1,559 research outputs found

    Ionizing Radiation Affects Epigenetic Programming in Adolescent Mice

    Get PDF
    poster abstractHumans are exposed to low and mild doses of radiation frequently, ranging from the natural environment to medical procedures like x-ray and CT scans. Ionizing radiation of various doses has been known to potentially cause not only cellular but also genomic changes. Here, we demonstrate that epigenetics is also altered by the radiation. Epigenetics is a chemical coding above the gene, which plays critical roles in brain development, cognitive aberrations and other neurological impairments. How radiation, as an external environmental factor, causes epigenetic change is not understood. DNA methylation, key in epigenetics, including 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) have been shown to either suppress or activate gene transcription. To aid in elucidating the role in which radiation affects epigenetic outcomes, we examined the effects of radiation on both epigenetic and phenotypic markers within the hippocampus. In this study we treated, via x-ray C57BL/6 mice, postnatal day (P) 21 with various doses (2Gy-4.5Gy) of radiation coupled with varying frequencies (0.5 Gy x 4, 1.5 Gy x 3, or 4.5Gy x 1) during a 4-week period. We used immunohistochemistry staining with cell proliferation, transcription and epigenetic markers. We found loss of 5mC in the sub-granular layer of the dentate gyrus (DG) in the upper and lower arms. Likewise a loss of 5hmC in the sub-granular layer of the DG, as well as in the cornu Ammonis (CA) layers 1 and 2. There was also loss of a transcriptional activation marker within the DG of the hippocampus. Furthermore, decreased cell proliferation in the adult neurogenesis in the hippocampus was found. Exposure to ionizing radiation altered the normal epigenetic profile of the mice. Understanding the mechanism by which ionizing radiation affects epigenetic programming will provide insight into how to develop protection against the potentially harmful risks associated with radiation exposure

    Ionizing Radiation Affects Epigenetic Programming in Young Adult Mice

    Get PDF
    Humans are exposed to low and mild doses of radiation frequently, ranging from the natural environment to medical procedures like x-ray and CT scans. Ionizing radiation of various doses has been known to cause not only cellular and genomic changes, but specific neurological systems such as the limbic system have been indicated to be particularly vulnerable. Here, we demonstrated that epigenetics is also altered by radiation. Epigenetics is a subtle chemical coding above the gene, which plays a critical role in brain development, and downstream can cause the onset of cognitive aberrations and other neurological impairments. How radiation as an external environmental factor causes epigenetic changes is not clearly understood. DNA methylation, including 5-methylcytosine (5M) and 5-hydroxymethylcytosine (5-hmC) have been shown to either suppress or activate gene transcription and as such are key epigenetic players. To elucidate the role of radiation in epigenetic outcomes, we examined epigenetic, phenotypic and transcriptional markers via immunohistochemistry, in the hippocampus and cortex. In this study C57BL/6 mouse (postnatal day 21 (P21)) began a 4-week radiation treatment of various doses totaling (2Gy-4.5Gy) via global head targeting CT exposure. We found a loss of 5M and 5-hmC as well as transcriptional markers within regions of the hippocampus and cortex. There was a significant decrease in cell proliferation in the hippocampus- specifically, in the region responsible for adult neurogenesis. The cingulate cortex (a region adjacent to the hippocampus) also exhibited dramatic alterations in several epigenetic and transcriptional markers, indicating the vulnerability of the limbic system in radiation exposure. Understanding the mechanism by which ionizing radiation affects epigenetic programming will provide insight into the transmissibility of external factors to biological systems. Additionally, this work can aid the development of protective strategies against the harmful risks associated with radiation exposure

    Geostatistical and stochastic study of flow and tracer transport in the unsaturated zone at Yucca Mountain

    Full text link
    Yucca Mountain has been proposed by the U.S. Department of Energy as the nation’s long-term, permanent geologic repository for spent nuclear fuel or high-level radioactive waste. The potential repository would be located in Yucca Mountain’s unsaturated zone (UZ), which acts as a critical natural barrier delaying arrival of radionuclides to the water table. Since radionuclide transport in groundwater can pose serious threats to human health and the environment, it is important to understand how much and how fast water and radionuclides travel through the UZ to groundwater. The UZ system consists of multiple hydrogeologic units whose hydraulic and geochemical properties exhibit systematic and random spatial variation, or heterogeneity, at multiple scales. Predictions of radionuclide transport under such complicated conditions are uncertain, and the uncertainty complicates decision making and risk analysis. This project aims at using geostatistical and stochastic methods to assess uncertainty of unsaturated flow and radionuclide transport in the UZ at Yucca Mountain. Focus of this study is parameter uncertainty of hydraulic and transport properties of the UZ. The parametric uncertainty arises since limited parameter measurements are unable to deterministically describe spatial variability of the parameters. In this project, matrix porosity, permeability and sorption coefficient of the reactive tracer (neptunium) of the UZ are treated as random variables. Corresponding propagation of parametric uncertainty is quantitatively measured using mean, variance, 5th and 95th percentiles of simulated state variables (e.g., saturation, capillary pressure, percolation flux, and travel time). These statistics are evaluated using a Monte Carlo method, in which a three-dimensional flow and transport model implemented using the TOUGH2 code is executed with multiple parameter realizations of the random model parameters

    A Data-Driven Behavior Modeling and Analysis Framework for Diabetic Patients on Insulin Pumps

    Get PDF
    About 30%-40% of Type 1 Diabetes (T1D) patients in the United States use insulin pumps. Current insulin infusion systems require users to manually input meal carb count and approve or modify the system-suggested meal insulin dose. Users can give correction insulin boluses at any time. Since meal carbohydrates and insulin are the two main driving forces of the glucose physiology, the user-specific eating and pump-using behavior has a great impact on the quality of glycemic control. In this paper, we propose an “Eat, Trust, and Correct” (ETC) framework to model the T1D insulin pump users’ behavior. We use machine learning techniques to analyze the user behavior from a clinical dataset that we collected on 55 T1D patients who use insulin pumps. We demonstrate the usefulness of the ETC behavior modeling framework by performing in silico experiments. To this end, we integrate the user behavior model with an individually parameterized glucose physiological model, and perform probabilistic model checking on the user-in-the-loop system. The experimental results show that switching behavior types can significantly improve a patient’s glycemic control outcomes. These analysis results can boost the effectiveness of T1D patient education and peer support

    Examining the Impact of Provenance-Enabled Media on Trust and Accuracy Perceptions

    Full text link
    In recent years, industry leaders and researchers have proposed to use technical provenance standards to address visual misinformation spread through digitally altered media. By adding immutable and secure provenance information such as authorship and edit date to media metadata, social media users could potentially better assess the validity of the media they encounter. However, it is unclear how end users would respond to provenance information, or how to best design provenance indicators to be understandable to laypeople. We conducted an online experiment with 595 participants from the US and UK to investigate how provenance information altered users' accuracy perceptions and trust in visual content shared on social media. We found that provenance information often lowered trust and caused users to doubt deceptive media, particularly when it revealed that the media was composited. We additionally tested conditions where the provenance information itself was shown to be incomplete or invalid, and found that these states have a significant impact on participants' accuracy perceptions and trust in media, leading them, in some cases, to disbelieve honest media. Our findings show that provenance, although enlightening, is still not a concept well-understood by users, who confuse media credibility with the orthogonal (albeit related) concept of provenance credibility. We discuss how design choices may contribute to provenance (mis)understanding, and conclude with implications for usable provenance systems, including clearer interfaces and user education.Comment: Accepted to CSCW 202
    • …
    corecore