17007 research outputs found
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α -Tocopherol/sorbitol polyglycidyl ether loaded with Magnesium hydroxide composite particles with antimicrobial properties
No full textIn recent years, researchers have been exploring novel composite particles with antimicrobial properties for pharmaceutical applications. In this study, we loaded alpha-tocopherol, also known as vitamin E (1, 2, and 4 g) and sorbitol polyglycidyl ether mixtures onto magnesium hydroxide and evaluated their color coordinate values, cytotoxicity, and antimicrobial properties. The chemical structure of the composite particles was confirmed through Fourier-transform infrared spectroscopy (FTIR). Additionally, we measured the UV-Vis spectra of magnesium chloride (MgCl2), vitamin E, and sorbitol polyglycidyl ether as precursors for the vitamin E and sorbitol polyglycidyl ether-loaded magnesium hydroxide composite particles. Vitamin E showed the maximum absorbance peak below 350 nm, indicating potential UV protection properties. Color-spectrophotometer test was conducted on samples containing 1 and 2 g of vitamin E. The results showed that the L* values for the composite particles with 1 and 2 g of vitamin E were 97.5 and 96.6, respectively. The a* values for the samples containing 1 and 2 g of vitamin E were- 1 and -0.1, respectively. Therefore, no significant color difference was observed in the powders. The antimicrobial activity of the composite particle containing 4 g of vitamin E was tested against Staphylococcus aureus and Escherichia coli, with inhibition zones of 12.33 mm and 19.67 mm, respectively. We found no statistically significant change in A549 cell response to any of these compounds within the tested range, as determined by the MTT assay. However, there were some morphological and cell density changes when exposed to vitamin E, sorbitol polyglycidyl ether, and magnesium hydroxide. Specifically, the nuclear-to-cytoplasmic ratio increased (cell volume decreased), and cytoplasmic rounding with membrane irregularities occurred. The effect was least pronounced for magnesium hydroxide particles, but there was evidence of dose-dependent changes in the composites
The Iron Vanadate Composite as a High-Capacity Cathode for Aqueous Zinc-lon Batteries.
No full textAqueous zinc ion batteries are considered an alternative technology for lithium-ion batteries owing to their high safety and low cost. However, finding suitable cathode material (matching with zinc anode) remains a great challenge. Herein, we prepared an iron vanadate-based composite using the solvothermal method associated with further calcination at 500 °C. The as-prepared composite sample is used as a high-capacity cathode for aqueous ZIBs. The measured XRD results confirmed the formation of the FeV2O4/V205 composite phase. The oxidation and reduction peaks in the measured CV results confirmed that Zn+2 entered host cathode in multiple stages. The FeV2O4/V205 composite cathode delivered a high initial charge and discharge capacity of 312 mAh/g and 413 mAh/g at a current density of 500 mAh/g with an initial Coulombic efficiency of 75%, After 150 cycles, the FeV2O4/V205 composite cathode showed an excellent discharge capacity of 170 mA h/g. This work provides a new strategy for the preparation of vanadate-based composites for energy storage applications
Development of Bio-Based Polyurethane Adhesives: Impact of Schiff Base Crosslinkers on Mechanical and Thermal Properties
No full textHistorically, polyurethanes (PUs) are usually produced with petroleum-derived polyols like urea or phenol formaldehyde, both of which are hazardous to human health and detrimental to the ecosystem. Consequently, industries have lately shown interest in creating bio-based PUs composed of polyol derived from vegetable oil and diisocyanate. In this research, PU-based adhesives are created utilizing soybean oil polyol (SOP) and methylene diphenyl diisocyanate. To enhance the performance of synthesized PU adhesive, Schiff-based diols referred to as VB and VH have been incorporated into the system as crosslinkers, originating from butane diamine, hexane diamine, and vanillin. The successful production of PU has been validated with Fourier transform infrared spectroscopy (FT-IR) spectra. The tensile strength of adhesive samples was evaluated on oak wood specimens. In adhesive samples based on VB, VB-10wt.% exhibited the greatest tensile strength at 4400 KPa compared to all other weight percentages (wt.%), while for VH-based adhesive samples, the maximum tensile strength was recorded for VH-10wt.% at 5000 KPa. In both instances, as the wt.% of Schiff base diol rises, the tensile strength declines to 3800 KPa and 2900 KPa for VB-15wt.% and VH-15wt.% respectively. Additionally, the synthesized PU adhesive samples exhibit thermal stability, as verified by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) assessments. Furthermore, the gel content and degree of swelling tests additionally demonstrate the crosslinking efficiency of the PU adhesive materials
Trade-offs Between Limonene & Geraniol-Based Reprocessable and Non-Reprocessable Epoxy Thermosets: Role of Aliphatic Diamines in Polymer Networks Design.
No full textThe growing demand for sustainable materials, driven by environmental concerns and the rapid depletion of fossil fuels, has garnered significant attention in bio-based thermosets fabrication. Petroleum-derived thermosetting polymers can be replaced with renewable alternatives such as limonene and geraniol-derived epoxy prepolymers. The present study focuses on the synthesis and characterization of limonene and geraniol-based epoxy prepolymers over a two-step process and their thermally crosslinked thermosets using different aliphatic diamines. Incorporating cystamine, a disulfide-containing diamine, introduced a covalent adaptable network via disulfide metathesis, achieving a reprocessable thermoset with self-healing capabilities, recyclability, and extended lifespan. In contrast, traditional aliphatic diamines produced a permanently crosslinked thermoset with superior mechanical strength, thermal stability, and chemical resistance, ideal for high-performance applications requiring durability with maximum tensile strength of 11.62 MPa and 17.9 MPa for limonene and geraniol derived epoxy thermoset, respectively. Differential scanning calorimetry (DSC) elucidated the curing kinetics and crosslinking behavior, while thermogravimetric analysis (TGA) confirmed excellent thermal stability. Dynamic mechanical analysis (DMA) and tensile testing also demonstrated desirable mechanical properties. The glass transition temperature (Tg) of the limonene- and geraniol-derived malleable thermosets was determined by dynamic mechanical analysis (DMA) at 18C and 25℃, respectively. Above these temperatures, the malleable thermosets exhibited dynamic behavior facilitated by disulfide bond exchange. In addition, the developed materials displayed maximum tensile strengths of 3.1 MPa and 3.66 MPa, highlighting their mechanical robustness and potential for reprocessable applications
Effect of Unilateral and Bilateral Resistance Training on Performance Tests of Collegiate Softball Athletes
No full textStrength and conditioning coaches typically have athletes perform either unilateral (UL) and bilateral (BL) lower body training, based on the perception that UL may be more sport-specific, and may enable lighter loads due to different stability requirements. A randomized controlled design was used to assess the effects of UL (n=6) and BL (n=5) on collegiate DII softball athletes. After three weeks of familiarization training, testing was done pre- and post-8 weeks of the athletes\u27 Fall offseason training program. Performance testing consisted of strength (front squat, hex bar deadlift, front rack split squat, rear foot elevated split squat), change of direction (5-0-5 and 5-10-5), jump testing (vertical and horizontal), balance (modified Star Excursion Balance Test), softball-specific sprints (1st and 2nd - base), body composition (Bioimpedance analysis and Ultrasound), and rating of perceived exertion. A two-way ANOVA was run to determine differences between (group; BL vs. UL) and within (time; pre vs. post) on all variables. There were no significant interactions or group effects on any testing variable other than average weekly training volume (UL 63.6% less than BL). Strength tests, vertical jump and body composition increased similarly over time for both groups. Balance increased for UL only, but an ANCOVA demonstrated no significant group differences after controlling for different baseline values. Based on these results, both types of training may be equally effective, demonstrating a transfer of training effect regardless of modality. In addition, UL training may enable a reduced training volume which may be beneficial to athletes
Comparing inhibitory control across fishes
No full textThe ability to suppress predispositions in favor of more appropriate actions, also known as inhibitory control, helps organisms cope with fluctuating environments and is considered a central component of executive functioning. A common test of inhibitory control in animals is the cylinder task, in which a subject must detour a transparent cylinder to reach a food reward through side openings, instead of directly reaching for it and bumping into the front of the cylinder (which is regarded as an inhibitory failure). Here, we tested parrotfish-an understudied group of marine herbivores that inhabit coral reefs and seagrass-in a standardized version of the task. As a group, parrotfish performed poorly, failing to retrieve the food without touching the cylinder first in most trials (94%; two-tailed binomial test, N = 9, P \u3c 0.001). We compared our results with those of Lamarck\u27s angelfish-an omnivorous coral reef fish previously tested in the same procedure. We found that parrotfish showed a tendency towards failing more often than angelfish (two-tailed Fisher\u27s exact test, P = 0.075). When examining whether success or failure in the task was associated with decision making, however, we found that parrotfish were more likely to make a choice in the task, regardless of the outcome (two-tailed Fisher\u27s exact test, 90% vs. 70%; P = 0.002). We discuss the implications of these findings for our understanding of fish inhibitory control and, more broadly, the field of fish comparative cognition
Refining Recruitment Strategies at Pittsburg State University: Prioritizing Quality Engagement Over Quantity.
No full textEvery year thousands of prospective students visit Pittsburg State University and interact with its staff. This study aims to explore how the university can redefine its recruitment strategies to prioritize quality engagement over quantity. Specifically, I will examine how personalized follow-ups and meaningful interactions can enhance prospective students\u27 experiences, ultimately positioning PSU as a top destination for higher education in the region. This project will focus on the university\u27s technology department as a case study with a goal of developing a model that can be mirrored across all university departments seeking more effective engagement with prospective students. This analysis will assess current recruitment strategies, identifying potential gaps where interactions may lack depth or fail to leave a lasting impact. It will also explore how factors like mentorship opportunities, campus visit personalization, and alumni involvement could strengthen connections with prospective students. This research will use a series of different research methods focusing on quantitative data and a series of surveys gathering information from Pittsburg State University staff. By prioritizing quality over quantity in recruitment efforts, Pittsburg State University has the potential to attract and retain more students through intentional, high- value interactions that foster stronger connections between the institution and prospective students
Empathy in Action: Shaping Pizza PittStop Through User Insights
No full textThis study examines the user-centered design process behind our Pizza Pittstop, a conceptual food delivery application, with a focus of speed, reducing wait times, convenience, and user satisfaction. The research employs a multi-phase method: conducting in-depth user interviews, synthesizing findings into an empathy map, and developing a user persona that encapsulates core motivations and pain points. Building off user insights we empathize with them to create a user story and journey maps to articulate potential challenges and opportunities for improvement. Problem statements are defined to guide hypothesis formation, followed by a clear value proposition and goal statement. The investigation also encompasses a competitive audit and report, benchmarking Pizza PittStop\u27s proposed features against established industry standards. Additionally, design solutions are conceptualized through sketches, user flows, and a wireframe prototype developed in Figma. The project seeks to illustrate how the integration of user research and iterative design methodologies can result in more accessible, enjoyable, and reliable meal ordering experiences. This research emphasizes the significance of empathetic engagement and evidence-based decision-making in the development of a platform that effectively meets both the functional and emotional needs of users within the framework of contemporary dining practices
Boosting Li-S Battery Performance by Regulating Microstructures of Porous Hollow Carbon Nanospheres from Lignites
No full textLi-S batteries with high energy density are considered to be some of the most promising energy storage devices. However, the shuttle effect, sluggish kinetics, and volume expansion problems of lithium polysulfides (LiPSs) have severely limited their industrial applications. In this work, porous hollow carbon nanospheres (HCNSs) with tunable microstructures were designed by replacing resorcinol with an ethanol-soluble portion (ESP) from lignites rich in heteroatoms and alkyl side chains and employed as cathodes for Li-S batteries. The results show that the specific surface area, defect, and heteroatoms significantly increase after introducing ESP, thus promoting the adsorption and conversion of LiPSs. S@HCNS-30 exhibits the best electrochemical performance with a high initial discharge specific capacity of 1253.2 and 782.7 mAh/g at 0.1C and 2C, respectively, and a low decay rate of 0.075% per cycle after 500 cycles, which is much superior to S@HCNS from pure resorcinol and many other coal- or biomass-derived carbon materials. In addition, a high discharge-specific capacity of 659.9 mAh/g was achieved under challenging conditions of a depleted electrolyte (E/S = 10 uL-mg-1) and high areal density (5.3 mg/cm2 ). This work not only contributes to the high-value utilization of lignites but also provides a facile approach for high-performance cathodes for Li-S batteries
Structural transformation and electrochemical study of layered MnO2 in rechargeable aqueous zinc-ion battery
No full textLayered MnO2 is a very attractive cathode material for zinc-ion batteries (ZIB) due to its large interlayer distance, high discharge capacity, low cost, and environmental benignity. However, layered MnO2 exhibits capacity fading. Therefore, detailed studies of the structural transformation and electrochemical mechanism of layered MnO2 during cycling are urgently required for performance improvement. In this contribution, we have utilized in situ synchrotron, ex-situ X-ray diffraction, and ex-situ synchrotron X-ray absorption spectroscopy analyses to evaluate the structural transformation of a layered MnO2 during Zn-ion insertion. We found that during initial cycles, the electrode was able to maintain its layered structure; however, after prolonged cycles, it completely transformed into an irreversible spinel structure. We also observed the manganese dissolution from the electrode into the electrolyte during continuous cycling. The formation of the irreversible spinel phase and manganese dissolution are responsible for capacity fading. Our findings provide an understanding for further improvement of layered MnO2 as cathode material for next-generation ZIB systems