Mississippi State University
  • Starkville, United States
Recent publications
This paper presents the design of a single-phase, single-stage line impedance stabilization network (LISN) for medium-voltage (MV) applications. More than 1 kV rated widebandgap (WBG) power semiconductor switches are increasingly utilized in new, emerging power electronics energy systems to improve power density and efficiency. However, due to inherently fast-switching speeds, WBG switch modules emit considerable electromagnetic interference (EMI) (e.g., common mode (CM) or differential mode (DM)). State-of-the-art offers standardized LISN solutions to validate and certify the new energy system for electromagnetic compatibility (EMC). However, most are for low voltage applications (i.e., < 1 kV). MV LISNs (i.e., > 1 kV) are rare until recently and literature does not provide sufficient guidelines for designing and characterizing such devices. It has been a critical challenge for many scientists and engineers to reliably certify the emerging MV energy systems (e.g., electric ships and aircraft). This paper addresses such a technology gap. Specifically, a CISPR 16-1-2 compliant 50Ω/50μH LISN with 1.5kV, 75A and 30MHz measurement capability has been proposed. Detailed performance study versus non-linear parasitic parameters variations in MV inductors and capacitors have been done. Based on new understandings, novel techniques to intuitively mitigate unwanted parasitic have been proposed to develop the proposed LISN successfully. Thorough characterization of important LISN parameters are presented and factors influencing them are analyzed. A rigorous analysis, experimental tests, and in-depth comparisons over state-of-the-art have been made to validate the effectiveness. This is done through the state-of-the-art 300kVA MV EMI testbed
Deep-space habitation presents unique challenges in operating complex control-based systems in distant and disruptive environments far from Earth. The capability to handle unforeseen situations and manage system health is crucial for resilient operations in deep space. Trusted health management strategies operational on the International Space Station (ISS) heavily rely on ground control support. These strategies must adapt to cope with sizable communication delays imposed by the infrastructure limitations or light distances that separate ground control and the habitat. Alternative approaches that increase reliance on artificial intelligence-based onboard autonomy are constrained by limited onboard computing and risks associated with human-system integration. There is an increased need to study the design and architecture of the health management system (HMS) of such complex systems to address autonomy challenges for deep-space habitation. This paper presents a model-based HMS testbed developed at the Resilient Extra-Terrestrial Habitats Institute that is part of the HabSim, a system-of-systems simulator of a smart habitat. The testbed is designed to facilitate performance assessment of critical health management functions essential to enable fault-management autonomy, situational awareness, and interface-based mission control. In this paper, the HMS testbed is motivated and placed within HabSim, the architecture of its components is detailed, and the testbed features are demonstrated through an illustrative example. The lessons learned in developing this testbed that may be useful for others seeking to solve similar problems are also discussed.
Prior work on computer-vision wood identification (CVWID) for North American hardwoods yielded two independent deep learning models – a 22-class model for diffuse-porous woods and a 17-class model for ring-porous woods – but did not address semi-ring-porous woods nor provide a CVWID solution for an unknown specimen without a human first determining which model to deploy. As untrained human operators would lack the anatomical proficiency to differentiate among porosity domains, it is necessary to develop a consolidated model that can identify diffuse-, ring-, and semi-ring-porous woods. Previous research suggests that prediction accuracy might decrease as class number grows. A potential strategy to reduce the number of classes a CVWID system must consider at a time is to hierarchically deploy a cascade of models. In pursuit of a unified model that can cover North American hardwoods of all porosity types, this study compared the accuracies of a consolidated 39-class (ring- + diffuse-porous) model and a consolidated 42-class (ring- + diffuse- + semi-ring-porous) model with a two-tiered, cascading model scheme whereby images are first differentiated into three porosity domain classes and then again into only those taxonomic classes with that porosity. The results showed that the cascading model scheme can mitigate the accuracy reductions incurred by the 42-class model and nearly eliminate the occurrence of cross-domain misidentifications.
In the heart, ion channels generate electrical currents that signal muscle contraction through changes in intracellular calcium concentration, i.e., [Ca ²⁺ ]. The cardiac ryanodine receptor type 2 (RyR2) is the predominant ion channel responsible for increasing intracellular [Ca ²⁺ ] by releasing Ca ²⁺ from the sarcoplasmic reticulum (SR). Timely Ca ²⁺ release is necessary for appropriate cardiac function, and dysfunction can cause or contribute to life‐threatening diseases such as arrhythmia. Quantification of SR‐Ca ²⁺ release in the form of sparks and waves can provide valuable insight into RyR2 opening, and factors that influence or regulate channel function. Here, we provide a series of protocols that outline processes for (1) obtaining high‐quality isolated cardiomyocytes, (2) preparing samples for experimentally investigating factors that influence RyR2 function, and (3) data acquisition and analysis. Notably, our protocols leverage the potency of the recently developed myosin ATPase inhibitor, Mavacamten. This affords the opportunity to characterize the effects of small molecules or reconstituted proteins/enzymes on RyR2‐Ca ²⁺ release events across a range of [Ca ²⁺ ]. © 2024 Wiley Periodicals LLC. Basic Protocol 1 : Cardiomyocyte isolation from mouse Basic Protocol 2 : Preparation of cardiomyocytes for Ca ²⁺ imaging Basic Protocol 3 : Confocal microscopy and quantitative Ca ²⁺ analysis using SparkMaster 2
The application of exogenous RNA for gene-silencing strategies has gained significant traction in agriculture, offering a highly efficient and eco-friendly alternative to conventional plant protection methods. This success has been driven by advances in biotechnology, from the design of long double-stranded RNA (dsRNA) and small interfering RNA (siRNA) molecules to the development of nanocarrier systems that address the challenge of RNA delivery into plant cells. In particular, polymer-based nanocarriers have emerged as a promising solution for enhancing the stability and delivery efficiency of RNA molecules. This review provides a comprehensive overview of the current state of research on the use of polymeric nanocarriers in RNA interference (RNAi) systems for crop protection. It examines key technological developments that have enabled the effective delivery of dsRNA/siRNA to target organisms, with a focus on the unique advantages polymers offer as carriers. Recent studies highlight significant progress in the preparation, characterization, and application of polymeric nanocarriers for RNA encapsulation and delivery. The review also explores the environmental and health challenges posed by these technologies, emphasizing the need for sustainable approaches in their development. Specifically, the production of nanocarriers must adhere to the principles of green chemistry, prioritizing chemical modification routes that reduce harmful residues, such as toxic solvents. Finally, this paper discusses both the current challenges and future prospects of using polymer-based nanocarriers in sustainable agriculture, offering critical insights into their potential to transform crop protection through RNAi technologies.
Flowering rush ( Butomus umbellatus L.) is an emergent perennial monocot that has invaded aquatic systems along the U.S. - Canadian border. Currently, there are two known cytotypes of flowering rush, diploid and triploid, within the invaded range. Although most studies have focused on the triploid cytotype, little information is known about diploid plants. Therefore, phenology and resource allocation were studied on the diploid cytotype of flowering rush in three study sites (Mentor Marsh, Ohio; Tonawanda Wildlife Management Area, New York; and Unity Island, New York) to understand seasonal resource allocation, environmental influences on growth, and to optimize management strategies. Samples were harvested once a month from May to November at each site from 2021 to 2023. Plant metrics were regressed to air temperature, water temperature, and water depth. Aboveground biomass peaked from July-September and comprised 50 to 70% of total biomass. Rhizome biomass peaked from September to November and comprised 40 to 50% of total biomass. Rhizome bulbil densities peaked from September to November at 3,000 to 16,000 rhizome bulbils m ⁻² . Regression analysis resulted in strong negative relationships between rhizome starch content and air temperature (r ² =0.52) and water temperature (r ² =46). Other significant, though weak, relationships were found including a positive relationship between aboveground biomass and air temperature (r ² =0.17), a negative relationship between rhizome bulbil biomass and air temperature (r ² =0.18) and a positive relationship between leaf density and air temperature (r ² =0.17). Rhizomes and rhizome bulbils combined stored up to 60% of total starch and present a unique challenge to management as these structures cannot be reached directly with herbicides. Therefore, management should target the aboveground tissue before peak production (July) to reduce internal starch storage and aim to limit regrowth over several years.
Diseases of soybean (Glycine max L.) caused by species of Diaporthe have resulted in estimated yield losses totaling $248.2 million in the U.S. over the past 10 years. To effectively manage species of Diaporthe, it is important to use an integrated approach. In this study, we evaluated the in vitro sensitivity of isolates of the soybean pathogens Diaporthe aspalathi, D. caulivora, and D. longicolla from 18 U.S. states to difenoconazole (a demethylation inhibitor fungicide) and fluopyram (a succinate dehydrogenase inhibitor fungicide). The fungicides were incorporated into 2% water agar (WA) in petri dishes at various concentrations. A mycelial plug of each isolate (n=59 for difenoconazole and n=55 for fluopyram) obtained from a 7-day-old culture was placed at the center of the WA and incubated in the dark. After five days for D. caulivora and D. longicolla, and eight days for D. aspalathi, the colony diameter was measured, and the corresponding percent inhibition and effective concentration at which 50% mycelial growth was inhibited (EC50) were determined. Significant differences in EC50 values (P<0.0001) were observed among the isolates of D. aspalathi (0.227 µg/ml), D. caulivora (0.130 µg/ml), and D. longicolla (1.860 µg/ml) for difenoconazole. Similarly, for fluopyram, the EC50 values varied significantly (P<0.001) among the D. aspalathi (2.233 µg/ml), D. caulivora (1.610 µg/ml), and D. longicolla (0.347 µg/ml) isolates. This study established sensitivity profiles for difenoconazole and fluopyram fungicides for D. aspalathi, D. caulivora, and D. longicolla, and provides valuable information that may help in the development of Diaporthe disease management program.
Background Testing for insulin dysregulation (ID) in horses is commonly performed to guide management and therapeutic strategies. Objectives To evaluate a newly developed glycemic pellets challenge (GPC) and compare results to those obtained using the low‐dose oral sugar test (OST). Animals Twenty‐four adult horses with unknown insulin status. Methods A randomized crossover trial was performed. Horses underwent GPC (0.5 g glycemic carbohydrates/kg body weight) and OST (0.15 mL corn syrup/kg body weight) 7 days apart. Feed was withheld before testing and blood samples were collected at T0, T60, T120, and T180 minutes for GPC and at T0, T60, and T90 minutes for OST. Blood glucose concentration was measured using a point‐of‐care glucometer and insulin by radioimmunoassay. Comparisons were made using nonparametric tests, linear regression, and Bland‐Altman agreement analysis. Results Eighteen horses consumed >85% of the GPC pellets within 10 minutes and had acceptable OST results. Maximum glucose (P = .02) and insulin (P = .007) concentrations were significantly higher for GPC compared with OST. Time to maximum insulin concentration (Tmax[ins]) varied within and between tests and neither Tmax[ins] (P = .28) nor maximum insulin concentration (P = .46) was correlated with the time horses took to consume pellets. Conclusions The GPC is well tolerated and may offer another diagnostic testing modality for ID. Blood glucose and insulin concentrations increase during GPC and reach higher concentrations than observed with low‐dose OST. The Tmax[ins] varied for GPC and OST, emphasizing the importance of identifying the optimal time range for the collection of samples to capture diagnostically relevant changes in insulin concentration.
The understanding of clustering aspects at the ground state of nuclei and in fast rotating ones within the framework of covariant density functional theory has been reviewed and reanalyzed. The appearance of many exotic nuclear shapes in nuclear chart can be inferred from combined analysis of nodal structure of the densities of the single-particle states and the evolution of such states in the Nilsson diagram with deformation and particle number. Such analysis which is supported by fully self-consistent calculations allows to predict the existence of nuclear configurations with specific shape or cluster properties at ground state and at high spin. For example, it indicates that in a given shell with principal quantum number N only the lowest in energy two-fold degenerate deformed state can contribute to the formation of linear chain α cluster structures.
We investigate the impact of loneliness on consumer disposition of used, yet still useful possessions. Both loneliness and how consumers handle used products have emerged as important societal and research topics. While existing literature primarily addresses how loneliness influences product acquisition, our research delves into its effect on the disposition of used products. Studies 1–3 demonstrate that lonely consumers are less willing to let go of their used possessions because they form stronger self‐product attachments. Study 4 further examines an unstudied factor that moderates the effect—the relational meanings of a product (whether the item was a gift from someone else or acquired by the owner themselves). Our work contributes to the loneliness literature by showing how lonely consumers attach to possessions with different relational meanings. We also contribute to the growing disposition literature by investigating the joint influence of the disposers' traits and product characteristics. Our findings suggest communication strategies to facilitate lonely consumers' decluttering and disposal decisions.
We propose a two-stage estimation procedure for a copula-based model with semi-competing risks data, where the non-terminal event is subject to dependent censoring by the terminal event, and both events are subject to independent censoring. With a copula-based model, the marginal survival functions of individual event times are specified by semiparametric transformation models, and the dependence between the bivariate event times is specified by a parametric copula function. For the estimation procedure, in the first stage, the parameters associated with the marginal of the terminal event are estimated using only the corresponding observed outcomes, and in the second stage, the marginal parameters for the non-terminal event time and the copula parameter are estimated together via maximizing a pseudo-likelihood function based on the joint distribution of the bivariate event times. We derived the asymptotic properties of the proposed estimator and provided an analytic variance estimator for inference. Through simulation studies, we showed that our approach leads to consistent estimates with less computational cost and more robustness than the one-stage procedure developed in Chen YH (Lifetime Data Anal 18:36–57, 2012), where all parameters were estimated simultaneously. In addition, our approach demonstrates more desirable finite-sample performances over another existing two-stage estimation method proposed in Zhu H et al., (Commu Statistics-Theory Methods 51(22):7830–7845, 2021) . An R package PMLE4SCR is developed to implement our proposed method.
Aggregation behavior is pervasive across a broad range of animals and the outcome of this behaviour has both risks and rewards. Large aggregations of animals are a distinctive characteristic of Migratory Caribou (Rangifer tarandus Linnaeus, 1758), primarily in response to the environment factors such as predation, although caribou may also aggregate during high summer temperatures, likely in an effort to mitigate parasitic biting flies. To see if caribou in the Cape Churchill Caribou Herd of the Eastern Migratory caribou (Rangifer tarandus groenlandicus Borowski, 1780) Designatible Unit, also displayed aggregation behavior in relation to warmer summer temperatures, we collected trail camera photos with associated temperature readings during the summer period (May to September) from 2017 to 2020 in their summer range in Wapusk National Park, Manitoba, Canada. We found that summer caribou aggregation size was positively associated with ambient temperature, with aggregations increasing in size as temperature increased. The mechanism behind this behaviour should be investigated, as we predict more frequent and large caribou aggregations as summer temperatures continue to warm.
The accident involving the Chernobyl nuclear power plant has become fodder for TV programs, movies, books, and video games. But the question must be asked, how accurate are these mediums to the accident and area that they portray? The Chernobyl accident not only led to the deaths of thousands of people and displaced thousands of others, but it permanently impacted the environment around the town of Pripyat and the surrounding areas. This area is known as the exclusion zone and is still restricted today, due to the high levels of radiation. One game that does its best to accurately depict the environmental changes of the exclusion zone is Chernobylite. While having fictional elements, the team creating the game conducted 3D imaging of the exclusion zone, allowing players to view the exclusion zone without traveling to Ukraine. This chapter examines how games are being used in academic studies; the history of Chernobyl and the environmental impact of the actual event; the portrayal of Chernobyl in games and media in recent years; and what Chernobylite does differently than its predecessors. By doing so, it is possible to see how Chernobylite has indeed shed a new light in the exclusion zone.
Rice (Oryza sativa L.) producers in the Mid-south are experiencing difficulties with herbicide-resistant weeds such as barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.]. As a result, methods that can alter E. crus-galli ecology are needed. This research evaluated the ecological implications of rice cultivar and row widths on crop and E. crus-galli growth. Overall, for E. crus-galli, as the row width increased, greater density, panicle counts, and seed production occurred. Echinochloa crus-galli density was 120% greater in a 38-cm row width than the 13-cm row width at the preflood rice stage. Reduced early-season rice canopy coverage in the wider row widths allowed for increased E. crus-galli densities. At the preharvest stage, E. crus-galli panicle counts were similar for the 13- and 19-cm rows. Row width did not affect rice yield, indicating wider row widths could be feasible agronomically, but additional weed management efforts would be needed because greater ecological advantages were obtained in narrower rows. Less E. crus-galli seed production occurred in competition with hybrid cultivars compared to inbred cultivars. Overall, the standard row width (19-cm) and hybrid cultivars would provide the greatest ecological advantage over E. crus-galli.
Nanoparticles (NPs) offer significant promise as drug delivery vehicles; however, their in vivo efficacy is often hindered by the formation of a protein corona (PC), which influences key physiological responses such as blood circulation time, biodistribution, cellular uptake, and intracellular localization. Understanding NP-PC interactions is crucial for optimizing NP design for biomedical applications. Traditional approaches have utilized hydrophilic polymer coatings like polyethylene glycol (PEG) to resist protein adsorption, but glycopolymer-coated nanoparticles have emerged as potential alternatives due to their biocompatibility and ability to reduce the adsorption of highly immunogenic proteins. In this study, we synthesized and characterized glycopolymer-based poly[2-(diisopropylamino)ethyl methacrylate-b-poly(methacrylamidoglucopyranose) (PDPA-b-PMAG) NPs as an alternative to PEGylated NPs. We characterized the polymers using a range of techniques to establish their molecular weight and chemical composition. PMAG and PEG-based NPs showed equivalent physicochemical properties with sizes of ∼100 nm, spherical morphology, and neutral surface charges. We next assessed the magnitude of protein adsorption on both NPs and catalogued the identity of the adsorbed proteins using mass spectrometry-based techniques. The PMAG NPs were found to adsorb fewer proteins in vitro as well as fewer immunogenic proteins such as Immunoglobulins and Complement proteins. Flow cytometry and confocal microscopy were employed to examine cellular uptake in RAW 264.7 macrophages and MDA-MB-231 tumor cells, where PMAG NPs showed higher uptake into tumor cells over macrophages. In vivo studies in BALB/c mice with orthotopic 4T1 breast cancer xenografts showed that PMAG NPs exhibited prolonged circulation times and enhanced tumor accumulation compared to PEGylated NPs. The biodistribution analysis also revealed greater selectivity for tumor tissue over the liver for PMAG NPs. These findings highlight the potential of glycopolymeric NPs to improve tumor targeting and reduce macrophage uptake compared to PEGylated NPs, offering significant advancements in cancer nanomedicine and immunotherapy.
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6,662 members
Arazais D. Oliveros
  • Department of Psychology
Cliff Mckinney
  • Department of Psychology
Robert Meyer
  • College of Veterinary Medicine
Vladimir J. Alarcon
  • Northern Gulf Institute (NGI)
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Starkville, United States
Head of institution
Dr. Mark Keenum