Flexible Microelectrode-Based Impedance Immunosensor for Rapid Detection of \u3ci\u3eE. coli\u3c/i\u3e O157:H7

Abstract 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. Escherichia coli 0157:H7, recognized as one of the principal causes of foodborne illness, poses a considerable risk to food safety. The primary objective of this investigation is to devise a flexible microelectrode-based immunosensor capable of swiftly identifying E. coli O157:H7 cells without the need for incubation in a pure culture environment. In the development of the biosensor, the gold electrode (composed of 50% Au) underwent an initial coating process involving 2-aminoethanethiol/cysteamine, followed by functionalization with glutaraldehyde to serve as a linker, and subsequent immobilization with anti-E. coli polyclonal antibodies (pAbs). The determination of the optimal concentration of cysteamine and glutaraldehyde for sensor development revealed an optimal concentration of 20 mg/mL. Upon interaction between anti-E. coli pAbs and E. coli O157:H7, a substantial increase in impedance amplitude from 2.7 to 6.93 kΩ was observed, highlighting the efficacy of the immunosensor in detecting the target pathogen when compared to a bare electrode. Furthermore, the developed immunosensor exhibited the capability to detect E. coli O157:H7 cells with a detection limit ranging from 101 to 103 CFU/mL without the requirement of an incubation period. Visual confirmation of successful binding of E. coli O157:H7 onto the flexible microelectrode-based immunosensor was achieved through scanning electron microscopy imaging, providing insights into the adherence of bacterial cells to the microelectrode surface. Keywords: Foodborne pathogens, flexible biosensors, electrochemical immunosensor; rapid detection; Escherichia coli O157:H

Susceptibility Analysis of Flash Flood in Jeddah City, Saudi Arabia, Using a GIS-Based Analytical Hierarchy Process

Floods rank among the most devastating natural hazards on Earth, posing significant threats to human society across various geographies, including arid regions such as Saudi Arabia. In Saudi Arabia, Jeddah is the second largest city in terms of population with more than 4.5 million residents. The city experiences long and arid summers and short, dry, and windy winters. As the severity and frequency of floods continue to increase, there is a growing demand for improved flood risk assessment to mitigate damage to lives and properties. Given the complex nature of flood evaluation and prediction, a systematic criteria-based methodology, such as the Analytical Hierarchy Process (AHP), offers a robust solution. This study integrates the AHP with a Geographic Information System (GIS) to model flash flood risk hazards in Jeddah, Saudi Arabia. Key parameters for this evaluation included precipitation, elevation, slope, proximity to drainage networks, land cover, and lithology. A pairwise comparison was conducted to rank these criteria by order of magnitude in flood contribution. Four susceptibility grades – ranging from Low to Very High – were identified to represent flood hazard likelihood. The findings show that the eastern and central parts of Jeddah, particularly areas leading to the coast, are identified as the most vulnerable areas to flash flooding due to their proximity to natural water channels and their low-lying, intermittent topography, which creates valleys. Obviously, the rapid urbanization of Jeddah contributes also to flash flooding caused by seasonal downpours. Local authority should develop coping strategies, such as widening drainage systems and reducing paved surface areas in highly susceptible zones, to mitigate future flood risks effectively

Heinrich Krieger and the Nazi Vision of the United States

On June 5, 1934, seventeen Nazi lawyers, jurists, scholars, and officials met to discuss how Nazi Germany would go about identifying and persecuting their Jewish population. This crucial meeting would lay the foundation for the Nuremberg Laws that were later created and passed in 1935. From the records of this meeting we know that US race laws concerning its black and Indian population was used as a model for the Nazi lawyers and much of the information on US race laws was obtained from research conducted by a Nazi scholar named Heinrich Krieger that was influential during the meeting. Before this meeting Heinrich Krieger had spent a year at the University of Arkansas as a foreign exchange student during the 1933-1934 school year. While in Arkansas Krieger would partake in multiple campus activities and write a seminar paper on Nazi German labor policies as an apologist on behalf of Germany to the US. However while spending time in Arkansas Krieger would begin to notice race relations in the state that would lead him to study US race laws that would be used by Nazi officials to create the Nuremberg laws. This thesis will study the development of Krieger while a student in Arkansas to reveal how Krieger and the Nazi party had no master plan to use the US and its race laws as a model for the Nuremberg laws. Rather by examining Krieger\u27s development from labor scholar to race scholar, we can see how Krieger and Nazi officials were opportunists who came across US race laws and saw its potential. Also, Arkansas and its race laws and race relations will be examined to learn how the state influenced Krieger\u27s research and understanding of US race laws

Overlook

The project consists of an introductory essay, three main short story sections, and finally the titular novella as the anchor. I found inspiration in Tommy Orange’s There There to open with a nonfiction prologue that contextualizes the fiction. The essay encapsulates my reckoning with place and the realization that I belong in a rich lineage of Southern literature in more ways than one. The essay, like the thesis as a whole, is a meditation on my inheritance of storytelling—the complex relationship between life and fiction, what we remember, who remembers what, and how we remember it. My work reflects my journey in the program: At first feeling apart from or ashamed of the place I’m from, to reflecting on my origins, and ending with a symbolic embracing of my identity as an Arkansan writer. Foregrounded by each of the “Arkansas Traveler” sections, the short stories follow that thematic arc while interrogating a blend of mythologies. The final section, “Overlook,” is the natural progression from acceptance to celebration where I set out to create an original Southern mythos of my own

Unbridled Healing: Identifying the Barriers of Equine-Assisted Therapy

Despite the documented benefits of equine-assisted therapy (EAT) for mental health conditions, this complementary approach remains underutilized. This qualitative study investigated barriers preventing wider EAT implementation by examining challenges faced by clients, facilities, and volunteers. Data collected through open-ended surveys from 33 participants and the researcher\u27s autoethnographic observations revealed eight common barriers: Accessibility (48 mentions), Money (43), Time (30), Awareness (23), Physical Factors (13), Relationships (13), Risk (13), and Weather (7). Clients identified financial constraints as their primary barrier, particularly insurance limitations. Facilitators struggled most with accessibility challenges, including lack of resources, trained staff, suitable horses, and appropriate facilities. Volunteers faced significant time constraints and communication difficulties. Novel findings included communication issues for volunteers, relationship barriers affecting retention, physical limitations to participation, and weather-related constraints affecting all stakeholder groups. The study\u27s findings support advocacy efforts to address these barriers and potentially expand EAT access to more diverse populations.https://scholarworks.uark.edu/hnrcsturpc25/1046/thumbnail.jp

The expression of intestinal tight junction proteins induced by 1,25-dihydroxyvitamin D3-glycosides supplementation to reduce bacterial chondronecrosis with osteomyelitis lameness in broilers

Bacterial Chondronecrosis with Osteomyelitis (BCO) is a leading cause of lameness in broiler chickens, impacting animal welfare and commercial poultry production. Supplementation using organic trace minerals, vitamin D, probiotics, and prebiotics has been studied to mitigate BCO lameness incidences in broiler chickens. Our previous study demonstrated that feeding Panbonis®-G-1,25(OH)2D3 from Solanum glaucophyllum, containing 1 µg/kg G-1,25(OH)2D3, to broilers for the first 28 days of their production cycle reduced BCO lameness by approximately 50%. In this study, we investigated the impact of 1,25-dihydroxy vitamin D3 supplementation on the expression of tight junction (TJ) proteins to further understand its mode of action in safeguarding birds from BCO disease. We measured the mRNA expression of claudins (CLDN1 and CLDN5), occludin (OCLDN), and zonula occludens-1 (ZO-1) in the epithelial barrier of the respiratory and gastrointestinal tracts at 14, 21, and 28 days post-hatch. RNA extraction was performed using the QIAGEN RNeasy Plus Mini Kit, and gene expression was analyzed with RT-qPCR for key TJ genes, with GAPDH serving as a housekeeping gene. Expression levels were quantified using the ΔΔCt method to assess differences between experimental and control groups. The results revealed a time-dependent pattern of TJ gene expression, with no and limited expression at days 14 and 21, respectively, and significant upregulation at day 28. T3 (1 µg/kg for 21 days) primarily influenced the gastrointestinal tract, while T4 (1 µg/kg for 28 days) had the strongest impact on the respiratory tract. Notably, CLDN1, OCLDN, and ZO-1 showed significant upregulation at day 28 in both the ileum and jejunum, whereas the trachea exhibited substantial changes only in response to T4 supplementation. These findings suggest that TJ protein activity is regulated developmentally and tissue-specifically, highlighting the potential role of gut and respiratory barrier integrity in BCO susceptibility. Understanding these molecular mechanisms contributes to developing targeted nutritional strategies to reduce lameness in broiler chickens and informs potential genetic markers for selective breeding programs