273 research outputs found

    The impact of compressive force magnitude on the in vitro neutral zone range and passive stiffness during a flexion–extension range of motion test

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    Noguchi, M., Gooyers, C. E., Holmes, M. W. R., & Callaghan, J. P. (2015). The impact of compressive force magnitude on the in vitro neutral zone range and passive stiffness during a flexion-extension range of motion test. Cogent Engineering, 2(1). https://doi.org/10.1080/23311916.2015.1014253The objective of this work was to examine the influence of compressive force magnitude on a functional spinal unit’s (FSU) flexion–extension neutral zone measured during pure moment (PM) tests. Each porcine cervical FSU received four repeats of a PM test with 10, 300, 900 and 1,800 N of compressive force, in a randomized order. Increasing the magnitude of compression significantly decreased the neutral zone range (p < 0.001), while increasing passive stiffness (p < 0.001). The flexion limit at 10 N was significantly lower (p < 0.05) than the other loading conditions. Reporting the compressive force magnitude is important when posture is a standardized experimental factor considered in the design of in vitro spine biomechanics studies.The authors acknowledge partial funding from the Natural Science and Engineering Research Council of Canada (NSERC). Dr. Jack Callaghan is supported by the Canada Research Chair in Spine Biomechanics and Injury Preventio

    Spatial representation of temporal information through spike timing dependent plasticity

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    We suggest a mechanism based on spike time dependent plasticity (STDP) of synapses to store, retrieve and predict temporal sequences. The mechanism is demonstrated in a model system of simplified integrate-and-fire type neurons densely connected by STDP synapses. All synapses are modified according to the so-called normal STDP rule observed in various real biological synapses. After conditioning through repeated input of a limited number of of temporal sequences the system is able to complete the temporal sequence upon receiving the input of a fraction of them. This is an example of effective unsupervised learning in an biologically realistic system. We investigate the dependence of learning success on entrainment time, system size and presence of noise. Possible applications include learning of motor sequences, recognition and prediction of temporal sensory information in the visual as well as the auditory system and late processing in the olfactory system of insects.Comment: 13 pages, 14 figures, completely revised and augmented versio

    The electronic structure of poly(pyridine-2,5-diyl) investigated by soft x-ray absorption and emission spectroscopies

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    The electronic structure of the poly-pyridine conjugated polymer has been investigated by resonant and nonresonant inelastic X-ray scattering and X-ray absorption spectroscopies using synchrotron radiation. The measurements were made for both the carbon and nitrogen contents of the polymer. The analysis of the spectra has been carried out in comparison with molecular orbital calculations taking the repeat-unit cell as a model molecule of the polymer chain. The simulations indicate no significant differences in the absorption and in the non-resonant X-ray scattering spectra for the different isomeric geometries, while some isomeric dependence of the resonant spectra is predicted. The resonant emission spectra show depletion of the {\pi} electron bands in line with symmetry selection and momentum conservation rules. The effect is most vizual for the carbon spectra; the nitrogen spectra are dominated by lone pair n orbital emission of {\sigma} symmetry and are less frequency dependent.Comment: 11 pages, 7 figures, 1 table, http://www.sciencedirect.com/science/article/pii/S030101049800262

    Weber and church governance: religious practice and economic activity

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    The debate about the relationship between religion and economic activity in the wake of Weber has been cast largely in terms of belief and values. This article suggests an alternative focus on practice. It argues that taken for granted practices of church governance formed to-hand resources for the organization of economic activity. The argument is developed through an examination of the historical development of church governance practices in the Presbyterian Church of Scotland, with particular emphasis on the way in which theological belief gave rise to practices of accountability and record keeping. In turn such practices contributed to a ‘culture of organization’ which had implications for economic activity. A focus on governance practices can help to illuminate enduring patterns of difference in the organization of economic activity

    Novel inhibition of carbonic anhydrase isozymes I, II and III by carbamoyl phosphate

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    Carbamoyl phosphate has been shown to inhibit carbonic anhydrase (CA) isozymes CA I, CA II and CA III. This physiologically important molecule is the most potent, naturally occurring inhibitor of carbonic anhydrase yet found. It is also unique, among carbonic anhydrase inhibitors discovered hitherto, in that it inhibits the 3 isozymes with equal effect, despite their strikingly different properties. The results imply the participation of carbonic anhydrase in the regulation of substrate availability for the urea cycle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24933/1/0000360.pd

    Irish cardiac society - Proceedings of annual general meeting held 20th & 21st November 1992 in Dublin Castle

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    Cost-Effectiveness Modeling of Surgery Plus Adjuvant Endocrine Therapy Versus Primary Endocrine Therapy Alone in UK Women Aged 70 and Over With Early Breast Cancer

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    Objectives: Approximately 20% of UK women aged 70+ with early breast cancer receive primary endocrine therapy (PET) instead of surgery. PET reduces surgical morbidity but with some survival decrement. To complement and utilize a treatment dependent prognostic model, we investigated the cost-effectiveness of surgery plus adjuvant therapies versus PET for women with varying health and fitness, identifying subgroups for which each treatment is cost-effective. Methods: Survival outcomes from a statistical model, and published data on recurrence, were combined with data from a large, multicenter, prospective cohort study of over 3400 UK women aged 70+ with early breast cancer and median 52-month follow-up, to populate a probabilistic economic model. This model evaluated the cost-effectiveness of surgery plus adjuvant therapies relative to PET for 24 illustrative subgroups: Age {70, 80, 90} × Nodal status {FALSE (F), TRUE (T)} × Comorbidity score {0, 1, 2, 3+}. Results: For a 70-year-old with no lymph node involvement and no comorbidities (70, F, 0), surgery plus adjuvant therapies was cheaper and more effective than PET. For other subgroups, surgery plus adjuvant therapies was more effective but more expensive. Surgery plus adjuvant therapies was not cost-effective for 4 of the 24 subgroups: (90, F, 2), (90, F, 3), (90, T, 2), (90, T, 3). Conclusion: From a UK perspective, surgery plus adjuvant therapies is clinically effective and cost-effective for most women aged 70+ with early breast cancer. Cost-effectiveness reduces with age and comorbidities, and for women over 90 with multiple comorbidities, there is little cost benefit and a negative impact on quality of life
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