UARK (University of Arkansas )
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Small Angle X-ray Scattering Studies of Collagenase H Mutant, ColH-E416Q
No full textCollagenase H (ColH) from Hathewaya histolytica plays a central role in collagen degradation through endopeptidase and carboxytripeptidase reactions. To better understand how its domain architecture supports these functions, we examined the solution structure of a catalytically inactive mutant, ColH-E416Q, using small-angle X-ray scattering (SAXS). The E416Q mutant is catalytically inactive because the glutamate residue at position 416, which normally functions as a general acid/base during catalysis, is replaced by glutamine—an amide that cannot donate or accept protons effectively, thus disabling the proton transfer steps essential for peptide bond hydrolysis. SAXS results indicate that the E416Q substitution leaves overall domain architecture and conformational behavior intact with comparative differences in dynamics. The E416Q mutation in ColH selectively abolishes catalytic activity while preserving substrate binding, making it a valuable tool for structural and mechanistic studies. By stabilizing enzyme–substrate complexes that would otherwise be transient, ColH-E416Q offers a strategic platform for capturing intermediate snapshots of collagen unwinding and cleavage. This presents a potential avenue for the development of novel collagenase inhibitors that target non-catalytic sites; an approach of particular interest given the close resemblance between bacterial catalytic sites and those of human matrix metalloproteases (MMPs), a similarity that made earlier inhibitor designs unsuitable due to anticipated side effects. These findings deepen our mechanistic understanding of bacterial collagenolysis and provide a structural basis for developing next-generation inhibitors or engineered collagenase variants with improved specificity
Effect of Dietary Tryptophan Supplementation and Heat Stress on Pasture Broiler Welfare and Performance
No full textPasture-raised broiler chickens face temperature extremes that can threaten welfare. In the study, we evaluated whether a 0.26 % tryptophan-supplemented diet (T) improved heat stress (HS) resilience in Ross-708 broilers raised on pasture. At D14, birds began the T or remained on the control diet (C) and were moved outdoors. On D20 and 41, half of each group underwent six-hour HS; the remainder stayed under thermoneutral (TN) conditions. Weekly body weight, feed intake on D20 and D41 were recorded, and fear was measured using the Tonic Immobility (TI) test. Neither diet nor HS affected body weight. However, tryptophan supplementation resulted in higher feed conversion ratios (FCR) in Week 6 and cumulatively from D14 to 42 compared to C, suggesting reduced feed efficiency. On D20 and 41, HS significantly reduced feed intake during HS, regardless of diet. At both ages, HS did not significantly affect fear behavior, though HS birds numerically remained immobile longer on D22, suggesting increased fearfulness. On D15, C birds showed shorter latency to first head movement compared to T birds, indicating heightened vigilance; these effects did not persist following HS on D22. Under HS, birds spent more time sitting, panting, and wing spreading, and less time standing and eating compared to TN. Within HS pens, T birds exhibited more simultaneous panting and wing spreading (PAWS) than controls, implying greater thermal stress. Age affected thermoregulatory behavior during HS, where younger birds on D20 were more active and utilized convective cooling (walking, wing spreading, PAWS), whereas older birds on D41 relied more on evaporative cooling behaviors, including panting and sitting behaviors. Overall, tryptophan supplementation did not positively affect growth performance or reduce fear before or after HS; instead, it may have exacerbated thermal stress
Effect of Marination and Storage Time on The Properties and Meat Quality of Broiler Breast
No full textAbstract The poultry industry has implemented numerous methods, as marination and aging, to improve meat quality and satisfy consumer demands. Three experiments were developed to assess the effects of vacuum tumble marination and aging on the proteins of chicken breast. These experiments utilized 0.75 % sodium chloride, 0.45 % phosphate, and water in a marinade. In experiment one, 270 fillets were allocated into six treatment groups, each comprising 45 fillets. Six days of storage time were used, marinating and storing the fillets in each group at a temperature of 4°C. Following each day of storage period, the fillets underwent a 15-minute marinade utilizing the vacuum tumble method, followed by an additional 24-hour storage period prior to analysis. The texture, drip loss %, marination pick-up %, purge %, and cook loss % were significant parameters assessed using a texture analyzer. In the second experiment, fillets were marinated and stored for 2, 4, or 6 days of storage at 4C and compared to fillets that were non-marinated and stored for the same periods, over three replications. Changes in pH, color, and the identical meat quality parameters as the initial experiment were assessed. This facilitated the evaluation of the marinade\u27s effects during different storage durations. In the third experiment, marinated chicken breasts with spaghetti meat myopathy were compared with neither marinated nor non-marinated fillets. As in previous experiments, thirty affected breasts were marinated utilizing the identical method and marinade. The assessment centered on the following parameters: pH, color before to and after to marination, drip loss %, pick-up %, purge %, cook loss %, and texture. In experiment one, the drip loss % tended to increase as storage time passed, whereas the purge percentage decreased. Cook loss % also increased throughout the six days of storage, indicating that meat quality deteriorated with time. The texture analysis revealed marginal variations throughout the days, with no discernible patterns. Overall, non- marinated fillets exhibited a greater loss in the second experiment compared to their marinated counterparts. Although the initial pH values of the fillets did not differ significantly, they exhibited a higher pH level after marinating. The color analysis results conducted before and after marination indicated that marinated fillets exhibited marginally reduced initial L* and b* values, but substantial variations after marination, which indicated enhanced color retention. Overall, non-marinated fillets suffered the greatest loss in the third experiment, in comparison to fillets treated with spaghetti meat myopathy and conventional marinated fillets. The marinated fillets exhibited higher pH post-marination, suggesting enhanced pH stability. There were notable variations in color values following marination, whereby marinated fillets exhibited superior color retention on average. In general, the outcomes of these experiments demonstrate that vacuum tumble marination is an efficacious method for enhancing the consistency of color, pH stability, and water retention of poultry meat, which are critical determinants of meat quality. Aging and marination are crucial processes in preserving and improving meat quality throughout the storage period. Key Words: marination, breast, quality, storage, color, pH
Co-Creating Play:Utilizing Comics to Potentialize Participatory Self-Determination in Marginilized Young Adults
No full textStorytelling has long served as a vital mechanism for preserving cultural heritage, transmitting values, and fostering intergenerational connection (Moeshlin, 2024). Despite this significance, graphic narratives such as comics and graphic novels have been historically marginalized—dismissed as trivial “children’s media” or reduced to entertainment rather than recognized as culturally resonant tools (McCloud, 1993). This marginalization intensified as comics evolved to depict adult themes and, at times, harmful stereotypes, triggering social backlash that stigmatized their utility for younger audiences (Segran, 2020). Consequently, scholarly exploration of comics’ therapeutic potential has stagnated, hindered by the medium’s tumultuous history. This study bridges this gap by investigating how participatory-designed narrative tools can harness comics’ unique strengths to support mental health. Grounded in Self-Determination Theory (SDT; Ryan & Deci, 2000), which identifies autonomy, competence, and relatedness as pillars of psychological well-being, the research integrates principles of narrative therapy, play therapy, and participatory design (PD) into a novel framework termed comicboarding. By centering users as co-creators in the design process, this approach seeks to empower marginalized individuals—particularly young adults aged 16-20 in Black communities—to engage in self-expressive storytelling that addresses their psychological needs. The primary outcome is a prototype narrative comic toolbook designed to guide users in crafting visual narratives, fostering emotional well-being through creative agency and participatory engagement. This work advances comics’ recognition as legitimate therapeutic tools while offering practical, culturally responsive strategies for mental health intervention. Ultimately, it underscores the transformative potential of user-centered, visually driven storytelling to amplify marginalized voices and promote healing
Simulation- and Machine Learning-based Methods for Inland Waterway Operation and Maintenance Decision-making
No full textThe U.S. inland waterway transportation system (IWTS) is an essential part of the country\u27s multimodal freight transportation network. In addition to seasonal droughts and floods, the operations of the IWTS may be disrupted by random malfunctions and scheduled maintenance of its critical components. Among these critical components, locks play a key role in the operation of navigable inland waterways, and lock-induced disruptions to the supply chains of related industries, such as agriculture and manufacturing, often result in significant economic losses. To assess the performance of the U.S. IWTS, we develop a PyNetLogo simulation tool to capture the movements and delays of cargoes considering various sources of uncertainty such as water level, lockage time, and lock failure. Using this simulation tool, a series of lock repair and preventive maintenance actions are determined via Deep Reinforcement Learning (DRL) to minimize the loss due to lock-induced disruptions. To illustrate the proposed modeling and decision-making method, the McClellan-Kerr Arkansas River Navigation System is considered in our case study, where a random policy and a first-come, first-served policy conventionally implemented in practice are also presented for comparison. The results show that the optimal strategy obtained by the proposed DRL-based approach outperforms the conventionally implemented alternatives in various aspects. Most importantly, the levels of availability of all the locks are significantly improved, enabling a more seamless cargo flow along these navigable inland waterways. For the benefit of stakeholders, our further study reveals that employing multiple full-time repair crews instead of one can further increase the availability of the locks, but the idle time of these maintenance crews becomes more significant. This provides a way of thinking about the recruitment, deployment, and utilization of maintenance crews responsible for the smooth operation of such critical infrastructures
The Kids Aren’t Alright
No full textIt is not new that students struggle in law school. Research has shown for decades that, while students generally begin law school with healthy well-being, the competitive nature of law school combined with the stress of the Bar and securing post-Bar employment causes increased anxiety, depression, isolation, and related symptoms among students, especially women and underrepresented groups. What is new is the sheer number of law students struggling with serious mental health challenges today—a number that has reached crisis proportions.
This Article is divided into four parts. In Part I, I explore the mental health landscape for high school, college, and law students as well as practicing attorneys. In Part II, I explore some notable takeaways from the mental health literature, including that more women and underrepresented groups are suffering, and few students are seeking treatment In Part III, I explore research on Gen Z. Finally, in Part IV, I explore research on why law school causes elevated mental health symptoms among students and propose steps law schools and professors can take to improve students’ well-being
Conservatorship: An Enabler of Involuntary Servitude
No full textWhat happens when the conflict of interest relates to the conservatee’s substantial talents and their potential earnings? In this circumstance, a conservator has a perverse incentive to profit off of and coerce their conservatee into labor which serves to benefit the conservator—a kind of involuntary servitude that would seem to implicate the plain text of the Thirteenth Amendment of the United States Constitution.
This Note proceeds in three parts. Part I describes the history of conservatorships, why they were created, and the problematic issues that have arisen from the conservatorship system. Part IIanalyzes how the lack of meaningful judicial oversight creates the harmful potential for dynamics that arguably implicate the Thirteenth Amendment’s prohibition on involuntary servitude. Finally, Part III suggests a step forward to addressing the problem: a Guardianship Bill of Rights
Rice Cultivar \u27Ozark\u27
No full textA rice cultivar designated ‘Ozark’ is disclosed herein. The present invention provides seeds, plants, and plant parts derived from rice cultivar Ozark. Further, it provides methods for producing a rice plant by crossing Ozark with itself or another rice variety. The invention also encompasses any rice seeds, plants, and plant parts produced by the methods disclosed herein, including those in which additional traits have been transferred into Ozark through the introduction of a transgene or by breeding Ozark with another rice cultivar
