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https://www.readbyqxmd.com/read/28929446/new-imaging-tools-in-cardiovascular-medicine-computational-fluid-dynamics-and-4d-flow-mri
#1
Keiichi Itatani, Shohei Miyazaki, Tokoki Furusawa, Satoshi Numata, Sachiko Yamazaki, Kazuki Morimoto, Rina Makino, Hiroko Morichi, Teruyasu Nishino, Hitoshi Yaku
Blood flow imaging is a novel technology in cardiovascular medicine and surgery. Today, two types of blood flow imaging tools are available: measurement-based flow visualization including 4D flow MRI (or 3D cine phase-contrast magnetic resonance imaging), or echocardiography flow visualization software, and computer flow simulation modeling based on computational fluid dynamics (CFD). MRI and echocardiography flow visualization provide measured blood flow but have limitations in temporal and spatial resolution, whereas CFD flow calculates the flow according to assumptions instead of flow measurement, and it has sufficiently fine resolution up to the computer memory limit, and it enables even virtual surgery when combined with computer graphics...
September 19, 2017: General Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28929325/computational-fluid-dynamics-cfd-analysis-of-airlift-bioreactor-effect-of-draft-tube-configurations-on-hydrodynamics-cell-suspension-and-shear-rate
#2
Sanjay B Pawar
The biomass productivity of microalgae cells mainly depends on the hydrodynamics of airlift bioreactor (ABR). Thus, the hydrodynamics of concentric tube ABR was initially studied using two-phase three-dimensional CFD simulations with the Eulerian-Lagrangian approach. The performance of ABR (17 L) was examined for different configurations of the draft tube using various drag models such as Grace, Ishii-Zuber, and Schiller-Naumann. The gas holdups in the riser and the downcomer were well predicted using E-L approach...
September 19, 2017: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/28923473/virtual-surgery-for-patients-with-nasal-obstruction-use-of-computational-fluid-dynamics-mecomland-%C3%A2-digbody-%C3%A2-noseland-%C3%A2-to-document-objective-flow-parameters-and-optimise-surgical-results
#3
Manuel A Burgos, Maria Agustina Sevilla García, Enrique Sanmiguel Rojas, Carlos Del Pino, Carlos Fernández Velez, Francisco Piqueras, Francisco Esteban Ortega
INTRODUCTION: Computational fluid dynamics (CFD) is a mathematical tool to analyse airflow. We present a novel CFD software package to improve results following nasal surgery for obstruction. METHODS: A group of engineers in collaboration with otolaryngologists have developed a very intuitive CFD software package called MeComLand®, which uses the patient's cross-sectional (tomographic) images, thus showing in detail results originated by CFD such as airflow distributions, velocity profiles, pressure, or wall shear stress...
September 15, 2017: Acta Otorrinolaringológica Española
https://www.readbyqxmd.com/read/28919576/simulation-of-the-effects-of-oxygen-carriers-and-scaffold-geometry-on-oxygen-distribution-and-cell-growth-in-a-channeled-scaffold-for-engineering-myocardium
#4
Alireza Zehi Mofrad, Shohreh Mashayekhan, Dariush Bastani
This study proposes a mathematical model to evaluate the impact of oxygen carriers and scaffold geometry on oxygen distribution and cell growth in a 3D cardiac construct using computational fluid dynamics (CFD). Flow equations, oxygen balance equation and cell balance equation were solved using special initial and boundary conditions. The modeling results revealed that 55% increase in cardiac cell density occurred by using 6.4% perfluorocarbon oxygen carrier (PFC) compared to pure culture medium without PFC supplementation...
September 14, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/28918876/evaluation-of-potential-substrates-for-restenosis-and-thrombosis-in-overlapped-versus-edge-to-edge-juxtaposed-bioabsorbable-scaffolds-insights-from-a-computed-fluid-dynamic-study
#5
Gianluca Rigatelli, Marco Zuin, Fabio Dell'Avvocata, Paolo Cardaioli, Dobrin Vassiliev, Miroslaw Ferenc, Nguyen Tuan Nghia, Thach Nguyen, Nicholas Foin
BACKGROUND/PURPOSE: Multiple BRSs and specifically the Absorb scaffold (BVS) (Abbott Vascular, Santa Clara, CA USA) have been often used to treat long diffuse coronary artery lesions. We evaluate by a computational fluid dynamic(CFD) study the impact on the intravascular fluid rheology on multiple bioabsorbable scaffolds (BRS) by standard overlapping versus edge-to-edge technique. METHODS/MATERIALS: We simulated the treatment of a real long significant coronary lesion (>70% luminal narrowing) involving the left anterior descending artery (LAD) treated with a standard or edge-to-edge technique, respectively...
August 17, 2017: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/28917579/microcirculation-in-the-murine-liver-a-computational-fluid-dynamic-model-based-on-3d-reconstruction-from-in-vivo-microscopy
#6
Monica Piergiovanni, Elena Bianchi, Giada Capitani, Irene Li Piani, Lucia Ganzer, Luca G Guidotti, Matteo Iannacone, Gabriele Dubini
The liver is organized in hexagonal functional units - termed lobules - characterized by a rather peculiar blood microcirculation, due to the presence of a tangled network of capillaries - termed sinusoids. A better understanding of the hemodynamics that governs liver microcirculation is relevant to clinical and biological studies aimed at improving our management of liver diseases and transplantation. Herein, we built a CFD model of a 3D sinusoidal network, based on in vivo images of a physiological mouse liver obtained with a 2-photon microscope...
September 2, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28903321/alu-based-cell-free-dna-a-novel-biomarker-for-screening-of-gastric-cancer
#7
Chen Qian, Shaoqing Ju, Jing Qi, Jianmei Zhao, Xianjuan Shen, Rongrong Jing, Juan Yu, Li Li, Yingjuan Shi, Lurong Zhang, Zhiwei Wang, Hui Cong
Gastric cancer (GC) is the fourth most common cancer and the second major cause of cancer-related deaths worldwide. In our previous study, a novel and sensitive method for quantifying cell-free DNA (CFD) in human blood was established and tested for its ability to predict patients with tumor. We want to investigate CFD expression in the sera of GC patients in an attempt to explore the clinical significance of CFD in improving the early screening of GC and monitoring GC progression by the branched DNA (bDNA)-based Alu assay...
August 15, 2017: Oncotarget
https://www.readbyqxmd.com/read/28902523/functional-assessment-of-lesion-severity-without-using-the-pressure-wire-coronary-imaging-and-blood-flow-simulation
#8
Michail I Papafaklis, Michail C Mavrogiannis, Panagiotis K Siogkas, Lampros S Lakkas, Christos S Katsouras, Dimitrios I Fotiadis, Lampros K Michalis
Hemodynamic indices derived from measurements with the pressure wire (primarily fractional flow reserve [FFR]) have been established as a reliable tool for assessing coronary stenoses and improving clinical decision making. However, the use of the pressure wire constitutes a hurdle for the universal adoption of physiology-guided patient management. Technological advancements have enabled the large-scale application of blood flow simulation (computational fluid dynamics [CFD]) to medical imaging, thereby enabling the virtual assessment of coronary physiology...
September 19, 2017: Expert Review of Cardiovascular Therapy
https://www.readbyqxmd.com/read/28902139/autonomous-sensors-powered-by-energy-harvesting-from-von-karman-vortices-in-airflow
#9
Marco Demori, Marco Ferrari, Arianna Bonzanini, Pietro Poesio, Vittorio Ferrari
In this paper an energy harvesting system based on a piezoelectric converter to extract energy from airflow and use it to power battery-less sensors is presented. The converter is embedded as a part of a flexure beam that is put into vibrations by von Karman vortices detached from a bluff body placed upstream. The vortex street has been investigated by Computational Fluid Dynamics (CFD) simulations, aiming at assessing the vortex shedding frequency as a function of the flow velocity. From the simulation results the preferred positioning of the beam behind the bluff body has been derived...
September 13, 2017: Sensors
https://www.readbyqxmd.com/read/28900625/direct-assessment-of-wall-shear-stress-by-signal-intensity-gradient-from-time-of-flight-magnetic-resonance-angiography
#10
Kap-Soo Han, Sang Hyuk Lee, Han Uk Ryu, Se-Hyoung Park, Gyung-Ho Chung, Young I Cho, Seul-Ki Jeong
The aim of the study was to calculate the arterial wall signal intensity gradient (SIG) from time-of-flight MR angiography (TOF-MRA) and represent arterial wall shear stress. We developed a new algorithm that uses signal intensity (SI) of a TOF-MRA to directly calculate the signal intensity gradient (SIG). The results from our phantom study showed that the TOF-MRA SIG could be used to distinguish the magnitude of blood flow rate as high (mean SIG ± SD, 2.2 ± 0.4 SI/mm for 12.5 ± 2.3 L/min) and low (0...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28894833/ethmoidectomy-combined-with-superior-meatus-enlargement-increases-olfactory-airflow
#11
Hironobu Nishijima, Kenji Kondo, Tsutomu Nomura, Tatsuya Yamasoba
OBJECTIVES: The relationship between a particular surgical technique in endoscopic sinus surgery (ESS) and airflow changes in the post-operative olfactory region has not been assessed. The present study aimed to compare olfactory airflow after ESS between conventional ethmoidectomy and ethmoidectomy with superior meatus enlargement, using virtual ESS and computational fluid dynamics (CFD) analysis. STUDY DESIGN: Prospective computational study. MATERIALS AND METHODS: Nasal computed tomography images of four adult subjects were used to generate models of the nasal airway...
August 2017: Laryngoscope Investigative Otolaryngology
https://www.readbyqxmd.com/read/28894819/computational-modelling-of-cough-function-and-airway-penetrant-behavior-in-patients-with-disorders-of-laryngeal-function
#12
Bari Hoffman Ruddy, Don Nadun Kuruppumullage, Giselle Carnaby, Michael Crary, Jeffery Lehman, Olusegun J Ilegbusi
OBJECTIVE/HYPOTHESIS: Patients with laryngeal disorders often exhibit changes to cough function contributing to aspiration episodes. Two primary cough variables (peak cough flow: PCF and compression phase duration: CPD) were examined within a biomechanical model to determine their impact on characteristics that impact airway compromise. STUDY DESIGN: Computational study. METHODS: A Computational Fluid Dynamics (CFD) technique was used to simulate fluid flow within an upper airway model reconstructed from patient CT images...
February 2017: Laryngoscope Investigative Otolaryngology
https://www.readbyqxmd.com/read/28890987/impact-of-patient-specific-inflow-velocity-profile-on-hemodynamics-of-the-thoracic-aorta
#13
Pouya Youssefi, Alberto Gomez, Christopher Arthurs, Rajan Sharma, Marjan Jahangiri, Alberto Figueroa
Background-Computational fluid dynamics (CFD) provides a non-invasive method to functionally assess aortic hemodynamics. The thoracic aorta has an anatomically complex inlet comprising of the aortic valve, which is highly prone to different morphologies and pathologies. We investigated the effect of using patient-specific inflow velocity profiles compared to idealised profiles based on the patient's flow waveform. Methods-A healthy 31yo with a normally functioning tricuspid aortic valve (subject A), and a 52yo with a bicuspid aortic valve, aortic valvular stenosis and dilated ascending aorta (subject B) were studied...
September 11, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28890701/high-fat-high-sugar-diet-reduces-voluntary-wheel-running-in-mice-independent-of-sex-hormone-involvement
#14
Heather L Vellers, Ayland C Letsinger, Nicholas R Walker, Jorge Z Granados, J Timothy Lightfoot
Introduction: Indirect results in humans suggest that chronic overfeeding decreases physical activity with few suggestions regarding what mechanism(s) may link overfeeding and decreased activity. The primary sex hormones are known regulators of activity and there are reports that chronic overfeeding alters sex hormone levels. Thepurpose of this study was to determine if chronic overfeeding altered wheel running through altered sex hormone levels. Materials and Methods: C57BL/6J mice were bred and the pups were weaned at 3-weeks of age and randomly assigned to either a control (CFD) or high fat/high sugar (HFHS) diet for 9-11 weeks depending on activity analysis...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28887805/quantitative-analysis-of-effects-of-hemodynamic-stress-on-temporal-variations-of-cardiac-phases-in-models-of-human-carotid-bulbs
#15
Tatsunori Saho, Hideo Onishi
In this study, we evaluated the hemodynamics of carotid artery models with carotid bulbs of various sizes using computational fluid dynamics (CFD) and the Fluent CFD software. The oscillatory shear index (OSI) and flow velocity distribution were evaluated in carotid models without a carotid bulb and with carotid bulbs of known geometry (major axis of 10, 11, 12, 13, and 14 mm; carotid bifurcation angle of 50°). Furthermore, the diameters of the common carotid artery, the external carotid artery, and the internal carotid artery were defined as 7...
September 8, 2017: Radiological Physics and Technology
https://www.readbyqxmd.com/read/28882269/the-construction-face-database-codifying-the-niosh-face-reports
#16
Xiuwen Sue Dong, Julie A Largay, Xuanwen Wang, Chris Trahan Cain, Nancy Romano
INTRODUCTION: The National Institute for Occupational Safety and Health (NIOSH) has published reports detailing the results of investigations on selected work-related fatalities through the Fatality Assessment and Control Evaluation (FACE) program since 1982. METHOD: Information from construction-related FACE reports was coded into the Construction FACE Database (CFD). Use of the CFD was illustrated by analyzing major CFD variables. RESULTS: A total of 768 construction fatalities were included in the CFD...
September 2017: Journal of Safety Research
https://www.readbyqxmd.com/read/28880814/investigation-of-full-scale-ozonation-at-a-municipal-wastewater-treatment-plant-using-a-toxicity-based-evaluation-concept
#17
Fabian Itzel, Linda Gehrmann, Helena Bielak, Paul Ebersbach, Andrea Boergers, Heinrich Herbst, Christian Maus, Anne Simon, Elke Dopp, Monika Hammers-Wirtz, Torsten C Schmidt, Jochen Tuerk
Effluents from municipal wastewater treatment plants (WWTPs) are known to be point sources of micropollutants for surface waters. The aim of this study was to examine a reconstructed full-scale ozonation equipped with a pump-injector system for ozone (O3) dosage and a fluidized moving-bed reactor as biological posttreatment at a municipal WWTP utilizing an effect-directed approach. This approach consists of chemical analysis in combination with toxicological tests for the assessment of treatment efficiency of the plant...
September 7, 2017: Journal of Toxicology and Environmental Health. Part A
https://www.readbyqxmd.com/read/28877965/tests-of-the-sorption-and-olfactory-fovea-hypotheses-in-the-mouse
#18
David Michael Coppola, Brittaney E Ritchie, Brent A Craven
The spatial distribution of receptors within sensory epithelia (e.g. retina and skin) is often markedly non-uniform to gain efficiency in information capture and neural processing. By contrast, odors, unlike visual and tactile stimuli, have no obvious spatial dimension. What need then could there be for either nearest-neighbor relationships or non-uniform distributions of receptor cells in the olfactory epithelium (OE)? Adrian (1942; 1950) provided the only widely debated answer to this question when he posited that the physical properties of odors, such as volatility and water solubility, determine a spatial pattern of stimulation across the OE that could aid odor discrimination...
September 6, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28864895/the-role-of-production-of-adipsin-and-leptin-in-the-development-of-insulin-resistance-in-patients-with-abdominal-obesity
#19
M A Vasilenko, E V Kirienkova, D A Skuratovskaia, P A Zatolokin, N I Mironyuk, L S Litvinova
We investigated the tissue-specific features of the production of adipokines (leptin and adipsin) by adipose tissue in obese patients depending on the degree of obesity and the state of carbohydrate metabolism. An increase in the content of adipsin and leptin in the blood plasma was found. In patients with varying degrees of obesity with and without type 2 diabetes mellitus (DM 2), we determined the level of tissue-specific expression of LEP and CFD genes encoding leptin and adipsin, respectively. The contribution of different adipose tissue depots to the blood plasma level of adipsin and leptin in obese patients with and without DM 2 was established...
July 2017: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28859253/flow-features-and-device-induced-blood-trauma-in-cf-vads-under-a-pulsatile-blood-flow-condition-a-cfd-comparative-study
#20
Zengsheng Chen, Sofen K Jena, Guruprasad A Giridharan, Steven C Koenig, Mark S Slaughter, Bartley P Griffith, Zhongjun J Wu
In this study, the flow features and device-associated blood trauma in four clinical ventricular assist devices (VADs) (two implantable axial VADs, one implantable centrifugal VAD, and one extracorporeal VAD) were computationally analyzed under clinically relevant pulsatile flow conditions. The four VADs were operated at fixed pump speed at a mean rate of 4.5 L/min. Mean pressure difference, wall shear stress (WSS), volume distribution of scalar shear stress (SSS), and shear-induced hemolysis index (HI) were derived from the flow field of each VAD and were compared...
August 31, 2017: International Journal for Numerical Methods in Biomedical Engineering
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