerance in lettuce, it is crucial to decouple it from the early bolting trait to fully harness its potential in lettuce breeding.

The mechanical properties of skin change during aging but the relationships between structure and mechanical function remain poorly understood. Previous work has shown that young skin exhibits a substantial decrease in tissue volume, a large macro-scale Poisson’s ratio, and an increase in micro-scale collagen fiber alignment during mechanical stretch. In this study, label-free multiphoton microscopy was used to quantify how the microstructure and fiber kinematics of aged mouse skin affect its mechanical function. In an unloaded state, aged skin was found to have less collagen alignment and more non-enzymatic collagen fiber crosslinks. Skin samples were then loaded in uniaxial tension and aged skin exhibited a lower mechanical stiffness compared to young skin. Aged tissue also demonstrated less volume reduction and a lower macro-scale Poisson’s ratio at 10% uniaxial strain, but not at 20% strain. The magnitude of 3D fiber realignment in the direction of loading was not different between age groups, and the amount of realignment in young and aged skin was less than expected based on theoretical fiber kinematics affine to the local deformation. These findings provide key insights on how the collagen fiber microstructure changes with age, and how those changes affect the mechanical function of skin, findings which may help guide wound healing or anti-aging treatments.

It is well known that elliptic estimates fail for the $${\bar{\partial }}$$ ∂ ¯ -Neumann problem. Instead, the best that one can hope for is that derivatives in every direction but one can be estimated by the associated Dirichlet form, and when this happens, we say that the $${\bar{\partial }}$$ ∂ ¯ -Neumann problem satisfies maximal estimates. In the pseudoconvex case, a necessary and sufficient geometric condition for maximal estimates has been derived by Derridj (for (0, 1)-forms) and Ben Moussa (for (0, q )-forms when $$q\ge 1$$ q ≥ 1 ). In this paper, we explore necessary conditions and sufficient conditions for maximal estimates in the non-pseudoconvex case. We also discuss when the necessary conditions and sufficient conditions agree and provide examples. Our results subsume the earlier known results from the pseudoconvex case.

Objectives: Our aim was to identify the influence of heritage cultural factors and mainstream Australian cultural norms on young culturally and linguistically diverse (CaLD) immigrants’ alcohol and other drug (AOD) use attitudes, motives for use, and behaviors. Method: We conducted nine focus groups with 55 youth (aged 16–30; 22 female, 33 male). Participants were from diverse cultural backgrounds including India, Sri Lanka, Ethiopia, Eritrea, Sudan, Hazara-Afghanistan, Burma (Chin and Karen), Malaysia, Singapore, and China. They were first- (80%) and second-generation immigrants to Australia. Results: We constructed three overarching themes: bicultural conflict, freedom versus constraints, and the intersection of gender and culture. Although there were diverse responses, there was widespread recognition of perceived Australian norms around AOD use, particularly drinking alcohol. Our participants reported conformity motives that included fitting in with mainstream Australian culture. Drinking alcohol was also seen as a means for social bonding between immigrant and mainstream youth. Acculturation challenges of reconciling their heritage cultural identity with Australian identity contributed to problematic AOD use. Conclusions: Further research into the prevalence and predictors of AOD-related harm among CaLD youth in Australia is needed to tailor interventions that draw upon immigrant communities’ resilience and enhance positive adaptation outcomes.

Understanding and predicting the relationships between genotype and phenotype is often challenging, largely due to the complex nature of eukaryotic gene regulation. A step towards this goal is to map how phenotypic diversity evolves through genomic changes that modify gene regulatory interactions. Using the Prairie Rattlesnake (Crotalus viridis) and related species, we integrate mRNA-seq, proteomic, ATAC-seq and whole genome resequencing data to understand how specific evolutionary modifications to gene regulatory network components produce differences in venom gene expression. Through comparisons within and between species, we find a remarkably high degree of gene expression and regulatory network variation across even a shallow level of evolutionary divergence. We use these data to test hypotheses about the roles of specific trans-factors and cis-regulatory elements, how these roles may vary across venom genes and gene families, and how variation in regulatory systems drive diversity in venom phenotypes. Our results illustrate that differences in chromatin and genotype at regulatory elements play major roles in modulating expression. However, we also find that enhancer deletions, differences in transcription-factor expression, and variation in activity of the insulator protein CTCF also likely impact venom phenotypes. Our findings provide insight into the diversity and gene-specificity of gene regulatory features and highlight the value of comparative studies to link gene regulatory network variation to phenotypic variation.

Agricultural producers adopt management practices that positively and negatively affect the lives of non-producers in their communities. CRB has important environmental and human health implications, and local non-producers might have different perceptions and attitudes from agricultural producers about crop residue burning. In this paper, we use a multi-stakeholder approach to study the issue of crop residue burning (CRB). Survey data were collected from a sample of producers in Arkansas who burn crop residue and a sample of non-producers who resided in the same counties as the producers. Non-producers may not be willing to compensate producers at an amount that would reduce the use of CBR. Non-producers do not fully understand some of the benefits of CRB, like reduced tillage or equipment savings cost, and producers are less likely to perceive increased greenhouse gas (GHG) emissions as a negative externality associated with CRB. A multi-stakeholder approach can provide more depth and breadth to understanding complex decisions about farm management practices, and these results have implications for policies that incentivize adopting best farm management practices.

Introduction Methamphetamine detoxification before entering formal and longer term treatment may have a positive impact on treatment retention and success. Understanding geographic distribution of methamphetamine specialty detox services and differential access by race/ethnicity is critical for establishing policies that ensure equitable access across populations. Methods We used the Mental health and Addiction Treatment Tracking Repository to identify treatment facilities that offered any substance use detoxification in 2021 (N=2346) as well as the census block group in which they were located. We sourced data from the US Census Bureau to identify the percentage of a census block group that was White, Black, and Hispanic. We used logistic regression to model the availability of methamphetamine-specific detox, predicted by the percentage of a block group that was Black and Hispanic. We adjusted for relevant covariates and defined state as a random effect. We calculated model-based predicted probabilities. Results Over half (60%) of detox facilities offered additional detox services specifically for methamphetamine. Sixteen states had <10 methamphetamine-specific detox facilities. The predicted probability of methamphetamine-specific detox availability was 60% in census block groups with 0%–9% Black residents versus only 46% in census block groups with 90%–100% Black residents, and was 61% in census block groups with 0%–9% Hispanic residents versus 30% in census block groups with 90%–100% Hispanic residents. Conclusions During an unprecedented national methamphetamine crisis, access to a critical health care service was disproportionately lower in communities that were predominately Black and Hispanic. We orient our findings around a discussion of health disparities, residential segregation, and the upstream causes of the systematic exclusion of minoritized communities from health care.

The duck gastrointestinal tract (GIT) harbors an abundance of microorganisms that play an important role in duck health and production. Here, we constructed the first relatively comprehensive duck gut microbial gene catalog (24 million genes) and 4437 metagenome‐assembled genomes using 375 GIT metagenomic samples from four different duck breeds across five intestinal segments under two distinct rearing conditions. We further characterized the intestinal region‐specific microbial taxonomy and their assigned functions, as well as the temporal development and maturation of the duck gut microbiome. Our metagenomic analysis revealed the similarity within the microbiota of the foregut and hindgut compartments, but distinctive taxonomic and functional differences between distinct intestinal segments. In addition, we found a significant shift in the microbiota composition of newly hatched ducks (3 days), followed by increased diversity and enhanced stability across growth stages (14, 42, and 70 days), indicating that the intestinal microbiota develops into a relatively mature and stable community as the host duck matures. Comparing the impact of different rearing conditions (with and without water) on duck cecal microbiota communities and functions, we found that the bacterial capacity for lipopolysaccharide biosynthesis was significantly increased in ducks that had free access to water, leading to the accumulation of pathogenic bacteria and antibiotic‐resistance genes. Taken together, our findings expand the understanding of the microbiome signatures linked to intestinal regional, temporal development, and rearing conditions in ducks, which highlight the significant impact of microbiota on poultry health and production.

Using the Heckman framework, we develop profiles of households who purchase Greek yogurt and non-Greek yogurt and estimate own-price, cross-price, and income elasticities of demand. Attention is centered on the impacts of age, race, education, and ethnicity of the household head, household income, household size, region, the presence of children, and prices of Greek yogurt and non-Greek yogurt. This analysis rests on data acquired from Nielsen pertaining to 164,484 households over calendar years 2018–2020. Own-price elasticities are estimated to be −1.36 for Greek yogurt and −0.70 for non-Greek yogurt. Additionally, these yogurt products are not only substitutes but also necessities.

Background We investigated awareness and use of doxycycline post-exposure prophylaxis (doxyPEP) in the US. DoxyPEP has preventative benefits for bacterial STIs among people assigned male at birth. We considered how individual, interpersonal and social determinants of health, such as state-level LGBTQ equality, impact doxyPEP awareness. Methods We conducted an online snapshot cross-sectional survey in June 2023. Survey questions included demographics, sexual and substance use behaviours, and socio-environmental factors, and provided a short explanation of doxyPEP, with questions regarding prior awareness and use. Results Among a racially diverse sample of 196 participants (median age 33 years), 94% identified as cisgender men, 26% were aware of doxyPEP, whereas only 14 (7%) had ever used it. Factors significantly associated with awareness included being college educated (OR 2.50, 95% CI 1.09–5.74), a past year bacterial STI (OR 4.20, 95% CI 1.97–8.89), having discussed HIV pre-exposure prophylaxis with a health care provider (OR 3.88, 95% CI 1.99–7.57) and having taken HIV pre-exposure prophylaxis (OR 2.29, 95% CI 1.11–4.70). Socio-environmental factors associated with doxyPEP awareness included living in a large urban city (OR 2.14, 95% CI 1.12–4.10) and living in a state with higher levels of LGBTQ policy equality (OR 2.18, 95% CI 1.07–4.44). Conclusions Considering the disproportionate impact of bacterial STIs on men who have sex with men, especially those living in lower LGBTQ equality regions, such as the Southern US, our study emphasises how socio-environmental factors may limit awareness and uptake of novel biomedical approaches that have the potential to prevent morbidity and enhance sexual health.

Magnetic topological semimetals LnSbTe (Ln=lanthanide) have attracted intensive attention because of the presence of interplay between magnetism, topological, and electron correlations depending on the choices of magnetic Ln elements. Recently, varying Sb-Te composition has been found to effectively control the electronic and magnetic states in LnSbxTe2−x. With this motivation, we report the evolution of magnetic properties with Sb-Te substitution in NdSbxTe2−x+δ, (0≤x≤1). Our work reveals the interesting nonmonotonic change in magnetic ordering temperature with varying composition stoichiometry. In addition, reducing the Sb content x drives the reorientation of moments from in-plane (ab-plane) to out-of-plane (c-axis) direction that results in the distinct magnetic structures for two end compounds NdTe2 (x=0) and NdSbTe (x=1). Furthermore, the moment orientation in NdSbxTe2−x+δ is also found to be strongly tunable upon application of a weak magnetic field, leading to rich magnetic phases depending on the composition stoichiometry, temperature, and magnetic field. Such strong tuning of magnetism in this material establishes it as a promising platform for investigating tunable topological states and correlated topological physics.

The SnRK1 complex in plants regulates metabolism in response to environmental stresses and glucose depletion, for stress adaptation and energy homeostasis. Through phosphorylation of various targets, SnRK1 orchestrates intricate regulatory mechanisms involved in autophagy, nutrient remobilization, and TOR activity inhibition, showcasing its pivotal role in coordinating plant metabolism and stress responses. The present study aimed to identify members of the SnRK1 gene family in the maize genome and characterize them using bioinformatics and expression analyses under aphid feeding, drought, and cold stress. The focus of the study was to conduct a comprehensive analysis towards determining gene diversity of ZmSnRK1 genes, constructing intricate 3D structures, and identifying stress-related cis-elements. Four SnRK1 genes were identified, which were named ZmSnRK1.1, ZmSnRK1.2, ZmSnRK1.3, and ZmSnRK1.4. The SnRK1 proteins were found to have a distribution of conserved motifs; however, the distinction between monocots and dicots in the phylogenetic tree was clearly demonstrated. Analysis of the promoter region revealed that the ZmSnRK1 genes contain stress-related cis-elements. Compared to the control, ZmSnRK1.3 significantly upregulated in response to aphid feeding and cold stress, while ZmSnRK1.2 showed elevated expression under drought conditions. The expression of the other two genes under these treatments was generally unperturbed. The findings of this study are poised to establish a valuable scientific foundation for future research on the roles of the SnRK1 gene family in plants, providing valuable insights for enhancing genetic resilience to stress and optimizing yield traits.

Inspired by ballpoint pen, an optical biosensor is developed for detection of Salmonella using a mechanical step rotator with a dropper to greatly simplify operation, a high gradient magnetic field with immune magnetic nanobeads to specifically separate bacteria, and immune gold@platinum nanozymes with a smartphone to sensitively detect bacteria. First, the preloaded bacterial sample is drawn by the dropper to react with the immune magnetic nanobeads through repeated squeezing and releasing of the dropper, and the rotator is successively rotated and the dropper is repeatedly squeezed and released to achieve mixing of the bacteria, magnetic nanobeads and gold@platinum nanozymes, followed by magnetic separation to remove the background. Then, the conjugates are effectively washed with skim milk and ultrapure water, and the substrate are rapidly catalyzed into the product. Finally, the blue product is photographed and analyzed using a smartphone to obtain the Salmonella concentration. This biosensor could detect Salmonella as low as 56 CFU/mL in ~ 25 min.