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ECOTOXICOLOGICAL EFFECTS OF LITHIUM CHLORIDE ON LYNGBYA WOLLEI**
No full textLyngbya wollei is a macroscopic benthic filamentous cyanobacterium that forms thick mats in freshwater lakes and ponds in the southeastern United States. Recently, it has become a nuisance species because it clogs water intakes, impedes freshwater navigation and recreation, smothers underwater plants, and emits paralytic shellfish toxins (PSTs). Lithium chloride is a good candidate for safe eradication of L. wollei in freshwater environments because it can be phycoremediated and phytoremediated at relatively high concentrations, is relatively nontoxic to plants, invertebrates, and aquatic vertebrates and it is not expected to bioaccumulate. In this experiment, microcosm cultures of L. wollei collected from Grassy Pond Recreation Area in Lake Park, GA were placed in 300 mL BOD bottles and treated with increasing concentrations of lithium chloride. To assess the impact of lithium chloride treatment on other freshwater aquatic species, the experiment was performed on microcosms dominated by filamentous desmids as well. Transects of random samples from each treatment group were used to obtain light micrographs to assess damage to cells via ImageJ . Damage was quantified as the proportion of unhealthy cells out of the total cells observed in the transects. Preliminary results indicate that treating cultures with 200 mg/L of lithium chloride (the maximum concentration that can be completely remediated from an aquatic system) inflicted significant damage to Lyngbya wollei filaments, while insignificantly impacting the filamentous desmids
QUANTUM THEORY OF CONTACT ELECTRIFICATION
No full textWe present a unified quantum-mechanical model of contact electrification that provides a microscopic basis for the Volta-Helmholtz-Montgomery hypothesis. Our model can represent metals, semiconductors and insulators, in either fluid or solid phase, and with an effective electron transfer mechanism. Standard experimental results such as the charging of similar materials, surface charge mosaic, and the higher efficiency of charge transfer for a liquid-solid contact, compared to a solid-solid one, are reproduced. A quantum-mechanical charge oscillation in the femtosecond to picosecond regime is predicted to take place. Coulomb interaction is found to have an impact on not just the charge transferred but also the period of charge oscillation
A NOVEL SCREENING METHOD FOR ORAL CANCER
No full textThe advancement of techniques used to screen for oral cancers has been negligible for decades. Despite the mouth being an easily accessible part of the body, testing for neoplasia in this area relies almost entirely on the visual acuity of one’s dental provider. Excluding knowledge of risk factors and genetic predispositions, screening for potential oral neoplasia occurs only when an abnormality can be seen with the naked human eye. To prevent the development of cancers such as squamous cell carcinoma, there must be a screen that allows providers to catch the issue before it has spread. The current standard is to visit a dentist and have a dye test or biopsy done. In this study, we have explored the concept of a testing method that any individual could complete at home, with chewing gum. Acknowledging that collagen has been shown to increase adherence rates within OSCC (oral squamous cell carcinoma) cell lines, we chose to mix a collagen additive into a gum base. We then tested the collagen-enriched gum against a control gum free of additives to determine whether the collagen would increase the screening potential for a specific p53 tumor suppressor gene mutation. Samples of both types of gum were disseminated amongst a small population including individuals with known oral squamous cell carcinoma. Upon collection of the samples, polymerase chain reaction was performed to determine whether a mutation in one of three exons would be diagnostic of potential oral cancer. After verifying that exon 8 held the greatest diagnostic potential, another experiment was run with a focus on that primer. Preliminary results indicate that the collagen-infused gum may create greater adherence amongst neoplastic cells
USING BIOFLAVONOIDS TO INHIBIT CYP1A1 INDUCTION BY COMPONENTS OF COOKED CHICKEN
No full textWhen in the presence of a ligand, the aryl hydrocarbon receptor (AHR) helps regulate metabolism of polycyclic aromatic hydrocarbons by inducing expression of the CYP1A1 enzyme. Examples of environmental exposures that contain these ligands include: cigarette smoke, burning rubber, and char on cooked food. One of the main AHR ligands in these is benzo[a]pyrene (B[a]P), a procarcinogen that becomes a DNA-damaging metabolite when activated by CYP1A1. Naturally occurring flavonoids and stilbenoids have been shown to inhibit CYP1A1 induction, preventing this dangerous metabolite formation. For this research, two samples of chicken were used, grilled and baked, to mimic practical daily consumption of these B[a]P deposits. Ethanol extracts created using the char from the grilled sample were able to activate expression (13-fold) in mouse hepatocytes, as determined by a CYP1A1-promoter luciferase reporter gene, but the baked samples were not. Further, pretreatment with any of the three flavonoids tested decreased this induction: 100nM hesperetin (49% decrease), 100nM quercetin (80% decrease), or 100nM apigenin (99% decrease). Pretreatment with the stilbenoid, resveratrol (200nM), was not able to inhibit CYP1A1 induction. These data suggest that baked chicken contains less CYP1A1-inducing compounds than grilled chicken and foods high in bioflavonoids (especially apigenin) could prevent the activation of B[a]P and, thus, reduce cancer risk
Middle Woodland Period Settlement Hierarchy in the Etowah River Valley**
No full textDuring the Middle Woodland Period (300 BC – AD 600), large burial mounds became religious centers in many areas along major rivers throughout Southeastern United States. This cultural period witnessed an advance of communication and trade to different areas of the East Coast. These centers provide information into how social networks and hierarchies worked in the form of goods traded along rivers and where people lived in proximity to these centers. The Leake Site, located in the Etowah River Valley in north Georgia, is regarded as a major ceremonial center, but is debated in terms of whether it served a singular role as an economic hub or a dual one in which it served both and economic and ceremonial (pilgrimage) one. Identifying the size and geographic location of archaeological sites surrounding Leake is used to determine whether there was any settlement hierarchy in the region, with Leake at the apex, during Middle Woodland times. Specific artifacts which were usually traded amongst higher ranked individuals such as Swift Creek pottery and its distribution to different sites surrounding Leake points to what the habitants did or how they were used in a social setting
COMBINING THE LIBERAL ARTS IN GENERAL BIOLOGY COURSES
No full textGeneral or introductory biology courses can be significantly enhanced by exploring course content from the perspectives of other liberal arts disciplines. Engaging with other subjects has the potential to broaden and deepen students’ understanding of general biology topics and to increase their understanding and appreciation of the relationships among different fields of study. Moreover, this multi-lens approach can help improve students’ capacities to read, write, and think critically and strengthen their awareness of the relevance of science to all aspects of life. Instructors in general biology courses can develop creative content and assignments that include ideas and viewpoints not only from the natural sciences but from the social sciences and the humanities as well. For example, environmental topics can be further explored through the lenses of history, literature, sociology, media, and other socio-humanistic areas, each discipline providing information and perceptions about environmental questions and concerns and all contributing to a richer understanding of environmental issues and the interconnectedness of academic subjects. History may be utilized to examine the origin and development of the environmental movement and to highlight significant environmental policies in the U.S. during the past century. Literary works that explore humans’ relationship to the natural world may be included, and students can be encouraged to create their own poems and stories about nature. Sociology and media can be employed to examine issues involving climate change, sustainability, and environmental justice. Combining liberal arts disciplines in general biology courses can facilitate the development of enhanced critical skills, a more comprehensive understanding of course topics, and a greater awareness of the relationship of biology to other academic subjects and to real-life concerns
Mechanical vibrations attenuation by granular media at audible frequencies for especial applications
No full textAbsorption of structural vibrations by granular media is investigated to prevent transmission of vibrations into the structures by surrounding the structure with granular media. Mechanical properties of media are selected for specific vibration absorption characteristics. Experimental results show that frequency band-gap of the media can be moved by design to fit the required frequency band, where scattering and dissipation of vibrational energy is maximum. Samples of granular media are subjected forced mechanical vibrations at different audible. The attenuation versus frequency are determined. Effects of thickness, particle size, and medium compactness, are investigated at different frequencies and intensity. The goal is to obtain granular media properties required for maximum vibration attenuation for especial applications of vibration free structures
THE EFFECTS OF LOW PH ON SEA URCHIN LARVAL SURVIVORSHIP AND DEVELOPMENT
No full textIn recent decades, increasing atmospheric CO2 levels have contributed to the acidification of the world’s oceans. Seawater absorbs CO2 from the atmosphere, which, through a series of chemical reactions, causes an increase in free hydrogen ions and a subsequent decrease in carbonate ions. This adversely affects marine organisms, including sea urchins, since carbonate is critical for building calcium carbonate structures such as shells, without which organisms can die. Declines in urchin populations can have ecological and economic effects, as urchins play critical roles in maintaining ecological balance in marine habitats and are important commercially harvested invertebrates. Larval marine organisms are particularly vulnerable, and increased deformities and mortality are expected in more acidic environments. Therefore, we exposed green sea urchin (Lytechinus variegatus) larvae to different pH levels and examined the effects on development and mortality. Fertilized eggs were reared in seawater with environmentally realistic pH values ranging from pH 7.8 to pH 8.2 (normal seawater), and a larval sample from each treatment was collected every 24 hours for 7 – 10 days. Mortality was documented by counting dead larvae, and development was assessed by comparing morphology among the control and treatment groups. In general, both mortality and morphological abnormalities showed inverse correlations with pH, with the highest mortality rate and most severe abnormalities occurring in larvae exposed to the lowest pH seawater. Larval development was also somewhat delayed in urchin larvae exposed to low pH seawater. These results suggest that acidic seawater, at pH values currently found in the world’s oceans, can adversely affect sea urchin larval development, which can, in turn, have negative ecological and economic consequences
UNDERSTANDING BIODIVERSITY THROUGH TAXONOMIC TRAINING
No full textAmphipods are important bioindicators that can be found in almost any body of water. The presence of amphipods can provide an abundance of information about the environment. However, amphipods are frequently misidentified, rendering most of the information gained from them unusable. This issue has highlighted a need for taxonomic training. The goals of this project include teaching students various methods used in amphipod taxonomy, such as collection, dissection, and identification of amphipods. Equally important is that students understand the role of amphipods in their environments. In addition to traditional morphological taxonomy techniques such as scientific illustration, students will learn to use a stacking imaging system to create more detailed photographs useful in identification. Proficiency in these types of skills benefits the fields of taxonomy, ecology, and conservation while providing a set of skills that students can use throughout their careers. Once trained, students will apply their skills to a project funded by the National Science Foundation which focuses on Caribbean amphipods of Panama. The project will ultimately result in a revisionary systematics monograph describing the regional amphipod diversity and identification tools for both experts and non-experts. The methods listed here will be described and potential applications of the project results by non-experts will be presented
DEVELOPING A METHOD TO QUALITATIVELY DESCRIBE HAUSTORIA OF NOTHOPASSALORA PERSONATA IN INFECTED PLANT TISSUE**
No full textNothopassalora personata causes late leaf spot disease in peanut (Arachis hypogaea), which results in premature defoliation and substantial yield loss. A common method of reducing late leaf spot disease is through the use of fungicides, however this can be quite expensive and is sometimes unavailable. Because of this, peanut cultivars are being bred for traits that demonstrate resistance to late leaf spot. Resistant cultivars in other pathosystems of fungi are able to combat infections by restricting intracellular haustoria. One way to observe these intracellular haustoria is with the use of a scanning electron microscope. In this study, two cultivars of peanut will be compared; one resistant and one susceptible. A detached leaf assay will be conducted to establish disease on peanut leaves and petioles. Sections will be taken from both the petiole and the leaf and will be prepared for scanning electron microscopy using standard methods. Scanning electron micrographs of intracellular haustoria will be processed using ImageJ to compute the percentage of cell area occupied with haustoria, to see if halting intracellular haustoria is a mechanism for resistance in peanuts. Results of this experiment will be presented