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CRYSTALLIZATION OF NANOCERIA WITHIN A BORATE GLASSES
No full textA soluble borate glass doped with different concentrations of cerium (IV) oxide was used to create multivalent CeO2(Ce4+) and Ce2O3(Ce3+) nanoparticles. The glass is melted with varying cerium (IV) oxide and under different melting conditions to achieve varying quantities of Ce3+ and Ce4+ nanoparticles. Differential Thermal Analysis (DTA), Transmission Electron Microscopy (TEM), and Raman Spectroscopy were conducted to investigate the crystal growth of CeO2 and Ce2O3 nanocrystals and their structure. We have identified several crystal structures and the study shows crystal formation changes with the ratio of Ce3+/Ce4+ nanoparticles
Eristalis tenax Movement Behavior in Response to Light, Temperature, and Food
Get PDFDrone flies, Eristalis tenax (Diptera: Syrphidae), are important generalist pollinators and visit flowers globally that range widely in color. The flies’ photoreceptors allow them to sense light wavelengths between 300-600 nm and E. tenax exhibit a positive phototactic response. To understand the effects of light on E. tenax movement, we conducted two-choice behavioral tests to determine their phototactic response to different wavelengths of light across the spectrum (ultraviolet to red light, plus full spectrum white light). The drone flies moved most and quickest toward sunlight, with almost twice the percentage of flies moving toward sunlight than toward black and purple light (short wavelength sources), which elicited the second strongest phototactic responses. Eristalis tenax moved minimally toward green and red light sources. When increasing air temperature by 6°C, the percent of E. tenax moving toward fluorescent white light increased by a factor of four. They also moved toward a food source in light but not dark conditions. Our findings may be useful for managing E. tenax populations in the lab or for increasing crop pollination
INVESTIGATING THE CYTOTOXICITY OF BACTERIOPHAGE CEPENS GENES IN HOST MYCOBACTERIUM SMEGMATIS**
No full textBacteriophage are viruses that infect prokaryotes. Although they have a vast population, their genetics and regulation are largely unknown. For example, most phage currently sequenced have functions predicted for approximately one third of their genes. A fascinating place to begin with is knowing which genes specifically kill their bacterial hosts, or are cytotoxic. Knowing the cytotoxicity of each phage gene individually would give us a better understanding of phage genomes, and phage-host interactions. Four genes (gp1, gp3, gp4, and gp37) from a phage named Cepens, will be amplified using Polymerase Chain Reaction (PCR) and cloned into a plasmid (pExTra) with isothermal assembly. This cloned plasmid will then be chemically transformed into E. coli and transformants verified through Colony PCR and selective Kanamycin plates. These bacteria can mass produce the plasmid and allow it to be extracted using a mini-kit for future molecular usage. Using electroporation, the cloned plasmid with the gene of interest will be introduced into a known bacterial host for Cepens, Mycobacterium smegmatis mc2155. Cytotoxicity assays will be performed using the inducer anhydro-tetracycline (aTc) and measured with bacterial growth where decreased growth indicates cytotoxicity of that individual gene. Genes 1, 3, and 4 have annotated functions as a helix-turn-helix DNA binding protein, Helix-turn-helix domain protein, and unknown respectively. We would expect genes 1 and 3 to not be cytotoxic as these functional predictions indicate roles in gene regulation, while 4 is unknown. Gene 37 has an annotated function of a putative Holin protein. We expect to see this as a cytotoxic gene given it is well characterized in the literature to be responsible for interfering with membrane stability and causing cell lysis. Knowledge of cytotoxicity of individual phage genes could have implications in therapeutics for development as potential drugs that can kill bacteria independently of phage infection limitations
ANTIMICROBIAL PROPERTIES OF STEVIA REBAUDIANA BERTONI, 1899
No full textStevia rebaudiana is a plant grown primarily in South America and goes by such names as sweet grass, honey-leaf, sweet herb or sweet-leaf. The leaves contain steviol glycosides, which contribute to sweetness. Today, several non-caloric sweetener Stevia products are widely available for purchase. Steviol glycosides have proven antimicrobial properties pertaining to microbes specifically residing within biofilms in the human oral cavity. In addition, its anticancer and antifungal properties have also been investigated. Specifically, compound Rebausdioside A is a steviol glycoside that expresses antimicrobial properties. The purpose of this study was to test Rebaudioside A in an organic mixture of natural Stevia extract for its effectiveness at neutralizing Streptococcus mutans and Lactobacillus acidophilus. These microbes are known for causing dental caries in humans. Freeze-dried pellets were rehydrated in tomato juice for L. acidophilus and in Brain Heart Infusion (BHI) broth for S. mutans. After successful inoculation on Tryptic Soy Agar (TSA) with 5% sheep blood plates, S. mutans were inoculated on BHI agar plates and tested against Aqueous 99% Rebaudioside A, 70% Ethyl Alcohol with 99% Rebaudioside A Extract, and 4% Chlorhexidine Gluconate (standard control for susceptibility determination) using a well-plate method. The alcohol extracts were synthesized by adding solid extract into liquid alcohol and filtered using muslin cloth and Whatman No. 1 filter paper. After evaporation, alcohol extracts were diluted with DI water to 50% concentration. On the other hand, L. acidophilus did not rehydrate successfully and was replaced with a Human Saliva swab. Results from three trials showed that 4% Chlorhexidine Gluconate performed as expected with a mean zone of inhibition for S. mutans at 23.75mm and for Human Saliva at 32.25mm. Organic aqueous Stevia extract did not show the same effectiveness even when combined with 70% Ethyl Alcohol. A possible explanation could be that S. mutans converted the alcohol into acetaldehyde as it possesses alcohol dehydrogenase. In addition, other studies have shown that ethanol is not able to penetrate the gram-positive cell wall of S. mutans. Aqueous Stevia extract showed zones of inhibition ranging from 9-11mm for the Human Saliva inoculates but for Stevia in combination with 70% Ethyl Alcohol, again no bacterial growth was inhibited
THE EFFECT OF ENVIRONMENTAL CONDITIONS ON GORDONIA TERRAE -SPECIFIC BACTERIOPHAGE DISTRIBUTION AND DIVERSITY**
No full textBacteriophages are viruses that infect a diverse range of bacteria, with certain strains serving medical and industrial significance. These highly specific infectious agents are extremely abundant and genetically diverse, representing a vast reservoir of unexplored genetic information. Additionally, phage therapy – the use of phage to treat bacterial infections – is of medical significance due to the ongoing fight against antibiotic resistance. Actinobacteriophages are viruses that specifically infect Phylum Actinobacteria hosts including the environmentally abundant Gordonia terrae. Some species of Gordonia, including G. terrae, have also been isolated from human infections. The isolation and characterization of novel phages that can infect Gordonia can therefore be significant to both genomics and potential phage therapy. Actinobacteriophages that infect these bacteria have been isolated from soil environments, but optimal environmental parameters for isolation have not been fully evaluated. In this study, monthly soil samples were collected from different regions in central Georgia to isolate novel Gordonia phages and to determine if environmental conditions, including soil chemistry, affect phage distribution and diversity. Isolation success from different environments was determined by presence of phage in G. terrae enriched samples. Viable Gordonia phage was successfully isolated the Turner Creek Boat Ramp site in Savannah, GA. Preliminary data indicates that soil pH, organic carbon, and chlorine influence phage abundance. A soil pH range 7.0-7.9 appears most favorable for phage isolation. A positive correlation between soil organic carbon and phage abundance was also observed. Similarly, the isolation of the phage correlates with the presence of soil chlorine. To investigate the effect of these environmental conditions on their genetic diversity, phage successfully collected are undergoing genomic analysis to compare them to existing genomic clusters of Gordonia phage. This study would inform optimal soil conditions for Gordonia-specific phage isolation while providing valuable genetic data on virus diversity in central Georgia
EVALUATION OF THE EFFECT OF ELEVATED HYDROSTATIC PRESSURE FOR INACTIVATION OF LISTERIA MONOCYTOGENES.
No full textThe growth and survival of food borne pathogens in the food processing industries is one of the most important concerns affecting the health safety of consumers by causing infections and food spoilage. Listeria monocytogenes is recognized as a widespread foodborne pathogenic species that causes Listeriosis outbreaks associated with a variety of food products. There are only a limited number of studies available demonstrating the synergistic efficacy of combining different control mechanisms against food borne pathogens (such as L. monocytogenes), which could increase the food safety and the shelf life of food products. The current study investigated L. monocytogenes inactivation using high-pressure processing (HPP) only and a combination of HPP and caprylic acid. In this study we used a constant inoculum level 10^7 CFU/ml, exposed to different pressure intensities (200 - 500 MPa), with or without the addition of 0.1% caprylic acid, for 0, 3, and 5 minutes at 4℃. Exposure to 400 MPa at 4℃ without caprylic acid resulted in about a 2.0 log CFU/ml reduction in L. monocytogenes, while exposure to 500 MPa resulted in 3 log CFU/ml reduction. Exposure to 400 and 500 MPa at 4℃ with the addition of 0.1% caprylic acid did not show any significant differences in the log CFU/ml reduction compared to treatments without synergism. Treatments conducted at less than 400 MPa were less effective at the decontamination of L. monocytogenes. Generally, the longer the sample was exposed to elevated hydrostatic pressure, the more effective the decontamination effort was. This was more apparent at treatments of 400 MPa or greater. The results of this experiment could be important to the future of food decontamination protocols as it shows an effective alternative to the popular methods currently utilized in food safety management systems working to mitigate the burden of listeriosis
SPATIAL AND ABIOTIC EFFECTS OF URBANIZATION ON SMALL MAMMAL COMMUNITIES
No full textUrbanization is known to decrease the richness and abundance of native wildlife populations, fragment natural areas, and increase human and human-commensal animal interactions with wildlife. Dynamics of species persistence in habitat fragments is often understood in the framework of island biogeography theory (IBT), with habitat fragments being analogous to oceanic islands. However, urban environments present different challenges to dispersal and persistence than literal oceanic islands, so the applicability of IBT to urban ecology is unclear. We investigated how small mammal communities respond to spatial and environmental factors associated with urbanization. These communities are important to consider in urban fragments because of their roles as prey animals, seed dispersers, and their potential to transmit viruses and parasites to humans and human-commensal animals. We trapped small mammals at 23 sites along an urban-to-rural gradient centered in Atlanta, Georgia, USA from May-August 2023. Sites were characterized by in situ environmental conditions such as temperature, ambient light, vegetation, and sound; additionally, we obtained landscape-level data on human population, land use, and socioeconomic variables from public databases. We integrated these data using geographic information systems (GIS) and modeled species richness and other community metrics using generalized linear models. Our preliminary conclusions are that small mammal communities differ between urban, suburban, and rural locations; that these differences are driven by the presence or absence of a small number of species; and that land cover surrounding sites had little impact on small mammal community structure. Further analyses will investigate how spatial, environmental, and socioeconomic factors affect small mammals in urbanizing landscapes
CELLULAR AND MOLECULAR BASES OF TRAUMA-RELATED ROOT RESORPTION
No full textPermanent teeth rarely undergo root resorption since the cementum covering on dentin is an essential element in the resistance of the dental root to resorption. It has been documented that osteoclasts will not adhere to or resorb non-mineralized osseous tissues. However, once the bone matrix is mineralized due to repair following dental trauma, RANKL/RANK/OPG system activate osteoclasts leading to bone resorption. Root resorption, not detected by conventional radiography typically remains asymptomatic, compromises tooth structure and eventually causes tooth loss. This paper reviews the pathophysiology of root resorption and presents a case study in which the apex and circumferential resorption resulted in a root shortening that exceeded 56%. The paper suggests that the extent of root resorption depends on the magnitude of the destruction, the tissue types involved, and the resorption duration
DETECTION OF SOLAR SYSTEMS WITH LAPLACE RESONANCES USING HUBBLE SPACE TELESCOPE DATA**
No full textOrbital resonances occur when star or planetary systems with multiple planets or moons exhibit stable orbits that have simple ratios of frequencies in their orbits. One particularly regular example of this phenomenon is a Laplace resonance, which has a ratio of the orbital periods of 1:2:4. Analyzing the radial velocity of the central body as a function of time for a system with a Laplace resonance should produce visible and predictable oscillations that correlate to the orbital frequencies of the planets in the stars orbit. The goal of this project is to attempt to measure the radial velocity of a star in a Laplace resonance system using Doppler shifting, with the end goal of observing regular changes in velocity that correspond to the predicted periods, and then measuring any deviations which may indicate the presence of additional planets. The method is currently being developed using Hubble Space Telescope data from Gliese 876, a red dwarf located 15.2 light-years from our solar system which is known to have orbiting planets exhibiting a Laplace resonance
EVALUATION OF SPLIT-RING RESONATOR FABRICATED USING LASER CUTTING AND CNC METHODS **
No full textThe Split-Ring Resonator (SRR) is a fundamental component in the field of metamaterials and has been significantly developed in the past years. The typical structure is the split rings with specific gap. It has been used in different applications, such as communication, antenna design and sensing. In this on-going project, we focus on developing efficient and cost-effective methods for fabricating SRR devices. Our approaches involve utilizing accessible techniques, specifically laser cutting and computer numerical control (CNC) machining to create the SRR structures. Laser cutting techniques were used to generate the pattern onto a coated copper board, followed by removing the copper part and produce the SRR device. Meanwhile, CNC engraving was utilized to directly draft the SRR shape. It is demonstrated that both methods have successfully produced the desired devices. The laser cutting exhibited superior precision compared to the CNC methods since the minimum engraving dot diameter is about 0.2 mm, and the CNC resolution is limited by its drill size which is approximately 2 mm. CNC method showed the convenience in its applications since no extra coating and copper etching are required. Next the both fabrication methods are used to fabricate the SRR devices with the identical design parameters. The electromagnetic characteristics of the devices is evaluated with the network analyzer. The resonance frequencies are theoretically derived and compared to the experimental results. The project offers the feasibility of accessible fabrication techniques for SRRs, providing their respective advantages and limitations. Future development of these techniques is promising to enhance the efficiency and prevision of SRR device fabrication and applications