3,975 research outputs found

    Synthesis of human plasminogen by the liver

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    Genetic types of plasminogen were determined from a donor and a recipient before and after hepatic homotransplantation. Examination of the plasminogen types demonstrated that the liver is the principal site of synthesis of human plasminogen. Copyright © 1980 AAAS

    Neotropical bird communities in a human-modified landscape recently affected by two major hurricanes

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    Agriculture affects biodiversity on a global scale and especially in the Neotropics, leading to land-management challenges in which native wildlife is forced to interact with high-contrast landscape matrices. Further, the direct and indirect effects of hurricanes impacting native habitat in human-modified landscapes increases reliance on agricultural areas and high-contrast matrices. To understand how avian communities in a human-modified landscape respond to hurricane disturbance, we evaluated post-hurricane trends in species richness, density, structure, and functional and taxonomic composition in avian communities at tropical dry forest and in three agricultural habitats using point-count surveys. We compared our results to a similar study that took place years before the hurricanes in the study area. Similar to pre-hurricane trends, tropical dry forest provided key habitat for endemic species relative to agricultural areas, and tree orchards continued to serve as key secondary habitat for a high species richness and community evenness. However, tree orchards, along with cattle pastures and crop fields, failed to serve as successful buffers of hurricane disturbance by supporting half the estimated bird density of tropical dry forest. Cattle pasture and crop fields were both relatively species poor and had low community evenness compared to tropical dry forest and tree orchards after the hurricanes. Tropical dry forest had distinct species and feeding guild compositions compared to the agricultural habitats. All habitat types after the hurricanes had higher numbers of granivores and a reduction of carnivores compared to pre-hurricane levels. Land management in the study landscape needs to incorporate strategies that raise the hurricane resilience of agricultural areas while providing resources to support higher species richness and density in agricultural systems. Such strategies include the preservation of native trees and shrubs and allowing for the natural succession of habitat in unused areas in tree orchards, cattle pasture, and crop fields.Peer reviewe

    Planning and control for microassembly of structures composed of stress-engineered MEMS microrobots

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    We present control strategies that implement planar microassembly using groups of stress-engineered MEMS microrobots (MicroStressBots) controlled through a single global control signal. The global control signal couples the motion of the devices, causing the system to be highly underactuated. In order for the robots to assemble into arbitrary planar shapes despite the high degree of underactuation, it is desirable that each robot be independently maneuverable (independently controllable). To achieve independent control, we fabricated robots that behave (move) differently from one another in response to the same global control signal. We harnessed this differentiation to develop assembly control strategies, where the assembly goal is a desired geometric shape that can be obtained by connecting the chassis of individual robots. We derived and experimentally tested assembly plans that command some of the robots to make progress toward the goal, while other robots are constrained to remain in small circular trajectories (orbits) until it is their turn to move into the goal shape. Our control strategies were tested on systems of fabricated MicroStressBots. The robots are 240–280 µm × 60 µm × 7–20 µm in size and move simultaneously within a single operating environment. We demonstrated the feasibility of our control scheme by accurately assembling five different types of planar microstructures

    A Steerable, Untethered, 250x60 micron MEMS Mobile Micro-Robot

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    We present a steerable, electrostatic, untethered, MEMS micro-robot, with dimensions of 60 µm by 250 µm by 10 µm. This micro-robot is 1 to 2 orders of magnitude smaller in size than previous micro-robotic systems. The device consists of a curved, cantilevered steering arm, mounted on an untethered scratch drive actuator. These two components are fabricated monolithically from the same sheet of conductive polysilicon, and receive a common power and control signal through a capacitive coupling with an underlying electrical grid. All locations on the grid receive the same power and control signal, so that the devices can be operated without knowledge of their position on the substrate and without constraining rails or tethers. Control and power delivery waveforms are broadcast to the device through the capacitive power coupling, and are decoded by the electromechanical response of the device body. Individual control of the component actuators provides two distinct motion gaits (forward motion and turning), which together allow full coverage of a planar workspace (the robot is globally controllable). These MEMS micro-robots demonstrate turning error of less than 3.7 °/mm during forward motion, turn with radii as small as 176 µm, and achieve speeds of over 200 µm/sec, with an average step size of 12 nm. They have been shown to operate open-loop for distances exceeding 35 cm without failure, and can be controlled through teleoperation to navigate complex paths

    Towards precision medicine for pain: diagnostic biomarkers and repurposed drugs

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    We endeavored to identify objective blood biomarkers for pain, a subjective sensation with a biological basis, using a stepwise discovery, prioritization, validation, and testing in independent cohorts design. We studied psychiatric patients, a high risk group for co-morbid pain disorders and increased perception of pain. For discovery, we used a powerful within-subject longitudinal design. We were successful in identifying blood gene expression biomarkers that were predictive of pain state, and of future emergency department (ED) visits for pain, more so when personalized by gender and diagnosis. MFAP3, which had no prior evidence in the literature for involvement in pain, had the most robust empirical evidence from our discovery and validation steps, and was a strong predictor for pain in the independent cohorts, particularly in females and males with PTSD. Other biomarkers with best overall convergent functional evidence for involvement in pain were GNG7, CNTN1, LY9, CCDC144B, and GBP1. Some of the individual biomarkers identified are targets of existing drugs. Moreover, the biomarker gene expression signatures were used for bioinformatic drug repurposing analyses, yielding leads for possible new drug candidates such as SC-560 (an NSAID), and amoxapine (an antidepressant), as well as natural compounds such as pyridoxine (vitamin B6), cyanocobalamin (vitamin B12), and apigenin (a plant flavonoid). Our work may help mitigate the diagnostic and treatment dilemmas that have contributed to the current opioid epidemic

    C-Reactive protein and risk of ESRD: results from the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT)

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    Background: To better understand a potential association of elevated C-reactive protein (CRP) level with progression of chronic kidney disease (CKD), we examined the relationship of CRP level with the development of end-stage renal disease (ESRD) in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT). Study Design Post hoc analysis of a randomized controlled trial. Setting & Participants: 4,038 patients with type 2 diabetes, CKD, and anemia in TREAT. Predictor: Baseline serum CRP concentrations. Outcomes: The primary outcome was development of ESRD; secondary outcomes included doubling of serum creatinine level, a composite of ESRD/serum creatinine doubling, and a composite of death or ESRD. Measurements: We fit unadjusted and adjusted Cox regression models to test the association of baseline CRP level with time to the development of the outcomes of interest. Results: Mean age of participants was 67 years, 43% were men, and 64% were white. Approximately half (48%) the patients had CRP levels > 3.0 mg/L; 668 patients developed ESRD, and 1,270 developed the composite outcome of death or ESRD. Compared with patients with baseline CRP levels ≤ 3.0 mg/L, those with moderately/markedly elevated CRP levels (≥6.9 mg/L; 24% of patients) had a higher adjusted risk for ESRD (HR, 1.32; 95% CI, 1.07-1.63) and the composite outcome of death or ESRD (HR, 1.41; 95% CI, 1.21-1.64). Although nonsignificant, similar trends were noted in competing-risk models. Limitations: Results may not be generalizable to nondiabetic CKD or diabetic CKD in the absence of anemia. Conclusions: Elevated baseline CRP levels are common in type 2 diabetic patients with anemia and CKD and are associated with the future development of ESRD and the composite of death or ESRD

    The Impact of Environmental Factors on Emergency Medicine Resident Career Choice

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    Objective: To evaluate the impact of environmental factors on emergency medicine (EM) resident career choice. Methods: Program directors of all U.S. EM residencies were surveyed in November 1997. A 22-item questionnaire assessed resources allocated to research, fellowship availability, academic productivity of faculty and residents, and career choices of residency graduates. Results: The response rate was 83%. The program director (mean ± SD) estimates of resident career choice were as follows: 27.8 ± 19.1% pursued academic positions with emphasis on teaching, 5.4 ± 9.8% pursued academic positions with emphasis on research, and 66.8 ± 23.1%, pursued private practice positions. In addition, 5.70 ± 6.13% of the residency graduates were estimated to seek felloship training. Univariate analyses demonstrated that increasing departmental funding for research, having substantial resource availability (defined as having at least two of the following: dedicated laboratory space; support for a laboratory research technician/assistant, a clinical research nurse or study coordinator, a statistician, or an assistant with a PhD degree), a greater number of peer-reviewed publications by residents (r = 0.22; p = 0.08), and a greater number of peer-reviewed publications by faculty (r = 0.26; p = 0.04) positively correlated with the percentage of graduates who pursue academic research careers. Using multiple regression, however, increasing intramural funding and the presence of substantial resource availability were the only variables predictive of resident pursuit of an academic research career. Conclusion: Modification of the EM training environment may influence the career choices of graduates. Specifically, greater commitment of departmental funds and support of resources for research may enhance the likelihood of a trainee's choosing an academic research career.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72940/1/j.1553-2712.1999.tb00387.x.pd

    Governance in Large Nonprofit Health Systems: Current Profile and Emerging Patterns

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    From the foreword: Nonprofit healthcare organizations are not exempt from good governance. In fact, more today than ever, the hospitals and health care systems of this country must have the discipline and commitment to organize their governance structures and practices to provide forward-thinking leadership and stand up to scrutiny from any type of evaluation and review. As we move from “sick care” organizations to “health care” organizations with accountability for the health of the population of our communities from birth to end-of-life, the role of governance becomes even more critical. Fourteen of the largest and most notable health care systems in this country have been included in a research study to examine their governance structures and practices in relation to nine benchmarks. The CEOs and board members of these organizations were interviewed about their structures, processes and cultures, and then compared to national best practices. The study also included close review of pertinent system documents. This report is a must read for hospital and health care system CEOs and boards. It provides evidence-based outcomes that will assist an organization in advancing its governance practices. This study outlines critical success factors for governance structure and performance. It answers many questions that boards may be struggling with today and provides advancing actions. The research methodology is thorough and reliable with specific outcomes that provide high-performance opportunities. Each CEO who participated in the research study has written about a best practice in his or her respective organization that advances governance responsibility. These insights add a personal dimension to this report.https://uknowledge.uky.edu/hsm_book/1000/thumbnail.jp
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