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https://www.readbyqxmd.com/read/28227661/parameter-optimization-of-pseudo-rigid-body-models-of-mri-actuated-catheters
#1
Tipakorn Greigarn, Taoming Liu, M Cenk Cavusoglu, Tipakorn Greigarn, Taoming Liu, M Cenk Cavusoglu, Taoming Liu, Tipakorn Greigarn, M Cenk Cavusoglu
Simulation and control of a system containing compliant mechanisms such as cardiac catheters often incur high computational costs. One way to reduce the costs is to approximate the mechanisms with Pseudo-Rigid-Body Models (PRBMs). A PRBM generally consists of rigid links connected by spring-loaded revolute joints. The lengths of the rigid links and the stiffnesses of the springs are usually chosen to minimize the tip deflection differences between the PRBM and the compliant mechanism. In most applications, only the relationship between end load and tip deflection is considered...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226685/tracking-of-the-anterior-mitral-leaflet-in-echocardiographic-sequences-using-active-contours
#2
Malik Saad Sultan, Nelson Martins, Diana Veiga, Manuel Joao Ferreira, Miguel Tavares Coimbra, Malik Saad Sultan, Nelson Martins, Diana Veiga, Manuel Joao Ferreira, Miguel Tavares Coimbra, Diana Veiga, Nelson Martins, Malik Saad Sultan, Miguel Tavares Coimbra, Manuel Joao Ferreira
Echocardiography assessment of cardiac valves plays a vital role in the diagnosis of rheumatic heart disease. In the vast majority of cases, the mitral valve gets affected, leading to the thickening of its leaflets that may result in the fusion of their tips. This changes the appearance and reduces the mobility of the leaflets, which also reduce the heart efficiency. Quantifying such parameters provides diagnostic insight. To achieve that, the first step is to identify and then track fast moving leaflets. This work is focused on Anterior Mitral Leaflet (AML) tracking...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28223775/a-comparison-of-three-different-corneal-marking-methods-used-to-determine-cyclotorsion-in-the-horizontal-meridian
#3
Hung-Yuan Lin, Yi-Ting Fang, Ya-Jung Chuang, Justin N Karlin, Hsin-Yang Chen, Szu-Yuan Lin, Pi-Jung Lin, Ming Chen
During toric intraocular lens (IOL) implantation, surgeons must take particular care to ensure that inaccurate preoperative measurement and intraoperative misalignment do not cause unexpected postoperative residual astigmatism. This retrospective, comparative case series study aimed to analyze the rotational deviation, or cyclotorsion, of three corneal marking methods: VERION digital marker (VDM; reference), horizontal slit beam marking (HSBM), and subjective direct visual marking (SDVM) on the table (using a bevel knife tip)...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28222759/development-and-assessment-of-a-hand-assist-device-gripit
#4
Byungchul Kim, Hyunki In, Dae-Young Lee, Kyu-Jin Cho
BACKGROUND: Although various hand assist devices have been commercialized for people with paralysis, they are somewhat limited in terms of tool fixation and device attachment method. Hand exoskeleton robots allow users to grasp a wider range of tools but are heavy, complicated, and bulky owing to the presence of numerous actuators and controllers. The GRIPIT hand assist device overcomes the limitations of both conventional devices and exoskeleton robots by providing improved tool fixation and device attachment in a lightweight and compact device...
February 21, 2017: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/28218853/new-information-on-the-hydrophobic-interaction-revealed-by-frequency-modulation-afm
#5
Itai Schlesinger, Uri Sivan
Using an ultra-high resolution AFM operated in frequency modulation mode we extend existing measurements of the force acting between hydrophobic surfaces immersed in water in three essential ways. (1) The measurement range, which was previously limited to distances longer than 2-3 nanometers, is extended to cover all distances, down to contact. The measurements disclose that the long-range attraction observed also by conventional techniques, turns at distances shorter than 1-2 nanometers into pronounced repulsion...
February 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28213934/transverse-process-anatomy-as-a-guide-to-vertebral-artery-exposure-during-anterior-cervical-spine-approach-a-cadaveric-study
#6
Ali Nourbakhsh, Jinping Yang, Howard McMahan, Kim Garges
INTRODUCTION: Safe exposure of the vertebral artery (VA) is needed during resection of tumors close to the artery and during repair of lacerations. We defined the anatomy of the anterior root of each transverse process (TP) from C3 to C6 for identification and exposure of the VA during the anterior approach. MATERIALS AND METHODS: We examined the anatomy of the TP and assessed two approaches for safe identification of the VA, lateral to medial and medial to lateral dissection of the TP, in 20 cadavers...
February 18, 2017: Clinical Anatomy
https://www.readbyqxmd.com/read/28211276/tuning-the-pseudospin-polarization-of-graphene-by-a-pseudo-magnetic-field
#7
Alexander Georgi, Peter Nemes-Incze, Ramon Carrillo-Bastos, Daiara Faria, Silvia Viola Kusminskiy, Dawei Zhai, Martin Schneider, Dinesh Subramaniam, Torge Mashoff, Nils Michael Freitag, Marcus Liebmann, Marco Pratzer, Ludger Wirtz, Colin R Woods, Roman Vladislavovich Gorbachev, Yang Cao, Kostya S Novoselov, Nancy Sandler, Markus Morgenstern
One of the intriguing characteristics of honeycomb lattices is the appearance of a pseudo-magnetic field as a result of mechanical deformation. In the case of graphene, the Landau quantization resulting from this pseudo-magnetic field has been measured using scanning tunneling microscopy. Here we show that a signature of the pseudo-magnetic field is a local sublattice symmetry breaking observable as a redistribution of the local density of states. This can be interpreted as a polarization of graphene's pseudospin due to a strain induced pseudo-magnetic field, in analogy to the alignment of a real spin in a magnetic field...
February 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28211116/ac-dielectrophoretic-manipulation-and-electroporation-of-vaccinia-virus-using-carbon-nanoelectrode-arrays
#8
Foram Ranjeet Madiyar, Sherry Basset, Omer Farooq, Stefan Rothenburg, Christopher Culbertson, Jun Li
This paper reports the capture and detection of vaccinia virus particles based on AC dielectrophoresis (DEP) and electrochemical impedance measurements employing an embedded vertically aligned carbon nanofiber (VACNF) nanoelectrode array (NEA) versus a macroscopic indium-tin-oxide (ITO) transparent electrode in a "points-and-lid" configuration. The nano-DEP device was fabricated by bonding two SU-8 covered electrodes patterned using photolithography. The bottom electrode contains a 200 × 200 μm(2) active region on a randomly distributed NEA and the top electrode contains a microfluidic channel in SU-8 spin-coated on ITO to guide the flow of the virus solution...
February 17, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28209731/transport-of-fungal-rab11-secretory-vesicles-involves-myosin-5-dynein-dynactin-p25-and-kinesin-1-and-is-independent-of-kinesin-3
#9
Miguel A Peñalva, Jun Zhang, Xin Xiang, Areti Pantazopoulou
Hyphal tip cells of the fungus Aspergillus nidulans are useful to study long-range intracellular traffic. Post-Golgi secretory vesicles (SVs) containing the RAB11 orthologue RabE engage myosin-5 as well as plus-end- and minus-end-directed microtubule motors, providing an experimental system to investigate the interplay between microtubule and actin motors acting on the same cargo. By exploiting the fact that depolymerization of F-actin 'unleashes' SVs focused at the apex by myosin-5 to microtubule-dependent motors, we establish that the minus-end directed transport of SVs requires the dynein/dynactin supercomplex...
February 16, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28204846/regulation-of-end-binding-protein-eb1-in-the-control-of-microtubule-dynamics
#10
REVIEW
Anne Nehlig, Angie Molina, Sylvie Rodrigues-Ferreira, Stéphane Honoré, Clara Nahmias
The regulation of microtubule dynamics is critical to ensure essential cell functions, such as proper segregation of chromosomes during mitosis or cell polarity and migration. End-binding protein 1 (EB1) is a plus-end-tracking protein (+TIP) that accumulates at growing microtubule ends and plays a pivotal role in the regulation of microtubule dynamics. EB1 autonomously binds an extended tubulin-GTP/GDP-Pi structure at growing microtubule ends and acts as a molecular scaffold that recruits a large number of regulatory +TIPs through interaction with CAP-Gly or SxIP motifs...
February 15, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/28203512/unusual-volar-pulp-location-of-glomus-tumor
#11
Ian A Rosner, Anne E Argenta, Kia M Washington
Glomus tumors are benign, painful growths originating from glomus bodies and comprise just 1% of tumors arising in the hand, with fewer than 10% in the volar pulp of digits. Hallmark symptoms of glomus tumors include hypersensitivity to cold, heightened pinprick sensitivity, and paroxysmal pain. We report a 72-year-old, right-hand dominant man who presented with pain in the left middle finger, localized to the tip. The fingertip was incredibly sensitive to touch, and his pain increased at night. He reported no recollection of trauma...
January 2017: Plastic and Reconstructive Surgery. Global Open
https://www.readbyqxmd.com/read/28202967/trump-a-confluence-of-tipping-points
#12
Robert Costanza
No abstract text is available yet for this article.
February 15, 2017: Nature
https://www.readbyqxmd.com/read/28199993/intraoperative-thresholds-for-capsular-stimulation-are-reliable-for-chronic-pallidal-deep-brain-stimulation-in-dystonia
#13
René Reese, Martin M Reich, Daniela Falk, Günther Deuschl, H Maximilian Mehdorn, Jens Volkmann
BACKGROUND: The threshold current for inducing muscle contractions by stimulation of pyramidal tract fibres adjacent to the globus pallidus internus (GPi) is, besides microelectrode recordings for the determination of nuclear boundaries, currently the only neurophysiological marker for intraoperative refinement of the anatomically planned target point for pallidal deep brain stimulation (GPi-DBS) in dystonia. OBJECTIVES: To determine the relationship between intraoperative thresholds for muscle contractions under general anaesthesia and postoperative thresholds in GPi-DBS...
February 16, 2017: Stereotactic and Functional Neurosurgery
https://www.readbyqxmd.com/read/28195001/design-and-analysis-of-a-tendon-based-computed-tomography-compatible-robot-with-remote-center-of-motion-for-lung-biopsy
#14
Yunpeng Yang, Shan Jiang, Zhiyong Yang, Wei Yuan, Huaisu Dou, Wei Wang, Daguang Zhang, Yuan Bian
Nowadays, biopsy is a decisive method of lung cancer diagnosis, whereas lung biopsy is time-consuming, complex and inaccurate. So a computed tomography-compatible robot for rapid and precise lung biopsy is developed in this article. According to the actual operation process, the robot is divided into two modules: 4-degree-of-freedom position module for location of puncture point is appropriate for patient's almost all positions and 3-degree-of-freedom tendon-based orientation module with remote center of motion is compact and computed tomography-compatible to orientate and insert needle automatically inside computed tomography bore...
February 1, 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28192651/current-rectification-through-vertical-heterojunctions-between-two-single-layer-dichalcogenides-wse2-mos2-pn-junctions
#15
Hrishikesh Bhunia, Abhijit Bera, Amlan J Pal
We form junctions between two single layers of p-type WSe2 and n-type MoS2 in both sequences. The WSe2|MoS2 and MoS2|WSe2 junctions of ultimate thickness limit exhibit current rectification when characterized vertically with a scanning tunneling microscope (STM) tip. The direction of rectification in the pn-junction is opposite to that of the np-junction confirming occurrence of the rectification to be due to the junctions themselves. From scanning tunneling spectroscopy (STS) and correspondingly the density of states (DOS), we locate the conduction and valence band-edges (CB and VB, respectively) of the materials inferring their single-layer and 2H phase configuration...
February 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28187974/no-correlation-between-two-dimensional-measurements-and-three-dimensional-configuration-of-the-pharyngeal-upper-airway-space-in-cone-beam-computed-tomography
#16
Marie Dorothée Abé-Nickler, Samira Pörtner, Peter Sieg, Samer George Hakim
The aim of this study was to evaluate both the 2-dimensional (2D) and 3-dimensional (3D) configuration of the posterior airway space (PAS) in healthy 239 patients using cone-beam computed tomography (CBCT). In particular, we investigated the correlation between the 2D and 3D measurements in view of the potential impact on diagnosis of upper airway obstruction. The pharyngeal airway of each patient was studied at five levels: the level of the posterior nasal spine (PNS), the level of half-height of the PNS and the tip of the soft palate, the level of the tip of the soft palate, the level of the anterior-inferior point of the second vertebra, and at least the level of the top of the epiglottis...
January 10, 2017: Journal of Cranio-maxillo-facial Surgery
https://www.readbyqxmd.com/read/28186194/control-of-finite-critical-behaviour-in-a-small-scale-social-system
#17
Bryan C Daniels, David C Krakauer, Jessica C Flack
Many adaptive systems sit near a tipping or critical point. For systems near a critical point small changes to component behaviour can induce large-scale changes in aggregate structure and function. Criticality can be adaptive when the environment is changing, but entails reduced robustness through sensitivity. This tradeoff can be resolved when criticality can be tuned. We address the control of finite measures of criticality using data on fight sizes from an animal society model system (Macaca nemestrina, n=48)...
February 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28182065/comparative-evaluation-of-canal-cleaning-ability-of-various-rotary-endodontic-filesin-apical-third-a-scanning-electron-microscopic-study
#18
Ganesh Ranganath Jadhav, Priya Mittal, Anish Kulkarni, Shibli Syed, Ravikiran Bagul, Saina Elahi, Dheeraj Kalra
BACKGROUND: The purpose of this study was to evaluate the canal cleaning ability of three novel endodontic rotary instruments and compare with ProTaper files as a control in apical third of root canals under scanning electron microscopy (SEM). MATERIALS AND METHODS: Eighty freshly extracted mandibular premolars were selected according to inclusion criteria. Buccal cusp tips were ground to ensure having a flat coronal reference point with a total tooth length of 16 mm for all samples...
November 2016: Dental Research Journal
https://www.readbyqxmd.com/read/28181615/true-non-contact-atomic-force-microscopy-imaging-of-heterogeneous-biological-samples-in-liquids-topography-and-material-contrast
#19
Lisa Almonte, Jaime Colchero
The present work analyses how the tip-sample interaction signals critically determine the operation of an Atomic Force Microscope (AFM) set-up immersed in liquid. On heterogeneous samples, the conservative tip-sample interaction may vary significantly from point to point - in particular from attractive to repulsive - rendering correct feedback very challenging. Lipid membranes prepared on a mica substrate are analyzed as reference samples which are locally heterogeneous (material contrast). The AFM set-up is operated dynamically at low oscillation amplitude and all available experimental data signals - the normal force, as well as the amplitude and frequency - are recorded simultaneously...
February 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28181582/trapping-phenomenon-attenuates-the-consequences-of-tipping-points-for-limit-cycles
#20
Everton S Medeiros, Iberê L Caldas, Murilo S Baptista, Ulrike Feudel
Nonlinear dynamical systems may be exposed to tipping points, critical thresholds at which small changes in the external inputs or in the system's parameters abruptly shift the system to an alternative state with a contrasting dynamical behavior. While tipping in a fold bifurcation of an equilibrium is well understood, much less is known about tipping of oscillations (limit cycles) though this dynamics are the typical response of many natural systems to a periodic external forcing, like e.g. seasonal forcing in ecology and climate sciences...
February 9, 2017: Scientific Reports
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