2,754 research outputs found

    EXP-SA: Explosives Tracking: A Microsystem for Detection of Bacterial Endospores as Self-Replicating Nucleic Acid Taggants

    Get PDF
    This proposal presents an integrated research and educational plan directed toward the production, detection, and identification of bacterial endospore taggants for explosive tracking. While the most immediate application of the research is related to stemming the activities of bioterrorists, the anticipated fundamental advances in bioengineering and sensor science and engineering will have significant societal relevance to other applications, including first-responder activities, healthcare, food safety, and pollution avoidance and mitigation. Intellectual Merit The investigators propose to combine bioengineering of Bacillus stearothermophilus endospores with microdevices for sample processing and taggant identification. A surface acoustic wave (SAW) microdroplet mixing/transport/incubator system will be coupled with molecular padlock probe technology for sensitive identification of bioengineered endospores. The specific research tasks are to: (i) Generate a number of different Bacillus spores, each with a unique DNA sequence or sequences spliced into its genome; (ii) Investigate and identify the optimal SAW device designs needed to germinate spores, lyse vegetative bacteria, transport, mix, and heat microdroplet samples; (iii) Design subsystems for DNA isolation; (iv) Develop a fluorescence-based molecular padlock probe system for DNA identification that can operate effectively in conjunction with the SAW fabrication microsystem platform; (v) Fabricate and test the proposed prototype identification system. Broader Impacts Broader impacts will be achieved through the following programs and activities to: (i) Train and interact with high school audiences through two major ongoing programs at University of Maine (UMaine), NSF Research Experiences for Teachers (RET) and the GK-12 Sensors; (ii) Involve undergraduates from Maine and other institutions directly into the research project under the umbrella of the ongoing NSF Research Experience for Undergraduates (REU) program at the UMaine; (iii) Identify appropriate Capstone projects for undergraduates involving cross-disciplinary research and design projects; (iv) Enhance existing graduate level courses (1) Microscale Bioengineering and (2) Design and Fabrication of Acoustic Wave Devices by incorporating research results into each course; (v) Contribute to the interdisciplinary multi-institutional NSF Integrative Graduate Education and Research Traineeship (IGERT) program in functional genomics, which involves UMaine, the Jackson Laboratory, and the Maine Medical Center Research Institute; (vi) Provide thesis topics for M.S. and Ph.D. students; (vii) Disseminate the research and educational material on a project website, and through conferences and printed literature. Project Outcomes ReportNew investigative tools are desperately needed to determine the origin and transit routes of contraband explosive materials, and the individuals who transport them. A powerful strategy for tracking and identifying specific lots of explosives is the incorporation or labeling with pre-and post-detonation identification tags, or taggants. This project involves the production, detection, and identification of bacterial endospore taggants for explosive tracking. It combines bioengineering of environmentally resistant Geobacillus thermoglucosidasius endospores with development of microdevices for sample processing and taggant identification. A surface acoustic wave (SAW) bacterial lysis system is coupled with on-chip fluorescence-based quantitative polymerase chain reaction (PCR) for identification of bioengineered endospores.Geobacillus spores with a unique DNA sequence encoded in well-retained plasmids have been generated. Optimal SAW device structures have been designed, fabricated and tested for lysis of the vegetative bacteria. A number of on-chip structures for multiplex PCR analysis have been created and tested. DNA release and fluorescence-based PCR analysis for identification of specific genomic DNA sequences can now be interfaced to the SAW microsystem platform to comprise an important part of the overall detection system. We anticipate that aspects of this technology will be useful for tracking contraband materials such as explosives, environmental monitoring, and potentially medical diagnostic applications. This project has fostered the multidisciplinary training of numerous undergraduate and graduate students in molecular biology, microbiology, biochemistry, and bioengineering

    ESUR guidelines for MR imaging of the sonographically indeterminate adnexal mass: an algorithmic approach

    Get PDF
    A significant proportion of adnexal masses detected by sonography are indeterminate. Either their organ of origin is uncertain or it is unclear whether their nature is benign or malignant. MR imaging of the sonographically indeterminate adnexal mass can resolve most of these uncertainties. Most indeterminate masses result from common benign conditions and women with such masses can avoid unnecessary or inappropriate surgery. For the minority of women whose masses are malignant, use of MR imaging rather than a ‘wait and watch’ strategy of repeat ultrasound (US) results in a more timely diagnosis. There are simple diagnostic steps in the MR imaging assessment which direct an algorithmic and problem-solving approach based on signal characteristics and morphology. MR imaging should provide a more timely diagnosis and, thereby, guide the management of the patient with reduced costs of investigation and treatment

    A large set of microsatellites for the highly invasive earthworm Amynthas corticis predicted from low coverage genomes

    Get PDF
    Invasive species can significantly affect local biodiversity and create important challenges for conservation. They usually present an outstanding plasticity that permits the adaptation to the new environments. Understanding their genetic background is fundamental to better comprehend invasion dynamics and elaborate proper management plans as well to infer population and evolutionary patterns. Here, we present a reasonable set of tools for the study of a highly invasive earthworm, the megascolecid Amynthas corticis. We designed in silico a large set of primers targeting microsatellite regions (ca. 9400) from two low coverage genomes presented here. This study provides 154 high quality primer pairs targeting polymorphic repeats conserved in two Amynthas corticis mitochondrial lineages. From this dataset, a set of primer pairs (15) was validated by polymerase chain reaction with 86% consistent amplification, confirming the accuracy of the in silico prediction. Nine of the primer pairs tested were selected for population genetics and presented polymorphism in the studied populations, thus showing promising potential for future studies of this global invasive species. The nuclear markers used in this study appear to recapitulate and complement the mitochondrial relationships found in a previous study. Interestingly, all genotyped individuals showed at least one triploid locus profile among the tested loci, which may be evidence of polyploidy associated to their life history, in particular to asexual reproduction by parthenogenesis

    Fragile States, Infectious Disease and Health Security: The Case for Timor-Leste

    Get PDF
    Timor-Leste is a very young and developing nation state. Endemic infectious disease and weakened health security coupled with its growing and inclusive public institutions keep Timor-Leste fragile and in transition on the spectrum of state stability. The objective here is to systematically review Timor-Leste's state and public health successes, showing how a fragile state can consistently improve its status on the continuum of stability and improve health security for the population. The case study follows a state case study approach, together with a disease burden review and a basic description of the health portrait in relation to Timor-Leste's fragile state status. Disease burden and health security are directly proportional to state stability and indirectly proportional to state failure. Timor-Leste is a clear example of how public health can feed into increased state stability. Our discussion attempts to describe how the weak and fragile island nation of Timor-Leste can continue on its current path of transition to state stability by increasing health security for its citizens. We surmise that this can be realized when public policy focuses on primary healthcare access, inclusive state institutions, basic hygiene and preventative vaccination programs. Based on our review, the core findings indicate that by increasing health security, a positive feedback loop of state stability follows. The use of Timor-Leste as a case study better describes the connection between public health and health security; and state stability, development and inclusive state institutions that promote health security

    Fragile States, Infectious Disease and Health Security: The Case for Timor-Leste

    Get PDF
    Timor-Leste is a very young and developing nation state. Endemic infectious disease and weakened health security coupled with its growing and inclusive public institutions keep Timor-Leste fragile and in transition on the spectrum of state stability. The objective here is to systematically review Timor-Leste's state and public health successes, showing how a fragile state can consistently improve its status on the continuum of stability and improve health security for the population. The case study follows a state case study approach, together with a disease burden review and a basic description of the health portrait in relation to Timor-Leste's fragile state status. Disease burden and health security are directly proportional to state stability and indirectly proportional to state failure. Timor-Leste is a clear example of how public health can feed into increased state stability. Our discussion attempts to describe how the weak and fragile island nation of Timor-Leste can continue on its current path of transition to state stability by increasing health security for its citizens. We surmise that this can be realized when public policy focuses on primary healthcare access, inclusive state institutions, basic hygiene and preventative vaccination programs. Based on our review, the core findings indicate that by increasing health security, a positive feedback loop of state stability follows. The use of Timor-Leste as a case study better describes the connection between public health and health security; and state stability, development and inclusive state institutions that promote health security

    On the origin of fluorine in the Milky Way

    Full text link
    The main astrophysical factories of fluorine (19F) are thought to be Type II supernovae, Wolf-Rayet stars, and the asymptotic giant branch (AGB) of intermediate mass stars. We present a model for the chemical evolution of fluorine in the Milky Way using a semi-analytic multi-zone chemical evolution model. For the first time, we demonstrate quantitatively the impact of fluorine nucleosynthesis in Wolf-Rayet and AGB stars. The inclusion of these latter two fluorine production sites provides a possible solution to the long-standing discrepancy between model predictions and the fluorine abundances observed in Milky Way giants. Finally, fluorine is discussed as a possible probe of the role of supernovae and intermediate mass stars in the chemical evolution history of the globular cluster omega Centauri.Comment: 7 pages, 4 figures. MNRAS in pres

    Pegasus Simulator: An Isaac Sim Framework for Multiple Aerial Vehicles Simulation

    Full text link
    Developing and testing novel control and motion planning algorithms for aerial vehicles can be a challenging task, with the robotics community relying more than ever on 3D simulation technologies to evaluate the performance of new algorithms in a variety of conditions and environments. In this work, we introduce the Pegasus Simulator, a modular framework implemented as an NVIDIA Isaac Sim extension that enables real-time simulation of multiple multirotor vehicles in photo-realistic environments, while providing out-of-the-box integration with the widely adopted PX4-Autopilot and ROS2 through its modular implementation and intuitive graphical user interface. To demonstrate some of its capabilities, a nonlinear controller was implemented and simulation results for two drones performing aggressive flight maneuvers are presented. Code and documentation for this framework are also provided as supplementary material
    corecore