scholarly journals Three-dimensional morphometric analysis of the renal vasculature

2018 ◽  
Vol 314 (5) ◽  
pp. F715-F725 ◽  
Author(s):  
Zohaib Khan ◽  
Jennifer P. Ngo ◽  
Bianca Le ◽  
Roger G. Evans ◽  
James T. Pearson ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Three Dimensional ◽  
Image Resolution ◽  
Rabbit Kidney ◽  
Renal Vasculature ◽  
Automated Method ◽  
Precise Characterization ◽  
Vascular Geometry ◽  
Renal Vascular

Vascular topology and morphology are critical in the regulation of blood flow and the transport of small solutes, including oxygen, carbon dioxide, nitric oxide, and hydrogen sulfide. Renal vascular morphology is particularly challenging, since many arterial walls are partially wrapped by the walls of veins. In the absence of a precise characterization of three-dimensional branching vascular geometry, accurate computational modeling of the intrarenal transport of small diffusible molecules is impossible. An enormous manual effort was required to achieve a relatively precise characterization of rat renal vascular geometry, highlighting the need for an automated method for analysis of branched vasculature morphology to allow characterization of the renal vascular geometry of other species, including humans. We present a semisupervised method for three-dimensional morphometric analysis of renal vasculature images generated by computed tomography. We derive quantitative vascular attributes important to mass transport between arteries, veins, and the renal tissue and present methods for their computation for a three-dimensional vascular geometry. To validate the algorithm, we compare automated vascular estimates with subjective manual measurements for a portion of rabbit kidney. Although increased image resolution can improve outcomes, our results demonstrate that the method can quantify the morphological characteristics of artery-vein pairs, comparing favorably with manual measurements. Similar to the rat, we show that rabbit artery-vein pairs become less intimate along the course of the renal vasculature, but the total wrapped mass transfer coefficient increases and then decreases. This new method will facilitate new quantitative physiological models describing the transport of small molecules within the kidney.

scholarly journals Three-dimensional microstructure and numerical calculation of elastic properties of alpine snow with a focus on weak layers

2014 ◽  
Vol 60 (222) ◽  
pp. 705-713 ◽  
Author(s):  
Berna Köchle ◽  
Martin Schneebeli
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Large Change ◽  
X Ray ◽  
Weak Layer ◽  
Snow Stratigraphy ◽  
Precise Characterization ◽  
Microstructural Variability

AbstractThe microstructure and stratigraphy of a snowpack determine its physical behaviour. Weak layers or weak interfaces buried under a slab are prerequisites for the formation of dry-snow slab avalanches, and a precise characterization of weak layers or interfaces is essential to assess stability. Yet their exact geometry and micromechanical properties are poorly known. We cast weak layers and their adjacent layers in the field during two winters and reconstructed their three-dimensional microstructure using X-ray microcomputer tomography. The high resolution of 10–20 μm allowed us to study snow stratigraphy at the microstructural scale. We quantified the microstructural variability for 32 centimetre-sized layered samples and we calculated Young’s modulus and Poisson’s ratio by tomography-based finite-element simulations. Layers in a sample could therefore be differentiated not only by a change in morphology or microstructure, but also by a change in mechanical properties. We found a logarithmic correlation of Young’s modulus with density for two different density ranges, consistent with previous studies. By calculating the relative microstructural changes within our samples, we showed that a large change could indicate a potential weak layer, but only when the weak layer and both adjacent layers, i.e. the sandwich, were considered.

scholarly journals An Overview on Collagen and Gelatin-Based Cryogels: Fabrication, Classification, Properties and Biomedical Applications

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2299
Author(s):  
Yujing He ◽  
Chunhua Wang ◽  
Chenzhi Wang ◽  
Yuanhang Xiao ◽  
Wei Lin
Keyword(s):  
Cell Culture ◽  
Physicochemical Properties ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Three Dimensional ◽  
Preparation Process ◽  
Precise Characterization ◽  
Gel Forming Ability ◽  
Insight Into

Decades of research into cryogels have resulted in the development of many types of cryogels for various applications. Collagen and gelatin possess nontoxicity, intrinsic gel-forming ability and physicochemical properties, and excellent biocompatibility and biodegradability, making them very desirable candidates for the fabrication of cryogels. Collagen-based cryogels (CBCs) and gelatin-based cryogels (GBCs) have been successfully applied as three-dimensional substrates for cell culture and have shown promise for biomedical use. A key point in the development of CBCs and GBCs is the quantitative and precise characterization of their properties and their correlation with preparation process and parameters, enabling these cryogels to be tuned to match engineering requirements. Great efforts have been devoted to fabricating these types of cryogels and exploring their potential biomedical application. However, to the best of our knowledge, no comprehensive overviews focused on CBCs and GBCs have been reported currently. In this review, we attempt to provide insight into the recent advances on such kinds of cryogels, including their fabrication methods and structural properties, as well as potential biomedical applications.

PD7-04 PRECISE CHARACTERIZATION OF BLADDER NECK INNERVATION WITH THREE-DIMENSIONAL IMAGE RECONSTRUCTION

2015 ◽  
Vol 193 (4S) ◽  
Author(s):  
Kyle Spradling ◽  
Cyrus Khoyilar ◽  
Garen Abedi ◽  
Zhamshid Okhunov ◽  
Michael del Junco ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Bladder Neck ◽  
Three Dimensional ◽  
Dimensional Image ◽  
Precise Characterization

Structural morphology of renal vasculature

2006 ◽  
Vol 291 (1) ◽  
pp. H296-H309 ◽  
Author(s):  
David A. Nordsletten ◽  
Shane Blackett ◽  
Michael D. Bentley ◽  
Erik L. Ritman ◽  
Nicolas P. Smith
Keyword(s):  
Automatic Segmentation ◽  
Three Dimensional ◽  
Convincing Evidence ◽  
Renal Physiology ◽  
Renal Vasculature ◽  
Structural Morphology ◽  
Radial Length ◽  
Renal Vascular ◽  
Vascular Trees ◽  
Arteries And Veins

An automatic segmentation technique has been developed and applied to two renal micro-computer tomography (CT) images. With the use of a 20-μm voxel resolution image, the arterial and venous trees were segmented for the rat renal vasculature, distinguishing resolving vessels down to 30 μm in radius. A higher resolution 4-μm voxel image of a renal vascular subtree, with vessel radial values down to 10 μm, was segmented. Strahler ordering was applied to each subtree using an iterative scheme developed to integrate information from the two segmented models to reconstruct the complete topology of the entire vascular tree. An error analysis of the assigned orders quantified the robustness of the ordering process for the full model. Radial, length, and connectivity data of the complete arterial and venous trees are reported by order. Substantial parallelism is observed between individual arteries and veins, and the ratio of parallel vessel radii is quantified via a power law. A strong correlation with Murray's Law was established, providing convincing evidence of the “minimum work” hypothesis. Results were compared with theoretical branch angle formulations, based on the principles of “minimum shear force,” were inconclusive. Three-dimensional reconstructions of renal vascular trees collected are made freely available 1 1 http://www.physiome.org.nz/publications/nordsletten_blackett_ritman_bentley_smith_2005 . for further investigation into renal physiology and modeling studies.

scholarly journals In vivo three-dimensional photoacoustic imaging of the renal vasculature in preclinical rodent models

2018 ◽  
Vol 314 (6) ◽  
pp. F1145-F1153 ◽  
Author(s):  
Olumide Ogunlade ◽  
John J. Connell ◽  
Jennifer L. Huang ◽  
Edward Zhang ◽  
Mark F. Lythgoe ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Three Dimensional ◽  
Vascular Anatomy ◽  
Label Free ◽  
Renal Vasculature ◽  
Preclinical Imaging ◽  
Imaging Tool ◽  
And Function ◽  
Renal Vascular

Noninvasive imaging of the kidney vasculature in preclinical murine models is important for the assessment of renal development, studying diseases and evaluating new therapies but is challenging to achieve using existing imaging modalities. Photoacoustic imaging is a promising new technique that is particularly well suited to visualizing the vasculature and could provide an alternative to existing preclinical imaging methods for studying renal vascular anatomy and function. To investigate this, an all-optical Fabry-Perot-based photoacoustic scanner was used to image the abdominal region of mice. High-resolution three-dimensional, noninvasive, label-free photoacoustic images of the mouse kidney and renal vasculature were acquired in vivo. The scanner was also used to visualize and quantify differences in the vascular architecture of the kidney in vivo due to polycystic kidney disease. This study suggests that photoacoustic imaging could be utilized as a novel preclinical imaging tool for studying the biology of renal disease.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

convergent-beam diffraction from surfaces

1987 ◽  
Vol 45 ◽  
pp. 30-33
Author(s):  
J. A. Eades ◽  
A. E. Smith ◽  
D. F. Lynch
Keyword(s):  
Reciprocal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Three Dimensions ◽  
Plane Figure ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

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