Abstract Muscles are the actuators that drive human movement. However, despite many decades of work, we still cannot readily assess forces muscles transmit during Direct measurements muscle–tendon loads invasive and modeling approaches require assumptions. Here, introduce a non-invasive approach to tendon by tracking vibrational behavior. We first show speed shear wave propagation in increases with square root axial stress. then remarkably simple tensiometer uses micron-scale taps...

The dynamics of any mechanical system can be described in terms forces and motions. interaction these is often captured the metric impedance - a generalization stiffness used to describe how resists application force. ability adaptively change advantageous when encountering variable environmental conditions. Changing robotic systems limited, whereas humans rapidly elegantly adapt their limbs, especially during initial contact with objects. This true for movements our arms hands. Multiple...

The control of kinematically redundant robots is often approached using nullspace projection, which requires precise models and can be computationally challenging.Humans have many more degrees freedom than are required to accomplish their tasks, but given neuro-mechanical limitations, it seems unlikely that biology relies on or complex computation.An alternative biologically-inspired approach leverages the compositionality mechanical impedance.In theory, projection eliminates any conflict...

Physically interacting with kinematic constraints is commonplace in everyday actions. We report a study of humans turning crank, circular constraint that imposes constant hand path curvature and hence should suppress variations speed due to the power-law speed-curvature relation widely reported for unconstrained motions. Remarkably, we found that, when peripheral biomechanical factors are removed, reemerges, indicating it is, at least part, neural origin.

The multi-leaf collimator (MLC) assembly present on TomoTherapy (Accuray, Madison WI) radiation therapy (RT) and mega voltage CT machines is well suited to perform fluence field modulated (FFMCT). In addition, there a demand in the RT environment for FFMCT imaging techniques, specifically volume of interest (VOI) imaging. A clinical machine was programmed VOI. Four different size ROIs were placed at varying distances from isocenter. Projections intersecting VOI received 'full dose' while...

Fluence field modulated CT allows for improvements in image quality and dose reduction. To date, only 1-D modulators have been proposed, the extension to 2-D modulation is difficult with solid-metal attenuation-based modulators. This work proposes use liquids gas attenuate x-ray beam which can be arrayed allowing fluence modulation. The thickness of liquid pressure a given path length were determined that provided same attenuation as 30 cm soft tissue at 80, 100, 120, 140 kV. Gaseous Xenon...

Fluence field modulated (FFM) CT allows for improvements in image quality and dose reduction. To date, only one-dimensional modulators have been proposed, as the extension to two-dimensional (2-D) modulation is difficult with solid-metal attenuation-based fluence designs. This work proposes use liquid gas attenuate x-ray beam, unlike solids, these materials can be arranged allowing 2-D modulation. The thickness of pressure a given path length were determined that provided same attenuation 30...

Humans excel at physical interaction despite long feedback delays and low-bandwidth actuators. Yet little is known about how humans manage interaction. A quantitative understanding of they do critical for designing machines that can safely effectively interact with humans, e.g. amputation prostheses, assistive exoskeletons, therapeutic rehabilitation robots, human-robot collaboration. To facilitate applications, this should be in the form a simple mathematical model not only describes...

Humans substantially outperform robotic systems in tasks that require physical interaction, despite seemingly inferior muscle bandwidth and slow neural information transmission. The control strategies enable this performance remain poorly understood. To bridge gap, study examined kinematically constrained motion as an intermediate step between the widely studied unconstrained motions sparsely interactions. Subjects turned a horizontal planar crank two directions (clockwise counterclockwise)...

When performing Computed Tomographic (CT) image reconstruction on digital subtraction angiography (DSA) projections, loss of vessel contrast has been observed behind highly attenuating anatomy, such as dental implants and large filled aneurysms. Because this typically occurs only in a limited range projection angles, the time course can potentially be altered. In work, we have developed model for acquiring DSA projections that models both polychromatic nature x-ray spectrum scattering...

Ten right-handed male subjects turned a crank (radius 10.29 cm) in two directions at three constant instructed speeds (fast, medium, very slow) with visual speed feedback. They completed 23 trials each speed. With the hand constrained to move circle, non-zero forces against constraint were measured. Assuming plausible mathematical model of interactive dynamics, peripheral neuromechanics could be `subtracted', revealing an underlying motion that reflected neural control. We called this...

Purpose: Fluence field modulated CT (FFMCT) and volume of interest (VOI) imaging applications require adjustment the profile x‐ray fluence incident on a patient as function view angle. Since current FFMCT prototypes can theoretically take an infinite number configurations, measuring calibration data set for all possible positions would not be feasible. The present work details methodology calculating atlas configurations that will span likely body regions, sizes, positioning, modes....

Abstract The motor neuroscience literature suggests that the central nervous system may encode some commands in terms of velocity. In this work, we tackle question: what consequences would velocity produce at behavioral level? Considering ubiquitous presence noise neuromusculoskeletal system, predict affected by stationary “random walks”, also known as Brownian processes, position. motions are distinctively characterized a linearly growing variance and power spectral density declines inverse...

Purpose: The multi-leaf collimator (MLC) assembly present on TomoTherapy (Accuray, Madison WI) radiation therapy (RT) and mega voltage CT machines is well suited to perform fluence field modulated (FFMCT). In addition, there a demand in the RT environment for FFMCT imaging techniques, specifically volume of interest (VOI) imaging. Methods: A clinical machine was programmed deliver 30% dose outside predefined VOIs. Four different size ROIs were placed at varying distances from isocenter....

Purpose: This work presents a new approach that uses the multi leaf collimator present on TomoTherapy devices to modulate imaging beam. allows for targeted in which only regions of clinical importance IGRT (patient positioning confirmation) receive high level image quality. total dose decrease, especially healthy tissue. Methods: A machine was programmed deliver such small pre‐defined volumes interest (VOI) received relatively higher levels quality with respect surrounding regions. Four...

Falls and fall-related fractures are common in the elderly lead to negative health outcomes. Muscle function balance impairment important risk factors for falls. Traditional exercise improves muscle mass as well balance. However, older adults often do not regularly because of physical cognitive limitations or lack adherence. Whole body vibration promises be an intervention that can overcome some traditional exercise. Yet ensure safety, head brain must protected from high amplitudes...

In Computed Tomographic (CT) image reconstruction for 4 dimensional digital subtraction angiography (4D-DSA), loss of vessel contrast has been observed behind highly attenuating anatomy, such as large filled aneurysms. Although this typically occurs only in a limited range projection angles, the time course can be altered. work we propose an algorithm to correct anatomy within fill data, i.e. The uses 3D-SA volume create correction that is multiplied by 4D-DSA order signal dropout volume....

Abstract The motor neuroscience literature suggests that the central nervous system may encode some commands in terms of velocity. In this work, we tackle question: what consequences would velocity produce at behavioral level? Considering ubiquitous presence noise neuromusculoskeletal system, predict affected by stationary “random walks”, also known as Brownian processes, position. motions are distinctively characterized a linearly growing variance and power spectral density declines inverse...

Abstract The motor neuroscience literature suggests that the central nervous system may encode some commands in terms of velocity. In this work, we tackle question: what consequences would velocity produce at behavioral level? Considering ubiquitous presence noise neuromusculoskeletal system, predict affected by stationary “random walks”, also known as Brownian processes, position. motions are distinctively characterized a linearly growing variance and power spectral density declines inverse...