scholarly journals Identification of vortex structures in a cohort of 204 intracranial aneurysms

2017 ◽  
Vol 14 (130) ◽  
pp. 20170021 ◽  
Author(s):  
Nicole Varble ◽  
Gabriel Trylesinski ◽  
Jianping Xiang ◽  
Kenneth Snyder ◽  
Hui Meng
Keyword(s):  
Three Dimensional ◽  
Morphological Characteristics ◽  
Aneurysm Rupture ◽  
Vortex Structures ◽  
Vortical Flow ◽  
Unruptured Aneurysms ◽  
Morphologic Characteristics ◽  
Definition Of ◽  
Dynamics Simulations ◽  
Inflow Jet

An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the Q -criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction ( vVF ) and the surface vortex fraction ( sVF ). Computational fluid dynamics simulations showed that the sVF , but not the vVF , discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.

Morphological and clinical risk factors for the rupture of anterior communicating artery aneurysms

2013 ◽  
Vol 118 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Hidetoshi Matsukawa ◽  
Akihiro Uemura ◽  
Motoharu Fujii ◽  
Minobu Kamo ◽  
Osamu Takahashi ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Multivariate Logistic Regression Analysis ◽  
Morphological Characteristics ◽  
Aneurysm Rupture ◽  
Anterior Communicating Artery ◽  
Parent Artery ◽  
Unruptured Aneurysms ◽  
Aneurysm Size ◽  
3D Ct Angiography ◽  
Anterior Direction

Object Patients with ruptured anterior communicating artery (ACoA) aneurysms have historically been observed to have poor neuropsychological outcomes, and ACoA aneurysms have accounted for a higher proportion of ruptured than unruptured aneurysms. Authors of this study aimed to investigate the morphological and clinical characteristics predisposing to ACoA aneurysm rupture. Methods Data from 140 consecutive patients with ACoA aneurysms managed at the authors' facility between July 2003 and November 2011 were retrospectively reviewed. Patients with (78) and without (62) aneurysm rupture were divided into groups, and morphological and clinical characteristics were compared. Morphological characteristics were evaluated based on 3D CT angiography and included aneurysm location, dominance of the A1 portion of the anterior cerebral artery, direction of the aneurysm dome around the ACoA, aneurysm bleb(s), size of the aneurysm and its neck, aneurysm–parent artery angle, and existence of other intracranial unruptured aneurysms. Results Patients with ruptured ACoA aneurysms were significantly younger (a higher proportion were younger than 60 years of age) than those with unruptured lesions, and a significantly smaller proportion had hypercholesterolemia. A significantly larger proportion of patients with ruptured aneurysms showed an anterior direction of the aneurysm dome around the ACoA, had a bleb(s), and/or had an aneurysm size ≥ 5 mm. Multivariate logistic regression analysis showed that an anterior direction of the aneurysm dome around the ACoA (OR 6.0, p = 0.0012), the presence of a bleb(s) (OR 22, p < 0.0001), and an aneurysm size ≥ 5 mm (OR 3.16, p = 0.035) were significantly associated with ACoA aneurysm rupture. Conclusions Findings in the present study demonstrated that the anterior projection of an ACoA aneurysm may be related to rupturing. The authors would perhaps recommend treatment to patients with unruptured ACoA aneurysms that have an anterior dome projection, a bleb(s), and a size ≥ 5 mm.

scholarly journals Angiographic Morphological Characteristics of Middle Cerebral Artery aneurysms

2018 ◽  
Vol 24 (3) ◽  
pp. 208-211
Author(s):  
Antônio Santos de Araújo Junior ◽  
Paulo Henrique Pires De Aguiar ◽  
Daniel De Carvalho Kirchhoff ◽  
Apio Cláudio Antunes ◽  
Marco Antonio Stefani ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Morphological Characteristics ◽  
Aneurysm Rupture ◽  
The Other ◽  
Single Institution ◽  
Unruptured Aneurysms ◽  
Middle Cerebral Artery Aneurysms ◽  
Vascular Neurosurgery ◽  
Time Of Admission

Background: The treatment of Middle Cerebral Artery Aneurysms (MCAA) and the relation of their morphology to the chance of  rupture are an important topic in vascular neurosurgery. Objective: To assess the correlation between MCAA morphology and 1) the chance of aneurysm rupture and 2) its morbimortality. Methods: Twenty-nine patients with MCAA at the M1 segment (4 patients had multiple aneurysms), were followed/ treated by our crew at a single institution over the last 5 years; 14 aneurysms were ruptured at the time of admission and 15 were diagnosed incidentally. Aneurysms were classified by shape and their geometries were correlated with rupture rate and their morbimortality. Results: Aneurysms measured between 7 and 10 mm in diameter (90% of the aneurysms), and there was no difference in size between the ruptured and unruptured aneurysms. Patients whose MCAAs were ruptured at admission were 3 times as likely than patients with unruptured aneurysms to have a transverse elliptic or inverted-pear-shaped aneurysm (21% vs 9%, p<0.05). On the other hand, patients with unruptured MCAAs were 6 times more likely than patients with ruptured MCAAs to have a pear-shaped aneurysm (36.3% vs 5.2%, p<0.001). Round-shaped aneurysms were more frequent overall, but they were not significantly more prone to rupture. Conclusion: Although this was a small group of patients, we conclude that transverse elliptic and inverted-pear-shaped aneurysms were more associated with rupture than round/ pear-shaped aneurysms.

Subarachnoid Hemorrhage

2016 ◽  
Author(s):  
Imoigele P Aisiku
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Delayed Cerebral Ischemia ◽  
Three Dimensional ◽  
Aneurysm Rupture ◽  
World Federation ◽  
Neurogenic Pulmonary Edema ◽  
Systemic Complications ◽  
Unruptured Aneurysms ◽  
Risk Of Rupture ◽  
Anterior Communicating Aneurysm

Subarachnoid hemorrhage (SAH) represents a small portion of cerebrovascular disease but a disproportionally large percentage of the morbidity and mortality. The overall prognosis depends on the volume of the initial bleeding, rebleeding, and the degree of delayed cerebral ischemia. The presence of cardiac manifestations and neurogenic pulmonary edema at the initial presentation indicates a higher degree of severity and systemic complications. This review covers the pathophysiology, stabilization and assessment, diagnosis and treatment, and disposition and outcomes of SAH. Figures show common saccular aneurysm locations, a noncontrast head computed tomographic scan of an SAH, an angiogram and surgical clipping of a broad-based anterior communicating aneurysm, and a three-dimensional reconstruction angiogram of a complex anterior communicating aneurysm with additional imaging of endoscopic stent-assisted coiling of the same aneurysm. Tables list the natural history of unruptured aneurysms and the annual risk of rupture, common clinical features and syndromes related to aneurysm location, the World Federation of Neurologic Surgeons grading system, the Hunt and Hess grading systems, and the Fisher scale. This review contains 4 highly rendered figures, 5 tables, and 144 references. Key words: aneurysm rupture, cerebral aneurysm, cerebral vasospasm, Fisher scale, Glasgow Coma Scale assessment, Hunt and Hess grading criteria, subarachnoid hemorrhage, World Federation of Neurologic Surgeons grading scale 

Quantified aneurysm shape and rupture risk

2005 ◽  
Vol 102 (2) ◽  
pp. 355-362 ◽  
Author(s):  
Madhavan L. Raghavan ◽  
Baoshun Ma ◽  
Robert E. Harbaugh
Keyword(s):  
Statistical Significance ◽  
Three Dimensional ◽  
Aneurysm Rupture ◽  
Content Type ◽  
Unruptured Aneurysms ◽  
Brain Vasculature ◽  
Shape Indices ◽  
Characteristic Area ◽  
Aneurysm Shape ◽  
Fine Print

Object. The authors investigated whether quantified shape or size indices could better discriminate between ruptured and unruptured aneurysms. Methods. Several custom algorithms were created to quantifiy the size and shape indices of intracranial aneurysms by using three-dimensional computerized tomography angiography models of the brain vasculature. Data from 27 patients with ruptured or unruptured aneurysms were evaluated in a blinded fashion to determine whether aneurysm size or shape better discriminated between the ruptured and unruptured groups. Five size and eight shape indices were calculated for each aneurysm. Two-tailed independent Student t-tests (significance p < 0.05) were used to determine statistically significant differences between ruptured and unruptured aneurysm groups for all 13 indices. Receiver-operating characteristic—area under curve analyses were performed for all indices to quantify the predictability of each index and to identify optimal threshold values. None of the five size indices were significantly different between the ruptured and unruptured aneurysms. Five of the eight shape indices were significantly different between the two lesion groups, and two other shape indices showed a trend toward discriminating between ruptured and unruptured aneurysms, although these differences did not reach statistical significance. Conclusions. Quantified shape is more effective than size in discriminating between ruptured and unruptured aneurysms. Further investigation will determine whether quantified aneurysm shape will prove to be a reliable predictor of aneurysm rupture.

scholarly journals TRT EVO: Advances in real-time thermodynamic tire modeling for vehicle dynamics simulations

2018 ◽  
Vol 233 (1) ◽  
pp. 121-135 ◽  
Author(s):  
Flavio Farroni ◽  
Michele Russo ◽  
Aleksandr Sakhnevych ◽  
Francesco Timpone
Keyword(s):  
Thermal Model ◽  
Thermal State ◽  
Three Dimensional ◽  
Research Activity ◽  
Frictional Performance ◽  
Tire Modeling ◽  
Definition Of ◽  
Dynamics Simulations ◽  
Pressure Stress ◽  
Heat Exchanges

Vehicle performances, especially in motorsport, are deeply affected by tire behavior and in particular by tire compound proper working conditions. In this research activity, a series of innovations have been introduced on the Thermo Racing Tire (a physical-analytical tire thermal model, based on Fourier’s law of heat transfer applied to a three-dimensional domain) in order to take into account all the main aspects actively involved in the thermal behavior of the tire, as the presence of exhausted gases eventually impacting at the rear axle and the inhomogeneous distribution of local variables (pressure, stress and sliding velocity) within the contact patch, caused in example by the tire camber angle. The new model developed considers the presence of the sidewalls, actively involved in the convective heat exchanges, respectively, with the external airflow and the inner gas fluid, located inside the inflation chamber. The aim of the new version of the tire thermal model is a better physical comprehension of all the phenomena concerning the contact with the asphalt and the prediction of the link between the thermal state and the frictional performance, crucial for the definition of an optimal wheel and vehicle setup.

Application of high-resolution field-emission LVSEM, backscatter imaging, immunogold staining to definition of the spatial distributions of two human neutrophil adherence receptors

1993 ◽  
Vol 51 ◽  
pp. 36-37
Author(s):  
Robert D. Nelson ◽  
Sharon R. Hasslen ◽  
Stanley L. Erlandsen
Keyword(s):  
Cell Surface ◽  
Surface Membrane ◽  
Three Dimensional ◽  
Human Neutrophils ◽  
Spatial Distributions ◽  
Immunogold Staining ◽  
Functional Control ◽  
Neutrophil Adherence ◽  
Definition Of ◽  
Mode Of Attachment

Receptors are commonly defined in terms of number per cell, affinity for ligand, chemical structure, mode of attachment to the cell surface, and mechanism of signal transduction. We propose to show that knowledge of spatial distribution of receptors on the cell surface can provide additional clues to their function and components of functional control.L-selectin and Mac-1 denote two receptor populations on the neutrophil surface that mediate neutrophil-endothelial cell adherence interactions and provide for targeting of neutrophil recruitment to sites of inflammation. We have studied the spatial distributions of these receptors using LVSEM and backscatter imaging of isolated human neutrophils stained with mouse anti-receptor (primary) antibody and goat anti-mouse (secondary) antibody conjugated to 12 nm colloidal gold. This combination of techniques provides for three-dimensional analysis of the expression of these receptors on different surface membrane domains of the neutrophil: the ruffles and microvilli that project from the cell surface, and the cell body between these projecting structures.

Instantaneous three-dimensional vorticity measurements in vortical flow over a delta wing

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1612-1620
Author(s):  
A. Honkan ◽  
J. Andreopoulos
Keyword(s):  
Delta Wing ◽  
Three Dimensional ◽  
Vortical Flow

scholarly journals Online biophysical predictions for SARS-CoV-2 proteins

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Luciano Kagami ◽  
Joel Roca-Martínez ◽  
Jose Gavaldá-García ◽  
Pathmanaban Ramasamy ◽  
K. Anton Feenstra ◽  
...  
Keyword(s):  
Protein Sequence ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Static Structure ◽  
Homologous Proteins ◽  
Structure Based Drug Design ◽  
Protein Protein Interaction ◽  
Link Type ◽  
Dynamics Simulations ◽  
Β Sheet

Abstract Background The SARS-CoV-2 virus, the causative agent of COVID-19, consists of an assembly of proteins that determine its infectious and immunological behavior, as well as its response to therapeutics. Major structural biology efforts on these proteins have already provided essential insights into the mode of action of the virus, as well as avenues for structure-based drug design. However, not all of the SARS-CoV-2 proteins, or regions thereof, have a well-defined three-dimensional structure, and as such might exhibit ambiguous, dynamic behaviour that is not evident from static structure representations, nor from molecular dynamics simulations using these structures. Main We present a website (https://bio2byte.be/sars2/) that provides protein sequence-based predictions of the backbone and side-chain dynamics and conformational propensities of these proteins, as well as derived early folding, disorder, β-sheet aggregation, protein-protein interaction and epitope propensities. These predictions attempt to capture the inherent biophysical propensities encoded in the sequence, rather than context-dependent behaviour such as the final folded state. In addition, we provide the biophysical variation that is observed in homologous proteins, which gives an indication of the limits of their functionally relevant biophysical behaviour. Conclusion The https://bio2byte.be/sars2/ website provides a range of protein sequence-based predictions for 27 SARS-CoV-2 proteins, enabling researchers to form hypotheses about their possible functional modes of action.

scholarly journals Proposing 3D Thermal Technology for Heritage Building Energy Monitoring

2021 ◽  
Vol 13 (8) ◽  
pp. 1537
Author(s):  
Antonio Adán ◽  
Víctor Pérez ◽  
José-Luis Vivancos ◽  
Carolina Aparicio-Fernández ◽  
Samuel A. Prieto
Keyword(s):  
Computer Vision ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Building Energy ◽  
Energy Monitoring ◽  
3D Computer Vision ◽  
Building Monitoring ◽  
Heritage Buildings ◽  
Heritage Building ◽  
Definition Of

The energy monitoring of heritage buildings has, to date, been governed by methodologies and standards that have been defined in terms of sensors that record scalar magnitudes and that are placed in specific positions in the scene, thus recording only some of the values sampled in that space. In this paper, however, we present an alternative to the aforementioned technologies in the form of new sensors based on 3D computer vision that are able to record dense thermal information in a three-dimensional space. These thermal computer vision-based technologies (3D-TCV) entail a revision and updating of the current building energy monitoring methodologies. This paper provides a detailed definition of the most significant aspects of this new extended methodology and presents a case study showing the potential of 3D-TCV techniques and how they may complement current techniques. The results obtained lead us to believe that 3D computer vision can provide the field of building monitoring with a decisive boost, particularly in the case of heritage buildings.

scholarly journals Polymer cyclization for the emergence of hierarchical nanostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chaojian Chen ◽  
Manjesh Kumar Singh ◽  
Katrin Wunderlich ◽  
Sean Harvey ◽  
Colette J. Whitfield ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Hierarchical Structures ◽  
Structural Similarity ◽  
Vital Role ◽  
Nanomaterial Synthesis ◽  
Wide Range ◽  
Linear Poly ◽  
Polymer Folding ◽  
Dynamics Simulations

AbstractThe creation of synthetic polymer nanoobjects with well-defined hierarchical structures is important for a wide range of applications such as nanomaterial synthesis, catalysis, and therapeutics. Inspired by the programmability and precise three-dimensional architectures of biomolecules, here we demonstrate the strategy of fabricating controlled hierarchical structures through self-assembly of folded synthetic polymers. Linear poly(2-hydroxyethyl methacrylate) of different lengths are folded into cyclic polymers and their self-assembly into hierarchical structures is elucidated by various experimental techniques and molecular dynamics simulations. Based on their structural similarity, macrocyclic brush polymers with amphiphilic block side chains are synthesized, which can self-assemble into wormlike and higher-ordered structures. Our work points out the vital role of polymer folding in macromolecular self-assembly and establishes a versatile approach for constructing biomimetic hierarchical assemblies.

Sign in / Sign up

Export Citation Format

Share Document