357 research outputs found

    Determination of phylo-group diversity of \u3cem\u3eEscherichia coli\u3c/em\u3e in environmental sand samples collected from a South Carolina beach

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    Escherichia coli (E. coli) is a common bacterial species that can persist in many environments found around the world. One environment where it can be found that is of particular concern is an oceanic beach, where it can serve as an indicator of both fecal and microbial pollution. While the majority of strains of E. coli are non-pathogenic to humans, some phylo-groups are associated with virulent strains and could cause disease. Therefore, it is of critical concern that we determine where this E. coli is coming from and whether it is potentially harmful to human health and well-being. In this study, we attempted to answer this question by using a newly developed molecular technique, which allows us to identify which phylo-groups environmental isolates of E. coli belong to. Classification into phylo-groups can help infer the source of the pollution. For this analysis, we collected sand samples from Folly Beach, SC, which is one of the most visited beaches in the Southeastern US. In our analysis, we identified environmental isolates of E. coli that differ from the lab strain and belong to two distinct phylo-groups including phylo-group A, which is likely from human fecal contamination and phylo-group B1, which is likely from a domesticated and/or wild animal source. The same molecular technique was altered to test for virulence factors of E. coli, and all isolates showed a band corresponding to a virulence factor, but further analysis is needed to determine the validity of this technique. Collectively, our findings indicate that multiple types of E. coli are able to persist in these environments and that more research is needed to determine whether these strains are of public health concern

    An investigation into Atterberg limits and their suitability for assessing the shrinkage and swelling characteristics of clay soils for foundation design.

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    Clay soils shrink and swell with changes in moisture content. This can be exacerbated in the presence of trees, and in the vicinity of buildings, the resultant effects can cause structural damage. For foundation design in such circumstances in the UK, reference is often made to guidelines published by the National House Building Council (NHBC), which were primarily written for low-rise residential structures. These guidelines are based on a clay shrink / swell potential assessed using Atterberg Limits and a 'water demand' classification for trees. Atterberg limits are semi-empirical tests that assess a fraction of a soil sample which passes an arbitrary sieve size. The structural features of clay soils, mineralogy, chemistry, prior stress history and cyclic effects all influence the magnitude of volumetric change. Atterberg limits do not directly measure any of these features but have been related to some of them empirically. This paper reviews the processes of clay shrinkage and swelling and the applicability of the Atterberg limits in the assessment of volume change potential. It concludes that modifications to the NHBC guidelines can make designs more site specific. However, because the guidelines are based on a cost - benefit analysis, they will over-design foundations for structures other than low rise residential houses and will not be relevant for others. It is concluded that a more appropriate analysis should be based on a wider overall assessment of all the available soil/site information, in conjunction with a simple assessment of plasticity

    Microgravity Drill and Anchor System

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    This work is a method to drill into a rock surface regardless of the gravitational field or orientation. The required weight-on-bit (WOB) is supplied by a self-contained anchoring mechanism. The system includes a rotary percussive coring drill, forming a complete sampling instrument usable by robot or human. This method of in situ sample acquisition using micro - spine anchoring technology enables several NASA mission concepts not currently possible with existing technology, including sampling from consolidated rock on asteroids, providing a bolt network for astronauts visiting a near-Earth asteroid, and sampling from the ceilings or vertical walls of lava tubes and cliff faces on Mars. One of the most fundamental parameters of drilling is the WOB; essentially, the load applied to the bit that allows it to cut, creating a reaction force normal to the surface. In every drilling application, there is a minimum WOB that must be maintained for the system to function properly. In microgravity (asteroids and comets), even a small WOB could not be supported conventionally by the weight of the robot or astronaut. An anchoring mechanism would be needed to resist the reactions, or the robot or astronaut would push themselves off the surface and into space. The ability of the system to anchor itself to a surface creates potential applications that reach beyond use in low gravity. The use of these anchoring mechanisms as end effectors on climbing robots has the potential of vastly expanding the scope of what is considered accessible terrain. Further, because the drill is supported by its own anchor rather than by a robotic arm, the workspace is not constrained by the reach of such an arm. Yet, if the drill is on a robotic arm, it has the benefit of not reflecting the forces of drilling back to the arm s joints. Combining the drill with the anchoring feet will create a highly mobile, highly stable, and highly reliable system. The drilling system s anchor uses hundreds of microspine toes that independently find holes and ledges on a rock to create an anchor. Once the system is anchored, a linear translation mechanism moves the drill axially into the surface while maintaining the proper WOB. The linear translation mechanism is composed of a ball screw and stepper motor that can translate a carriage with high precision and applied load. The carriage slides along rails using self-aligning linear bearings that correct any axial misalignment caused by bending and torsion. The carriage then compresses a series of springs that simultaneously transmit the load to the drill along the bit axis and act as a suspension that compensates for the vibration caused by percussive drilling. The drill is a compacted, modified version of an off-the-shelf rotary percussive drill, which uses a custom carbide-tipped coring bit. By using rotary percussive drilling, the drill time is greatly reduced. The percussive action fractures the rock debris, which is removed during rotation. The final result is a 0.75-in. (.1.9- cm) diameter hole and a preserved 0.5- in. (.1.3-cm) diameter rock core. This work extends microspine technology, making it applicable to astronaut missions to asteroids and a host of robotic sampling concepts. At the time of this reporting, it is the first instrument to be demonstrated using microspine anchors, and is the first self-contained drill/anchor system to be demonstrated that is capable of drilling in inverted configurations and would be capable of drilling in microgravity

    Systems and Methods for Gravity-Independent Gripping and Drilling

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    Systems and methods for gravity independent gripping and drilling are described. The gripping device can also comprise a drill or sampling devices for drilling and/or sampling in microgravity environments, or on vertical or inverted surfaces in environments where gravity is present. A robotic system can be connected with the gripping and drilling devices via an ankle interface adapted to distribute the forces realized from the robotic system

    A Dietary-Wide Association Study (DWAS) of Environmental Metal Exposure in US Children and Adults

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    Background: A growing body of evidence suggests that exposure to toxic metals occurs through diet but few studies have comprehensively examined dietary sources of exposure in US populations. Purpose: Our goal was to perform a novel dietary-wide association study (DWAS) to identify specific dietary sources of lead, cadmium, mercury, and arsenic exposure in US children and adults. Methods: We combined data from the National Health and Nutrition Examination Survey with data from the US Department of Agriculture’s Food Intakes Converted to Retail Commodities Database to examine associations between 49 different foods and environmental metal exposure. Using blood and urinary biomarkers for lead, cadmium, mercury, and arsenic, we compared sources of dietary exposure among children to that of adults. Results: Diet accounted for more of the variation in mercury and arsenic than lead and cadmium. For instance we estimate 4.5% of the variation of mercury among children and 10.5% among adults is explained by diet. We identified a previously unrecognized association between rice consumption and mercury in a US study population – adjusted for other dietary sources such as seafood, an increase of 10 g/day of rice consumption was associated with a 4.8% (95% CI: 3.6, 5.2) increase in blood mercury concentration. Associations between diet and metal exposure were similar among children and adults, and we recapitulated other known dietary sources of exposure. Conclusion: Utilizing this combination of data sources, this approach has the potential to identify and monitor dietary sources of metal exposure in the US population

    Robotics Platforms Incorporating Manipulators Having Common Joint Designs

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    Manipulators in accordance with various embodiments of the invention can be utilized to implement statically stable robots capable of both dexterous manipulation and versatile mobility. Manipulators in accordance with one embodiment of the invention include: an azimuth actuator; three elbow joints that each include two actuators that are offset to allow greater than 360 degree rotation of each joint; a first connecting structure that connects the azimuth actuator and a first of the three elbow joints; a second connecting structure that connects the first elbow joint and a second of the three elbow joints; a third connecting structure that connects the second elbow joint to a third of the three elbow joints; and an end-effector interface connected to the third of the three elbow joints

    Increasing HPV Vaccination in a Network of Pediatric Clinics using a Multi-component Approach

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    Background: Despite continued public health efforts to increase human papillomavirus (HPV) vaccination among adolescents, initiation remains below the level needed to reach the Healthy People 2020 goal of 80% series completion by age 13. Methods: We developed, implemented, and evaluated a multi-component program that used evidence-based strategies to increase HPV vaccine initiation in a network of 51 pediatric clinics in Houston, Texas. Our target populations were the clinic network, healthcare providers, male and female patients ages 11-17, and their parents. The program, called the Adolescent Vaccination Program (AVP), was conducted from March 2016 through March 2019 and contained strategies to increase vaccination including: HPV immunization champions; provider assessment and feedback; provider continuing education; provider reminders; and patient reminders. We used a single group pre/post design with an external comparison – NIS-Teen. Our primary outcome was initiation of the HPV vaccine based on the electronic health record. We used interrupted time series analysis (ITSA) to measure change in initiation over time. We calculated monthly, quarterly, and annual rates of initiation for each physician, clinic, and the network. We examined patterns of initiation by patient age, sex, race/ethnicity, and type of insurance. Results: By the end of the project, the 51 clinics averaged 77.4% initiation. Rates increased annually from September 2015 through March 2019. ITSA analysis over 75 months showed an increase in vaccine initiation of 0.396% per month from the introduction of the program in March 2016. Average individual clinic improvement was 0.37% per month ranging from -0.04% to 0.68% through March 2019. Data for the 11-12 year olds, the target age group for initiating the vaccine, showed a greater percentage increase (54.2%) compared with the 13-17 year olds (29.6%). Hispanics and African Americans had the highest initiation rates in all years while non-Hispanic whites had the lowest. Families without insurance had the lowest rates while those with Medicaid/Medicare had the highest. Conclusions: We observed a secular trend upward in both the network and NIS-Teen data; however, the network showed a steeper increase. The AVP is a promising program of strategies to increase HPV vaccination in a clinic setting

    Development of core entrustable professional activities linked to a competency-based veterinary education framework

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    Purpose: Despite the adoption of competency-based education in some veterinary schools over the past 15 years, only recently has a concerted effort been directed toward this in veterinary education internationally. Methods: In 2015, educational leaders from the Association of American Veterinary Medical Colleges (AAVMC) member schools came together with a strong call to action to create shared tools for clinical competency assessment. Results: This resulted in the formation of the AAVMC Competency-Based Veterinary Education (CBVE) Working Group, which then embarked on the creation of a shared competency framework and the development of eight core entrustable professional activities (EPAs) linked to this framework. Conclusions: This paper will report on the development of these EPAs and their integration with the concurrently-developed CBVE Framework

    Automated interpretation of systolic and diastolic function on the echocardiogram:a multicohort study

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    Background: Echocardiography is the diagnostic modality for assessing cardiac systolic and diastolic function to diagnose and manage heart failure. However, manual interpretation of echocardiograms can be time consuming and subject to human error. Therefore, we developed a fully automated deep learning workflow to classify, segment, and annotate two-dimensional (2D) videos and Doppler modalities in echocardiograms. Methods: We developed the workflow using a training dataset of 1145 echocardiograms and an internal test set of 406 echocardiograms from the prospective heart failure research platform (Asian Network for Translational Research and Cardiovascular Trials; ATTRaCT) in Asia, with previous manual tracings by expert sonographers. We validated the workflow against manual measurements in a curated dataset from Canada (Alberta Heart Failure Etiology and Analysis Research Team; HEART; n=1029 echocardiograms), a real-world dataset from Taiwan (n=31 241), the US-based EchoNet-Dynamic dataset (n=10 030), and in an independent prospective assessment of the Asian (ATTRaCT) and Canadian (Alberta HEART) datasets (n=142) with repeated independent measurements by two expert sonographers. Findings: In the ATTRaCT test set, the automated workflow classified 2D videos and Doppler modalities with accuracies (number of correct predictions divided by the total number of predictions) ranging from 0·91 to 0·99. Segmentations of the left ventricle and left atrium were accurate, with a mean Dice similarity coefficient greater than 93% for all. In the external datasets (n=1029 to 10 030 echocardiograms used as input), automated measurements showed good agreement with locally measured values, with a mean absolute error range of 9–25 mL for left ventricular volumes, 6–10% for left ventricular ejection fraction (LVEF), and 1·8–2·2 for the ratio of the mitral inflow E wave to the tissue Doppler e' wave (E/e' ratio); and reliably classified systolic dysfunction (LVEF <40%, area under the receiver operating characteristic curve [AUC] range 0·90–0·92) and diastolic dysfunction (E/e' ratio ≥13, AUC range 0·91–0·91), with narrow 95% CIs for AUC values. Independent prospective evaluation confirmed less variance of automated compared with human expert measurements, with all individual equivalence coefficients being less than 0 for all measurements. Interpretation: Deep learning algorithms can automatically annotate 2D videos and Doppler modalities with similar accuracy to manual measurements by expert sonographers. Use of an automated workflow might accelerate access, improve quality, and reduce costs in diagnosing and managing heart failure globally. Funding: A*STAR Biomedical Research Council and A*STAR Exploit Technologies
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