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dynamic parameters

David Hasler, Dominik Obrist
The flow field past a prosthetic aortic valve comprises many details that indicate whether the prosthesis is functioning well or not. It is, however, not yet fully understood how an optimal flow scenario would look, i.e. which subtleties of the fluid dynamics in place are essential regarding the durability and compatibility of a prosthetic valve. In this study, we measured and analyzed the 3D flow field in the vicinity of a bio-prosthetic heart valve in function of the aortic root size. The measurements were conducted within aortic root phantoms of different size, mounted in a custom-built hydraulic setup, which mimicked physiological flow conditions in the aorta...
2018: PloS One
Yuval B Simons, Kevin Bullaughey, Richard R Hudson, Guy Sella
Human genome-wide association studies (GWASs) are revealing the genetic architecture of anthropomorphic and biomedical traits, i.e., the frequencies and effect sizes of variants that contribute to heritable variation in a trait. To interpret these findings, we need to understand how genetic architecture is shaped by basic population genetics processes-notably, by mutation, natural selection, and genetic drift. Because many quantitative traits are subject to stabilizing selection and because genetic variation that affects one trait often affects many others, we model the genetic architecture of a focal trait that arises under stabilizing selection in a multidimensional trait space...
March 16, 2018: PLoS Biology
Ayaka Sato, Yuya Ikeda, Koichi Yamaguchi, Varun Vohra
Facile detection and the identification of hazardous organic solvents are essential for ensuring global safety and avoiding harm to the environment caused by industrial wastes. Here, we present a simple method for the fabrication of silver-coated monodisperse polystyrene nanoparticle photonic structures that are embedded into a polydimethylsiloxane (PDMS) matrix. These hybrid materials exhibit a strong green iridescence with a reflectance peak at 550 nm that originates from the close-packed arrangement of the nanoparticles...
March 16, 2018: Nanomaterials
Alisa L Gallant, Walt Sadinski, Jesslyn F Brown, Gabriel B Senay, Mark F Roth
Assessing climate-related ecological changes across spatiotemporal scales meaningful to resource managers is challenging because no one method reliably produces essential data at both fine and broad scales. We recently confronted such challenges while integrating data from ground- and satellite-based sensors for an assessment of four wetland-rich study areas in the U.S. Midwest. We examined relations between temperature and precipitation and a set of variables measured on the ground at individual wetlands and another set measured via satellite sensors within surrounding 4 km² landscape blocks...
March 16, 2018: Sensors
Alessandro Micarelli, Andrea Viziano, David Della-Morte, Ivan Augimeri, Marco Alessandrini
OBJECTIVE: Considering the altered multisensory signal compensation during senescence, the aim of the present study was to evaluate the integration rearrangements in unilateral vestibular hypofunction (UVH) during age-related cognitive decline. STUDY DESIGN: Cross-sectional study. SETTING: Longitudinal cohort study unit and of University tertiary referral center. PATIENTS: Older UVH individuals ≥ 55 years with Mild Cognitive Impairment (MCI) or Alzheimer Disease (AD) and matched UVH control group with age-appropriate cognitive function...
March 15, 2018: Otology & Neurotology
Diyuan Zong, Zhen Yang, Yuanyuan Duan
The wetting kinetics of droplets on lyophilic pillar-arrayed substrates is the driving mechanism of several natural phenomena (e.g., insect capturing by Nepenthes) and many industrial technologies (e.g., gas-liquid separation). For a lyophilic pillar-arrayed surface, a fringe film is formed ahead of the contact line, resulting in distinct wetting kinetics, which needs further investigation. In this study, Si(100) substrates with square micropillars were used to investigate the early spreading of droplets on lyophilic pillar-arrayed surfaces through the droplet-spreading method...
March 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Diego Jaramillo-Cano, Maud Formanek, Christos N Likos, Manuel Camargo
Star block-copolymers (SBCs) have been demonstrated to constitute self-assembling building blocks with specific softness, functionalization, shape and flexibility. In this work we study the behaviour of an isolated SBC under shear flow by means of particle-based multi-scale simulations. We systematically analyse the conformational properties of low-functionality stars as well as the formation of attractive patches on their corona as a function of the shear rate. We cover a wide range of system parameters, including functionality, amphiphilicity and solvent quality...
March 16, 2018: Journal of Physical Chemistry. B
Hamish Low, Luigi Pistaferri
We provide a life-cycle framework for comparing insurance and disincentive effects of disability benefits. The risks that individuals face and the parameters of the Disability Insurance (DI ) program are estimated from consumption, health, disability insurance, and wage data. We characterize the effects of disability insurance and study how policy reforms impact behavior and welfare. DI features high rejection rates of disabled applicants and some acceptance of healthy applicants. Despite worse incentives, welfare increases as programs become less strict or generosity increases...
October 2018: American Economic Review
Kara Pham, Emma Turian, Kai Liu, Shuwang Li, John Lowengrub
We consider the nonlinear dynamics of an avascular tumor at the tissue scale using a two-fluid flow Stokes model, where the viscosity of the tumor and host microenvironment may be different. The viscosities reflect the combined properties of cell and extracellular matrix mixtures. We perform a linear morphological stability analysis of the tumors, and we investigate the role of nonlinearity using boundary-integral simulations in two dimensions. The tumor is non-necrotic, although cell death may occur through apoptosis...
March 15, 2018: Journal of Mathematical Biology
Philipp Marx, Wojciech Kowalczyk, Aydin Demircioglu, Gary Neil Brault, Hermann Wendt, Sharaf-Eldin Shehada, Konstantinos Tsagakis, Mohamed El Gabry, Heinz Jakob, Daniel Wendt
The aim of the present in vitro study was the evaluation of the fluid dynamical performance of the Carpentier-Edwards PERIMOUNT Magna Ease depending on the prosthetic size (21, 23, and 25 mm) and the cardiac output (3.6-6.4 L/min). A self-constructed flow channel in combination with particle image velocimetry (PIV) enabled precise results with high reproducibility, focus on maximal and local peek velocities, strain, and velocity gradients. These flow parameters allow insights into the generation of forces that act on blood cells and the aortic wall...
2018: BioMed Research International
Feng Feng, Fulin Qiang, Aijun Shen, Donghui Shi, Aiyan Fu, Haiming Li, Mingzhu Zhang, Ganlin Xia, Peng Cao
Objective: To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) with that of18 F-fluorodeoxyglucose (18 F-FDG) positron emission tomography/computed tomography (PET/CT) in the differentiation of malignant and benign solitary pulmonary nodules (SPNs). Methods: Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs...
February 2018: Chinese Journal of Cancer Research, Chung-kuo Yen Cheng Yen Chiu
Nobuhisa Ishii, Kazuhide Tomita, Shinsuke Suetake, Yukako Okuno, Kenta Kawamura, Reiko Takeshima, Hirotaka Ohse, Shigeyuki Imura
[Purpose] It is unclear whether diaphragmatic breathing (DB) results in lower respiratory muscle oxygen consumption during dynamic exercise. The purpose of this study was to compare oxygen consumption in the respiratory muscles (VO2 rm) with thoracic breathing (TB) and with DB, in healthy males during hyperventilation. [Subjects and Methods] Ten healthy men participated in this study. The subjects sat on a chair with the backrest reclined at an angle of 60 degrees. Respiratory parameters were measured breath by breath, using an expired gas analyzer...
February 2018: Journal of Physical Therapy Science
John J Elias, Kerwyn C Jones, S Cyrus Rezvanifar, Joseph N Gabra, Melanie A Morscher, Andrew J Cosgarea
BACKGROUND: Continued patellar instability can occur following medial patellofemoral ligament (MPFL) reconstruction. Computational simulation of function was used to investigate the influence of the lateral position of the tibial tuberosity, trochlear dysplasia and patella alta on lateral patellar tracking following MPFL reconstruction. METHODS: Multibody dynamic simulation models were developed to represent nine knees being treated for recurrent patellar instability...
March 12, 2018: Knee
Joseph Páez Chávez, Dirk Jungmann, Stefan Siegmund
The paper presents a comprehensive numerical study of mathematical models used to describe complex biological systems in the framework of integrated pest management. Our study considers two specific ecosystems that describe the application of control mechanisms based on pesticides and natural enemies, implemented in an impulsive and periodic manner, due to which the considered models belong to the class of impulsive differential equations. The present work proposes a numerical approach to study such type of models in detail, via the application of path-following (continuation) techniques for nonsmooth dynamical systems, via the novel continuation platform COCO (Dankowicz and Schilder)...
December 2018: Journal of Biological Dynamics
Itay Azizi, Yitzhak Rabin
We use Langevin dynamics simulations to study the growth kinetics and the steady-state properties of condensed clusters in a dilute two-dimensional system of particles that are all different (APD) in the sense that each particle is characterized by a randomly chosen interaction parameter. The growth exponents, the transition temperatures, and the steady-state properties of the clusters and of the surrounding gas phase are obtained and compared with those of one-component systems. We investigate the fractionation phenomenon, i...
March 14, 2018: Journal of Chemical Physics
Shuai Zhang, Burkhard Militzer, Lorin X Benedict, François Soubiran, Philip A Sterne, Kevin P Driver
Carbon-hydrogen plasmas and hydrocarbon materials are of broad interest to laser shock experimentalists, high energy density physicists, and astrophysicists. Accurate equations of state (EOSs) of hydrocarbons are valuable for various studies from inertial confinement fusion to planetary science. By combining path integral Monte Carlo (PIMC) results at high temperatures and density functional theory molecular dynamics results at lower temperatures, we compute the EOSs for hydrocarbons from simulations performed at 1473 separate (ρ, T)-points distributed over a range of compositions...
March 14, 2018: Journal of Chemical Physics
E Pafong Sanjon, B Drossel, M Vogel
Silica is a network-forming liquid that shares many properties with water due to its tetrahedral structure. It undergoes a transition from a fragile to a strong liquid as the temperature is decreased, which is accompanied by a structural change to lower density and higher tetrahedral order. In order to disentangle the effects of Coulomb and van der Waals interactions on the structure and dynamics of liquid silica, we modify the bond polarity by changing the partial charges assigned to each atom. Using molecular dynamics simulations, we show that density, tetrahedral order, and structural relaxation times decrease when reducing bond polarity...
March 14, 2018: Journal of Chemical Physics
Oyetunde Kazeem Ekeolu, Olamide Elizabeth Adebiyi
BACKGROUND: Hematological parameters are vital diagnostic tools for understanding health dynamics of humans and animals. Franquet's fruit bat (Epomops franqueti) is host to several parasites such as protozoa, bacteria, viruses and mites. Yet, studies exploring the values of its blood components with interest for research or food purposes are scarce. Thus, this study was carried out to investigate the hematological values of the adult E. franqueti. METHODS: Seventeen (nine female and eight male) apparently healthy adult E...
March 15, 2018: Journal of Basic and Clinical Physiology and Pharmacology
Yong Yang, Brent A Langellier, Ivana Stankov, Jonathan Purtle, Katherine L Nelson, Ana V Diez Roux
OBJECTIVES: Daily transport may impact depression risk among older adults through several pathways including facilitating the ability to meet basic needs, enabling and promoting contact with other people and nature, and promoting physical activity (e.g. through active transportation such as walking or walking to public transit). Both daily transport and depression are influenced by the neighborhood environment. To provide insights into how transport interventions may affect depression in older adults, we developed a pilot agent-based model to explore the contribution of daily transport and neighborhood environment to older adults' depression in urban areas...
March 15, 2018: Aging & Mental Health
A Zh Fursova, N V Chubar, M S Tarasov, M A Vasilyeva, G G Pustovaya, I F Saifullina
The apparent success of antiangiogenic therapy in patients with neovascular age-related macular degeneration (nAMD) shows the significance of effect prognosis and continuous observation. PURPOSE: to study the influence of prognostic factors on the dynamics of functional and morphological response during anti-VEGF therapy in patients with nAMD. MATERIAL AND METHODS: Retrospective analysis of anti-angiogenic therapy results was performed on the data of 1020 patients with nAMD...
2018: Vestnik Oftalmologii
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