keyword
MENU ▼
Read by QxMD icon Read
search

surface curvature

keyword
https://www.readbyqxmd.com/read/28538996/the-relationship-between-surface-curvature-and-abdominal-aortic-aneurysm-wall-stress
#1
Sergio Ruiz de Galarreta, Aitor Cazon, Raúl Antón, Ender A Finol
The maximum diameter criterion is the most important factor when predicting risk of rupture of abdominal aortic aneurysms (AAA). An elevated wall stress has also been linked to a high risk of aneurysm rupture, yet is an uncommon clinical practice to compute AAA wall stress. The purpose of this study is to assess whether other characteristics of the AAA geometry are statistically correlated with wall stress. Using in-house segmentation and meshing algorithms, thirty patient-specific AAA models were generated for finite element analysis...
May 24, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28538668/biomechanical-modeling-of-pterygium-radiation-surgery-a-retrospective-case-study
#2
Bojan Pajic, Daniel M Aebersold, Andreas Eggspuehler, Frederik R Theler, Harald P Studer
Pterygium is a vascularized, invasive transformation on the anterior corneal surface that can be treated by Strontium-/Yttrium90 beta irradiation. Finite element modeling was used to analyze the biomechanical effects governing the treatment, and to help understand clinically observed changes in corneal astigmatism. Results suggested that irradiation-induced pulling forces on the anterior corneal surface can cause astigmatism, as well as central corneal flattening. Finite element modeling of corneal biomechanics closely predicted the postoperative corneal surface (astigmatism error -0...
May 24, 2017: Sensors
https://www.readbyqxmd.com/read/28535145/substrate-curvature-regulates-cell-migration
#3
Xiuxiu He, Yi Jiang
Cell migration is essential in many aspects of biology. Many basic migration processes, including adhesion, membrane protrusion and tension, cytoskeletal polymerization, and contraction, have to act in concert to regulate cell migration. At the same time, substrate topography modulates these processes. In this work, we study how substrate curvature at micrometer scale regulates cell motility. We have developed a 3D mechanical model of single cell migration and simulated migration on curved substrates with different curvatures...
May 23, 2017: Physical Biology
https://www.readbyqxmd.com/read/28532212/soft-matter-in-lipid-protein-interactions
#4
Michael F Brown
Membrane lipids and cellular water (soft matter) are becoming increasingly recognized as key determinants of protein structure and function. Their influences can be ascribed to modulation of the bilayer properties or to specific binding and allosteric regulation of protein activity. In this review, we first consider hydrophobic matching of the intramembranous proteolipid boundary to explain the conformational changes and oligomeric states of proteins within the bilayer. Alternatively, membranes can be viewed as complex fluids, whose properties are linked to key biological functions...
May 22, 2017: Annual Review of Biophysics
https://www.readbyqxmd.com/read/28530795/modelling-living-cells-response-to-surface-tension-and-chemical-patterns
#5
Marco Macis, Francesca Lugli, Francesco Zerbetto
Mechanobiology is an important epigenetic factor. It influences cell functioning and bears on gene induction, protein synthesis, cell growth and differentiation. In the presence of patterned chemical cues, living cells can take shapes that are far from that of a drop of fluid. These shapes are characterized by inward curvatures that are pinned at the points of location of the cues. The mechano-chemical interactions that orchestrate cell behavior is simulated and controlled by modeling the cells as made by parcels of fluid...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28527981/an-identification-of-the-soft-polyelectrolyte-gel-like-layer-on-silica-colloids-using-atomic-force-and-electron-microscopy
#6
Jiří Škvarla, Juraj Škvarla
A procedure is introduced for measuring the radius of spherical colloid particles from the curvature of upper parts of their central cross-sectional profiles obtained by atomic force microscopy (AFM). To minimize the possible compression and displacement of the spheres, AFM is operated in a mode rendering a constant ultralow pN force on the tip. The procedure allows us to evaluate the mean radius of nearly monodisperse submicrometer spheres of silica in their natively hydrated state in aqueous electrolyte solutions, irrespective of whether they are coagulated or not...
May 16, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28527852/cyclic-and-torsional-fatigue-resistance-of-reciprocating-single-files-manufactured-by-different-nickel-titanium-alloys
#7
Murilo P Alcalde, Mario Tanomaru-Filho, Clovis M Bramante, Marco Antonio H Duarte, Juliane Maria Guerreiro-Tanomaru, Jader Camilo-Pinto, Marcus Vinicius Reis Só, Rodrigo Ricci Vivan
INTRODUCTION: The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the following reciprocating single-file systems: ProDesign R 25.06 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), Reciproc R25 (VDW GmbH, Munich, Germany), and Unicone L25 (Medin SA, Nové Město in Moravě, Czech Republic). METHODS: Sixty instruments of the ProDesign R, Reciproc R25, and Unicone L25 systems (n = 20) were used. Cyclic fatigue resistance was tested measuring the time to failure in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature (n = 10)...
May 17, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28527187/quantitative-stereological-analysis-of-the-highly-porous-hydroxyapatite-scaffolds-using-x-ray-cm-and-sem
#8
Justyna Zygmuntowicz, Aneta Zima, Joanna Czechowska, Karol Szlazak, Anna Ślosarczyk, Katarzyna Konopka
BACKGROUND: Material properties of the scaffolds as well as their microstructure are vital in determining in vivo cellular response. Three-dimensional (3D), highly porous scaffolds are used in tissue engineering to provide a suitable microenvironment and to support regeneration of bone. Both pore sizes and their architecture, in particular interconnection density, impact functionality of scaffold during its biomedical applications. OBJECTIVE: In this paper a comparative study of the microstructure of highly porous hydroxyapatite scaffolds produced via gelcasting of foamed slurries and replication of polyurethane sponge were carried out...
2017: Bio-medical Materials and Engineering
https://www.readbyqxmd.com/read/28525314/malaria-parasite-limp-protein-regulates-sporozoite-gliding-motility-and-infectivity-in-mosquito-and-mammalian-hosts
#9
Jorge M Santos, Saskia Egarter, Vanessa Zuzarte-Luís, Hirdesh Kumar, Catherine A Moreau, Jessica Kehrer, Andreia Pinto, Mário da Costa, Blandine Franke-Fayard, Chris J Janse, Friedrich Frischknecht, Gunnar R Mair
Gliding motility allows malaria parasites to migrate and invade tissues and cells in different hosts. It requires parasite surface proteins to provide attachment to host cells and extracellular matrices. Here, we identify the Plasmodium protein LIMP (the name refers to a gliding phenotype in the sporozoite arising from epitope tagging of the endogenous protein) as a key regulator for adhesion during gliding motility in the rodent malaria model P. berghei. Transcribed in gametocytes, LIMP is translated in the ookinete from maternal mRNA, and later in the sporozoite...
May 2, 2017: ELife
https://www.readbyqxmd.com/read/28515620/stationary-acceleration-of-frenet-curves
#10
Nemat Abazari, Martin Bohner, Ilgin Sağer, Yusuf Yayli
In this paper, the stationary acceleration of the spherical general helix in a 3-dimensional Lie group is studied by using a bi-invariant metric. The relationship between the Frenet elements of the stationary acceleration curve in 4-dimensional Euclidean space and the intrinsic Frenet elements of the Lie group is outlined. As a consequence, the corresponding curvature and torsion of these curves are computed. In Minkowski space, for the curves on a timelike surface to have a stationary acceleration, a necessary and sufficient condition is refined...
2017: Journal of Inequalities and Applications
https://www.readbyqxmd.com/read/28514491/3d-image-based-morphometric-analysis-of-the-scapular-neck-length-in-subjects-undergoing-reverse-shoulder-arthroplasty
#11
P Simon, M Diaz, M Cusick, B Santoni, M Frankle
INTRODUCTION: Scapular notching after RSA may, in part, be related to a patient's scapular morphology. The purpose of this study was to develop a novel 3D measurement technique to describe infraglenoid tubercle morphometry. We hypothesize that the parameters describing infraglenoid tubercle would be normally distributed and would correlate with individual's demographics and glenoid morphometry. MATERIALS AND METHODS: A group of 110 subjects treated with RSA were evaluated...
May 17, 2017: Clinical Anatomy
https://www.readbyqxmd.com/read/28514248/foveal-curvature-and-asymmetry-assessed-using-optical-coherence-tomography
#12
Dean A VanNasdale, Amanda Eilerman, Aaron Zimmerman, Nicky Lai, Keith Ramsey, Loraine T Sinnott
PURPOSE: The aims of this study were to use cross-sectional optical coherence tomography imaging and custom curve fitting software to evaluate and model the foveal curvature as a spherical surface and to compare the radius of curvature in the horizontal and vertical meridians and test the sensitivity of this technique to anticipated meridional differences. METHODS: Six 30-degree foveal-centered radial optical coherence tomography cross-section scans were acquired in the right eye of 20 clinically normal subjects...
June 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
https://www.readbyqxmd.com/read/28505495/generalized-boussinesq-scriven-surface-fluid-model-with-curvature-dissipation-for-liquid-surfaces-and-membranes
#13
Oscar F Aguilar Gutierrez, Edtson E Herrera Valencia, Alejandro D Rey
Curvature dissipation is relevant in synthetic and biological processes, from fluctuations in semi-flexible polymer solutions, to buckling of liquid columns, tomembrane cell wall functioning. We present a micromechanical model of curvature dissipation relevant to fluid membranes and liquid surfaces based on a parallel surface parameterization and a stress constitutive equation appropriate for anisotropic fluids and fluid membranes.The derived model, aimed at high curvature and high rate of change of curvature in liquid surfaces and membranes, introduces additional viscous modes not included in the widely used 2D Boussinesq-Scriven rheological constitutive equation for surface fluids...
May 8, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28504469/subtle-but-ubiquitous-selection-on-body-size-in-a-natural-population-of-collared-flycatchers-over-33-years
#14
Mats Björklund, Lars Gustafsson
Understanding the magnitude and long-term patterns of selection in natural populations is of importance, for example, when analyzing the evolutionary impact of climate change. We estimated univariate and multivariate directional, quadratic and correlational selection on four morphological traits (adult wing, tarsus and tail length, body mass) over a time period of 33 years (≈ 19 000 observations) in a nest-box breeding population of collared flycatchers (Ficedula albicollis). In general, selection was weak in both males and females over the years regardless of fitness measure (fledged young, recruits and survival) with only few cases with statistically significant selection...
May 15, 2017: Journal of Evolutionary Biology
https://www.readbyqxmd.com/read/28504295/increased-permeability-of-oxygen-atoms-through-graphene-with-ripples
#15
Guangyu He, Tao Liang, Qi Wang, Mingsheng Xu, Yingchun Liu
Graphene is an ideal membrane for selective separation because of its unique properties and single-layer structure. Considerable efforts have been made to alter the permeability of graphene. In this study, we investigate the pathways for an oxygen atom to pass through graphene sheets. We also identify the effect of the ripple's curvature in graphene sheets on the energy barrier of permeation through density functional theory calculations. Results show that oxygen atoms can easily pass through the concave side of graphene ripples with a large curvature...
May 15, 2017: Soft Matter
https://www.readbyqxmd.com/read/28496302/goldmann-tonometer-error-correcting-prism-clinical-evaluation
#16
Sean McCafferty, Garrett Lim, William Duncan, Eniko T Enikov, Jim Schwiegerling, Jason Levine, Corin Kew
PURPOSE: Clinically evaluate a modified applanating surface Goldmann tonometer prism designed to substantially negate errors due to patient variability in biomechanics. METHODS: A modified Goldmann prism with a correcting applanation tonometry surface (CATS) was mathematically optimized to minimize the intraocular pressure (IOP) measurement error due to patient variability in corneal thickness, stiffness, curvature, and tear film adhesion force. A comparative clinical study of 109 eyes measured IOP with CATS and Goldmann prisms...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28494282/anthropogenic-fibres-in-the-baltic-sea-water-column-field-data-laboratory-and-numerical-testing-of-their-motion
#17
A Bagaev, A Mizyuk, L Khatmullina, I Isachenko, I Chubarenko
Distribution of microplastics particles (MPs) in the water column is investigated on the base of 95 water samples collected from various depths in the Baltic Sea Proper in 2015-2016. Fibres are the prevalent type of MPs: 7% of the samples contained small films; about 40% had (presumably) paint flakes, while 63% contained coloured fibres in concentrations from 0.07 to 2.6 items per litre. Near-surface and near-bottom layers (defined as one tenth of the local depth) have 3-5 times larger fibre concentrations than intermediate layers...
May 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28490804/epitaxial-growth-of-cu-001-thin-films-onto-si-001-using-a-single-step-hipims-process
#18
Felipe Cemin, Daniel Lundin, Clarisse Furgeaud, Anny Michel, Guillaume Amiard, Tiberiu Minea, Gregory Abadias
We report on a new route to grow epitaxial copper (Cu) ultra-thin films (up to 150 nm thick) at ambient temperature on Si(001) wafers covered with native oxide without any prior chemical etching or plasma cleaning of the substrate. It consists of a single-step deposition process using high power impulse magnetron sputtering (HiPIMS) and substrate biasing. For a direct current (DC) substrate bias voltage of -130 V, Cu/Si heteroepitaxial growth is achieved by HiPIMS following the Cu(001) [100]//Si(001) [110] orientation, while under the same average deposition conditions, but using conventional DC magnetron sputtering, polycrystalline Cu films with [111] preferred orientation are deposited...
May 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28490775/metasurface-freeform-nanophotonics
#19
Alan Zhan, Shane Colburn, Christopher M Dodson, Arka Majumdar
Freeform optics aims to expand the toolkit of optical elements by allowing for more complex phase geometries beyond rotational symmetry. Complex, asymmetric curvatures are employed to enhance the performance of optical components while minimizing their size. Unfortunately, these high curvatures and complex forms are often difficult to manufacture with current technologies, especially at the micron scale. Metasurfaces are planar sub-wavelength structures that can control the phase, amplitude, and polarization of incident light, and can thereby mimic complex geometric curvatures on a flat, wavelength-scale thick surface...
May 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28487638/construction-of-individual-morphological-brain-networks-with-multiple-morphometric-features
#20
Wan Li, Chunlan Yang, Feng Shi, Shuicai Wu, Qun Wang, Yingnan Nie, Xin Zhang
In recent years, researchers have increased attentions to the morphological brain network, which is generally constructed by measuring the mathematical correlation across regions using a certain morphometric feature, such as regional cortical thickness and voxel intensity. However, cerebral structure can be characterized by various factors, such as regional volume, surface area, and curvature. Moreover, most of the morphological brain networks are population-based, which has limitations in the investigations of individual difference and clinical applications...
2017: Frontiers in Neuroanatomy
keyword
keyword
40459
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"