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- Description:
- Localization of the components of the cardiac conduction system (CCS) is essential for many therapeutic procedures in cardiac surgery and interventional cardiology. While histological studies provided fundamental insights into CCS localization, this information is incomplete and difficult to translate to aid in intraprocedural localization. To advance our understanding of CCS localization, we set out to establish a framework for quantifying nodal region morphology. Using this framework, we quantitatively analyzed the sinoatrial node (SAN) and atrioventricular node (AVN) in ovine with menstrual age ranging from 4.4 to 58.3 months. In particular, we studied the SAN and AVN in relation to the epicardial and endocardial surfaces, respectively. Using anatomical landmarks, we excised the nodes and adjacent tissues, sectioned those at a thickness of 4 µm at 100 µm intervals, and applied Masson’s trichrome stain to the sections. These sections were then imaged, segmented to identify nodal tissue, and analyzed to quantify nodal depth and superficial tissue composition. The minimal SAN depth ranged between 20 and 926 µm. AVN minimal depth ranged between 59 and 1192 µm in the AVN extension region, 49 and 980 µm for the compact node, and 148 and 888 µm for the transition to His Bundle region. Using a logarithmic regression model, we found that minimal depth increased logarithmically with age for the AVN (R2=0.818, P=0.002). Also, the myocardial overlay of the AVN was heterogeneous within different regions and decreased with increasing age. Age associated alterations of SAN minimal depth were insignificant. Our study presents examples of characteristic tissue patterns superficial to the AVN and within the SAN. We suggest that the presented framework provides quantitative information for CCS localization. Our studies indicate that procedural methods and localization approaches in regions near the AVN should account for the age of patients in cardiac surgery and interventional cardiology.
- Subject:
- cardiology and physiology
- Creator:
- Frank Sachse, Brian K. Cottle, and Jordan Johnson
- Owner:
- Frank Sachse
- Language:
- English
- Date Uploaded:
- 11/13/2019
- Date Modified:
- 05/17/2023
- Date Created:
- 2018
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/doi:10.7278/S50D-546S-4RVW
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- Creator:
- Chen, Jiahui , Breen, Joe, Van der Merwe, Jacobus, and Phillips, Jeff M.
- Owner:
- Jiahui Chen
- Date Uploaded:
- 09/04/2020
- Date Modified:
- 09/04/2020
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- Description:
- We apply Bayesian inference to instrument calibration and experimental-data uncertainty analysis for the specific application of measuring radiative intensity with a narrow-angle radiometer. We develop a physics-based instrument model that describes temporally varying radiative intensity, the indirectly measured quantity of interest, as a function of scenario and model parameters. We identify a set of five uncertain parameters, find their probability distributions (the posterior or inverse problem) given the calibration data by applying Bayes’ Theorem, and employ a local linearization to marginalize the nuisance parameters resulting from errors-in-variables. We then apply the instrument model to a new scenario that is the intended use of the instrument, a 1.5 MW coal-fired furnace. Unlike standard error propagation, this Bayesian method infers values for the five uncertain parameters by sampling from the posterior distribution and then computing the intensity with quantifiable uncertainty at the point of a new, in-situ furnace measurement (the posterior predictive or forward problem). Given the instrument-model context of this analysis, the propagated uncertainty provides a significant proportion of the measurement error for each in-situ furnace measurement. With this approach, we produce uncertainties at each temporal measurement of the radiative intensity in the furnace, successfully identifying temporal variations that were otherwise indistinguishable from measurement uncertainty.
- Subject:
- Validation and Simulation
- Creator:
- Scheib, Kaitlyn, Spinti, Jennifer P., Smith, Sean T., Harding, N. Stanley, Smith, Philip J., and Draper, Teri S.
- Owner:
- Philip Smith
- Based Near Label Tesim:
- Salt Lake City, Utah, United States
- Language:
- English
- Date Uploaded:
- 12/01/2020
- Date Modified:
- 01/28/2022
- Date Created:
- November 2020
- Resource Type:
- Software or Program Code
- Identifier:
- https://doi.org/10.7278/S50D6AFQ84VP
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- Description:
- Micrometer-scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial alteration of oceanic basalt in a low temperature hydrothermal system. An integrative investigative approach uses synchrotron source X-ray microdiffraction (µXRD), microfluoresence (µXRF), micro-computed tomography (µCT), and scanning transmission electron microscopy (S/TEM) coupled with Raman spectroscopy to create finely resolved spatial frameworks that record a continuum of alteration in glass and olivine. Micro-analytical maps of vesicular and fractured lapilli in specimens from 157.1, 137.9, and 102.6 m depth, and borehole temperatures of 83, 93.9 and 141.3 °C measured in 1980, respectively, describe the production of nanocrystalline clay mineral, zeolites, and Al-tobermorite in diverse microenvironments. Irregular alteration fronts at 157.1 m depth resemble microchannels associated with biological activity in older basalts. By contrast, linear microstructures with little resemblance to previously described alteration features have nanocrystalline clay mineral (nontronite) and zeolite (amicite) texture. The crystallographic preferred orientation rotates around an axis parallel to the linear feature. Raman spectra indicating degraded and poorly-ordered carbonaceous matter of possible biological origin are associated with nanocrystalline clay mineral in a crystallographically-oriented linear microstructure in altered olivine at 102.6 m and with sub-circular nanoscale cavities in altered glass at 137.9 m depth. Although evidence for biotic processes is inconclusive, the integrated analyses describe the complex organization of previously unrecognized mineral texture in very young basalt. They provide a foundational mineralogical reference for longitudinal, time-lapse characterizations of palagonitized basalt in oceanic environments.
- Creator:
- Couper, Samantha, Parkinson, Dula, Miyagi, Lowell M. , Czabaj, Michael W., Stan, Camelia V. , Moore, James G. , Ivarsson, Magnus, Jackson, Marie D., and Tamura, Nobumichi
- Owner:
- BRIAN MCBRIDE
- Based Near Label Tesim:
- Surtsey, South, Iceland
- Language:
- English
- Date Uploaded:
- 07/11/2019
- Date Modified:
- 03/01/2022
- Date Created:
- 2016-2019
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50D-VJND-8V00
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- Description:
- Light-scattering spectroscopy (LSS) is an established optical approach for nondestructive characterization of biological tissues. Here, we investigated the capabilities of LSS and convolutional neural networks (CNNs) to quantitatively characterize the composition and arrangement of cardiac tissues. We assembled tissue constructs from 200 μm thick sections of fixed myocardium and aortic wall. Thickness of the tissue constructs was similar to the thickness of atrial free wall. In the assembled constructs, the aortic sections represented fibrotic tissue and the depth, volume fraction, and arrangement of these fibrotic insets were varied. We gathered spectra with wavelengths from 500-1100 nm from the constructs at multiple locations relative to a light source. We used single and combinations of two spectra for training of CNNs. With independently measured spectra, we assessed the accuracy of the trained CNNs for classification of tissue constructs from single spectra and combined spectra. In general, classification accuracy with single spectra was smaller than with combined spectra. Combined spectra including spectra from fibers distal from the illumination fiber typically yielded a higher accuracy than proximal single collection fibers. Maximal classification accuracy of depth detection, volume fraction and permutated arrangements was (mean±stddev) 88.97±2.49%, 76.33±1.51% and 84.25±1.88%, respectively. Our studies demonstrate the reliability of quantitative characterization of tissue composition and arrangements using a combination of LSS and CNNs. Potential clinical applications of the developed approach include intraoperative quantification and mapping of atrial fibrosis as well as assessment of ablation lesions.
- Subject:
- cardiology
- Creator:
- Hitchcock, Robert W., Sachse, Frank B., Cottle, Brian K., Kelson, Bailey E.B., and Knighton, Nathan J.
- Owner:
- Frank Sachse
- Based Near Label Tesim:
- Salt Lake City, Utah, United States
- Language:
- English
- Date Uploaded:
- 01/09/2020
- Date Modified:
- 01/22/2022
- Date Created:
- 20190101 to 20190208 and 20200721 to 20200807
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50D-3Q4J-SC4Y
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- Description:
- Subglacial water pressures influence groundwater conditions in proximal alpine valley rock slopes, varying with glacier advance and retreat in parallel with changing ice thickness. Fluctuating groundwater pressures in turn increase or reduce effective joint normal stresses, affecting the yield strength of discontinuities. Here we extend simplified assumptions of glacial debuttressing to investigate how glacier loading cycles together with changing groundwater pressures generate rock slope damage and prepare future slope instabilities. Using hydromechanical coupled numerical models closely based on the Aletsch Glacier valley in Switzerland, we simulate Late Pleistocene and Holocene glacier loading cycles including long-term and annual groundwater fluctuations. Measurements of transient subglacial water pressures from ice boreholes in the Aletsch Glacier ablation area, as well as continuous monitoring of bedrock deformation from permanent GNSS stations helps verify our model assumptions. While purely mechanical glacier loading cycles create only limited rock slope damage in our models, introducing a fluctuating groundwater table generates substantial new fracturing. Superposed annual groundwater cycles increase predicted damage. The cumulative effects are capable of destabilizing the eastern valley flank of our model in toppling-mode failure, similar to field observations of active landslide geometry and kinematics. We find that hydromechanical fatigue is most effective acting in combination with long-term loading and unloading of the slope during glacial cycles. Our results demonstrate that hydromechanical stresses associated with glacial cycles are capable of generating substantial rock slope damage and represent a key preparatory factor for paraglacial slope instabilities.
- Subject:
- Geology
- Creator:
- Moore, Jeffrey, Loew, Simon, Limpach, Philippe, Gischig, Valentin, Grämiger, Lorenz, and Funk, Martin
- Owner:
- Jeff Moore
- Based Near Label Tesim:
- Aletsch Glacier, Valais, Switzerland
- Language:
- English
- Date Uploaded:
- 01/03/2020
- Date Modified:
- 12/09/2021
- Date Created:
- Borehole P1 20130712 09:28:09 to 20140808 09:11:14 and Borehole P2 20130716 05:00:03 to 20140808 22:10:44
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50D-A50H-3TE4
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- Description:
- Future projections suggest an increase in drought globally with climate change. Current vegetation models typically regulate the plant photosynthetic response to soil moisture stress through an empirical function, rather than a mechanistic response where plant water potentials respond to changes in soil water. This representation of soil moisture stress may introduce significant uncertainty into projections for the terrestrial carbon cycle. We examined the use of the soil moisture limitation function in historical and future emissions scenarios in nine Earth system models. We found that soil moisture-limited productivity across models represented a large and uncertain component of the simulated carbon cycle, comparable to 3-286% of current global productivity. Approximately 40-80% of the intermodel variability was due to the functional form of the limitation equation alone. Our results highlight the importance of implementing mechanistic water limitation schemes in models and illuminate several avenues for improving projections of the land carbon sink.
- Creator:
- Medvigy, David, Trugman, Anna T., Mankin, Justin S., and Anderegg, William R.L.
- Owner:
- BRIAN MCBRIDE
- Language:
- English
- Date Uploaded:
- 07/11/2019
- Date Modified:
- 12/09/2021
- Date Created:
- Spring 2016
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S5707ZMS
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- Creator:
- Bromley, Benjamin C. and Kenyon, Scott J.
- Depositor:
- BRIAN MCBRIDE
- Owner:
- BENJAMIN BROMLEY
- Language:
- English
- Date Uploaded:
- 07/11/2019
- Date Modified:
- 12/09/2021
- Date Created:
- 20180515-20181214
- Resource Type:
- Software or Program Code and Dataset
- Identifier:
- https://doi.org/10.7278/s50d-w273-1gg0
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- Creator:
- Bromley, Benjamin and Kenyon, Scott
- Owner:
- BENJAMIN BROMLEY
- Language:
- English
- Date Uploaded:
- 07/26/2019
- Date Modified:
- 12/09/2021
- Resource Type:
- Dataset and Software or Program Code
- Identifier:
- https://doi.org/10.7278/S50D-EFCY-ZC00