scholarly journals Controls on mud distribution and architecture along the fluvial-to-marine transition

2020 ◽  
Author(s):  
Daniel Parsons ◽  
Wietse Van de Lageweg ◽  
Lisanne Braat ◽  
Maarten Kleinhans
Keyword(s):  
River Flow ◽  
Three Dimensional ◽  
Quantitative Information ◽  
System Stability ◽  
Relative Importance ◽  
Coastal System ◽  
Fluvial Processes ◽  
Coastal Systems ◽  
Sedimentary Architecture ◽  
Sedimentary Fill

<p>The interaction of marine (tides and waves) and fluvial processes determines the sedimentary fill of coastal systems in the fluvial-to-marine (FTM) transition zone. Despite frequent recognition of tidal and wave influence in modern and ancient systems, our understanding of the relative importance of marine processes and their impact on mud deposition, coastal system stability and sedimentary architecture is limited. This study combined subsurface field observations and numerical simulations to investigate the relative importance of river flow, tides, waves, and mud input in governing the sedimentary fill in funnel-shaped basins along the FTM transition. Model simulations show a self-forming bar-built estuary with dynamic channels and sandy bars flanked by mud flats, which is in agreement with trends observed in nature. From three-dimensional virtual sedimentary successions, statistical tendencies for mud distribution and thickness were derived for the spectrum of marine and fluvial processes, and these values provide quantitative information on the net-to-gross ratio and mud architecture. The relative influence of marine and fluvial processes leads to a predictable facies organization and architecture, with muddier and more heterogeneous sediments toward the flanks. For the first time, our simulations allow the sedimentary fill in basins along the FTM transition to be related explicitly to hydrodynamic conditions, providing new insights into the morphosedimentary evolution of coastal systems, with implications for system stability in the modern and sequence stratigraphy preserved in the ancient.</p>

scholarly journals Improvement on Permeability of Cyclic Peptide/Peptidomimetic: Backbone N-Methylation as A Useful Tool

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 311
Author(s):  
Yang Li ◽  
Wang Li ◽  
Zhengshuang Xu
Keyword(s):  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Three Dimensional ◽  
Conformational Space ◽  
Cell Permeability ◽  
Relative Importance ◽  
Intrinsic Properties ◽  
Surface Areas ◽  
Synthetic Methodologies ◽  
Three Dimensional Configuration

Peptides have a three-dimensional configuration that can adopt particular conformations for binding to proteins, which are well suited to interact with larger contact surface areas on target proteins. However, low cell permeability is a major challenge in the development of peptide-related drugs. In recent years, backbone N-methylation has been a useful tool for manipulating the permeability of cyclic peptides/peptidomimetics. Backbone N-methylation permits the adjustment of molecule’s conformational space. Several pathways are involved in the drug absorption pathway; the relative importance of each N-methylation to total permeation is likely to differ with intrinsic properties of cyclic peptide/peptidomimetic. Recent studies on the permeability of cyclic peptides/peptidomimetics using the backbone N-methylation strategy and synthetic methodologies will be presented in this review.

scholarly journals A Voxel-Map Quantitative Analysis Approach for Atherosclerotic Noncalcified Plaques of the Coronary Artery Tree

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Li ◽  
Wei Chen ◽  
Kaijun Liu ◽  
Yi Wu ◽  
Yonglin Chen ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Three Dimensional ◽  
Coronary Intervention ◽  
Quantitative Information ◽  
Atherosclerotic Plaques ◽  
Anatomical Location ◽  
Contrast Enhanced ◽  
Percutaneous Coronary ◽  
Map Analysis ◽  
Coronary Artery Tree

Noncalcified plaques (NCPs) are associated with the presence of lipid-core plaques that are prone to rupture. Thus, it is important to detect and monitor the development of NCPs. Contrast-enhanced coronary Computed Tomography Angiography (CTA) is a potential imaging technique to identify atherosclerotic plaques in the whole coronary tree, but it fails to provide information about vessel walls. In order to overcome the limitations of coronary CTA and provide more meaningful quantitative information for percutaneous coronary intervention (PCI), we proposed a Voxel-Map based on mathematical morphology to quantitatively analyze the noncalcified plaques on a three-dimensional coronary artery wall model (3D-CAWM). This approach is a combination of Voxel-Map analysis techniques, plaque locating, and anatomical location related labeling, which show more detailed and comprehensive coronary tree wall visualization.

Automated Pancreas Segmentation And Volumetry Using Deep Neural Network On Computed Tomography

2021 ◽  
Author(s):  
Sang-Heon Lim ◽  
Young Jae Kim ◽  
Yeon-Ho Park ◽  
Doojin Kim ◽  
Kwang Gi Kim ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Deep Learning ◽  
Automatic Segmentation ◽  
External Validation ◽  
Three Dimensional ◽  
Semantic Segmentation ◽  
Quantitative Information ◽  
Similarity Coefficients ◽  
Internal Validation ◽  
Pancreas Segmentation

Abstract Pancreas segmentation is necessary for observing lesions, analyzing anatomical structures, and predicting patient prognosis. Therefore, various studies have designed segmentation models based on convolutional neural networks for pancreas segmentation. However, the deep learning approach is limited by a lack of data, and studies conducted on a large computed tomography dataset are scarce. Therefore, this study aims to perform deep-learning-based semantic segmentation on 1,006 participants and evaluate the automatic segmentation performance of the pancreas via four individual three-dimensional segmentation networks. In this study, we performed internal validation with 1,006 patients and external validation using the Cancer Imaging Archive (TCIA) pancreas dataset. We obtained mean precision, recall, and dice similarity coefficients of 0.869, 0.842, and 0.842, respectively, for internal validation via a relevant approach among the four deep learning networks. Using the external dataset, the deep learning network achieved mean precision, recall, and dice similarity coefficients of 0.779, 0.749, and 0.735, respectively. We expect that generalized deep-learning-based systems can assist clinical decisions by providing accurate pancreatic segmentation and quantitative information of the pancreas for abdominal computed tomography.

Three-Dimensional Sedimentary Architecture of a Large, Mid-Channel Sand Braid Bar, Jamuna River, Bangladesh

2003 ◽  
Vol 73 (4) ◽  
pp. 516-530 ◽  
Author(s):  
J. L. Best ◽  
P. J. Ashworth ◽  
C. S. Bristow ◽  
J. Roden
Keyword(s):  
Three Dimensional ◽  
Sedimentary Architecture

Transmission Electron Diffraction Techniques for Nm Scale Strain Measurement in Semiconductors

1995 ◽  
Vol 405 ◽  
Author(s):  
J. Vanhellemont ◽  
K. G. F. Janssens ◽  
S. Frabboni ◽  
P. Smeys ◽  
R. Balboni ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Large Angle ◽  
Three Dimensional ◽  
Local Strain ◽  
Quantitative Information ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Convergent Beam

AbstractAn overview is given of transmission electron microscopy techniques to address strain with nm scale spatial resolution. In particular the possibilities and limitations of (large angle) convergent beam electron diffraction ((LA)CBED) and electron diffraction contrast imaging (EDCI) techniques are discussed in detail. It will be shown by a few case studies that unique and quantitative information on local strain distributions can be obtained by the combined use of both (LA)CBED and EDCI in correlation with three dimensional finite element simulations of the strain distributions in the thinned specimen.

Computer Simulation of Stepping in the Hind Legs of the Cat: An Examination of Mechanisms Regulating the Stance-to-Swing Transition

2005 ◽  
Vol 94 (6) ◽  
pp. 4256-4268 ◽  
Author(s):  
Örjan Ekeberg ◽  
Keir Pearson
Keyword(s):  
Computer Simulation ◽  
Three Dimensional ◽  
Swing Phase ◽  
Relative Importance ◽  
Mutual Inhibition ◽  
Small Perturbations ◽  
Position Signal ◽  
Extensor Muscles ◽  
Force Signal ◽  
Hip Extension

Physiological studies in walking cats have indicated that two sensory signals are involved in terminating stance in the hind legs: one related to unloading of the leg and the other to hip extension. To study the relative importance of these two signals, we developed a three-dimensional computer simulation of the cat hind legs in which the timing of the swing-to-stance transition was controlled by signals related to the force in ankle extensor muscles, the angle at the hip joint, or a combination of both. Even in the absence of direct coupling between the controllers for each leg, stable stepping was easily obtained using either a combination of ankle force and hip position signals or the ankle force signal alone. Stable walking did not occur when the hip position signal was used alone. Coupling the two controllers by mutual inhibition restored stability, but it did not restore the correct timing of stepping of the two hind legs. Small perturbations applied during the swing phase altered the movement of the contralateral leg in a manner that tended to maintain alternating stepping when the ankle force signal was included but tended to shift coordination away from alternating when the hip position signal was used alone. We conclude that coordination of stepping of the hind legs depends critically on load-sensitive signals from each leg and that mechanical linkages between the legs, mediated by these signals, play a significant role in establishing the alternating gait.

scholarly journals Stereological assessment of mouse lung parenchyma via nondestructive, multiscale micro-CT imaging validated by light microscopic histology

2013 ◽  
Vol 114 (6) ◽  
pp. 716-724 ◽  
Author(s):  
Dragoş M. Vasilescu ◽  
Christine Klinge ◽  
Lars Knudsen ◽  
Leilei Yin ◽  
Ge Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Lung Parenchyma ◽  
Quantitative Information ◽  
Mouse Lung ◽  
Imaging Method ◽  
Micro Computed Tomography ◽  
Lung Structure ◽  
Internal Structures ◽  
Multiple Resolutions ◽  
Conventional Histology

Quantitative assessment of the lung microstructure using standard stereological methods such as volume fractions of tissue, alveolar surface area, or number of alveoli, are essential for understanding the state of normal and diseased lung. These measures are traditionally obtained from histological sections of the lung tissue, a process that ultimately destroys the three-dimensional (3-D) anatomy of the tissue. In comparison, a novel X-ray-based imaging method that allows nondestructive sectioning and imaging of fixed lungs at multiple resolutions can overcome this limitation. Scanning of the whole lung at high resolution and subsequent regional sampling at ultrahigh resolution without physically dissecting the organ allows the application of design-based stereology for assessment of the whole lung structure. Here we validate multiple stereological estimates performed on micro–computed tomography (μCT) images by comparing them with those obtained via conventional histology on the same mouse lungs. We explore and discuss the potentials and limitations of the two approaches. Histological examination offers higher resolution and the qualitative differentiation of tissues by staining, but ultimately loses 3-D tissue relationships, whereas μCT allows for the integration of morphometric data with the spatial complexity of lung structure. However, μCT has limited resolution satisfactory for the sterological estimates presented in this study but not for differentiation of tissues. We conclude that introducing stereological methods in μCT studies adds value by providing quantitative information on internal structures while not curtailing more complex approaches to the study of lung architecture in the context of physiological or pathological studies.

Synthesis, structural characterization and computational studies of catena-poly[chlorido[μ3-(pyridin-1-ium-3-yl)phosphonato-κ3 O:O′:O′′]zinc(II)]

2017 ◽  
Vol 73 (5) ◽  
pp. 363-368
Author(s):  
Magdalena Wilk-Kozubek ◽  
Katarzyna N. Jarzembska ◽  
Jan Janczak ◽  
Veneta Videnova-Adrabinska
Keyword(s):  
Hydrogen Bonds ◽  
Metal Ion ◽  
Three Dimensional ◽  
Quantitative Information ◽  
Polymeric Chain ◽  
Supramolecular Network ◽  
Monoclinic Space Group ◽  
Face To Face ◽  
Counter Ions ◽  
Phosphonate Ligands

Coordination polymers are constructed from two basic components, namely metal ions, or metal-ion clusters, and bridging organic ligands. Their structures may also contain other auxiliary components, such as blocking ligands, counter-ions and nonbonding guest or template molecules. The choice or design of a suitable linker is essential. The new title zinc(II) coordination polymer, [Zn(C5H5NO3P)Cl] n , has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction and vibrational spectroscopy (FT–IR and FT–Raman). Additionally, computational methods have been applied to derive quantitative information about interactions present in the solid state. The compound crystallizes in the monoclinic space group C2/c. The four-coordinated ZnII cation is in a distorted tetrahedral environment, formed by three phosphonate O atoms from three different (pyridin-1-ium-3-yl)phosphonate ligands and one chloride anion. The ZnII ions are extended by phosphonate ligands to generate a ladder chain along the [001] direction. Adjacent ladders are held together via N—H...O hydrogen bonds and offset face-to-face π–π stacking interactions, forming a three-dimensional supramolecular network with channels. As calculated, the interaction energy between the neighbouring ladders is −115.2 kJ mol−1. In turn, the cohesive energy evaluated per asymmetric unit-equivalent fragment of a polymeric chain in the crystal structure is −205.4 kJ mol−1. This latter value reflects the numerous hydrogen bonds stabilizing the three-dimensional packing of the coordination chains.

Geometric attributes of reservoir elements in a modern, low accomodation, tide-dominated delta

2012 ◽  
Vol 52 (1) ◽  
pp. 483 ◽  
Author(s):  
Rachel Nanson ◽  
Bruce Ainsworth ◽  
Boyan Vakarelov ◽  
Andrew Fernie ◽  
Thomas Massey
Keyword(s):  
Depositional Environments ◽  
Fluvial System ◽  
Coastal System ◽  
Process Systems ◽  
Delta Plain ◽  
Fluvial Processes ◽  
Fluvial Reservoir ◽  
Reservoir Models ◽  
Parallel Features ◽  
Depositional Elements

The influence of wave, tide and fluvial processes on shorelines varies considerably in and between coastal systems; this can result in the development of architecturally complex, mixed-process systems. Of these, tide-dominated systems produce some of the most heterogeneous deposits. The arrangement of reservoir elements generated by wave and fluvial processes in such tide-dominated systems can be, to some degree, systematic and predictable. This research details a modern, tide-dominated, fluvial-influenced, wave-affected coastal system. It presents geometric attributes for reservoir elements that can be used to improve the construction of 3D reservoir models of these depositional environments. The Mitchell River is the largest fluvial system, discharging into the low accommodation setting of the Gulf of Carpentaria. Its Holocene delta extends to more than 500 km2. Eleven types of depositional elements (n = 3,100) were mapped across the delta plain: 286 km2 of tidal, 133 km2 of fluvial and 101 km2 of wave elements make up the delta surface. Fluvially and wave-formed reservoir elements form systematic arrangements across the system. More than 75% of wave elements are aligned inside 45° of the shoreline and these are generally crescentic (asymmetric) or linear in shape. Fluvial elements are aligned either perpendicular to the shoreline, or alongshore, because they are trapped behind wave-formed, shore parallel features. Separate wave and fluvial reservoir element datasets demonstrate convincing, though distinctly different, length-to-width relationships; wave-formed elements are much longer than fluvial-formed elements, relative to their widths. Despite pronounced heterogeneity in the distribution of these depositional elements across the delta surface, these relationships suggest their distribution is, to some degree, predictable. Analysis of the connectivity of adjacent sandbody elements suggests the largest connected sandbody is significant and extends to more than 90 km2.

Production and Development of Secondary Flows and Losses Within a Three Dimensional Turbine Stator Cascade

1985 ◽  
Author(s):  
A. Yamamoto ◽  
R. Yanagi
Keyword(s):  
Three Dimensional ◽  
Quantitative Information ◽  
Secondary Flows ◽  
Suction Surface ◽  
Trailing Edge ◽  
Loss Mechanism ◽  
Flow Measurements ◽  
Aerodynamic Loss ◽  
Vortical Flows ◽  
Turbine Stator

Using five-hole pitot tubes, detailed flow measurements were made before, within and after a low-speed three-dimensional turbine stator blade row to obtain quantitative information on the aerodynamic loss mechanism. Qualitative flow visualization tests and endwall static pressure measurements were also made. An analysis of the tests revealed that many vortical flows promote loss generation. Within a large part of the cascade, a major loss process could be explained simply as the migration of boundary layer low energy fluids from surrounding walls (endwalls and blade surfaces) to the blade suction surface near the trailing edge. On the other hand, complexity exists after the cascade and in the vortical flows near the trailing edge. The strong trailing shedding vortices affect upstream flow fields within the cascade. Detailed flow surveys within the cascade under the effects of blade tip leakage flows are also included.

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