868 research outputs found

    Manufacturing and Evaluation of a Biologically Inspired Engineered MAV Wing Compared to the Manduca Sexta Wing Under Simulated Flapping Conditions

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    In recent years, researchers have expressed a vested interest in the concepts surrounding flapping wing micro air vehicles (FWMAVs) that are capable of both range and complex maneuvering. Most research in this arena has found itself concentrated on topics such as flapping dynamics and the associated fluid-structure interactions inherent in the motion, however there still remains myriad questions concerning the structural qualities intrinsic to the wings themselves. Using nature as the template for design, FWMAV wings were constructed using carbon fiber and Kapton and tested under simplified flapping conditions by analyzing frozen\u27 digital images of the deformed wing by methods of photogrammetry. This flapping motion was achieved via the design and construction of a flapper that emulates several of the kinematic features that can be seen in naturally occurring flyers. The response to this motion was then compared to the inspiring specimen\u27s wings, the North American Hawkmoth (Manduca Sexta), under the same flapping conditions in order to identify some of the key features that nature has deemed necessary for successful flight

    Unassisted Transport of N-acetyl-L-tryptophanamide through Membrane: Experiment and Simulation of Kinetics

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    Cellular transport machinery, such as channels and pumps, is working against the background of unassisted material transport through membranes. The permeation of a blocked tryptophan through a 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) membrane is investigated to probe unassisted or physical transport. The transport rate is measured experimentally and modeled computationally. The time scale measured by Parallel Artificial Membrane Permeation Assay (PAMPA) experiments is ~8 h. Simulations with the Milestoning algorithm suggest Mean First Passage Time (MFPT) of ~4 h and the presence of a large barrier at the center of the bilayer. A similar calculation with the solubility-diffusion model yields MFPT of ~15 min. This permeation rate is nine orders of magnitude slower than the permeation rate of only a tryptophan side chain (computed by us and others). This difference suggests critical dependence of transport time on permeant size and hydrophilicity. Analysis of the simulation results suggests that the permeant partially preserves hydrogen bonding of the peptide backbone to water and lipid molecules even when it is moving closer to the bilayer center. As a consequence, defects of the membrane structure are developed to assist permeation

    MED12 regulates a transcriptional network of calcium-handling genes in the heart

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    The Mediator complex regulates gene transcription by linking basal transcriptional machinery with DNA-bound transcription factors. The activity of the Mediator complex is mainly controlled by a kinase submodule that is composed of 4 proteins, including MED12. Although ubiquitously expressed, Mediator subunits can differentially regulate gene expression in a tissue-specific manner. Here, we report that MED12 is required for normal cardiac function, such that mice with conditional cardiac-specific deletion of MED12 display progressive dilated cardiomyopathy. Loss of MED12 perturbs expression of calcium-handling genes in the heart, consequently altering calcium cycling in cardiomyocytes and disrupting cardiac electrical activity. We identified transcription factors that regulate expression of calcium-handling genes that are downregulated in the heart in the absence of MED12, and we found that MED12 localizes to transcription factor consensus sequences within calcium-handling genes. We showed that MED12 interacts with one such transcription factor, MEF2, in cardiomyocytes and that MED12 and MEF2 co-occupy promoters of calcium-handling genes. Furthermore, we demonstrated that MED12 enhances MEF2 transcriptional activity and that overexpression of both increases expression of calcium-handling genes in cardiomyocytes. Our data support a role for MED12 as a coordinator of transcription through MEF2 and other transcription factors. We conclude that MED12 is a regulator of a network of calcium-handling genes, consequently mediating contractility in the mammalian heart

    Increasing compliance with wearing a medical device in children with autism

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    Health professionals often recommend the use of medical devices to assess the health, monitor the well-being, or improve the quality of life of their patients. Children with autism may present challenges in these situations as their sensory peculiarities may increase refusals to wear such devices. To address this issue, we systematically replicated prior research by examining the effects of differential reinforcement of other behavior (DRO) to increase compliance with wearing a heart rate monitor in 2 children with autism. The intervention increased compliance to 100% for both participants when an edible reinforcer was delivered every 90 s. The results indicate that DRO does not require the implementation of extinction to increase compliance with wearing a medical device. More research is needed to examine whether the reinforcement schedule can be further thinned

    Who are We? Highlighting Nuances in Asian American Experiences in Ecology and Evolutionary Biology

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    As ecologists and evolutionary biologists, it is important to recognize that issues surrounding AAPI do not exist in a vacuum and that these issues affect some of our students and colleagues in and outside of the classroom and lab. Recently, anti-Asian racism has been brought to the forefront of US society. Though media attention has primarily focused on how COVID-19 fears motivated both violent and nonviolent racist incidents against East Asians in 2020 (e.g., Chinese and Taiwanese Americans) (Tessler et al. 2020), attacks on other AAPI groups, such as South and Southeast Asians (e.g., Filipino, Pakistani, and Vietnamese Americans) (Truong 2020, Kuo and Bui 2021), have continued to occur. Thus, there is a need to both discuss and address how issues of racism toward the AAPI community manifest in our own academic communities

    Map-A-Mole: greenspace area influences the presence and abundance of the European mole Talpa europaea in urban habitats

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    The European mole Talpa europaea is common across much of Britain. It has a unique fossorial lifestyle, and evidence of its presence is readily identified through the presence of characteristic molehills. Although molehills are often a common sight in urban greenspaces, moles are remarkably understudied, with very few studies to date exploring the urban ecology of moles. Here, we investigate if factors such as greenspace (largely urban parks and playing fields) area, intensity of management, distance to nearest patch, amount of time the patch had been isolated from other green patches, and the amount of urbanization (constructed surfaces) surrounding the patch, influence the distribution and abundance of urban moles. Mole signs (hills and surface runs) were counted in all discrete urban greenspaces (excluding domestic gardens and one private golf course) within an 89.5 km2 area in the UK town of Reading. We found that 17 out of 59 surveyed sites contained moles, with their presence being recorded in greenspaces with a minimum patch area of approximately 0.1 km2 (10 ha). Where present, the abundance of mole territories in the greenspaces was associated with both the area of greenspace and degree of urbanization within 150 m of the patch boundary. While the former was not surprising, the latter outcome may be a consequence of sites with an increased risk of flooding being home to fewer moles, and the surrounding area is also less likely to be built upon. This case study highlights how choices made in designing urban green infrastructure will determine which species survive in urban areas long into the future

    A Cardiac MicroRNA Governs Systemic Energy Homeostasis by Regulation of MED13

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    SummaryObesity, type 2 diabetes, and heart failure are associated with aberrant cardiac metabolism. We show that the heart regulates systemic energy homeostasis via MED13, a subunit of the Mediator complex, which controls transcription by thyroid hormone and other nuclear hormone receptors. MED13, in turn, is negatively regulated by a heart-specific microRNA, miR-208a. Cardiac-specific overexpression of MED13 or pharmacologic inhibition of miR-208a in mice confers resistance to high-fat diet-induced obesity and improves systemic insulin sensitivity and glucose tolerance. Conversely, genetic deletion of MED13 specifically in cardiomyocytes enhances obesity in response to high-fat diet and exacerbates metabolic syndrome. The metabolic actions of MED13 result from increased energy expenditure and regulation of numerous genes involved in energy balance in the heart. These findings reveal a role of the heart in systemic metabolic control and point to MED13 and miR-208a as potential therapeutic targets for metabolic disorders.PaperCli
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