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https://www.readbyqxmd.com/read/28632407/prediction-of-the-structural-response-of-the-femoral-shaft-under-dynamic-loading-using-subject-specific-finite-element-models
#1
Gwansik Park, Taewung Kim, Jason Forman, Matthew B Panzer, Jeff R Crandall
The goal of this study was to predict the structural response of the femoral shaft under dynamic loading conditions using subject-specific finite element (SS-FE) models and to evaluate the prediction accuracy of the models in relation to the model complexity. In total, SS-FE models of 31 femur specimens were developed. Using those models, dynamic three-point bending and combined loading tests (bending with four different levels of axial compression) of bare femurs were simulated, and the prediction capabilities of five different levels of model complexity were evaluated based on the impact force time histories: baseline, mass-based scaled, structure-based scaled, geometric SS-FE, and heterogenized SS-FE models...
June 20, 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/28618334/comprehensive-modelling-and-simulation-of-cylindrical-nanoparticles-manipulation-by-using-a-virtual-reality-environment
#2
Moharam Habibnejad Korayem, Ali Kafash Hoshiar, Maedeh Ghofrani
With the expansion of nanotechnology, robots based on atomic force microscope (AFM) have been widely used as effective tools for displacing nanoparticles and constructing nanostructures. One of the most limiting factors in AFM-based manipulation procedures is the inability of simultaneously observing the controlled pushing and displacing of nanoparticles while performing the operation. To deal with this limitation, a virtual reality environment has been used in this paper for observing the manipulation operation...
June 8, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28579576/automated-ablation-annotation-algorithm-reduces-re-conduction-of-isolated-pulmonary-vein-and-improves-outcome-after-catheter-ablation-for-atrial-fibrillation
#3
Nobuaki Tanaka, Koichi Inoue, Koji Tanaka, Yuko Toyoshima, Takafumi Oka, Masato Okada, Hiroyuki Inoue, Ryo Nakamaru, Yasushi Koyama, Atsunori Okamura, Katsuomi Iwakura, Yasushi Sakata, Kenshi Fujii
BACKGROUND: Durable pulmonary vein isolation (PVI) is critical in reducing recurrence after radiofrequency catheter ablation for atrial fibrillation (AF). The VISITAG Module, an automatic annotation system that takes account of catheter stability and contact force (CF), might be useful in accomplishing this.Methods and Results:In 49 patients undergoing VISITAG-guided AF ablation (group A), we set the following automatic annotation criteria: catheter stability range of motion ≤1...
June 2, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28538316/load-absorption-force-time-characteristics-following-the-second-pull-of-weightlifting-derivatives
#4
Timothy J Suchomel, Jason P Lake, Paul Comfort
Suchomel, TJ, Lake, JP, and Comfort, P. Load absorption force-time characteristics following the second pull of weightlifting derivatives. J Strength Cond Res 31(6): 1644-1652, 2017-The purpose of this study was to compare the load absorption force-time characteristics of weightlifting catching and pulling derivatives. Twelve resistance-trained men performed repetitions of the hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) on a force platform with 30, 45, 65, and 80% of their 1-repetition maximum HPC...
June 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28532279/the-effect-of-cold-ambient-temperatures-on-climbing-specific-finger-flexor-performance
#5
Kevin Phillips, Byungjoo Noh, Matthew Gage, Tejin Yoon
Different ambient temperatures are known to affect muscular performance based on the type of contraction. The effect of cold (10°C) and thermoneutral (TN) (24°C) ambient temperatures on finger flexor performance was examined in 12 rock climbers. After 30 min of seated rest in the designated temperature condition, participants completed maximal voluntary contractions (MVC) on a climbing-specific finger flexor assessment device equipped with a crimp grip hold. Participants then completed an intermittent fatiguing task until failure...
August 2017: European Journal of Sport Science
https://www.readbyqxmd.com/read/28515113/force-sensing-catheters-during-pediatric-radiofrequency-ablation-the-federation-study
#6
Aarti S Dalal, Hoang H Nguyen, Tammy Bowman, George F Van Hare, Jennifer N Avari Silva
BACKGROUND: Based on data from studies of atrial fibrillation ablations, optimal parameters for the TactiCath (TC; St. Jude Medical, Inc) force-sensing ablation catheter are a contact force of 20 g and a force-time integral of 400 g·s for the creation of transmural lesions. We aimed to evaluate TC in pediatric and congenital heart disease patients undergoing ablation. METHODS AND RESULTS: Comprehensive chart and case reviews were performed from June 2015 to March 2016...
May 17, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28469741/biomechanical-differences-in-the-sprint-start-between-faster-and-slower-high-level-sprinters
#7
Milan Čoh, Stanislav Peharec, Petar Bačić, Krzyszfof Mackala
The purpose of this study was to examine the kinematic and kinetic differences of the sprint start and first two steps between faster and slower high-level sprinters. Twelve male sprinters were dichotomized according to personal best 60- and 100-m times. Each participant performed five starts under constant conditions. An eight-camera system was used for 3-D kinematic analysis. Dynamic forces at the start were determined with starting blocks mounted on bipedal force plates. Measures of front and rear block total force, front and rear block maximal force, time to front and rear block peak force, total force impulse, total horizontal and vertical impulse, front and rear block force impulse, time of block clearance, block leaving velocity and block leaving acceleration were collected...
February 2017: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28432503/high-voltage-zones-within-the-pulmonary-vein-antra-major-determinants-of-acute-pulmonary-vein-reconnections-after-atrial-fibrillation-ablation
#8
Koichi Nagashima, Ichiro Watanabe, Yasuo Okumura, Kazuki Iso, Keiko Takahashi, Ryuta Watanabe, Masaru Arai, Sayaka Kurokawa, Toshiko Nakai, Kimie Ohkubo, Shunichi Yoda, Atsushi Hirayama
PURPOSE: Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is mainly due to PV reconnections. Patient-specific tissue characteristics that may contribute remain unidentified. This study aimed to assess the relationship between the bipolar electrogram voltage amplitudes recorded from the PV-left atrial (LA) junction and acute PV reconnection sites. METHODS: Three-dimensional LA voltage maps created before an extensive encircling PVI in 47 AF patients (31 men; mean age 62 ± 11 years) were examined for an association between the EGM voltage amplitude recorded from the PV-LA junction and acute post-PVI PV reconnections (spontaneous PV reconnections and/or ATP-provoked dormant PV conduction)...
April 21, 2017: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/28426514/comparison-of-the-hang-high-pull-and-loaded-jump-squat-for-the-development-of-vertical-jump-and-isometric-force-time-characteristics
#9
Dustin J Oranchuk, Tracey L Robinson, Zachary J Switaj, Eric J Drinkwater
Weightlifting movements have high skill demands and require expert coaching. Loaded jumps have a comparably lower skill demand, but may be similarly effective for improving explosive performance. The purpose of this study was to compare vertical jump performance, isometric force, and rate of force development (RFD) following a ten-week intervention employing the hang high-pull (hang-pull) or trap-bar jump squat (jump-squat). Eighteen NCAA Division II swimmers (8 males, 10 females) with at least one year of resistance training experience volunteered to participate...
April 15, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28419605/radiofrequency-catheter-ablation-of-atrial-fibrillation-electrical-modification-suggesting-transmurality-is-faster-achieved-with-remote-magnetic-catheter-in-comparison-with-contact-force-use
#10
Sok-Sithikun Bun, Anis Ayari, Decebal Gabriel Latcu, Abdelkarim Errahmouni, Nadir Saoudi
BACKGROUND: Remote magnetic navigation (RMN) and contact force (CF) sensing catheters are available technologies for radiofrequency (RF) catheter ablation of atrial fibrillation (AF). Our purpose was to compare time to electrogram (EGM) modification suggesting transmural lesions between RMN and CF-guided AF ablation. METHODS AND RESULTS: A total of 1,008 RF applications were analyzed in 21 patients undergoing RMN (n = 11) or CF-guided ablation (n = 10) for paroxysmal AF...
April 17, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28415068/validity-and-reliability-of-a-portable-isometric-mid-thigh-clean-pull
#11
Lachlan P James, Llion A Roberts, G Gregory Haff, Vincent G Kelly, Emma M Beckman
James, LP, Roberts, LA, Haff, GG, Kelly, VG, and Beckman, EM. Validity and reliability of a portable isometric mid-thigh clean pull. J Strength Cond Res 31(5): 1378-1386, 2017-This study investigated the test-retest reliability and criterion validity of force-time curve variables collected through a portable isometric mid-thigh clean pull (IMTP) device equipped with a single-axial load cell. Fifteen males with ≥6 months of resistance training experience attended two testing sessions. In each session, participants performed an IMTP in 2 separate conditions in a randomized counterbalanced manner...
May 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28381417/determinants-of-acute-and-late-pulmonary-vein-reconnection-in-contact-force-guided-pulmonary-vein-isolation-identifying-the-weakest-link-in-the-ablation-chain
#12
COMPARATIVE STUDY
Milad El Haddad, Philippe Taghji, Thomas Phlips, Michael Wolf, Anthony Demolder, Rajin Choudhury, Sébastien Knecht, Yves Vandekerckhove, Rene Tavernier, Hiroshi Nakagawa, Mattias Duytschaever
BACKGROUND: Pulmonary vein reconnection (PVR) still determines recurrences of atrial fibrillation after contact force (CF)-guided pulmonary vein isolation. We studied whether acute PVR (adenosine and waiting time) and late PVR (at repeat) are explained by incomplete transmurality and contiguity within the deployed radiofrequency circle. METHODS AND RESULTS: We analyzed 42 CF-guided ipsilateral pulmonary vein isolation procedures. For each radiofrequency tag within the circle, we collected data reflecting lesion depth (time of application, power, impedance drop [Δ-Imp], CF, force-time integral [FTI], and ablation index [AI]) and contiguity (automated interlesion distance [ILD])...
April 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28344070/unintentional-force-changes-in-cyclical-tasks-performed-by-an-abundant-system-empirical-observations-and-a-dynamical-model
#13
Sasha Reschechtko, Fariba Hasanbarani, Vladimir M Akulin, Mark L Latash
The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1Hz, paced by an auditory metronome. One - Force task - required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task - Share task - required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed...
March 24, 2017: Neuroscience
https://www.readbyqxmd.com/read/28339367/the-functional-significance-of-morphological-changes-in-the-dentitions-of-early-mammals
#14
Andrew J Conith, Michael J Imburgia, Alfred J Crosby, Elizabeth R Dumont
The Mesozoic marked a time of experimentation in the tooth morphology of early mammals. One particular experiment involved the movement of three points, or cusps, on the surface of a molar tooth from a line into a triangle. This transition is exemplified by two extinct insectivorous mammals, Morganucodon (cusps in a line) and Kuehneotherium (cusps in a triangle). Here we test whether this difference in cusp arrangement, alongside cusp heights and angles between cusps, is associated with differences in the ability of the teeth to fracture proxy-insect prey...
November 2016: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28282758/the-effects-of-barbell-load-on-countermovement-vertical-jump-power-and-net-impulse
#15
Peter D Mundy, Neal A Smith, Mike A Lauder, Jason P Lake
The aim of this study was to examine the effects of barbell load on countermovement vertical jump (CMJ) power and net impulse within a theoretically valid framework, cognisant of the underpinning force, temporal, and spatial components. A total of 24 resistance-trained rugby union athletes (average ± SD: age: 23.1 ± 3.4 years; height: 1.83 ± 0.05 m; body mass (BM): 91.3 ± 10.5 kg) performed maximal CMJ under 5 experimental conditions in a randomised, counterbalanced order: unloaded, and with additional loads of 25%, 50%, 75%, and 100% of BM...
September 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28276490/magnetically-controlled-ferromagnetic-swimmers
#16
Joshua K Hamilton, Peter G Petrov, C Peter Winlove, Andrew D Gilbert, Matthew T Bryan, Feodor Y Ogrin
Microscopic swimming devices hold promise for radically new applications in lab-on-a-chip and microfluidic technology, diagnostics and drug delivery etc. In this paper, we demonstrate the experimental verification of a new class of autonomous ferromagnetic swimming devices, actuated and controlled solely by an oscillating magnetic field. These devices are based on a pair of interacting ferromagnetic particles of different size and different anisotropic properties joined by an elastic link and actuated by an external time-dependent magnetic field...
March 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28260190/general-anesthesia-improves-contact-force-and-reduces-gap-formation-in-pulmonary-vein-isolation-a-comparison-with-conscious-sedation
#17
Akio Chikata, Takeshi Kato, Takanori Yaegashi, Satoru Sakagami, Chieko Kato, Takahiro Saeki, Keiichi Kawai, Shin-Ichiro Takashima, Hisayoshi Murai, Soichiro Usui, Hiroshi Furusho, Shuichi Kaneko, Masayuki Takamura
Compared to conscious sedation (CS), the use of general anesthesia (GA) in pulmonary vein isolation (PVI) is associated with a lower recurrence rate of atrial fibrillation (AF). GA may improve catheter stability and mapping system accuracy compared to CS, but its influence on contact force (CF) parameters during ipsilateral PVI has not previously been investigated. The study population comprised 176 consecutive patients (107 in GA group and 69 in CS group) with AF who underwent their first PVI procedure. We retrospectively assessed CF parameters, force-time integral (FTI), FTI/wall thickness during anatomical ipsilateral PVI and long-term outcome after ablation...
March 4, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28254291/bio-inspired-enhancement-of-friction-and-adhesion-at-the-polydimethylsiloxane-intestine-interface-and-biocompatibility-characterization
#18
Hongyu Zhang, Yi Wang, Steven Vasilescu, Zhibin Gu, Tao Sun
An active navigation of self-propelled miniaturized robot along the intestinal tract without injuring the soft tissue remains a challenge as yet. Particularly in this case an effective control of the interfacial friction and adhesion between the material used and the soft tissue is crucial. In the present study, we investigated the frictional and adhesive properties between polydimethylsiloxane (PDMS, microscopically patterned with micro-pillar arrays and non-patterned with a flat surface) and rabbit small intestinal tract using a universal material tester...
May 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28242568/the-mechanism-of-force-transference-in-feet-of-children-ages-two-to-six
#19
Mingyu Hu, Nan Zhou, Bo Xu, Wuyong Chen, Jianxin Wu, Jin Zhou
The aim of this study was to design an algorithm to quantify the plantar force transference of children from ages 2-6. In total, 319 healthy children without abnormal gait patterns, foot deformities or injuries, able to walk independently, and with normal BMIs were recruited, and their plantar force distributions were measured. Their plantar areas were divided into ten parts: the hallux, toes #2-5, the first to fifth metatarsal heads (1st-5th MTH), the mid-foot (MF), medial heel (MH) and lateral heel (LH), in which a relative force-time integral (FTIrel) (%) was calculated...
February 22, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28208410/local-equilibria-and-state-transfer-of-charged-classical-particles-on-a-helix-in-an-electric-field
#20
J Plettenberg, J Stockhofe, A V Zampetaki, P Schmelcher
We explore the effects of a homogeneous external electric field on the static properties and dynamical behavior of two charged particles confined to a helix. In contrast to the field-free setup which provides a separation of the center-of-mass and relative motion, the existence of an external force perpendicular to the helix axis couples the center-of-mass to the relative degree of freedom leading to equilibria with a localized center of mass. By tuning the external field various fixed points are created and/or annihilated through different bifurcation scenarios...
January 2017: Physical Review. E
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