Toxicity and Effects of Tire Crumb Rubber in the Aquatic Environment

Plastic materials have provided innovative solutions to society’s evolving needs and challenges. Due to their durability and resistance to degradation, plastics remain in the environment for long periods of time and can therefore be transported to many environmental compartments such as water, sediment, and biota. Microplastics (MPs) have been defined as synthetic plastic particles that have at least one dimension less than 5 mm and are insoluble in water. Microrubber (MR), a recently acknowledged sub-group of MPs, has been documented in environmental samples more recently, frequently comprising a large portion of total MPs of various samples. In South Carolina specifically, suspected tire wear particles (TWP) have been found abundantly in sediment and water in the Charleston Harbor area, potentially originating from road runoff near major highways and bridges. Recent studies on MR have demonstrated toxicity in a variety of organisms, but with mixed results due to the complexity of the composition of MR and differences in test conditions. The goal of this research was to determine the toxicological impact of MR particles on aquatic organisms. To achieve this goal, the first objective addressed acute toxicity from exposure to MR particles and measured bile fluorescence as a biomarker for polycyclic aromatic hydrocarbon (PAH) absorption, metabolism, and biliary excretion, ethoxyresorufin-O-deethylase (EROD) activity as an indicator for cytochrome P450-1A (CYP1A) activity, and glutathione S-transferase (GST) activity as an indicator for oxidative stress. The second objective investigated toxicity under environmentally relevant conditions through a pulsed, chronic exposure. Immunohistochemistry (IHC) was utilized to visualize CYP1A induction in various tissues in addition to biomarker analyses for DNA damage, membrane damage, and oxidative stress. Finally, the third objective was to understand the environmental impact and fate of MR by analyzing MP abundance in biota collected from stormwater ponds. The results from acute toxicity tests revealed that bile fluorescence increased and CYP1A activity is induced as MR concentration increased, suggesting that PAHs are leaching from MR particles in the aquatic environment. Two fish species were utilized in acute exposures, the estuarine fish Fundulus heteroclitus (mummichog) and freshwater fish, Pimephales promelas (fathead minnow). Partial mortality was observed in P. promelas suggesting potential greater toxicity in freshwater conditions compared to estuarine or marine environments. Chronic toxicity tests were the first to our knowledge that utilized whole MR particles in exposures at environmentally relevant concentrations (\u3c 0.2 g/L) in fish. Immunohistochemistry of F. heteroclitus gill, intestine, and liver indicated strong induction of CYP1A in gill and liver cells and vasculature, with mild induction in intestinal cells and suggests that aqueous exposure to MR and thus MR leachate exerted a more prominent response compared to ingestion of particles themselves. Additionally, bile fluorescence increased as MR concentration increased as observed in acute exposures. Other biomarker tests indicated that antioxidant defenses were upregulated to prevent cellular damage as measured through an increase in the DNA damage byproduct 8-hydroxy-2’-deoxyguanosine (8-OHdG), a decrease in malondialdehyde (MDA) production indicating less lipid peroxidation, and an increase in the antioxidant, glutathione (GSH) when MR concentration increased. Finally, the abundance of MP and MR in field-collected organisms from coastal stormwater ponds was measured by visual microscopy of digested animals. Stormwater ponds are hot spots for environmental pollution, including MR from road runoff. The majority (\u3e80%) of MP recovered from biota across all sampling sites were suspected tire particles. The average number of MP per individual ranged from 0.3 to 71 MP and the average number of suspected tire particles per individual ranged from 0 to 57.7 tire particles. There were significant differences observed in the number of MP per individual between sites and between species. A combination of factors such as availability of MPs based on surrounding land use, stormwater pond dynamics, organism size, and organism feeding habitat influenced the total MP observed. Overall, these data indicate that MR particles and their associated compounds exert a toxic effect on aquatic species and that stormwater ponds serve as a sink for MR accumulation in the environment

A Cost-Effectiveness Analysis Of Individual Learning Units In A Junior High School Basic Mathematics Program.

The study was designed to: (1) determine the expenditures for an individual basic mathematics program in the junior high schools using individual Learning Units, (2) determine the expenditures for a traditional, textbook-oriented approach to basic mathematics instruction, and (3) compare the achievement gains of the two programs. Null hypotheses related to cost-effectiveness stated that the operational cost per unit gain, and the sum of the developmental and operational cost per unit gain of the ILU program would be greater than the cost per unit gain of the traditional approach. Null hypotheses related to effectiveness stated that the ILU treatment would not have a statistically significant effect upon: (1) total mathematics scores, ( 2) arithmetical computations, ( 3) arithmetical concepts, and ( 4) arithmetical applications

LIBRARY-FACULTY-VENDOR PARTNERSHIP TO CREATE STEM DIGITAL LEARNING ACTIVITIES

Olin College of Engineering’s Library staff set a 2013 academic year goal to transform their instructional program. Grounded in ACRL standards and ABET accreditation criteria, the program would become workshop-based, combining classroom experiences with digital exercises and tools. Library Director Magnoni began work with a materials science faculty member to design a research rubric for the digital exercise. Following a brainstorming session, a broad outline was created. Magnoni turned the outline into a diagram, and then created the initial exercise as well as a set of research tips for use with the course subject guide. Both the faculty member and Magnoni would collect electronic copies of the exercise. Students would also keep copies for their own reference. To facilitate this sharing, a simple Microsoft Word document was created. The document included page breaks between research elements, and students could document their process, save as they moved through pieces, and then both keep and send copies. The research tips were saved in a PDF document and a course subject guide already existed on the LibGuides platform. These three pieces: an exercise in Microsoft Word format, research tips in PDF format, and a subject guide delivered on the LibGuides platform, made up the test elements. Two rounds of testing were accomplished in the experiment’s first week, with modifications made for different course offerings. In addition to faculty and student feedback, Magnoni realized shortcomings of the three different formats for delivery. Through a conversation with Ricords of Credo, a Literati subscription facilitated the creation of engaging and interactive multimedia learning materials. This paper will discuss the conception and development of the research rubric, online portal and interactive tutorials, along with assessment and accreditation potential. The feedback and iteration process will be explored, and the value of the library-faculty-vendor partnership highlighted

Toxicological effects of tire wear particles on mummichogs and fathead minnows

Recent studies on the distribution of microplastics in the Charleston Harbor, SC, revealed that a large part of the microplastic particles that are found in the intertidal sediments are tire wear particles. These particles originate from the wear of tire treads on roadways, and wash into the estuary during rain events. The abundance of these particles has raised questions about potential toxicity to aquatic organisms that may ingest these particles. The synthetic rubber in car tires consist of a large variety of chemicals, which can vary between brands, but usually contains styrene-butadiene rubber, carbon black and zinc. To investigate the potential toxicity of tire wear particles, both fathead minnow and Atlantic killifish were exposed to different concentrations of tire crumb particles (38 – 355 µm) in a 7-day exposure. Dissection of the fish revealed that particles were ingested and accumulated in the intestinal tract. At the highest concentration tested (6000 mg/l) we observed partial mortality in the fathead minnow, which is therefore close to the LC50. To investigate if polynuclear aromatic hydrocarbons were leaching from the particles, bile fluorescence was measured, together with potential induction of cytochrome P450-1A through the EROD assay. Elevated levels of 2-, 4-, and 5-, ring structures resembling polynuclear aromatic hydrocarbons were detected in the bile of exposed animals. Induction of CYP1A was also observed in exposed animals at environmentally relevant concentrations (\u3c1-2 g/l)

Gene expression patterns following unilateral traumatic brain injury reveals a local pro-inflammatory and remote anti-inflammatory response.

BackgroundTraumatic brain injury (TBI) results in irreversible damage at the site of impact and initiates cellular and molecular processes that lead to secondary neural injury in the surrounding tissue. We used microarray analysis to determine which genes, pathways and networks were significantly altered using a rat model of TBI. Adult rats received a unilateral controlled cortical impact (CCI) and were sacrificed 24 h post-injury. The ipsilateral hemi-brain tissue at the site of the injury, the corresponding contralateral hemi-brain tissue, and naïve (control) brain tissue were used for microarray analysis. Ingenuity Pathway Analysis (IPA) software was used to identify molecular pathways and networks that were associated with the altered gene expression in brain tissues following TBI.ResultsInspection of the top fifteen biological functions in IPA associated with TBI in the ipsilateral tissues revealed that all had an inflammatory component. IPA analysis also indicated that inflammatory genes were altered on the contralateral side, but many of the genes were inversely expressed compared to the ipsilateral side. The contralateral gene expression pattern suggests a remote anti-inflammatory molecular response. We created a network of the inversely expressed common (i.e., same gene changed on both sides of the brain) inflammatory response (IR) genes and those IR genes included in pathways and networks identified by IPA that changed on only one side. We ranked the genes by the number of direct connections each had in the network, creating a gene interaction hierarchy (GIH). Two well characterized signaling pathways, toll-like receptor/NF-kappaB signaling and JAK/STAT signaling, were prominent in our GIH.ConclusionsBioinformatic analysis of microarray data following TBI identified key molecular pathways and networks associated with neural injury following TBI. The GIH created here provides a starting point for investigating therapeutic targets in a ranked order that is somewhat different than what has been presented previously. In addition to being a vehicle for identifying potential targets for post-TBI therapeutic strategies, our findings can also provide a context for evaluating the potential of therapeutic agents currently in development

Assessing brand personality associations of top of mind wine brands

Purpose – The purpose of this paper is to examine brand knowledge of wines produced in a selected Portuguese viticulture area. More specifically, we intend to understand how consumers organise brands that have the highest awareness in their memory in terms of perceived personality traits. Design/methodology/approach – A survey was developed to assess brand awareness of Portuguese green wine brands and brand personality using Aaker’s brand personality framework. Multiple correspondence analysis was used in this study to present the relative positioning of the top-of-mind green wine brands. Findings – Despite the large number of green wine brands available on the market, six brands dominate in terms of brand awareness. Top-of-mind green wine brands are marked with clear and distinctive brand personality, and a small subset of brand personality attributes serve as significant criteria for brand positioning. Practical implications – The results of the present study could be beneficial for academics and practitioners, as it reveals that the top-of-mind brands within a specific viticulture area could exhibit a clear positioning based on personality traits. Therefore, brand personality traits might provide a mechanism for wine managers to distinguish or differentiate their wines. Originality/value – This work contributes to the findings of previous studies held to study brand personality perceptions. From a theoretical point of view, this paper reflects the usage of one the most popular instruments for brand personality measurement in a wine market context.info:eu-repo/semantics/submittedVersio