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Critical torque

Luke Kaplan, Athena Ierokomos, Praveen Chowdary, Zev Bryant, Bianxiao Cui
Long-distance axonal transport is critical to the maintenance and function of neurons. Robust transport is ensured by the coordinated activities of multiple molecular motors acting in a team. Conventional live-cell imaging techniques used in axonal transport studies detect this activity by visualizing the translational dynamics of a cargo. However, translational measurements are insensitive to torques induced by motor activities. By using gold nanorods and multichannel polarization microscopy, we simultaneously measure the rotational and translational dynamics for thousands of axonally transported endosomes...
March 2018: Science Advances
M Travis Byrd, Brian J Wallace, Jody L Clasey, Haley C Bergstrom
This study examined the contribution of lower body strength and isokinetic peak torque measures to the prediction of critical power (CP) and anaerobic work capacity (AWC). Fourteen recreationally trained males (mean ± SD age: 22.4 ± 2.5 yrs; height: 177.9 ± 7.7 cm; body mass: 84.2 ± 12.4 kg) with anaerobic training experience completed this study. The lower body strength measures included one repetition max (1RM) bilateral back squat [BSq], isokinetic peak torque at 30°·sec [PT30] and isokinetic peak torque at 240°·sec [PT240]) of the dominant leg...
February 27, 2018: Journal of Strength and Conditioning Research
Jan Gimsa
AC fields induce charges at the structural interfaces of particles or biological cells. The interaction of these charges with the field generates frequency-dependent forces that are the basis for AC-electrokinetic effects such as dielectrophoresis (DEP), electrorotation (ROT), and electro-orientation. The effects can be used for the manipulation or dielectric single-particle spectroscopy. The observation of a particular effect depends on the spatial and temporal field distributions, as well as on the shape and the dielectric and viscoelastic properties of the object...
February 21, 2018: Electrophoresis
Susan M Linder, Anson B Rosenfeldt, Andrew S Bazyk, Mandy Miller Koop, Sarah Ozinga, Jay L Alberts
Background Individuals with stroke present with motor control deficits resulting in the abnormal activation and timing of agonist and antagonist muscles and inefficient movement patterns. The analysis of pedaling biomechanics provides a window into understanding motor control deficits, which vary as a function of workload. Understanding the relationship between workload and motor control is critical when considering exercise prescription during stroke rehabilitation. Objectives To characterize pedaling kinematics and motor control processes under conditions in which workload was systematically increased to an eventual patient-specific maximum...
February 15, 2018: Topics in Stroke Rehabilitation
Mengxing Wang, Wenlong Cai, Kaihua Cao, Jiaqi Zhou, Jerzy Wrona, Shouzhong Peng, Huaiwen Yang, Jiaqi Wei, Wang Kang, Youguang Zhang, Jürgen Langer, Berthold Ocker, Albert Fert, Weisheng Zhao
Perpendicular magnetic tunnel junctions based on MgO/CoFeB structures are of particular interest for magnetic random-access memories because of their excellent thermal stability, scaling potential, and power dissipation. However, the major challenge of current-induced switching in the nanopillars with both a large tunnel magnetoresistance ratio and a low junction resistance is still to be met. Here, we report spin transfer torque switching in nano-scale perpendicular magnetic tunnel junctions with a magnetoresistance ratio up to 249% and a resistance area product as low as 7...
February 14, 2018: Nature Communications
Yohei Hamada, Manami Kitamura, Yasuhiro Yamada, Yoshinori Sanada, Takamitsu Sugihara, Saneatsu Saito, Kyaw Moe, Takehiro Hirose
A new method for evaluating the in situ rock strength beneath the seafloor is proposed and applied to the Nankai Trough accretionary prism. The depth-continuous in situ rock strength is a critical parameter for numerous studies in earth science, particularly for seismology and tectonics at plate convergence zones; yet, measurements are limited owing to a lack of drilled cores. Here, we propose a new indicator of strength, the equivalent strength (EST), which is determined only by drilling performance parameters such as drill string rotational torque, bit depth, and string rotational speed...
February 14, 2018: Scientific Reports
Jonathan D Gelber, Lonnie Soloff, Mark S Schickendantz
Overhead athletes subject their shoulders to extreme repetitive torque, compression, distraction, and translation stresses, resulting in adaptive changes of the soft tissues and osseous structures within and around the glenohumeral joint. These anatomic adaptations result in biomechanical enhancements, which improve performance. Understanding the difference between necessary and adaptive changes and pathologic findings is critical when making treatment decisions. Injuries to the shoulder of the overhead athlete can be generally classified into three groups: internal impingement, internal impingement with acquired secondary anterior instability, and primary anterior or multidirectional instability...
March 15, 2018: Journal of the American Academy of Orthopaedic Surgeons
Christopher M McAndrew, Avinesh Agarwalla, Adam C Abraham, Eric Feuchtbaum, William M Ricci, Simon Y Tang
BACKGROUND: Successful fracture fixation depends critically on the stability of the screw-bone interface. Maximum achievable screw torque reflects the competence of this interface, but it cannot be quantified prior to screw stripping. Typically, the surgeon relies on the patients' bone mineral density and radiographs, along with experience and tactile feedback to assess whether sufficient compression can be generated by the screw and bone. However, the local bone quality would also critically influence the strength of the bone-screw interface...
February 2, 2018: Clinical Biomechanics
Takahide Kubota, Yusuke Ina, Zhenchao Wen, Koki Takanashi
Current perpendicular-to-plane (CPP) giant magnetoresistance (GMR) effects are of interest in a possible application of magnetic sensor elements, such as read-head of hard disk drives. To improve the junction performance, the interface tailoring effects were investigated for the Heulser alloy, Co₂Fe0.4Mn0.6Si (CFMS), based CPP-GMR junctions with an L 1 2 -Ag₃Mg ordered alloy spacer. Ultra-thin Fe or Mg inserts were utilized for the CFMS/Ag₃Mg interfaces, and CPP-GMR at low bias current density, J and the J dependence were evaluated for the junctions...
January 31, 2018: Materials
Mehdi Kordi, Campbell Menzies, Len Parker Simpson
PURPOSE: The curvature constant (W') and asymptote (critical power; CP) of the power-duration relationship are important parameters for explaining cycling performance. Short-duration endurance cycling events rely more heavily on the W'; however, the full mechanistic underpinning of this parameter is yet to be determined. Evidence suggests both muscle volume and muscle strength may contribute to the magnitude of W'. Therefore, the present study investigated the relationship between power-duration parameters (CP and W') and (1) anthropometric and (2) mechanical properties of thigh muscles in a sample of elite cyclists...
March 2018: European Journal of Applied Physiology
Paul T Morgan, Joanna L Bowtell, Anni Vanhatalo, Andrew M Jones, Stephen J Bailey
AIM: Acetaminophen is a commonly used medicine for pain relief and emerging evidence suggests that it may improve endurance exercise performance. This study investigated some of the physiological mechanisms by which acute acetaminophen ingestion might blunt muscle fatigue development. METHODS: Thirteen active males completed 60 × 3 s maximum voluntary contractions (MVC) of the knee extensors with each contraction separated by a 2 s passive recovery period...
January 13, 2018: European Journal of Applied Physiology
Keitaro Matsukawa, Yuichiro Abe, Yoshihide Yanai, Yoshiyuki Yato
BACKGROUND: The sufficiency of screw anchoring is a critical factor for achieving successful spinal fusion; however, no reliable method for predicting pedicle screw fixation has been established. Recently, Hounsfield units (HU) obtained from computed tomography (CT) was developed as a new reliable tool to determine the bone quality. The purpose of the present study was to demonstrate the utility of regional HU measurement of the screw trajectory to predict the primary and long-term fixation strength of pedicle screws...
February 2018: Acta Neurochirurgica
W Grymonpré, G Verstraete, V Vanhoorne, J P Remon, T De Beer, C Vervaet
The concept of twin-screw melt granulation (TSMG) has steadily (re)-gained interest in pharmaceutical formulation development as an intermediate step during tablet manufacturing. However, to be considered as a viable processing option for solid oral dosage forms there is a need to understand all critical sources of variability which could affect this granulation technique. The purpose of this study was to provide an in-depth analysis of the continuous TSMG process in order to expose the critical process parameters (CPP) and elucidate the impact of process and formulation parameters on the critical quality attributes (CQA) of granules and tablets during continuous TSMG...
December 14, 2017: European Journal of Pharmaceutics and Biopharmaceutics
J Matt McCrary, Bronwen J Ackermann, Mark Halaki
OBJECTIVES: Electromyographic (EMG) fatigue threshold (EMGFT ) is utilised as a correlate of critical power, torque, and force thresholds that establishes a theoretical exercise intensity-the power, torque, or force at which the rate of change of EMG amplitude (ΔEM¯G) is zero-below which neuromuscular fatigue is negligible and unpredictable. Recent studies demonstrating neuromuscular fatigue below critical thresholds raise questions about the construct validity of EMGFT . The purpose of this analysis is to evaluate the construct validity of EMGFT by aggregating ΔEM¯G and time to task failure (Tlim ) data...
November 11, 2017: Journal of Science and Medicine in Sport
Chang-Woo Cho, Jonathan Haiwei Yang, Noah F Q Yuan, Junying Shen, Thomas Wolf, Rolf Lortz
We investigate the magnetic phase diagram near the upper critical field of KFe_{2}As_{2} by magnetic torque and specific heat experiments using a high-resolution piezorotary positioner to precisely control the parallel alignment of the magnetic field with respect to the FeAs layers. We observe a clear double transition when the field is strictly aligned in the plane and a characteristic upturn of the upper critical field line, which goes far beyond the Pauli limit at 4.8 T. This provides firm evidence that a Fulde-Ferrell-Larkin-Ovchinnikov state exists in this iron-based KFe_{2}As_{2} superconductor...
November 24, 2017: Physical Review Letters
Danny Vogel, Andreas Rathay, Stephanie Teufel, Martin Ellenrieder, Carmen Zietz, Manuela Sander, Rainer Bader
PURPOSE: In THA a sufficient primary implant stability is the precondition for successful secondary stability. Industrial foams of different densities have been used for primary stability investigations. The aim of this study was to analyse and compare the insertion behaviour of threaded and press-fit cups in vivo and ex vivo using bone substitutes with various densities. METHODS: Two threaded (Bicon Plus®, Trident® TC) and one press-fit cup (Trident PSL®) were inserted by orthopaedic surgeons (S1, S2) into 10, 20 and 31 pcf blocks, using modified surgical instruments allowing measurements of the insertion forces and torques...
2017: Acta of Bioengineering and Biomechanics
Sebastian Altmeyer, Younghae Do, Soorok Ryu
We investigate transient behaviors induced by magnetic fields on the dynamics of the flow of a ferrofluid in the gap between two concentric, independently rotating cylinders. Without applying any magnetic fields, we uncover emergence of flow states constituted by a combination of a localized spiral state in the top and bottom of the annulus and different multi-cell flow states with toroidally closed vortices in the interior of the bulk. However, when a magnetic field is presented, we observe the transient behaviors between multi-cell states passing through two critical thresholds in a strength of an axial (transverse) magnetic field...
November 2017: Chaos
Sam Davila, E Scott Halstead, Mark W Hall, Allan Doctor, Russell Telford, Richard Holubkov, Joseph A Carcillo, Gregory A Storch
OBJECTIVES: Demonstrate that DNA viremia is common in pediatric sepsis and quantitate its associations with host immune function and secondary infection risk. DESIGN: Retrospective analysis of a prospective cohort study. PATIENTS: Seventy-three children admitted with sepsis-induced organ failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: This study was performed as an ancillary investigation to a single-center prospective study of children with severe sepsis...
January 2018: Pediatric Critical Care Medicine
Ian J Dempsey, Grant E Norte, Matthew Hall, John Goetschius, Lindsay V Slater, Jourdan M Cancienne, Brian C Werner, David R Diduch, Joseph M Hart
CONTEXT: Post-operative rehabilitation is critical to optimize outcomes after anterior cruciate ligament reconstruction (ACLR). However, the relationship between physical therapy (PT) and clinical outcomes is unclear. OBJECTIVE: To describe PT characteristics following ACLR, and assess the relationships between PT characteristics, surgical procedure, and clinical outcomes. DESIGN: Cross-sectional. SETTING: Laboratory...
November 15, 2017: Journal of Sport Rehabilitation
Chenchen Jiang, Haojian Lu, Ke Cao, Wenfeng Wan, Yajing Shen, Yang Lu
Microwires, such as metallic, semiconductor, and polymer microwires and carbon fibers, have stimulated great interest due to their importance in various structural and functional applications. Particularly, metallic glass (MG) microwires, because of their amorphous atoms arrangement, have some unique mechanical properties compared with traditional metals. Despite the fact that substantial research efforts have been made on the mechanical characterizations of metallic glass microwires under tension or flexural bending, the mechanical properties of microwires under torsional loading have not been well studied, mainly due to the experimental difficulties, such as the detection of torsion angle, quantitative measurement of the torsional load, and the alignment between the specimen and torque meter...
2017: Scanning
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