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https://www.readbyqxmd.com/read/27921372/a-fuzzy-neural-network-sliding-mode-controller-for-vibration-suppression-in-robotically-assisted-minimally-invasive-surgery
#1
Hongqiang Sang, Chenghao Yang, Fen Liu, Jintian Yun, Guoguang Jin
BACKGROUND: It is very important for robotically assisted minimally invasive surgery to achieve a high-precision and smooth motion control. However, the surgical instrument tip will exhibit vibration caused by nonlinear friction and unmodeled dynamics, especially when the surgical robot system is attempting low-speed, fine motion. METHODS: A fuzzy neural network sliding mode controller (FNNSMC) is proposed to suppress vibration of the surgical robotic system. Nonlinear friction and modeling uncertainties are compensated by a Stribeck model, a radial basis function (RBF) neural network and a fuzzy system, respectively...
December 2016: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/27921352/posttraumatic-stress-disorder-associated-with-unexpected-death-of-a-loved-one-cross-national-findings-from-the-world-mental-health-surveys
#2
Lukoye Atwoli, Dan J Stein, Andrew King, Maria Petukhova, Sergio Aguilar-Gaxiola, Jordi Alonso, Evelyn J Bromet, Giovanni de Girolamo, Koen Demyttenaere, Silvia Florescu, Josep Maria Haro, Elie G Karam, Norito Kawakami, Sing Lee, Jean-Pierre Lepine, Fernando Navarro-Mateu, Siobhan O'Neill, Beth-Ellen Pennell, Marina Piazza, Jose Posada-Villa, Nancy A Sampson, Margreet Ten Have, Alan M Zaslavsky, Ronald C Kessler
BACKGROUND: Unexpected death of a loved one (UD) is the most commonly reported traumatic experience in cross-national surveys. However, much remains to be learned about posttraumatic stress disorder (PTSD) after this experience. The WHO World Mental Health (WMH) survey initiative provides a unique opportunity to address these issues. METHODS: Data from 19 WMH surveys (n = 78,023; 70.1% weighted response rate) were collated. Potential predictors of PTSD (respondent sociodemographics, characteristics of the death, history of prior trauma exposure, history of prior mental disorders) after a representative sample of UDs were examined using logistic regression...
December 6, 2016: Depression and Anxiety
https://www.readbyqxmd.com/read/27921189/homogenized-constrained-mixture-models-for-anisotropic-volumetric-growth-and-remodeling
#3
F A Braeu, A Seitz, R C Aydin, C J Cyron
Constrained mixture models for soft tissue growth and remodeling have attracted increasing attention over the last decade. They can capture the effects of the simultaneous presence of multiple constituents that are continuously deposited and degraded at in general different rates, which is important to understand essential features of living soft tissues that cannot be captured by simple kinematic growth models. Recently the novel concept of homogenized constrained mixture models was introduced. It was shown that these models produce results which are very similar (and in certain limit cases even identical) to the ones of constrained mixture models based on multi-network theory...
December 5, 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/27921169/drying-kinetics-of-deformable-and-cracking-nano-porous-gels
#4
J Thiery, E Keita, S Rodts, D Courtier Murias, T Kodger, A Pegoraro, P Coussot
The desiccation of porous materials encompasses a wide range of technological and industrial processes and is acutely sensitive to the hierarchical structure of the porous materials resulting in complex dynamics which are challenging to unravel. Macroscopic observations of the surface and geometry of model colloidal gels during desiccation under controlled air flow highlight the role of crack formation in drying. The density of cracks and their rate of appearance depend on the initial solid fraction of the gels and their adherence to the substrate...
December 2016: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/27921106/quantum-and-classical-inter-cage-hopping-of-hydrogen-molecules-in-clathrate-hydrate-temperature-and-cage-occupation-effects
#5
Christian J Burnham, Zdenek Futera, Niall J English
Building on our previous work (J. Phys. Chem. C, 2016, 120, 16561), using an empirical model we run both classical and path-integral molecular dynamics simulations for a type II clathrate hydrate containing different amounts of guest H2 molecules from 1 to 5 molecules per large cage, with results presented at temperatures of 50, 100 K and 200 K. We present results for the density isosurfaces of the guest molecules at all different occupations and temperatures, showing how the density approaches the perfect tetrahedral structure which has been found for the n = 4 case in which each molecule sits on the vertex of a tetrahedron about the centre of each large cage...
December 6, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27921074/initial-performance-studies-of-a-wearable-brain-positron-emission-tomography-camera-based-on-autonomous-thin-film-digital-geiger-avalanche-photodiode-arrays
#6
Charles R Schmidtlein, James N Turner, Michael O Thompson, Krishna C Mandal, Ida Häggström, Jiahan Zhang, John L Humm, David H Feiglin, Andrzej Krol
Using analytical and Monte Carlo modeling, we explored performance of a lightweight wearable helmet-shaped brain positron emission tomography (PET), or BET camera, based on thin-film digital Geiger avalanche photodiode arrays with Lutetium-yttrium oxyorthosilicate (LYSO) or [Formula: see text] scintillators for imaging in vivo human brain function of freely moving and acting subjects. We investigated a spherical cap BET and cylindrical brain PET (CYL) geometries with 250-mm diameter. We also considered a clinical whole-body (WB) LYSO PET/CT scanner...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/27921010/structural-insights-into-substrate-recognition-by-clostridium-difficile-sortase
#7
Jui-Chieh Yin, Chun-Hsien Fei, Yen-Chen Lo, Yu-Yuan Hsiao, Jyun-Cyuan Chang, Jay C Nix, Yuan-Yu Chang, Lee-Wei Yang, I-Hsiu Huang, Shuying Wang
Sortases function as cysteine transpeptidases that catalyze the covalent attachment of virulence-associated surface proteins into the cell wall peptidoglycan in Gram-positive bacteria. The substrate proteins targeted by sortase enzymes have a cell wall sorting signal (CWSS) located at the C-terminus. Up to date, it is still not well understood how sortases with structural resemblance among different classes and diverse species of bacteria achieve substrate specificity. In this study, we focus on elucidating the molecular basis for specific recognition of peptide substrate PPKTG by Clostridium difficile sortase B (Cd-SrtB)...
2016: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/27920956/grassland-productivity-in-response-to-nutrient-additions-and-herbivory-is-scale-dependent
#8
Erica A H Smithwick, Douglas C Baldwin, Kusum J Naithani
Vegetation response to nutrient addition can vary across space, yet studies that explicitly incorporate spatial pattern into experimental approaches are rare. To explore whether there are unique spatial scales (grains) at which grass response to nutrients and herbivory is best expressed, we imposed a large (∼3.75 ha) experiment in a South African coastal grassland ecosystem. In two of six 60 × 60 m grassland plots, we imposed a scaled sampling design in which fertilizer was added in replicated sub-plots (1 × 1 m, 2 × 2 m, and 4 × 4 m)...
2016: PeerJ
https://www.readbyqxmd.com/read/27920940/3d-printing-in-neurosurgery-a-systematic-review
#9
REVIEW
Michael Randazzo, Jared M Pisapia, Nickpreet Singh, Jayesh P Thawani
BACKGROUND: The recent expansion of three-dimensional (3D) printing technology into the field of neurosurgery has prompted a widespread investigation of its utility. In this article, we review the current body of literature describing rapid prototyping techniques with applications to the practice of neurosurgery. METHODS: An extensive and systematic search of the Compendex, Scopus, and PubMed medical databases was conducted using keywords relating to 3D printing and neurosurgery...
2016: Surgical Neurology International
https://www.readbyqxmd.com/read/27920466/joint-models-for-multiple-longitudinal-processes-and-time-to-event-outcome
#10
Lili Yang, Menggang Yu, Sujuan Gao
Joint models are statistical tools for estimating the association between time-to-event and longitudinal outcomes. One challenge to the application of joint models is its computational complexity. Common estimation methods for joint models include a two-stage method, Bayesian and maximum-likelihood methods. In this work, we consider joint models of a time-to-event outcome and multiple longitudinal processes and develop a maximum-likelihood estimation method using the expectation-maximization (EM) algorithm...
2016: Journal of Statistical Computation and Simulation
https://www.readbyqxmd.com/read/27920368/use-of-the-concordance-index-for-predictors-of-censored-survival-data
#11
Adam R Brentnall, Jack Cuzick
The concordance index is often used to measure how well a biomarker predicts the time to an event. Estimators of the concordance index for predictors of right-censored data are reviewed, including those based on censored pairs, inverse probability weighting and a proportional-hazards model. Predictive and prognostic biomarkers often lose strength with time, and in this case the aforementioned statistics depend on the length of follow up. A semi-parametric estimator of the concordance index is developed that accommodates converging hazards through a single parameter in a Pareto model...
December 5, 2016: Statistical Methods in Medical Research
https://www.readbyqxmd.com/read/27920331/3d-model-analysis-of-ankle-flexion-on-anatomic-reduction-of-a-syndesmotic-injury
#12
Jason M Schon, Jacob D Mikula, Jonathon D Backus, Melanie B Venderley, Grant J Dornan, Robert F LaPrade, Thomas O Clanton
BACKGROUND: The effect of ankle positioning during suture-button fixation for syndesmosis repair on range of motion (ROM) and anatomic reduction has yet to be investigated. The purpose of this cadaveric study was to compare the effects of 3 different ankle positions during suture-button repair on volumetric reduction of the syndesmosis, fibular displacement, and ROM of the ankle using 3-dimensional computed tomography (CT) analysis. The null hypothesis was that ankle position during fixation would not affect syndesmotic volume restoration, fibular displacement, or ROM...
December 5, 2016: Foot & Ankle International
https://www.readbyqxmd.com/read/27919623/assessment-of-the-neutron-dose-field-around-a-biomedical-cyclotron-fluka-simulation-and-experimental-measurements
#13
Angelo Infantino, Gianfranco Cicoria, Giulia Lucconi, Davide Pancaldi, Sara Vichi, Federico Zagni, Domiziano Mostacci, Mario Marengo
In the planning of a new cyclotron facility, an accurate knowledge of the radiation field around the accelerator is fundamental for the design of shielding, the protection of workers, the general public and the environment. Monte Carlo simulations can be very useful in this process, and their use is constantly increasing. However, few data have been published so far as regards the proper validation of Monte Carlo simulation against experimental measurements, particularly in the energy range of biomedical cyclotrons...
December 2, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27919562/impact-of-pre-equilibration-and-diffusion-limited-release-kinetics-on-effluent-concentration-in-column-leaching-tests-insights-from-numerical-simulations
#14
Michael Finkel, Peter Grathwohl
Column leaching tests have become a standard method for assessing leaching of pollutants from materials used, e.g., for road and railway constructions and in landscaping measures. Column tests showed to be practical in laboratories yielding robust and reproducible results. However, considerable uncertainty still exists related particularly to the degree of equilibration of the pore water with the solids during preparation (pre-equilibration) and percolation of the column. We analyse equilibration time scales and sensitivity of concentrations in column leachate with respect to initial conditions in a series of numerical experiments covering a broad spectrum of material and solute properties...
December 2, 2016: Waste Management
https://www.readbyqxmd.com/read/27919430/carbon-dioxide-insufflation-deflects-airborne-particles-from-an-open-surgical-wound-model
#15
P Kokhanenko, G Papotti, J E Cater, A C Lynch, J A van der Linden, C J T Spence
BACKGROUND: Surgical site infections remain a significant burden on healthcare systems and may benefit from new countermeasures. AIM: To assess the merits of open surgical wound CO2 insufflation via a gas diffuser to reduce airborne contamination, and to determine the distribution of CO2 in and over a wound. METHODS: An experimental approach with engineers and clinical researchers was employed to measure the gas flow pattern and motion of airborne particles in a model of an open surgical wound in a simulated theatre setting...
November 21, 2016: Journal of Hospital Infection
https://www.readbyqxmd.com/read/27919417/multidirectional-wss-disturbances-in-stenotic-turbulent-flows-a-pre-and-post-intervention-study-in-an-aortic-coarctation
#16
Magnus Andersson, Jonas Lantz, Tino Ebbers, Matts Karlsson
Wall shear stress (WSS) disturbances are commonly expressed at sites of abnormal flow obstructions and may play an essential role in the pathogenesis of various vascular diseases. In laminar flows these disturbances have recently been assessed by the transverse wall shear stress (transWSS), which accounts for the WSS multidirectionality. Site-specific estimations of WSS disturbances in pulsatile transitional and turbulent type of flows are more challenging due to continuous and unpredictable changes in WSS behavior...
November 28, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27919416/a-3d-model-of-the-achilles-tendon-to-determine-the-mechanisms-underlying-nonuniform-tendon-displacements
#17
Geoffrey G Handsfield, Joshua M Inouye, Laura C Slane, Darryl G Thelen, G Wilson Miller, Silvia S Blemker
The Achilles is the thickest tendon in the body and is the primary elastic energy-storing component during running. The form and function of the human Achilles is complex: twisted structure, intratendinous interactions, and differential motor control from the triceps surae muscles make Achilles behavior difficult to intuit. Recent in vivo imaging of the Achilles has revealed nonuniform displacement patterns that are not fully understood and may result from complex architecture and musculotendon interactions...
November 28, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27919415/implementation-of-a-mfac-based-position-sensorless-drive-for-high-speed-bldc-motors-with-nonideal-back-emf
#18
Haitao Li, Xin Ning, Wenzhuo Li
In order to improve the reliability and reduce power consumption of the high speed BLDC motor system, this paper presents a model free adaptive control (MFAC) based position sensorless drive with only a dc-link current sensor. The initial commutation points are obtained by detecting the phase of EMF zero-crossing point and then delaying 30 electrical degrees. According to the commutation error caused by the low pass filter (LPF) and other factors, the relationship between commutation error angle and dc-link current is analyzed, a corresponding MFAC based control method is proposed, and the commutation error can be corrected by the controller in real time...
December 2, 2016: ISA Transactions
https://www.readbyqxmd.com/read/27919393/business-analysis-for-a-sustainable-multi-stakeholder-ecosystem-for-leveraging-the-electronic-health-records-for-clinical-research-ehr4cr-platform-in-europe
#19
Danielle Dupont, Ariel Beresniak, Mats Sundgren, Andreas Schmidt, John Ainsworth, Pascal Coorevits, Dipak Kalra, Marc Dewispelaere, Georges De Moor
INTRODUCTION: The Electronic Health Records for Clinical Research (EHR4CR) technological platform has been developed to enable the trustworthy reuse of hospital electronic health records data for clinical research. The EHR4CR platform can enhance and speed up clinical research scenarios: protocol feasibility assessment, patient identification for recruitment in clinical trials, and clinical data exchange, including for reporting serious adverse events. Our objective was to seed a multi-stakeholder ecosystem to enable the scalable exploitation of the EHR4CR platform in Europe, and to assess its economic sustainability...
January 2017: International Journal of Medical Informatics
https://www.readbyqxmd.com/read/27919355/model-observational-bridging-study-on-the-effectiveness-of-ezetimibe-on-cardiovascular-morbidity-and-mortality-in-france-a-population-based-study
#20
Jean Ferrières, Jean Dallongeville, Michel Rossignol, Jacques Bénichou, J Jaime Caro, Denis Getsios, Luis Hernandez, Lucien Abenhaim, Lamiae Grimaldi-Bensouda
BACKGROUND: To evaluate the real-life impact of ezetimibe on cardiovascular (CV) morbidity and mortality in France. OBJECTIVE: To estimate the number of non-fatal and fatal CV events that could be prevented and corresponding number of patients needed to treat (NNT) with ezetimibe to prevent one CV event over 5 years. METHODS: Non-interventional 48-month follow-up cohort conducted in hypercholesterolemic patients starting on ezetimibe <3 months at study entry, either as monotherapy or combined with statins...
November 2016: Journal of Clinical Lipidology
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