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https://www.readbyqxmd.com/read/29792988/towards-quantitative-prediction-of-the-performance-of-dry-powder-inhalers-by-multi-scale-simulations-and-experiments
#1
Duy Nguyen, Johan Remmelgas, Ingela Niklasson Björn, Berend van Wachem, Kyrre Thalberg
This work demonstrates the use of multi-scale simulations coupled with experiments to build a quantitative prediction tool for the performance of adhesive mixtures in a dry powder inhaler (DPI). Using discrete element model (DEM), the behaviour of fine-carrier particle assemblies upon different mechanisms encountered during dose entrainment and dispersion can be described at the individual particle level. Combining these results with computational fluid dynamics (CFD) simulations, the complete dosing event from a DPI can be captured and key performance measures can be extracted...
May 21, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29787939/digbody-%C3%A2-a-new-3d-modeling-tool-for-nasal-virtual-surgery
#2
M A Burgos, E Sanmiguel-Rojas, Narinder Singh, F Esteban-Ortega
BACKGROUND AND PURPOSE: Recent studies have demonstrated that a significant number of surgical procedures for nasal airway obstruction (NAO) have a high rate of surgical failure. In part, this problem is due to the lack of reliable objective clinical parameters to aid surgeons during preoperative planning. Modeling tools that allow virtual surgery to be performed do exist, but all require direct manipulation of computed tomography (CT) or magnetic resonance imaging (MRI) data. Specialists in Rhinology have criticized these tools for their complex user interface, and have requested more intuitive, user-friendly and powerful software to make virtual surgery more accessible and realistic...
May 16, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29787689/patient-specific-multiscale-computational-fluid-dynamics-assessment-of-embolization-rates-in-the-hybrid-norwood-effects-of-size-and-placement-of-the-reverse-blalock-taussig-shunt
#3
Ray Otto Prather, John Seligson, Marcus Ni, Eduardo Divo, Alain Kassab, William DeCampli
The hybrid Norwood operation is performed to treat hypoplastic left heart syndrome. Distal arch obstruction may compromise flow to the brain. In a variant of this procedure, a synthetic graft (RBTS) is placed between the pulmonary trunk and innominate artery to improve upper torso blood flow. Thrombi originating in the graft may embolize to the brain. In this study we used computational fluid dynamics (CFD) and particle tracking to investigate the patterns of particle embolization as a function of the anatomic position of the RBTS...
May 22, 2018: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/29786774/computational-fluid-dynamics-modeling-of-the-human-pulmonary-arteries-with-experimental-validation
#4
Alifer D Bordones, Matthew Leroux, Vitaly O Kheyfets, Yu-An Wu, Chia-Yuan Chen, Ender A Finol
Pulmonary hypertension (PH) is a chronic progressive disease characterized by elevated pulmonary arterial pressure, caused by an increase in pulmonary arterial impedance. Computational fluid dynamics (CFD) can be used to identify metrics representative of the stage of PH disease. However, experimental validation of CFD models is often not pursued due to the geometric complexity of the model or uncertainties in the reproduction of the required flow conditions. The goal of this work is to validate experimentally a CFD model of a pulmonary artery phantom using a particle image velocimetry (PIV) technique...
May 21, 2018: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/29783109/anti-inflammatory-potential-of-alginic-acid-from-sargassum-horneri-against-urban-aerosol-induced-inflammatory-responses-in-keratinocytes-and-macrophages
#5
I P Shanura Fernando, Thilina U Jayawardena, K K Asanka Sanjeewa, Lei Wang, You-Jin Jeon, Won Woo Lee
The airborne particulate pollutants originating in the deserts of Mongolia and China which becomes contaminated with industrial effluents and traffic emissions while moving with the wind currents towards East Asia has recently become a serious environmental and health issue in the region. They cause asthma, collateral lung tissue damage, oxidative stress, allergic reactions, and inflammation. The current study was undertaken to evaluate the protective effects of alginate extracted from the invasive alga Sargassum horneri (SHA) against fine dust collected from Beijing, China (Chinese fine dust; CFD)...
May 18, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29782927/modeling-the-odor-landscape-resulting-from-the-pumping-behavior-of-bivalve-clams-in-the-presence-of-predators
#6
A Alvarez
Motivated by experimental findings, a computational fluid dynamics (CFD) model was used to investigate whether the clam Mercenaria mercenaria may alter its cue downstream variability by an exhalant random pumping behavior. This behavior was hypothesized to occur in the presence of predator chemical signals in order to prevent successful tracking by the predator. Simulated downstream flow and mixing conditions derived from the random nature of the clam exhalant jet in a crossflow were analyzed by computing an intermittency factor, determining the field of finite-time Lyapunov exponents (FTLEs) and identifying the resulting Lagrangian coherent structures (LCSs)...
May 18, 2018: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29780181/dust-control-by-air-blocking-shelves-and-dust-collector-to-bailing-airflow-ratios-for-a-surface-mine-drill-shroud
#7
Y Zheng, W R Reed, J D Potts, M Li, J P Rider
The National Institute for Occupational Safety and Health (NIOSH) recently developed a series of validated models utilizing computational fluid dynamics (CFD) to study the effects of air-blocking shelves on airflows and respirable dust distribution associated with medium-sized surface blasthole drill shrouds as part of a dry dust collector system. Using validated CFD models, three different air-blocking shelves were included in the present study: a 15.2-cm (6-in.)-wide shelf; a 7.6-cm (3-in.)-wide shelf; and a 7...
May 2018: Mining Engineering
https://www.readbyqxmd.com/read/29775665/use-of-computational-fluid-dynamics-for-improving-freeze-dryers-design-and-process-understanding-part-1-modelling-the-lyophilisation-chamber
#8
Antonello A Barresi, Valeria Rasetto, Daniele L Marchisio
This manuscript shows how computational models, mainly based on Computational Fluid Dynamics (CFD), can be used to simulate different parts of an industrial freeze-drying equipment and to properly design them; in particular, the freeze-dryer chamber and the duct connecting the chamber with the condenser, with the valves and vanes eventually present are analysed in this work. In Part 1, it will be shown how CFD can be employed to improve specific designs, to perform geometry optimization, to evaluate different design choices and how it is useful to evaluate the effect on product drying and batch variance...
May 15, 2018: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/29769595/turbulence-and-cavitation-suppression-by-quaternary-ammonium-salt-additives
#9
Homa Naseri, Kieran Trickett, Nicholas Mitroglou, Ioannis Karathanassis, Phoevos Koukouvinis, Manolis Gavaises, Robert Barbour, Dale Diamond, Sarah E Rogers, Maurizio Santini, Jin Wang
We identify the physical mechanism through which newly developed quaternary ammonium salt (QAS) deposit control additives (DCAs) affect the rheological properties of cavitating turbulent flows, resulting in an increase in the volumetric efficiency of clean injectors fuelled with diesel or biodiesel fuels. Quaternary ammonium surfactants with appropriate counterions can be very effective in reducing the turbulent drag in aqueous solutions, however, less is known about the effect of such surfactants in oil-based solvents or in cavitating flow conditions...
May 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29760665/left-ventricular-trabeculations-decrease-the-wall-shear-stress-and-increase-the-intra-ventricular-pressure-drop-in-cfd-simulations
#10
Federica Sacco, Bruno Paun, Oriol Lehmkuhl, Tinen L Iles, Paul A Iaizzo, Guillaume Houzeaux, Mariano Vázquez, Constantine Butakoff, Jazmin Aguado-Sierra
The aim of the present study is to characterize the hemodynamics of left ventricular (LV) geometries to examine the impact of trabeculae and papillary muscles (PMs) on blood flow using high performance computing (HPC). Five pairs of detailed and smoothed LV endocardium models were reconstructed from high-resolution magnetic resonance images (MRI) of ex-vivo human hearts. The detailed model of one LV pair is characterized only by the PMs and few big trabeculae, to represent state of art level of endocardial detail...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29759947/a-simplified-method-to-account-for-wall-motion-in-patient-specific-blood-flow-simulations-of-aortic-dissection-comparison-with-fluid-structure-interaction
#11
Mirko Bonfanti, Stavroula Balabani, Mona Alimohammadi, Obiekezie Agu, Shervanthi Homer-Vanniasinkam, Vanessa Díaz-Zuccarini
Aortic dissection (AD) is a complex and highly patient-specific vascular condition difficult to treat. Computational fluid dynamics (CFD) can aid the medical management of this pathology, yet its modelling and simulation are challenging. One aspect usually disregarded when modelling AD is the motion of the vessel wall, which has been shown to significantly impact simulation results. Fluid-structure interaction (FSI) methods are difficult to implement and are subject to assumptions regarding the mechanical properties of the vessel wall, which cannot be retrieved non-invasively...
May 11, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/29758884/the-impact-of-urban-open-space-and-lift-up-building-design-on-building-intake-fraction-and-daily-pollutant-exposure-in-idealized-urban-models
#12
Chenyuan Sha, Xuemei Wang, Yuanyuan Lin, Yifan Fan, Xi Chen, Jian Hang
Sustainable urban design is an effective way to improve urban ventilation and reduce vehicular pollutant exposure to urban residents. This paper investigated the impacts of urban open space and 'lift-up' building design on vehicular CO (carbon monoxide) exposure in typical three-dimensional (3D) urban canopy layer (UCL) models under neutral atmospheric conditions. The building intake fraction (IF) represents the fraction of total vehicular pollutant emissions inhaled by residents when they stay at home. The building daily CO exposure (Et ) means the extent of human beings' contact with CO within one day indoor at home...
August 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29756207/quantification-of-tissue-engineered-trachea-performance-with-computational-fluid-dynamics
#13
Lauren Eichaker, Chengyu Li, Nakesha King, Victoria Pepper, Cameron Best, Ekene Onwuka, Eric Heuer, Kai Zhao, Jonathan Grischkan, Christopher Breuer, Jed Johnson, Tendy Chiang
OBJECTIVES/HYPOTHESIS: Current techniques for airway characterization include endoscopic or radiographic measurements that produce static, two-dimensional descriptions. As pathology can be multilevel, irregularly shaped, and dynamic, minimal luminal area (MLA) may not provide the most comprehensive description or diagnostic metric. Our aim was to examine the utilization of computational fluid dynamics (CFD) for the purpose of defining airway stenosis using an ovine model of tissue-engineered tracheal graft (TETG) implantation...
May 14, 2018: Laryngoscope
https://www.readbyqxmd.com/read/29752540/detecting-mismatches-in-the-phenology-of-cotton-bollworm-larvae-and-cotton-flowering-in-response-to-climate-change
#14
Jian Huang, HongFei Hao
Current evidence suggests that climate change has directly affected the phenology of many invertebrate species associated with agriculture. Such changes in phenology have the potential to cause temporal mismatches between predators and prey and may lead to a disruption in natural pest control ecosystem. Understanding the synchrony between pest insects and host plant responses to climate change is a key step to improve integrated pest management strategies. Cotton bollworm larvae damage cotton, and thus, data from Magaiti County, China, collected during the period of 1990-2015 were analyzed to assess the effects of climate change on cotton bollworm larvae and cotton flowering...
May 11, 2018: International Journal of Biometeorology
https://www.readbyqxmd.com/read/29748668/computational-modeling-and-fluorescence-microscopy-characterization-of-a-two-phase-magnetophoretic-microsystem-for-continuous-flow-blood-detoxification
#15
Jenifer Gómez-Pastora, Cristina González-Fernández, Eusebio Real, Alexander Iles, Eugenio Bringas, Edward P Furlani, Inmaculada Ortiz
Magnetic beads can be functionalized to capture and separate target pathogens from blood for extracorporeal detoxification. The beads can be magnetically separated from a blood stream and collected into a coflowing buffer solution using a two-phase liquid-liquid continuous-flow microfluidic device in the presence of an external field. However, device design and process optimization, i.e. high bead recovery with minimum blood loss or dilution remain a substantial technological challenge. We introduce a CFD-based Eulerian-Lagrangian computational model that enables the rational design and optimization of such systems...
May 11, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29739658/application-of-a-short-term-air-quality-action-plan-in-madrid-spain-under-a-high-pollution-episode-part-ii-assessment-from-multi-scale-modelling
#16
Rafael Borge, Jose Luis Santiago, David de la Paz, Fernando Martín, Jessica Domingo, Cristina Valdés, Beatriz Sánchez, Esther Rivas, Mª Teresa Rozas, Sonia Lázaro, Javier Pérez, Álvaro Fernández
Air pollution continues to be one of the main issues in urban areas. In addition to air quality plans and emission abatement policies, additional measures for high pollution episodes are needed to avoid exceedances of hourly limit values under unfavourable meteorological conditions such as the Madrid's short-term action NO2 protocol. In December 2016 there was a strong atmospheric stability episode that turned out in generalized high NO2 levels, causing the stage 3 of the NO2 protocol to be triggered for the first time in Madrid (29th December)...
May 5, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29738819/use-of-computational-fluid-dynamics-for-improving-freeze-dryers-design-and-process-understanding-part-2-condenser-duct-and-valve-modelling
#17
Daniele L Marchisio, Miquel Galan, Antonello A Barresi
This manuscript shows how computational models, mainly based on Computational Fluid Dynamics (CFD), can be used to simulate different parts of an industrial freeze-drying equipment and to properly design them; in particular in this part the duct connecting the chamber with the condenser, with its valves, is considered, while the chamber design and its effect on drying kinetics have been investigated in Part 1. Such an approach allows a much deeper process understanding and assessment of the critical aspects of lyophilisation...
May 5, 2018: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/29735315/accuracy-and-precision-of-a-plane-wave-vector-flow-imaging-method-in-the-healthy-carotid-artery
#18
Jonas Jensen, Carlos Armando Villagómez Hoyos, Marie Sand Traberg, Jacob Bjerring Olesen, Borislav Gueorguiev Tomov, Ramin Moshavegh, Simon Holbek, Matthias Bo Stuart, Caroline Ewertsen, Kristoffer Lindskov Hansen, Carsten Thomsen, Michael Bachmann Nielsen, Jørgen Arendt Jensen
The objective of the study described here was to investigate the accuracy and precision of a plane wave 2-D vector flow imaging (VFI) method in laminar and complex blood flow conditions in the healthy carotid artery. The approach was to study (i) the accuracy for complex flow by comparing the velocity field from a computational fluid dynamics (CFD) simulation to VFI estimates obtained from the scan of an anthropomorphic flow phantom and from an in vivo scan; (ii) the accuracy for laminar unidirectional flow in vivo by comparing peak systolic velocities from VFI with magnetic resonance angiography (MRA); (iii) the precision of VFI estimation in vivo at several evaluation points in the vessels...
May 4, 2018: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/29733948/predictive-models-of-lyophilization-process-for-development-scale-up-tech-transfer-and-manufacturing
#19
Tong Zhu, Ehab M Moussa, Madeleine Witting, Deliang Zhou, Kushal Sinha, Mario Hirth, Martin Gastens, Sherwin Shang, Nandkishor Nere, Shubha Chetan Somashekar, Alina Alexeenko, Feroz Jameel
Scale-up and technology transfer of lyophilization processes remains a challenge that requires thorough characterization of the laboratory and larger scale lyophilizers. In this study, computational fluid dynamics (CFD) was employed to develop computer-based models of both laboratory and manufacturing scale lyophilizers in order to understand the differences in equipment performance arising from distinct designs. CFD coupled with steady state heat and mass transfer modeling of the vial were then utilized to study and predict independent variables such as shelf temperature and chamber pressure, and response variables such as product resistance, product temperature and primary drying time for a given formulation...
May 4, 2018: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/29733275/noninvasive-estimation-of-pressure-changes-using-2-d-vector-velocity-ultrasound-an-experimental-study-with-in-vivo-examples
#20
Jacob Bjerring Olesen, Carlos Armando Villagomez-Hoyos, Niclas Dechau Moller, Caroline Ewertsen, Kristoffer Lindskov Hansen, Michael Bachmann Nielsen, Bo Bech, Lars Lonn, Marie Sand Traberg, Jorgen Arendt Jensen
A noninvasive method for estimating intravascular pressure changes using 2-D vector velocity is presented. The method was first validated on computational fluid dynamic (CFD) data and with catheter measurements on phantoms. Hereafter, the method was tested in vivo at the carotid bifurcation and at the aortic valve of two healthy volunteers. Ultrasound measurements were performed using the experimental scanner SARUS, in combination with an 8 MHz linear array transducer for experimental scans and a carotid scan, whereas a 3...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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