2,417 research outputs found

    Dynamics of the Lever-Arm Swing in Myosin V

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    Lifestyle Medicine Professionals in Training: A Survey of Behaviors, Knowledge and Needs

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    Background/Purpose: It is well known that healthy lifestyle habits can influence chronic disease risk and outcomes. The effective practice of Lifestyle Medicine (LM), however, goes beyond general recommendations and has been encapsulated in well-defined clinical competencies. While it has been documented that graduating medical students feel inadequately prepared to counsel patients in nutrition and exercise, the purpose of this study is to explore the perceptions and experiences of Lifestyle Medicine in a group of interdisciplinary healthcare trainees. Methods: A pilot survey of trainees at the 2015 Annual American College of Lifestyle Medicine (ACLM) Conference assessed perspectives on the inclusion of nutrition and exercise in their educational curricula, knowledge of core LM competencies and personal health habits. Results: Of the 37 trainees registered, 22 surveys were completed. Twenty-six percent indicated they were exposed to courses in exercise; sixty-five percent reported having a nutrition block and fifty percent received instruction on counseling about LM behaviors. Relative importance using Likert scale (1-not important, 5-very important) ascribed similar levels of importance to exercise (4.44), nutrition (4.31), and behavioral counseling (4.58) training. Ninety-five percent reported personal engagement in physical activity, however only forty-two percent were familiar with the Lifestyle Medicine core competencies. Ninety-four percent indicated that the current medical model was insufficient in educating trainees to address lifestyle related diseases. Conclusion: In a select multidisciplinary sample of trainees, there is recognition of the importance of Lifestyle Medicine training. Although trainees surveyed practice healthful behaviors, the majority were not familiar with core Lifestyle Medicine competences and express strong interest in increased Lifestyle Medicine in their training experience

    Speckle Space-Time Covariance in High-Contrast Imaging

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    We introduce a new framework for point-spread function (PSF) subtraction based on the spatio-temporal variation of speckle noise in high-contrast imaging data where the sampling timescale is faster than the speckle evolution timescale. One way that space-time covariance arises in the pupil is as atmospheric layers translate across the telescope aperture and create small, time-varying perturbations in the phase of the incoming wavefront. The propagation of this field to the focal plane preserves some of that space-time covariance. To utilize this covariance, our new approach uses a Karhunen-Lo\'eve transform on an image sequence, as opposed to a set of single reference images as in previous applications of Karhunen-Lo\'eve Image Processing (KLIP) for high-contrast imaging. With the recent development of photon-counting detectors, such as microwave kinetic inductance detectors (MKIDs), this technique now has the potential to improve contrast when used as a post-processing step. Preliminary testing on simulated data shows this technique can improve contrast by at least 10-20% from the original image, with significant potential for further improvement. For certain choices of parameters, this algorithm may provide larger contrast gains than spatial-only KLIP.Comment: Accepted to A

    Measurement of Calcium Dissociation Rates from Troponin C in Rigor Skeletal Myofibrils

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    Ca2+ dissociation from the regulatory domain of troponin C may influence the rate of striated muscle relaxation. However, Ca2+ dissociation from troponin C has not been measured within the geometric and stoichiometric constraints of the muscle fiber. Here we report the rates of Ca2+ dissociation from the N-terminal regulatory and C-terminal structural domains of fluorescent troponin C constructs reconstituted into rabbit rigor psoas myofibrils using stopped-flow technology. Chicken skeletal troponin C fluorescently labeled at Cys 101, troponin CIAEDANS, reported Ca2+ dissociation exclusively from the structural domain of troponin C at ∼0.37, 0.06, and 0.07/s in isolation, in the presence of troponin I and in myofibrils at 15°C, respectively. Ca2+ dissociation from the regulatory domain was observed utilizing fluorescently labeled troponin C containing the T54C and C101S mutations. Troponin CMIANST54C,C101S reported Ca2+ dissociation exclusively from the regulatory domain of troponin C at >1000, 8.8, and 15/s in isolation, in the presence of troponin I and in myofibrils at 15°C, respectively. Interestingly, troponin CIAANST54C,C101S reported a biphasic fluorescence change upon Ca2+ dissociation from the N- and C-terminal domains of troponin C with rates that were similar to those reported by troponin CMIANST54C,C101S and troponin CIAEDANS at all levels of the troponin C systems. Furthermore, the rate of Ca2+ dissociation from troponin C in the myofibrils was similar to the rate of Ca2+ dissociation measured from the troponin C-troponin I complexes. Since the rate of Ca2+ dissociation from the regulatory domain of TnC in myofibrils is similar to the rate of skeletal muscle relaxation, Ca2+ dissociation from troponin C may influence relaxation

    Staurosporine Inhibits Frequency-Dependent Myofilament Desensitization in Intact Rabbit Cardiac Trabeculae

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    Myofilament calcium sensitivity decreases with frequency in intact healthy rabbit trabeculae and associates with Troponin I and Myosin light chain-2 phosphorylation. We here tested whether serine-threonine kinase activity is primarily responsible for this frequency-dependent modulations of myofilament calcium sensitivity. Right ventricular trabeculae were isolated from New Zealand White rabbit hearts and iontophoretically loaded with bis-fura-2. Twitch force-calcium relationships and steady state force-calcium relationships were measured at frequencies of 1 and 4 Hz at 37 °C. Staurosporine (100 nM), a nonspecific serine-threonine kinase inhibitor, or vehicle (DMSO) was included in the superfusion solution before and during the contractures. Staurosporine had no frequency-dependent effect on force development, kinetics, calcium transient amplitude, or rate of calcium transient decline. The shift in the pCa50 of the force-calcium relationship was significant from 6.05 ± 0.04 at 1 Hz versus 5.88 ± 0.06 at 4 Hz under control conditions (vehicle, P < 0.001) but not in presence of staurosporine (5.89 ± 0.08 at 1 Hz versus 5.94 ± 0.07 at 4 Hz, P = NS). Phosphoprotein analysis (Pro-Q Diamond stain) confirmed that staurosporine significantly blunted the frequency-dependent phosphorylation at Troponin I and Myosin light chain-2. We conclude that frequency-dependent modulation of calcium sensitivity is mediated through a kinase-specific effect involving phosphorylation of myofilament proteins

    Response rates for mailout survey-driven studies in patients with head and neck cancer

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    Background: Mailout survey studies are becoming more prevalent in the head and neck literature. The objective of this paper is to summarize response rates in patients with head and neck cancer, and to provide recommendations surrounding methodology used to design and implement mailout survey questionnaires. Methods: The results of this paper are from a study assessing the measurement properties of the Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH) in head and neck cancer patients. A modified Dillman tailored design approach was used. Results: The methods used yielded a response rate of 80% with this patient population. Conclusion: This is a considerably higher response rate than other reports in the oncology literature. © 2010 Wiley Periodicals, Inc. Head Neck, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78489/1/21363_ftp.pd

    Morphing Ensemble Kalman Filters

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    A new type of ensemble filter is proposed, which combines an ensemble Kalman filter (EnKF) with the ideas of morphing and registration from image processing. This results in filters suitable for nonlinear problems whose solutions exhibit moving coherent features, such as thin interfaces in wildfire modeling. The ensemble members are represented as the composition of one common state with a spatial transformation, called registration mapping, plus a residual. A fully automatic registration method is used that requires only gridded data, so the features in the model state do not need to be identified by the user. The morphing EnKF operates on a transformed state consisting of the registration mapping and the residual. Essentially, the morphing EnKF uses intermediate states obtained by morphing instead of linear combinations of the states.Comment: 17 pages, 7 figures. Added DDDAS references to the introductio
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