Matching Items (103)

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Black Widows on an Urban Heat Island: Understanding Physiological Responses to Global Change

Description

The steroid hormone 20-hydroxyecdysone (20E) controls molting in arthropods. The timing of 20E production, and subsequent developmental transitions, is regulated by a variety of factors including nutrition and photoperiod. Environmental

The steroid hormone 20-hydroxyecdysone (20E) controls molting in arthropods. The timing of 20E production, and subsequent developmental transitions, is regulated by a variety of factors including nutrition and photoperiod. Environmental factors, such as temperature, play a critical role in regulation as well. The increasing prevalence of urban heat islands (UHI), or areas with elevated temperature due to retained heat by built structures, in response to rapid urbanization has made it critical to understand how organisms respond to elevating global temperatures. Some arthropods, such as the Western black widow spider, Latrodectus hesperus, appear to thrive under UHI conditions, but the physiological mechanism underlying their success has not been explored. Recently, we have shown that L. hesperus, a troublesome urban pest, in fact responds to urban heat island conditions in Phoenix, AZ with delayed development, reduced body mass, and increased mortality. Here we look at the relationship between 20E levels and development in spiderlings reared under desert (27ᵒC), intermediate (30ᵒC), and urban (33ᵒC) temperatures, filling a noticeable gap in not only understanding ecdysteroids’ role in arachnid development but how incremental changes in environmental conditions affect the regulation of this process. Developmental progression and hemolymph 20E titers were recorded for several families of spiders collected from across the urban Phoenix area with data spanning from day 55 to 75 of development, focusing on the second developmental instar. We found that 33°C, but not 30°C, led to 1) a significantly higher production of 20E throughout development, 2) a reduced and delayed molt-inducing 20E peak, and 3) noticeable reductions in growth rate and mass. At 30°C, a variable response is seen in molt timing, without the negative impacts on size and mortality as seen at 33°C, suggesting that at UHI temperatures, the optimal developmental temperature threshold has been surpassed.

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Created

Date Created
  • 2019-05

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You Gotta Eat the Lettuce: An Examination of the Effects of Lutein and Zeaxanthin on Contrast Sensitivity

Description

Lutein and zeaxanthin are two important carotenoid vitamins related to ocular health and human visual processing. These vitamins can be ingested through supplementation and in regular diet. They concentrate in

Lutein and zeaxanthin are two important carotenoid vitamins related to ocular health and human visual processing. These vitamins can be ingested through supplementation and in regular diet. They concentrate in the central retina where they form a filter of macular pigment and protect the eye from high energy blue and yellow light. We examined participants who had a natural diet of high vs low lutein and zeaxanthin intake on tests of contrast sensitivity and glare disability. We also examined participant performance while wearing blue light blocking glasses in order to determine whether these glasses serve a similar protective function as macular pigment in benefiting participants on contrast sensitivity and glare disability tasks. Most of our data did not show statistically significant differences between the high and low lutein and zeaxanthin groups. An unexpected result that the blue blocker glasses hindered the ability of low lutein participants on their glare disability test was observed. We hypothesize that this is due to light scatter produced by the by glasses resulting in an impoverish retinal image reaching the primary visual cortex. Further research is required to examine this new finding.

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Created

Date Created
  • 2019-05

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Treatment for T-Cell Lymphoma Cancer: Synthesis of Analog Compound of Bexarotene

Description

Cancer, a disease which affects many lives, has been the topic of interest for this research. Treatment options are often available to help lessen the effects of the disease and

Cancer, a disease which affects many lives, has been the topic of interest for this research. Treatment options are often available to help lessen the effects of the disease and in regards to cutaneous T-cell lymphoma (CTCL), no cure currently exists. An FDA approved drug by the name of Bexarotene has been developed to provide chemotherapeutic effects within CTCL. Bexarotene has also been used in trials of breast cancer, lung cancer, glioblastoma multiforme and various neurodegenerative diseases. Yet the medication often causes serious side effects including hyperthyroidism, raised triglyceride levels and cutaneous toxicity. The focus of this research is to synthesize a hydroxylated analog compound of Bexarotene in efforts to produce a molecule that provides better chemotherapeutic effects while also lessening the various side effects caused. Synthesis of the molecule followed various organic chemistry techniques and reactions to create the final product. Melting point analysis, NMR and other various characterization data helped to confirm the synthesis of the intended molecule. Preliminary bioassay data results of the analog compound showed similar potency to that of Bexarotene. Further testing, however, will be required to determine the full pharmacokinetic profile of the molecule. Future direction of the research focuses on both further testing of the hydroxylated analog as well synthesizing newer analog compounds to find a molecule that can provide the best effects within cutaneous T-cell lymphoma and the various other diseases as well.

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Created

Date Created
  • 2018-05

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The Prey \u2014 Capture Kinematics of Rainbowfish, Melanotaenia splendida

Description

Rainbowfish, Melanotaenia splendida, are a common freshwater species in tropical regions of the world. They are members of the Atheriniformes (Atherinomorpha), the silverside fishes, which are known for some unusual

Rainbowfish, Melanotaenia splendida, are a common freshwater species in tropical regions of the world. They are members of the Atheriniformes (Atherinomorpha), the silverside fishes, which are known for some unusual feeding behaviors. Their close relatives, the Cypriniformes, such as mollies, guppies, and mosquitofish, are well studied and exhibit innovative morphologies associated with feeding. The third member of the Atherinomorphs, the Beloniformes, contains the recognizably odd needlefish, halfbeaks, and flying fishes. As a group, it is fair to say that the Atherinomorpha contain some pretty unusual fishes. The purpose of this project was to gain a further understanding of the unique feeding kinematics of Atheriniform fishes using the rainbowfish as an exemplar species. Feeding kinematics were quantified using high speed video recording unrestrained feeding events. Three feeding events from five individuals were analyzed frame by frame, from the time of the mouth opening to mouth closing. The X,Y coordinates of seven specific points were used to calculate the following kinematic variables: cranial elevation, gape distance, premaxillary protrusion, and hyoid depression. The contribution of cranial elevation to the strike was inconsistent. At times the fish raised the head as they expanded the mouth for prey capture, and at other times they did not. Cranial elevation is theoretically important for expanding the head during suction prey capture. Hyoid depression was more consistent, and clearly contributed to expansion of the head elements. Premaxillary protrusion contributed strongly to the event, and the jaws are closed with the premaxilla still protruded, facilitating a ‘nipping’ style jaw closure. A nipping style of prey capture is much like the Cyprinodontiforms, however, in rainbowfish, the event was quicker, and appeared to rely heavily on suction. We used both cleared and stained specimens and CT scans to investigate the underlying morphology of rainbowfish. These images revealed nearly microscopic teeth on the exterior of the jaws, and other features associated with feeding on highly elusive prey (i.e. prey that are mobile and likely to be able to escape predation). Further examination revealed a surprisingly well developed set of pharyngeal jaws, secondary to the oral jaws. The structure of the pharyngeal jaws suggested that most of the prey processing occurred within the pharynx.

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Created

Date Created
  • 2015-05

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Standard mapping protocols misestimate sex-biased gene expression

Description

There are several challenges to accurately inferring levels of transcription using RNA-sequencing (RNA-seq) data, including detecting and correcting for reference genome mapping bias. One potential confounder of RNA-seq analysis results

There are several challenges to accurately inferring levels of transcription using RNA-sequencing (RNA-seq) data, including detecting and correcting for reference genome mapping bias. One potential confounder of RNA-seq analysis results from the application of a standardized pipeline to samples of different sexes in species with chromosomal sex determination. The homology between the human X and Y chromosomes will routinely cause mismapping to occur, artificially biasing estimates of sex-biased gene transcription. For this reason we tested sex-specific mapping scenarios in humans on RNA-seq samples from the brains of 5 genetic females and 5 genetic males to assess how inferences of differential gene expression patterns change depending on the reference genome. We first applied a mapping protocol where we mapped all individuals to the entire human reference genome (complete), including the X and Y chromosomes, and computed differential expression between the set of genetic male and genetic female samples. We next mapped the genetic female samples (46,XX) to the human reference genome with the Y chromosome removed (Y-excluded) and the genetic male samples (46, XY) to the human reference genome (including the Y chromosome), but with the pseudoautosomal regions of the Y chromosome hard-masked (YPARs-masked) for the two sex-specific mappings. Using the complete and sex-specific mapping protocols, we compared the differential expression measurements of genetic males and genetic females from cuffDiff outputs. The second strategy called 33 additional genes as being differentially expressed between the two sexes when compared to the complete mapping protocol. This research provides a framework for a new standard of reference genome mappings to correct for sex-biased gene expression estimates that can be used in future studies.

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Created

Date Created
  • 2017-05

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Mathematical Analysis of Photoreceptor Degeneration in Retinal Detachment

Description

The retina is the lining in the back of the eye responsible for vision. When light photons hits the retina, the photoreceptors within the retina respond by sending impulses to

The retina is the lining in the back of the eye responsible for vision. When light photons hits the retina, the photoreceptors within the retina respond by sending impulses to the optic nerve, which connects to the brain. If there is injury to the eye or heredity retinal problems, this part can become detached. Detachment leads to loss of nutrients, such as oxygen and glucose, to the cells in the eye and causes cell death. Sometimes the retina is able to be surgically reattached. If the photoreceptor cells have not died and the reattachment is successful, then these cells are able to regenerate their outer segments (OS) which are essential for their functionality and vitality. In this work we will explore how the regrowth of the photoreceptor cells in a healthy eye after retinal detachment can lead to a deeper understanding of how eye cells take up nutrients and regenerate. This work uses a mathematical model for a healthy eye in conjunction with data for photoreceptors' regrowth and decay. The parameters for the healthy eye model are estimated from the data and the ranges of these parameter values are centered +/- 10\% away from these values are used for sensitivity analysis. Using parameter estimation and sensitivity analysis we can better understand how certain processes represented by these parameters change within the model as a result of retinal detachment. Having a deeper understanding for any sort of photoreceptor death and growth can be used by the greater scientific community to help with these currently irreversible conditions that lead to blindness, such as retinal detachment. The analysis in this work shows that maximizing the carrying capacity of the trophic pool and the rate of RDCVF, as well as minimizing nutrient withdrawal of the rods and the cones from the trophic pool results in both the most regrowth and least cell death in retinal detachment.

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Date Created
  • 2017-05

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The Effects of Serial Killers on FBI Policies & Investigations By: Joseph Muzupappa

Description

Serial killers have had a profound impact on the United States' most powerful law enforcement agency, the Federal Bureau of Investigation. Through a brief history of the FBI, the birth

Serial killers have had a profound impact on the United States' most powerful law enforcement agency, the Federal Bureau of Investigation. Through a brief history of the FBI, the birth of the Behavioral Analysis Unit is highlighted and criminal profiling is realized as a tool to apprehend these serial killers. Four serial killer cases are presented as important representations to illustrate the contributions that were made to the FBI's investigatory procedure. As serial killings make up only one percent of the murders in the U.S. each year, it is still evident that these cases have had a profound impact on the U.S.'s top law enforcement agency. The FBI has been able to react to each case more effectively than the last. Constant learning on the job, as each impactful case happens within a short time span from the last, has been a necessity for investigators and has been a prime strength of the FBI. There is no way to tell when an individual will begin to commit serial murder, so while the FBI's methods are not perfect, the Bureau has been able to respond in full to each challenge a new serial killer case has presented and arrest the guilty party. Through an analysis of the criminal profile, stereotypes attributed to serial killers, and the application of forensic evidence to serial killer investigations, the impact of the investigations of these cases by the FBI is examined. A real world application of the FBI's recommended procedure for a serial killer investigation is spotlighted and analyzed to determine its practicality in modern-day investigations.

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Created

Date Created
  • 2017-05

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Illness and Narrative Identity: Rewriting the Self

Description

Through this thesis, I intend to explore what sociologist Arthur Frank means when he describes illness as "a dangerous opportunity" (Frank, 1991, p. 1). It is my objective to more

Through this thesis, I intend to explore what sociologist Arthur Frank means when he describes illness as "a dangerous opportunity" (Frank, 1991, p. 1). It is my objective to more fully understand the lived experience of illness and how narrative can aid in transforming illness from tragic to transcendent. In doing so, it is first necessary to understand how illness differs from disease and how the medicalization of human health has displaced narrative from medical practice. Since illness is best understood as a lived experience, I will discuss how narrative is an exemplary means of communicating these experiences and restoring identity that is threatened by illness. Lastly, I will address how narrative might be more effectively utilized in the context of medicine, in respect to both patients and physicians. In this work, I propose that the opportunities posed by illness might be seized by actively exploring it by means of narrative expression. It is my hope that this thesis might contribute to extending the notion that narrative is a means of attributing greater meaning to illness and constructing a more complete, compassionate approach to medicine.

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Created

Date Created
  • 2017-05

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Ancestry Estimation in Forensic Anthropology: Osteological vs. Molecular Methods and Social Implications

Description

Ancestry estimation in forensic anthropology has been one of the most complex determinations to make from the human skeleton. There is a long history in biological anthropology using different morphological

Ancestry estimation in forensic anthropology has been one of the most complex determinations to make from the human skeleton. There is a long history in biological anthropology using different morphological characteristics from the skull and other areas of the skeleton but it remains a difficult estimation that always has some variability. Currently, more studies have been conducted in morphological and metric methods from the skull of ancestry estimation to better the accuracy of the determination. Since most forensic cases are not in the best condition, there also must be other estimation methods from other bones from the remains such as the cervical vertebrae and the femur. These methods have some degree of accuracy but are not as commonly used in forensic cases as the skull is. It seems that the best method for ancestry estimation is to use a combination of multiple methods, having multiple lines of evidence. With the advent of DNA, many researchers have started to study the use of DNA in ancestry estimation. Genetics can be used in ancestry estimation as certain populations have allele frequencies that can be quantified. Using ancestry informative markers (AIMS), DNA can be used to estimate the ancestry of an individual as well as the amount of admixture in the individual. Many different methods have been tested in genetic evaluation of ancestry and have been supported with good accuracy. However, DNA analysis is expensive and time consuming, putting more reliance on osteological methods. Social implications have had a tremendous impact on the fate of ancestry estimation in forensic anthropology. Anthropology has generally rejected the notion of races but it is still used in forensics due to how much it is inculcated into everyday society. Also, the overarching theme of admixture is becoming more prevalent in society. This causes the estimations in forensic anthropology to be extremely difficult. If more research into ancestry estimation does not continue, the determination will almost be impossible to be made.

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Created

Date Created
  • 2016-12

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Influence of Colchicine-Induced Polyploidy on Capsaicin Concentration in Peppers

Description

Colchicine is a chemical known for inhibiting mitosis during eukaryotic cellular reproduction by halting the tubulin formation necessary for the division of the chromosomes. The meristem is the primary source

Colchicine is a chemical known for inhibiting mitosis during eukaryotic cellular reproduction by halting the tubulin formation necessary for the division of the chromosomes. The meristem is the primary source of mitosis in developing flowering plants, and it was the focus of our research to determine if the hindrance of mitosis would interfere with the production of capsaicinoids within pungent pepper plants. Moruga Scorpion peppers have one of the world's highest concentration of capsaicinoids with Scoville Heat Units (SHU) averaging 1.2 million SHU (Bannister, 2012). The highest concentration of these capsaicinoids are within the placental and endocarp regions of the fruit, which are the primary location for capsaicinoid biosynthesis (Aza-Gonzalez & Nunez-Palenius, 2010). Hindering mitosis from the earliest stage of development could lead to phenotypic abnormalities within those placental and endocarp regions, quite possibly through the mechanism of the induced polyploidy. In many cases, this polymerization interference is beneficial in cultivating plants with characterized polyploidy due to its desired increased size of fruits and leaves. Due to the lethal nature of colchicine, there is threshold of effectiveness where it may induce polyploidy or it may result in fatality. This first stage of this research sought to determine which lethal dose was required to elicit a polyploid response or lead to seed unviability. The second stage was analyzing capsaicin concentration within the fruit of the mature dosed plants to determine whether there was an effect on the capsaicinoids, and whether polyploidy played a role in those effects. The final inspection of this research was in germinating the seeds from the hottest F1 pepper that had developed the fruit the slowest of all the doses, and determining whether there were any effects on the germination or seedling development.

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Created

Date Created
  • 2016-12