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https://www.readbyqxmd.com/read/28227937/effects-of-tuning-conditions-on-near-field-of-mri-transmit-birdcage-coil-at-64-mhz
#1
Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov
This study investigates how the tuning conditions of a 64 MHz / 1.5 T radio frequency (RF) birdcage coil modeled with an RF circuit and 3D electromagnetic co-simulation affect the electric and magnetic near-field distribution. Four models were implemented with different tuning conditions and difference between numerical results and measurements was evaluated. The results show that the simulated near-field depends significantly on coil tuning conditions, especially in volumes close to the ASTM phantom walls...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227677/multipoint-temperature-monitoring-in-liver-undergoing-computed-tomography-guided-radiofrequency-ablation-with-fiber-bragg-grating-probes
#2
P Saccomandi, E Schena, M Diana, F M Di Matteo, G Costamagna, J Marescaux, P Saccomandi, E Schena, M Diana, F M Di Matteo, G Costamagna, J Marescaux, F M Di Matteo, J Marescaux, E Schena, M Diana, G Costamagna, P Saccomandi
In this work, we investigated the temperature increment experienced by biological tissue during radiofrequency ablation (RFA). The measurements were performed by using two custom-made thermal probes based on fiber optic sensors (fiber Bragg gratings, FBGs). The two probes embed a total of 9 FBGs. Experiments were performed during RFA of an ex vivo healthy porcine liver. The RFA heating module was equipped with 5 thermocouples. Results show that the temperature increment close to the applicator (i.e., 0.6 cm-0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227286/indirect-measurement-of-the-carotid-arterial-pressure-from-vibrocardiographic-signal-calibration-of-the-waveform-and-comparison-with-photoplethysmographic-signal
#3
L Casacanditella, G Cosoli, S Casaccia, E P Tomasini, L Scalise, L Casacanditella, G Cosoli, S Casaccia, E P Tomasini, L Scalise, G Cosoli, S Casaccia, E P Tomasini, L Casacanditella, L Scalise
The detection of arterial Blood Pressure waveform provides important information about the subject health status. Laser Doppler Vibrometry (LDV) is a non-contact technique with high sensitivity able to detect mechanical movements of the arterial wall; several previous studies have shown that LDV is able to characterize cardiac activity. Photoplethysmogram (PPG) quantifies the digital volume artery pulse, which has been demonstrated to be closely related to the pressure signal measured by an arterial tonometer...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227222/hemodynamic-effects-from-coil-distribution-with-realistic-coil-models-in-an-aneurysm
#4
Soichiro Fujimura, Hiroyuki Takao, Takashi Suzuki, Chihebeddine Dahmani, Hiroya Mamori, Makoto Yamamoto, Yuichi Murayama, Soichiro Fujimura, Hiroyuki Takao, Takashi Suzuki, Chihebeddine Dahmani, Hiroya Mamori, Makoto Yamamoto, Yuichi Murayama, Makoto Yamamoto, Hiroya Mamori, Soichiro Fujimura, Takashi Suzuki, Yuichi Murayama, Chihebeddine Dahmani, Hiroyuki Takao
Because of its minimal invasiveness, coil embolization has become a popular way to treat aneurysms. The main problem with this method, however, is the poor understanding of the hemodynamics in the aneurysm after coil embolization. To improve this situation, we used a finite element method and computational fluid dynamics to investigate how hemodynamic parameters depend on the spatial distribution of coils. A basic model of an internal carotid artery aneurysm was created, and six realistic coil models were considered for the coil geometry...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226721/overcoming-spatio-temporal-limitations-using-dynamically-scaled-in-vitro-pc-mri-a-flow-field-comparison-to-true-scale-computer-simulations-of-idealized-stented-and-patient-specific-left-main-bifurcations
#5
Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Stuart Norris, Brett Cowan, Pau Medrano-Gracia, Kathleen Gilbert, Mark Webster, Alistair Young, Susann Beier, John Cater, John Ormiston
The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226427/intermittent-control-of-unstable-multivariate-systems-with-uncertain-system-parameters
#6
I Loram, R Cunningham, J Zenzeri, H Gollee, I Loram, R Cunningham, J Zenzeri, H Gollee, J Zenzeri, R Cunningham, I Loram, H Gollee
Multivariable intermittent control (MIC) combines stability with flexibility in the control of unstable systems. Using an underlying continuous-time optimal control design, MIC uses models of the physical system to generate multivariate open-loop control signals between samples of the observed state. Using accurate model values of physical system parameters, stability of the closed loop system is not dependent upon sample interval. Here we consider the sensitivity of MIC to inaccurate model values of system parameters...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225496/impact-of-nasal-symptoms-on-the-evaluation-of-asthma-control
#7
Chien-Chia Huang, Po-Hung Chang, Pei-Wen Wu, Chun-Hua Wang, Chia-Hsiang Fu, Chi-Che Huang, Hsiao-Jung Tseng, Ta-Jen Lee
The united airways concept suggests that patients with asthma typically exhibit parallel inflammation in the upper airway. The resulting nasal symptoms should reduce quality of life and substantially affect the evaluation of asthma control among these patients. This study aimed to assess the association of nasal symptoms with the evaluation of asthma control.Fifty-eight patients with asthma and persistent nasal symptoms were prospectively recruited for evaluations of their sinonasal symptoms and asthma control in a cross-sectional study from August 2013 to June 2016...
February 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28225355/assessing-cardiac-function-from-total-variation-regularized-4-d-c-arm-ct-in-the-presence-of-angular-undersampling
#8
Oliver Taubmann, Viktor Haase, Guenter Lauritsch, Yefeng Zheng, Gregor Krings, Joachim Hornegger, Andreas Maier
Time-resolved tomographic cardiac imaging using an angiographic C-arm device may support clinicians during minimally invasive therapy by enabling a thorough analysis of the heart function directly in the catheter laboratory. However, clinically feasible acquisition protocols entail a highly challenging reconstruction problem which suffers from sparse angular sampling of the trajectory. Compressed sensing theory promises that useful images can be recovered despite massive undersampling by means of sparsity-based regularization...
February 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28223187/deepnat-deep-convolutional-neural-network-for-segmenting-neuroanatomy
#9
Christian Wachinger, Martin Reuter, Tassilo Klein
We introduce DeepNAT, a 3D Deep convolutional neural network for the automatic segmentation of NeuroAnaTomy in T1-weighted magnetic resonance images. DeepNAT is an end-to-end learning-based approach to brain segmentation that jointly learns an abstract feature representation and a multi-class classification. We propose a 3D patch-based approach, where we do not only predict the center voxel of the patch but also neighbors, which is formulated as multi-task learning. To address a class imbalance problem, we arrange two networks hierarchically, where the first one separates foreground from background, and the second one identifies 25 brain structures on the foreground...
February 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/28221811/deformation-localisation-in-molecular-layers-constrained-between-self-assembled-au-nanoparticles
#10
Guillaume Copie, Moussa Biaye, Heinrich Diesinger, Thierry Mélin, Christophe Krzeminski, Fabrizio Cleri
The localised deformation of molecular monolayers constrained between the spherical surfaces of Au nanoparticles is studied by means of molecular dynamics simulations. Alkyl or polyethylene glycol long-chain molecules were homogeneously distributed over the curved Au surface, pushed against each other by repeated cycles of force relaxation and constant-volume equilibration, at temperatures increasing from 50 to 300K, before being slowly quenched down to near-zero temperature. Plots of minimum configurational energy can be obtained as a function of the nanoparticle distance, according to different directions of approach; therefore, such simulations describe a range of deformations, from perfectly uniaxial compression, to a combination of compression and shear...
February 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28221809/accommodating-high-transformation-strains-in-battery-electrodes-via-formation-of-nanoscale-intermediate-phases-operando-investigation-of-olivine-nafepo4
#11
Kai Xiang, Wenting Xing, Dorthe Bomholdt Ravnsbæk, Liang Hong, Ming Tang, Zheng Li, Kamila M Wiaderek, Olaf J Borkiewicz, Karena W Chapman, Peter J Chupas, Yet-Ming Chiang
Virtually all intercalation compounds exhibit significant changes in unit cell volume as the working ion concentration varies. NaxFePO4 (0<x<1, NFP) olivine, of interest as a cathode for sodium-ion batteries, is a model for topotactic, high strain systems as it exhibits one of the largest discontinuous volume changes (~17% by volume) during its first-order transition between two otherwise isostructural phases. Using synchrotron radiation powder X-ray diffraction (PXD) and pair distribution function (PDF) analysis, we discover a new strain-accommodation mechanism wherein an amorphous phase forms to buffer the large lattice mismatch between primary phases...
February 21, 2017: Nano Letters
https://www.readbyqxmd.com/read/28221152/-percutaneous-nephrolithotomy-pcnl-conditions-for-a-safe-performance
#12
Paúl Antonio Escovar Díaz, Paúl Ernesto Escovar La Riva, Fernando Paúl Rodríguez Escovar, María Elvira Escovar López, María Ximena Escovar López, Mario Ramón Campins Arias, Alejandro Franco
OBJECTIVE: To describe the PCNL technique addressing those conditions that enable us to perform the procedure with maximum patient's safety without losing focus on the objective of lithiasis resolution. METHODS: Based on our experience, accumulated with time, and the constant update of the endourological techniques we treat those issues in relation to PCNL from the efficiency, efficacy and effectiveness perspective. To consider them involves the successful performance of the technique, with complications prevention and taking cost-efficiency into account...
January 2017: Archivos Españoles de Urología
https://www.readbyqxmd.com/read/28220079/muro-neuro-urodynamics-a-review-of-the-functional-assessment-of-mouse-lower-urinary-tract-function
#13
REVIEW
Hiroki Ito, Anthony E Pickering, Yasuhiko Igawa, Anthony J Kanai, Christopher H Fry, Marcus J Drake
Background: Mouse urodynamic tests are fundamental to understanding normal lower urinary tract (LUT) function. These experiments also contribute to our understanding of neurological dysfunction, pathophysiological processes, and potential mechanisms of therapy. Objectives: Systematic assessment of published evidence on urodynamics, advantages and limitations of different urodynamic measurements in mice, and consideration of potential implications for the clinical field. Methods: A search using specific search-terms for urodynamic studies and mice was conducted on PubMed (from inception to 1 July 2016)...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28218613/first-experimental-comparison-between-the-cartesian-and-the-lissajous-trajectory-for-magnetic-particle-imaging
#14
Franziska Werner, Nadine Gdaniec, Tobias Knopp
Magnetic Particle Imaging (MPI) is a quantitative imaging modality that allows to determine the distribution of superparamagnetic nanoparticles. Sampling is achieved by moving a field-free point (FFP) along a specific trajectory through the volume of interest. The magnetic material that lies along the path or in the close vicinity of the FFP changes its magnetization and induces a voltage in surrounding receive coils. Various trajectories for the FFP are conceivable, but most experimental MPI scanners either use a Cartesian or a Lissajous sampling trajectory...
February 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28217768/phased-peristaltic-micropumping-for-continuous-sampling-and-hardcoded-droplet-generation
#15
Adrian M Nightingale, Gareth W H Evans, Peixiang Xu, Byung Jae Kim, Sammer-Ul Hassan, Xize Niu
Droplet microfluidics has recently emerged as a new engineering tool for biochemical analysis of small sample volumes. Droplet generation is most commonly achieved by introducing aqueous and oil phases into a T-junction or a flow focusing channel geometry. This method produces droplets that are sensitive to changes in flow conditions and fluid composition. Here, we present an alternative approach using a simple peristaltic micropump to deliver the aqueous and oil phases in antiphase pulses resulting in a robust "chopping"-like method of droplet generation...
February 20, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28216929/outcomes-of-transurethral-resection-and-holmium-laser-enucleation-in-more-than-60-g-of-prostate-a-prospective-randomized-study
#16
Ankur Jhanwar, Rahul J Sinha, Ankur Bansal, Gaurav Prakash, Kawaljit Singh, Vishwajeet Singh
AIM: Transurethral resection of prostate (TURP) is considered a gold standard surgical procedure. The management of benign prostatic hyperplasia (BPH) has undergone tremendous change in recent years and shifted from open to minimal invasive procedure. With the advancement in technology and skills of surgeons, lasers have been used more liberally, particularly holmium laser. Holmium laser enucleation of prostate (HoLEP) is seen as close rival of TURP. The objective if this study is to observe long- and short-term outcomes of transurethral resection and holmium laser enucleation in the prostate of more than 60 g...
January 2017: Urology Annals
https://www.readbyqxmd.com/read/28213985/capillary-dynamics-driven-by-molecular-self-layering
#17
Pingkeng Wu, Alex Nikolov, Darsh Wasan
Capillary dynamics is a ubiquitous everyday phenomenon. It has practical applications in diverse fields, including ink-jet printing, lab-on-a-chip, biotechnology, and coating. Understanding capillary dynamics requires essential knowledge on the molecular level of how fluid molecules interact with a solid substrate (the wall). Recent studies conducted with the surface force apparatus (SFA), atomic force microscope (AFM), and statistical mechanics simulation revealed that molecules/nanoparticles confined into the film/wall surfaces tend to self-layer into 2D layer/s and even 2D in-layer with increased confinement and fluid volume fraction...
February 10, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28212161/hearing-impairment-and-the-amelioration-of-avoidable-medical-error-a-cross-sectional-survey
#18
Patrick Henn, Colm OʼTuathaigh, Darrelle Keegan, Simon Smith
OBJECTIVES: Hearing loss contributes to suboptimal medical treatment. We investigated the nature and magnitude of potential health-care harm of hearing loss alone on a patient's understanding of medical consultations, investigations, and treatments of health conditions unrelated to their hearing loss. METHODS: A cross-sectional, questionnaire-based design of a convenience sample of students with hearing loss, registered with the institutional disability support service in 8 Irish and 15 UK third-level institutions...
February 16, 2017: Journal of Patient Safety
https://www.readbyqxmd.com/read/28209577/feasibility-of-flat-panel-detector-ct-in-perfusion-assessment-of-brain-arteriovenous-malformations-initial-clinical-experience
#19
M Garcia, T W Okell, M Gloor, M A Chappell, P Jezzard, O Bieri, J V Byrne
The different results from flat panel detector CT in various pathologies have provoked some discussion. Our aim was to assess the role of flat panel detector CT in brain arteriovenous malformations, which has not yet been assessed. Five patients with brain arteriovenous malformations were studied with flat panel detector CT, DSC-MR imaging, and vessel-encoded pseudocontinuous arterial spin-labeling. In glomerular brain arteriovenous malformations, perfusion was highest next to the brain arteriovenous malformation with decreasing values with increasing distance from the lesion...
February 16, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28209433/surface-runoff-and-subsurface-tile-drain-losses-of-neonicotinoids-and-companion-herbicides-at-edge-of-field
#20
François Chrétien, Isabelle Giroux, Georges Thériault, Patrick Gagnon, Julie Corriveau
With their application as seed coatings, the use of neonicotinoid insecticides increased dramatically during the last decade. They are now frequently detected in aquatic ecosystems at concentrations susceptible to harm aquatic invertebrates at individual and population levels. This study intent was to document surface runoff and subsurface tile drain losses of two common neonicotinoids (thiamethoxam and clothianidin) compared to those of companion herbicides (atrazine, glyphosate, S-metolachlor and mesotrione) at the edge of a 22...
February 13, 2017: Environmental Pollution
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