Structure-function relationship of skeletal muscle provides inspiration for design of new artificial muscle

NASA Astrophysics Data System (ADS)

Gao, Yingxin; Zhang, Chi

2015-03-01

A variety of actuator technologies have been developed to mimic biological skeletal muscle that generates force in a controlled manner. Force generation process of skeletal muscle involves complicated biophysical and biochemical mechanisms; therefore, it is impossible to replace biological muscle. In biological skeletal muscle tissue, the force generation of a muscle depends not only on the force generation capacity of the muscle fiber, but also on many other important factors, including muscle fiber type, motor unit recruitment, architecture, structure and morphology of skeletal muscle, all of which have significant impact on the force generation of the whole muscle or force transmission from muscle fibers to the tendon. Such factors have often been overlooked, but can be incorporated in artificial muscle design, especially with the discovery of new smart materials and the development of innovative fabrication and manufacturing technologies. A better understanding of the physiology and structure-function relationship of skeletal muscle will therefore benefit the artificial muscle design. In this paper, factors that affect muscle force generation are reviewed. Mathematical models used to model the structure-function relationship of skeletal muscle are reviewed and discussed. We hope the review will provide inspiration for the design of a new generation of artificial muscle by incorporating the structure-function relationship of skeletal muscle into the design of artificial muscle.

Development of a linear induction motor based artificial muscle system.

PubMed

Gruber, A; Arguello, E; Silva, R

2013-01-01

We present the design of a linear induction motor based on electromagnetic interactions. The engine is capable of producing a linear movement from electricity. The design consists of stators arranged in parallel, which produce a magnetic field sufficient to displace a plunger along its axial axis. Furthermore, the winding has a shell and cap of ferromagnetic material that amplifies the magnetic field. This produces a force along the length of the motor that is similar to that of skeletal muscle. In principle, the objective is to use the engine in the development of an artificial muscle system for prosthetic applications, but it could have multiple applications, not only in the medical field, but in other industries.

Three-dimensional hysteresis compensation enhances accuracy of robotic artificial muscles

NASA Astrophysics Data System (ADS)

Zhang, Jun; Simeonov, Anthony; Yip, Michael C.

2018-03-01

Robotic artificial muscles are compliant and can generate straight contractions. They are increasingly popular as driving mechanisms for robotic systems. However, their strain and tension force often vary simultaneously under varying loads and inputs, resulting in three-dimensional hysteretic relationships. The three-dimensional hysteresis in robotic artificial muscles poses difficulties in estimating how they work and how to make them perform designed motions. This study proposes an approach to driving robotic artificial muscles to generate designed motions and forces by modeling and compensating for their three-dimensional hysteresis. The proposed scheme captures the nonlinearity by embedding two hysteresis models. The effectiveness of the model is confirmed by testing three popular robotic artificial muscles. Inverting the proposed model allows us to compensate for the hysteresis among temperature surrogate, contraction length, and tension force of a shape memory alloy (SMA) actuator. Feedforward control of an SMA-actuated robotic bicep is demonstrated. This study can be generalized to other robotic artificial muscles, thus enabling muscle-powered machines to generate desired motions.

Artificial Walking Technologies to Improve Gait in Cerebral Palsy: Multichannel Neuromuscular Stimulation.

PubMed

Rose, Jessica; Cahill-Rowley, Katelyn; Butler, Erin E

2017-11-01

Cerebral palsy (CP) is the most common childhood motor disability and often results in debilitating walking abnormalities, such as flexed-knee and stiff-knee gait. Current medical and surgical treatments are only partially effective in improving gait abnormalities and may cause significant muscle weakness. However, emerging artificial walking technologies, such as step-initiated, multichannel neuromuscular electrical stimulation (NMES), can substantially improve gait patterns and promote muscle strength in children with spastic CP. NMES may also be applied to specific lumbar-sacral sensory roots to reduce spasticity. Development of tablet computer-based multichannel NMES can leverage lightweight, wearable wireless stimulators, advanced control design, and surface electrodes to activate lower-limb muscles. Musculoskeletal models have been used to characterize muscle contributions to unimpaired gait and identify high muscle demands, which can help guide multichannel NMES-assisted gait protocols. In addition, patient-specific NMES-assisted gait protocols based on 3D gait analysis can facilitate the appropriate activation of lower-limb muscles to achieve a more functional gait: stance-phase hip and knee extension and swing-phase sequence of hip and knee flexion followed by rapid knee extension. NMES-assisted gait treatment can be conducted as either clinic-based or home-based programs. Rigorous testing of multichannel NMES-assisted gait training protocols will determine optimal treatment dosage for future clinical trials. Evidence-based outcome evaluation using 3D kinematics or temporal-spatial gait parameters will help determine immediate neuroprosthetic effects and longer term neurotherapeutic effects of step-initiated, multichannel NMES-assisted gait in children with spastic CP. Multichannel NMES is a promising assistive technology to help children with spastic CP achieve a more upright, functional gait. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Artificial Muscles Based on Electroactive Polymers as an Enabling Tool in Biomimetics

NASA Technical Reports Server (NTRS)

Bar-Cohen, Y.

2007-01-01

Evolution has resolved many of nature's challenges leading to working and lasting solutions that employ principles of physics, chemistry, mechanical engineering, materials science, and many other fields of science and engineering. Nature's inventions have always inspired human achievements leading to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems, and many other benefits. Some of the technologies that have emerged include artificial intelligence, artificial vision, and artificial muscles, where the latter is the moniker for electroactive polymers (EAPs). To take advantage of these materials and make them practical actuators, efforts are made worldwide to develop capabilities that are critical to the field infrastructure. Researchers are developing analytical model and comprehensive understanding of EAP materials response mechanism as well as effective processing and characterization techniques. The field is still in its emerging state and robust materials are still not readily available; however, in recent years, significant progress has been made and commercial products have already started to appear. In the current paper, the state-of-the-art and challenges to artificial muscles as well as their potential application to biomimetic mechanisms and devices are described and discussed.

A biologically inspired artificial muscle based on fiber-reinforced and electropneumatic dielectric elastomers

NASA Astrophysics Data System (ADS)

Liu, Lei; Zhang, Chi; Luo, Meng; Chen, Xi; Li, Dichen; Chen, Hualing

2017-08-01

Dielectric elastomers (DEs) have great potential for use as artificial muscles because of the following characteristics: electrical activity, fast and large deformation under stimuli, and softness as natural muscles. Inspired by the traditional McKibben actuators, in this study, we developed a cylindrical soft fiber-reinforced and electropneumatic DE artificial muscle (DEAM) by mimicking the spindle shape of natural muscles. Based on continuum mechanics and variation principle, the inhomogeneous actuation of DEAMs was theoretically modeled and calculated. Prototypes of DEAMs were prepared to validate the design concept and theoretical model. The theoretical predictions are consistent with the experimental results; they successfully predicted the evolutions of the contours of DEAMs with voltage. A pneumatically supported high prestretch in the hoop direction was achieved by our DEAM prototype without buckling the soft fibers sandwiched by the DE films. Besides, a continuously tunable prestretch in the actuation direction was achieved by varying the supporting pressure. Using the theoretical model, the failure modes, maximum actuations, and critical voltages were analyzed; they were highly dependent on the structural parameters, i.e., the cylinder aspect ratio, prestretch level, and supporting pressure. The effects of structural parameters and supporting pressure on the actuation performance were also investigated to optimize the DEAMs.

Design and motion control of bioinspired humanoid robot head from servo motors toward artificial muscles

NASA Astrophysics Data System (ADS)

Almubarak, Yara; Tadesse, Yonas

2017-04-01

The potential applications of humanoid robots in social environments, motivates researchers to design, and control biomimetic humanoid robots. Generally, people are more interested to interact with robots that have similar attributes and movements to humans. The head is one of most important part of any social robot. Currently, most humanoid heads use electrical motors, pneumatic actuators, and shape memory alloy (SMA) actuators for actuation. Electrical and pneumatic actuators take most of the space and would cause unsmooth motions. SMAs are expensive to use in humanoids. Recently, in many robotic projects, Twisted and Coiled Polymer (TCP) artificial muscles are used as linear actuators which take up little space compared to the motors. In this paper, we will demonstrate the designing process and motion control of a robotic head with TCP muscles. Servo motors and artificial muscles are used for actuating the head motion, which have been controlled by a cost efficient ARM Cortex-M7 based development board. A complete comparison between the two actuators is presented.

The use of artificial neural networks to predict the muscle behavior

NASA Astrophysics Data System (ADS)

Kutilek, Patrik; Viteckova, Slavka; Svoboda, Zdenĕk; Smrcka, Pavel

2013-09-01

The aim of this article is to introduce methods of prediction of muscle behavior of the lower extremities based on artificial neural networks, which can be used for medical purposes. Our work focuses on predicting muscletendon forces and moments during human gait with the use of angle-time diagram. A group of healthy children and children with cerebral palsy were measured using a Vicon MoCap system. The kinematic data was recorded and the OpenSim software system was used to identify the joint angles, muscle-tendon forces and joint muscle moment, which are presented graphically with time diagrams. The musculus gastrocnemius medialis that is often studied in the context of cerebral palsy have been chosen to study the method of prediction. The diagrams of mean muscle-tendon force and mean moment are plotted and the data about the force-time and moment-time dependencies are used for training neural networks. The new way of prediction of muscle-tendon forces and moments based on neural networks was tested. Neural networks predicted the muscle forces and moments of healthy children and children with cerebral palsy. The designed method of prediction by neural networks could help to identify the difference between muscle behavior of healthy subjects and diseased subjects.

Electroactive polymer and shape memory alloy actuators in biomimetics and humanoids

NASA Astrophysics Data System (ADS)

Tadesse, Yonas

2013-04-01

There is a strong need to replicate natural muscles with artificial materials as the structure and function of natural muscle is optimum for articulation. Particularly, the cylindrical shape of natural muscle fiber and its interconnected structure promote the critical investigation of artificial muscles geometry and implementation in the design phase of certain platforms. Biomimetic robots and Humanoid Robot heads with Facial Expressions (HRwFE) are some of the typical platforms that can be used to study the geometrical effects of artificial muscles. It has been shown that electroactive polymer and shape memory alloy artificial muscles and their composites are some of the candidate materials that may replicate natural muscles and showed great promise for biomimetics and humanoid robots. The application of these materials to these systems reveals the challenges and associated technologies that need to be developed in parallel. This paper will focus on the computer aided design (CAD) models of conductive polymer and shape memory alloys in various biomimetic systems and Humanoid Robot with Facial Expressions (HRwFE). The design of these systems will be presented in a comparative manner primarily focusing on three critical parameters: the stress, the strain and the geometry of the artificial muscle.

An artificial EMG generation model based on signal-dependent noise and related application to motion classification

PubMed Central

Hayashi, Hideaki; Nakamura, Go; Chin, Takaaki; Tsuji, Toshio

2017-01-01

This paper proposes an artificial electromyogram (EMG) signal generation model based on signal-dependent noise, which has been ignored in existing methods, by introducing the stochastic construction of the EMG signals. In the proposed model, an EMG signal variance value is first generated from a probability distribution with a shape determined by a commanded muscle force and signal-dependent noise. Artificial EMG signals are then generated from the associated Gaussian distribution with a zero mean and the generated variance. This facilitates representation of artificial EMG signals with signal-dependent noise superimposed according to the muscle activation levels. The frequency characteristics of the EMG signals are also simulated via a shaping filter with parameters determined by an autoregressive model. An estimation method to determine EMG variance distribution using rectified and smoothed EMG signals, thereby allowing model parameter estimation with a small number of samples, is also incorporated in the proposed model. Moreover, the prediction of variance distribution with strong muscle contraction from EMG signals with low muscle contraction and related artificial EMG generation are also described. The results of experiments conducted, in which the reproduction capability of the proposed model was evaluated through comparison with measured EMG signals in terms of amplitude, frequency content, and EMG distribution demonstrate that the proposed model can reproduce the features of measured EMG signals. Further, utilizing the generated EMG signals as training data for a neural network resulted in the classification of upper limb motion with a higher precision than by learning from only measured EMG signals. This indicates that the proposed model is also applicable to motion classification. PMID:28640883

High Performance Artificial Muscles Using Nanofiber and Hybrid Yarns

DTIC Science & Technology

2015-07-14

provide 3.2% energy conversion efficiency (twice that of our CNT fiber muscles and 10X that of conducting polymer muscles ). They maintain stroke without...rubber dielectric muscle layer in twisted fiber drives torsional actuation. (2) One hundred times higher torsional stroke per muscle length...artificial muscles that provide giant stroke, fast response, high force generation, and long cycle life while optimizing energy conversion efficiencies

Feasibility of EMG-Based Control of Shoulder Muscle FNS Via Artificial Neural Network

DTIC Science & Technology

2001-10-25

assuming that just two paralyzed muscles (pectoralis major and latissimus dorsi ) were stimulated. Further, the needed activations of these “stimulated...injuries at C5-C6 typically result in paralysis of several important shoulder muscles (e.g., pectoralis major, latissimus dorsi , and serratus anterior...of several important muscles (e.g., pectoralis major and latissimus dorsi ),but retain at least partial voluntary control over a number of other

Artificial Muscle Kits for the Classroom

NASA Technical Reports Server (NTRS)

2004-01-01

Commonly referred to as "artificial muscles," electroactive polymer (EAP) materials are lightweight strips of highly flexible plastic that bend or stretch when subjected to electric voltage. EAP materials may prove to be a substitution for conventional actuation components such as motors and gears. Since the materials behave similarly to biological muscles, this emerging technology has the potential to develop improved prosthetics and biologically-inspired robots, and may even one day replace damaged human muscles. The practical application of artificial muscles provides a challenge, however, since the material requires improved effectiveness and durability before it can fulfill its potential.

Dynamic contraction behaviour of pneumatic artificial muscle

NASA Astrophysics Data System (ADS)

Doumit, Marc D.; Pardoel, Scott

2017-07-01

The development of a dynamic model for the Pneumatic Artificial Muscle (PAM) is an imperative undertaking for understanding and analyzing the behaviour of the PAM as a function of time. This paper proposes a Newtonian based dynamic PAM model that includes the modeling of the muscle geometry, force, inertia, fluid dynamic, static and dynamic friction, heat transfer and valve flow while ignoring the effect of bladder elasticity. This modeling contribution allows the designer to predict, analyze and optimize PAM performance prior to its development. Thus advancing successful implementations of PAM based powered exoskeletons and medical systems. To date, most muscle dynamic properties are determined experimentally, furthermore, no analytical models that can accurately predict the muscle's dynamic behaviour are found in the literature. Most developed analytical models adequately predict the muscle force in static cases but neglect the behaviour of the system in the transient response. This could be attributed to the highly challenging task of deriving such a dynamic model given the number of system elements that need to be identified and the system's highly non-linear properties. The proposed dynamic model in this paper is successfully simulated through MATLAB programing and validated the pressure, contraction distance and muscle temperature with experimental testing that is conducted with in-house built prototype PAM's.

Conducting polymer actuators: From basic concepts to proprioceptive systems

NASA Astrophysics Data System (ADS)

Martinez Gil, Jose Gabriel

Designers and engineers have been dreaming for decades of motors sensing, by themselves, working and surrounding conditions, as biological muscles do originating proprioception. Here bilayer full polymeric artificial muscles were checked up to very high cathodic potential limits (-2.5 V) in aqueous solution by cyclic voltammetry. The electrochemical driven exchange of ions from the conducting polymer film, and the concomitant Faradaic bending movement of the muscle, takes place in the full studied potential range. The presence of trapped counterion after deep reduction was corroborated by EDX determinations giving quite high electronic conductivity to the device. The large bending movement was used as a tool to quantify the amount of water exchanged per reaction unit (exchanged electron or ion). The potential evolutions of self-supported films of conducting polymers or conducting polymers (polypyrrole, polyaniline) coating different microfibers, during its oxidation/reduction senses working mechanical, thermal, chemical or electrical variables. The evolution of the muscle potential from electrochemical artificial muscles based on electroactive materials such as intrinsically conducting polymers and driven by constant currents senses, while working, any variation of the mechanical (trailed mass, obstacles, pressure, strain or stress), thermal or chemical conditions of work. One physically uniform artificial muscle includes one electrochemical motor and several sensors working simultaneously under the same driving reaction. Actuating (current and charge) and sensing (potential and energy) magnitudes are present, simultaneously, in the only two connecting wires and can be read by the computer at any time. From basic polymeric, mechanical and electrochemical principles a physicochemical equation describing artificial proprioception has been developed. It includes and describes, simultaneously, the evolution of the muscle potential during actuation as a function of the motor characteristics (rate and sense of the movement, relative position, and required energy) and the working variables (temperature, electrolyte concentration, mechanical conditions and driving current). By changing working conditions experimental results overlap theoretical predictions. The ensemble computer-generator-muscle-theoretical equation constitutes and describes artificial mechanical, thermal and chemical proprioception of the system. Proprioceptive tools and most intelligent zoomorphic or anthropomorphic soft robots can be envisaged.

Fuel-powered artificial muscles.

PubMed

Ebron, Von Howard; Yang, Zhiwei; Seyer, Daniel J; Kozlov, Mikhail E; Oh, Jiyoung; Xie, Hui; Razal, Joselito; Hall, Lee J; Ferraris, John P; Macdiarmid, Alan G; Baughman, Ray H

2006-03-17

Artificial muscles and electric motors found in autonomous robots and prosthetic limbs are typically battery-powered, which severely restricts the duration of their performance and can necessitate long inactivity during battery recharge. To help solve these problems, we demonstrated two types of artificial muscles that convert the chemical energy of high-energy-density fuels to mechanical energy. The first type stores electrical charge and uses changes in stored charge for mechanical actuation. In contrast with electrically powered electrochemical muscles, only half of the actuator cycle is electrochemical. The second type of fuel-powered muscle provides a demonstrated actuator stroke and power density comparable to those of natural skeletal muscle and generated stresses that are over a hundred times higher.

A strong integrated strength and toughness artificial nacre based on dopamine cross-linked graphene oxide.

PubMed

Cui, Wei; Li, Mingzhu; Liu, Jiyang; Wang, Ben; Zhang, Chuck; Jiang, Lei; Cheng, Qunfeng

2014-09-23

Demands of the strong integrated materials have substantially increased across various industries. Inspired by the relationship of excellent integration of mechanical properties and hierarchical nano/microscale structure of the natural nacre, we have developed a strategy for fabricating the strong integrated artificial nacre based on graphene oxide (GO) sheets by dopamine cross-linking via evaporation-induced assembly process. The tensile strength and toughness simultaneously show 1.5 and 2 times higher than that of natural nacre. Meanwhile, the artificial nacre shows high electrical conductivity. This type of strong integrated artificial nacre has great potential applications in aerospace, flexible supercapacitor electrodes, artificial muscle, and tissue engineering.

Microfluidic-enhanced 3D bioprinting of aligned myoblast-laden hydrogels leads to functionally organized myofibers in vitro and in vivo.

PubMed

Costantini, Marco; Testa, Stefano; Mozetic, Pamela; Barbetta, Andrea; Fuoco, Claudia; Fornetti, Ersilia; Tamiro, Francesco; Bernardini, Sergio; Jaroszewicz, Jakub; Święszkowski, Wojciech; Trombetta, Marcella; Castagnoli, Luisa; Seliktar, Dror; Garstecki, Piotr; Cesareni, Gianni; Cannata, Stefano; Rainer, Alberto; Gargioli, Cesare

2017-07-01

We present a new strategy for the fabrication of artificial skeletal muscle tissue with functional morphologies based on an innovative 3D bioprinting approach. The methodology is based on a microfluidic printing head coupled to a co-axial needle extruder for high-resolution 3D bioprinting of hydrogel fibers laden with muscle precursor cells (C2C12). To promote myogenic differentiation, we formulated a tailored bioink with a photocurable semi-synthetic biopolymer (PEG-Fibrinogen) encapsulating cells into 3D constructs composed of aligned hydrogel fibers. After 3-5 days of culture, the encapsulated myoblasts started migrating and fusing, forming multinucleated myotubes within the 3D bioprinted fibers. The obtained myotubes showed high degree of alignment along the direction of hydrogel fiber deposition, further revealing maturation, sarcomerogenesis, and functionality. Following subcutaneous implantation in the back of immunocompromised mice, bioprinted constructs generated organized artificial muscle tissue in vivo. Finally, we demonstrate that our microfluidic printing head allows to design three dimensional multi-cellular assemblies with an exquisite compartmentalization of the encapsulated cells. Our results demonstrate an enhanced myogenic differentiation with the formation of parallel aligned long-range myotubes. The approach that we report here represents a robust and valid candidate for the fabrication of macroscopic artificial muscle to scale up skeletal muscle tissue engineering for human clinical application. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Control of non-linear actuator of artificial muscles for the use in low-cost robotics prosthetics limbs

NASA Astrophysics Data System (ADS)

Anis Atikah, Nurul; Yeng Weng, Leong; Anuar, Adzly; Chien Fat, Chau; Sahari, Khairul Salleh Mohamed; Zainal Abidin, Izham

2017-10-01

Currently, the methods of actuating robotic-based prosthetic limbs are moving away from bulky actuators to more fluid materials such as artificial muscles. The main disadvantages of these artificial muscles are their high cost of manufacturing, low-force generation, cumbersome and complex controls. A recent discovery into using super coiled polymer (SCP) proved to have low manufacturing costs, high force generation, compact and simple controls. Nevertheless, the non-linear controls still exists due to the nature of heat-based actuation, which is hysteresis. This makes position control difficult. Using electrically conductive devices allows for very quick heating, but not quick cooling. This research tries to solve the problem by using peltier devices, which can effectively heat and cool the SCP, hence giving way to a more precise control. The peltier device does not actively introduce more energy to a volume of space, which the coiled heating does; instead, it acts as a heat pump. Experiments were conducted to test the feasibility of using peltier as an actuating method on different diameters of nylon fishing strings. Based on these experiments, the performance characteristics of the strings were plotted, which could be used to control the actuation of the string efficiently in the future.

Knitting and weaving artificial muscles

PubMed Central

Maziz, Ali; Concas, Alessandro; Khaldi, Alexandre; Stålhand, Jonas; Persson, Nils-Krister; Jager, Edwin W. H.

2017-01-01

A need exists for artificial muscles that are silent, soft, and compliant, with performance characteristics similar to those of skeletal muscle, enabling natural interaction of assistive devices with humans. By combining one of humankind’s oldest technologies, textile processing, with electroactive polymers, we demonstrate here the feasibility of wearable, soft artificial muscles made by weaving and knitting, with tunable force and strain. These textile actuators were produced from cellulose yarns assembled into fabrics and coated with conducting polymers using a metal-free deposition. To increase the output force, we assembled yarns in parallel by weaving. The force scaled linearly with the number of yarns in the woven fabric. To amplify the strain, we knitted a stretchable fabric, exhibiting a 53-fold increase in strain. In addition, the textile construction added mechanical stability to the actuators. Textile processing permits scalable and rational production of wearable artificial muscles, and enables novel ways to design assistive devices. PMID:28138542

Variable recruitment fluidic artificial muscles: modeling and experiments

NASA Astrophysics Data System (ADS)

Bryant, Matthew; Meller, Michael A.; Garcia, Ephrahim

2014-07-01

We investigate taking advantage of the lightweight, compliant nature of fluidic artificial muscles to create variable recruitment actuators in the form of artificial muscle bundles. Several actuator elements at different diameter scales are packaged to act as a single actuator device. The actuator elements of the bundle can be connected to the fluidic control circuit so that different groups of actuator elements, much like individual muscle fibers, can be activated independently depending on the required force output and motion. This novel actuation concept allows us to save energy by effectively impedance matching the active size of the actuators on the fly based on the instantaneous required load. This design also allows a single bundled actuator to operate in substantially different force regimes, which could be valuable for robots that need to perform a wide variety of tasks and interact safely with humans. This paper proposes, models and analyzes the actuation efficiency of this actuator concept. The analysis shows that variable recruitment operation can create an actuator that reduces throttling valve losses to operate more efficiently over a broader range of its force-strain operating space. We also present preliminary results of the design, fabrication and experimental characterization of three such bioinspired variable recruitment actuator prototypes.

Rotating turkeys and self-commutating artificial muscle motors

NASA Astrophysics Data System (ADS)

O'Brien, Benjamin M.; McKay, Thomas G.; Gisby, Todd A.; Anderson, Iain A.

2012-02-01

Electrostatic motors—first used by Benjamin Franklin to rotisserie a turkey—are making a comeback in the form of high energy density dielectric elastomer artificial muscles. We present a self-commutated artificial muscle motor that uses dielectric elastomer switches in the place of bulky external electronics. The motor simply requires a DC input voltage to rotate a shaft (0.73 Nm/kg, 0.24 Hz) and is a step away from hard metallic electromagnetic motors towards a soft, light, and printable future.

Biologically inspired toys using artificial muscles

NASA Technical Reports Server (NTRS)

Bar-Cohen, Y.

2001-01-01

Recent developments in electroactive polymers, so-called artificial muscles, could one day be used to make bionics possible. Meanwhile, as this technology evolves novel mechanisms are expected to emerge that are biologically inspired.

A validated finite element model of a soft artificial muscle motor

NASA Astrophysics Data System (ADS)

Tse, Tony Chun H.; O'Brien, Benjamin; McKay, Thomas; Anderson, Iain A.

2011-04-01

The Biomimetics Laboratory has developed a soft artificial muscle motor based on Dielectric Elastomers. The motor, 'Flexidrive', is light-weight and has low system complexity. It works by gripping and turning a shaft with a soft gear, like we would with our fingers. The motor's performance depends on many factors, such as actuation waveform, electrode patterning, geometries and contact tribology between the shaft and gear. We have developed a finite element model (FEM) of the motor as a study and design tool. Contact interaction was integrated with previous material and electromechanical coupling models in ABAQUS. The model was experimentally validated through a shape and blocked force analysis.

Artificial muscles on heat

NASA Astrophysics Data System (ADS)

McKay, Thomas G.; Shin, Dong Ki; Percy, Steven; Knight, Chris; McGarry, Scott; Anderson, Iain A.

2014-03-01

Many devices and processes produce low grade waste heat. Some of these include combustion engines, electrical circuits, biological processes and industrial processes. To harvest this heat energy thermoelectric devices, using the Seebeck effect, are commonly used. However, these devices have limitations in efficiency, and usable voltage. This paper investigates the viability of a Stirling engine coupled to an artificial muscle energy harvester to efficiently convert heat energy into electrical energy. The results present the testing of the prototype generator which produced 200 μW when operating at 75°C. Pathways for improved performance are discussed which include optimising the electronic control of the artificial muscle, adjusting the mechanical properties of the artificial muscle to work optimally with the remainder of the system, good sealing, and tuning the resonance of the displacer to minimise the power required to drive it.

Effect of mechanical load on the shuttling operation of molecular muscles

NASA Astrophysics Data System (ADS)

Lee, Seungjun; Lu, Wei

2009-06-01

We use molecular dynamics simulations to investigate the effect of mechanical force on stimulus-induced deformation of rotaxane-based artificial molecular muscles. The study shows that a small external force slows down the shuttling motion and leads to longer actuation time for a muscle to reach its full extension. Further increase in the force can significantly reduce the traveling distance of the ring, leading to reduced strain output. A force larger than 28 pN can completely suppress the shuttling motion, suggesting a limit of force output of molecular muscles.

Improving actuation efficiency through variable recruitment hydraulic McKibben muscles: modeling, orderly recruitment control, and experiments.

PubMed

Meller, Michael; Chipka, Jordan; Volkov, Alexander; Bryant, Matthew; Garcia, Ephrahim

2016-11-03

Hydraulic control systems have become increasingly popular as the means of actuation for human-scale legged robots and assistive devices. One of the biggest limitations to these systems is their run time untethered from a power source. One way to increase endurance is by improving actuation efficiency. We investigate reducing servovalve throttling losses by using a selective recruitment artificial muscle bundle comprised of three motor units. Each motor unit is made up of a pair of hydraulic McKibben muscles connected to one servovalve. The pressure and recruitment state of the artificial muscle bundle can be adjusted to match the load in an efficient manner, much like the firing rate and total number of recruited motor units is adjusted in skeletal muscle. A volume-based effective initial braid angle is used in the model of each recruitment level. This semi-empirical model is utilized to predict the efficiency gains of the proposed variable recruitment actuation scheme versus a throttling-only approach. A real-time orderly recruitment controller with pressure-based thresholds is developed. This controller is used to experimentally validate the model-predicted efficiency gains of recruitment on a robot arm. The results show that utilizing variable recruitment allows for much higher efficiencies over a broader operating envelope.

Three-Dimensional Human iPSC-Derived Artificial Skeletal Muscles Model Muscular Dystrophies and Enable Multilineage Tissue Engineering.

PubMed

Maffioletti, Sara Martina; Sarcar, Shilpita; Henderson, Alexander B H; Mannhardt, Ingra; Pinton, Luca; Moyle, Louise Anne; Steele-Stallard, Heather; Cappellari, Ornella; Wells, Kim E; Ferrari, Giulia; Mitchell, Jamie S; Tyzack, Giulia E; Kotiadis, Vassilios N; Khedr, Moustafa; Ragazzi, Martina; Wang, Weixin; Duchen, Michael R; Patani, Rickie; Zammit, Peter S; Wells, Dominic J; Eschenhagen, Thomas; Tedesco, Francesco Saverio

2018-04-17

Generating human skeletal muscle models is instrumental for investigating muscle pathology and therapy. Here, we report the generation of three-dimensional (3D) artificial skeletal muscle tissue from human pluripotent stem cells, including induced pluripotent stem cells (iPSCs) from patients with Duchenne, limb-girdle, and congenital muscular dystrophies. 3D skeletal myogenic differentiation of pluripotent cells was induced within hydrogels under tension to provide myofiber alignment. Artificial muscles recapitulated characteristics of human skeletal muscle tissue and could be implanted into immunodeficient mice. Pathological cellular hallmarks of incurable forms of severe muscular dystrophy could be modeled with high fidelity using this 3D platform. Finally, we show generation of fully human iPSC-derived, complex, multilineage muscle models containing key isogenic cellular constituents of skeletal muscle, including vascular endothelial cells, pericytes, and motor neurons. These results lay the foundation for a human skeletal muscle organoid-like platform for disease modeling, regenerative medicine, and therapy development. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Torsional Carbon Nanotube Artificial Muscles

NASA Astrophysics Data System (ADS)

Foroughi, Javad; Spinks, Geoffrey M.; Wallace, Gordon G.; Oh, Jiyoung; Kozlov, Mikhail E.; Fang, Shaoli; Mirfakhrai, Tissaphern; Madden, John D. W.; Shin, Min Kyoon; Kim, Seon Jeong; Baughman, Ray H.

2011-10-01

Rotary motors of conventional design can be rather complex and are therefore difficult to miniaturize; previous carbon nanotube artificial muscles provide contraction and bending, but not rotation. We show that an electrolyte-filled twist-spun carbon nanotube yarn, much thinner than a human hair, functions as a torsional artificial muscle in a simple three-electrode electrochemical system, providing a reversible 15,000° rotation and 590 revolutions per minute. A hydrostatic actuation mechanism, as seen in muscular hydrostats in nature, explains the simultaneous occurrence of lengthwise contraction and torsional rotation during the yarn volume increase caused by electrochemical double-layer charge injection. The use of a torsional yarn muscle as a mixer for a fluidic chip is demonstrated.

Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors

NASA Astrophysics Data System (ADS)

Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C. A.; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L.

2018-02-01

A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large proteins, in which mechanical stress induces a coordinated movement. However, artificial molecular muscles have often relied on covalent polymer-based actuators. Here, we describe the macroscopic contractile muscle-like motion of a supramolecular system (comprising 95% water) formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor. The molecular motor first assembles into nanofibres, which further assemble into aligned bundles that make up centimetre-long strings. Irradiation induces rotary motion of the molecular motors, and propagation and accumulation of this motion lead to contraction of the fibres towards the light source. This system supports large-amplitude motion, fast response, precise control over shape, as well as weight-lifting experiments in water and air.

Bio-inspired Hybrid Carbon Nanotube Muscles

NASA Astrophysics Data System (ADS)

Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

2016-05-01

There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

Biologically inspired technologies using artificial muscles

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2005-01-01

One of the newest fields of biomimetics is the electroactive polymers (EAP) that are also known as artificial muscles. To take advantage of these materials, efforts are made worldwide to establish a strong infrastructure addressing the need for comprehensive analytical modeling of their response mechanism and develop effective processing and characterization techniques. The field is still in its emerging state and robust materials are still not readily available however in recent years significant progress has been made and commercial products have already started to appear. This paper covers the current state of- the-art and challenges to making artificial muscles and their potential biomimetic applications.

The influence of altered working-side occlusal guidance on masticatory muscles and related jaw movement.

PubMed

Belser, U C; Hannam, A G

1985-03-01

The effect of four different occlusal situations (group function, canine guidance, working side occlusal interference, and hyperbalancing occlusal interference) on EMG activity in jaw elevator muscles and related mandibular movement was investigated on 12 subjects. With a computer-based system, EMG and displacement signals were collected simultaneously during specific functional (unilateral chewing) and parafunctional tasks (mandibular gliding movements and various tooth clenching efforts) and analyzed quantitatively. When a naturally acquired group function was temporarily and artificially changed into a dominant canine guidance, a significant general reduction of elevator muscle activity was observed when subjects exerted full isometric tooth-clenching efforts in a lateral mandibular position. The original muscular coordination pattern (relative contraction from muscle to muscle) remained unaltered during this test. With respect to unilateral chewing, no significant alterations in the activity or coordination of the muscles occurred when an artificial canine guidance was introduced. Introduction of a hyperbalancing occlusal contact caused significant alterations in muscle activity and coordination during maximal tooth clenching in a lateral mandibular position. A marked shift of temporal muscle EMG activity toward the side of the interference and unchanged bilateral activity of the two masseter muscles were observed. The results suggest that canine-protected occlusions do not significantly alter muscle activity during mastication but significantly reduce muscle activity during parafunctional clenching. They also suggest that non-working side contacts dramatically alter the distribution of muscle activity during parafunctional clenching, and that this redistribution may affect the nature of reaction forces at the temporomandibular joints.

Selected papers from the 7th International Conference on Biomimetics, Artificial Muscles and Nano-bio (BAMN2013)

NASA Astrophysics Data System (ADS)

Shahinpoor, Mohsen; Oh, Ilkwon

2014-07-01

The 7th International Congress on Biomimetics, Artificial Muscles and Nano-Bio was held on the magnificent and beautiful Jeju Island in Korea on 26-30 August 2013. In June 2007, the volcanic island and lava tube cave systems were designated as UNESCO World Natural Heritage Sites for their natural beauty and unique geographical values. The aim of the congress was to offer high-level lectures, extensive discussions and communications covering the state-of-the-art on biomimetics, artificial muscles, and nano-bio technologies providing an overview of their potential applications in the industrial, biomedical, scientific and robotic fields. This conference provided a necessary platform for an ongoing dialogue between researchers from different areas (chemistry, physics, biology, medicine, engineering, robotics, etc) within biomimetics, artificial muscle and nano-bio technologies. This special issue of Smart Materials and Structures is devoted to a selected number of research papers that were presented at BAMN2013. Of the 400 or so papers and over 220 posters presented at this international congress, 15 papers were finally received, reviewed and accepted for this special issue, following the regular peer review procedures of the journal. The special issue covers polymeric artificial muscles, electroactive polymers, multifunctional nanocomposites, and their applications. In particular, electromechanical performance and other characteristics of ionic polymer-metal composites (IPMCs) fabricated with various commercially available ion exchange membranes are discussed. Additionally, the control of free-edge interlaminar stresses in composite laminates using piezoelectric actuators is elaborated on. Further, the electrode effects of a cellulose-based electroactive paper energy harvester are described. Next, a flexible tactile-feedback touch screen using transparent ferroelectric polymer film vibrators is discussed. A broad coverage of bio-applications of IPMC transducers is then presented followed by a discussion on a novel electroactive PVA-TOCN actuator extremely sensitive to low electrical inputs. Additionally, an experimental self-sensing technique for an IPMC actuator is described. This area was also covered in previous BAMN congresses in the context of electromechanical models for self-sensing IPMC actuating devices with patterned surface electrodes, where actuator and sensor elements are separated by a grounded shielding electrode. Eventually, an electromechanical model of the device has also been proposed and validated. Following that, broad coverage of the modeling of an IPMC actuator based on an extended Kalman filter trained by a neural network is presented. The realization of variable recruitment fluidic artificial muscles is next covered in the special issue followed by a discussion on soft and flexible PEDOT/PSS films for applications to soft actuators. Furthermore, coverage is presented on biomimetic FAA-certifiable, artificial muscle structures for commercial aircraft wings. Additional papers in this special issue cover technologies enhancing the thermal reliability of fiber-optic sensors for bio-inspired applications at ultra-high temperatures, a study on a saddle-shaped bi-stable morphing panel with SMA spring actuators, energy harvesting from a vortex ring on an annular IPMC and finally the development of a morphing flap using SMA actuators followed by an aerodynamic characterization of a morphing flap. We hope that this collection of articles will help to stimulate future work in this emerging field of research and generate new applications in biomimetics, artificial muscles and nano-bio science and technology. Acknowledgments We would like to thank all the authors for their contributions, and the Smart Materials and Structures Editor-in-Chief, Professor Ephrahim Garcia, for having accepted our proposal to organize this special issue. In particular, we are extremely grateful to the IOP Publishing team for their great support, with special thanks to Natasha Leeper and Bethan Davies for their excellent management in the preparation of this special issue. We are also indebted to all of the reviewers, and the editors and editorial staff who handled the reviews of all the papers.

A review on robotic fish enabled by ionic polymer-metal composite artificial muscles.

PubMed

Chen, Zheng

2017-01-01

A novel actuating material, which is lightweight, soft, and capable of generating large flapping motion under electrical stimuli, is highly desirable to build energy-efficient and maneuverable bio-inspired underwater robots. Ionic polymer-metal composites are important category of electroactive polymers, since they can generate large bending motions under low actuation voltages. IPMCs are ideal artificial muscles for small-scale and bio-inspired robots. This paper takes a system perspective to review the recent work on IPMC-enabled underwater robots, from modeling, fabrication, and bio-inspired design perspectives. First, a physics-based and control-oriented model of IPMC actuator will be reviewed. Second, a bio-inspired robotic fish propelled by IPMC caudal fin will be presented and a steady-state speed model of the fish will be demonstrated. Third, a novel fabrication process for 3D actuating membrane will be introduced and a bio-inspired robotic manta ray propelled by two IPMC pectoral fins will be demonstrated. Fourth, a 2D maneuverable robotic fish propelled by multiple IPMC fin will be presented. Last, advantages and challenges of using IPMC artificial muscles in bio-inspired robots will be concluded.

Cell-Based Therapies in Lower Urinary Tract Disorders.

PubMed

Gopinath, Chaitanya; Ponsaerts, Peter; Wyndaele, Jean Jacques

2015-01-01

Cell-based therapy for the bladder has its beginnings in the 1990s with the successful isolation and culture of bladder smooth muscle cells. Since then, several attempts have been made to artificially implant native cell types and stem cell-derived cells into damaged bladders in the form of single-cell injectables or as grafts seeded onto artificial extracellular matrix. We critically examined in the literature the types of cells and their probable role as an alternative to non-drug-based, non-bowel-based graft replacement therapy in disorders of the urinary bladder. The limitations and plausible improvements to these novel therapies have also been discussed, keeping in mind an ideal therapy that could suit most bladder abnormalities arising out of varied number of disorders. In conclusion, muscle-derived cell types have consistently proven to be a promising therapy to emerge in the coming decade. However, tissue-engineered constructs have yet to prove their success in preclinical and long-term clinical setting.

Braided artificial muscles: modeling and experimental validation

NASA Astrophysics Data System (ADS)

Dragan, Liliana; Cioban, Horia

2009-01-01

The paper presents a few graphical modalities for constructing the double helical braid, which is the basis for the braided artificial pneumatic muscles, by using specialized software applications. This represents the first stage in achieving the method of finite element analysis of this type of linear pneumatic actuator.

Proper muscle layer damage affects ulcer healing after gastric endoscopic submucosal dissection.

PubMed

Horikawa, Yohei; Mimori, Nobuya; Mizutamari, Hiroya; Kato, Yuhei; Shimazu, Kazuhiro; Sawaguchi, Masayuki; Tawaraya, Shin; Igarashi, Kimihiro; Okubo, Syunji

2015-11-01

Endoscopic submucosal dissection (ESD) is the established therapy for superficial gastrointestinal neoplasms. However, management of the artificial ulcers associated with ESD has become important and the relationship between ulcer healing factors and treatment is still unclear. We aimed to evaluate ESD-related artificial ulcer reduction ratio at 4 weeks to assess factors associating with ulcer healing after ESD that may lead to optimal treatment. Between January 2009 and December 2013, a total of 375 lesions fulfilled the expanded criteria for ESD. We defined ulcer reduction rate <90% as (A) poor-healing group; and rate ≥90% as (B) well-healing group. After exclusion, 328 lesions were divided into two groups and analyzed. These two groups were compared based on clinicopathological/endoscopic features, concomitant drugs, and treatment. Ulcer reduction rate was significantly correlated with factors related to the ESD procedure (i.e. procedure time, submucosal fibrosis, and injury of the proper muscle layer, in univariate analysis. Multivariate logistic regression analysis showed that submucosal fibrosis (F2) (P = 0.03; OR, 16.46; 95% CI, 1.31-206.73) and injury of the proper muscle layer (P = 0.01; OR, 4.27; 95% CI, 2.04-8.92) were statistically significant predictors of delayed healing. This single-center retrospective study indicated that ESD-induced artificial ulcer healing was affected by submucosal fibrosis and injury of the proper muscle layer, which induced damage to the muscle layer. Therefore, the preferable pharmacotherapy can be determined on completion of the ESD procedure. © 2015 The Authors Digestive Endoscopy © 2015 Japan Gastroenterological Endoscopy Society.

Induced formation and maturation of acetylcholine receptor clusters in a defined 3D bio-artificial muscle.

PubMed

Wang, Lin; Shansky, Janet; Vandenburgh, Herman

2013-12-01

Dysfunction of the neuromuscular junction is involved in a wide range of muscular diseases. The development of neuromuscular junction through which skeletal muscle is innervated requires the functional modulation of acetylcholine receptor (AchR) clustering on myofibers. However, studies on AchR clustering in vitro are mostly done on monolayer muscle cell culture, which lacks a three-dimensional (3D) structure, a prominent limitation of the two-dimensional (2D) system. To enable a better understanding on the structure-function correlation underlying skeletal muscle innervation, a muscle system with a well-defined geometry mimicking the in vivo muscular setting is needed. Here, we report a 3D bio-artificial muscle (BAM) bioengineered from green fluorescent protein-transduced C3H murine myoblasts as a novel in vitro tissue-based model for muscle innervation studies. Our cell biological and molecular analysis showed that this BAM is structurally similar to in vivo muscle tissue and can reach the perinatal differentiation stage, higher than does 2D culture. Effective clustering and morphological maturation of AchRs on BAMs induced by agrin and laminin indicate the functional activity and plasticity of this BAM system toward innervation. Taken together, our results show that the BAM provides a favorable 3D environment that at least partially recapitulates real physiological skeletal muscle with regard to innervation. With a convenience of fabrication and manipulation, this 3D in vitro system offers a novel model for studying mechanisms underlying skeletal muscle innervation and testing therapeutic strategies for relevant nervous and muscular diseases.

Biologically inspired technologies using artificial muscles

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph

2005-01-01

After billions of years of evolution, nature developed inventions that work, which are appropriate for the intended tasks and that last. The evolution of nature led to the introduction of highly effective and power efficient biological mechanisms that are scalable from micron to many meters in size. Imitating these mechanisms offers enormous potentials for the improvement of our life and the tools we use. Humans have always made efforts to imitate nature and we are increasingly reaching levels of advancement where it becomes significantly easier to imitate, copy, and adapt biological methods, processes and systems. Some of the biomimetic technologies that have emerged include artificial muscles, artificial intelligence, and artificial vision to which significant advances in materials science, mechanics, electronics, and computer science have contributed greatly. One of the newest fields of biomimetics is the electroactive polymers (EAP) that are also known as artificial muscles. To take advantage of these materials, efforts are made worldwide to establish a strong infrastructure addressing the need for comprehensive analytical modeling of their operation mechanism and develop effective processing and characterization techniques. The field is still in its emerging state and robust materials are not readily available however in recent years significant progress has been made and commercial products have already started to appear. This paper covers the state-of-the-art and challenges to making artificial muscles and their potential biomimetic applications.

Computer-based test-bed for clinical assessment of hand/wrist feed-forward neuroprosthetic controllers using artificial neural networks.

PubMed

Luján, J L; Crago, P E

2004-11-01

Neuroprosthestic systems can be used to restore hand grasp and wrist control in individuals with C5/C6 spinal cord injury. A computer-based system was developed for the implementation, tuning and clinical assessment of neuroprosthetic controllers, using off-the-shelf hardware and software. The computer system turned a Pentium III PC running Windows NT into a non-dedicated, real-time system for the control of neuroprostheses. Software execution (written using the high-level programming languages LabVIEW and MATLAB) was divided into two phases: training and real-time control. During the training phase, the computer system collected input/output data by stimulating the muscles and measuring the muscle outputs in real-time, analysed the recorded data, generated a set of training data and trained an artificial neural network (ANN)-based controller. During real-time control, the computer system stimulated the muscles using stimulus pulsewidths predicted by the ANN controller in response to a sampled input from an external command source, to provide independent control of hand grasp and wrist posture. System timing was stable, reliable and capable of providing muscle stimulation at frequencies up to 24Hz. To demonstrate the application of the test-bed, an ANN-based controller was implemented with three inputs and two independent channels of stimulation. The ANN controller's ability to control hand grasp and wrist angle independently was assessed by quantitative comparison of the outputs of the stimulated muscles with a set of desired grasp or wrist postures determined by the command signal. Controller performance results were mixed, but the platform provided the tools to implement and assess future controller designs.

Biomimetic artificial sphincter muscles: status and challenges

NASA Astrophysics Data System (ADS)

Leung, Vanessa; Fattorini, Elisa; Karapetkova, Maria; Osmani, Bekim; Töpper, Tino; Weiss, Florian; Müller, Bert

2016-04-01

Fecal incontinence is the involuntary loss of bowel content and affects more than 12% of the adult population, including 45% of retirement home residents. Severe fecal incontinence is often treated by implanting an artificial sphincter. Currently available implants, however, have long-term reoperation rates of 95% and definitive explantation rates of 40%. These statistics show that the implants fail to reproduce the capabilities of the natural sphincter and that the development of an adaptive, biologically inspired implant is required. Dielectric elastomer actuators (DEA) are being developed as artificial muscles for a biomimetic sphincter, due to their suitable response time, reaction forces, and energy consumption. However, at present the operation voltage of DEAs is too high for artificial muscles implanted in the human body. To reduce the operating voltage to tens of volts, we are using microfabrication to reduce the thickness of the elastomer layer to the nanometer level. Two microfabrication methods are being investigated: molecular beam deposition and electrospray deposition. This communication covers the current status and a perspective on the way forward, including the long-term prospects of constructing a smart sphincter from low-voltage sensors and actuators based on nanometer-thin dielectric elastomer films. As DEA can also provide sensory feedback, a biomimetic sphincter can be designed in accordance with the geometrical and mechanical parameters of its natural counterpart. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence du ring daily activities.

Artificial muscles driven by the cooperative actuation of electrochemical molecular machines. Persistent discrepancies and challenges

NASA Astrophysics Data System (ADS)

Otero

2017-10-01

Here we review the persisting conceptual discrepancies between different research groups working on artificial muscles based on conducting polymers and other electroactive material. The basic question is if they can be treated as traditional electro-mechanical (physical) actuators driven by electric fields and described by some adaptation of their physical models or if, replicating natural muscles, they are electro-chemo-mechanical actuators driven by electrochemical reaction of the constitutive molecular machines: the polymeric chains. In that case the charge consumed by the reaction will control the volume variation of the muscular material and the motor displacement, following the basic and single Faraday's laws: the charge consumed by the reaction determines the number of exchanged ions and solvent, the film volume variation to lodge/expel them and the amplitude of the movement. Deviations from the linear relationships are due to the osmotic exchange of solvent and to the presence of parallel reactions from the electrolyte, which originate creeping effects. Challenges and limitations are underlined.

A thin membrane artificial muscle rotary motor

NASA Astrophysics Data System (ADS)

Anderson, Iain A.; Hale, Thom; Gisby, Todd; Inamura, Tokushu; McKay, Thomas; O'Brien, Benjamin; Walbran, Scott; Calius, Emilio P.

2010-01-01

Desirable rotary motor attributes for robotics include the ability to develop high torque in a low mass body and to generate peak power at low rotational speeds. Electro-active polymer artificial muscles offer promise as actuator elements for robotic motors. A promising artificial muscle technology for use as a driving mechanism for rotary motion is the dielectric elastomer actuator (DEA). We present a membrane DEA motor in which phased actuation of electroded sectors of the motor membrane impart orbital motion to a central drive that turns a rotor. The motor is inherently scalable, flexible, flat, silent in operation, amenable to deposition-based manufacturing approaches, and uses relatively inexpensive materials. As a membrane it can also form part of the skin of a robot. We have investigated the torque and power of stacked membrane layers. Specific power and torque ratios when calculated using active membrane mass only were 20.8 W/kg and 4.1 Nm/kg, respectively. These numbers compare favorably with a commercially available stepper motor. Multi-membrane fabrication substantially boosts torque and power and increases the active mass of membrane relative to supporting framework. Through finite element modeling, we show the mechanisms governing the maximum torque the device can generate and how the motor can be improved.

Soft but Powerful Artificial Muscles Based on 3D Graphene-CNT-Ni Heteronanostructures.

PubMed

Kim, Jaehwan; Bae, Seok-Hu; Kotal, Moumita; Stalbaum, Tyler; Kim, Kwang J; Oh, Il-Kwon

2017-08-01

Bioinspired soft ionic actuators, which exhibit large strain and high durability under low input voltages, are regarded as prospective candidates for future soft electronics. However, due to the intrinsic drawback of weak blocking force, the feasible applications of soft ionic actuators are limited until now. An electroactive artificial muscle electro-chemomechanically reinforced with 3D graphene-carbon nanotube-nickel heteronanostructures (G-CNT-Ni) to improve blocking force and bending deformation of the ionic actuators is demonstrated. The G-CNT-Ni heteronanostructure, which provides an electrically conductive 3D network and sufficient contact area with mobile ions in the polymer electrolyte, is embedded as a nanofiller in both ionic polymer and conductive electrodes of the ionic actuators. An ionic exchangeable composite membrane consisting of Nafion, G-CNT-Ni and ionic liquid (IL) shows improved tensile modulus and strength of up to 166% and 98%, respectively, and increased ionic conductivity of 0.254 S m -1 . The ionic actuator exhibits enhanced actuation performances including three times larger bending deformation, 2.37 times higher blocking force, and 4 h durability. The electroactive artificial muscle electro-chemomechanically reinforced with 3D G-CNT-Ni heteronanostructures offers improvements over current soft ionic actuator technologies and can advance the practical engineering applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cerebellar-inspired algorithm for adaptive control of nonlinear dielectric elastomer-based artificial muscle

PubMed Central

Assaf, Tareq; Rossiter, Jonathan M.; Porrill, John

2016-01-01

Electroactive polymer actuators are important for soft robotics, but can be difficult to control because of compliance, creep and nonlinearities. Because biological control mechanisms have evolved to deal with such problems, we investigated whether a control scheme based on the cerebellum would be useful for controlling a nonlinear dielectric elastomer actuator, a class of artificial muscle. The cerebellum was represented by the adaptive filter model, and acted in parallel with a brainstem, an approximate inverse plant model. The recurrent connections between the two allowed for direct use of sensory error to adjust motor commands. Accurate tracking of a displacement command in the actuator's nonlinear range was achieved by either semi-linear basis functions in the cerebellar model or semi-linear functions in the brainstem corresponding to recruitment in biological muscle. In addition, allowing transfer of training between cerebellum and brainstem as has been observed in the vestibulo-ocular reflex prevented the steady increase in cerebellar output otherwise required to deal with creep. The extensibility and relative simplicity of the cerebellar-based adaptive-inverse control scheme suggests that it is a plausible candidate for controlling this type of actuator. Moreover, its performance highlights important features of biological control, particularly nonlinear basis functions, recruitment and transfer of training. PMID:27655667

Functional electrical stimulation controlled by artificial neural networks: pilot experiments with simple movements are promising for rehabilitation applications.

PubMed

Ferrante, Simona; Pedrocchi, Alessandra; Iannò, Marco; De Momi, Elena; Ferrarin, Maurizio; Ferrigno, Giancarlo

2004-01-01

This study falls within the ambit of research on functional electrical stimulation for the design of rehabilitation training for spinal cord injured patients. In this context, a crucial issue is the control of the stimulation parameters in order to optimize the patterns of muscle activation and to increase the duration of the exercises. An adaptive control system (NEURADAPT) based on artificial neural networks (ANNs) was developed to control the knee joint in accordance with desired trajectories by stimulating quadriceps muscles. This strategy includes an inverse neural model of the stimulated limb in the feedforward line and a neural network trained on-line in the feedback loop. NEURADAPT was compared with a linear closed-loop proportional integrative derivative (PID) controller and with a model-based neural controller (NEUROPID). Experiments on two subjects (one healthy and one paraplegic) show the good performance of NEURADAPT, which is able to reduce the time lag introduced by the PID controller. In addition, control systems based on ANN techniques do not require complicated calibration procedures at the beginning of each experimental session. After the initial learning phase, the ANN, thanks to its generalization capacity, is able to cope with a certain range of variability of skeletal muscle properties.

Use of Synergistic Interactions to Fabricate Strong, Tough, and Conductive Artificial Nacre Based on Graphene Oxide and Chitosan.

PubMed

Wan, Sijie; Peng, Jingsong; Li, Yuchen; Hu, Han; Jiang, Lei; Cheng, Qunfeng

2015-10-27

Graphene is the strongest and stiffest material, leading to the development of promising applications in many fields. However, the assembly of graphene nanosheets into macrosized nanocomposites for practical applications remains a challenge. Nacre in its natural form sets the "gold standard" for toughness and strength, which serves as a guide to the assembly of graphene nanosheets into high-performance nanocomposites. Here we show the strong, tough, conductive artificial nacre based on graphene oxide through synergistic interactions of hydrogen and covalent bonding. Tensile strength and toughness was 4 and 10 times higher, respectively, than that of natural nacre. The exceptional integrated strong and tough artificial nacre has promising applications in aerospace, artificial muscle, and tissue engineering, especially for flexible supercapacitor electrodes due to its high electrical conductivity. The use of synergistic interactions is a strategy for the development of high-performance nanocomposites.

Characterization and modeling of ionic polymeric smart materials as artificial muscles and robotic swimming structures

NASA Astrophysics Data System (ADS)

Mojarrad, Mehran

2001-07-01

In this dissertation document, a thorough review and investigation of works in connection with the ionic polymeric gels as artificial muscles and electrically controllable polymeric network structures were performed. Where possible, comparisons were made with biological muscles and applications in marine propulsion using such polymeric materials were investigated. Furthermore, methods of fabrication of several chemically active ionic polymeric gel muscles such as PolyAcryloNitrile (PAN), Poly(2-Acrylamido-2-Methyl-1-PropaneSulfonic) acid (PAMPS), and PolyAcrylic-acid-bis-AcrylaMide (PAAM) as well as a new class of electrically active composite muscle such as Ion-Exchange-Metal-Composites (IEMC) or Ionic Polymer Metal Composites (IPMC) materials are introduced and investigated that resulted in two US patents regarding their fabrication and application capabilities as actuators and sensors. In this research, various forms of the IPMC fabrication were explored and reported. In addition, characterization of PAN muscles, bundling and encapsulation were investigated. Conversion of chemical to electrical artificial muscles were also investigated using chemical plating techniques as well as physical vapor deposition methods of the pH-activated muscles like PAN fibers. Experimental methods were devised to characterize contraction, expansion, and bending of various actuators using isometric, isoionic, and isotonic characterization methods. Several apparatuses for modeling and testing of the various artificial muscles were built to show the viability of the application of both chemoactive and electroactive muscles. Furthermore PAN fiber muscles in different configurations such as spring-loaded fiber bundles, biceps, triceps, ribbon type muscles, and segmented fiber bundles were fabricated to make a variety of actuators. Additionally, swimming robotic structures and associated hardware were built to incorporate IPMC as biomimetic propulsion fin actuators. In addition, various configuration of IPMC such as linear actuators and multiplayer actuators were fabricated and evaluated for load and sensing capability. Theories associated with ionic polymer gels electrodynamics and chemodynamics were proposed, analyzed and modeled for the manufactured material. Futhermore, theoretical models of swimming structures were developed and compared with biological fish propulsion models and dynamically evaluated for robotic applications.

Newton Output Blocking Force under Low-Voltage Stimulation for Carbon Nanotube-Electroactive Polymer Composite Artificial Muscles.

PubMed

Chen, I-Wen Peter; Yang, Ming-Chia; Yang, Chia-Hui; Zhong, Dai-Xuan; Hsu, Ming-Chun; Chen, YiWen

2017-02-15

This is a study on the development of carbon nanotube-based composite actuators using a new ionic liquid-doped electroactive ionic polymer. For scalable production purposes, a simple hot-pressing method was used. Carbon nanotube/ionic liquid-Nafion/carbon nanotube composite films were fabricated that exhibited a large output blocking force and a stable cycling life with low alternating voltage stimuli in air. Of particular interest and importance, a blocking force of 1.5 N was achieved at an applied voltage of 6 V. Operational durability was confirmed by testing in air for over 30 000 cycles (or 43 h). The superior actuation performance of the carbon nanotube/ionic liquid-Nafion/carbon nanotube composite, coupled with easy manufacturability, low driving voltage, and reliable operation, promises great potential for artificial muscle and biomimetic applications.

Characterizing the Peano fluidic muscle and the effects of its geometry properties on its behavior

NASA Astrophysics Data System (ADS)

Veale, Allan Joshua; Xie, Sheng Quan; Anderson, Iain Alexander

2016-06-01

In this work, we explore the basic static and dynamic behavior of a hydraulically actuated Peano muscle and how its geometry affects key static and dynamic performance metrics. The Peano muscle, or pouch motor is a fluid powered artificial muscle. Similar to McKibben pneumatic artificial muscles (PAMs), it has the ability to generate the high forces of biological muscles with the low threshold pressure of pleated PAMs, but in a slim, easily distributed form. We found that Peano muscles have similar characteristics to other PAMs, but produce lower free-strains. A test rig capable of measuring high-speed flow rates with a Venturi tube revealed that their efficiency peaks at about 40% during highly dynamic movements. Peano muscles with more tubes and of a greater size do not move faster. Also, their muscle tubes should have an aspect ratio of at least 1:3 and channel width greater than 20% to maximize performance. These findings suggest that finite element modeling be used to optimize more complex Peano muscle geometries.

Hydraulically actuated artificial muscles

NASA Astrophysics Data System (ADS)

Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

2012-04-01

Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

Biodegradable and edible gelatine actuators for use as artificial muscles

NASA Astrophysics Data System (ADS)

Chambers, L. D.; Winfield, J.; Ieropoulos, I.; Rossiter, J.

2014-03-01

The expense and use of non-recyclable materials often requires the retrieval and recovery of exploratory robots. Therefore, conventional materials such as plastics and metals in robotics can be limiting. For applications such as environmental monitoring, a fully biodegradable or edible robot may provide the optimum solution. Materials that provide power and actuation as well as biodegradability provide a compelling dimension to future robotic systems. To highlight the potential of novel biodegradable and edible materials as artificial muscles, the actuation of a biodegradable hydrogel was investigated. The fabricated gelatine based polymer gel was inexpensive, easy to handle, biodegradable and edible. The electro-mechanical performance was assessed using two contactless, parallel stainless steel electrodes immersed in 0.1M NaOH solution and fixed 40 mm apart with the strip actuator pinned directly between the electrodes. The actuation displacement in response to a bias voltage was measured over hydration/de-hydration cycles. Long term (11 days) and short term (1 hour) investigations demonstrated the bending behaviour of the swollen material in response to an electric field. Actuation voltage was low (<10 V) resulting in a slow actuation response with large displacement angles (<55 degrees). The stability of the immersed material decreased within the first hour due to swelling, however, was recovered on de-hydrating between actuations. The controlled degradation of biodegradable and edible artificial muscles could help to drive the development of environmentally friendly robotics.

Advancing the frontiers of silk fibroin protein-based materials for futuristic electronics and clinical wound-healing (Invited review).

PubMed

Koh, Leng-Duei; Yeo, Jingjie; Lee, Yeong Yuh; Ong, Qunya; Han, Mingyong; Tee, Benjamin C-K

2018-05-01

The present review will introduce the basic concepts of silk-based electronics/optoelectronics including the latest technological advances on the use of silk fibroin in combination with other functional components, with an emphasis on improving the performance of next-generation silk-based materials. It also highlights the patterning of silk fibroin to produce micro/nano-scale features, as well as the functionalization of silk fibroin to impart antimicrobial (i.e. antibacterial) properties. Silk-based bioelectronics have great potential for advanced or futuristic bio-applications including e-skins, e-bandages, biosensors, wearable displays, implantable devices, artificial muscles, etc. Notably, silk-based organic field-effect transistors have highly promising applications in e-skins and biosensors; silk-based electrodes/antennas are used for in vivo bioanalysis or sensing purpose (e.g., measurement of neurotransmitter such as dopamine) in addition to their use as food sensors; silk-based diodes can be applied as light sources for wound healing or tissue engineering, e.g., in cutaneous wound closure or induction of photothrombosis of corneal neovascularization; silk-based actuators have promising applications as artificial muscles; whereas silk-based memristors have exciting applications as logic or synaptic network for realizing e-skins or bionic brains. Copyright © 2018 Elsevier B.V. All rights reserved.

Empirical modeling of dynamic behaviors of pneumatic artificial muscle actuators.

PubMed

Wickramatunge, Kanchana Crishan; Leephakpreeda, Thananchai

2013-11-01

Pneumatic Artificial Muscle (PAM) actuators yield muscle-like mechanical actuation with high force to weight ratio, soft and flexible structure, and adaptable compliance for rehabilitation and prosthetic appliances to the disabled as well as humanoid robots or machines. The present study is to develop empirical models of the PAM actuators, that is, a PAM coupled with pneumatic control valves, in order to describe their dynamic behaviors for practical control design and usage. Empirical modeling is an efficient approach to computer-based modeling with observations of real behaviors. Different characteristics of dynamic behaviors of each PAM actuator are due not only to the structures of the PAM actuators themselves, but also to the variations of their material properties in manufacturing processes. To overcome the difficulties, the proposed empirical models are experimentally derived from real physical behaviors of the PAM actuators, which are being implemented. In case studies, the simulated results with good agreement to experimental results, show that the proposed methodology can be applied to describe the dynamic behaviors of the real PAM actuators. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Control approach development for variable recruitment artificial muscles

NASA Astrophysics Data System (ADS)

Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-04-01

This study characterizes hybrid control approaches for the variable recruitment of fluidic artificial muscles with double acting (antagonistic) actuation. Fluidic artificial muscle actuators have been explored by researchers due to their natural compliance, high force-to-weight ratio, and low cost of fabrication. Previous studies have attempted to improve system efficiency of the actuators through variable recruitment, i.e. using discrete changes in the number of active actuators. While current variable recruitment research utilizes manual valve switching, this paper details the current development of an online variable recruitment control scheme. By continuously controlling applied pressure and discretely controlling the number of active actuators, operation in the lowest possible recruitment state is ensured and working fluid consumption is minimized. Results provide insight into switching control scheme effects on working fluids, fabrication material choices, actuator modeling, and controller development decisions.

Electrodynamic smooth muscle sphincter: development and biomechanical evaluation of a novel porcine artificial smooth muscle sphincter in a new in vitro stoma simulator.

PubMed

Schrag, H J; Karwath, D; Grub, C; Fragoza Padilla, F; Noack, T; Hopt, U T

2005-07-01

Many authors have suggested that the activity of the enteric inhibitory nerves is important in regulating normal gastrointestinal motility and inducing smooth muscle relaxation. Hitherto, no experimental or clinical models exist that transfer these physiological aspects to creating an autologous artificial sphincter for the treatment of major incontinence. Therefore, this study was performed to determine the contractile and relaxant capacity of gastrointestinal muscle types and to investigate the efficiency of a novel smooth muscle sphincter, based on the non-adrenergic, non-cholinergic (NANC) receptive relaxation under electrical field stimulation (EFS). For the first step, the isometric tension from isolated circular porcine fundus and colon muscle strips was recorded during pharmacological stimulation (TTX, L-NNA and atropine) and EFS. As a result, a continent electrodynamic smooth muscle sphincter (ESMS) was created by wrapping a fundus muscle flap around an isolated segment of porcine distal colon. The EFS of the free nerve fibers of the flap was realized using a circular platinum wire electrode. Parameters such as threshold of continence, intra/preluminal pressure and fluid passage were analyzed in a newly designed in vitro stoma simulator. Electrical field stimulation produced a maximal and voltage-dependent fundus relaxation to --12.4 mN/mm(2) (frequency of 40 Hz, pulse duration, train duration and voltage of 5 ms, 1 s and 60 mA respectively), which were abolished by N-nitro-L -arginine (L-NNA; 10(-4) M) in a dose-dependent manner, confirming that relaxant responses were mediated by NANC nerves. The results of eight ESMS showed that circular electrical stimulation of the muscle flap caused muscle relaxation with a concomitant and effective reduction in the occlusion pressure. The NANC-induced relaxation mechanism of porcine fundus preparations could be transferred to an efficient smooth muscle sphincter with a high threshold of continence and electrically controlled defecation.

Material and fabrication strategies for artificial muscles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Spinks, Geoffrey M.

2017-04-01

Soft robotic and wearable robotic devices seek to exploit polymer based artificial muscles and sensor materials to generate biomimetic movements and forces. A challenge is to integrate the active materials into a complex, three-dimensional device with integrated electronics, power supplies and support structures. Both 3D printing and textiles technologies offer attractive fabrication strategies, but require suitable functional materials. 3D printing of actuating hydrogels has been developed to produce simple devices, such as a prototype valve. Tough hydrogels based on interpenetrating networks of ionicially crosslinked alginate and covalently crosslinked polyacrylamide and poly(N-isopropylacrylamide) have been developed in a form suitable for extrusion printing with UV curing. Combined with UV-curable and extrudable rigid acrylated urethanes, the tough hydrogels can be 3D printed into composite materials or complex shapes with multiple different materials. An actuating valve was printed that operated thermally to open or close the flow path using 6 parallel hydrogel actuators. Textile processing methods such as knitting and weaving can be used to generate assemblies of actuating fibres. Low cost and high performance coiled fibres made from oriented polymers have been used for developing actuating textiles. Similarly, braiding methods have been developed to fabricate new forms of McKibben muscles that operate without any external apparatus, such as pumps, compressors or piping.

A soft and dexterous motor

NASA Astrophysics Data System (ADS)

Anderson, Iain A.; Tse, Tony Chun Hin; Inamura, Tokushu; O'Brien, Benjamin M.; McKay, Thomas; Gisby, Todd

2011-03-01

We present a soft, bearing-free artificial muscle motor that cannot only turn a shaft but also grip and reposition it through a flexible gear. The bearing-free operation provides a foundation for low complexity soft machines, with multiple degree-of-freedom actuation, that can act simultaneously as motors and manipulators. The mechanism also enables an artificial muscle controlled gear change. Future work will include self-sensing feedback for precision, multidegree-of-freedom operation.

Ion implanted dielectric elastomer circuits

NASA Astrophysics Data System (ADS)

O'Brien, Benjamin M.; Rosset, Samuel; Anderson, Iain A.; Shea, Herbert R.

2013-06-01

Starfish and octopuses control their infinite degree-of-freedom arms with panache—capabilities typical of nature where the distribution of reflex-like intelligence throughout soft muscular networks greatly outperforms anything hard, heavy, and man-made. Dielectric elastomer actuators show great promise for soft artificial muscle networks. One way to make them smart is with piezo-resistive Dielectric Elastomer Switches (DES) that can be combined with artificial muscles to create arbitrary digital logic circuits. Unfortunately there are currently no reliable materials or fabrication process. Thus devices typically fail within a few thousand cycles. As a first step in the search for better materials we present a preliminary exploration of piezo-resistors made with filtered cathodic vacuum arc metal ion implantation. DES were formed on polydimethylsiloxane silicone membranes out of ion implanted gold nano-clusters. We propose that there are four distinct regimes (high dose, above percolation, on percolation, low dose) in which gold ion implanted piezo-resistors can operate and present experimental results on implanted piezo-resistors switching high voltages as well as a simple artificial muscle inverter. While gold ion implanted DES are limited by high hysteresis and low sensitivity, they already show promise for a range of applications including hysteretic oscillators and soft generators. With improvements to implanter process control the promise of artificial muscle circuitry for soft smart actuator networks could become a reality.

Modeling and experiments on the drive characteristics of high-strength water hydraulic artificial muscles

NASA Astrophysics Data System (ADS)

Zhang, Zengmeng; Hou, Jiaoyi; Ning, Dayong; Gong, Xiaofeng; Gong, Yongjun

2017-05-01

Fluidic artificial muscles are popular in robotics and function as biomimetic actuators. Their pneumatic version has been widely investigated. A novel water hydraulic artificial muscle (WHAM) with high strength is developed in this study. WHAMs can be applied to underwater manipulators widely used in ocean development because of their environment-friendly characteristics, high force-to-weight ratio, and good bio-imitability. Therefore, the strength of WHAMs has been improved to fit the requirements of underwater environments and the work pressure of water hydraulic components. However, understanding the mechanical behaviors of WHAMs is necessary because WHAMs use work media and pressure control that are different from those used by pneumatic artificial muscles. This paper presents the static and dynamic characteristics of the WHAM system, including the water hydraulic pressure control circuit. A test system is designed and built to analyze the drive characteristics of the developed WHAM. The theoretical relationships among the amount of contraction, pressure, and output drawing force of the WHAM are tested and verified. A linearized transfer function is proposed, and the dynamic characteristics of the WHAM are investigated through simulation and inertia load experiments. Simulation results agree with the experimental results and show that the proposed model can be applied to the control of WHAM actuators.

Pneumatic artificial muscle actuators for compliant robotic manipulators

NASA Astrophysics Data System (ADS)

Robinson, Ryan Michael

Robotic systems are increasingly being utilized in applications that require interaction with humans. In order to enable safe physical human-robot interaction, light weight and compliant manipulation are desirable. These requirements are problematic for many conventional actuation systems, which are often heavy, and typically use high stiffness to achieve high performance, leading to large impact forces upon collision. However, pneumatic artificial muscles (PAMs) are actuators that can satisfy these safety requirements while offering power-to-weight ratios comparable to those of conventional actuators. PAMs are extremely lightweight actuators that produce force in response to pressurization. These muscles demonstrate natural compliance, but have a nonlinear force-contraction profile that complicates modeling and control. This body of research presents solutions to the challenges associated with the implementation of PAMs as actuators in robotic manipulators, particularly with regard to modeling, design, and control. An existing PAM force balance model was modified to incorporate elliptic end geometry and a hyper-elastic constitutive relationship, dramatically improving predictions of PAM behavior at high contraction. Utilizing this improved model, two proof-of-concept PAM-driven manipulators were designed and constructed; design features included parallel placement of actuators and a tendon-link joint design. Genetic algorithm search heuristics were employed to determine an optimal joint geometry; allowing a manipulator to achieve a desired torque profile while minimizing the required PAM pressure. Performance of the manipulators was evaluated in both simulation and experiment employing various linear and nonlinear control strategies. These included output feedback techniques, such as proportional-integral-derivative (PID) and fuzzy logic, a model-based control for computed torque, and more advanced controllers, such as sliding mode, adaptive sliding mode, and adaptive neural network control. Results demonstrated the benefits of an accurate model in model-based control, and the advantages of adaptive neural network control when a model is unavailable or variations in payload are expected. Lastly, a variable recruitment strategy was applied to a group of parallel muscles actuating a common joint. Increased manipulator efficiency was observed when fewer PAMs were activated, justifying the use of variable recruitment strategies. Overall, this research demonstrates the benefits of pneumatic artificial muscles as actuators in robotics applications. It demonstrates that PAM-based manipulators can be well-modeled and can achieve high tracking accuracy over a wide range of payloads and inputs while maintaining natural compliance.

Sensing and Tactile Artificial Muscles from Reactive Materials

PubMed Central

Conzuelo, Laura Valero; Arias-Pardilla, Joaquín; Cauich-Rodríguez, Juan V.; Smit, Mascha Afra; Otero, Toribio Fernández

2010-01-01

Films of conducting polymers can be oxidized and reduced in a reversible way. Any intermediate oxidation state determines an electrochemical equilibrium. Chemical or physical variables acting on the film may modify the equilibrium potential, so that the film acts as a sensor of the variable. The working potential of polypyrrole/DBSA (Dodecylbenzenesulfonic acid) films, oxidized or reduced under constant currents, changes as a function of the working conditions: electrolyte concentration, temperature or mechanical stress. During oxidation, the reactive material is a sensor of the ambient, the consumed electrical energy being the sensing magnitude. Devices based on any of the electrochemical properties of conducting polymers must act simultaneously as sensors of the working conditions. Artificial muscles, as electrochemical actuators constituted by reactive materials, respond to the ambient conditions during actuation. In this way, they can be used as actuators, sensing the surrounding conditions during actuation. Actuating and sensing signals are simultaneously included by the same two connecting wires. PMID:22319265

Inflatable actuators: an attempt for a common approach based on Treloar’s rubber elasticity theory

NASA Astrophysics Data System (ADS)

Tondu, Bertrand

2018-01-01

Inflatable actuators are defined as pressure hyperelastic vessels whose expansion is constrained for generating either movements in extension, or typical contractile movements of artificial muscles. By using Treloar’s theory of rubber elasticity, applied to thin-walled pressure vessels, we propose to determine in which conditions they can be considered as stable open-loop positioning actuators. Antagonism can be viewed as an extension of this open-loop stability principle applicable to artificial muscles as to extensible actuators. We especially show its relevance for multiple chambers pressurized cylinders and how Treloar’s theory can help to model their bending in a readable and relevant formal way. We also try to justify why we think that antagonism applied to extensible actuators can actually appear as the best way for designing miniaturized multiple degrees of freedom rubber made microactuators if, however, only a limited power is required.

Artificial muscles of dielectric elastomers attached to artificial tendons of functionalized carbon fibers

NASA Astrophysics Data System (ADS)

Ye, Zhihang; Faisal, Md. Shahnewaz Sabit; Asmatulu, Ramazan; Chen, Zheng

2014-03-01

Dielectric elastomers are soft actuation materials with promising applications in robotics and biomedical de- vices. In this paper, a bio-inspired artificial muscle actuator with artificial tendons is developed for robotic arm applications. The actuator uses dielectric elastomer as artificial muscle and functionalized carbon fibers as artificial tendons. A VHB 4910 tape is used as the dielectric elastomer and PDMS is used as the bonding material to mechanically connect the carbon fibers to the elastomer. Carbon fibers are highly popular for their high electrical conductivities, mechanical strengths, and bio-compatibilities. After the acid treatments for the functionalization of carbon fibers (500 nm - 10 μm), one end of carbon fibers is spread into the PDMS material, which provides enough bonding strength with other dielectric elastomers, while the other end is connected to a DC power supply. To characterize the actuation capability of the dielectric elastomer and electrical conductivity of carbon fibers, a diaphragm actuator is fabricated, where the carbon fibers are connected to the actuator. To test the mechanical bonding between PDMS and carbon fibers, specimens of PDMS bonded with carbon fibers are fabricated. Experiments have been conducted to verify the actuation capability of the dielectric elastomer and mechanical bonding of PDMS with carbon fibers. The energy efficiency of the dielectric elastomer increases as the load increases, which can reach above 50%. The mechanical bonding is strong enough for robotic arm applications.

Bio-inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn Muscles

PubMed Central

Kim, Shi Hyeong; Kwon, Cheong Hoon; Park, Karam; Mun, Tae Jin; Lepró, Xavier; Baughman, Ray H.; Spinks, Geoffrey M.; Kim, Seon Jeong

2016-01-01

Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg−1), which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture driven muscle. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space. PMID:26973137

Synthesis of an air-working trilayer artificial muscle using a conductive cassava starch biofilm (manihot esculenta, cranz) and polypyrrole (PPy)

NASA Astrophysics Data System (ADS)

Núñez D, Y. E.; Arrieta A, Á. A.; Segura B, J. A.; Bertel H, S. D.

2016-02-01

In this study, a methodology for obtaining a conductive cassava starch biofilm doped with lithium perchlorate (LiClO4) is shown, as well as the electrochemical technique for the synthesis of polypyrrole films, which are used for developing the trilayer artificial muscle PPy/Biopolymer/PPy designed to operate in air. Furthermore, results from the trilayer movement using chronoamperometric techniques are shown.

Dielectric elastomer actuators for facial expression

NASA Astrophysics Data System (ADS)

Wang, Yuzhe; Zhu, Jian

2016-04-01

Dielectric elastomer actuators have the advantage of mimicking the salient feature of life: movements in response to stimuli. In this paper we explore application of dielectric elastomer actuators to artificial muscles. These artificial muscles can mimic natural masseter to control jaw movements, which are key components in facial expressions especially during talking and singing activities. This paper investigates optimal design of the dielectric elastomer actuator. It is found that the actuator with embedded plastic fibers can avert electromechanical instability and can greatly improve its actuation. Two actuators are then installed in a robotic skull to drive jaw movements, mimicking the masseters in a human jaw. Experiments show that the maximum vertical displacement of the robotic jaw, driven by artificial muscles, is comparable to that of the natural human jaw during speech activities. Theoretical simulations are conducted to analyze the performance of the actuator, which is quantitatively consistent with the experimental observations.

A Novel Soft Pneumatic Artificial Muscle with High-Contraction Ratio.

PubMed

Han, Kwanghyun; Kim, Nam-Ho; Shin, Dongjun

2018-06-20

There is a growing interest in soft actuators for human-friendly robotic applications. However, it is very challenging for conventional soft actuators to achieve both a large working distance and high force. To address this problem, we present a high-contraction ratio pneumatic artificial muscle (HCRPAM), which has a novel actuation concept. The HCRPAM can contract substantially while generating a large force suitable for a wide range of robotic applications. Our proposed prototyping method allows for an easy and quick fabrication, considering various design variables. We derived a mathematical model using a virtual work principle, and validated the model experimentally. We conducted simulations for the design optimization using this model. Our experimental results show that the HCRPAM has a 183.3% larger contraction ratio and 37.1% higher force output than the conventional pneumatic artificial muscle (McKibben muscle). Furthermore, the actuator has a compatible position tracking performance of 1.0 Hz and relatively low hysteresis error of 4.8%. Finally, we discussed the controllable bending characteristics of the HCRPAM, which uses heterogeneous materials and has an asymmetrical structure to make it comfortable for a human to wear.

[Metabolic processes in rat skeletal muscle after a flight on the Kosmos-936 biosatellite].

PubMed

Nosova, E A; Veresotskaia, N A; Kolchina, E V; Kurkina, L M; Belitskaia, R A

1981-01-01

The study of skeletal muscles of rats flown on Cosmos-936 demonstrated different metabolic reactions in muscle fibers of different function and type to weightlessness and Earth gravity. The data obtained gave evidence that artificial gravity may considerably prevent metabolic changes in muscles developing in response to specific effects of weightlessness.

Utrophin Up-Regulation by an Artificial Transcription Factor in Transgenic Mice

PubMed Central

Mattei, Elisabetta; Corbi, Nicoletta; Di Certo, Maria Grazia; Strimpakos, Georgios; Severini, Cinzia; Onori, Annalisa; Desantis, Agata; Libri, Valentina; Buontempo, Serena; Floridi, Aristide; Fanciulli, Maurizio; Baban, Dilair; Davies, Kay E.; Passananti, Claudio

2007-01-01

Duchenne Muscular Dystrophy (DMD) is a severe muscle degenerative disease, due to absence of dystrophin. There is currently no effective treatment for DMD. Our aim is to up-regulate the expression level of the dystrophin related gene utrophin in DMD, complementing in this way the lack of dystrophin functions. To this end we designed and engineered several synthetic zinc finger based transcription factors. In particular, we have previously shown that the artificial three zinc finger protein named Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from the utrophin promoter “A”. Here we report on the characterization of Vp16-Jazz-transgenic mice that specifically over-express the utrophin gene at the muscular level. A Chromatin Immunoprecipitation assay (ChIP) demonstrated the effective access/binding of the Jazz protein to active chromatin in mouse muscle and Vp16-Jazz was shown to be able to up-regulate endogenous utrophin gene expression by immunohistochemistry, western blot analyses and real-time PCR. To our knowledge, this is the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger based transcription factor. The achievement of Vp16-Jazz transgenic mice validates the strategy of transcriptional targeting of endogenous genes and could represent an exclusive animal model for use in drug discovery and therapeutics. PMID:17712422

Electrically controllable twisted-coiled artificial muscle actuators using surface-modified polyester fibers

NASA Astrophysics Data System (ADS)

Park, Jungwoo; Yoo, Ji Wang; Seo, Hee Won; Lee, Youngkwan; Suhr, Jonghwan; Moon, Hyungpil; Koo, Ja Choon; Ryeol Choi, Hyouk; Hunt, Robert; Kim, Kwang Jin; Kim, Soo Hyun; Nam, Jae-Do

2017-03-01

As a new class of thermally activated actuators based on polymeric fibers, we investigated polyethylene terephthalate (PET) yarns for the development of a twisted-coiled polymer fiber actuator (TCA). The PET yarn TCA exhibited the maximum linear actuation up to 8.9% by external heating at above the glass transition temperature, 160 °C-180 °C. The payload of the actuator was successfully correlated with the preload and training-load conditions by an empirical equation. Furthermore, the PET-based TCA was electrically driven by Joule heating after the PET surface was metallization with silver. For the fast and precise control of PET yarn TCA, electroless silver plating was conducted to form electrical conductive layers on the PET fiber surface. The silver plated PET-based TCA was tested by Joule heating and the tensile actuation was increased up to 12.1% (6 V) due to the enhanced surface hardness and slippage of PET fibers. Overall, silver plating of the polymeric yarn provided a fast actuation speed and enhanced actuation performance of the TCA actuator by Joule heating, providing a great potential for being used in artificial muscle for biomimetic machines including robots, industrial actuators and powered exoskeletons.

Diet Affects Muscle Quality and Growth Traits of Grass Carp (Ctenopharyngodon idellus): A Comparison Between Grass and Artificial Feed

PubMed Central

Zhao, Honghao; Xia, Jianguo; Zhang, Xi; He, Xugang; Li, Li; Tang, Rong; Chi, Wei; Li, Dapeng

2018-01-01

Fish muscle, the main edible parts with high protein level and low fat level, is consumed worldwide. Diet contributes greatly to fish growth performance and muscle quality. In order to elucidate the correlation between diet and muscle quality, the same batch of juvenile grass carp (Ctenopharyngodon idellus) were divided into two groups and fed with either grass (Lolium perenne, Euphrasia pectinata and Sorghum sudanense) or artificial feed, respectively. However, the different two diets didn't result in significant differences in all the detected water quality parameters (e.g., Tm, pH, DO, NH3/NH4+-N, NO3--N, NO2-, TN, TP, and TOC) between the two experimental groups. After a 4-month culture period, various indexes and expression of myogenic regulatory factor (MRFs) and their related genes were tested. The weight gain of the fish fed with artificial feed (AFG) was nearly 40% higher than the fish fed with grass (GFG). Significantly higher alkaline phosphatase, total cholestrol, high density cholestrol and total protein were detected in GFG as compared to AFG. GFG also showed increased hardness, resilience and shear force in texture profile analysis, with significantly bigger and compact muscle fibers in histologic slices. The fat accumulation was most serious in the abdomen muscle of AFG. Additionally, the expression levels of MyoG, MyoD, IGF-1, and MSTNs were higher, whereas Myf-5, MRF4, and IGF-2 were lower in most positional muscles of GFG as compared to AFG. Overall, these results suggested that feeding grass could promote muscle growth and development by stimulating muscle fiber hypertrophy, as well as significantly enhance the expression of CoL1As. Feeding C. idellus with grass could also improve flesh quality by improving muscle characteristics, enhancing the production of collagen, meanthile, reducing fat accumulation and moisture in muscle, but at the cost of a slower growth. PMID:29632496

Bio-Based Artificial Nacre with Excellent Mechanical and Barrier Properties Realized by a Facile In Situ Reduction and Cross-Linking Reaction.

PubMed

Shahzadi, Kiran; Mohsin, Imran; Wu, Lin; Ge, Xuesong; Jiang, Yijun; Li, Hui; Mu, Xindong

2017-01-24

Demands for high strength integrated materials have substantially increased across various kinds of industries. Inspired by the relationship of excellent integration of mechanical properties and hierarchical nano/microscale structure of the natural nacre, a simple and facile method to fabricate high strength integrated artificial nacre based on sodium carboxymethylcellulose (CMC) and borate cross-linked graphene oxide (GO) sheets has been developed. The tensile strength and toughness of cellulose-based hybrid material reached 480.5 ± 13.1 MPa and 11.8 ± 0.4 MJm -3 by a facile in situ reduction and cross-linking reaction between CMC and GO (0.7%), which are 3.55 and 6.55 times that of natural nacre. This hybrid film exhibits better thermal stability and flame retardancy. More interestingly, the hybrid material showed good water stability compared to that in the original water-soluble CMC. This type of hybrid has great potential applications in aerospace, artificial muscle, and tissue engineering.

New horizons for orthotic and prosthetic technology: artificial muscle for ambulation

NASA Astrophysics Data System (ADS)

Herr, Hugh M.; Kornbluh, Roy D.

2004-07-01

The rehabilitation community is at the threshold of a new age in which orthotic and prosthetic devices will no longer be separate, lifeless mechanisms, but intimate extensions of the human body-structurally, neurologically, and dynamically. In this paper we discuss scientific and technological advances that promise to accelerate the merging of body and machine, including the development of actuator technologies that behave like muscle and control methodologies that exploit principles of biological movement. We present a state-of-the-art device for leg rehabilitation: a powered ankle-foot orthosis for stroke, cerebral palsy, or multiple sclerosis patients. The device employs a forcecontrollable actuator and a biomimetic control scheme that automatically modulates ankle impedance and motive torque to satisfy patient-specific gait requirements. Although the device has some clinical benefits, problems still remain. The force-controllable actuator comprises an electric motor and a mechanical transmission, resulting in a heavy, bulky, and noisy mechanism. As a resolution of this difficulty, we argue that electroactive polymer-based artificial muscle technologies may offer considerable advantages to the physically challenged, allowing for joint impedance and motive force controllability, noise-free operation, and anthropomorphic device morphologies.

Multi-functional dielectric elastomer artificial muscles for soft and smart machines

NASA Astrophysics Data System (ADS)

Anderson, Iain A.; Gisby, Todd A.; McKay, Thomas G.; O'Brien, Benjamin M.; Calius, Emilio P.

2012-08-01

Dielectric elastomer (DE) actuators are popularly referred to as artificial muscles because their impressive actuation strain and speed, low density, compliant nature, and silent operation capture many of the desirable physical properties of muscle. Unlike conventional robots and machines, whose mechanisms and drive systems rapidly become very complex as the number of degrees of freedom increases, groups of DE artificial muscles have the potential to generate rich motions combining many translational and rotational degrees of freedom. These artificial muscle systems can mimic the agonist-antagonist approach found in nature, so that active expansion of one artificial muscle is taken up by passive contraction in the other. They can also vary their stiffness. In addition, they have the ability to produce electricity from movement. But departing from the high stiffness paradigm of electromagnetic motors and gearboxes leads to new control challenges, and for soft machines to be truly dexterous like their biological analogues, they need precise control. Humans control their limbs using sensory feedback from strain sensitive cells embedded in muscle. In DE actuators, deformation is inextricably linked to changes in electrical parameters that include capacitance and resistance, so the state of strain can be inferred by sensing these changes, enabling the closed loop control that is critical for a soft machine. But the increased information processing required for a soft machine can impose a substantial burden on a central controller. The natural solution is to distribute control within the mechanism itself. The octopus arm is an example of a soft actuator with a virtually infinite number of degrees of freedom (DOF). The arm utilizes neural ganglia to process sensory data at the local "arm" level and perform complex tasks. Recent advances in soft electronics such as the piezoresistive dielectric elastomer switch (DES) have the potential to be fully integrated with actuators and sensors. With the DE switch, we can produce logic gates, oscillators, and a memory element, the building blocks for a soft computer, thus bringing us closer to emulating smart living structures like the octopus arm. The goal of future research is to develop fully soft machines that exploit smart actuation networks to gain capabilities formerly reserved to nature, and open new vistas in mechanical engineering.

Comparison of contractile and extensile pneumatic artificial muscles

NASA Astrophysics Data System (ADS)

Pillsbury, Thomas E.; Wereley, Norman M.; Guan, Qinghua

2017-09-01

Pneumatic artificial muscles (PAMs) are used in robotic and prosthetic applications due to their high power to weight ratio, controllable compliance, and simple design. Contractile PAMs are typically used in traditional hard robotics in place of heavy electric motors. As the field of soft robotics grows, extensile PAMs are beginning to have increased usage. This work experimentally tests, models, and compares contractile and extensile PAMs to demonstrate the advantages and disadvantages of each type of PAM and applications for which they are best suited.

Ionic polymer-metal composite enabled robotic manta ray

NASA Astrophysics Data System (ADS)

Chen, Zheng; Um, Tae I.; Bart-Smith, Hilary

2011-04-01

The manta ray, Manta birostris, demonstrates excellent swimming capabilities; generating highly efficient thrust via flapping of dorsally flattened pectoral fins. In this paper, we present an underwater robot that mimics the swimming behavior of the manta ray. An assembly-based fabrication method is developed to create the artificial pectoral fins, which are capable of generating oscillatory with a large twisting angle between leading and trailing edges. Ionic polymer-metal composite (IPMC) actuators are used as artificial muscles in the fin. Each fin consists of four IPMC beams bonded with a compliant poly(dimethylsiloxane) (PDMS) membrane. By controlling each individual IPMC strips, we are able to generate complex flapping motions. The fin is characterized in terms of tip deflection, tip blocking force, twist angle, and power consumption. Based on the characteristics of the artificial pectoral fin, a small size and free-swimming robotic manta ray is developed. The robot consists of two artificial pectoral fins, a rigid body, and an on-board control unit with a lithium ion rechargeable battery. Experimental results show that the robot swam at a speed of up to 0.055 body length per second (BL/sec).

EDITORIAL: Artificial Muscles: Selected papers from the 5th World Congress on Biomimetics, Artificial Muscles and Nano-Bio (Osaka, Japan, 25-27 November 2009) Artificial Muscles: Selected papers from the 5th World Congress on Biomimetics, Artificial Muscles and Nano-Bio (Osaka, Japan, 25-27 November 2009)

NASA Astrophysics Data System (ADS)

Shahinpoor, Mohsen

2011-12-01

The 5th World Congress on Biomimetics, Artificial Muscles and Nano-Bio and the 4th International Conference on Artificial Muscles were held in Osaka, Japan, 23-27 November 2009. This special section of Smart Materials and Structures is devoted to a selected number of research papers presented at this international conference and congress. Of the 76 or so papers presented at the conference, only 10 papers were finally selected, reviewed and accepted for this special section, following the regular reviewing procedures of the journal. This special section is focused on polymeric artificial muscles, electroactive polymers, multifunctional nanocomposites and their applications. In particular, an electromechanical model for self-sensing ionic polymer-metal composite actuating devices with patterned surface electrodes is presented which discusses the concept of creating self-sensing ionic polymer-metal composite (IPMC) actuating devices with patterned surface electrodes where actuator and sensor elements are separated by a grounded shielding electrode. Eventually, an electromechanical model of the device is also proposed and validated. Following that, there is broad coverage of polytetrahydrofurane-polyethylene oxide-PEDOT conducting interpenetrating polymer networks (IPNs) for high speed actuators. The conducting polymer (poly(3,4-ethylenedioxythiophene)) is incorporated within the IPNs, which are synthesized from polyethylene oxide (PEO)/polytetrahydrofurane (PTHF) networks. PEO/PTHF IPNs are prepared using poly(ethylene glycol) methacrylate and dimethacrylate and hydroxythelechelic PTHF as starting materials. The conducting IPN actuators are prepared by oxidative polymerization of 3,4-ethylenedioxithiophene (EDOT) using FeCl3 as an oxidizing agent within the PEO/PTHF IPN host matrix. Subsequently, giant and reversible magnetorheology of carrageenan/iron oxide magnetic gels are discussed and the effect of magnetic fields on the viscoelastic properties, magnetorheological effect of carrageenan gel containing iron oxide particles are investigated using dynamic viscoelastic measurements under magnetic fields. Furthermore, the relationship between the magnetorheology and the elasticity of magnetic gel is discussed. This special section then covers the characteristics of ionic polymer-metal composite with chemically-doped TiO2 particles to improve the bending performance of ionic polymer-metal composite (IPMC) actuators. This study is mainly focused on the characterization of the physical, electrochemical, and electromechanical properties of TiO2-doped ionic polymer membranes, and IPMCs prepared by the sol-gel method, which results in a uniform distribution of the particles inside the polymer membrane. It was determined that the lifetime of IPMC is strongly dependent on the level of water uptake. This paper is then followed by a presentation on training and shape retention in conducting polymer artificial muscles. Electrochemomechanical deformation (ECMD) of the conducting polymer, polyaniline film, is studied to investigate the behavior of actuation under tensile loads. The ECMD is induced by strains due to insertion of ionic species (cyclic strain) and a creep due to applied loads during the redox cycle. The cyclic strain is enhanced by the experience of high tensile loads, indicating a training effect. The training effect is explained by the enhanced electrochemical activity of the film. The special section then presents a paper on the current status and future prospects of power generators using dielectric elastomers. Electroactive polymer artificial muscle (EPAM), known as 'dielectric elastomer', appears to offer unique capabilities as an actuator and electrical power generator. However, the power output levels of such generators are small and the efficiencies are rather high. For example, electrical energy conversion efficiency of over 70% has been achieved. The ability of EPAM to produce hydrogen fuel for energy storage was also demonstrated. Because the energy conversion principle of EPAM is capacitive in nature, the performance is largely size-independent. Formation of motile assembly of microtubules driven by kinesins is presented next. Microtubule (MT) and kinesin are rail and motor proteins that are involved in various moving events of eukaryotic cells in natural systems. In vitro, the sliding motion of microtubules (rail) can be reproduced on a kinesin (motor protein)-coated surface coupled with adenosine triphosphate (ATP) hydrolysis, which is called a 'motility assay'. Based on this technique, a method is reported for forming MT assemblies by an active self-assembly (AcSA) process, in which MTs are crosslinked during a sliding motion on a kinesin-coated surface. Streptavidin (ST) is employed as glue to crosslink biotin-labeled MTs. This discussion is then followed by a paper on the performances of fast-moving low-voltage electromechanical actuators based on single-walled carbon nanotubes and ionic liquids. Here the mechanical and electrical properties of the polymer-free single-walled carbon nanotube (SWNT) sheets containing different contents of ionic liquids (ILs) are reported. The polymer-free SWNT sheets are prepared with the knowledge that millimeter-long 'super growth' carbon nanotubes (SG-SWNTs), produced by a water-assisted modified CVD method, associate together tightly with ILs. The molecular mechanism of electroactive polymer actuators is then discussed in the next paper. Movement of ionic electroactive polymer actuators utilizes their anisotropic volume change, which is induced by the applied voltage. The mechanism of the volume change is, however, not well understood, especially at the molecular level. The current understanding of the mechanism of the volume change at the molecular level is reviewed, focusing on the actuators made with carbon materials. Then, the pressure generated in the actuators in response to the applied voltage based on the results of the Monte Carlo simulation is discussed. It is shown that the mechanism of the actuators can be analyzed at the molecular level in terms of the balance between the electrostatic and volume exclusion interactions that act among the electrode materials and the electrolyte ions. The special section then presents a master curve for analyzing the electrochemical aging and memory effects of poly(3,4-ethylenedioxythiophene). The memory effect of conducting polymers in an electrochemical environment is investigated. This memory effect is related to the electromechanical responses of the conducting polymer. Poly(3,4-ethylenedioxythiophene) is chosen because of its interesting properties—mainly its chemical and electrochemical stabilities. By means of cyclic voltammetry, the influence of the waiting time tw at a holding potential Ew in relation to the conformational relaxation process occurring in the conducting polymer is analyzed. The effect of electrochemical aging on the electrical properties is also explained from the viewpoint of the rearrangement of polymer chains. This completes a brief report on the content of the special section on artificial muscles. I would like to thank the contributing authors of this collection of papers on artificial muscles for their outstanding and unique contributions. I am also indebted to all of the reviewers, editors and editorial staff who handled the reviews of all the papers for their time and effort. I would like to express my sincere thanks and appreciation to Professor E Garcia, Editor-in-Chief, for his encouragement and support, and for providing the opportunity to publish this special section of Smart Materials and Structures. I am also grateful to the IOP Publishing team for their support. In particular, I am greatly indebted to publisher Natasha Leeper, for her help and excellent management in the preparation of this special section on artificial muscles.

An artificial muscle actuator for biomimetic underwater propulsors.

PubMed

Yim, Woosoon; Lee, Joonsoo; Kim, Kwang J

2007-06-01

In this paper, we introduce the analytical framework of the modeling dynamic characteristics of a soft artificial muscle actuator for aquatic propulsor applications. The artificial muscle used for this underwater application is an ionic polymer-metal composite (IPMC) which can generate bending motion in aquatic environments. The inputs of the model are the voltages applied to multiple IPMCs, and the output can be either the shape of the actuators or the thrust force generated from the interaction between dynamic actuator motions and surrounding water. In order to determine the relationship between the input voltages and the bending moments, the simplified RC model is used, and the mechanical beam theory is used for the bending motion of IPMC actuators. Also, the hydrodynamic forces exerted on an actuator as it moves relative to the surrounding medium or water are added to the equations of motion to study the effect of actuator bending on the thrust force generation. The proposed method can be used for modeling the general bending type artificial muscle actuator in a single or segmented form operating in the water. The segmented design has more flexibility in controlling the shape of the actuator when compared with the single form, especially in generating undulatory waves. Considering an inherent nature of large deformations in the IPMC actuator, a large deflection beam model has been developed and integrated with the electrical RC model and hydrodynamic forces to develop the state space model of the actuator system. The model was validated against existing experimental data.

Technical Rebuilding of Movement Function Using Functional Electrical Stimulation

NASA Astrophysics Data System (ADS)

Gföhler, Margit

To rebuild lost movement functions, neuroprostheses based on functional electrical stimulation (FES) artificially activate skeletal muscles in corresponding sequences, using both residual body functions and artificial signals for control. Besides the functional gain, FES training also brings physiological and psychological benefits for spinal cord-injured subjects. In this chapter, current stimulation technology and the main components of FES-based neuroprostheses including enhanced control systems are presented. Technology and application of FES cycling and rowing, both approaches that enable spinal cord-injured subjects to participate in mainstream activities and improve their health and fitness by exercising like able-bodied subjects, are discussed in detail, and an overview of neuroprostheses that aim at restoring movement functions for daily life as walking or grasping is given.

Development and characterization of self-healing carbon fabric/ionomer composite through stitched polymeric artificial muscle

NASA Astrophysics Data System (ADS)

Gabriel, Mark Joseph

Typical cracks in composite materials are hard to detect, because they may be very small or occur inside the material. This study investigates the development and characterization of carbon fiber and an ionomer, self-healing, laminate composite, enhanced with stitched artificial muscle elements. Although the carbon fiber is used as a structural reinforcement, the carbon fiber can also act as a resistive heating element in order to activate the healing elements in a Close-Then-Heal (CTH) approach. However in this study, hot air in an oven was used to activate the, SurlynRTM 8940, self-healing matrix. Artificial muscle was prepared from commercial fishing line to stitch reinforce the carbon laminate composite in the Z plane. Holes were drilled into the final composite and the muscle was stitched into the composite for active reinforcement. Differential scanning calorimetry was used to characterize the matrix and fishing line properties. The resulting smart composite was subjected to low velocity impact tests and consequential damage before healing in an oven, followed by three point bending flexure tests. Cracks in the carbon fiber reinforcement formed more easily than expected after impact because the holes were drilled to facilitate the muscle stitching. The matrix material could heal, but the reinforcement carbon could not. Several equipment issues and failures limited the amount of samples that could be created to continue testing with new parameters.

Establishing the framework to support bioartificial heart fabrication using fibrin-based three-dimensional artificial heart muscle.

PubMed

Hogan, Matthew; Mohamed, Mohamed; Tao, Ze-Wei; Gutierrez, Laura; Birla, Ravi

2015-02-01

Only 3000 heart transplants are performed in the USA every year, leaving some 30 000-70 000 Americans without proper care. Current treatment modalities for heart failure have saved many lives yet still do not correct the underlying problems of congestive heart failure. Tissue engineering represents a potential field of study wherein a combination of cells, scaffolds, and/or bioreactors can be utilized to create constructs to mimic, replace, and/or repair defective tissue. The focus of this study was to generate a bioartificial heart (BAH) model using artificial heart muscle (AHM), composed of fibrin gel and neonatal rat cardiac myocytes, and a decellularized scaffold, formed by subjecting an adult rat heart to a series of decellularization solutions. By suturing the AHM around the outside of the decellularized heart and culturing while suspended in media, we were able to retain functional cardiac cells on the scaffold as evinced by visible contractility. Observed contractility rate was correlated with biopotential measurements to confirm essential functionality of cardiac constructs. Cross-sections of the BAH show successful decellularization of the scaffold and contiguous cell-rich AHM around the perimeter of the heart. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Artificial muscles' enrichment text: Chemical Literacy Profile of pre-service teachers

NASA Astrophysics Data System (ADS)

Hernani, Ulum, Luthfi Lulul; Mudzakir, Ahmad

2017-08-01

This research aims to determine the profile of chemical literacy abilities of pre-service teachers based on scientific attitudes and scientific competencies in PISA 2015 through individualized learning by using an artificial muscle context based-enrichment book. This research uses descriptive method, involving 20 of the 90 randomly selected population. This research uses a multiple-choice questions instrument. The result of this research are : 1) in the attitude aspects of interest in science and technology, valuing scientific approaches to inquiry, and environmental awareness, the results obtained respectively for 90%, 80%, and 30%. 2) for scientific competence of apply appropriate scientific knowledge, identify models and representations, make appropriate predictions, and explain the potential implications of scientific knowledge for society, the results obtained respectively for 30%, 50%, 60%, and 55%. 3) For scientific competence of identify the question explored in a given scientific study and distinguish questions that could be investigated scientifically, the results obtained respectively for 30 % and 50%. 4) For scientific competence of transform data from one representation to another and draw appropriate conclusions, the results obtained respectively for 60% and 45%. Based on the results, which need to be developed in pre-service chemistry teachers are environmental awareness, apply appropriate scientific knowledge, identify the question explored in a given scientific study, and draw appropriate conclusions.

A review of football injuries on third and fourth generation artificial turfs compared with natural turf.

PubMed

Williams, Sean; Hume, Patria A; Kara, Stephen

2011-11-01

Football codes (rugby union, soccer, American football) train and play matches on natural and artificial turfs. A review of injuries on different turfs was needed to inform practitioners and sporting bodies on turf-related injury mechanisms and risk factors. Therefore, the aim of this review was to compare the incidence, nature and mechanisms of injuries sustained on newer generation artificial turfs and natural turfs. Electronic databases were searched using the keywords 'artificial turf', 'natural turf', 'grass' and 'inj*'. Delimitation of 120 articles sourced to those addressing injuries in football codes and those using third and fourth generation artificial turfs or natural turfs resulted in 11 experimental papers. These 11 papers provided 20 cohorts that could be assessed using magnitude-based inferences for injury incidence rate ratio calculations pertaining to differences between surfaces. Analysis showed that 16 of the 20 cohorts showed trivial effects for overall incidence rate ratios between surfaces. There was increased risk of ankle injury playing on artificial turf in eight cohorts, with incidence rate ratios from 0.7 to 5.2. Evidence concerning risk of knee injuries on the two surfaces was inconsistent, with incidence rate ratios from 0.4 to 2.8. Two cohorts showed beneficial inferences over the 90% likelihood value for effects of artificial surface on muscle injuries for soccer players; however, there were also two harmful, four unclear and five trivial inferences across the three football codes. Inferences relating to injury severity were inconsistent, with the exception that artificial turf was very likely to have harmful effects for minor injuries in rugby union training and severe injuries in young female soccer players. No clear differences between surfaces were evident in relation to training versus match injuries. Potential mechanisms for differing injury patterns on artificial turf compared with natural turf include increased peak torque and rotational stiffness properties of shoe-surface interfaces, decreased impact attenuation properties of surfaces, differing foot loading patterns and detrimental physiological responses. Changing between surfaces may be a precursor for injury in soccer. In conclusion, studies have provided strong evidence for comparable rates of injury between new generation artificial turfs and natural turfs. An exception is the likely increased risk of ankle injury on third and fourth generation artificial turfs. Therefore, ankle injury prevention strategies must be a priority for athletes who play on artificial turf regularly. Clarification of effects of artificial surfaces on muscle and knee injuries are required given inconsistencies in incidence rate ratios depending on the football code, athlete, gender or match versus training.

The artificial gene Jazz, a transcriptional regulator of utrophin, corrects the dystrophic pathology in mdx mice.

PubMed

Di Certo, Maria Grazia; Corbi, Nicoletta; Strimpakos, Georgios; Onori, Annalisa; Luvisetto, Siro; Severini, Cinzia; Guglielmotti, Angelo; Batassa, Enrico Maria; Pisani, Cinzia; Floridi, Aristide; Benassi, Barbara; Fanciulli, Maurizio; Magrelli, Armando; Mattei, Elisabetta; Passananti, Claudio

2010-03-01

The absence of the cytoskeletal protein dystrophin results in Duchenne muscular dystrophy (DMD). The utrophin protein is the best candidate for dystrophin replacement in DMD patients. To obtain therapeutic levels of utrophin expression in dystrophic muscle, we developed an alternative strategy based on the use of artificial zinc finger transcription factors (ZF ATFs). The ZF ATF 'Jazz' was recently engineered and tested in vivo by generating a transgenic mouse specifically expressing Jazz at the muscular level. To validate the ZF ATF technology for DMD treatment we generated a second mouse model by crossing Jazz-transgenic mice with dystrophin-deficient mdx mice. Here, we show that the artificial Jazz protein restores sarcolemmal integrity and prevents the development of the dystrophic disease in mdx mice. This exclusive animal model establishes the notion that utrophin-based therapy for DMD can be efficiently developed using ZF ATF technology and candidates Jazz as a novel therapeutic molecule for DMD therapy.

Computer-aided mechanogenesis of skeletal muscle organs from single cells in vitro

NASA Technical Reports Server (NTRS)

Vanderburgh, Herman H.; Swasdison, Somporn; Karlisch, Patricia

1991-01-01

Complex mechanical forces generated in the growing embryo play an important role in organogenesis. Computerized application of similar forces to differentiating skeletal muscle myoblasts in vitro generate three dimensional artificial muscle organs. These organs contain parallel networks of long unbranched myofibers organized into fascicle-like structures. Tendon development is initiated and the muscles are capable of performing directed, functional work. Kinetically engineered organs provide a new method for studying the growth and development of normal and diseased skeletal muscle.

Computer aided mechanogenesis of skeletal muscle organs from single cells in vitro

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.; Swasdison, Somporn; Karlisch, Patricia

1990-01-01

Complex mechanical forces generated in the growing embryo play an important role in organogenesis. Computerized application of similar forces to differentiating skeletal muscle myoblasts in vitro generate three dimensional artificial muscle organs. These organs contain parallel networks of long unbranched myofibers organized into fascicle-like structures. Tendon development is initiated and the muscles are capable of performing directed, functional work. Kinetically engineered organs provide a new method for studying the growth and development of normal and diseased skeletal muscle.

[Progress in porky genes and transcriptome and discussion of relative issues].

PubMed

Zhu, Meng-Jin; Liu, Bang; Li, Kui

2005-01-01

To date, research on molecular base of porky molecular development was mainly involved in muscle growth and meat quality. Some functional genes including Hal gene and RN gene and some QTLs controlling or associated with porky growth and quality were detected through candidate gene approach and genome-wide scanning. Genic transcriptome pertinent to porcine muscle and adipose also came into study. At the same time, these researches have befallen some shortcomings to some extent. Research from molecular quantitative genetics showed shortcomings that single gene was devilishly emphasized and co-expression pattern of multi-genes was ignored. Research applying transcriptome analysis tool also met two of limitations, one was the singleness of type of molecular experimental techniques, and another was that genes of muscle and adipose were artificially divided into unattached two parts. Thus, porky genes were explored by parallel genetics based on systemic views and techniques to specially reveal the interactional mechanism of porky genes respectively controlling muscle and adipose, which would be important issues of genes and genome researches on porky development in the near future.

Theory of the tensile actuation of fiber reinforced coiled muscles

NASA Astrophysics Data System (ADS)

Lamuta, C.; Messelot, S.; Tawfick, S.

2018-05-01

There is a strong need for compact artificial muscles capable of applying large contractile strokes and lift heavy weights. Coiled fibers recently emerged as attractive candidates for these purposes, owing to their simple construction and the possibility of their thermal, electrical and chemical actuation. An intuitive theoretical understanding of the mechanics of actuation of these muscles is essential for the enhancement of their performance and can pave the way for the development of new applications and technologies. In this paper, a complete theoretical model for the tensile actuation of fiber reinforced artificial muscles is presented and experimentally validated. The model demonstrates that all muscles made from the same material have a universal behavior, which can be described by a single master curve. It enables the systematic design and understanding of coiled muscles for specific performance owing to a comprehensive mathematical correlation among the geometry, materials properties, and actuation. Carbon fibers (CF)/polydimethylsiloxane coiled muscles are demonstrated as simple to fabricate yet powerful muscles owing to the availability of high strength CF. In addition to showing excellent agreement with the theoretical models, they can be actuated by joule heating or chemical swelling, lift up to 12 600 times their own weight, support up to 60 MPa of mechanical stress, provide tensile strokes higher than 25%, and a specific work up to 758 J kg‑1, the latter is more than 18 times higher than that of natural muscles.

Design and characterization of a hyperelastic tubular soft composite.

PubMed

Shaheen, Robert; Doumit, Marc; Helal, Alexander

2017-11-01

Research in the field of human mobility assistive devices, aiming to reduce the metabolic cost of daily activities, is seeing the benefits of the exclusive use of passive actuators to store and release energy during the gait cycle. Current devices commonly employ either mechanical springs or Pneumatic Artificial Muscles as the primary method of passive actuation. The Pneumatic Artificial Muscle has proven to be a superior actuation choice for these devices, when compared to its alternatives. However, challenges regarding muscle pressure loss and limited elongation potential have been identified. This paper presents a hyperelastic tubular Soft Composite that replicates the distinctive mechanical behaviour of the Pneumatic Artificial Muscle without the need for internal pressurization. The proposed Soft Composite solution is achieved by impregnating a prefabricated polyethylene terephthalate braided sleeve, held at a high initial fibre angle, with a silicone prepolymer. A comprehensive experimental evaluation is achieved on numerous prototypes for a variety of customizable design parameters including: the initial fibre angle, the silicone stiffness, and the braided sleeve style. This research has successfully developed, tested, and validated a novel Soft Composite that can achieve the desired nonlinear stiffness and elongation potential for optimal use as passive actuation in human mobility assistive devices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling of dielectric elastomer oscillators for soft biomimetic applications.

PubMed

Henke, E-F M; Wilson, Katherine E; Anderson, I A

2018-06-26

Biomimetic, entirely soft robots with animal-like behavior and integrated artificial nervous systems will open up totally new perspectives and applications. However, until now, most presented studies on soft robots were limited to only partly soft designs, since all solutions at least needed conventional, stiff electronics to sense, process signals and activate actuators. We present a novel approach for a set up and the experimental validation of an artificial pace maker that is able to drive basic robotic structures and act as artificial central pattern generator. The structure is based on multi-functional dielectric elastomers (DEs). DE actuators, DE switches and DE resistors are combined to create complex DE oscillators (DEOs). Supplied with only one external DC voltage, the DEO autonomously generates oscillating signals that can be used to clock a robotic structure, control the cyclic motion of artificial muscles in bionic robots or make a whole robotic structure move. We present the basic functionality, derive a mathematical model for predicting the generated signal waveform and verify the model experimentally.

Use of sEMG in identification of low level muscle activities: features based on ICA and fractal dimension.

PubMed

Naik, Ganesh R; Kumar, Dinesh K; Arjunan, Sridhar

2009-01-01

This paper has experimentally verified and compared features of sEMG (Surface Electromyogram) such as ICA (Independent Component Analysis) and Fractal Dimension (FD) for identification of low level forearm muscle activities. The fractal dimension was used as a feature as reported in the literature. The normalized feature values were used as training and testing vectors for an Artificial neural network (ANN), in order to reduce inter-experimental variations. The identification accuracy using FD of four channels sEMG was 58%, and increased to 96% when the signals are separated to their independent components using ICA.

Muscle synergies in neuroscience and robotics: from input-space to task-space perspectives.

PubMed

Alessandro, Cristiano; Delis, Ioannis; Nori, Francesco; Panzeri, Stefano; Berret, Bastien

2013-01-01

In this paper we review the works related to muscle synergies that have been carried-out in neuroscience and control engineering. In particular, we refer to the hypothesis that the central nervous system (CNS) generates desired muscle contractions by combining a small number of predefined modules, called muscle synergies. We provide an overview of the methods that have been employed to test the validity of this scheme, and we show how the concept of muscle synergy has been generalized for the control of artificial agents. The comparison between these two lines of research, in particular their different goals and approaches, is instrumental to explain the computational implications of the hypothesized modular organization. Moreover, it clarifies the importance of assessing the functional role of muscle synergies: although these basic modules are defined at the level of muscle activations (input-space), they should result in the effective accomplishment of the desired task. This requirement is not always explicitly considered in experimental neuroscience, as muscle synergies are often estimated solely by analyzing recorded muscle activities. We suggest that synergy extraction methods should explicitly take into account task execution variables, thus moving from a perspective purely based on input-space to one grounded on task-space as well.

Could anterior papillary muscle partial necrosis explain early mitral valve repair failure?

PubMed

Pozzi, Matteo; Generali, Tommaso; Henaine, Roland; Mitchell, Julia; Lemaire, Anais; Chiari, Pascal; Fran, Jean; Obadia, Jean François

2014-09-01

Standardized techniques of mitral valve repair (MVR) have recently witnessed the introduction of a 'respect rather than resect' concept, the strategy of which involves the use of artificial chordae. MVR displays several advantages over mitral valve replacement in degenerative mitral regurgitation (MR), but the risk of reoperation for MVR failure must be taken into account. Different mechanisms could be advocated as the leading cause of MVR failure; procedure-related mechanisms are usually involved in early MVR failure, while valve-related mechanisms are common in late failure. Here, the case is reported of an early failure of MVR using artificial chordae that could be explained by an unusual procedure-related mechanism, namely anterior papillary muscle necrosis. MVR failure is a well-known complication after surgical repair of degenerative MR, but anterior papillary muscle partial necrosis might also be considered a possible mechanism of procedure-related MVR failure, especially when considering the increasing use of artificial chordae. Owing to the encouraging results obtained, mitral valve re-repair might be considered a viable solution, but must be selected after only a meticulous evaluation of the underlying mechanism of MVR failure.

New control strategies for neuroprosthetic systems.

PubMed

Crago, P E; Lan, N; Veltink, P H; Abbas, J J; Kantor, C

1996-04-01

The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to accomplish these tasks include feedforward (open-loop), feedback, and adaptive control. Feedforward control requires a great deal of information about the biomechanical behavior of the limb. For the upper extremity, an artificial motor program was developed to provide such movement program input to a neuroprosthesis. In lower extremity control, one group achieved their best results by attempting to meet naturally perceived gait objectives rather than to follow an exact joint angle trajectory. Adaptive feedforward control, as implemented in the cycle-to-cycle controller, gave good compensation for the gradual decrease in performance observed with open-loop control. A neural network controller was able to control its system to customize stimulation parameters in order to generate a desired output trajectory in a given individual and to maintain tracking performance in the presence of muscle fatigue. The authors believe that practical FNS control systems must exhibit many of these features of neurophysiological systems.

Examination of mitral regurgitation with a goat heart model for the development of intelligent artificial papillary muscle.

PubMed

Shiraishi, Y; Yambe, T; Yoshizawa, M; Hashimoto, H; Yamada, A; Miura, H; Hashem, M; Kitano, T; Shiga, T; Homma, D

2012-01-01

Annuloplasty for functional mitral or tricuspid regurgitation has been made for surgical restoration of valvular diseases. However, these major techniques may sometimes be ineffective because of chamber dilation and valve tethering. We have been developing a sophisticated intelligent artificial papillary muscle (PM) by using an anisotropic shape memory alloy fiber for an alternative surgical reconstruction of the continuity of the mitral structural apparatus and the left ventricular myocardium. This study exhibited the mitral regurgitation with regard to the reduction in the PM tension quantitatively with an originally developed ventricular simulator using isolated goat hearts for the sophisticated artificial PM. Aortic and mitral valves with left ventricular free wall portions of isolated goat hearts (n=9) were secured on the elastic plastic membrane and statically pressurized, which led to valvular leaflet-papillary muscle positional change and central mitral regurgitation. PMs were connected to the load cell, and the relationship between the tension of regurgitation and PM tension were measured. Then we connected the left ventricular specimen model to our hydraulic ventricular simulator and achieved hemodynamic simulation with the controlled tension of PMs.

Propulsion System with Pneumatic Artificial Muscles for Powering Ankle-Foot Orthosis

NASA Astrophysics Data System (ADS)

Veneva, Ivanka; Vanderborght, Bram; Lefeber, Dirk; Cherelle, Pierre

2013-12-01

The aim of this paper is to present the design of device for control of new propulsion system with pneumatic artificial muscles. The propulsion system can be used for ankle joint articulation, for assisting and rehabilitation in cases of injured ankle-foot complex, stroke patients or elderly with functional weakness. Proposed device for control is composed by microcontroller, generator for muscles contractions and sensor system. The microcontroller receives the control signals from sensors and modulates ankle joint flex- ion and extension during human motion. The local joint control with a PID (Proportional-Integral Derivative) position feedback directly calculates desired pressure levels and dictates the necessary contractions. The main goal is to achieve an adaptation of the system and provide the necessary joint torque using position control with feedback.

Identification of Stimulated Sites Using Artificial Neural Networks Based on Transcranial Magnetic Stimulation-Elicited Motor Evoked Potentials and Finger Forces

NASA Astrophysics Data System (ADS)

Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu

Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) vary in their amplitude from trial to trial. To investigate the functions of motor cortex by TMS, it is necessary to confirm the causal relationship between stimulated sites and variable MEPs. We created artificial neural networks to classify sets of variable MEP signals and finger forces into the corresponding stimulated sites. We conducted TMS at three different positions over M1 and measured MEPs of hand and forearm muscles and forces of the index finger in four subjects. We estimated the sites within motor cortex stimulated by TMS based on cortical columnar structure and nerve excitation properties. Finally, we tried to classify the various MEPs and finger forces into three groups using artificial neural networks. MEPs and finger forces varied from trial to trial, even if the stimulating coil was fixed on the subject's head. Our proposed neural network was able to identify the MEPs and finger forces with the corresponding stimulated sites in M1. We proposed the artificial neural networks to confirm the TMS-stimulated sites using various MEPs and evoked finger forces.

Multi-layer robot skin with embedded sensors and muscles

NASA Astrophysics Data System (ADS)

Tomar, Ankit; Tadesse, Yonas

2016-04-01

Soft artificial skin with embedded sensors and actuators is proposed for a crosscutting study of cognitive science on a facial expressive humanoid platform. This paper focuses on artificial muscles suitable for humanoid robots and prosthetic devices for safe human-robot interactions. Novel composite artificial skin consisting of sensors and twisted polymer actuators is proposed. The artificial skin is conformable to intricate geometries and includes protective layers, sensor layers, and actuation layers. Fluidic channels are included in the elastomeric skin to inject fluids in order to control actuator response time. The skin can be used to develop facially expressive humanoid robots or other soft robots. The humanoid robot can be used by computer scientists and other behavioral science personnel to test various algorithms, and to understand and develop more perfect humanoid robots with facial expression capability. The small-scale humanoid robots can also assist ongoing therapeutic treatment research with autistic children. The multilayer skin can be used for many soft robots enabling them to detect both temperature and pressure, while actuating the entire structure.

The Artificial Gravity Bed Rest Pilot Project: Effects on Knee Extensor and Plantar Flexor Muscle Groups

NASA Technical Reports Server (NTRS)

Caiozzo, V. J.; Haddad, F.; Lee, S.; Baker, M.; Baldwin, K. M.

2007-01-01

The goal of this project was to examine the effects of artificial gravity (2.5 g) on skeletal muscle strength and key anabolic/catabolic markers known to regulate muscle mass. Two groups of subjects were selected for study: 1) a 21 day-bed rest (BR) control (C) group (N=7); and 2) an AG group (N=8), which was exposed to 21 days of bed-rest plus daily 1 hr exposures to AG (2.5 g). This particular experiment was part of an integrated AG Pilot Project sponsored by NASA/Johnson Space Center. The in vivo torque-velocity relationships of the knee extensors and plantar flexors of the ankle were determined pre and post treatment. Also, pre- and post treatment biopsy samples were obtained from both the vastus lateralis and soleus muscles and were used, in part, for a series of analyses on gene expression (mRNA abundance) of key factors implicated in the anabolic versus catabolic state of the muscle. Post/Pre toque-velocity determinations revealed greater decrements in knee extensor performance in the C versus AG group (P less than 0.04). The plantar flexor muscle group of the AG subjects actually demonstrated a net gain in torque-velocity relationship; whereas, in the C group the overall post/pre responses declined (AG vs C; P less than 0.001). Measurements of muscle fiber cross-sectional area (for both muscles) demonstrated a loss of approx. 20% in the C group while no losses were evident in the AG group. RT-PCR analyses of muscle biopsy specimens demonstrated that markers of growth and cytoskeletal integrity (IGF-1, IGF-1 BP4, mechano growth factor, total RNA, and pro-collagen 3a) were higher in the AG group, whereas catabolic markers (myostatin and atrogen) were elevated in the C group. Importantly, these patterns were seen in both muscles. Based on these observations we conclude that paradigms of AG have the potential to maintain the functional, biochemical, and structural homeostasis of skeletal muscle in the face of chronic unloading states. These findings also warrant further studies since it is likely that other robust paradigms of AG that employ various exercise strategies may be more effective in counteracting long duration unloading states as anticipated on the platforms of the Moon and Mars.

Dynamic Analysis Method for Electromagnetic Artificial Muscle Actuator under PID Control

NASA Astrophysics Data System (ADS)

Nakata, Yoshihiro; Ishiguro, Hiroshi; Hirata, Katsuhiro

We have been studying an interior permanent magnet linear actuator for an artificial muscle. This actuator mainly consists of a mover and stator. The mover is composed of permanent magnets, magnetic cores and a non-magnetic shaft. The stator is composed of 3-phase coils and a back yoke. In this paper, the dynamic analysis method under PID control is proposed employing the 3-D finite element method (3-D FEM) to compute the dynamic response and current response when the positioning control is active. As a conclusion, computed results show good agreement with measured ones of a prototype.

Preparation and Characterizing of PANI/PDMS Elastomer for Artificial Muscles

NASA Astrophysics Data System (ADS)

Zhang, Yiyang; Zhang, Jie; Wang, Genlin; Zhang, Ming; Luo, Zhiwei

2018-01-01

A dielectric elastomer has been synthesized using organic soluble PANI and PDMS through solution blending method for applications as artificial muscles. The dielectric constant of PANI/PDMS composite reached 4.82 with a filling amount of 0.8 wt.%, which was 2.24 times of pure silicone, due to the dipole polarization in matrix network and electron polarization in conductive polyaniline. The actuated strain of 0.8w.t % PANI/PDMS was 16.57% compared to 8.52% of pure silicone at an electric field of 10V/μm, and can be applied as a soft actuator.

Artificial intelligence and bladder cancer arrays.

PubMed

Wild, P J; Catto, J W F; Abbod, M F; Linkens, D A; Herr, A; Pilarsky, C; Wissmann, C; Stoehr, R; Denzinger, S; Knuechel, R; Hamdy, F C; Hartmann, A

2007-01-01

Non-muscle invasive bladder cancer is a heterogenous disease whose management is dependent upon the risk of progression to muscle invasion. Although the recurrence rate is high, the majority of tumors are indolent and can be managed by endoscopic means alone. The prognosis of muscle invasion is poor and radical treatment is required if cure is to be obtained. Progression risk in non-invasive tumors is hard to determine at tumor diagnosis using current clinicopathological means. To improve the accuracy of progression prediction various biomarkers have been evaluated. To discover novel biomarkers several authors have used gene expression microarrays. Various statistical methods have been described to interpret array data, but to date no biomarkers have entered clinical practice. Here, we describe a new method of microarray analysis using neurofuzzy modeling (NFM), a form of artificial intelligence, and integrate it with artificial neural networks (ANN) to investigate non-muscle invasive bladder cancer array data (n=66 tumors). We develop a predictive panel of 11 genes, from 2800 expressed genes, that can significantly identify tumor progression (average Logrank p = 0.0288) in the analyzed cancers. In comparison, this panel appears superior to those genes chosen using traditional analyses (average Logrank p = 0.3455) and tumor grade (Logrank, p = 0.2475) in this non-muscle invasive cohort. We then analyze panel members in a new non-muscle invasive bladder cancer cohort (n=199) using immunohistochemistry with six commercially available antibodies. The combination of 6 genes (LIG3, TNFRSF6, KRT18, ICAM1, DSG2 and BRCA2) significantly stratifies tumor progression (Logrank p = 0.0096) in the new cohort. We discuss the benefits of the transparent NFM approach with respect to other reported methods.

A Control Scheme That Uses Dynamic Postural Synergies to Coordinate a Hybrid Walking Neuroprosthesis: Theory and Experiments.

PubMed

Alibeji, Naji A; Molazadeh, Vahidreza; Dicianno, Brad E; Sharma, Nitin

2018-01-01

A hybrid walking neuroprosthesis that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton can be used to restore walking in persons with paraplegia. It provides therapeutic benefits of FES and torque reliability of the powered exoskeleton. Moreover, by harnessing metabolic power of muscles via FES, the hybrid combination has a potential to lower power consumption and reduce actuator size in the powered exoskeleton. Its control design, however, must overcome the challenges of actuator redundancy due to the combined use of FES and electric motor. Further, dynamic disturbances such as electromechanical delay (EMD) and muscle fatigue must be considered during the control design process. This ensures stability and control performance despite disparate dynamics of FES and electric motor. In this paper, a general framework to coordinate FES of multiple gait-governing muscles with electric motors is presented. A muscle synergy-inspired control framework is used to derive the controller and is motivated mainly to address the actuator redundancy issue. Dynamic postural synergies between FES of the muscles and the electric motors were artificially generated through optimizations and result in key dynamic postures when activated. These synergies were used in the feedforward path of the control system. A dynamic surface control technique, modified with a delay compensation term, is used as the feedback controller to address model uncertainty, the cascaded muscle activation dynamics, and EMD. To address muscle fatigue, the stimulation levels in the feedforward path were gradually increased based on a model-based fatigue estimate. A Lyapunov-based stability approach was used to derive the controller and guarantee its stability. The synergy-based controller was demonstrated experimentally on an able-bodied subject and person with an incomplete spinal cord injury.

Prevention of bone loss and muscle atrophy during manned space flight.

PubMed

Keller, T S; Strauss, A M; Szpalski, M

1992-04-01

This paper reviews the biomedical literature concerning human adaptation to nonterrestrial environments, and focuses on the definition of practical countermeasures necessary for long-term survival on the Moon, Mars and during long-term space missions and exploration. Of particular importance is the development of clinically relevant countermeasures for prevention of pathophysiological changes in the musculoskeletal and cardiopulmonary systems under these conditions. The countermeasures which are proposed are based upon a combination of biomechanical and theoretical analyses. The biomechanical analyses are based upon clinical measurements of human skeletal density changes associated with weight lifting as well as clinical studies of human strength and fitness currently being conducted using an isoinertial trunk dynamometer. The theoretical analysis stems from a mathematical model for bone loss in altered gravity environments that we have begun to develop. These analyses provide guidelines for the development of practical therapeutic treatments (exercise, artificial gravity) designed to minimize musculoskeletal deconditioning associated with less than Earth gravity environments. Our findings suggest that very intensive exercise, which impose high loads on the musculoskeletal system for brief periods, may be more efficient in preserving bone and skeletal muscle conditioning within "safe" limits for longer periods than low intensity activities such as treadmill running and bicycling. A 1/6 to 1/7-g gravitational environment is predicted to be sufficient to preserve bone strength above the fracture risk level. Basic biomedical support of manned space missions, Moon and Mars bases should include routine assessment of skeletal density, muscle strength, cardiac output and total energy expenditure. This information can be used to periodically re-evaluate exercise programs and or artificial gravity requirements for crew members.

Development of new experimental platform 'MARS'-Multiple Artificial-gravity Research System-to elucidate the impacts of micro/partial gravity on mice.

PubMed

Shiba, Dai; Mizuno, Hiroyasu; Yumoto, Akane; Shimomura, Michihiko; Kobayashi, Hiroe; Morita, Hironobu; Shimbo, Miki; Hamada, Michito; Kudo, Takashi; Shinohara, Masahiro; Asahara, Hiroshi; Shirakawa, Masaki; Takahashi, Satoru

2017-09-07

This Japan Aerospace Exploration Agency project focused on elucidating the impacts of partial gravity (partial g) and microgravity (μg) on mice using newly developed mouse habitat cage units (HCU) that can be installed in the Centrifuge-equipped Biological Experiment Facility in the International Space Station. In the first mission, 12 C57BL/6 J male mice were housed under μg or artificial earth-gravity (1 g). Mouse activity was monitored daily via downlinked videos; μg mice floated inside the HCU, whereas artificial 1 g mice were on their feet on the floor. After 35 days of habitation, all mice were returned to the Earth and processed. Significant decreases were evident in femur bone density and the soleus/gastrocnemius muscle weights of μg mice, whereas artificial 1 g mice maintained the same bone density and muscle weight as mice in the ground control experiment, in which housing conditions in the flight experiment were replicated. These data indicate that these changes were particularly because of gravity. They also present the first evidence that the addition of gravity can prevent decreases in bone density and muscle mass, and that the new platform 'MARS' may provide novel insights on the molecular-mechanisms regulating biological processes controlled by partial g/μg.

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples.

PubMed

Mayer-Scholl, Anne; Pozio, Edoardo; Gayda, Jennifer; Thaben, Nora; Bahn, Peter; Nöckler, Karsten

2017-03-03

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode larvae of the genus Trichinella. The most important sources of human infections worldwide are game meat and pork or pork products. In many countries, the prevention of human trichinellosis is based on the identification of infected animals by means of the artificial digestion of muscle samples from susceptible animal carcasses. There are several methods based on the digestion of meat but the magnetic stirrer method is considered the gold standard. This method allows the detection of Trichinella larvae by microscopy after the enzymatic digestion of muscle samples and subsequent filtration and sedimentation steps. Although this method does not require special and expensive equipment, internal controls cannot be used. Therefore, stringent quality management should be applied throughout the test. The aim of the present work is to provide detailed handling instructions and critical control points of the method to analysts, based on the experience of the European Union Reference Laboratory for Parasites and the National Reference Laboratory of Germany for Trichinella.

Novel adeno-associated viral vector delivering the utrophin gene regulator jazz counteracts dystrophic pathology in mdx mice.

PubMed

Strimpakos, Georgios; Corbi, Nicoletta; Pisani, Cinzia; Di Certo, Maria Grazia; Onori, Annalisa; Luvisetto, Siro; Severini, Cinzia; Gabanella, Francesca; Monaco, Lucia; Mattei, Elisabetta; Passananti, Claudio

2014-09-01

Over-expression of the dystrophin-related gene utrophin represents a promising therapeutic strategy for Duchenne muscular dystrophy (DMD). The strategy is based on the ability of utrophin to functionally replace defective dystrophin. We developed the artificial zinc finger transcription factor "Jazz" that up-regulates both the human and mouse utrophin promoter. We observed a significant recovery of muscle strength in dystrophic Jazz-transgenic mdx mice. Here we demonstrate the efficacy of an experimental gene therapy based on the systemic delivery of Jazz gene in mdx mice by adeno-associated virus (AAV). AAV serotype 8 was chosen on the basis of its high affinity for skeletal muscle. Muscle-specific expression of the therapeutic Jazz gene was enhanced by adding the muscle α-actin promoter to the AAV vector (mAAV). Injection of mAAV8-Jazz viral preparations into mdx mice resulted in muscle-specific Jazz expression coupled with up-regulation of the utrophin gene. We show a significant recovery from the dystrophic phenotype in mAAV8-Jazz-treated mdx mice. Histological and physiological analysis revealed a reduction of fiber necrosis and inflammatory cell infiltration associated with functional recovery in muscle contractile force. The combination of ZF-ATF technology with the AAV delivery can open a new avenue to obtain a therapeutic strategy for treatment of DMD. © 2014 Wiley Periodicals, Inc.

Sensory motor systems of artificial and natural hands.

PubMed

Chappell, Paul H; Cranny, Andy; Cotton, Darryl P J; White, Neil M; Beeby, Steve P

2007-12-01

The surgeon Ambroise Paré designed an anthropomorphic hand for wounded soldiers in the 16th century. Since that time, there have been advances in technology through the use of computer-aided design, modern materials, electronic controllers and sensors to realise artificial hands which have good functionality and reliability. Data from touch, object slip, finger position and temperature sensors, mounted in the fingers and on the palm, can be used in feedback loops to automatically hold objects. A study of the natural neuromuscular systems reveals a complexity which can only in part be realised today with technology. Highlights of the parallels and differences between natural and artificial hands are discussed with reference to the Southampton Hand. The anatomical structure of parts of the natural systems can be made artificially such as the antagonist muscles using tendons. Theses solutions look promising as they are based on the natural form but in practice lack the desired physical specification. However, concepts of the lower spinal loops can be mimicked in principle. Some future devices will require greater skills from the surgeon to create the interface between the natural system and an artificial device. Such developments may offer a more natural control with ease of use for the limb deficient person.

Nature as an engineer: one simple concept of a bio-inspired functional artificial muscle.

PubMed

Schmitt, S; Haeufle, D F B; Blickhan, R; Günther, M

2012-09-01

The biological muscle is a powerful, flexible and versatile actuator. Its intrinsic characteristics determine the way how movements are generated and controlled. Robotic and prosthetic applications expect to profit from relying on bio-inspired actuators which exhibit natural (muscle-like) characteristics. As of today, when constructing a technical actuator, it is not possible to copy the exact molecular structure of a biological muscle. Alternatively, the question may be put how its characteristics can be realized with known mechanical components. Recently, a mechanical construct for an artificial muscle was proposed, which exhibits hyperbolic force-velocity characteristics. In this paper, we promote the constructing concept which is made by substantiating the mechanical design of biological muscle by a simple model, proving the feasibility of its real-world implementation, and checking their output both for mutual consistency and agreement with biological measurements. In particular, the relations of force, enthalpy rate and mechanical efficiency versus contraction velocity of both the construct's technical implementation and its numerical model were determined in quick-release experiments. All model predictions for these relations and the hardware results are now in good agreement with the biological literature. We conclude that the construct represents a mechanical concept of natural actuation, which is suitable for laying down some useful suggestions when designing bio-inspired actuators.

Biomimetic actuators using electroactive polymers (EAP) as artificial muscles

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2006-01-01

Evolution has resolved many of nature's challenges leading to lasting solutions with maximal performance and effective use of resources. Nature's inventions have always inspired human achievements leading to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems and many other benefits. The field of mimicking nature is known as Biomimetics and one of its topics includes electroactive polymers that gain the moniker artificial muscles. Integrating EAP with embedded sensors, self-repair and many other capabilities that are used in composite materials can add greatly to the capability of smart biomimetic systems. Such development would enable fascinating possibilities potentially turning science fiction ideas into engineering reality.

Electrochemical characterization and control of triple-layer muscles

NASA Astrophysics Data System (ADS)

Otero, Toribio F.; Cortes, Maria T.

2000-06-01

The electrochemical characterization of triple-layers formed by a EPA (Electroactive Polymer)/double-sided tape/EPA, like artificial muscles is described. Those muscles were characterized working under constant potential or under constant current. Due to the electrochemical nature of the electrochemomechanical property, muscles working under constant current produce constant movements, consuming increasing energies at decreasing temperatures, decreasing concentrations of electrolytes or trailing increasing masses. Muscles working at constant potential response with a faster movement if the temperature or the concentration of the electrolyte increase, or if the trailed weight decreases. Specific charges and specific energies were determined for every experimental condition.

Disuse of the musculo-skeletal system in space and on earth.

PubMed

Narici, M V; de Boer, M D

2011-03-01

Muscle mass and strength are well known to decline in response to actual and simulated microgravity exposure. However, despite the considerable knowledge gained on the physiological changes induced by spaceflight, the mechanisms of muscle atrophy and the effectiveness of in-flight countermeasures still need to be fully elucidated. The present review examines the effects and mechanisms of actual and simulated microgravity on single fibre and whole muscle structural and functional properties, protein metabolism, tendon mechanical properties, neural drive and reflex excitability. The effects of inflight countermeasures are also discussed in the light of recent advances in resistive loading techniques, in combined physical, pharmacological and nutritional interventions as well as in the development of artificial gravity systems. Emphasis has been given to the pioneering work of Pietro Enrico di Prampero in the development of artificial gravity systems and in the progress of knowledge on the limits of human muscular performance in space.

Estimation of elbow flexion force during isometric muscle contraction from mechanomyography and electromyography.

PubMed

Youn, Wonkeun; Kim, Jung

2010-11-01

Mechanomyography (MMG) is the muscle surface oscillations that are generated by the dimensional change of the contracting muscle fibers. Because MMG reflects the number of recruited motor units and their firing rates, just as electromyography (EMG) is influenced by these two factors, it can be used to estimate the force exerted by skeletal muscles. The aim of this study was to demonstrate the feasibility of MMG for estimating the elbow flexion force at the wrist under an isometric contraction by using an artificial neural network in comparison with EMG. We performed experiments with five subjects, and the force at the wrist and the MMG from the contributing muscles were recorded. It was found that MMG could be utilized to accurately estimate the isometric elbow flexion force based on the values of the normalized root mean square error (NRMSE = 0.131 ± 0.018) and the cross-correlation coefficient (CORR = 0.892 ± 0.033). Although MMG can be influenced by the physical milieu/morphology of the muscle and EMG performed better than MMG, these experimental results suggest that MMG has the potential to estimate muscle forces. These experimental results also demonstrated that MMG in combination with EMG resulted in better performance estimation in comparison with EMG or MMG alone, indicating that a combination of MMG and EMG signals could be used to provide complimentary information on muscle contraction.

Real-time controller for foot-drop correction by using surface electromyography sensor.

PubMed

Al Mashhadany, Yousif I; Abd Rahim, Nasrudin

2013-04-01

Foot drop is a disease caused mainly by muscle paralysis, which incapacitates the nerves generating the impulses that control feet in a heel strike. The incapacity may stem from lesions that affect the brain, the spinal cord, or peripheral nerves. The foot becomes dorsiflexed, affecting normal walking. A design and analysis of a controller for such legs is the subject of this article. Surface electromyography electrodes are connected to the skin surface of the human muscle and work on the mechanics of human muscle contraction. The design uses real surface electromyography signals for estimation of the joint angles. Various-speed flexions and extensions of the leg were analyzed. The two phases of the design began with surface electromyography of real human leg electromyography signal, which was subsequently filtered, amplified, and normalized to the maximum amplitude. Parameters extracted from the surface electromyography signal were then used to train an artificial neural network for prediction of the joint angle. The artificial neural network design included various-speed identification of the electromyography signal and estimation of the angles of the knee and ankle joints by a recognition process that depended on the parameters of the real surface electromyography signal measured through real movements. The second phase used artificial neural network estimation of the control signal, for calculation of the electromyography signal to be stimulated for the leg muscle to move the ankle joint. Satisfactory simulation (MATLAB/Simulink version 2012a) and implementation results verified the design feasibility.

Regeneration and Maintenance of Intestinal Smooth Muscle Phenotypes

NASA Astrophysics Data System (ADS)

Walthers, Christopher M.

Tissue engineering is an emerging field of biomedical engineering that involves growing artificial organs to replace those lost to disease or injury. Within tissue engineering, there is a demand for artificial smooth muscle to repair tissues of the digestive tract, bladder, and vascular systems. Attempts to develop engineered smooth muscle tissues capable of contracting with sufficient strength to be clinically relevant have so far proven unsatisfactory. The goal of this research was to develop and sustain mature, contractile smooth muscle. Survival of implanted SMCs is critical to sustain the benefits of engineered smooth muscle. Survival of implanted smooth muscle cells was studied with layered, electrospun polycaprolactone implants with lasercut holes ranging from 0--25% porosity. It was found that greater angiogenesis was associated with increased survival of implanted cells, with a large increase at a threshold between 20% and 25% porosity. Heparan sulfate coatings improved the speed of blood vessel infiltration after 14 days of implantation. With these considerations, thicker engineered tissues may be possible. An improved smooth muscle tissue culture technique was utilized. Contracting smooth muscle was produced in culture by maintaining the native smooth muscle tissue organization, specifically by sustaining intact smooth muscle strips rather than dissociating tissue in to isolated smooth muscle cells. Isolated cells showed a decrease in maturity and contained fewer enteric neural and glial cells. Muscle strips also exhibited periodic contraction and regular fluctuation of intracellular calclium. The muscle strip maturity persisted after implantation in omentum for 14 days on polycaprolactone scaffolds. A low-cost, disposable bioreactor was developed to further improve maturity of cultured smooth muscle cells in an environment of controlled cyclical stress.The bioreactor consistently applied repeated mechanical strain with controllable inputs for strain, frequency, and duty cycle. Cells grown on protein-conjugated silicone membranes showed a morphological change while undergoing bioreactor stress. Analyzing change in muscle strips undergoing bioreactor stress is an area for future research. The overall goal of this research was to move engineered smooth muscle towards tissues capable of contracting with physiologically relevant strength and frequency. This approach first increased survival of smooth muscle constructs, and then sought to improve contractile ability of smooth muscle cells.

Novel Adeno-Associated Viral Vector Delivering the Utrophin Gene Regulator Jazz Counteracts Dystrophic Pathology in mdx Mice

PubMed Central

Strimpakos, Georgios; Corbi, Nicoletta; Pisani, Cinzia; Di Certo, Maria Grazia; Onori, Annalisa; Luvisetto, Siro; Severini, Cinzia; Gabanella, Francesca; Monaco, Lucia; Mattei, Elisabetta; Passananti, Claudio

2014-01-01

Over-expression of the dystrophin-related gene utrophin represents a promising therapeutic strategy for Duchenne muscular dystrophy (DMD). The strategy is based on the ability of utrophin to functionally replace defective dystrophin. We developed the artificial zinc finger transcription factor “Jazz” that up-regulates both the human and mouse utrophin promoter. We observed a significant recovery of muscle strength in dystrophic Jazz-transgenic mdx mice. Here we demonstrate the efficacy of an experimental gene therapy based on the systemic delivery of Jazz gene in mdx mice by adeno-associated virus (AAV). AAV serotype 8 was chosen on the basis of its high affinity for skeletal muscle. Muscle-specific expression of the therapeutic Jazz gene was enhanced by adding the muscle α-actin promoter to the AAV vector (mAAV). Injection of mAAV8-Jazz viral preparations into mdx mice resulted in muscle-specific Jazz expression coupled with up-regulation of the utrophin gene. We show a significant recovery from the dystrophic phenotype in mAAV8-Jazz-treated mdx mice. Histological and physiological analysis revealed a reduction of fiber necrosis and inflammatory cell infiltration associated with functional recovery in muscle contractile force. The combination of ZF-ATF technology with the AAV delivery can open a new avenue to obtain a therapeutic strategy for treatment of DMD. J. Cell. Physiol. 229: 1283–1291, 2014. © 2014 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. PMID:24469912

A multi-responsive water-driven actuator with instant and powerful performance for versatile applications

NASA Astrophysics Data System (ADS)

Mu, Jiuke; Hou, Chengyi; Zhu, Bingjie; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong

2015-03-01

Mechanical actuators driven by water that respond to multiple stimuli, exhibit fast responses and large deformations, and generate high stress have potential in artificial muscles, motors, and generators. Meeting all these requirements in a single device remains a challenge. We report a graphene monolayer paper that undergoes reversible deformation. Its graphene oxide cells wrinkle and extend in response to water desorption and absorption, respectively. Its fast (~0.3 s), powerful (>100 MPa output stress, 7.5 × 105 N kg-1 unit mass force), and controllable actuation can be triggered by moisture, heat, and light. The graphene monolayer paper has potential in artificial muscles, robotic hands, and electromagnetic-free generators.

Use of proficiency samples to assess diagnostic laboratories in France performing a Trichinella digestion assay.

PubMed

Vallée, Isabelle; Macé, Pauline; Forbes, Lorry; Scandrett, Brad; Durand, Benoit; Gajadhar, Alvin; Boireau, Pascal

2007-07-01

Routine diagnosis of animal trichinellosis for food safety and trade relies on a method of artificial digestion to free Trichinella muscle larvae from meat for subsequent identification by microscopy. As part of a quality control system, the French National Reference Laboratory (NRL) initiated ring trials to determine the sensitivity of the test performed in the 72 routine diagnostic laboratories in France. A method was devised to obtain calibrated meat samples containing known numbers of capsules with Trichinella spiralis muscle larvae. This method was based on an incomplete artificial digestion of Trichinella-infected mice carcasses to allow the collection of intact Trichinella capsules. Capsules were placed into a meatball of 100 +/- 2 g of pork and horsemeat to produce proficiency samples. Three categories of samples were prepared: small (3 to 5 capsules), medium (7 to 10), and large (12 to 15). The sensitivity was expressed as the percentage of muscle larvae recovered from each proficiency sample. Reproducibility was tested with ring trials organized between two NRLs (France and Canada), and a reference sensitivity of 84.9% was established. National ring trials were then organized in France, with the 72 routine diagnostic laboratories each receiving four proficiency samples per session. After five sessions, an improvement in the digest test sensitivity was observed. Results at the fifth session indicated sensitivities of 78.60% +/- 23.70%, 81.19% +/- 19.59%, and 80.52% +/- 14.71% muscle larvae for small, medium, and large samples, respectively. This study supports the use of proficiency samples to accurately evaluate the performance of routine diagnostic laboratories that conduct digestion tests for animal trichinellosis diagnosis.

Relationship between input power and power density of SMA spring

NASA Astrophysics Data System (ADS)

Park, Cheol Hoon; Ham, Sang Yong; Son, Young Su

2016-04-01

The important required characteristics of an artificial muscle for a human arm-like manipulator are high strain and high power density. From this viewpoint, an SMA (shape memory alloy) spring is a good candidate for the actuator of a robotic manipulator that utilizes an artificial muscle. In this study, the maximum power density of an SMA spring was evaluated with respect to the input power. The spring samples were fabricated from SMA wires of different diameters ranging between 0.1 and 0.3 mm. For each diameter, two types of wires with different transition temperatures were used. The relationship between the transition temperature and maximum power density was also evaluated. Each SMA spring was stretched downward by an attached weight and the temperature was increased through the application of an electric current. The displacement, velocity, and temperature of the SMA spring were measured by laser displacement sensors and a thermocouple. Based on the experimental data, it was determined that the maximum power densities of the different SMA springs ranged between 1,300 and 5,500 W/kg. This confirmed the applicability of an SMA spring to human arm-like robotic manipulators. The results of this study can be used as reference for design.

Development of a soft untethered robot using artificial muscle actuators

NASA Astrophysics Data System (ADS)

Cao, Jiawei; Qin, Lei; Lee, Heow Pueh; Zhu, Jian

2017-04-01

Soft robots have attracted much interest recently, due to their potential capability to work effectively in unstructured environment. Soft actuators are key components in soft robots. Dielectric elastomer actuators are one class of soft actuators, which can deform in response to voltage. Dielectric elastomer actuators exhibit interesting attributes including large voltage-induced deformation and high energy density. These attributes make dielectric elastomer actuators capable of functioning as artificial muscles for soft robots. It is significant to develop untethered robots, since connecting the cables to external power sources greatly limits the robots' functionalities, especially autonomous movements. In this paper we develop a soft untethered robot based on dielectric elastomer actuators. This robot mainly consists of a deformable robotic body and two paper-based feet. The robotic body is essentially a dielectric elastomer actuator, which can expand or shrink at voltage on or off. In addition, the two feet can achieve adhesion or detachment based on the mechanism of electroadhesion. In general, the entire robotic system can be controlled by electricity or voltage. By optimizing the mechanical design of the robot (the size and weight of electric circuits), we put all these components (such as batteries, voltage amplifiers, control circuits, etc.) onto the robotic feet, and the robot is capable of realizing autonomous movements. Experiments are conducted to study the robot's locomotion. Finite element method is employed to interpret the deformation of dielectric elastomer actuators, and the simulations are qualitatively consistent with the experimental observations.

Continuum robot arms inspired by cephalopods

NASA Astrophysics Data System (ADS)

Walker, Ian D.; Dawson, Darren M.; Flash, Tamar; Grasso, Frank W.; Hanlon, Roger T.; Hochner, Binyamin; Kier, William M.; Pagano, Christopher C.; Rahn, Christopher D.; Zhang, Qiming M.

2005-05-01

In this paper, we describe our recent results in the development of a new class of soft, continuous backbone ("continuum") robot manipulators. Our work is strongly motivated by the dexterous appendages found in cephalopods, particularly the arms and suckers of octopus, and the arms and tentacles of squid. Our ongoing investigation of these animals reveals interesting and unexpected functional aspects of their structure and behavior. The arrangement and dynamic operation of muscles and connective tissue observed in the arms of a variety of octopus species motivate the underlying design approach for our soft manipulators. These artificial manipulators feature biomimetic actuators, including artificial muscles based on both electro-active polymers (EAP) and pneumatic (McKibben) muscles. They feature a "clean" continuous backbone design, redundant degrees of freedom, and exhibit significant compliance that provides novel operational capacities during environmental interaction and object manipulation. The unusual compliance and redundant degrees of freedom provide strong potential for application to delicate tasks in cluttered and/or unstructured environments. Our aim is to endow these compliant robotic mechanisms with the diverse and dexterous grasping behavior observed in octopuses. To this end, we are conducting fundamental research into the manipulation tactics, sensory biology, and neural control of octopuses. This work in turn leads to novel approaches to motion planning and operator interfaces for the robots. The paper describes the above efforts, along with the results of our development of a series of continuum tentacle-like robots, demonstrating the unique abilities of biologically-inspired design.

Designing micro- and nanostructures for artificial urinary sphincters

NASA Astrophysics Data System (ADS)

Weiss, Florian M.; Deyhle, Hans; Kovacs, Gabor; Müller, Bert

2012-04-01

The dielectric elastomers are functional materials that have promising potential as actuators with muscle-like mechanical properties due to their inherent compliancy and overall performance: the combination of large deformations, high energy densities and unique sensory capabilities. Consequently, such actuators should be realized to replace the currently available artificial urinary sphincters building dielectric thin film structures that work with several 10 V. The present communication describes the determination of the forces (1 - 10 N) and deformation levels (~10%) necessary for the appropriate operation of the artificial sphincter as well as the response time to master stress incontinence (reaction time less than 0.1 s). Knowing the dimensions of the presently used artificial urinary sphincters, these macroscopic parameters form the basis of the actuator design. Here, we follow the strategy to start from organic thin films maybe even monolayers, which should work with low voltages but only provide small deformations. Actuators out of 10,000 or 100,000 layers will finally provide the necessary force. The suitable choice of elastomer and electrode materials is vital for the success. As the number of incontinent patients is steadily increasing worldwide, it becomes more and more important to reveal the sphincter's function under static and stress conditions to realize artificial urinary sphincters, based on sophisticated, biologically inspired concepts to become nature analogue.

Investigation into response characteristics of the chitosan gel artificial muscle

NASA Astrophysics Data System (ADS)

Zhao, Gang; Yang, Junjie; Wang, Yujian; Zhao, Honghao; Fu, Yu; Zhang, Guangli; Yu, Shuqin; Wu, Yuda; Wei, Chengye; Liu, Xuxiong; Wang, Zhijie

2018-01-01

Bionic artificial muscle made from chitosan gel is an emerging type of the ionic electro active polymer with advantages of large deformation, low cost and environmental protection etc, which leads to a research focus and wide application in the fields of bionic engineering and intelligence material recently. In this paper, effects and improvement mechanisms of the direct casting and genipin cross-linking processes on response speed properties of the chitosan gel artificial muscle (CGAM) were mainly studied. Based on in-depth analysis of the CGAM response mechanism, a platform was built for testing the response performance of the CGAM, then its equivalent circuit and mathematical models were also established. Furthermore, control experiments were carried out to test and analyze several performances of the CGAM on response speed, electrical conductivity, mechanical properties and microstructure with different control variables. The experimental results illustrated that the CGAM assembled by direct casting enabled its electric actuating membrane and non-metallic electrode membrane tightly attached together with low contact resistance, which dramatically promoted the electrical conductivity of the CGAM resulting in nearly doubled response speed. Besides, different concentrations of genipin were adopted to cross-link the CGAM actuating membranes, and then it was found that the response speed of the uncross-linked CGAM was fast in the initial stage, but as time increased, it declined rapidly with poor steadiness. While there was no obvious decrease over time on the response speed of the CGAM cross-linked with low genipin concentration. Namely, its stability was getting better and better. In addition, the response speed of the CGAM cross-linked with low concentration of genipin was roughly the same as uncross-linked CGAM, which was quicker than that of high concentration. In this work, its internal mechanisms, feasible assembly technique and green modification method were provided to further explore the practical applications significantly.

A benchtop biorobotic platform for in vitro observation of muscle-tendon dynamics with parallel mechanical assistance from an elastic exoskeleton.

PubMed

Robertson, Benjamin D; Vadakkeveedu, Siddarth; Sawicki, Gregory S

2017-05-24

We present a novel biorobotic framework comprised of a biological muscle-tendon unit (MTU) mechanically coupled to a feedback controlled robotic environment simulation that mimics in vivo inertial/gravitational loading and mechanical assistance from a parallel elastic exoskeleton. Using this system, we applied select combinations of biological muscle activation (modulated with rate-coded direct neural stimulation) and parallel elastic assistance (applied via closed-loop mechanical environment simulation) hypothesized to mimic human behavior based on previously published modeling studies. These conditions resulted in constant system-level force-length dynamics (i.e., stiffness), reduced biological loads, increased muscle excursion, and constant muscle average positive power output-all consistent with laboratory experiments on intact humans during exoskeleton assisted hopping. Mechanical assistance led to reduced estimated metabolic cost and MTU apparent efficiency, but increased apparent efficiency for the MTU+Exo system as a whole. Findings from this study suggest that the increased natural resonant frequency of the artificially stiffened MTU+Exo system, along with invariant movement frequencies, may underlie observed limits on the benefits of exoskeleton assistance. Our novel approach demonstrates that it is possible to capture the salient features of human locomotion with exoskeleton assistance in an isolated muscle-tendon preparation, and introduces a powerful new tool for detailed, direct examination of how assistive devices affect muscle-level neuromechanics and energetics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogel ionotronics

NASA Astrophysics Data System (ADS)

Yang, Canhui; Suo, Zhigang

2018-06-01

An ionotronic device functions by a hybrid circuit of mobile ions and mobile electrons. Hydrogels are stretchable, transparent, ionic conductors that can transmit electrical signals of high frequency over long distance, enabling ionotronic devices such as artificial muscles, skins and axons. Moreover, ionotronic luminescent devices, ionotronic liquid crystal devices, touchpads, triboelectric generators, artificial eels and gel-elastomer-oil devices can be designed based on hydrogels. In this Review, we discuss first-generation hydrogel ionotronic devices and the challenges associated with the mechanical properties and the chemistry of the materials. We examine how strong and stretchable adhesion between hydrophilic and hydrophobic polymer networks can be achieved, how water can be retained in hydrogels and how to design hydrogels that resist fatigue under cyclic loads. Finally, we highlight applications of hydrogel ionotronic devices and discuss the future of the field.

Upwind methods for the Baer–Nunziato equations and higher-order reconstruction using artificial viscosity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraysse, F., E-mail: francois.fraysse@rs2n.eu; E. T. S. de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Madrid; Redondo, C.

This article is devoted to the numerical discretisation of the hyperbolic two-phase flow model of Baer and Nunziato. A special attention is paid on the discretisation of intercell flux functions in the framework of Finite Volume and Discontinuous Galerkin approaches, where care has to be taken to efficiently approximate the non-conservative products inherent to the model equations. Various upwind approximate Riemann solvers have been tested on a bench of discontinuous test cases. New discretisation schemes are proposed in a Discontinuous Galerkin framework following the criterion of Abgrall and the path-conservative formalism. A stabilisation technique based on artificial viscosity is appliedmore » to the high-order Discontinuous Galerkin method and compared against classical TVD-MUSCL Finite Volume flux reconstruction.« less

Human Electro-Muscular Incapacitation (HEMI) Devices Characterization: A Comparative Study on Stress and the Physiological Effects on Swine

DTIC Science & Technology

2011-07-07

depending upon the device. As noted earlier, while the Stinger™S-200 and TASER ® X26 both resulted in tetany (sustained muscle contraction ), the cyclic...artificially maintained by the muscle contraction of the HEMI application. The stoppage of the HEMI “unmasked” the hypovolemia and the blood pressure...dropped. (2) The animals had normal blood volume with peripheral vascular resistance maintained by the HEMI ( muscle contraction ). When the HEMI

A reconfigurable robot with tensegrity structure using nylon artificial muscle

NASA Astrophysics Data System (ADS)

Wu, Lianjun; de Andrade, Monica Jung; Brahme, Tarang; Tadesse, Yonas; Baughman, Ray H.

2016-04-01

This paper describes the design and experimental investigation of a self-reconfigurable icosahedral robot for locomotion. The robot consists of novel and modular tensegrity structures, which can potentially maneuver in unstructured environments while carrying a payload. Twisted and Coiled Polymer (TCP) muscles were utilized to actuate the tensegrity structure as needed. The tensegrity system has rigid struts and flexible TCP muscles that allow keeping a payload in the central region. The TCP muscles provide large actuation stroke, high mechanical power per fiber mass and can undergo millions of highly reversible cycles. The muscles are electrothermally driven, and, upon stimulus, the heated muscles reconfigure the shape of the tensegrity structure. Here, we present preliminary experimental results that determine the rolling motion of the structure.

Development of soft robots using dielectric elastomer actuators

NASA Astrophysics Data System (ADS)

Godaba, Hareesh; Wang, Yuzhe; Cao, Jiawei; Zhu, Jian

2016-04-01

Soft robots are gaining in popularity due to their unique attributes such as low weight, compliance, flexibility and diverse range in motion types. This paper illustrates soft robots and actuators which are developed using dielectric elastomer. These developments include a jellyfish robot, a worm like robot and artificial muscle actuators for jaw movement in a robotic skull. The jellyfish robot which employs a bulged dielectric elastomer membrane has been demonstrated too generate thrust and buoyant forces and can move effectively in water. The artificial muscle for jaw movement employs a pure shear configuration and has been shown to closely mimic the jaw motion while chewing or singing a song. Thee inchworm robot, powered by dielectric elastomer actuator can demonstrate stable movement in one-direction.

Development of a Wearable Controller for Gesture-Recognition-Based Applications Using Polyvinylidene Fluoride.

PubMed

Van Volkinburg, Kyle; Washington, Gregory

2017-08-01

This paper reports on a wearable gesture-based controller fabricated using the sensing capabilities of the flexible thin-film piezoelectric polymer polyvinylidene fluoride (PVDF) which is shown to repeatedly and accurately discern, in real time, between right and left hand gestures. The PVDF is affixed to a compression sleeve worn on the forearm to create a wearable device that is flexible, adaptable, and highly shape conforming. Forearm muscle movements, which drive hand motions, are detected by the PVDF which outputs its voltage signal to a developed microcontroller-based board and processed by an artificial neural network that was trained to recognize the generated voltage profile of right and left hand gestures. The PVDF has been spatially shaded (etched) in such a way as to increase sensitivity to expected deformations caused by the specific muscles employed in making the targeted right and left gestures. The device proves to be exceptionally accurate both when positioned as intended and when rotated and translated on the forearm.

Development of anthropomorphic robotic hand driven by Pneumatic Artificial Muscles for robotic applications

NASA Astrophysics Data System (ADS)

Farag, Mohannad; Zainul Azlan, Norsinnira; Hayyan Alsibai, Mohammed

2018-04-01

This paper presents the design and fabrication of a three-fingered anthropomorphic robotic hand. The fingers are driven by tendons and actuated by human muscle-like actuators known as Pneumatic Artificial Muscle (PAM). The proposed design allows the actuators to be mounted outside the hand where each finger can be driven by one PAM actuator and six indirectly interlinked tendons. With this design, the three-fingered hand has a compact size and a lightweight with a mass of 150.25 grams imitating the human being hand in terms of size and weight. The hand also successfully grasped objects with different shapes and weights up to 500 g. Even though the number of PAM actuators equals the number of Degrees of Freedom (DOF), the design guarantees driving of three joints by only one actuator reducing the number of required actuators from 3 to 1. Therefore, this hand is suitable for researches of robotic applications in terms of design, cost and ability to be equipped with several types of sensors.

Skeletal muscle is a biological example of a linear electroactive actuator

NASA Astrophysics Data System (ADS)

Lieber, Richard L.

1999-05-01

Skeletal muscle represents a classic biological example of a structure-function relationship. This paper reviews basic muscle anatomy and demonstrates how molecular motion on the order of nm distances is converted into the macroscopic movements that are possible with skeletal muscle. Muscle anatomy provides a structural basis for understanding the basic mechanical properties of skeletal muscle -- namely, the length-tension relationship and the force-velocity relationships. The length-tension relationship illustrates that muscle force generation is extremely length dependent due to the interdigitation of the contractile filaments. The force-velocity relationship is characterized by a rapid force drop in muscle with increasing shortening velocity and a rapid rise in force when muscles are forced to lengthen. Finally, muscle architecture -- the number and arrangement of muscle fibers -- has a profound effect on the magnitude of muscle force generated and the magnitude of muscle excursion. These concepts demonstrate the elegant manner in which muscle acts as a biologically regenerating linear motor. These concepts can be used in developing artificial muscles as well as in performing surgical reconstructive procedures with various donor muscles.

Improvement of McKibben Artificial Muscle with Long Stroke Motion and Its Application

NASA Astrophysics Data System (ADS)

Akagi, Tetsuya; Dohta, Shujiro; Kuno, Hiroaki; Ihara, Michinori

The actuators required for a wearable system need to be flexible so as not to injure the body. The purpose of this study is to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body. In the previous study, a new type of McKibben artificial muscle that had a long stroke of more than 80 % of its original length was proposed and tested. However, the damages on the tube of the actuator were found. They are caused by a large friction between the slide stage and the tube. Therefore, the life time of the actuator becomes shorter. In this paper, the improved McKibben actuator which consists of a McKibben artificial muscle on the market (FESTO Co. Ltd.), steel balls as a cylinder head and two pairs of slide stages is proposed and tested. The slide stage has steel balls set on the inner bore of the stage to decrease the friction. The steel ball in the McKibben actuator is held by two pairs of slide stages from both sides of the ball. As a result, the minimum driving pressure of the improved actuator decreases about 68 % compared with that of the previous one. The actuator can realize both pushing and pulling motion even if it has flexibility. By using these properties of the actuator, the various rehabilitation devices were proposed and tested.

A passive exoskeleton with artificial tendons: design and experimental evaluation.

PubMed

van Dijk, Wietse; van der Kooij, Herman; Hekman, Edsko

2011-01-01

We developed a passive exoskeleton that was designed to minimize joint work during walking. The exoskeleton makes use of passive structures, called artificial tendons, acting in parallel with the leg. Artificial tendons are elastic elements that are able to store and redistribute energy over the human leg joints. The elastic characteristics of the tendons have been optimized to minimize the mechanical work of the human leg joints. In simulation the maximal reduction was 40 percent. The performance of the exoskeleton was evaluated in an experiment in which nine subjects participated. Energy expenditure and muscle activation were measured during three conditions: Normal walking, walking with the exoskeleton without artificial tendons, and walking with the exoskeleton with the artificial tendons. Normal walking was the most energy efficient. While walking with the exoskeleton, the artificial tendons only resulted in a negligibly small decrease in energy expenditure. © 2011 IEEE

Technology Survey for Enhancement of Chemical Biological Radiological and Nuclear Respiratory Protection

DTIC Science & Technology

2008-02-01

goal to develop artificial skins for robots . Thermoelectric devices and miniature blowers and fans were reviewed for cooling applications. The ability of...including medical (e.g., drug delivery, implants), aerospace, textile, robotics (i.e., artificial muscles), and sensors. The technology survey to...implants. ILC Dover is developing a self - repairing space suit that incorporates a pressure sensitive gel (Shiga, 2006). The polymer gel is contained between

Strain-dependent characterization of electrode and polymer network of electrically activated polymer actuators

NASA Astrophysics Data System (ADS)

Töpper, Tino; Osmani, Bekim; Weiss, Florian M.; Winterhalter, Carla; Wohlfender, Fabian; Leung, Vanessa; Müller, Bert

2015-04-01

Fecal incontinence describes the involuntary loss of bowel content and affects about 45 % of retirement home residents and overall more than 12 % of the adult population. Artificial sphincter implants for treating incontinence are currently based on mechanical systems with failure rates resulting in revision after three to five years. To overcome this drawback, artificial muscle sphincters based on bio-mimetic electro-active polymer (EAP) actuators are under development. Such implants require polymer films that are nanometer-thin, allowing actuation below 24 V, and electrodes that are stretchable, remaining conductive at strains of about 10 %. Strain-dependent resistivity measurements reveal an enhanced conductivity of 10 nm compared to 30 nm sputtered Au on silicone for strains higher than 5 %. Thus, strain-dependent morphology characterization with optical microscopy and atomic force microscopy could demonstrate these phenomena. Cantilever bending measurements are utilized to determine elastic/viscoelastic properties of the EAP films as well as their long-term actuation behavior. Controlling these properties enables the adjustment of growth parameters of nanometer-thin EAP actuators.

Artificial voice modulation in dogs by recurrent laryngeal nerve stimulation: electrophysiological confirmation of anatomic data.

PubMed

Broniatowski, Michael; Grundfest-Broniatowski, Sharon; Tucker, Harvey M; Tyler, Dustin J

2007-02-01

We hypothesized that voice may be artificially manipulated to ameliorate dystonias considered to be a failure in dynamic integration between competing neuromuscular systems. Orderly intrinsic laryngeal muscle recruitment by anodal block via the recurrent laryngeal and vagus nerves has allowed us to define specific values based on differential excitabilities, but has precluded voice fluency because of focused breaks during stimulation and the need to treat several neural conduits. Such problems may be obviated by a circuit capable of stimulating some axons while simultaneously blocking others in the recurrent laryngeal nerve, which carries innervation to all intrinsic laryngeal muscles, including the arguably intrinsic cricothyroideus. In 5 dogs, both recurrent laryngeal nerves received 40-Hz quasi-trapezoidal pulses (0 to 2000 microA, 0 to 2000 micros, 0 to 500 micros decay) via tripolar electrodes. Electromyograms were matched with audio intensities and fundamental frequencies recorded under a constant flow of humidified air. Data were digitized and evaluated for potential correlations. Orderly recruitment of the thyroarytenoideus, posterior cricoarytenoideus, and cricothyroideus was correlated with stimulating intensities (p < .001), and posterior cricoarytenoideus opposition to the thyroarytenoideus and cricothyroideus was instrumental in manipulating audio intensities and fundamental frequencies. Manipulation of canine voice parameters appears feasible via the sole recurrent laryngeal nerve within appropriate stimulation envelopes, and offers promise in human laryngeal dystonias.

Bio-inspired online variable recruitment control of fluidic artificial muscles

NASA Astrophysics Data System (ADS)

Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-12-01

This paper details the creation of a hybrid variable recruitment control scheme for fluidic artificial muscle (FAM) actuators with an emphasis on maximizing system efficiency and switching control performance. Variable recruitment is the process of altering a system’s active number of actuators, allowing operation in distinct force regimes. Previously, FAM variable recruitment was only quantified with offline, manual valve switching; this study addresses the creation and characterization of novel, on-line FAM switching control algorithms. The bio-inspired algorithms are implemented in conjunction with a PID and model-based controller, and applied to a simulated plant model. Variable recruitment transition effects and chatter rejection are explored via a sensitivity analysis, allowing a system designer to weigh tradeoffs in actuator modeling, algorithm choice, and necessary hardware. Variable recruitment is further developed through simulation of a robotic arm tracking a variety of spline position inputs, requiring several levels of actuator recruitment. Switching controller performance is quantified and compared with baseline systems lacking variable recruitment. The work extends current variable recruitment knowledge by creating novel online variable recruitment control schemes, and exploring how online actuator recruitment affects system efficiency and control performance. Key topics associated with implementing a variable recruitment scheme, including the effects of modeling inaccuracies, hardware considerations, and switching transition concerns are also addressed.

Artificial Gravity: Will it Preserve Bone Health on Long-Duration Missions?

NASA Technical Reports Server (NTRS)

Davis-Street, Janis; Paloski, William H.

2005-01-01

Prolonged microgravity exposure disrupts bone, muscle, and cardiovascular homeostasis, sensory-motor coordination, immune function, and behavioral performance. Bone loss, in particular, remains a serious impediment to the success of exploration-class missions by increasing the risks of bone fracture and renal stone formation for crew members. Current countermeasures, consisting primarily of resistive and aerobic exercise, have not yet proven fully successful for preventing bone loss during long-duration spaceflight. While other bone-specific countermeasures, such as pharmacological therapy and dietary modifications, are under consideration, countermeasure approaches that simultaneously address multiple physiologic systems may be more desirable for exploration-class missions, particularly if they can provide effective protection at reduced mission resource requirements (up-mass, power, crew time, etc). The most robust of the multi-system approaches under consideration, artificial gravity (AG), could prevent all of the microgravity-related physiological changes from occurring. The potential methods for realizing an artificial gravity countermeasure are reviewed, as well as selected animal and human studies evaluating the effects of artificial gravity on bone function. Future plans for the study of the multi-system effects of artificial gravity include a joint, cooperative international effort that will systematically seek an optimal prescription for intermittent AG to preserve bone, muscle, and cardiovascular function in human subjects deconditioned by 6 degree head-down-tilt-bed rest. It is concluded that AG has great promise as a multi-system countermeasure, but that further research is required to determine the appropriate parameters for implementation of such a countermeasure for exploration-class missions.

A Variance Distribution Model of Surface EMG Signals Based on Inverse Gamma Distribution.

PubMed

Hayashi, Hideaki; Furui, Akira; Kurita, Yuichi; Tsuji, Toshio

2017-11-01

Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this variance. Variance distribution estimation based on marginal likelihood maximization is also outlined in this paper. The procedure can be approximated using rectified and smoothed EMG signals, thereby allowing the determination of distribution parameters in real time at low computational cost. Results: A simulation experiment was performed to evaluate the accuracy of distribution estimation using artificially generated EMG signals, with results demonstrating that the proposed model's accuracy is higher than that of maximum-likelihood-based estimation. Analysis of variance distribution using real EMG data also suggested a relationship between variance distribution and signal-dependent noise. Conclusion: The study reported here was conducted to examine the performance of a proposed surface EMG model capable of representing variance distribution and a related distribution parameter estimation method. Experiments using artificial and real EMG data demonstrated the validity of the model. Significance: Variance distribution estimated using the proposed model exhibits potential in the estimation of muscle force. Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this variance. Variance distribution estimation based on marginal likelihood maximization is also outlined in this paper. The procedure can be approximated using rectified and smoothed EMG signals, thereby allowing the determination of distribution parameters in real time at low computational cost. Results: A simulation experiment was performed to evaluate the accuracy of distribution estimation using artificially generated EMG signals, with results demonstrating that the proposed model's accuracy is higher than that of maximum-likelihood-based estimation. Analysis of variance distribution using real EMG data also suggested a relationship between variance distribution and signal-dependent noise. Conclusion: The study reported here was conducted to examine the performance of a proposed surface EMG model capable of representing variance distribution and a related distribution parameter estimation method. Experiments using artificial and real EMG data demonstrated the validity of the model. Significance: Variance distribution estimated using the proposed model exhibits potential in the estimation of muscle force.

Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques

PubMed Central

Ibrahim, Michael; Rao, Christopher; Athanasiou, Thanos

2012-01-01

The surgical repair of degenerative mitral valve disease involves a number of technical points of importance. The use of artificial chordae for the repair of degenerative disease has increased as a part of the move from mitral valve replacement to repair of the mitral valve. The use of artificial chordae provides an alternative to the techniques pioneered by Carpentier (including the quadrangular resection, transfer of native chordae and papillary muscle shortening/plasty), which can be more technically difficult. Despite a growth in their uptake and the indications for their use, a number of challenges remain for the use of artificial chordae in mitral valve repair, particularly in the determination of the correct length to ensure optimal leaflet coaptation. Here, we analyse over 40 techniques described for artificial chordae mitral valve repair in the setting of degenerative disease. PMID:22962321

A New Approach for Human Forearm Motion Assist by Actuated Artificial Joint-An Inner Skeleton Robot

NASA Astrophysics Data System (ADS)

Kundu, Subrata Kumar; Kiguchi, Kazuo; Teramoto, Kenbu

In order to help the physical activities of the elderly or physically disabled persons, we propose a new concept of a power-assist inner skeleton robot (i.e., actuated artificial joint) that is supposed to assist the human daily life motion from inside of the human body. This paper presents an implantable 2 degree of freedom (DOF) inner skeleton robot that is designed to assist human elbow flexion-extension motion and forearm supination-pronation motion for daily life activities. We have developed a prototype of the inner skeleton robot that is supposed to assist the motion from inside of the body and act as an actuated artificial joint. The proposed system is controlled based on the activation patterns of the electromyogram (EMG) signals of the user's muscles by applying fuzzy-neuro control method. A joint actuator with angular position sensor is designed for the inner skeleton robot and a T-Mechanism is proposed to keep the bone arrangement similar to the normal human articulation after the elbow arthroplasty. The effectiveness of the proposed system has been evaluated by experiment.

A method for classification of transient events in EEG recordings: application to epilepsy diagnosis.

PubMed

Tzallas, A T; Karvelis, P S; Katsis, C D; Fotiadis, D I; Giannopoulos, S; Konitsiotis, S

2006-01-01

The aim of the paper is to analyze transient events in inter-ictal EEG recordings, and classify epileptic activity into focal or generalized epilepsy using an automated method. A two-stage approach is proposed. In the first stage the observed transient events of a single channel are classified into four categories: epileptic spike (ES), muscle activity (EMG), eye blinking activity (EOG), and sharp alpha activity (SAA). The process is based on an artificial neural network. Different artificial neural network architectures have been tried and the network having the lowest error has been selected using the hold out approach. In the second stage a knowledge-based system is used to produce diagnosis for focal or generalized epileptic activity. The classification of transient events reported high overall accuracy (84.48%), while the knowledge-based system for epilepsy diagnosis correctly classified nine out of ten cases. The proposed method is advantageous since it effectively detects and classifies the undesirable activity into appropriate categories and produces a final outcome related to the existence of epilepsy.

Getting a New Heart

MedlinePlus

... may be able to replace it with an artificial (man-made) valve. Cardiac size reduction . During this procedure, your doctor removes a piece of the heart muscle from an enlarged heart. This makes your ...

Compact and low-cost humanoid hand powered by nylon artificial muscles.

PubMed

Wu, Lianjun; Jung de Andrade, Monica; Saharan, Lokesh Kumar; Rome, Richard Steven; Baughman, Ray H; Tadesse, Yonas

2017-02-03

This paper focuses on design, fabrication and characterization of a biomimetic, compact, low-cost and lightweight 3D printed humanoid hand (TCP Hand) that is actuated by twisted and coiled polymeric (TCP) artificial muscles. The TCP muscles were recently introduced and provided unprecedented strain, mechanical work, and lifecycle (Haines et al 2014 Science 343 868-72). The five-fingered humanoid hand is under-actuated and has 16 degrees of freedom (DOF) in total (15 for fingers and 1 at the palm). In the under-actuated hand designs, a single actuator provides coupled motions at the phalanges of each finger. Two different designs are presented along with the essential elements consisting of actuators, springs, tendons and guide systems. Experiments were conducted to investigate the performance of the TCP muscles in response to the power input (power magnitude, type of wave form such as pulsed or square wave, and pulse duration) and the resulting actuation stroke and force generation. A kinematic model of the flexor tendons was developed to simulate the flexion motion and compare with experimental results. For fast finger movements, short high-power pulses were employed. Finally, we demonstrated the grasping of various objects using the humanoid TCP hand showing an array of functions similar to a natural hand.

Therapeutic Plasma Exchange in a rare case myasthenic crisis after Botox injection.

PubMed

Chegini, Azita

2017-11-01

Botulinum toxin (Botox) injections are used as a cosmetic treatment to decrease wrinkles in face and chin. Being a neurotoxic agent it minimizes muscle activity, while side effects are usually rare. This article subsequently presents one case of these rare effects. A 30-year-old woman presenting with ptosis, diplopia, dysarthria, dysphagia and muscle weakness was admitted to our hospital. She had no history of disease. For cosmetic reasons, she had three Botox injections during the preceding months. On physical examination, muscle weakness 4/5 (cervical extensor, ocular and pharynx) was detected and a diagnosis of myasthenia gravis was made. Protective artificial ventilation was necessary. As a consequence, eight sessions of 2.5 L volume Therapeutic Plasma Exchange (TPE) were applied using normal saline/albumin as substitute. Due to TPE, her muscle force and clinical condition improved. Artificial ventilation could be stopped. Clinical symptoms of myasthenia gravis and systemic Botox effects are very similar. This should be taken into consideration during medical history taking. The injection of high doses of Botox (more than 200 units in every injection) or boostering within less than one month is dangerous. (Botox BCC2024). Systemic side effects can be treated using TPE to lower the circulating dose of Botox. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioengineered nerve regeneration and muscle reinnervation

PubMed Central

Kingham, Paul J; Terenghi, Giorgio

2006-01-01

The peripheral nervous system has the intrinsic capacity to regenerate but the reinnervation of muscles is often suboptimal and results in limited recovery of function. Injuries to nerves that innervate complex organs such as the larynx are particularly difficult to treat. The many functions of the larynx have evolved through the intricate neural regulation of highly specialized laryngeal muscles. In this review, we examine the responses of nerves and muscles to injury, focusing on changes in the expression of neurotrophic factors, and highlight differences between the skeletal limb and laryngeal muscle systems. We also describe how artificial nerve conduits have become a useful tool for delivery of neurotrophic factors as therapeutic agents to promote peripheral nerve repair and might eventually be useful in the treatment of laryngeal nerve injury. PMID:17005023

A study on contraction of pneumatic artificial muscle (PAM) for load-lifting

NASA Astrophysics Data System (ADS)

Najmuddin, W. S. W. A.; Mustaffa, M. T.

2017-10-01

Pneumatic Artificial Muscles (PAMs) have been known for its wide application in various aspects of industrial automation and robotic equipments. Many advantages in terms of high power-to-volume ratio, high power-to-weight ratio, stick-slip-free operation and high degree of safety offer by PAM compare to traditional actuators. However, behind this benefits lie a limitation of significant compatibility of PAM mechanism which have to be considered so as to fully understand how the PAM works during load-lifting. In this study, the mesh suitability experiment and the effect of force load on PAM contraction experiment have been carried out. PAM is constructed and compatibility of bladder and the braided mesh to produce uniform expansion is investigated. Moreover, the first experimental result of finding compatibility is used to verify the contraction value under various loads.

Practical controller design for ultra-precision positioning of stages with a pneumatic artificial muscle actuator

NASA Astrophysics Data System (ADS)

Tang, T. F.; Chong, S. H.

2017-06-01

This paper presents a practical controller design method for ultra-precision positioning of pneumatic artificial muscle actuator stages. Pneumatic artificial muscle (PAM) actuators are safe to use and have numerous advantages which have brought these actuators to wide applications. However, PAM exhibits strong non-linear characteristics, and these limitations lead to low controllability and limit its application. In practice, the non-linear characteristics of PAM mechanism are difficult to be precisely modeled, and time consuming to model them accurately. The purpose of the present study is to clarify a practical controller design method that emphasizes a simple design procedure that does not acquire plants parameters modeling, and yet is able to demonstrate ultra-precision positioning performance for a PAM driven stage. The practical control approach adopts continuous motion nominal characteristic trajectory following (CM NCTF) control as the feedback controller. The constructed PAM driven stage is in low damping characteristic and causes severe residual vibration that deteriorates motion accuracy of the system. Therefore, the idea to increase the damping characteristic by having an acceleration feedback compensation to the plant has been proposed. The effectiveness of the proposed controller was verified experimentally and compared with a classical PI controller in point-to-point motion. The experiment results proved that the CM NCTF controller demonstrates better positioning performance in smaller motion error than the PI controller. Overall, the CM NCTF controller has successfully to reduce motion error to 3µm, which is 88.7% smaller than the PI controller.

Carbon-Nanotube Fibers for Wearable Devices and Smart Textiles.

PubMed

Di, Jiangtao; Zhang, Xiaohua; Yong, Zhenzhong; Zhang, Yongyi; Li, Da; Li, Ru; Li, Qingwen

2016-12-01

Carbon-nanotube (CNT) fibers integrate such properties as high mechanical strength, extraordinary structural flexibility, high thermal and electrical conductivities, novel corrosion and oxidation resistivities, and high surface area, which makes them a very promising candidate for next-generation smart textiles and wearable devices. A brief review of the preparation of CNT fibers and recently developed CNT-fiber-based flexible and functional devices, which include artificial muscles, electrochemical double-layer capacitors, lithium-ion batteries, solar cells, and memristors, is presented. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mobile robots: motor challenges and materials solutions.

PubMed

Madden, John D

2007-11-16

Bolted-down robots labor in our factories, performing the same task over and over again. Where are the robots that run and jump? Equaling human performance is very difficult for many reasons, including the basic challenge of demonstrating motors and transmissions that efficiently match the power per unit mass of muscle. In order to exceed animal agility, new actuators are needed. Materials that change dimension in response to applied voltage, so-called artificial muscle technologies, outperform muscle in most respects and so provide a promising means of improving robots. In the longer term, robots powered by atomically perfect fibers will outrun us all.

Intramuscular Contact Lead Filled With Conductive Solution

NASA Technical Reports Server (NTRS)

Bamford, Robert M.; Hendrickson, James A.

1991-01-01

Proposed sheath for braided-wire intramuscular conductor preserves electrical continuity even if wire breaks. Plastic sheath surrounds conductive solution in which braided wire immersed. At end of cable, wire and sheath crimped together and press-fit in porous titanium electrode. Implanted surgically with aid of device resembling catheter. Used to deliver electrical stimuli to muscles in biomedical research on human and animal physiology, development of prostheses, regeneration of nerves and muscles, and artificial implants.

Analysis of Facial Expression by Taste Stimulation

NASA Astrophysics Data System (ADS)

Tobitani, Kensuke; Kato, Kunihito; Yamamoto, Kazuhiko

In this study, we focused on the basic taste stimulation for the analysis of real facial expressions. We considered that the expressions caused by taste stimulation were unaffected by individuality or emotion, that is, such expressions were involuntary. We analyzed the movement of facial muscles by taste stimulation and compared real expressions with artificial expressions. From the result, we identified an obvious difference between real and artificial expressions. Thus, our method would be a new approach for facial expression recognition.

Artificial neural networks applied to quantitative elemental analysis of organic material using PIXE

NASA Astrophysics Data System (ADS)

Correa, R.; Chesta, M. A.; Morales, J. R.; Dinator, M. I.; Requena, I.; Vila, I.

2006-08-01

An artificial neural network (ANN) has been trained with real-sample PIXE (particle X-ray induced emission) spectra of organic substances. Following the training stage ANN was applied to a subset of similar samples thus obtaining the elemental concentrations in muscle, liver and gills of Cyprinus carpio. Concentrations obtained with the ANN method are in full agreement with results from one standard analytical procedure, showing the high potentiality of ANN in PIXE quantitative analyses.

Activation of Actuating Hydrogels with WS2 Nanosheets for Biomimetic Cellular Structures and Steerable Prompt Deformation.

PubMed

Zong, Lu; Li, Xiankai; Han, Xiangsheng; Lv, Lili; Li, Mingjie; You, Jun; Wu, Xiaochen; Li, Chaoxu

2017-09-20

Macroscopic soft actuation is intrinsic to living organisms in nature, including slow deformation (e.g., contraction, bending, twisting, and curling) of plants motivated by microscopic swelling and shrinking of cells, and rapid motion of animals (e.g., deformation of jellyfish) motivated by cooperative nanoscale movement of motor proteins. These actuation behaviors, with an exceptional combination of tunable speed and programmable deformation direction, inspire us to design artificial soft actuators for broad applications in artificial muscles, nanofabrication, chemical valves, microlenses, soft robotics, etc. However, so far artificial soft actuators have been typically produced on the basis of poly(N-isopropylacrylamide) (PNiPAM), whose deformation is motived by volumetric shrinkage and swelling in analogue to plant cells, and exhibits sluggish actuation kinetics. In this study, alginate-exfoliated WS 2 nanosheets were incorporated into ice-template-polymerized PNiPAM hydrogels with the cellular microstructures which mimic plant cells, yet the prompt steerable actuation of animals. Because of the nanosheet-reinforced pore walls formed in situ in freezing polymerization and reasonable hierarchical water channels, this cellular hybrid hydrogel achieves super deformation speed (on the order of magnitude of 10° s), controllable deformation direction, and high near-infrared light responsiveness, offering an unprecedented platform of artificial muscles for various soft robotics and devices (e.g., rotator, microvalve, aquatic swimmer, and water-lifting filter).

Decellularised skeletal muscles allow functional muscle regeneration by promoting host cell migration.

PubMed

Urciuolo, Anna; Urbani, Luca; Perin, Silvia; Maghsoudlou, Panagiotis; Scottoni, Federico; Gjinovci, Asllan; Collins-Hooper, Henry; Loukogeorgakis, Stavros; Tyraskis, Athanasios; Torelli, Silvia; Germinario, Elena; Fallas, Mario Enrique Alvarez; Julia-Vilella, Carla; Eaton, Simon; Blaauw, Bert; Patel, Ketan; De Coppi, Paolo

2018-05-30

Pathological conditions affecting skeletal muscle function may lead to irreversible volumetric muscle loss (VML). Therapeutic approaches involving acellular matrices represent an emerging and promising strategy to promote regeneration of skeletal muscle following injury. Here we investigated the ability of three different decellularised skeletal muscle scaffolds to support muscle regeneration in a xenogeneic immune-competent model of VML, in which the EDL muscle was surgically resected. All implanted acellular matrices, used to replace the resected muscles, were able to generate functional artificial muscles by promoting host myogenic cell migration and differentiation, as well as nervous fibres, vascular networks, and satellite cell (SC) homing. However, acellular tissue mainly composed of extracellular matrix (ECM) allowed better myofibre three-dimensional (3D) organization and the restoration of SC pool, when compared to scaffolds which also preserved muscular cytoskeletal structures. Finally, we showed that fibroblasts are indispensable to promote efficient migration and myogenesis by muscle stem cells across the scaffolds in vitro. This data strongly support the use of xenogeneic acellular muscles as device to treat VML conditions in absence of donor cell implementation, as well as in vitro model for studying cell interplay during myogenesis.

Comprehensive joint feedback control for standing by functional neuromuscular stimulation-a simulation study.

PubMed

Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

2010-12-01

Previous investigations of feedback control of standing after spinal cord injury (SCI) using functional neuromuscular stimulation (FNS) have primarily targeted individual joints. This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint feedback control against postural disturbances using a bipedal, 3-D computer model of SCI stance. Proportional-derivative feedback drove an artificial neural network trained to produce muscle excitation patterns consistent with maximal joint stiffness values achievable about neutral stance given typical SCI muscle properties. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the baseline case of maximum constant muscle excitations used clinically, the controller reduced UE loading by 55% in resisting external force perturbations and by 84% during simulated one-arm functional tasks. Performance was most sensitive to inaccurate measurements of ankle plantar/dorsiflexion position and hip ab/adduction velocity feedback. In conclusion, comprehensive joint feedback demonstrates potential to markedly improve FNS standing function. However, alternative control structures capable of effective performance with fewer sensor-based feedback parameters may better facilitate clinical usage.

Comprehensive Joint Feedback Control for Standing by Functional Neuromuscular Stimulation – a Simulation Study

PubMed Central

Nataraj, Raviraj; Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.

2013-01-01

Previous investigations of feedback control of standing after spinal cord injury (SCI) using functional neuromuscular stimulation (FNS) have primarily targeted individual joints. This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint-feedback control against postural disturbances using a bipedal, three-dimensional computer model of SCI stance. Proportional-derivative feedback drove an artificial neural network trained to produce muscle excitation patterns consistent with maximal joint stiffness values achievable about neutral stance given typical SCI muscle properties. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the baseline case of maximum constant muscle excitations used clinically, the controller reduced UE loading by 55% in resisting external force perturbations and by 84% during simulated one-arm functional tasks. Performance was most sensitive to inaccurate measurements of ankle plantar/dorsiflexion position and hip ab/adduction velocity feedback. In conclusion, comprehensive joint-feedback demonstrates potential to markedly improve FNS standing function. However, alternative control structures capable of effective performance with fewer sensor-based feedback parameters may better facilitate clinical usage. PMID:20923741

Trend analysis of Trichinella in a red fox population from a low endemic area using a validated artificial digestion and sequential sieving technique.

PubMed

Franssen, Frits; Deksne, Gunita; Esíte, Zanda; Havelaar, Arie; Swart, Arno; van der Giessen, Joke

2014-11-28

Freezing of fox carcasses to minimize professional hazard of infection with Echinococcus multilocularis is recommended in endemic areas, but this could influence the detection of Trichinella larvae in the same host species. A method based on artificial digestion of frozen fox muscle, combined with larva isolation by a sequential sieving method (SSM), was validated using naturally infected foxes from Latvia. The validated SSM was used to detect dead Trichinella muscle larvae (ML) in frozen muscle samples of 369 red foxes from the Netherlands, of which one fox was positive (0.067 larvae per gram). This result was compared with historical Trichinella findings in Dutch red foxes. Molecular analysis using 5S PCR showed that both T. britovi and T. nativa were present in the Latvian foxes, without mixed infections. Of 96 non-frozen T. britovi ML, 94% was successfully sequenced, whereas this was the case for only 8.3% of 72 frozen T. britovi ML. The single Trichinella sp. larva that was recovered from the positive Dutch fox did not yield PCR product, probably due to severe freeze-damage. In conclusion, the SSM presented in this study is a fast and effective method to detect dead Trichinella larvae in frozen meat. We showed that the Trichinella prevalence in Dutch red fox was 0.27% (95% CI 0.065-1.5%), in contrast to 3.9% in the same study area fifteen years ago. Moreover, this study demonstrated that the efficacy of 5S PCR for identification of Trichinella britovi single larvae from frozen meat is not more than 8.3%.

Genome-wide detection of selection signatures in Chinese indigenous Laiwu pigs revealed candidate genes regulating fat deposition in muscle.

PubMed

Chen, Minhui; Wang, Jiying; Wang, Yanping; Wu, Ying; Fu, Jinluan; Liu, Jian-Feng

2018-05-18

Currently, genome-wide scans for positive selection signatures in commercial breed have been investigated. However, few studies have focused on selection footprints of indigenous breeds. Laiwu pig is an invaluable Chinese indigenous pig breed with extremely high proportion of intramuscular fat (IMF), and an excellent model to detect footprint as the result of natural and artificial selection for fat deposition in muscle. In this study, based on GeneSeek Genomic profiler Porcine HD data, three complementary methods, F ST , iHS (integrated haplotype homozygosity score) and CLR (composite likelihood ratio), were implemented to detect selection signatures in the whole genome of Laiwu pigs. Totally, 175 candidate selected regions were obtained by at least two of the three methods, which covered 43.75 Mb genomic regions and corresponded to 1.79% of the genome sequence. Gene annotation of the selected regions revealed a list of functionally important genes for feed intake and fat deposition, reproduction, and immune response. Especially, in accordance to the phenotypic features of Laiwu pigs, among the candidate genes, we identified several genes, NPY1R, NPY5R, PIK3R1 and JAKMIP1, involved in the actions of two sets of neurons, which are central regulators in maintaining the balance between food intake and energy expenditure. Our results identified a number of regions showing signatures of selection, as well as a list of functionally candidate genes with potential effect on phenotypic traits, especially fat deposition in muscle. Our findings provide insights into the mechanisms of artificial selection of fat deposition and further facilitate follow-up functional studies.

Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions.

PubMed

Mayfield, Dean L; Launikonis, Bradley S; Cresswell, Andrew G; Lichtwark, Glen A

2016-11-15

There are high mechanical demands placed on skeletal muscles in movements requiring rapid acceleration of the body or its limbs. Tendons are responsible for transmitting muscle forces, but, because of their elasticity, can manipulate the mechanics of the internal contractile apparatus. Shortening of the contractile apparatus against the stretch of tendon affects force generation according to known mechanical properties; however, the extent to which differences in tendon compliance alter force development in response to a burst of electrical impulses is unclear. To establish the influence of series compliance on force summation, we studied electrically evoked doublet contractions in the cane toad peroneus muscle in the presence and absence of a compliant artificial tendon. Additional series compliance reduced tetanic force by two-thirds, a finding predicted based on the force-length property of skeletal muscle. Doublet force and force-time integral expressed relative to the twitch were also reduced by additional series compliance. Active shortening over a larger range of the ascending limb of the force-length curve and at a higher velocity, leading to a progressive reduction in force-generating potential, could be responsible. Muscle-tendon interaction may also explain the accelerated time course of force relaxation in the presence of additional compliance. Our findings suggest that a compliant tendon limits force summation under constant-length conditions. However, high series compliance can be mechanically advantageous when a muscle-tendon unit is actively stretched, permitting muscle fibres to generate force almost isometrically, as shown during stretch-shorten cycles in locomotor activities. Restricting active shortening would likely favour rapid force development. © 2016. Published by The Company of Biologists Ltd.

Emergence of gamma motor activity in an artificial neural network model of the corticospinal system.

PubMed

Grandjean, Bernard; Maier, Marc A

2017-02-01

Muscle spindle discharge during active movement is a function of mechanical and neural parameters. Muscle length changes (and their derivatives) represent its primary mechanical, fusimotor drive its neural component. However, neither the action nor the function of fusimotor and in particular of γ-drive, have been clearly established, since γ-motor activity during voluntary, non-locomotor movements remains largely unknown. Here, using a computational approach, we explored whether γ-drive emerges in an artificial neural network model of the corticospinal system linked to a biomechanical antagonist wrist simulator. The wrist simulator included length-sensitive and γ-drive-dependent type Ia and type II muscle spindle activity. Network activity and connectivity were derived by a gradient descent algorithm to generate reciprocal, known target α-motor unit activity during wrist flexion-extension (F/E) movements. Two tasks were simulated: an alternating F/E task and a slow F/E tracking task. Emergence of γ-motor activity in the alternating F/E network was a function of α-motor unit drive: if muscle afferent (together with supraspinal) input was required for driving α-motor units, then γ-drive emerged in the form of α-γ coactivation, as predicted by empirical studies. In the slow F/E tracking network, γ-drive emerged in the form of α-γ dissociation and provided critical, bidirectional muscle afferent activity to the cortical network, containing known bidirectional target units. The model thus demonstrates the complementary aspects of spindle output and hence γ-drive: i) muscle spindle activity as a driving force of α-motor unit activity, and ii) afferent activity providing continuous sensory information, both of which crucially depend on γ-drive.

New continuous-flow total artificial heart and vascular permeability.

PubMed

Feng, Jun; Cohn, William E; Parnis, Steven M; Sodha, Neel R; Clements, Richard T; Sellke, Nicholas; Frazier, O Howard; Sellke, Frank W

2015-12-01

We tested the short-term effects of completely nonpulsatile versus pulsatile circulation after ventricular excision and replacement with total implantable pumps in an animal model on peripheral vascular permeability. Ten calves underwent cardiac replacement with two HeartMate III continuous-flow rotary pumps. In five calves, the pump speed was rapidly modulated to impart a low-frequency pulse pressure in the physiologic range (10-25 mm Hg) at a rate of 40 pulses per minute (PP). The remaining five calves were supported with a pulseless systemic circulation and no modulation of pump speed (NP). Skeletal muscle biopsies were obtained before cardiac replacement (baseline) and on postoperative days (PODs) 1, 7, and 14. Skeletal muscle-tissue water content was measured, and morphologic alterations of skeletal muscle were assessed. VE-cadherin, phospho-VE-cadherin, and CD31 were analyzed by immunohistochemistry. There were no significant changes in tissue water content and skeletal muscle morphology within group or between groups at baseline, PODs 1, 7, and 14, respectively. There were no significant alterations in the expression and/or distribution of VE-cadherin, phospho-VE-cadherin, and CD31 in skeletal muscle vasculature at baseline, PODs 1, 7, and 14 within each group or between the two groups, respectively. Although continuous-flow total artificial heart (CFTAH) with or without a pulse pressure caused slight increase in tissue water content and histologic damage scores at PODs 7 and 14, it failed to reach statistical significance. There was no significant adherens-junction protein degradation and phosphorylation in calf skeletal muscle microvasculature after CFTAH implantation, suggesting that short term of CFTAH with or without pulse pressure did not cause peripheral endothelial injury and did not increase the peripheral microvascular permeability. Copyright © 2015 Elsevier Inc. All rights reserved.

Development of an Underactuated 2-DOF Wrist Joint using McKibben PAMs

NASA Astrophysics Data System (ADS)

Rajagopal, S. P.; Jain, S.; Ramasubramanian, S. N.; Johnson, B. V.; Dwivedy, S. K.

2014-10-01

In this work, model of an underactuated 2-DOF wrist joint with pneumatically actuated muscles is proposed. For the joint, McKibben-type artificial muscles are used in parallel configuration for the actuation. For each Degree of Freedom (DOF) one agonist-antagonist pair arrangement is usually used with a pulley mechanism. A mathematical model of wrist joint is derived using conventional forward kinematic analysis. The static model relating pressure in the muscle with the orientation of the wrist joint is obtained by combining the experimental data and mathematical model. Regulation of pressure can be achieved by pulse width modulation control of on/off solenoid valves. A set of free vibration experiments are done for the dynamic identification of the muscle characteristics.

Identification of Differentially Expressed Genes and Pathways for Myofiber Characteristics in Soleus Muscles between Chicken Breeds Differing in Meat Quality.

PubMed

Du, Y F; Ding, Q L; Li, Y M; Fang, W R

2017-04-03

In the modern chicken industry, fast-growing broilers have undergone strong artificial selection for muscle growth, which has led to remarkable phenotypic variations compared with slow-growing chickens. However, the molecular mechanism underlying these phenotypes differences remains unknown. In this study, a systematic identification of candidate genes and new pathways related to myofiber development and composition in chicken Soleus muscle (SOL) has been made using gene expression profiles of two distinct breeds: Qingyuan partridge (QY), a slow-growing Chinese breed possessing high meat quality and Cobb 500 (CB), a commercial fast-growing broiler line. Agilent cDNA microarray analyses were conducted to determine gene expression profiles of soleus muscle sampled at sexual maturity age of QY (112 d) and CB (42 d). The 1318 genes with at least 2-fold differences were identified (P < 0.05, FDR <0.05, FC ≥ 2) in SOL muscles of QY and CB chickens. Differentially expressed genes (DEGs) related to muscle development, energy metabolism or lipid metabolism processes were examined further in each breed based on Gene Ontology (GO) analysis, and 11 genes involved in these processes were selected for further validation studies by qRT-PCR. In addition, based on KEGG pathway analysis of DEGs in both QY and CB chickens, it was found that in addition to pathways affecting myogenic fibre-type development and differentiation (pathways for Hedgehog & Calcium signaling), energy metabolism (Phosphatidylinositol signaling system, VEGF signaling pathway, Purine metabolism, Pyrimidine metabolism) were also enriched and might form a network with pathways related to muscle metabolism to influence the development of myofibers. This study is the first stage in the understanding of molecular mechanisms underlying variations in poultry meat quality. Large scale analyses are now required to validate the role of the genes identified and ultimately to find molecular markers that can be used for selection or to optimize rearing practices.

Electrically, chemically, and photonically powered torsional and tensile actuation of hybrid carbon nanotube yarn muscles.

PubMed

Lima, Márcio D; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M; Kozlov, Mikhail E; Haines, Carter S; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D; Fonseca, Alexandre F; Madden, John D W; Voit, Walter E; Galvão, Douglas S; Baughman, Ray H

2012-11-16

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles

NASA Astrophysics Data System (ADS)

Lima, Márcio D.; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M.; Kozlov, Mikhail E.; Haines, Carter S.; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D.; Fonseca, Alexandre F.; Madden, John D. W.; Voit, Walter E.; Galvão, Douglas S.; Baughman, Ray H.

2012-11-01

Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

Musclelike joint mechanism driven by dielectric elastomer actuator for robotic applications

NASA Astrophysics Data System (ADS)

Jung, Ho Sang; Cho, Kyeong Ho; Park, Jae Hyeong; Yang, Sang Yul; Kim, Youngeun; Kim, Kihyeon; Nguyen, Canh Toan; Phung, Hoa; Tien Hoang, Phi; Moon, Hyungpil; Koo, Ja Choon; Ryeol Choi, Hyouk

2018-07-01

The purpose of this study is to develop an artificial muscle actuator suitable for robotic applications, and to demonstrate the feasibility of applying this actuator to an arm mechanism, and controlling it delicately and smoothly like a human being. To accomplish this, we perform the procedures that integrate the soft actuator, called the single body dielectric elastomer actuator, which is very flexible and capable of high speed operation, and the displacement amplification mechanism called the sliding filament joint mechanism, which mimics the sliding filament model of human muscles. In this paper, we describe the characteristics and control method of the actuation system that consists of actuator, mechanism, and embedded controller, and show the experimental results of the closed-loop position and static stiffness control of the robotic arm application. Finally, based on the results, we evaluate the performance of this application.

Harvesting electrical energy from torsional thermal actuation driven by natural convection.

PubMed

Kim, Shi Hyeong; Sim, Hyeon Jun; Hyeon, Jae Sang; Suh, Dongseok; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

2018-06-07

The development of practical, cost-effective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fluctuations provided by natural convection. This harvester uses coiled yarn artificial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfibers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fluctuations in a yarn muscle, having a maximum hot-to-cold temperature difference of about 13 °C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000 rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81 V and peak power of 4 W/kg, based on SMPU mass.

Synthetic Motors and Nanomachines.

NASA Astrophysics Data System (ADS)

Flood, Amar

2006-03-01

A bistable and palindromically-constituted [3]rotaxane incorporating two mechanically-mobile rings interlocked around a linear dumbbell component, has been designed to operate like the sarcomeres of skeletal muscle. Contraction and extension occurs when the inter-ring distance of the two rings switch, ideally, between 4.2 and 1.4 nm upon redox stimulation either chemically or electrochemically in the solution phase. When the mobile rings of these artificial molecular muscles are bound onto the tops of gold-coated, micron-scale cantilever beams, their controllable nanometer motions have a chance to be amplified along the long axis of each cantilever. It turns out that ˜6 billion of the self-assembled [3]rotaxanes can bend the cantilevers in a bistable manner concomitant with the cycled addition of redox agents. The extent of bending is commensurate with 10's of pN of force per [3]rotaxane. Recent studies on a set of ``single-shot'' control [2]rotaxanes have provided additional evidence for the origins of the force generation as it arises from a molecule-based electrostatic repulsion energy of about 10 kcal/mol at 300 K. These findings will be presented in terms of the underlying thermodynamics and kinetics that have been utilized extensively to direct the design and synthesis of artificial molecular machines and which may also serve as a guide for the rational design of unidirectional molecular motors.

Natural cellulose ionogels for soft artificial muscles.

PubMed

Nevstrueva, Daria; Murashko, Kirill; Vunder, Veiko; Aabloo, Alvo; Pihlajamäki, Arto; Mänttäri, Mika; Pyrhönen, Juha; Koiranen, Tuomas; Torop, Janno

2018-01-01

Rapid development of soft micromanipulation techniques for human friendly electronics has raised the demand for the devices to be able to carry out mechanical work on a micro- and macroscale. The natural cellulose-based ionogels (CEL-iGEL) hold a great potential for soft artificial muscle application, due to its flexibility, low driving voltage and biocompatibility. The CEL-iGEL composites undergo reversible bending already at ±500mV step-voltage values. A fast response to the voltage applied and high ionic conductivity of membranous actuator is achieved by a complete dissolution of cellulose in 1-ethyl-3-methylimidazolium acetate [EMIm][OAc]. The CEL-iGEL supported cellulose actuator films were cast out of cellulose-[EMIm][OAc] solution via phase inversion in H 2 O. The facile preparation method ensured uniform morphology along the layers and stand for the high ionic-liquid loading in a porous cellulose scaffold. During the electromechanical characterization, the CEL-iGEL actuators showed exponential dependence to the voltage applied with the max strain difference values reaching up to 0.6% at 2 V. Electrochemical analysis confirmed the good stability of CEL-iGEL actuators and determined the safe working voltage value to be below 2.5V. To predict and estimate the deformation for various step input voltages, a mathematical model was proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

A preliminary survey of Trichinella spp. in pigs raised under controlled housing conditions in Colombia: 2014–2016

PubMed Central

Chaparro-Gutiérrez, Jenny J.; Pozio, Edoardo; Gómez-Morales, María A.; López, Anderson; Mejia, Jaime; Zambrano, Corina; Piedrahita, Diego; Villar, David

2018-01-01

A preliminary survey of Trichinella spp. infection was conducted in Colombian swine herds between 2014 and 2016. A total of 1,773 pigs reared on farms under controlled housing conditions and processed in 34 slaughterhouses were tested either by the artificial digestion of pooled muscle samples (n = 1,173) or by serology (n = 600). In addition, 550 rats trapped on 29 swine farm premises were also tested by artificial digestion. No positive pig samples were detected. Similarly, no Trichinella spp. muscle larvae were detected in rats. These results are in agreement with the lack of historical Trichinella infection reports in domestic and wild animals and humans in Colombia. However, a more extensive epidemiological investigation and a continuous surveillance program are needed to continue declaring swine herds in Colombia free of Trichinella infection. PMID:29633706

Polydopamine-Coated Main-Chain Liquid Crystal Elastomer as Optically Driven Artificial Muscle.

PubMed

Tian, Hongmiao; Wang, Zhijian; Chen, Yilong; Shao, Jinyou; Gao, Tong; Cai, Shengqiang

2018-03-07

Optically driven active materials have received much attention because their deformation and motion can be controlled remotely, instantly, and precisely in a contactless way. In this study, we investigated an optically actuated elastomer with rapid response: polydopamine (PDA)-coated liquid crystal elastomer (LCE). Because of the photothermal effect of PDA coating and thermal responsiveness of LCE, the elastomer film contracted significantly with near-infrared (NIR) irradiation. With a fixed strain, light-induced actuating stress in the film could be as large as 1.5 MPa, significantly higher than the maximum stress generated by most mammalian skeletal muscle (0.35 MPa). The PDA-coated LCE films could also bend or roll up by surface scanning of an NIR laser. The response time of the film to light exposure could be as short as 1/10 of a second, comparable to or even faster than that of mammalian skeletal muscle. Using the PDA-coated LCE film, we designed and fabricated a prototype of robotic swimmer that was able to swim near the water-air interface by performing "swimming strokes" through reversible bending and unbending motions induced and controlled by an NIR laser. The results presented in this study clearly demonstrated that PDA-coated LCE is a promising optically driven artificial muscle, which may have great potential for applications of soft robotics and optomechanical coupling devices.

Multiple sequence alignment using multi-objective based bacterial foraging optimization algorithm.

PubMed

Rani, R Ranjani; Ramyachitra, D

2016-12-01

Multiple sequence alignment (MSA) is a widespread approach in computational biology and bioinformatics. MSA deals with how the sequences of nucleotides and amino acids are sequenced with possible alignment and minimum number of gaps between them, which directs to the functional, evolutionary and structural relationships among the sequences. Still the computation of MSA is a challenging task to provide an efficient accuracy and statistically significant results of alignments. In this work, the Bacterial Foraging Optimization Algorithm was employed to align the biological sequences which resulted in a non-dominated optimal solution. It employs Multi-objective, such as: Maximization of Similarity, Non-gap percentage, Conserved blocks and Minimization of gap penalty. BAliBASE 3.0 benchmark database was utilized to examine the proposed algorithm against other methods In this paper, two algorithms have been proposed: Hybrid Genetic Algorithm with Artificial Bee Colony (GA-ABC) and Bacterial Foraging Optimization Algorithm. It was found that Hybrid Genetic Algorithm with Artificial Bee Colony performed better than the existing optimization algorithms. But still the conserved blocks were not obtained using GA-ABC. Then BFO was used for the alignment and the conserved blocks were obtained. The proposed Multi-Objective Bacterial Foraging Optimization Algorithm (MO-BFO) was compared with widely used MSA methods Clustal Omega, Kalign, MUSCLE, MAFFT, Genetic Algorithm (GA), Ant Colony Optimization (ACO), Artificial Bee Colony (ABC), Particle Swarm Optimization (PSO) and Hybrid Genetic Algorithm with Artificial Bee Colony (GA-ABC). The final results show that the proposed MO-BFO algorithm yields better alignment than most widely used methods. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Genetic evidence in the mouse solidifies the calcium hypothesis of myofiber death in muscular dystrophy

PubMed Central

Burr, A R; Molkentin, J D

2015-01-01

Muscular dystrophy (MD) refers to a clinically and genetically heterogeneous group of degenerative muscle disorders characterized by progressive muscle wasting and often premature death. Although the primary defect underlying most forms of MD typically results from a loss of sarcolemmal integrity, the secondary molecular mechanisms leading to muscle degeneration and myofiber necrosis is debated. One hypothesis suggests that elevated or dysregulated cytosolic calcium is the common transducing event, resulting in myofiber necrosis in MD. Previous measurements of resting calcium levels in myofibers from dystrophic animal models or humans produced equivocal results. However, recent studies in genetically altered mouse models have largely solidified the calcium hypothesis of MD, such that models with artificially elevated calcium in skeletal muscle manifest fulminant dystrophic-like disease, whereas models with enhanced calcium clearance or inhibited calcium influx are resistant to myofiber death and MD. Here, we will review the field and the recent cadre of data from genetically altered mouse models, which we propose have collectively mostly proven the hypothesis that calcium is the primary effector of myofiber necrosis in MD. This new consensus on calcium should guide future selection of drugs to be evaluated in clinical trials as well as gene therapy-based approaches. PMID:26088163

Contraction Sensing with Smart Braid McKibben Muscles

PubMed Central

Felt, Wyatt; Chin, Khai Yi; Remy, C. David

2016-01-01

The inherent compliance of soft fluidic actuators makes them attractive for use in wearable devices and soft robotics. Their flexible nature permits them to be used without traditional rotational or prismatic joints. Without these joints, however, measuring the motion of the actuators is challenging. Actuator-level sensors could improve the performance of continuum robots and robots with compliant or multi-degree-of-freedom joints. We make the reinforcing braid of a pneumatic artificial muscle (PAM or McKibben muscle) “smart” by weaving it from conductive, insulated wires. These wires form a solenoid-like circuit with an inductance that more than doubles over the PAM contraction. The reinforcing and sensing fibers can be used to measure the contraction of a PAM actuator with a simple, linear function of the measured inductance. Whereas other proposed self-sensing techniques rely on the addition of special elastomers or transducers, the technique presented in this work can be implemented without modifications of this kind. We present and experimentally validate two models for Smart Braid sensors based on the long solenoid approximation and the Neumann formula, respectively. We test a McKibben muscle made from a Smart Braid in quasistatic conditions with various end-loads and in dynamic conditions. We also test the performance of the Smart Braid sensor alongside steel. PMID:28503062

Reversible immortalisation enables genetic correction of human muscle progenitors and engineering of next-generation human artificial chromosomes for Duchenne muscular dystrophy.

PubMed

Benedetti, Sara; Uno, Narumi; Hoshiya, Hidetoshi; Ragazzi, Martina; Ferrari, Giulia; Kazuki, Yasuhiro; Moyle, Louise Anne; Tonlorenzi, Rossana; Lombardo, Angelo; Chaouch, Soraya; Mouly, Vincent; Moore, Marc; Popplewell, Linda; Kazuki, Kanako; Katoh, Motonobu; Naldini, Luigi; Dickson, George; Messina, Graziella; Oshimura, Mitsuo; Cossu, Giulio; Tedesco, Francesco Saverio

2018-02-01

Transferring large or multiple genes into primary human stem/progenitor cells is challenged by restrictions in vector capacity, and this hurdle limits the success of gene therapy. A paradigm is Duchenne muscular dystrophy (DMD), an incurable disorder caused by mutations in the largest human gene: dystrophin. The combination of large-capacity vectors, such as human artificial chromosomes (HACs), with stem/progenitor cells may overcome this limitation. We previously reported amelioration of the dystrophic phenotype in mice transplanted with murine muscle progenitors containing a HAC with the entire dystrophin locus (DYS-HAC). However, translation of this strategy to human muscle progenitors requires extension of their proliferative potential to withstand clonal cell expansion after HAC transfer. Here, we show that reversible cell immortalisation mediated by lentivirally delivered excisable hTERT and Bmi1 transgenes extended cell proliferation, enabling transfer of a novel DYS-HAC into DMD satellite cell-derived myoblasts and perivascular cell-derived mesoangioblasts. Genetically corrected cells maintained a stable karyotype, did not undergo tumorigenic transformation and retained their migration ability. Cells remained myogenic in vitro (spontaneously or upon MyoD induction) and engrafted murine skeletal muscle upon transplantation. Finally, we combined the aforementioned functions into a next-generation HAC capable of delivering reversible immortalisation, complete genetic correction, additional dystrophin expression, inducible differentiation and controllable cell death. This work establishes a novel platform for complex gene transfer into clinically relevant human muscle progenitors for DMD gene therapy. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

A bioinspired flexible organic artificial afferent nerve

NASA Astrophysics Data System (ADS)

Kim, Yeongin; Chortos, Alex; Xu, Wentao; Liu, Yuxin; Oh, Jin Young; Son, Donghee; Kang, Jiheong; Foudeh, Amir M.; Zhu, Chenxin; Lee, Yeongjun; Niu, Simiao; Liu, Jia; Pfattner, Raphael; Bao, Zhenan; Lee, Tae-Woo

2018-06-01

The distributed network of receptors, neurons, and synapses in the somatosensory system efficiently processes complex tactile information. We used flexible organic electronics to mimic the functions of a sensory nerve. Our artificial afferent nerve collects pressure information (1 to 80 kilopascals) from clusters of pressure sensors, converts the pressure information into action potentials (0 to 100 hertz) by using ring oscillators, and integrates the action potentials from multiple ring oscillators with a synaptic transistor. Biomimetic hierarchical structures can detect movement of an object, combine simultaneous pressure inputs, and distinguish braille characters. Furthermore, we connected our artificial afferent nerve to motor nerves to construct a hybrid bioelectronic reflex arc to actuate muscles. Our system has potential applications in neurorobotics and neuroprosthetics.

Adaptive force regulation of muscle strengthening rehabilitation device with magnetorheological fluids.

PubMed

Dong, Shufang; Lu, Ke-Qian; Sun, Jian Qiao; Rudolph, Katherine

2006-03-01

In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based on the lowest level of torque that is produced by a muscle group. Resistance that varies with joint angle can be achieved with isokinetic devices in which angular velocity is held constant and variable torque is generated when the patient attempts to move faster than the device but are ineffective if a patient cannot generate torque rapidly. In this paper, we report the development of a versatile rehabilitation device that can be used to strengthen different muscle groups based on the torque generating capability of the muscle that changes with joint angle. The device is low cost, is smaller than other commercially available machines, and can be programmed to apply resistance that is unique to a particular patient and that will optimize strengthening. The core of the device, a damper with smart magnetorheological fluids, provides passive exercise force. A digital adaptive control is capable of regulating exercise force precisely following the muscle strengthening profile prescribed by a physical therapist. The device could be programmed with artificial intelligence to dynamically adjust the target force profile to optimize rehabilitation effects. The device provides both isometric and isokinetic strength training and can be developed into a small, low-cost device that may be capable of providing optimal strengthening in the home.

Origami-inspired active graphene-based paper for programmable instant self-folding walking devices.

PubMed

Mu, Jiuke; Hou, Chengyi; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong; Zhu, Meifang

2015-11-01

Origami-inspired active graphene-based paper with programmed gradients in vertical and lateral directions is developed to address many of the limitations of polymer active materials including slow response and violent operation methods. Specifically, we used function-designed graphene oxide as nanoscale building blocks to fabricate an all-graphene self-folding paper that has a single-component gradient structure. A functional device composed of this graphene paper can (i) adopt predesigned shapes, (ii) walk, and (iii) turn a corner. These processes can be remote-controlled by gentle light or heating. We believe that this self-folding material holds potential for a wide range of applications such as sensing, artificial muscles, and robotics.

Experimental reconstruction of cervical esophageal defect with artificial esophagus made of polyurethane in a dog model.

PubMed

Jiang, H; Cui, Y; Ma, K; Gong, M; Chang, D; Wang, T

2016-01-01

The defect of esophagus after surgical excision in patients is usually replaced by autologous stomach, jejunum, or colon. The operation brings severe trauma and complications. Using artificial esophagus to replace the defect in situ can reduce the operative trauma, simplify the operative procedures, and decrease the influence to digestive function. A variety of experiments have been designed for developing a practical artificial esophagus. Nevertheless, a safe and reliable artificial esophagus is not yet available. The objective is to evaluate the possibility of the artificial esophagus made of non-degradable polyurethane materials being used in reconstruction of the segmental defect of cervical esophagus in beagles, observe the regeneration of esophageal tissue, and gather experience for future study. The cervical esophageal defects in 13 beagles were designed to 2-cm long and were constructed by the artificial esophagus made of non-degradable polyurethane materials. Nutrition supports were given after the operation. The operative mortality, anastomotic leakage, migration of artificial esophagus, and dysphagia were followed up. The regeneration of the esophageal tissues was evaluated by histopathology and immunohistochemical labeled streptavidin-biotin method. The surgical procedures were successfully completed in all beagles, and 12-month follow-ups were done. Only one beagle died of severe infection, and all others survived until being killed. The anastomotic leakage occurred in nine beagles, most of them (8/9) were cured after supportive therapy. The migration of artificial esophagus occurred in all 12 surviving beagles, and one artificial esophagus stayed in situ after migration. All 12 surviving beagles showed dysphagia with taking only fluid or soft food. No beagle died of malnutrition. The neo-esophagus was composed of granulation tissue, and the inner surface was covered by epithelium in 2-3 months completely. But the inner surface of neo-esophagus with artificial esophagus staying in situ after migration was not covered by epithelium, and the granulation tissue was infiltrated by a great deal of inflammatory cells. Antibodies against cytokeratin were positively expressed in epithelium of neo-esophagus. Up to 12 months after operation, antibodies against smooth muscle actin and desmin were both negatively expressed in neo-esophagus. The artificial esophagus made of non-degradable polyurethane reconstructing cervical esophageal defect is practicable. Although there are some problems, including anastomotic leakage, migration, and dysphagia, they are not lethal following good supportive therapy. The esophageal epithelium can regenerate with the supporting role of artificial esophagus. In the future, deformable artificial esophagus should be improved, and a much longer follow-up will be performed to evaluate whether the esophageal gland and skeletal muscle can regenerate. © 2014 International Society for Diseases of the Esophagus.

Ligand-induced rapid skeletal muscle atrophy in HSA-Fv2E-PERK transgenic mice.

PubMed

Miyake, Masato; Kuroda, Masashi; Kiyonari, Hiroshi; Takehana, Kenji; Hisanaga, Satoshi; Morimoto, Masatoshi; Zhang, Jun; Oyadomari, Miho; Sakaue, Hiroshi; Oyadomari, Seiichi

2017-01-01

Formation of 43S and 48S preinitiation complexes plays an important role in muscle protein synthesis. There is no muscle-wasting mouse model caused by a repressed 43S preinitiation complex assembly. The aim of the present study was to develop a convenient mouse model of skeletal muscle wasting with repressed 43S preinitiation complex assembly. A ligand-activatable PERK derivative Fv2E-PERK causes the phosphorylation of eukaryotic initiation factor 2α (eIF2α), which inhibits 43S preinitiation complex assembly. Thus, muscle atrophic phenotypes, intracellular signaling pathways, and intracellular free amino acid profiles were investigated in human skeletal muscle α-actin (HSA) promoter-driven Fv2E-PERK transgenic (Tg) mice. HSA-Fv2E-PERK Tg mice treated with the artificial dimerizer AP20187 phosphorylates eIF2α in skeletal muscles and leads to severe muscle atrophy within a few days of ligand injection. Muscle atrophy was accompanied by a counter regulatory activation of mTORC1 signaling. Moreover, intracellular free amino acid levels were distinctively altered in the skeletal muscles of HSA-Fv2E-PERK Tg mice. As a novel model of muscle wasting, HSA-Fv2E-PERK Tg mice provide a convenient tool for studying the pathogenesis of muscle loss and for assessing putative therapeutics.

Insights into skeletal muscle development and applications in regenerative medicine.

PubMed

Tran, T; Andersen, R; Sherman, S P; Pyle, A D

2013-01-01

Embryonic and postnatal development of skeletal muscle entails highly regulated processes whose complexity continues to be deconstructed. One key stage of development is the satellite cell, whose niche is composed of multiple cell types that eventually contribute to terminally differentiated myotubes. Understanding these developmental processes will ultimately facilitate treatments of myopathies such as Duchenne muscular dystrophy (DMD), a disease characterized by compromised cell membrane structure, resulting in severe muscle wasting. One theoretical approach is to use pluripotent stem cells in a therapeutic setting to help replace degenerated muscle tissue. This chapter discusses key myogenic developmental stages and their regulatory pathways; artificial myogenic induction in pluripotent stem cells; advantages and disadvantages of DMD animal models; and therapeutic approaches targeting DMD. Furthermore, skeletal muscle serves as an excellent paradigm for understanding general cell fate decisions throughout development. Copyright © 2013 Elsevier Inc. All rights reserved.

Synthetic muscle promoters: activities exceeding naturally occurring regulatory sequences

NASA Technical Reports Server (NTRS)

Li, X.; Eastman, E. M.; Schwartz, R. J.; Draghia-Akli, R.

1999-01-01

Relatively low levels of expression from naturally occurring promoters have limited the use of muscle as a gene therapy target. Myogenic restricted gene promoters display complex organization usually involving combinations of several myogenic regulatory elements. By random assembly of E-box, MEF-2, TEF-1, and SRE sites into synthetic promoter recombinant libraries, and screening of hundreds of individual clones for transcriptional activity in vitro and in vivo, several artificial promoters were isolated whose transcriptional potencies greatly exceed those of natural myogenic and viral gene promoters.

Computational Modeling of Electrochemical-Poroelastic Bending Behaviors of Conducting Polymer (PPy) Membranes

NASA Astrophysics Data System (ADS)

Toi, Yutaka; Jung, Woosang

The electrochemical-poroelastic bending behavior of conducting polymer actuators has an attractive feature, considering their potential applications such as artificial muscles or MEMS. In the present study, a computational modeling is presented for the bending behavior of polypyrrole-based actuators. The one-dimensional governing equation for the ionic transportation in electrolytes given by Tadokoro et al. is combined with the finite element modeling for the poroelastic behavior of polypyrroles considering the effect of finite deformation. The validity of the proposed model has been illustrated by comparing the computed results with the experimental results in the literatures.

Sliding mode control for a two-joint coupling nonlinear system based on extended state observer.

PubMed

Zhao, Ling; Cheng, Haiyan; Wang, Tao

2018-02-01

A two-joint coupling nonlinear system driven by pneumatic artificial muscles is introduced in this paper. A sliding mode controller with extended state observer is proposed to cope with nonlinearities and disturbances for the two-joint coupling nonlinear system. In addition, convergence of the extended state observer is presented and stability analysis of the closed-loop system is also demonstrated with the sliding mode controller. Lastly, some experiments are carried out to show the reality effectiveness of the proposed method. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Induction of functional tissue-engineered skeletal muscle constructs by defined electrical stimulation.

PubMed

Ito, Akira; Yamamoto, Yasunori; Sato, Masanori; Ikeda, Kazushi; Yamamoto, Masahiro; Fujita, Hideaki; Nagamori, Eiji; Kawabe, Yoshinori; Kamihira, Masamichi

2014-04-24

Electrical impulses are necessary for proper in vivo skeletal muscle development. To fabricate functional skeletal muscle tissues in vitro, recapitulation of the in vivo niche, including physical stimuli, is crucial. Here, we report a technique to engineer skeletal muscle tissues in vitro by electrical pulse stimulation (EPS). Electrically excitable tissue-engineered skeletal muscle constructs were stimulated with continuous electrical pulses of 0.3 V/mm amplitude, 4 ms width, and 1 Hz frequency, resulting in a 4.5-fold increase in force at day 14. In myogenic differentiation culture, the percentage of peak twitch force (%Pt) was determined as the load on the tissue constructs during the artificial exercise induced by continuous EPS. We optimized the stimulation protocol, wherein the tissues were first subjected to 24.5%Pt, which was increased to 50-60%Pt as the tissues developed. This technique may be a useful approach to fabricate tissue-engineered functional skeletal muscle constructs.

Control of abdominal and expiratory intercostal muscle activity during vomiting - Role of ventral respiratory group expiratory neurons

NASA Technical Reports Server (NTRS)

Miller, Alan D.; Tan, L. K.; Suzuki, Ichiro

1987-01-01

The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal muscle activity during vomiting was investigated in cats. Two series of experiments were performed: in one, the activity of VRG E neurons was recorded during fictive vomiting in cats that were decerebrated, paralyzed, and artificially ventilated; in the second, the abdominal muscle activity during vomiting was compared before and after sectioning the axons of descending VRG E neurons in decerebrate spontaneously breathing cats. The results show that about two-thirds of VRG E neurons that project at least as far caudally as the lower thoracic cord contribute to internal intercostal muscle activity during vomiting. The remaining VRG E neurons contribute to abdominal muscle activation. As shown by severing the axons of the VRG E neurons, other, as yet unidenified, inputs (either descending from the brain stem or arising from spinal reflexes) can also produce abdominal muscle activation.

Functional tooth restoration by next-generation bio-hybrid implant as a bio-hybrid artificial organ replacement therapy

PubMed Central

Oshima, Masamitsu; Inoue, Kaoru; Nakajima, Kei; Tachikawa, Tetsuhiko; Yamazaki, Hiromichi; Isobe, Tomohide; Sugawara, Ayaka; Ogawa, Miho; Tanaka, Chie; Saito, Masahiro; Kasugai, Shohei; Takano-Yamamoto, Teruko; Inoue, Takashi; Tezuka, Katsunari; Kuboki, Takuo; Yamaguchi, Akira; Tsuji, Takashi

2014-01-01

Bio-hybrid artificial organs are an attractive concept to restore organ function through precise biological cooperation with surrounding tissues in vivo. However, in bio-hybrid artificial organs, an artificial organ with fibrous connective tissues, including muscles, tendons and ligaments, has not been developed. Here, we have enveloped with embryonic dental follicle tissue around a HA-coated dental implant, and transplanted into the lower first molar region of a murine tooth-loss model. We successfully developed a novel fibrous connected tooth implant using a HA-coated dental implant and dental follicle stem cells as a bio-hybrid organ. This bio-hybrid implant restored physiological functions, including bone remodelling, regeneration of severe bone-defect and responsiveness to noxious stimuli, through regeneration with periodontal tissues, such as periodontal ligament and cementum. Thus, this study represents the potential for a next-generation bio-hybrid implant for tooth loss as a future bio-hybrid artificial organ replacement therapy. PMID:25116435

EAP as artificial muscles - progress and challenges

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2004-01-01

During the last decade and a half new polymers have emerged that respond to electrical stimulation with a significant shape or size change. This capability of electroactive polymer (EAP) materials is attracting the attention of engineers and scientists from many different disciplines.

Effects of prolonged space flight on rat skeletal muscle.

PubMed

Nesterov, V P; Zheludkova, Z P; Kuznetsova, L A

1979-10-01

The effect of a 20-day space flight on water, Na+, K+, Mg2+, Ca2+ and glycogen contents as well as on activities of glycogen metabolism enzymes--glycogen synthetase and glycogen phosphorylase--of rat skeletal muscles was studied. This data is regarded as an integral test characterizing the state of contractile tissue of the animals at the final stage of flight aboard biosatellites. The measurements indicate that there were no significant changes of cations and glycogen contents nor of the enzymic activities in fast-twitch muscles during the 20-day spaceflight. At the same time dehydration in these muscles was observed, which disappeared on the 25th postflight day. In slow-twitch antigravitational skeletal muscle (m. soleus) there was a decrease of K+ and increase of Na+ in the tissue contents. The changes disappeared at the end of the on-earth readaptation period. From the pattern of these observations, we can conclude that the 20-day space flight leads to some reversible biochemical changes of the rat skeletal muscles. A conclusion can be drawn about necessity of creating, aboard the spaceship, an artificial load on antigravitational skeletal muscles.

iGrab: hand orthosis powered by twisted and coiled polymer muscles

NASA Astrophysics Data System (ADS)

Saharan, Lokesh; de Andrade, Monica Jung; Saleem, Wahaj; Baughman, Ray H.; Tadesse, Yonas

2017-10-01

Several works have been reported in powered hand orthosis in the last ten years for assistive or rehabilitative purposes. However, most of these approaches uses conventional actuators such as servo motors to power orthosis. In this work, we demonstrate the recently reported twisted and coiled polymeric (TCP) muscles to drive a compact, light, inexpensive and wearable upper extremity device, iGrab. A 3D printed orthotic hand module was designed, developed and tested for the performance. The device has six 2-ply muscles of diameter 1.35 mm with a length of 380 mm. We used a single 2-ply muscle for each finger and two 2-ply muscles for the thumb. Pulsed actuation of the muscles at 1.8 A current for 25 s with 7% duty cycle under natural cooling showed full flexion of the fingers within 2 s. Modeling and simulation were performed on the device using standard Euler-Lagrangian equations. Our artificial muscles powered hand orthosis demonstrated the capability of pinching and picking objects of different shapes, weights, and sizes.

Modeling the benefits of an artificial gravity countermeasure coupled with exercise and vibration

NASA Astrophysics Data System (ADS)

Goel, Rahul; Kaderka, Justin; Newman, Dava

2012-01-01

The current, system-specific countermeasures to space deconditioning have limited success with the musculoskeletal system in long duration missions. Artificial gravity (AG) that is produced by short radius centrifugation has been hypothesized as an effective countermeasure because it reintroduces an acceleration field in space; however, AG alone might not be enough stimuli to preserve the musculoskeletal system. A novel combination of AG coupled with one-legged squats on a vibrating platform may preserve muscle and bone in the lower limbs to a greater extent than the current exercise paradigm. The benefits of the proposed countermeasure have been analyzed through the development of a simulation platform. Ground reaction force data and motion data were collected using a motion capture system while performing one-legged and two-legged squats in 1-G. The motion was modeled in OpenSim, an open-source software, and inverse dynamics were applied in order to determine the muscle and reaction forces of lower limb joints. Vibration stimulus was modeled by adding a 20 Hz sinusoidal force of 0.5 body weight to the force plate data. From the numerical model in a 1-G acceleration field, muscle forces for quadriceps femoris, plantar flexors and glutei increased substantially for one-legged squats with vibration compared to one- or two-legged squats without vibration. Additionally, joint reaction forces for one-legged squats with vibration also increased significantly compared to two-legged squats with or without vibration. Higher muscle forces and joint reaction forces might help to stimulate muscle activation and bone modeling and thus might reduce musculoskeletal deconditioning. These results indicate that the proposed countermeasure might surpass the performance of the current space countermeasures and should be further studied as a method of mitigating musculoskeletal deconditioning.

Classification of dry-cured hams according to the maturation time using near infrared spectra and artificial neural networks.

PubMed

Prevolnik, M; Andronikov, D; Žlender, B; Font-i-Furnols, M; Novič, M; Škorjanc, D; Čandek-Potokar, M

2014-01-01

An attempt to classify dry-cured hams according to the maturation time on the basis of near infrared (NIR) spectra was studied. The study comprised 128 samples of biceps femoris (BF) muscle from dry-cured hams matured for 10 (n=32), 12 (n=32), 14 (n=32) or 16 months (n=32). Samples were minced and scanned in the wavelength range from 400 to 2500 nm using spectrometer NIR System model 6500 (Silver Spring, MD, USA). Spectral data were used for i) splitting of samples into the training and test set using 2D Kohonen artificial neural networks (ANN) and for ii) construction of classification models using counter-propagation ANN (CP-ANN). Different models were tested, and the one selected was based on the lowest percentage of misclassified test samples (external validation). Overall correctness of the classification was 79.7%, which demonstrates practical relevance of using NIR spectroscopy and ANN for dry-cured ham processing control. Copyright © 2013 Elsevier Ltd. All rights reserved.

Correlation- and covariance-supported normalization method for estimating orthodontic trainer treatment for clenching activity.

PubMed

Akdenur, B; Okkesum, S; Kara, S; Günes, S

2009-11-01

In this study, electromyography signals sampled from children undergoing orthodontic treatment were used to estimate the effect of an orthodontic trainer on the anterior temporal muscle. A novel data normalization method, called the correlation- and covariance-supported normalization method (CCSNM), based on correlation and covariance between features in a data set, is proposed to provide predictive guidance to the orthodontic technique. The method was tested in two stages: first, data normalization using the CCSNM; second, prediction of normalized values of anterior temporal muscles using an artificial neural network (ANN) with a Levenberg-Marquardt learning algorithm. The data set consists of electromyography signals from right anterior temporal muscles, recorded from 20 children aged 8-13 years with class II malocclusion. The signals were recorded at the start and end of a 6-month treatment. In order to train and test the ANN, two-fold cross-validation was used. The CCSNM was compared with four normalization methods: minimum-maximum normalization, z score, decimal scaling, and line base normalization. In order to demonstrate the performance of the proposed method, prevalent performance-measuring methods, and the mean square error and mean absolute error as mathematical methods, the statistical relation factor R2 and the average deviation have been examined. The results show that the CCSNM was the best normalization method among other normalization methods for estimating the effect of the trainer.

Finding NEMO (novel electromaterial muscle oscillator): a polypyrrole powered robotic fish with real-time wireless speed and directional control

NASA Astrophysics Data System (ADS)

McGovern, Scott; Alici, Gursel; Truong, Van-Tan; Spinks, Geoffrey

2009-09-01

This paper presents the development of an autonomously powered and controlled robotic fish that incorporates an active flexural joint tail fin, activated through conducting polymer actuators based on polypyrrole (PPy). The novel electromaterial muscle oscillator (NEMO) tail fin assembly on the fish could be controlled wirelessly in real time by varying the frequency and duty cycle of the voltage signal supplied to the PPy bending-type actuators. Directional control was achieved by altering the duty cycle of the voltage input to the NEMO tail fin, which shifted the axis of oscillation and enabled turning of the robotic fish. At low speeds, the robotic fish had a turning circle as small as 15 cm (or 1.1 body lengths) in radius. The highest speed of the fish robot was estimated to be approximately 33 mm s-1 (or 0.25 body lengths s-1) and was achieved with a flapping frequency of 0.6-0.8 Hz which also corresponded with the most hydrodynamically efficient mode for tail fin operation. This speed is approximately ten times faster than those for any previously reported artificial muscle based device that also offers real-time speed and directional control. This study contributes to previously published studies on bio-inspired functional devices, demonstrating that electroactive polymer actuators can be real alternatives to conventional means of actuation such as electric motors.

Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target.

PubMed

Domkin, Dmitry; Forsman, Mikael; Richter, Hans O

2016-06-01

Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N=11) tracked a moving visual target with a digital pen on a computer screen. Tracking performance, eye refraction and trapezius muscle activity were continuously measured. Ciliary muscle contraction force was computed from eye accommodative response. There was a significant Pearson correlation between ciliary muscle contraction force and trapezius muscle activity on the tracking side (0.78, p<0.01) and passive side (0.64, p<0.05). The study supports the hypothesis that high visual demands, leading to an increased ciliary muscle contraction during continuous eye-hand coordination, may increase trapezius muscle tension and thus contribute to the development of musculoskeletal complaints in the neck-shoulder area. Further experimental studies are required to clarify whether the relationship is valid within each individual or may represent a general personal trait, when individuals with higher eye accommodative response tend to have higher trapezius muscle activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

An investigation of fatigue phenomenon in the upper limb muscle due to short duration pulses in an FES system

NASA Astrophysics Data System (ADS)

Naeem, Jannatul; Wong Azman, Amelia; Khan, Sheroz; Mohd Mustafah, Yasir

2013-12-01

Functional Electrical Stimulation (FES) is a method of artificially stimulating muscles or nerves in order to result in contraction or relaxation of muscles. Many studies have shown that FES system has helped patients to live a better lives especially those who are suffering from physical mobility. Unfortunately, one of the main limitations of an FES system besides of its high cost is largely due to muscle fatigue. Muscle fatigue will affect the training duration which could delay patients' recovery rate. In this paper, we analyzed the occurrence of this fatigue phenomenon in terms of stimulator parameters such as amplitude, frequency, pulse width and pulse shape. The objective of this investigation is to identify other key features of the FES system parameters in order to prolong the training duration among patients. The experiment has been done on a healthy person for the duration of one minute and later the muscles response will be observed. Resultant muscle response is recorded as force using force resistive sensor. The experimental results show muscles will get fatigue at a different rate as the frequency increases. The experiment also shows that the duty cycle is reciprocal to the resultant force.

Artificial muscles with adjustable stiffness

NASA Astrophysics Data System (ADS)

Mutlu, Rahim; Alici, Gursel

2010-04-01

This paper reports on a stiffness enhancement methodology based on using a suitably designed contact surface with which cantilevered-type conducting polymer bending actuators are in contact during operation. The contact surface constrains the bending behaviour of the actuators. Depending on the topology of the contact surface, the resistance of the polymer actuators to deformation, i.e. stiffness, is varied. As opposed to their predecessors, these polymer actuators operate in air. Finite element analysis and modelling are used to quantify the effect of the contact surface on the effective stiffness of a trilayer cantilevered beam, which represents a one-end-free, the-other-end-fixed polypyrrole (PPy) conducting polymer actuator under a uniformly distributed load. After demonstrating the feasibility of the adjustable stiffness concept, experiments were conducted to determine the stiffness of bending-type conducting polymer actuators in contact with a range (20-40 mm in radius) of circular contact surfaces. The numerical and experimental results presented demonstrate that the stiffness of the actuators can be varied using a suitably profiled contact surface. The larger the radius of the contact surface is, the higher is the stiffness of the polymer actuators. The outcomes of this study suggest that, although the stiffness of the artificial muscles considered in this study is constant for a given geometric size, and electrical and chemical operation conditions, it can be changed in a nonlinear fashion to suit the stiffness requirement of a considered application. The stiffness enhancement methodology can be extended to other ionic-type conducting polymer actuators.

Mechanomyography-Based Wearable Monitor of Quasi-Isometric Muscle Fatigue for Motor Neural Prostheses.

PubMed

Krueger, Eddy; Popović-Maneski, Lana; Nohama, Percy

2018-02-01

A motor neural prosthesis based on surface functional electrical stimulation (sFES) can restore functional movement (e.g., standing, walking) in patients with a spinal cord injury (SCI). sFES generates muscle contractions in antigravity muscles and allows balance-assisted standing. This induced standing has several benefits, such as improved cardiovascular function, decreased incidence of urinary infections, reduced joint contractures, and muscle atrophy. The duration of sFES assisted standing is limited due to the quick onset of muscle fatigue. Currently, there is no method available to reliably estimate real-time muscle fatigue during sFES. Simply monitoring the M-wave changes is not suitable due to the high signal disturbances that arise during multi-channel electrical stimulation. Mechanomyography (MMG) is immune to electrical stimulation artifacts and can be used to detect subtle vibrations on the surface of the skin related to activation of the underlying muscle's motor units (MU). The aim of this study was to develop a method for detecting muscle fatigue brought on by sFES. The method was tested in three different heads of the quadriceps muscle in SCI patients during electrically elicited quasi-isometric contraction. Six spinal cord-injured male volunteers, with no voluntary control of the quadriceps muscle participated in the study. Electrical bursts of voltage-controlled monophasic square pulses at frequencies of 1 kHz (50% duty cycle) at 50 Hz (15% duty cycle) were used to generate thigh muscle contractions that controlled the knee joint in the sagittal plane. The pulse amplitudes were set to position the knee joint at a 5° angle from the horizontal plane and when the knee angle dropped to 20° (e.g., the quadriceps were unable to hold the lower leg in the desired position), the test was terminated. Two data segments lasting 10 s each, at the beginning and end of each test, were analyzed. The muscle contraction was assessed by MMG sensors positioned on the rectus femoris, vastus lateralis, and vastus medialis muscles. Data segments were decomposed into 11 frequency bands using a Cauchy wavelet transform. In the initial time interval (non-fatigued muscle), the power peak was concentrated in the 11.31 Hz frequency band. In the final interval (muscle fatigued) this peak shifted to lower frequencies (2 and 6 Hz frequency bands). The decreased frequency was most prominent during the last 4 s of the recordings. It was shown that MMG could be used as a real-time indicator of muscle fatigue during FES-induced isometric contraction of quadriceps; hence, MMG could be used in closed-loop control as a fatigue detector. Subsequent studies for non-isometric contractions could possibly lead to prediction of muscle fatigue before contractile failure during functional use of the muscle. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Modeling and analysis of a meso-hydraulic climbing robot with artificial muscle actuation.

PubMed

Chapman, Edward M; Jenkins, Tyler E; Bryant, Matthew

2017-11-08

This paper presents a fully coupled electro-hydraulic model of a bio-inspired climbing robot actuated by fluidic artificial muscles (FAMs). This analysis expands upon previous FAM literature by considering not only the force and contraction characteristics of the actuator, but the complete hydraulic and electromechanical circuits as well as the dynamics of the climbing robot. This analysis allows modeling of the time-varying applied pressure, electrical current, and actuator contraction for accurate prediction of the robot motion, energy consumption, and mechanical work output. The developed model is first validated against mechanical and electrical data collected from a proof-of-concept prototype robot. The model is then employed to study the system-level sensitivities of the robot locomotion efficiency and average climbing speed to several design and operating parameters. The results of this analysis demonstrate that considering only the transduction efficiency of the FAM actuators is insufficient to maximize the efficiency of the complete robot, and that a holistic approach can lead to significant improvements in performance.

Chordwise implementation of pneumatic artificial muscles to actuate a trailing edge flap

NASA Astrophysics Data System (ADS)

Vocke, R. D., III; Kothera, C. S.; Wereley, N. M.

2018-07-01

This work describes the theoretical design and experimental validation of a rotorcraft-specific trailing edge flap powered by pneumatic artificial muscle actuators. The actuators in this work are co-located outboard on the rotor blade with the flap and arranged with a chordwise orientation where diameter and length restrictions can severely limit the operating range of the system. Techniques for addressing this configuration, such as introducing a bias contraction and mechanism optimization, are discussed and a numerical optimization is performed for an actuation system sized for implementation on a medium utility helicopter rotor. The optimized design achieves ±10° of deflection at 1/rev, and maintains at least ±2° half peak-to-peak deflection out to 10/rev, indicating that the system has the actuation authority and bandwidth necessary for both primary control and vibration/noise reduction. Portions of this paper were presented at the AHS 70th Annual Forum, Montréal, Québec, Canada, May 20–22, 2014.

Nanothorn electrodes for ionic polymer-metal composite artificial muscles

PubMed Central

Palmre, Viljar; Pugal, David; Kim, Kwang J.; Leang, Kam K.; Asaka, Kinji; Aabloo, Alvo

2014-01-01

Ionic polymer-metal composites (IPMCs) have recently received tremendous interest as soft biomimetic actuators and sensors in various bioengineering and human affinity applications, such as artificial muscles and actuators, aquatic propulsors, robotic end-effectors, and active catheters. Main challenges in developing biomimetic actuators are the attainment of high strain and actuation force at low operating voltage. Here we first report a nanostructured electrode surface design for IPMC comprising platinum nanothorn assemblies with multiple sharp tips. The newly developed actuator with the nanostructured electrodes shows a new way to achieve highly enhanced electromechanical performance over existing flat-surfaced electrodes. We demonstrate that the formation and growth of the nanothorn assemblies at the electrode interface lead to a dramatic improvement (3- to 5-fold increase) in both actuation range and blocking force at low driving voltage (1–3 V). These advances are related to the highly capacitive properties of nanothorn assemblies, increasing significantly the charge transport during the actuation process. PMID:25146561

Thermo- and photo-driven soft actuators based on crosslinked liquid crystalline polymers

NASA Astrophysics Data System (ADS)

Gu, Wei; Wei, Jia; Yu, Yanlei

2016-09-01

Crosslinked liquid crystalline polymers (CLCPs) are a type of promising material that possess both the order of liquid crystals and the properties of polymer networks. The anisotropic deformation of the CLCPs takes place when the mesogens experience order to disorder change in response to external stimuli; therefore, they can be utilized to fabricate smart actuators, which have potential applications in artificial muscles, micro-optomechanical systems, optics, and energy-harvesting fields. In this review the recent development of thermo- and photo-driven soft actuators based on the CLCPs are summarized. Project supported by the National Natural Science Foundation of China (Grant Nos. 21134003, 21273048, 51225304, and 51203023) and Shanghai Outstanding Academic Leader Program, China (Grant No. 15XD1500600).

Hot and steady: Elevated temperatures do not enhance muscle disuse atrophy during prolonged aestivation in the ectotherm Cyclorana alboguttata.

PubMed

Young, K M; Cramp, R L; Franklin, C E

2013-02-01

Animals that undergo prolonged dormancy experience minimal muscle disuse atrophy (MDA) compared to animals subjected to artificial immobilisation over shorter timeframes. An association between oxidative stress and MDA suggests that metabolic depression presumably affords dormant animals some protection against muscle disuse. Because aerobic metabolism is temperature sensitive, we proposed that MDA in dormant (aestivating) ectotherms would be enhanced at elevated temperatures. In the green-striped burrowing frog, Cyclorana alboguttata, the thermal sensitivity of skeletal muscle metabolic rate is muscle-specific. We proposed that the degree of atrophy experienced during aestivation would correlate with the thermal sensitivity of muscle metabolic rate such that muscles with a relatively high metabolic rate at high temperatures would experience more disuse atrophy. To test this hypothesis, we examined the effect of temperature and aestivation on the extent of MDA in two functionally different muscles: the M. gastrocnemius (jumping muscle) and M. iliofibularis (non-jumping muscle), in C. alboguttata aestivating at 24 or 30 °C for 6 months. We compared a range of morphological parameters from muscle cross-sections stained with succinic dehydrogenase to show that muscle-specific patterns of disuse atrophy were consistent with the relative rates of oxygen consumption of those muscle types. However, despite muscle-specific differences in thermal sensitivity of metabolic rate, aestivation temperature did not influence the extent of atrophy in either muscle. Our results suggest that the muscles of frogs aestivating at high temperatures are defended against additional atrophy ensuring protection of muscle function during long periods of immobilisation. Copyright © 2012 Wiley Periodicals, Inc.

Automatic reconstruction of the muscle architecture from the superficial layer fibres data.

PubMed

Kohout, Josef; Cholt, David

2017-10-01

Physiological cross-sectional area (PCSA) of a muscle plays a significant role in determining the force contribution of muscle fascicles to skeletal movement. This parameter is typically calculated from the lengths of muscle fibres selectively sampled from the superficial layer of the muscle. However, recent studies have found that the length of fibres in the superficial layer often differs significantly (p < 0.5) from the length of fibres in the deep layer. As a result, PCSA estimation is inaccurate. In this paper, we propose a method to automatically reconstruct fibres in the whole volume of a muscle from those selectively sampled on the superficial layer. The method performs a centripetal Catmull-Rom interpolation of the input fibres within the volume of a muscle represented by its 3D surface model, automatically distributing the fibres among multiple heads of the muscle and shortening the deep fibres to support large attachment areas with extremely acute angles. Our C++ implementation runs in a couple of seconds on commodity hardware providing realistic results for both artificial and real data sets we tested. The fibres produced by the method can be used directly to determine the personalised mechanical muscle functioning. Our implementation is publicly available for the researchers at https://mi.kiv.zcu.cz/. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a reconstructed cornea from collagen-chondroitin sulfate foams and human cell cultures.

PubMed

Vrana, N Engin; Builles, Nicolas; Justin, Virginie; Bednarz, Jurgen; Pellegrini, Graziella; Ferrari, Barbara; Damour, Odile; Hulmes, David J S; Hasirci, Vasif

2008-12-01

To develop an artificial cornea, the ability to coculture the different cell types present in the cornea is essential. Here the goal was to develop a full-thickness artificial cornea using an optimized collagen-chondroitin sulfate foam, with a thickness close to that of human cornea, by coculturing human corneal epithelial and stromal cells and transfected human endothelial cells. Corneal extracellular matrix was simulated by a porous collagen/glycosaminoglycan-based scaffold seeded with stromal keratocytes and then, successively, epithelial and endothelial cells. Scaffolds were characterized for bulk porosity and pore size distribution. The performance of the three-dimensional construct was studied by histology, immunofluorescence, and immunohistochemistry. The scaffold had 85% porosity and an average pore size of 62.1 microm. Keratocytes populated the scaffold and produced a newly synthesized extracellular matrix as characterized by immunohistochemistry. Even though the keratocytes lost their CD34 phenotype marker, the absence of smooth muscle actin fibers showed that these cells had not differentiated into myofibroblasts. The epithelial cells formed a stratified epithelium and began basement membrane deposition. An endothelial cell monolayer beneath the foam was also apparent. These results demonstrate that collagen-chondroitin sulfate scaffolds are good substrates for artificial cornea construction with good resilience, long-term culture capability, and handling properties.

Soft Robotic Manipulation and Locomotion with a 3D Printed Electroactive Hydrogel.

PubMed

Han, Daehoon; Farino, Cindy; Yang, Chen; Scott, Tracy; Browe, Daniel; Choi, Wonjoon; Freeman, Joseph W; Lee, Howon

2018-05-30

Electroactive hydrogels (EAH) that exhibit large deformation in response to an electric field have received great attention as a potential actuating material for soft robots and artificial muscle. However, their application has been limited due to the use of traditional two-dimensional (2D) fabrication methods. Here we present soft robotic manipulation and locomotion with 3D printed EAH microstructures. Through 3D design and precise dimensional control enabled by a digital light processing (DLP) based micro 3D printing technique, complex 3D actuations of EAH are achieved. We demonstrate soft robotic actuations including gripping and transporting an object and a bidirectional locomotion.

Artificial Muscle (AM) Cilia Array for Underwater Systems

DTIC Science & Technology

2016-12-15

Polymer Metal-Composites for Soft Robotic Applications, 3D printing Workshop, Las Vegas, Nevada, April15, 2016 2. J. D. Carrico, J. Erickson , K. K. Leang...student, UU 10. John Erickson , undergraduate student, UU 11. Marissa Tsugawa, MS student, UNR Page I 20 Cillia ONR Final Report

Muscle contraction: A mechanical perspective.

PubMed

Marcucci, L; Truskinovsky, L

2010-08-01

In this paper we present a purely mechanical analog of the conventional chemo-mechanical modeling of muscle contraction. We abandon the description of kinetics of the power stroke in terms of jump processes and instead resolve the continuous stochastic evolution on an appropriate energy landscape. In general physical terms, we replace hard spin chemical variables by soft spin variables representing mechanical snap-springs. This allows us to treat the case of small and even disappearing barriers and, more importantly, to incorporate the mechanical representation of the power stroke into the theory of Brownian ratchets. The model provides the simplest non-chemical description for the main stages of the biochemical Lymn-Taylor cycle and may be used as a basis for the artificial micro-mechanical reproduction of the muscle contraction mechanism.

Hydraulically amplified self-healing electrostatic actuators with muscle-like performance

NASA Astrophysics Data System (ADS)

Acome, E.; Mitchell, S. K.; Morrissey, T. G.; Emmett, M. B.; Benjamin, C.; King, M.; Radakovitz, M.; Keplinger, C.

2018-01-01

Existing soft actuators have persistent challenges that restrain the potential of soft robotics, highlighting a need for soft transducers that are powerful, high-speed, efficient, and robust. We describe a class of soft actuators, termed hydraulically amplified self-healing electrostatic (HASEL) actuators, which harness a mechanism that couples electrostatic and hydraulic forces to achieve a variety of actuation modes. We introduce prototypical designs of HASEL actuators and demonstrate their robust, muscle-like performance as well as their ability to repeatedly self-heal after dielectric breakdown—all using widely available materials and common fabrication techniques. A soft gripper handling delicate objects and a self-sensing artificial muscle powering a robotic arm illustrate the wide potential of HASEL actuators for next-generation soft robotic devices.

Neuro-prosthetic interplay. Comment on "Hand synergies: Integration of robotics and neuroscience for understanding the control of biological and artificial hands" by M. Santello et al.

NASA Astrophysics Data System (ADS)

Schieber, Marc H.

2016-07-01

Control of the human hand has been both difficult to understand scientifically and difficult to emulate technologically. The article by Santello and colleagues in the current issue of Physics of Life Reviews[1] highlights the accelerating pace of interaction between the neuroscience of controlling body movement and the engineering of robotic hands that can be used either autonomously or as part of a motor neuroprosthesis, an artificial body part that moves under control from a human subject's own nervous system. Motor neuroprostheses typically involve a brain-computer interface (BCI) that takes signals from the subject's nervous system or muscles, interprets those signals through a decoding algorithm, and then applies the resulting output to control the artificial device.

[The application of artificial protein premixes for nutritive support of patients with chronic renal insufficiency, being treated by perinateal dialysis].

PubMed

Pichugina, I S; Vetchinnikova, O N; Vereshchagina, V M; Gapparov, M M; Vatazin, A V

2008-01-01

As a result of a survey of 56 patients with chronic renal insufficiency, who undergone hemodialysis, it was established, that clinical condition of patients, biochemical and hematological blood indices as well as results of anthropometric research improve upon application of artificial balanced high-protein premixes -"Nutrinil" and "Nutrien-Nefro". Irrespective of way of administration - introperitoneal ("Nutrinil" solution) or enteral ("Nutrien-Nefro" mixture) protein-energetic insufficiency diminishes or totally disappears, body weight, fat and muscle content of the body weight, as well as indices of whole protein, albumine, lymphocytes, haemoglobin, pH approache the norm. Intraperitoneal way of administration of artificial protein premixes increase patients adherence to this procedure, though enteral way of their administration is more preferable from economic point of view.

Replacement of long segments of the esophagus with a collagen-silicone composite tube.

PubMed

Takimoto, Y; Nakamura, T; Teramachi, M; Kiyotani, T; Shimizu, Y

1995-01-01

Artificial esophagi designed thus far can be classified into three types in terms of the materials used: natural, artificial, and composite. In conventional models, even when artificial esophagi were made of ideal materials with high tissue affinity, they remained in the tissue as a foreign body, and therefore were not free of the complications caused by implanted material. The authors have designed a new type of artificial esophagus composed of a Silicone tube covered with nonantigenic collagen. The novel feature of this artificial esophagus is that the prosthesis does not remain in the implanted site, but is replaced by regenerated host tissue. Using this artificial esophagus, the authors have already succeeded in replacing a 5 cm gap in the esophagus. In this study, replacement of longer portions of the esophagus was assessed in seven dogs using a 10 cm long artificial esophagus. Stenosis did not occur in five of the seven dogs and, consequently, these dogs survived by oral feeding alone for more than 6 months without dry weight loss. The other two animals died of anesthetic accidents at the time of stent removal 6 weeks after surgery. In both cases, the internal surface of the neoesophagus was covered with a polylayer of squamous epithelium. Regenerated esophagi had normal esophageal glands and immature muscle tissue. It is therefore concluded that this new artificial esophagus is also applicable for replacement of long segments of esophagus.

Afferent control mechanisms involved in the development of soleus fiber alterations in simulated hypogravity

NASA Astrophysics Data System (ADS)

Shenkman, B. S.; Nemirovskaya, T. L.; Shapovalova, K. B.; Podlubnaya, Z. A.; Vikhliantsev, I. M.; Moukhina, A. M.; Kozlovskaya, I. B.

2007-02-01

It was recently established that support withdrawal (withdrawal of support reaction force) in microgravity provokes a sequence of functional shifts in the activity of motor units (inactivation of slow ones) and peripheral muscle apparatus which lead to the decline of postural muscle contractility and alterations in fiber characteristics. However, mechanisms involved in inactivation of the slow motor units and appropriate slow-twitch muscle fiber disuse under the supportless conditions remained unknown. We show here that artificial inactivation of muscles-antagonists (which are known to be hyperactive during unloading) counteracts some of the unloading-induced events in the rat soleus (fiber size reduction, slow-to-fast fiber-type transition and decline of titin and nebulin content). It was also demonstrated that direct activation of the muscarinic receptors of the neostriatum neurons prevented slow-to-fast fiber-type transformation in soleus of hindlimb suspended rats.

Combined feedforward and feedback control of a redundant, nonlinear, dynamic musculoskeletal system.

PubMed

Blana, Dimitra; Kirsch, Robert F; Chadwick, Edward K

2009-05-01

A functional electrical stimulation controller is presented that uses a combination of feedforward and feedback for arm control in high-level injury. The feedforward controller generates the muscle activations nominally required for desired movements, and the feedback controller corrects for errors caused by muscle fatigue and external disturbances. The feedforward controller is an artificial neural network (ANN) which approximates the inverse dynamics of the arm. The feedback loop includes a PID controller in series with a second ANN representing the nonlinear properties and biomechanical interactions of muscles and joints. The controller was designed and tested using a two-joint musculoskeletal model of the arm that includes four mono-articular and two bi-articular muscles. Its performance during goal-oriented movements of varying amplitudes and durations showed a tracking error of less than 4 degrees in ideal conditions, and less than 10 degrees even in the case of considerable fatigue and external disturbances.

Space artificial gravity facilities - An approach to their construction

NASA Technical Reports Server (NTRS)

Wercinski, P. F.; Searby, N. D.; Tillman, B. W.

1988-01-01

In the course of adaptation to a space microgravity environment, humans experience cardiovascular deconditioning, loss of muscle mass, and loss of bone minerals. One possible solution to these space adaptation problems is to simulate earth's gravity using the centripetal acceleration created by a rotating system. The design and construction of rotating space structures pose many challenges. Before committing to the use of artificial gravity in future space missions, a man-rated Variable Gravity Research Facility (VGRF) should be developed in earth orbit as a gravitational research tool and testbed. This paper addresses the requirements and presents preliminary concepts for such a facility.

Impact of Cricothyroid Muscle Contraction on Vocal Fold Vibration: Experimental Study with High-Speed Videoendoscopy.

PubMed

Ishikawa, Camila Cristina; Pinheiro, Thais Gonçalves; Hachiya, Adriana; Montagnoli, Arlindo Neto; Tsuji, Domingos Hiroshi

2017-05-01

The aim of this study was to evaluate the effects of cricothyroid muscle contraction on vocal fold vibration, as evaluated with high-speed videoendoscopy, and to identify one or more aspects of vocal fold vibration that could be used as an irrefutable indicator of unilateral cricothyroid muscle paralysis. This was an experimental study employing excised human larynges. Twenty freshly excised human larynges were evaluated during artificially produced vibration. Each larynx was assessed in three situations: bilateral cricothyroid muscle contraction, unilateral cricothyroid muscle contraction, and no contraction of either cricothyroid muscle. The following parameters were evaluated by high-speed videoendoscopy: fundamental frequency, periodicity, amplitude of vocal fold vibration, and phase symmetry between the vocal folds. Although neither unilateral nor bilateral cricothyroid muscle contraction altered the periodicity of vibration or the occurrence of phase asymmetry, there was a significant decrease in fundamental frequency in parallel with decreasing longitudinal tension. We also found an increase in vibration amplitude of right and left vocal folds, which were similar in terms of their behavior for this parameter in the various situations studied. Our results suggest that differences in vibration amplitude and phase symmetry between vocal folds are not reliable indicators of unilateral cricothyroid muscle paralysis. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Ground-based assessment of JAXA mouse habitat cage unit by mouse phenotypic studies

PubMed Central

Shimbo, Miki; Kudo, Takashi; Hamada, Michito; Jeon, Hyojung; Imamura, Yuki; Asano, Keigo; Okada, Risa; Tsunakawa, Yuki; Mizuno, Seiya; Yagami, Ken-ichi; Ishikawa, Chihiro; Li, Haiyan; Shiga, Takashi; Ishida, Junji; Hamada, Juri; Murata, Kazuya; Ishimaru, Tomohiro; Hashimoto, Misuzu; Fukamizu, Akiyoshi; Yamane, Mutsumi; Ikawa, Masahito; Morita, Hironobu; Shinohara, Masahiro; Asahara, Hiroshi; Akiyama, Taishin; Akiyama, Nobuko; Sasanuma, Hiroki; Yoshida, Nobuaki; Zhou, Rui; Wang, Ying-Ying; Ito, Taito; Kokubu, Yuko; Noguchi, Taka-aki K.; Ishimine, Hisako; Kurisaki, Akira; Shiba, Dai; Mizuno, Hiroyasu; Shirakawa, Masaki; Ito, Naoki; Takeda, Shin; Takahashi, Satoru

2016-01-01

The Japan Aerospace Exploration Agency developed the mouse Habitat Cage Unit (HCU) for installation in the Cell Biology Experiment Facility (CBEF) onboard the Japanese Experimental Module (“Kibo”) on the International Space Station. The CBEF provides “space-based controls” by generating artificial gravity in the HCU through a centrifuge, enabling a comparison of the biological consequences of microgravity and artificial gravity of 1 g on mice housed in space. Therefore, prior to the space experiment, a ground-based study to validate the habitability of the HCU is necessary to conduct space experiments using the HCU in the CBEF. Here, we investigated the ground-based effect of a 32-day housing period in the HCU breadboard model on male mice in comparison with the control cage mice. Morphology of skeletal muscle, the thymus, heart, and kidney, and the sperm function showed no critical abnormalities between the control mice and HCU mice. Slight but significant changes caused by the HCU itself were observed, including decreased body weight, increased weights of the thymus and gastrocnemius, reduced thickness of cortical bone of the femur, and several gene expressions from 11 tissues. Results suggest that the HCU provides acceptable conditions for mouse phenotypic analysis using CBEF in space, as long as its characteristic features are considered. Thus, the HCU is a feasible device for future space experiments. PMID:26822934

Ground-based assessment of JAXA mouse habitat cage unit by mouse phenotypic studies.

PubMed

Shimbo, Miki; Kudo, Takashi; Hamada, Michito; Jeon, Hyojung; Imamura, Yuki; Asano, Keigo; Okada, Risa; Tsunakawa, Yuki; Mizuno, Seiya; Yagami, Ken-Ichi; Ishikawa, Chihiro; Li, Haiyan; Shiga, Takashi; Ishida, Junji; Hamada, Juri; Murata, Kazuya; Ishimaru, Tomohiro; Hashimoto, Misuzu; Fukamizu, Akiyoshi; Yamane, Mutsumi; Ikawa, Masahito; Morita, Hironobu; Shinohara, Masahiro; Asahara, Hiroshi; Akiyama, Taishin; Akiyama, Nobuko; Sasanuma, Hiroki; Yoshida, Nobuaki; Zhou, Rui; Wang, Ying-Ying; Ito, Taito; Kokubu, Yuko; Noguchi, Taka-Aki K; Ishimine, Hisako; Kurisaki, Akira; Shiba, Dai; Mizuno, Hiroyasu; Shirakawa, Masaki; Ito, Naoki; Takeda, Shin; Takahashi, Satoru

2016-05-20

The Japan Aerospace Exploration Agency developed the mouse Habitat Cage Unit (HCU) for installation in the Cell Biology Experiment Facility (CBEF) onboard the Japanese Experimental Module ("Kibo") on the International Space Station. The CBEF provides "space-based controls" by generating artificial gravity in the HCU through a centrifuge, enabling a comparison of the biological consequences of microgravity and artificial gravity of 1 g on mice housed in space. Therefore, prior to the space experiment, a ground-based study to validate the habitability of the HCU is necessary to conduct space experiments using the HCU in the CBEF. Here, we investigated the ground-based effect of a 32-day housing period in the HCU breadboard model on male mice in comparison with the control cage mice. Morphology of skeletal muscle, the thymus, heart, and kidney, and the sperm function showed no critical abnormalities between the control mice and HCU mice. Slight but significant changes caused by the HCU itself were observed, including decreased body weight, increased weights of the thymus and gastrocnemius, reduced thickness of cortical bone of the femur, and several gene expressions from 11 tissues. Results suggest that the HCU provides acceptable conditions for mouse phenotypic analysis using CBEF in space, as long as its characteristic features are considered. Thus, the HCU is a feasible device for future space experiments.

Performance of swine chilled during artificial rearing.

PubMed

Stanton, H C; Mueller, R L

1977-07-01

There were more deaths among neonatal swine artificially reared for 21 days in individual cages at 27.9 C than among pigs reared under similar conditions at thermoneutrality (34.6 C). Furthermore, these deaths occurred at a younger age in the chilled animals. Chilled swine gained less body weight than did warm pigs for the first 15 days of life, although the survivors of the 27.9 C environment weighed the same as warm survivors at 22 days of age. Plasma glucose, liver, and skeletal muscle glycogen concentrations were significantly lower in neonatal swine exposed to 27.9 C from 1 to 4 days of age. Plasma nonesterified fatty acids, glycerol, cholesterol, and triglyceride concentrations were not altered by chilling. However, these lipid variables were significantly higher in 4-day-old nursig pigs than in animals reared artificially for the same period on artificial food. Adrenal gland weights and adrenal medullary catecholamine-synthetic enzyme activities were not altered by exposure to 27.9 C in pigs 1 to 4 days of age.

Micro- and nanostructured electro-active polymer actuators as smart muscles for incontinence treatment

NASA Astrophysics Data System (ADS)

Osmani, Bekim; Töpper, Tino; Deschenaux, Christian; Nohava, Jiri; Weiss, Florian M.; Leung, Vanessa; Müller, Bert

2015-02-01

Treatments of severe incontinence are currently based on purely mechanical systems that generally result in revision after three to five years. Our goal is to develop a prototype acting in a natural-analogue manner as artificial muscle, which is based on electro-active polymers. Dielectric actuators have outstanding performances including millisecond response times, mechanical strains of more than 10 % and power to mass densities similar to natural muscles. They basically consist of polymer films sandwiched between two compliant electrodes. The incompressible but elastic polymer film transduces the electrical energy into mechanical work according to the Maxwell pressure. Available polymer films are micrometers thick and voltages as large as kV are necessary to obtain 10 % strain. For medical implants, polymer films should be nanometer thin to realize actuation below 48 V. The metallic electrodes have to be stretchable to follow the strain of 10 % and remain conductive. Recent results on the stress/strain behavior of anisotropic EAP-cantilevers have shown dependencies on metal electrode preparation. We have investigated tunable anisotropic micro- and nanostructures for metallic electrodes. They show a preferred actuation direction with improved stress-strain behavior. The bending of the cantilever has been characterized by the laser beam deflection method. The impact of the electrode on the effective Young's Modulus is measured using an Ultra Nanoindentation Tester with an integrated reference system for soft polymer surfaces. Once ten thousand layers of nanometer-thin EAP actuators are available, devices beyond the envisioned application will flood the market.

Artificial Gravity as a Multi-System Countermeasure to Bed Rest Deconditioning: Preliminary Results

NASA Technical Reports Server (NTRS)

Warren, L. E.; Paloski, William H.; Young, L. R.

2006-01-01

Artificial gravity paradigms may offer effective, efficient, multi-system protection from the untoward effects of adaptation to the microgravity of space or the hypogravity of planetary surfaces. Intermittent artificial gravity (AG) produced by a horizontal short-radius centrifuge (SRC) has recently been utilized on human test subjects deconditioned by bed rest. This presentation will review preliminary results of a 41 day study conducted at the University of Texas Medical Branch, Galveston, TX bed rest facility. During the first eleven days of the protocol, subjects were ambulatory, but confined to the facility. They began a carefully controlled diet, and participated in multiple baseline tests of bone, muscle, cardiovascular, sensory-motor, immunological, and psychological function. On the twelfth day, subjects entered the bed rest phase of the study, during which they were confined to strict 6deg head down tilt bed rest for 21 days. Beginning 24 hrs into this period, treatment subjects received one hour daily exposures to artificial gravity which was produced by spinning the subjects on a 3.0 m radius SRC. They were oriented radially in the supine position so that the centrifugal force was aligned with their long body axis, and while spinning, they "stood" on a force plate, supporting the centrifugal loading (2.5 g at the feet, 1.0 g at the heart). The subject station allowed free translation over approximately 10 cm to ensure full loading of the lower extremities and to allow for anti-orthostatic muscle contractions. Control subjects were positioned on the centrifuge but did not spin. Following the bed rest phase, subjects were allowed to ambulate again, but remained within the facility for an additional 9 days and participated in multiple follow-up tests of physiological function.

Combining ergometer exercise and artificial gravity in a compact-radius centrifuge

NASA Astrophysics Data System (ADS)

Diaz, Ana; Trigg, Chris; Young, Laurence R.

2015-08-01

Humans experience physiological deconditioning during space missions, primarily attributable to weightlessness. Some of these adverse consequences include bone loss, muscle atrophy, sensory-motor deconditioning, and cardiovascular alteration, which may lead to orthostatic intolerance when astronauts return to Earth. Artificial gravity could provide a comprehensive countermeasure capable of challenging all the physiological systems at once, particularly if combined with exercise, thereby maintaining overall health during extended exposure to weightlessness. A new Compact Radius Centrifuge (CRC) platform was designed and built on the existing Short Radius Centrifuge (SRC) at the Massachusetts Institute of Technology (MIT). The centrifuge has been constrained to a radius of 1.4 m, the upper radial limit for a centrifuge to fit within an International Space Station (ISS) module without extensive structural alterations. In addition, a cycle ergometer has been added for exercise during centrifugation. The CRC now includes sensors of foot forces, cardiovascular parameters, and leg muscle electromyography. An initial human experiment was conducted on 12 subjects to analyze the effects of different artificial gravity levels (0 g, 1 g, and 1.4 g, measured at the feet) and ergometer exercise intensities (25 W warm-up, 50 W moderate and 100 W vigorous) on the musculoskeletal function as well as motion sickness and comfort. Foot forces were measured during the centrifuge runs, and subjective comfort and motion sickness data were gathered after each session. Preliminary results indicate that ergometer exercise on a centrifuge may be effective in improving musculoskeletal function. The combination is well tolerated and motion sickness is minimal. The MIT CRC is a novel platform for future studies of exercise combined with artificial gravity. This combination may be effective as a countermeasure to space physiological deconditioning.

Electroactive Polymers as Artificial Muscles - Reality and Challenges

NASA Technical Reports Server (NTRS)

Bar-Cohen, Y.

2001-01-01

Electroactive Polymers (EAPs) are emerging as effective displacement actuators. These materials offer the closest resemblance of biological muscle potentially enabling unique capabilities changing the paradigm about robots construction. Under a NASA task, several EAP driven mechanisms were developed including dust wiper, gripper, and robotic arm EAP are inducing a low actuation force limiting the applications that can use their current capability. In recognition of this limitation a series of international forums were established including SPIE conference, Webhub, Newsletter, and Newsgroup. A challenge was posed to the EAP community to have an arm wrestling between robot that is equipped with EAP actuators and human.

Genital Autocleaning in the Male Cricket Gryllus bimaculatus (2): Rhythmic Movements of the Genitalia and Their Motor Control.

PubMed

Kumashiro, Mikihiko; Sakai, Masaki

2016-12-01

Three types of genital movement, their neural controls, and functional roles were investigated to gain a better understanding of the mechanism underlying autocleaning in the male cricket. The membrane complex consisting of the median pouch and genital chamber floor shows peculiar undulation that is composed of two types of movements: a right-left large shift and small crease-like movements. The large shift was caused by contraction of a pair of muscles (MPA) located anterior to the median pouch, while the crease-like movements were caused by numerous muscle fibers extending over the membrane complex. The MPA and muscle fibers were each innervated by efferent neurons in the terminal abdominal ganglion. Experiments with artificial dirt mimicking a foreign object revealed that the crease-like movements were responsible for dirt transport, while the large shift participated in sweeping the dirt into the lateral pouch as a trash container. On the other hand, the dorsal pouch serving as a template for the spermatophore showed a jerky bending movement. Simultaneous monitoring of the membrane complex and dorsal pouch activities suggested that their movements cooperate to enable the efficient evacuation of waste in the dorsal pouch. Based on the results, we conclude that genital autocleaning supports the production of the spermatophore.

Plasticity of the Muscle Stem Cell Microenvironment.

PubMed

Dinulovic, Ivana; Furrer, Regula; Handschin, Christoph

2017-01-01

Satellite cells (SCs) are adult muscle stem cells capable of repairing damaged and creating new muscle tissue throughout life. Their functionality is tightly controlled by a microenvironment composed of a wide variety of factors, such as numerous secreted molecules and different cell types, including blood vessels, oxygen, hormones, motor neurons, immune cells, cytokines, fibroblasts, growth factors, myofibers, myofiber metabolism, the extracellular matrix and tissue stiffness. This complex niche controls SC biology-quiescence, activation, proliferation, differentiation or renewal and return to quiescence. In this review, we attempt to give a brief overview of the most important players in the niche and their mutual interaction with SCs. We address the importance of the niche to SC behavior under physiological and pathological conditions, and finally survey the significance of an artificial niche both for basic and translational research purposes.

Surface electromyographic mapping of the orbicularis oculi muscle for real-time blink detection.

PubMed

Frigerio, Alice; Cavallari, Paolo; Frigeni, Marta; Pedrocchi, Alessandra; Sarasola, Andrea; Ferrante, Simona

2014-01-01

Facial paralysis is a life-altering condition that significantly impairs function, appearance, and communication. Facial rehabilitation via closed-loop pacing represents a potential but as yet theoretical approach to reanimation. A first critical step toward closed-loop facial pacing in cases of unilateral paralysis is the detection of healthy movements to use as a trigger to prosthetically elicit automatic artificial movements on the contralateral side of the face. To test and to maximize the performance of an electromyography (EMG)-based blink detection system for applications in closed-loop facial pacing. Blinking was detected across the periocular region by means of multichannel surface EMG at an academic neuroengineering and medical robotics laboratory among 15 healthy volunteers. Real-time blink detection was accomplished by mapping the surface of the orbicularis oculi muscle on one side of the face with a multichannel surface EMG. The biosignal from each channel was independently processed; custom software registered a blink when an amplitude-based or slope-based suprathreshold activity was detected. The experiments were performed when participants were relaxed and during the production of particular orofacial movements. An F1 score metric was used to analyze software performance in detecting blinks. The maximal software performance was achieved when a blink was recorded from the superomedial orbit quadrant. At this recording location, the median F1 scores were 0.89 during spontaneous blinking, 0.82 when chewing gum, 0.80 when raising the eyebrows, and 0.70 when smiling. The overall performance of blink detection was significantly better at the superomedial quadrant (F1 score, 0.75) than at the traditionally used inferolateral quadrant (F1 score, 0.40) (P < .05). Electromyographic recording represents an accurate tool to detect spontaneous blinks as part of closed-loop facial pacing systems. The early detection of blink activity may allow real-time pacing via rapid triggering of contralateral muscles. Moreover, an EMG detection system can be integrated in external devices and in implanted neuroprostheses. A potential downside to this approach involves cross talk from adjacent muscles, which can be notably reduced by recording from the superomedial quadrant of the orbicularis oculi muscle and by applying proper signal processing. NA.

A Study of Some Problems in Network Information Theory

ERIC Educational Resources Information Center

Kamath, Sudeep Uday

2013-01-01

Red snapper, "Lutjanus campechanus," were sampled with hook and line at natural (n = 33) and artificial (n = 27) reef sites in the northern Gulf of Mexico from 2009-2011. Stomachs (n = 708) were extracted and their contents preserved for gut content analysis, and muscle tissue samples (n = 200) were dissected and frozen for stable…

Biomimetic robots using EAP as artificial muscles - progress and challenges

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2004-01-01

Biology offers a great model for emulation in areas ranging from tools, computational algorithms, materials science, mechanisms and information technology. In recent years, the field of biomimetics, namely mimicking biology, has blossomed with significant advances enabling the reverse engineering of many animals' functions and implementation of some of these capabilities.

Microgravity induced changes in the control of motor units

NASA Astrophysics Data System (ADS)

de Luca, C.; Roy, S.

The goal of this project is to understand the effects of microgravity on the control of muscles. It is motivated by the notion that in order to adequately address microgravity-induced deterioration in the force generating capacity of muscles, one needs to understand the changes in the control aspects in addition to histochemical and morphological changes. The investigations into muscle control need to include the regulation of the firing activity of motor units that make up a muscle and the coordination of different muscles responsible for the control of a joint. In order to understand the effects of microgravity on these two aspects of muscle control, we will test astronauts before and after spaceflight. The investigations of the control of motor units will involve intramuscular EMG techniques developed in our laboratory. We will use a quadrifilar electrode to detect simultaneously three differential channels of EMG activity. These data will be decomposed accurately using a sophisticated set of algorithms constructed with artificial intelligence knowledge- based techniques. Particular attention will be paid to the firing rate and recruitment behavior of motor units and we will study the degree of cross-correlation of the firing rates. This approach will enable us to study the firing behavior of several (approx. 10) concurrently active motor units. This analysis will enable us to detect modifications in the control of motor units. We will perform these investigations in a hand muscle, which continues being used in prehensile tasks in space, and a leg muscle whose antigravity role is not needed in space. The comparison of the effects of weightlessness on these muscles will determine if continued use of muscles in space deters the possible deleterious effects of microgravity on the control of motor units, in addition to slowing down atrophy. We are particularly interested in comparing the results of this study to similar data already obtained from elderly subjects, because the deleterious effects of migrogravity on muscles is in many ways similar to that of aging. Additionally, we will employ surface EMG techniques to evaluate the effects of microgravity on the coordination of muscles controlling a joint. We will study if the relative contributions from the muscles around the knee joint are redistributed after exposure to microgravity. The insight to be gained from this study will be important in developing countermeasures for maintaining the force generating capacity of muscles in microgravity and rehabilitation programs for aiding in recovery upon return to earth.

Proof of concept of an artificial muscle: theoretical model, numerical model, and hardware experiment.

PubMed

Haeufle, D F B; Günther, M; Blickhan, R; Schmitt, S

2011-01-01

Recently, the hyperbolic Hill-type force-velocity relation was derived from basic physical components. It was shown that a contractile element CE consisting of a mechanical energy source (active element AE), a parallel damper element (PDE), and a serial element (SE) exhibits operating points with hyperbolic force-velocity dependency. In this paper, the contraction dynamics of this CE concept were analyzed in a numerical simulation of quick release experiments against different loads. A hyperbolic force-velocity relation was found. The results correspond to measurements of the contraction dynamics of a technical prototype. Deviations from the theoretical prediction could partly be explained by the low stiffness of the SE, which was modeled analog to the metal spring in the hardware prototype. The numerical model and hardware prototype together, are a proof of this CE concept and can be seen as a well-founded starting point for the development of Hill-type artificial muscles. This opens up new vistas for the technical realization of natural movements with rehabilitation devices. © 2011 IEEE

Series Pneumatic Artificial Muscles (sPAMs) and Application to a Soft Continuum Robot.

PubMed

Greer, Joseph D; Morimoto, Tania K; Okamura, Allison M; Hawkes, Elliot W

2017-01-01

We describe a new series pneumatic artificial muscle (sPAM) and its application as an actuator for a soft continuum robot. The robot consists of three sPAMs arranged radially round a tubular pneumatic backbone. Analogous to tendons, the sPAMs exert a tension force on the robot's pneumatic backbone, causing bending that is approximately constant curvature. Unlike a traditional tendon driven continuum robot, the robot is entirely soft and contains no hard components, making it safer for human interaction. Models of both the sPAM and soft continuum robot kinematics are presented and experimentally verified. We found a mean position accuracy of 5.5 cm for predicting the end-effector position of a 42 cm long robot with the kinematic model. Finally, closed-loop control is demonstrated using an eye-in-hand visual servo control law which provides a simple interface for operation by a human. The soft continuum robot with closed-loop control was found to have a step-response rise time and settling time of less than two seconds.

Series Pneumatic Artificial Muscles (sPAMs) and Application to a Soft Continuum Robot

PubMed Central

Greer, Joseph D.; Morimoto, Tania K.; Okamura, Allison M.; Hawkes, Elliot W.

2017-01-01

We describe a new series pneumatic artificial muscle (sPAM) and its application as an actuator for a soft continuum robot. The robot consists of three sPAMs arranged radially round a tubular pneumatic backbone. Analogous to tendons, the sPAMs exert a tension force on the robot’s pneumatic backbone, causing bending that is approximately constant curvature. Unlike a traditional tendon driven continuum robot, the robot is entirely soft and contains no hard components, making it safer for human interaction. Models of both the sPAM and soft continuum robot kinematics are presented and experimentally verified. We found a mean position accuracy of 5.5 cm for predicting the end-effector position of a 42 cm long robot with the kinematic model. Finally, closed-loop control is demonstrated using an eye-in-hand visual servo control law which provides a simple interface for operation by a human. The soft continuum robot with closed-loop control was found to have a step-response rise time and settling time of less than two seconds. PMID:29379672

Design of flat pneumatic artificial muscles

NASA Astrophysics Data System (ADS)

Wirekoh, Jackson; Park, Yong-Lae

2017-03-01

Pneumatic artificial muscles (PAMs) have gained wide use in the field of robotics due to their ability to generate linear forces and motions with a simple mechanism, while remaining lightweight and compact. However, PAMs are limited by their traditional cylindrical form factors, which must increase radially to improve contraction force generation. Additionally, this form factor results in overly complicated fabrication processes when embedded fibers and sensor elements are required to provide efficient actuation and control of the PAMs while minimizing the bulkiness of the overall robotic system. In order to overcome these limitations, a flat two-dimensional PAM capable of being fabricated using a simple layered manufacturing process was created. Furthermore, a theoretical model was developed using Von Karman’s formulation for large deformations and the energy methods. Experimental characterizations of two different types of PAMs, a single-cell unit and a multi-cell unit, were performed to measure the maximum contraction lengths and forces at input pressures ranging from 0 to 150 kPa. Experimental data were then used to verify the fidelity of the theoretical model.

Observation and imitation of actions performed by humans, androids, and robots: an EMG study

PubMed Central

Hofree, Galit; Urgen, Burcu A.; Winkielman, Piotr; Saygin, Ayse P.

2015-01-01

Understanding others’ actions is essential for functioning in the physical and social world. In the past two decades research has shown that action perception involves the motor system, supporting theories that we understand others’ behavior via embodied motor simulation. Recently, empirical approach to action perception has been facilitated by using well-controlled artificial stimuli, such as robots. One broad question this approach can address is what aspects of similarity between the observer and the observed agent facilitate motor simulation. Since humans have evolved among other humans and animals, using artificial stimuli such as robots allows us to probe whether our social perceptual systems are specifically tuned to process other biological entities. In this study, we used humanoid robots with different degrees of human-likeness in appearance and motion along with electromyography (EMG) to measure muscle activity in participants’ arms while they either observed or imitated videos of three agents produce actions with their right arm. The agents were a Human (biological appearance and motion), a Robot (mechanical appearance and motion), and an Android (biological appearance and mechanical motion). Right arm muscle activity increased when participants imitated all agents. Increased muscle activation was found also in the stationary arm both during imitation and observation. Furthermore, muscle activity was sensitive to motion dynamics: activity was significantly stronger for imitation of the human than both mechanical agents. There was also a relationship between the dynamics of the muscle activity and motion dynamics in stimuli. Overall our data indicate that motor simulation is not limited to observation and imitation of agents with a biological appearance, but is also found for robots. However we also found sensitivity to human motion in the EMG responses. Combining data from multiple methods allows us to obtain a more complete picture of action understanding and the underlying neural computations. PMID:26150782

Artificial neural networks in knee injury risk evaluation among professional football players

NASA Astrophysics Data System (ADS)

Martyna, Michałowska; Tomasz, Walczak; Krzysztof, Grabski Jakub; Monika, Grygorowicz

2018-01-01

Lower limb injury risk assessment was proposed, based on isokinetic examination that is a part of standard athlete's biomechanical evaluation performed mainly twice a year. Information about non-contact knee injury (or lack of the injury) sustained within twelve months after isokinetic test, confirmed in USG were verified. Three the most common types of football injuries were taken into consideration: anterior cruciate ligament (ACL) rupture, hamstring and quadriceps muscles injuries. 22 parameters, obtained from isokinetic tests were divided into 4 groups and used as input parameters of five feedforward artificial neural networks (ANNs). The 5th group consisted of all considered parameters. The networks were trained with the use of Levenberg-Marquardt backpropagation algorithm to return value close to 1 for the sets of parameters corresponding injury event and close to 0 for parameters with no injury recorded within 6 - 12 months after isokinetic test. Results of this study shows that ANN might be useful tools, which simplify process of simultaneous interpretation of many numerical parameters, but the most important factor that significantly influence the results is database used for ANN training.

Caracterizacion de musculos artificiales con capacidades sensores/actuadores e intercambio mayoritario de cationes

NASA Astrophysics Data System (ADS)

Valero Conzuelo, Laura Luz

Over the past decade scientific research has been looking for new biomimetic materials able to imitate human organs behaviour, in such a way that is possible to apply them on different technologies: low cost ones, scalable ones, low energy consumption ones and on those with high potentialities in areas such as health, robotics, artificial nerves and muscles, among others. Most of the studied materials mimic the extracellular matrix (ECM) of living cells and its physical functions. Now, and for the first time, conducting polymers, and other electroactive materials exchange ions and water through electrochemical reactions: the material becomes a dense electroactive gel. The content of mentioned gel and the reactions happening in it mimic, by the first time in the history of science, the composition (in its simplest expression) and reactions taking place in the reactive intracellular matrix of the functional cells of living beings. During the chemical reactions (oxidation or reduction) the gel relative composition (polymer-ion-water) shifts, in a reversible way, by several orders of magnitude. Along with it several composition-dependent properties of the material change simultaneously. The reversible variation of the material volume driven by the reactions mimics the natural muscles behaviour: artificial polymeric muscles, or polymeric electrochemical actuators, based on this property are being developed. With the material composition the consumed energy change as a function thermal, chemical or mechanical conditions. This fact is used for the development of sensors and biosensors. The material volume and the material potential shift, simultaneously, during the reaction. Here the possibility to develop dual sensing-actuators is explored: two elements working concurrently in the same, physically uniform, device mimicking haptic muscles. In this thesis the electrochemical synthesis of thick polypyrrole/DBS films is described. The electrochemical behaviour of the polymer film, used as a self-supported electrode, is characterized assuming the exchange of cations during its oxidation/reduction. For the electrochemical characterization of biomimetic films of polypyrrole/DBS, different electrochemical techniques are used and under different experimental conditions with the view to understanding the sensing potentialities of the material reactions. The study and electrochemical characterization of the motion of pPy/DBS//tape bilayer bending actuators corroborates that the reaction is driven by the expulsion of cations from the conducting polymer to the electrolyte during oxidation and its entrance during reduction, in the full potential range studied. The actuator is a faradaic device controlled by the electrochemical reaction driving the movement: the rate of the angular movement is a linear function (easy control of the velocity) of the applied current and the described angle by the displacement is a linear function of the consumed charge (it also provides another easy control of the displacement). The evolution of the muscle potential and that of the consumed electrical energy during the reaction senses the energetic working conditions: chemical energy (electrolyte concentration), thermal energy (working temperature) or electric energy (applied current). The polymeric motor senses, while working, environmental conditions. The sensing calibration curves were attained for the different sensors. They have been constructed and characterized triple-layer artificial muscles pPy/DBS//Tape//pPy/DBS, corroborating again the exchange of cations during the reaction, the faradic nature of the device and the ability of the device to sense, while moving, its environmental working conditions mimicking natural haptic muscles. The actuator (current and charge) and sensing (muscle potential and involved energy) signals are simultaneously present in only two connecting wires, mimicking brain-muscle intercommunication. The study of polymeric materials with cationic and/or ionic exchange opens the possibility of working in a future, using also anion-exchange materials, to develop new soft, wet, biomimetic and multifunctional tools and robots. Ionic, chemical, thermal and mechanical signals can be transformed into electrical ones and the involved information is transported using just two wires, simplifying in that way their connection to computers: the design of devices and robots having them heralds a more efficient technology.

Anisotropically Swelling Gels Attained through Axis-Dependent Crosslinking of MOF Crystals.

PubMed

Ishiwata, Takumi; Kokado, Kenta; Sada, Kazuki

2017-03-01

Anisotropically deforming objects have attracted considerable interest for use in molecular machines and artificial muscles. Herein, we focus on a new approach based on the crystal crosslinking of organic ligands in a pillared-layer metal-organic framework (PLMOF). The approach involves the transformation from crosslinked PLMOF to polymer gels through hydrolysis of the coordination bonds between the organic ligands and metal ions, giving a network polymer that exhibits anisotropic swelling. The anisotropic monomer arrangement in the PLMOF underwent axis-dependent crosslinking to yield anisotropically swelling gels. Therefore, the crystal crosslinking of MOFs should be a useful method for creating actuators with designable deformation properties. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

OFO experimental techniques and preliminary conclusions - Is artificial gravity needed during prolonged weightlessness.

NASA Technical Reports Server (NTRS)

Gualtierotti, T.; Bracchi, F.

1972-01-01

The technique of single unit recording from body systems generating electrical pulses coherent with their basic function (CNS, muscles, sense organs) has been proved feasible during the OFO A orbital flight, an automatic physiological experiment. The results of recording 155 hours of orbital flight of pulses from the nerve fibres of four vestibular gravity sensors in two bull frogs indicate that the vestibular organ adjusts to zero g. As all the other biological changes observed during orbit are due to lack of exercise, it is concluded that artificial gravity might not be necessary during prolonged space missions or on low gravity celestial bodies.

Development of an artificial urethral valve using SMA actuators

NASA Astrophysics Data System (ADS)

Chonan, S.; Jiang, Z. W.; Tani, J.; Orikasa, S.; Tanahashi, Y.; Takagi, T.; Tanaka, M.; Tanikawa, J.

1997-08-01

The development of an artificial urethral valve for the treatment of urinary incontinence which occurs frequently in the aged is described. The prototype urethral valve is assembled in hand-drum form with four thin shape memory alloy (SMA) (nickel - titanium alloy) plates of 0.3 mm thickness. The shape memory effect in two directions is used to replace the urinary canal sphincter muscles and to control the canal opening and closing functions. The characteristic of the SMA is to assume the shape of a circular arc at normal temperatures and a flat shape at higher temperatures. Experiments have been conducted using a canine bladder and urinary canal.

Reflection of induced and amplified food motivation in impulse activity of the masticatory muscles during electrostimulation of the "hunger center" in the lateral hypothalamus in rabbits.

PubMed

Ignatova, J P; Kromin, A A

2012-04-01

We studied reflection of artificially induced and amplified food motivation in impulse activity of the masticatory muscles during electrostimulation of "hunger center" of the lateral hypothalamus in the absence and presence of food. The threshold stimulation of the lateral hypothalamus in hungry and satiated animals in the absence of food induced incessant food-procuring behavior paralleled by regular generation of spike bursts in masticatory muscles with biomodal distributions of intervals between pulses. This reaction of masticatory muscles during stimulation of the lateral hypothalamus in the absence of food was an example of the anticipatory reaction reflecting characteristics of the action result acceptor. Higher level of hunger motivation during threshold stimulation of the lateral hypothalamus in hungry and satiated rabbits in the course of effective food-procuring behavior increased the incidence of spike burst generation during the food capture phase, but did not modify this parameter during the chewing phase. Impulse activity of the masticatory muscles reflected convergent interactions of food motivation and support excitation on neurons of the central generator of chewing pattern.

Modeling and testing of a knitted-sleeve fluidic artificial muscle

NASA Astrophysics Data System (ADS)

Ball, Erick J.; Meller, Michael A.; Chipka, Jordan B.; Garcia, Ephrahim

2016-11-01

The knitted-sleeve fluidic muscle is similar in design to a traditional McKibben muscle, with a separate bladder and sleeve. However, in place of a braided sleeve, it uses a tubular-knit sleeve made from a thin strand of flexible but inextensible yarn. When the bladder is pressurized, the sleeve expands by letting the loops of fiber slide past each other, changing the dimensions of the rectangular cells in the stitch pattern. Ideally, the internal volume of the sleeve would reach a maximum when its length has contracted by 2/3 from its maximum length, and although this is not reachable in practice, preliminary tests show that free contraction greater than 50% is achievable. The motion relies on using a fiber with a low coefficient of friction in order to reduce hysteresis to an acceptable level. In addition to increased stroke length, potential advantages of this technique include slower force drop-off during the stroke, more useable energy in certain applications, and greater similarity to the force-length relationship of skeletal muscle. Its main limitation is its potentially greater effect from friction compared to other fluidic muscle designs.

Importance of nonverbal expression to the emergence of emotive artificial intelligence systems

NASA Astrophysics Data System (ADS)

Pioggia, Giovanni; Hanson, David; Dinelli, Serena; Di Francesco, Fabio; Francesconi, R.; De Rossi, Danilo

2002-07-01

The nonverbal expression of the emotions, especially in the human face, has rapidly become an area of intense interest in computer science and robotics. Exploring the emotions as a link between external events and behavioural responses, artificial intelligence designers and psychologists are approaching a theoretical understanding of foundational principles which will be key to the physical embodiment of artificial intelligence. In fact, it has been well demonstrated that many important aspects of intelligence are grounded in intimate communication with the physical world- so-called embodied intelligence . It follows naturally, then, that recent advances in emotive artificial intelligence show clear and undeniable broadening in the capacities of biologically-inspired robots to survive and thrive in a social environment. The means by which AI may express its foundling emotions are clearly integral to such capacities. In effect: powerful facial expressions are critical to the development of intelligent, sociable robots. Following discussion the importance of the nonverbal expression of emotions in humans and robots, this paper describes methods used in robotically emulating nonverbal expressions using human-like robotic faces. Furthermore, it describes the potentially revolutionary impact of electroactive polymer (EAP) actuators as artificial muscles for such robotic devices.

A solid-state dielectric elastomer switch for soft logic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chau, Nixon; Slipher, Geoffrey A., E-mail: geoffrey.a.slipher.civ@mail.mil; Mrozek, Randy A.

In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease ofmore » manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.« less

Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse.

PubMed

Reilly, Beau D; Hickey, Anthony J R; Cramp, Rebecca L; Franklin, Craig E

2014-04-01

Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility, aestivating animals exhibit little skeletal muscle atrophy compared with artificially immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After 4 months of aestivation, C. alboguttata had significantly depressed whole-body metabolism by ~70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely to reflect those in vivo. The percentage ROS released per O2 molecule consumed was also ~94% less at these concentrations, indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.

An artificial-intelligence technique for qualitatively deriving enzyme kinetic mechanisms from initial-velocity measurements and its application to hexokinase.

PubMed Central

Garfinkel, L; Cohen, D M; Soo, V W; Garfinkel, D; Kulikowski, C A

1989-01-01

We have developed a computer method based on artificial-intelligence techniques for qualitatively analysing steady-state initial-velocity enzyme kinetic data. We have applied our system to experiments on hexokinase from a variety of sources: yeast, ascites and muscle. Our system accepts qualitative stylized descriptions of experimental data, infers constraints from the observed data behaviour and then compares the experimentally inferred constraints with corresponding theoretical model-based constraints. It is desirable to have large data sets which include the results of a variety of experiments. Human intervention is needed to interpret non-kinetic information, differences in conditions, etc. Different strategies were used by the several experimenters whose data was studied to formulate mechanisms for their enzyme preparations, including different methods (product inhibitors or alternate substrates), different experimental protocols (monitoring enzyme activity differently), or different experimental conditions (temperature, pH or ionic strength). The different ordered and rapid-equilibrium mechanisms proposed by these experimenters were generally consistent with their data. On comparing the constraints derived from the several experimental data sets, they are found to be in much less disagreement than the mechanisms published, and some of the disagreement can be ascribed to different experimental conditions (especially ionic strength). PMID:2690819

Predicting body fat percentage based on gender, age and BMI by using artificial neural networks.

PubMed

Kupusinac, Aleksandar; Stokić, Edita; Doroslovački, Rade

2014-02-01

In the human body, the relation between fat and fat-free mass (muscles, bones etc.) is necessary for the diagnosis of obesity and prediction of its comorbidities. Numerous formulas, such as Deurenberg et al., Gallagher et al., Jackson and Pollock, Jackson et al. etc., are available to predict body fat percentage (BF%) from gender (GEN), age (AGE) and body mass index (BMI). These formulas are all fairly similar and widely applicable, since they provide an easy, low-cost and non-invasive prediction of BF%. This paper presents a program solution for predicting BF% based on artificial neural network (ANN). ANN training, validation and testing are done by randomly divided dataset that includes 2755 subjects: 1332 women (GEN = 0) and 1423 men (GEN = 1), with AGE from 18 to 88 y and BMI from 16.60 to 64.60 kg/m(2). BF% was estimated by using Tanita bioelectrical impedance measurements (Tanita Corporation, Tokyo, Japan). ANN inputs are: GEN, AGE and BMI, and output is BF%. The predictive accuracy of our solution is 80.43%. The main goal of this paper is to promote a new approach to predicting BF% that has same complexity and costs but higher predictive accuracy than above-mentioned formulas. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Advances in selective activation of muscles for non-invasive motor neuroprostheses.

PubMed

Koutsou, Aikaterini D; Moreno, Juan C; Del Ama, Antonio J; Rocon, Eduardo; Pons, José L

2016-06-13

Non-invasive neuroprosthetic (NP) technologies for movement compensation and rehabilitation remain with challenges for their clinical application. Two of those major challenges are selective activation of muscles and fatigue management. This review discusses how electrode arrays improve the efficiency and selectivity of functional electrical stimulation (FES) applied via transcutaneous electrodes. In this paper we review the principles and achievements during the last decade on techniques for artificial motor unit recruitment to improve the selective activation of muscles. We review the key factors affecting the outcome of muscle force production via multi-pad transcutaneous electrical stimulation and discuss how stimulation parameters can be set to optimize external activation of body segments. A detailed review of existing electrode array systems proposed by different research teams is also provided. Furthermore, a review of the targeted applications of existing electrode arrays for control of upper and lower limb NPs is provided. Eventually, last section demonstrates the potential of electrode arrays to overcome the major challenges of NPs for compensation and rehabilitation of patient-specific impairments.

Humanlike robots: the upcoming revolution in robotics

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph

2009-08-01

Humans have always sought to imitate the human appearance, functions and intelligence. Human-like robots, which for many years have been a science fiction, are increasingly becoming an engineering reality resulting from the many advances in biologically inspired technologies. These biomimetic technologies include artificial intelligence, artificial vision and hearing as well as artificial muscles, also known as electroactive polymers (EAP). Robots, such as the vacuum cleaner Rumba and the robotic lawnmower, that don't have human shape, are already finding growing use in homes worldwide. As opposed to other human-made machines and devices, this technology raises also various questions and concerns and they need to be addressed as the technology advances. These include the need to prevent accidents, deliberate harm, or their use in crime. In this paper the state-of-the-art of the ultimate goal of biomimetics, the development of humanlike robots, the potentials and the challenges are reviewed.

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system*

PubMed Central

Zan, Peng; Yang, Bang-hua; Shao, Yong; Yan, Guo-zheng; Liu, Hua

2010-01-01

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter. The coupling coils and human tissues, including the skin, fat, muscle, liver, and blood, were considered. Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model. First, SAR and current density as a function of frequency (10–107 Hz) for an emission current of 1.5 A were calculated under different tissue thickness. Then relations between SAR, current density, and five types of tissues under each frequency were deduced. As a result, both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The results show that the analysis of these data is very important for developing the artificial anal sphincter system. PMID:21121071

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system.

PubMed

Zan, Peng; Yang, Bang-hua; Shao, Yong; Yan, Guo-zheng; Liu, Hua

2010-12-01

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter. The coupling coils and human tissues, including the skin, fat, muscle, liver, and blood, were considered. Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model. First, SAR and current density as a function of frequency (10-10(7) Hz) for an emission current of 1.5 A were calculated under different tissue thickness. Then relations between SAR, current density, and five types of tissues under each frequency were deduced. As a result, both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The results show that the analysis of these data is very important for developing the artificial anal sphincter system.

Humanlike Robots - The Upcoming Revolution in Robotics

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2009-01-01

Humans have always sought to imitate the human appearance, functions and intelligence. Human-like robots, which for many years have been a science fiction, are increasingly becoming an engineering reality resulting from the many advances in biologically inspired technologies. These biomimetic technologies include artificial intelligence, artificial vision and hearing as well as artificial muscles, also known as electroactive polymers (EAP). Robots, such as the vacuum cleaner Rumba and the robotic lawnmower, that don't have human shape, are already finding growing use in homes worldwide. As opposed to other human-made machines and devices, this technology raises also various questions and concerns and they need to be addressed as the technology advances. These include the need to prevent accidents, deliberate harm, or their use in crime. In this paper the state-of-the-art of the ultimate goal of biomimetics, the development of humanlike robots, the potentials and the challenges are reviewed.

Development and Analysis of Bending Actuator Using McKibben Artificial Muscle

NASA Astrophysics Data System (ADS)

Zhao, Feifei; Dohta, Shujiro; Akagi, Tetsuya

Recent years, the number of nuclear families is rapidly growing. So the development of a human-friendly-robot which can take care of human daily life is strongly desired. This robot has to work just like a human, so, it is needed to have a dexterous soft hand in the robot. Therefore, we have developed an artificial soft gripper. This robot hand which has five fingers is made of silicone rubber. We also developed the hand which could be used to achieve several works just like a human hand. For example, it can grasp some objects that have the different shape and stiffness. Since it is made of silicone rubber, there is little damage to the object. However, the finger could not generate a larger force, less than 3N. In addition, it needs a skill and time to make the finger. In this study, we proposed and tested a bending actuator that could be easily constructed by putting the McKibben artificial muscle into the flexible tube. We also investigated the generated force and bending angle of the actuator. As a result, the generated force of the actuator was improved about 8.5 times as large as previous one. We also improved the bending actuator by changing the tube and the slit of the flexible tube. And the analytical model for the bending actuator was proposed and the calculated results were compared with the experimental ones.

Plasticity of the Muscle Stem Cell Microenvironment

PubMed Central

Dinulovic, Ivana; Furrer, Regula; Handschin, Christoph

2018-01-01

Satellite cells (SCs) are adult muscle stem cells capable of repairing damaged and creating new muscle tissue throughout life. Their functionality is tightly controlled by a microenvironment composed of a wide variety of factors, such as numerous secreted molecules and different cell types, including blood vessels, oxygen, hormones, motor neurons, immune cells, cytokines, fibroblasts, growth factors, myofibers, myofiber metabolism, the extracellular matrix and tissue stiffness. This complex niche controls SC biology – quiescence, activation, proliferation, differentiation or renewal and return to quiescence. In this review, we attempt to give a brief overview of the most important players in the niche and their mutual interaction with SCs. We address the importance of the niche to SC behavior under physiological and pathological conditions, and finally survey the significance of an artificial niche both for basic and translational research purposes. PMID:29204832

Temporal Taylor's scaling of facial electromyography and electrodermal activity in the course of emotional stimulation

NASA Astrophysics Data System (ADS)

Chołoniewski, Jan; Chmiel, Anna; Sienkiewicz, Julian; Hołyst, Janusz A.; Küster, Dennis; Kappas, Arvid

2016-09-01

High frequency psychophysiological data create a challenge for quantitative modeling based on Big Data tools since they reflect the complexity of processes taking place in human body and its responses to external events. Here we present studies of fluctuations in facial electromyography (fEMG) and electrodermal activity (EDA) massive time series and changes of such signals in the course of emotional stimulation. Zygomaticus major (ZYG, "smiling" muscle) activity, corrugator supercilii (COR, "frowning"bmuscle) activity, and phasic skin conductance (PHSC, sweating) levels of 65 participants were recorded during experiments that involved exposure to emotional stimuli (i.e., IAPS images, reading and writing messages on an artificial online discussion board). Temporal Taylor's fluctuations scaling were found when signals for various participants and during various types of emotional events were compared. Values of scaling exponents were close to 1, suggesting an external origin of system dynamics and/or strong interactions between system's basic elements (e.g., muscle fibres). Our statistical analysis shows that the scaling exponents enable identification of high valence and arousal levels in ZYG and COR signals.

Gaussian Process Autoregression for Simultaneous Proportional Multi-Modal Prosthetic Control With Natural Hand Kinematics.

PubMed

Xiloyannis, Michele; Gavriel, Constantinos; Thomik, Andreas A C; Faisal, A Aldo

2017-10-01

Matching the dexterity, versatility, and robustness of the human hand is still an unachieved goal in bionics, robotics, and neural engineering. A major limitation for hand prosthetics lies in the challenges of reliably decoding user intention from muscle signals when controlling complex robotic hands. Most of the commercially available prosthetic hands use muscle-related signals to decode a finite number of predefined motions and some offer proportional control of open/close movements of the whole hand. Here, in contrast, we aim to offer users flexible control of individual joints of their artificial hand. We propose a novel framework for decoding neural information that enables a user to independently control 11 joints of the hand in a continuous manner-much like we control our natural hands. Toward this end, we instructed six able-bodied subjects to perform everyday object manipulation tasks combining both dynamic, free movements (e.g., grasping) and isometric force tasks (e.g., squeezing). We recorded the electromyographic and mechanomyographic activities of five extrinsic muscles of the hand in the forearm, while simultaneously monitoring 11 joints of hand and fingers using a sensorized data glove that tracked the joints of the hand. Instead of learning just a direct mapping from current muscle activity to intended hand movement, we formulated a novel autoregressive approach that combines the context of previous hand movements with instantaneous muscle activity to predict future hand movements. Specifically, we evaluated a linear vector autoregressive moving average model with exogenous inputs and a novel Gaussian process ( ) autoregressive framework to learn the continuous mapping from hand joint dynamics and muscle activity to decode intended hand movement. Our approach achieves high levels of performance (RMSE of 8°/s and ). Crucially, we use a small set of sensors that allows us to control a larger set of independently actuated degrees of freedom of a hand. This novel undersensored control is enabled through the combination of nonlinear autoregressive continuous mapping between muscle activity and joint angles. The system evaluates the muscle signals in the context of previous natural hand movements. This enables us to resolve ambiguities in situations, where muscle signals alone cannot determine the correct action as we evaluate the muscle signals in their context of natural hand movements. autoregression is a particularly powerful approach which makes not only a prediction based on the context but also represents the associated uncertainty of its predictions, thus enabling the novel notion of risk-based control in neuroprosthetics. Our results suggest that autoregressive approaches with exogenous inputs lend themselves for natural, intuitive, and continuous control in neurotechnology, with the particular focus on prosthetic restoration of natural limb function, where high dexterity is required for complex movements.

The Amnioscope Strikes Back as a Useful Device for Pinhole Amniotomy in the Management of Polyhydramnios

PubMed Central

Koyama, Shinsuke; Tomimatsu, Takuji; Kanagawa, Takeshi; Tsutsui, Tateki; Kimura, Tadashi

2011-01-01

Polyhydramnios is associated with many serious maternal complications such as placental abruption or cord prolapse at rupture of membranes, uterine dysfunction at delivery, and postpartum hemorrhage. When considering uterine dysfunction caused by overstretched uterine muscles, active artificial amniotomy for more efficient labor seems to be a preferred obstetric management, but the potential adverse complications make obstetricians hesitate to perform this procedure. In such a challenging situation, a new strategy is required. We recently performed pinhole artificial amniotomy using an amnioscope in four women with polyhydramnios, not only to accelerate of labor but also to more slowly and safely reduce amniotic fluid volume. We had no complications using this procedure, and all women were able to have a vaginal delivery without postpartum hemorrhage and neonatal asphyxia. Pinhole artificial amniotomy using an amnioscope may be more convenient and safer than conventional artificial amniotomy. The significance of the amnioscope has been practically nil in modern obstetric management. In this pilot clinical study, we identified a new value for the amnioscope as a promising device for safer amniotomy in women with polyhydramnios. PMID:23705096

Referral of sensation to an advanced humanoid robotic hand prosthesis.

PubMed

Rosén, Birgitta; Ehrsson, H Henrik; Antfolk, Christian; Cipriani, Christian; Sebelius, Fredrik; Lundborg, Göran

2009-01-01

Hand prostheses that are currently available on the market are used by amputees to only a limited extent, partly because of lack of sensory feedback from the artificial hand. We report a pilot study that showed how amputees can experience a robot-like advanced hand prosthesis as part of their own body. We induced a perceptual illusion by which touch applied to the stump of the arm was experienced from the artificial hand. This illusion was elicited by applying synchronous tactile stimulation to the hidden amputation stump and the robotic hand prosthesis in full view. In five people who had had upper limb amputations this stimulation caused referral touch sensation from the stump to the artificial hand, and the prosthesis was experienced more like a real hand. We also showed that this illusion can work when the amputee controls the movements of the artificial hand by recordings of the arm muscle activity with electromyograms. These observations indicate that the previously described "rubber hand illusion" is also valid for an advanced hand prosthesis, even when it has a robotic-like appearance.

Micro- and nanostructured electro-active polymer actuators as smart muscles for incontinence treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osmani, Bekim, E-mail: bekim.osmani@unibas.ch, E-mail: tino.toepper@unibas.ch; Töpper, Tino, E-mail: bekim.osmani@unibas.ch, E-mail: tino.toepper@unibas.ch; Weiss, Florian M., E-mail: vanessa.leung@unibas.ch, E-mail: bert.mueller@unibas.ch

2015-02-17

Treatments of severe incontinence are currently based on purely mechanical systems that generally result in revision after three to five years. Our goal is to develop a prototype acting in a natural-analogue manner as artificial muscle, which is based on electro-active polymers. Dielectric actuators have outstanding performances including millisecond response times, mechanical strains of more than 10 % and power to mass densities similar to natural muscles. They basically consist of polymer films sandwiched between two compliant electrodes. The incompressible but elastic polymer film transduces the electrical energy into mechanical work according to the Maxwell pressure. Available polymer films aremore » micrometers thick and voltages as large as kV are necessary to obtain 10 % strain. For medical implants, polymer films should be nanometer thin to realize actuation below 48 V. The metallic electrodes have to be stretchable to follow the strain of 10 % and remain conductive. Recent results on the stress/strain behavior of anisotropic EAP-cantilevers have shown dependencies on metal electrode preparation. We have investigated tunable anisotropic micro- and nanostructures for metallic electrodes. They show a preferred actuation direction with improved stress-strain behavior. The bending of the cantilever has been characterized by the laser beam deflection method. The impact of the electrode on the effective Young's Modulus is measured using an Ultra Nanoindentation Tester with an integrated reference system for soft polymer surfaces. Once ten thousand layers of nanometer-thin EAP actuators are available, devices beyond the envisioned application will flood the market.« less

Contrast of artificial subcutaneous hematomas in MRI over time.

PubMed

Hassler, Eva Maria; Ogris, Kathrin; Petrovic, Andreas; Neumayer, Bernhard; Widek, Thomas; Yen, Kathrin; Scheurer, Eva

2015-03-01

In clinical forensic medicine, hematomas and other externally visible injuries build the basis for the reconstruction of events. However, dating of subcutaneous hematomas based on their external aspect is difficult. Magnetic resonance imaging (MRI) has proven its use in dating intracranial hemorrhage. Thus, the aim was to investigate if MRI can also be used for dating subcutaneous hematomas and to analyze an eventual influence of the hematoma shape. In 20 healthy volunteers (11 females, 9 males, aged 26.9 ± 3.8 years), 4 ml of autologous blood were injected subcutaneously in the thigh. The hematoma was scanned immediately after the injection, after 3 and 24 h and 3, 7, and 14 days using three sequences with different contrast. Data was analyzed by measuring signal intensities of the hematoma, the muscle, and the subcutaneous tissue over time, and the Michelson contrast coefficients between the tissues were calculated. In the analysis, hematoma shape was considered. Signal intensity of blood in the proton density-weighted sequence reached its maximum 3 h after the injection with a subsequent decrease, whereas the signal intensities of muscle and fatty tissue remained constant. The time course of the Michelson coefficient of blood versus muscle decreased exponentially with a change from hyperintensity to hypointensity at 116.9 h, depending on hematoma shape. In the other sequences, either variability was large or contrast coefficients stayed constant over time. The observed change of contrast of blood versus muscle permits a quick estimate of a hematoma's age. The consideration of the hematoma shape is expected to further enhance dating using MRI.

Modeling and control of a dielectric elastomer actuator

NASA Astrophysics Data System (ADS)

Gupta, Ujjaval; Gu, Guo-Ying; Zhu, Jian

2016-04-01

The emerging field of soft robotics offers the prospect of applying soft actuators as artificial muscles in the robots, replacing traditional actuators based on hard materials, such as electric motors, piezoceramic actuators, etc. Dielectric elastomers are one class of soft actuators, which can deform in response to voltage and can resemble biological muscles in the aspects of large deformation, high energy density and fast response. Recent research into dielectric elastomers has mainly focused on issues regarding mechanics, physics, material designs and mechanical designs, whereas less importance is given to the control of these soft actuators. Strong nonlinearities due to large deformation and electromechanical coupling make control of the dielectric elastomer actuators challenging. This paper investigates feed-forward control of a dielectric elastomer actuator by using a nonlinear dynamic model. The material and physical parameters in the model are identified by quasi-static and dynamic experiments. A feed-forward controller is developed based on this nonlinear dynamic model. Experimental evidence shows that this controller can control the soft actuator to track the desired trajectories effectively. The present study confirms that dielectric elastomer actuators are capable of being precisely controlled with the nonlinear dynamic model despite the presence of material nonlinearity and electromechanical coupling. It is expected that the reported results can promote the applications of dielectric elastomer actuators to soft robots or biomimetic robots.

The Effects of Partial Mechanical Loading and Ibandronate on Skeletal Tissues in the Adult Rat Hindquarter Suspension Model for Microgravity

NASA Technical Reports Server (NTRS)

Schultheis, Lester W.

1999-01-01

We report initial data from a suspended rat model that quantitatively relates chronic partial weightbearing to bone loss. Chronic partial weightbearing is our simulation of the effect of limited artificial gravity aboard spacecraft or reduced planetary gravity. Preliminary analysis of bone by PQCT, histomorphometry, mechanical testing and biochemistry suggest that chronic exposure to half of Earth gravity is insufficient to prevent severe bone loss. The effect of episodic full weightbearing activity (Earth Gravity) on rats otherwise at 50% weightbearing was also explored. This has similarity to treatment by an Earth G-rated centrifuge on a spacecraft that normally maintained artificial gravity at half of Earth G. Our preliminary evidence, using the above techniques to analyze bone, indicate that 2 hours daily of full weightbearing was insufficient to prevent the bone loss observed in 50% weightbearing animals. The effectiveness of partial weightbearing and episodic full weightbearing as potential countermeasures to bone loss in spaceflight was compared with treatment by ibandronate. Ibandronate, a long-acting potent bisphosphonate proved more effective in preventing bone loss and associated functionality based upon structure than our first efforts at mechanical countermeasures. The effectiveness of ibandronate was notable by each of the testing methods we used to study bone from gross structure and strength to tissue and biochemistry. These results appear to be independent of generalized systemic stress imposed by the suspension paradigm. Preliminary evidence does not suggest that blood levels of vitamin D were affected by our countermeasures. Despite the modest theraputic benefit of mechanical countermeasures of partial weightbearing and episodic full weightbearing, we know that some appropriate mechanical signal maintains bone mass in Earth gravity. Moreover, the only mechanism that correctly assigns bone mass and strength to oppose regionally specific force applied to bone is mechanical, a process based upon bone strain. Substantial evidence indicates that the specifics of dynamic loading i.e. time-varying forces are critical. Bone strain history is a predictor of the effect that mechanical conditions have on bone structure mass and strength. Using servo-controlled force plates on suspended rats with implanted strain gauges we manipulated impact forces of ambulation in the frequency (Fourier) domain. Our results indicate that high frequency components of impact forces are particularly potent in producing bone strain independent of the magnitude of the peak force or peak energy applied to the leg. Because a servo-system responds to forces produced by the rat's own muscle activity during ambulation, the direction of ground-reaction loads act on bone through the rat's own musculature. This is in distinction to passive vibration of the floor where forces reach bone through the natural filters of soft tissue and joints. Passive vibration may also be effective, but it may or may not increase bone in the appropriate architectural pattern to oppose the forces of normal ambulatory activity. Effectiveness of high frequency mechanical stimulation in producing regional (muscle directed) bone response will be limited by 1. the sensitivity of bone to a particular range of frequencies and 2. the inertia of the muscles, limiting their response to external forces by increasing tension along insertions. We have begun mathematical modeling of normal ambulatory activity. Effectiveness of high frequency mechanical stimulation in producing regional (muscle directed) bone response will be limited by 1. the sensitivity of bone to a particular range of frequencies and 2. the inertia of the muscles, limiting their response to external forces by increasing tension along insertions. We have begun mathematical modeling of the rat forelimb as a transfer function between impact force and bone strain to predict optimal dynamic loading conditions for this system. We plan additional studies of mechanical counter-measures that incorporate improved dynamic loading, features relevant to anticipated evaluation of artificial gravity, exercise regimens and exposure to Martian gravity, The combination of mechanical countermeasures with ibandronate will also be investigated for signs of synergy.

Effect of citric acid on the acidification of artificial pepsin solution for metacercariae isolation from fish.

PubMed

Kim, Min-Ki; Pyo, Kyoung-Ho; Hwang, Young-Sang; Chun, Hyang Sook; Park, Ki Hwan; Ko, Seong-Hee; Chai, Jong-Yil; Shin, Eun-Hee

2013-11-15

Artificial digestive solution based on pepsin is essential for collecting metacercariae from fish. To promote the enzymatic reactivity of pepsin, the pH of the solution has to be adjusted to pH 1.0-2.0. Hydrochloride (HCl) is usually used for this purpose, but the use of HCl raises safety concerns. The aim of this work was to address the usefulness of citric acid as an alternative for HCl for the acidification of pepsin solution, and to examine its potential to damage metacercariae during in vitro digestion as compared with HCl. Changes in pH after adding 1-9% of citric acid (m/v) to pepsin solution were compared to a 1% HCl (v/v) addition. Digestion of fish muscle was evaluated by measuring released protein concentrations by spectrophotometry. In addition, survival rates of metacercariae in pepsin solution were determined at different citric acid concentrations and were compared that of with 1% HCl. The present study shows that addition of citric acid reduced the pH of pepsin solutions to the required level. Addition of more than 5% of citric acid resulted in the effective digestion of fish muscle over 3h in vitro, and 5% citric acid was less lethal to metacercariae than 1% HCl in pepsin solution. Pepsin solution containing 5% citric acid had digestive capacity superior to pepsin solution containing 1% HCl after 3h incubation with released protein concentrations of 12.0 ng/ml for 5% citric acid and 9.6 ng/ml for 1% HCl. Accordingly, the present study suggests that the addition of 5% citric acid to pepsin solution is a good alternative to 1% HCl in infection studies because citric acid is a stable at room temperature and has a good safety profile. In addition, we suggest that the use of citric acid enables the preparation of commercial digestive solutions for the detection of microorganisms in fish and other vertebrate muscle tissue. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Expression of myostatin is not altered in lines of poultry exhibiting myofiber hyper- and hypoplasia.

PubMed

Mott, I; Ivarie, R

2002-06-01

Decades of selective breeding have yielded lines of poultry with substantial myofiber hyperplasia, vet little is known about what genes have been altered during the course of selection. Myostatin is a strong negative regulator of muscle mass in mice and cattle and could have been one of many genetic factors contributing to increased myofiber deposition in growth-selected lines of poultry. To test this hypothesis, the sequence and expression patterns of myostatin were analyzed in growth-selected lines of chickens and quail. The sequence of broiler myostatin cDNA, amplified via reverse transcription (RT)-PCR from embryonic muscle RNA, contained no missense mutations in the coding sequence when compared to that of White Leghorn layers, although two silent single nucleotide polymorphisms (SNP) were found. Northern analysis of myostatin transcripts from embryonic pectoralis and quadriceps showed no significant differences in expression levels between broiler and layer muscle RNA. However, levels of myostatin transcripts were greatly reduced in muscles of posthatch chicks compared to embryonic muscle. Myostatin protein was also present in broiler and layer embryonic muscle at similar levels. No significant polymorphisms or differences in RNA expression levels were found in embryonic muscles of divergently selected lines of Japanese quail. These results indicate that intense artificial selection in these growth-selected lines of poultry has neither silenced the expression of myostatin nor created null alleles via mutation in the lines analyzed.

Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo

PubMed Central

Rahe-Meyer, Niels; Pawlak, Matthias; Weilbach, Christian; Osthaus, Wilhelm Alexander; Ruhschulte, Hainer; Solomon, Cristina; Piepenbrock, Siegfried; Winterhalter, Michael

2008-01-01

Background The devices used for in vivo examination of muscle contractions assess only pure force contractions and the so-called isokinetic contractions. In isokinetic experiments, the extremity and its muscle are artificially moved with constant velocity by the measuring device, while a tetanic contraction is induced in the muscle, either by electrical stimulation or by maximal voluntary activation. With these systems, experiments cannot be performed at pre-defined, constant muscle length, single contractions cannot be evaluated individually and the separate examination of the isometric and the isotonic components of single contractions is not possible. Methods The myograph presented in our study has two newly developed technical units, i.e. a). a counterforce unit which can load the muscle with an adjustable, but constant force and b). a length-adjusting unit which allows for both the stretching and the contraction length to be infinitely adjustable independently of one another. The two units support the examination of complex types of contraction and store the counterforce and length-adjusting settings, so that these conditions may be accurately reapplied in later sessions. Results The measurement examples presented show that the muscle can be brought to every possible pre-stretching length and that single isotonic or complex isometric-isotonic contractions may be performed at every length. The applied forces act during different phases of contraction, resulting into different pre- and after-loads that can be kept constant – uninfluenced by the contraction. Maximal values for force, shortening, velocity and work may be obtained for individual muscles. This offers the possibility to obtain information on the muscle status and to monitor its changes under non-invasive measurement conditions. Conclusion With the Complex Myograph, the whole spectrum of a muscle's mechanical characteristics may be assessed. PMID:18616815

Actuators Based on Liquid Crystalline Elastomer Materials

PubMed Central

Jiang, Hongrui; Li, Chensha; Huang, Xuezhen

2013-01-01

Liquid crystalline elastomers (LCEs) exhibit a number of remarkable physical effects, including the unique, high-stroke reversible mechanical actuation when triggered by external stimuli. This article reviews some recent exciting developments in the field of LCEs materials with an emphasis on their utilization in actuator applications. Such applications include artificial muscles, industrial manufacturing, health and microelectromechanical systems (MEMS). With suitable synthetic and preparation pathways and well-controlled actuation stimuli, such as heat, light, electric and magnetic field, excellent physical properties of LCE materials can be realized. By comparing the actuating properties of different systems, general relationships between the structure and the property of LCEs are discussed. How these materials can be turned into usable devices using interdisciplinary techniques is also described. PMID:23648966

Actuators based on liquid crystalline elastomer materials

NASA Astrophysics Data System (ADS)

Jiang, Hongrui; Li, Chensha; Huang, Xuezhen

2013-05-01

Liquid crystalline elastomers (LCEs) exhibit a number of remarkable physical effects, including the unique, high-stroke reversible mechanical actuation when triggered by external stimuli. This article reviews some recent exciting developments in the field of LCE materials with an emphasis on their utilization in actuator applications. Such applications include artificial muscles, industrial manufacturing, health and microelectromechanical systems (MEMS). With suitable synthetic and preparation pathways and well-controlled actuation stimuli, such as heat, light, electric and magnetic fields, excellent physical properties of LCE materials can be realized. By comparing the actuating properties of different systems, general relationships between the structure and the properties of LCEs are discussed. How these materials can be turned into usable devices using interdisciplinary techniques is also described.

MEMS Based Micro Aerial Vehicles

NASA Astrophysics Data System (ADS)

Joshi, Niranjan; Köhler, Elof; Enoksson, Peter

2016-10-01

Designing a flapping wing insect robot requires understanding of insect flight mechanisms, wing kinematics and aerodynamic forces. These subsystems are interconnected and their dependence on one another affects the overall performance. Additionally it requires an artificial muscle like actuator and transmission to power the wings. Several kinds of actuators and mechanisms are candidates for this application with their own strengths and weaknesses. This article provides an overview of the insect scaled flight mechanism along with discussion of various methods to achieve the Micro Aerial Vehicle (MAV) flight. Ongoing projects in Chalmers is aimed at developing a low cost and low manufacturing time MAV. The MAV design considerations and design specifications are mentioned. The wings are manufactured using 3D printed carbon fiber and are under experimental study.

Characteristic analysis and experimental evaluation of artificial pneumatic cylinder

NASA Astrophysics Data System (ADS)

Kim, Dong-Soo; Bae, Sang-Kyu; Choi, Kyung-Hyun

2005-12-01

The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. Its features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was fabricated and tested. Finally, we compared the results between the test and the finite element analysis.

Motor unit recruitment during neuromuscular electrical stimulation: a critical appraisal.

PubMed

Bickel, C Scott; Gregory, Chris M; Dean, Jesse C

2011-10-01

Neuromuscular electrical stimulation (NMES) is commonly used in clinical settings to activate skeletal muscle in an effort to mimic voluntary contractions and enhance the rehabilitation of human skeletal muscles. It is also used as a tool in research to assess muscle performance and/or neuromuscular activation levels. However, there are fundamental differences between voluntary- and artificial-activation of motor units that need to be appreciated before NMES protocol design can be most effective. The unique effects of NMES have been attributed to several mechanisms, most notably, a reversal of the voluntary recruitment pattern that is known to occur during voluntary muscle contractions. This review outlines the assertion that electrical stimulation recruits motor units in a nonselective, spatially fixed, and temporally synchronous pattern. Additionally, it synthesizes the evidence that supports the contention that this recruitment pattern contributes to increased muscle fatigue when compared with voluntary actions and provides some commentary on the parameters of electrical stimulation as well as emerging technologies being developed to facilitate NMES implementation. A greater understanding of how electrical stimulation recruits motor units, as well as the benefits and limitations of its use, is highly relevant when using this tool for testing and training in rehabilitation, exercise, and/or research.

Carbon Nanotube Aluminum Matrix Composites

DTIC Science & Technology

2010-08-01

from nanoscale transistors (2) and interconnects (3), supercapacitors (4), artificial muscle fibers (5), and even as axles in molecular vehicles (6...anything other than basic architectures. This problem is compounded for nanomaterials such as CNTs, where homogeneous dispersion (not to mention any form...Microelectronic Engineering 2002, 64, 399–408. 4. Frackowiak, E.; Metenier, K.; Bertagna, V.; Beguin, F. Supercapacitor Electrodes From Multiwalled

Bionic Running for Unilateral Transtibial Military Amputees

DTIC Science & Technology

2010-01-01

Bellman, R., 2010, “An Active Ankle-Foot Prosthesis With Biomechanical Energy Regeneration”, Transactions of the ASME Journal...Lefeber, D., 2008, “A Biomechanical Transtibial Prosthesis Powered by Pleated Pneumatic Artificial Muscles,” Model Identification and Control, 4, 394- 405. ...Inc., have designed, built, and demonstrated a first of its kind motor powered, single board computer controlled, running prosthesis for military

Valve repair for traumatic tricuspid regurgitation.

PubMed

Maisano, F; Lorusso, R; Sandrelli, L; Torracca, L; Coletti, G; La Canna, G; Alfieri, O

1996-01-01

The review of six cases of valve repair for traumatic tricuspid regurgitation in our institution and 74 in the literature in order to assess effective methods of treating this lesion. Tricuspid valve regurgitation is a rare complication of blunt chest trauma. Optimal treatment for this condition is still controversial ranging from long-term medical therapy to early surgical correction. We followed the cases of six consecutive patients with post-traumatic tricuspid incompetence who were successfully treated with reparative techniques. All patients were male and their ages ranged from 18 years to 42 years. Valve regurgitation was always secondary to blunt chest trauma due to motor vehicle accident. The mechanism of valve insufficiency was invariably anterior leaflet prolapse due to chordal or papillary muscle rupture associated with annular dilatation. Surgical procedures included Carpentier ring implant (5 patients), Bex posterior annuloplasty (1 patient), implant of artificial chordae (4 patients), papillary muscle reinsertion (2 patients), commissuroplasty (1 patient) and "artificial double orifice" technique (1 patient). Tricuspid insufficiency improved in all patients after the correction. No complications were recorded and all patients were asymptomatic at the follow-up. Since post-traumatic tricuspid regurgitation is effectively correctable with reparative techniques, early operation is recommended to relieve symptoms and to prevent right ventricular dysfunction.

Soft Ultrathin Electronics Innervated Adaptive Fully Soft Robots.

PubMed

Wang, Chengjun; Sim, Kyoseung; Chen, Jin; Kim, Hojin; Rao, Zhoulyu; Li, Yuhang; Chen, Weiqiu; Song, Jizhou; Verduzco, Rafael; Yu, Cunjiang

2018-03-01

Soft robots outperform the conventional hard robots on significantly enhanced safety, adaptability, and complex motions. The development of fully soft robots, especially fully from smart soft materials to mimic soft animals, is still nascent. In addition, to date, existing soft robots cannot adapt themselves to the surrounding environment, i.e., sensing and adaptive motion or response, like animals. Here, compliant ultrathin sensing and actuating electronics innervated fully soft robots that can sense the environment and perform soft bodied crawling adaptively, mimicking an inchworm, are reported. The soft robots are constructed with actuators of open-mesh shaped ultrathin deformable heaters, sensors of single-crystal Si optoelectronic photodetectors, and thermally responsive artificial muscle of carbon-black-doped liquid-crystal elastomer (LCE-CB) nanocomposite. The results demonstrate that adaptive crawling locomotion can be realized through the conjugation of sensing and actuation, where the sensors sense the environment and actuators respond correspondingly to control the locomotion autonomously through regulating the deformation of LCE-CB bimorphs and the locomotion of the robots. The strategy of innervating soft sensing and actuating electronics with artificial muscles paves the way for the development of smart autonomous soft robots. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinematically stable bipedal locomotion using ionic polymer-metal composite actuators

NASA Astrophysics Data System (ADS)

Hosseinipour, Milad; Elahinia, Mohammad

2013-08-01

Ionic conducting polymer-metal composites (abbreviated as IPMCs) are interesting actuators that can act as artificial muscles in robotic and microelectromechanical systems. Various black or gray box models have modeled the electrochemical-mechanical behavior of these materials. In this study, the governing partial differential equation of the behavior of IPMCs is solved using finite element methods to find the critical actuation parameters, such as strain distribution, maximum strain, and response time. One-dimensional results of the FEM solution are then extended to 2D to find the tip displacement of a flap actuator and experimentally verified. A model of a seven-degree-of-freedom biped robot, actuated by IPMC flaps, is then introduced. The possibility of fast and stable bipedal locomotion using IPMC artificial muscles is the main motivation of this study. Considering the actuator limits, joint path trajectories are generated to achieve a fast and smooth motion. The stability of the proposed gait is then evaluated using the ZMP criterion and motion simulation. The fabrication parameters of each actuator, such as length, platinum plating thickness and installation angle, are then determined using the generated trajectories. A discussion on future studies on force-torque generation of IPMCs for biped locomotion concludes this paper.

On the thermodynamic and kinetic investigations of a [c2]daisy chain polymer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hmadeh, Mohamad; Fang, Lei; Trabolsi, Ali

2010-01-01

We report a variety of [c2]daisy chain molecules which undergo quantitative, efficient, and fully reversible molecular movements upon the addition of base/acid in organic solvents. Such externally triggered molecular movements can induce the contraction and extension of the [c2]daisy chain molecule as a whole. A linear polymer of such a bistable [c2]daisy chain exerts similar types of movements and can be looked upon as a candidate for the development of artificial muscles. The spectrophotometric investigations of both the monomeric and polymeric bistable [c2]daisy chains, as well as the corresponding model compounds, were performed in MeCN at room temperature, in ordermore » to obtain the thermodynamic parameters for these mechanically interlocked molecules. Based on their spectrophotometric and thermodynamic characteristics, kinetic analysis of the acid/base-induced contraction and extension of the [c2]daisy chain monomer and polymer were conducted by employing a stopped-flow technique. These kinetic data suggest that the rates of contraction and extension for these [c2]daisy chain molecules are determined by the thermodynamic stabilities of the corresponding kinetic intermediates. Faster switching rates for both the contraction and extension processes of the polymeric [c2]daisy chain were observed when compared to those of its monomeric counterpart. These kinetic and thermodynamic investigations on [c2]daisy chain-based muscle-like compounds provide important information for those seeking an understanding of the mechanisms of actuation in mechanically interlocked macromolecules.« less

Myasthenic Crisis Complicated with Myxedema, Positive for Both Anti-acetylcholine Receptor and Anti-muscle-specific Tyrosine Kinase Antibodies

PubMed Central

Horiuchi, Kazuhiro; Nagai, Azusa; Wakita, Masahiro; Ito, Shotaro; Takamura, Kei; Houzen, Hideki

2017-01-01

We herein report the case of myasthenic crisis occurring in a 51-year-old man. He had experienced ptosis, increased body weight with edema, and fatigue with dyspnea. He presented at our emergency department with disturbed consciousness. He was originally diagnosed with myxedema coma, and he required artificial respiration. Because his weakness persisted and he was positive for anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies, we diagnosed myasthenic crisis after various examinations. His clinical response to treatment was good and he was discharged in an ambulatory status 3 months after admission. This case demonstrates that myasthenic crisis may occur in association with myxedema. PMID:29093409

Myasthenic Crisis Complicated with Myxedema, Positive for Both Anti-acetylcholine Receptor and Anti-muscle-specific Tyrosine Kinase Antibodies.

PubMed

Horiuchi, Kazuhiro; Nagai, Azusa; Wakita, Masahiro; Ito, Shotaro; Takamura, Kei; Houzen, Hideki

2018-01-15

We herein report the case of myasthenic crisis occurring in a 51-year-old man. He had experienced ptosis, increased body weight with edema, and fatigue with dyspnea. He presented at our emergency department with disturbed consciousness. He was originally diagnosed with myxedema coma, and he required artificial respiration. Because his weakness persisted and he was positive for anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies, we diagnosed myasthenic crisis after various examinations. His clinical response to treatment was good and he was discharged in an ambulatory status 3 months after admission. This case demonstrates that myasthenic crisis may occur in association with myxedema.

[Influence of electrical stimulation of "hunger center" of the lateral hypothalamus and food reinforcements on myoelectrical activity of the gastro-esophageal sphincter and stomach in rabbits under the conditions of hunger and satiation].

PubMed

Kromin, A A; Zenina, O Iu

2013-01-01

To study the combined effect of electrostimulation of "hunger center" of the lateral hypothalamus (LH) and food-obtaining behavior arising from it on myoelectrical activity of gastro-esophageal sphincter (GES) and the stomach in pre-fed and subjected to food deprivation animals . MATERIAL AND METHODS. Registration of myoelectrical GES and the stomach activity was carried out under free-behavior conditions in rabbits subjected to food deprivation or pre-fed before the experiment. It was done by means of chronically implanted electrodes during LH electrostimulation in the presence of food. Simultaneously using the web-camera the animals behavior was recorded. LH stimulation was produced by STM-100C stimulator (USA) with implanted bipolar nichrome electrodes. Analysis of temporal parameters of myoelectrical activity of GES and the stomach were carried out by the program AcqKnowledge (USA), and statistical analysis of the data by the program Statistica 6. Significanse of differences between the samples was assessed by the U-Mann-Whitney test (p < 0.05). Electrostimulation of "hunger center" of the lateral hypothalamus in pre-fed rabbits and the rabbits subjected to daily food deprivation, in the presence of food causes resultant food behavior which is accompanied by regular generations of bursts of peak potentials, frequency of which is essentially different in hungry and satiated animals and depends on intensity of artificially induced and artificially reinforced food motivation. In the process of LH stimulation arising resultant food behavior in satiated animals is accompanied by regular generation of high-amplitude slow electrical waves (SEW) by the muscles of lesser curvature (LC), the body and antrum of the stomach (AS) and this is reflected in the structure of temporal organization of slow electrical activity (SEA) in the form of monomodal distributions of SEW periods, typical of satiation state. Despite the increase in food motivation level, due to LH stimulation, additional entry of food into the stomach of satiated rabbits completely eliminates inhibitory effect of starvational motivational excitation on SEA of the muscles of LC, the body and AS. SEA alterations of the stomach muscles in hungry rabbits in the presence of food and thus arising of food-obtaining behavior during LH stimulation have two-phase character. At the initial stage of food behavior in hungry animals during LH stimulation high extent of scaterring of the values of SEW periods generated by the body and AS muscles is preserved, as evidenced by the bimodal distribution of SEW periods characteristic of the state of hunger. In spite of food entry into the stomach at the 1-st phase of LH stimulation, inhibitory effect of artificially reinforced starvational motivational excitation on pacemaker activity of the stomach is retained. At the 2-nd phase of LH electrostimulation food reinforcement eliminates inhibitory effect of food motivational excitation on myoelectrical activity of pacemaker of the stomach that gives maximal rhythm of SEW generation to the body and AS, monomodal distributions of SEW periods indicate to it. lnteraction of artificially induced and artificially reinforced food motivational excitation with afferentation from food reinforcement on neurons of the central generator of deglutition pattern and dorsal vagal complex due to LH electrostimulation and thereby arising resultant food obtaining behavior is specifically reflected in patterns of myoelectrical activity of GES, LC, the body and AS.

On the viability of implantable electrodes for the natural control of artificial limbs: Review and discussion

PubMed Central

2012-01-01

The control of robotic prostheses based on pattern recognition algorithms is a widely studied subject that has shown promising results in acute experiments. The long-term implementation of this technology, however, has not yet been achieved due to practical issues that can be mainly attributed to the use of surface electrodes and their highly environmental dependency. This paper describes several implantable electrodes and discusses them as a solution for the natural control of artificial limbs. In this context “natural” is defined as producing control over limb movement analogous to that of an intact physiological system. This includes coordinated and simultaneous movements of different degrees of freedom. It also implies that the input signals must come from nerves or muscles that were originally meant to produce the intended movement and that feedback is perceived as originating in the missing limb without requiring burdensome levels of concentration. After scrutinizing different electrode designs and their clinical implementation, we concluded that the epimysial and cuff electrodes are currently promising candidates to achieving a long-term stable and natural control of robotic prosthetics, provided that communication from the electrodes to the outside of the body is guaranteed. PMID:22715940

Control of continuous phase PH using visible light to activate PH-dependent fibers and gels in a controlled and reversible manner

NASA Astrophysics Data System (ADS)

Zirino, Albert

1994-08-01

A transparent polyelectrolyte fiber or gel, such as crosslinked polyacrylic acid, which contracts and expands upon the addition of an acid or base to an aqueous medium solution, is placed in the same solution with a pH dependent dye, a colored photochromatic indicator dye. The dye preferably has a pAa value that is the same as the pH at a null contraction point of the fiber. By irradiating the solution with light of a wavelength of the absorption band of either the acid or base form of the dye, the solution pH is made to change, and the fiber is made to expand or contract, depending upon the wavelength. Thus, light energy is readily converted to work energy and may be used to power a pump, for example or an artificial muscle can be powered via an optical fiber.

High-performance, low-voltage, and easy-operable bending actuator based on aligned carbon nanotube/polymer composites.

PubMed

Chen, Luzhuo; Liu, Changhong; Liu, Ke; Meng, Chuizhou; Hu, Chunhua; Wang, Jiaping; Fan, Shoushan

2011-03-22

In this work, we show that embedding super-aligned carbon nanotube sheets into a polymer matrix (polydimethylsiloxane) can remarkably reduce the coefficient of thermal expansion of the polymer matrix by two orders of magnitude. Based on this unique phenomenon, we fabricated a new kind of bending actuator through a two-step method. The actuator is easily operable and can generate an exceptionally large bending actuation with controllable motion at very low driving DC voltages (<700 V/m). Furthermore, the actuator can be operated without electrolytes in the air, which is superior to conventional carbon nanotube actuators. Proposed electrothermal mechanism was discussed and confirmed by our experimental results. The exceptional bending actuation performance together with easy fabrication, low-voltage, and controllable motion demonstrates the potential ability of using this kind of actuator in various applicable areas, such as artificial muscles, microrobotics, microsensors, microtransducers, micromanipulation, microcantilever for medical applications, and so on.

Research Trends of Soft Actuators based on Electroactive Polymers and Conducting Polymers

NASA Astrophysics Data System (ADS)

Kaneto, K.

2016-04-01

Artificial muscles (or soft actuators) based on electroactive polymers (EAPs) are attractive power sources to drive human-like robots in place of electrical motor, because they are quiet, powerful, light weight and compact. Among EAPs for soft actuators, conducting polymers are superior in strain, stress, deformation form and driving voltage compared with the other EAPs. In this paper, the research trends of EAPs and conducting polymers are reviewed by retrieval of the papers and patents. The research activity of EAP actuators showed the maximum around 2010 and somehow declining now days. The reasons for the reducing activity are found to be partly due to problems of conducting polymer actuators for the practical application. The unique characteristics of conducting polymer actuators are mentioned in terms of the basic mechanisms of actuation, creeping, training effect and shape retention under high tensile loads. The issues and limitation of conducting polymer soft actuators are discussed.

Kirigami artificial muscles with complex biologically inspired morphologies

NASA Astrophysics Data System (ADS)

Sareh, Sina; Rossiter, Jonathan

2013-01-01

In this paper we present bio-inspired smart structures which exploit the actuation of flexible ionic polymer composites and the kirigami design principle. Kirigami design is used to convert planar actuators into active 3D structures capable of large out-of-plane displacement and that replicate biological mechanisms. Here we present the burstbot, a fluid control and propulsion mechanism based on the atrioventricular cuspid valve, and the vortibot, a spiral actuator based on Vorticella campanula, a ciliate protozoa. Models derived from biological counterparts are used as a platform for design optimization and actuator performance measurement. The symmetric and asymmetric fluid interactions of the burstbot are investigated and the effectiveness in fluid transport applications is demonstrated. The vortibot actuator is geometrically optimized as a camera positioner capable of 360° scanning. Experimental results for a one-turn spiral actuator show complex actuation derived from a single degree of freedom control signal.

Programmable and functional electrothermal bimorph actuators based on large-area anisotropic carbon nanotube paper

NASA Astrophysics Data System (ADS)

Li, Qingwei; Liu, Changhong; Fan, Shoushan

2018-04-01

Electro-active polymer (EAP) actuators, such as electronic, ionic and electrothermal (ET) actuators, have become an important branch of next-generation soft actuators in bionic robotics. However, most reported EAP actuators could realize only simple movements, being restricted by the small area of flexible electrodes and simple designs. We prepared large-area flexible electrodes of high anisotropy, made of oriented carbon nanotube (CNT) paper, and carried out artful graphic designs and processing on the electrodes to make functional ET bimorph actuators which can realize large bending deformations (over 220°, curvature > 1.5 cm-1) and bionic movements driven by electricity. The anisotropy of CNT paper benefits electrode designs and multiform actuations for complex actuators. Based on the large-area CNT paper, more interesting and functional actuators can be designed and prepared which will have practical applications in the fields of artificial muscles, complicated actuations, and soft and bionic robotics.

Artificial Muscle Devices: Innovations and Prospects for Fecal Incontinence Treatment.

PubMed

Fattorini, Elisa; Brusa, Tobia; Gingert, Christian; Hieber, Simone E; Leung, Vanessa; Osmani, Bekim; Dominietto, Marco D; Büchler, Philippe; Hetzer, Franc; Müller, Bert

2016-05-01

Fecal incontinence describes the involuntary loss of bowel content, which is responsible for stigmatization and social exclusion. It affects about 45% of retirement home residents and overall more than 12% of the adult population. Severe fecal incontinence can be treated by the implantation of an artificial sphincter. Currently available implants, however, are not part of everyday surgery due to long-term re-operation rates of 95% and definitive explantation rates of 40%. Such figures suggest that the implants fail to reproduce the capabilities of the natural sphincter. This article reviews the artificial sphincters on the market and under development, presents their physical principles of operation and critically analyzes their performance. We highlight the geometrical and mechanical parameters crucial for the design of an artificial fecal sphincter and propose more advanced mechanisms of action for a biomimetic device with sensory feedback. Dielectric electro-active polymer actuators are especially attractive because of their versatility, response time, reaction forces, and energy consumption. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence during daily activities.

Preliminary Study of a Novel Puborectalis-Like Artificial Anal Sphincter.

PubMed

Jin, Wentian; Yan, Guozheng; Wu, Hao; Lu, Shan; Zhou, Zerun

2017-09-01

Artificial anal sphincter (AAS) is an in situ implanted device that acts as a treatment for fecal incontinence regardless of etiology by augmenting the incompetent sphincteric structures. However, AAS is impeded from becoming a valid therapy by its high rate of ischemic complication and malfunction. This article presents an original puborectalis-like artificial anal sphincter (PAAS) that features a low risk of ischemia necrosis and rectal perception remodeling. The device retains continence by reproducing the action, including the pulling and angulating the rectum, of the puborectalis muscle, which forms the anorectal angle and reduces the required clamping pressure. Three rectal pressure sensors were embedded to maintain the pressure exerted on the rectal wall in a safe range and to monitor the distention of the rectum. A series of in vitro studies were conducted with a porcine rectum, and this PAAS prototype manifested the ability of maintaining continence with a clamping pressure considerably lower than that required by other AAS devices. The pressure sensors exhibit good linearity, and the function of rectal perception remodeling has also revealed high reliability with a success rate of 93.3%. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Computational Simulation on Facial Expressions and Experimental Tensile Strength for Silicone Rubber as Artificial Skin

NASA Astrophysics Data System (ADS)

Amijoyo Mochtar, Andi

2018-02-01

Applications of robotics have become important for human life in recent years. There are many specification of robots that have been improved and encriched with the technology advances. One of them are humanoid robot with facial expression which closer with the human facial expression naturally. The purpose of this research is to make computation on facial expressions and conduct the tensile strength for silicone rubber as artificial skin. Facial expressions were calculated by determining dimension, material properties, number of node elements, boundary condition, force condition, and analysis type. A Facial expression robot is determined by the direction and the magnitude external force on the driven point. The expression face of robot is identical with the human facial expression where the muscle structure in face according to the human face anatomy. For developing facial expression robots, facial action coding system (FACS) in approached due to follow expression human. The tensile strength is conducting due to check the proportional force of artificial skin that can be applied on the future of robot facial expression. Combining of calculated and experimental results can generate reliable and sustainable robot facial expression that using silicone rubber as artificial skin.

Restoration of orbicularis oculi muscle function in rabbits with peripheral facial paralysis via an implantable artificial facial nerve system

PubMed Central

Sun, Yajing; Jin, Cheng; Li, Keyong; Zhang, Qunfeng; Geng, Liang; Liu, Xundao; Zhang, Yi

2017-01-01

The purpose of the present study was to restore orbicularis oculi muscle function using the implantable artificial facial nerve system (IAFNS). The in vivo part of the IAFNS was implanted into 12 rabbits that were facially paralyzed on the right side of the face to restore the function of the orbicularis oculi muscle, which was indicated by closure of the paralyzed eye when the contralateral side was closed. Wireless communication links were established between the in vivo part (the processing chip and microelectrode) and the external part (System Controller program) of the system, which were used to set the working parameters and indicate the working state of the processing chip and microelectrode implanted in the body. A disturbance field strength test of the IAFNS processing chip was performed in a magnetic field dark room to test its electromagnetic radiation safety. Test distances investigated were 0, 1, 3 and 10 m, and levels of radiation intensity were evaluated in the horizontal and vertical planes. Anti-interference experiments were performed to test the stability of the processing chip under the interference of electromagnetic radiation. The fully implanted IAFNS was run for 5 h per day for 30 consecutive days to evaluate the accuracy and precision as well as the long-term stability and effectiveness of wireless communication. The stimulus intensity (range, 0–8 mA) was set every 3 days to confirm the minimum stimulation intensity which could indicate the movement of the paralyzed side was set. Effective stimulation rate was also tested by comparing the number of eye-close movements on both sides. The results of the present study indicated that the IAFNS could rebuild the reflex arc, inducing the experimental rabbits to close the eye of the paralyzed side. The System Controller program was able to reflect the in vivo part of the artificial facial nerve system in real-time and adjust the working pattern, stimulation intensity and frequency, range of wave and stimulation time. No significant differences in the stimulus intensities were observed during 30 days. The artificial facial nerve system chip operation stable in the anti-interference test, and the radiation field strength of the system was in a safe range according to the national standard. The IAFNS functioned without any interference and was able to restore functionality to facially paralyzed rabbits over the course of 30 days. PMID:29285055

Artificial Muscle (AM) Cilia Array for Underwater Systems

DTIC Science & Technology

2016-12-15

structures, including cilia-like structures. Specifically, a custom 3D printer was created that utilizes custom-made Nafion filament for 30 printing of custom... printing ) of IPMC material to create custom-shaped AM structures, including cilia-like structures. Various custom-shaped AM structures were fabricated via...integrating square cross-section IPMC actuators with a printed circuit board power delivery system. IV. Concise Accomplishments Performance

Wireless power transfer for a pacemaker application.

PubMed

Vulfin, Vladimir; Sayfan-Altman, Shai; Ianconescu, Reuven

2017-05-01

An artificial pacemaker is a small medical device that uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. The pacemaker is implanted under the skin, and uses for many years regular non-rechargeable batteries. However, the demand for rechargeable batteries in pacemakers increased, and the aim of this work is to design an efficient charging system for pacemakers.

Stacking Nematic Elastomers for Artificial Muscle Applications

DTIC Science & Technology

2006-04-01

nematic to isotropic phase transition. In this eport, a new approach is introduced by layering liquid crystal elastomer films to create thermally...actuated stacks. A heating element and thermally onductive grease embedded between elastomer films provide a means for rapid internal heat application...voltage application, stacks composed f two 100 m-thick films and a single heating element produce 18% strain between contracted and relaxed states. In

Application of cell co-culture system to study fat and muscle cells.

PubMed

Pandurangan, Muthuraman; Hwang, Inho

2014-09-01

Animal cell culture is a highly complex process, in which cells are grown under specific conditions. The growth and development of these cells is a highly unnatural process in vitro condition. Cells are removed from animal tissues and artificially cultured in various culture vessels. Vitamins, minerals, and serum growth factors are supplied to maintain cell viability. Obtaining result homogeneity of in vitro and in vivo experiments is rare, because their structure and function are different. Living tissues have highly ordered complex architecture and are three-dimensional (3D) in structure. The interaction between adjacent cell types is quite distinct from the in vitro cell culture, which is usually two-dimensional (2D). Co-culture systems are studied to analyze the interactions between the two different cell types. The muscle and fat co-culture system is useful in addressing several questions related to muscle modeling, muscle degeneration, apoptosis, and muscle regeneration. Co-culture of C2C12 and 3T3-L1 cells could be a useful diagnostic tool to understand the muscle and fat formation in animals. Even though, co-culture systems have certain limitations, they provide a more realistic 3D view and information than the individual cell culture system. It is suggested that co-culture systems are useful in evaluating the intercellular communication and composition of two different cell types.

An Artificial Tendon with Durable Muscle Interface

PubMed Central

Melvin, Alan; Litsky, Alan; Mayerson, Joel; Witte, David; Melvin, David; Juncosa-Melvin, Natalia

2010-01-01

A coupling mechanism that can permanently fix a forcefully contracting muscle to a bone anchor or any totally inert prosthesis would meet a serious need in orthopaedics. Our group developed the OrthoCoupler™ device to satisfy these demands. The objective of this study was to test OrthoCoupler’s performance in vitro and in vivo in the goat semitendinosus tendon model. For in vitro evaluation, 40 samples were fatigue-tested, cycling at 10 load levels, n=4 each. For in vivo evaluation, the semitendinosus tendon was removed bilaterally in 8 goats. Left sides were reattached with an OrthoCoupler, and right sides were reattached using the Krackow stitch with #5 braided polyester sutures. Specimens were harvested 60 days post-surgery and assigned for biomechanics and histology. Fatigue strength of the devices in vitro was several times the contractile force of the semitendinosus muscle. The in vivo devices were built equivalent to two of the in vitro devices, providing an additional safety factor. In strength testing at necropsy, suture controls pulled out at 120.5 ± 68.3 N, whereas each OrthoCoupler was still holding after the muscle tore, remotely, at 298±111.3N (mean ± SD)(p<0.0003). Muscle tear strength was reached with the fiber-muscle composite produced in healing still soundly intact. This technology may be of value for orthopaedic challenges in oncology, revision arthroplasty, tendon transfer, and sports-injury reconstruction. PMID:19639642

Automated muscle wrapping using finite element contact detection.

PubMed

Favre, Philippe; Gerber, Christian; Snedeker, Jess G

2010-07-20

Realistic muscle path representation is essential to musculoskeletal modeling of joint function. Algorithms predicting these muscle paths typically rely on a labor intensive predefinition of via points or underlying geometries to guide wrapping for given joint positions. While muscle wrapping using anatomically precise three-dimensional (3D) finite element (FE) models of bone and muscle has been achieved, computational expense and pre-processing associated with this approach exclude its use in applications such as subject-specific modeling. With the intention of combining advantageous features of both approaches, an intermediate technique relying on contact detection capabilities of commercial FE packages is presented. We applied the approach to the glenohumeral joint, and validated the method by comparison against existing experimental data. Individual muscles were modeled as a straight series of deformable beam elements and bones as anatomically precise 3D rigid bodies. Only the attachment locations and a default orientation of the undeformed muscle segment were pre-defined. The joint was then oriented in a static position of interest. The muscle segment free end was then moved along the shortest Euclidean path to its origin on the scapula, wrapping the muscle along bone surfaces by relying on software contact detection. After wrapping for a given position, the resulting moment arm was computed as the perpendicular distance from the line of action vector to the humeral head center of rotation. This approach reasonably predicted muscle length and moment arm for 27 muscle segments when compared to experimental measurements over a wide range of shoulder motion. Artificial via points or underlying contact geometries were avoided, contact detection and multiobject wrapping on the bone surfaces were automatic, and low computational cost permitted wrapping of individual muscles within seconds on a standard desktop PC. These advantages may be valuable for both general and subject-specific musculoskeletal modeling. 2010 Elsevier Ltd. All rights reserved.

A Novel Intronic Single Nucleotide Polymorphism in the Myosin heavy polypeptide 4 Gene Is Responsible for the Mini-Muscle Phenotype Characterized by Major Reduction in Hind-Limb Muscle Mass in Mice

PubMed Central

Kelly, Scott A.; Bell, Timothy A.; Selitsky, Sara R.; Buus, Ryan J.; Hua, Kunjie; Weinstock, George M.; Garland, Theodore; Pardo-Manuel de Villena, Fernando; Pomp, Daniel

2013-01-01

Replicated artificial selection for high levels of voluntary wheel running in an outbred strain of mice favored an autosomal recessive allele whose primary phenotypic effect is a 50% reduction in hind-limb muscle mass. Within the High Runner (HR) lines of mice, the numerous pleiotropic effects (e.g., larger hearts, reduced total body mass and fat mass, longer hind-limb bones) of this hypothesized adaptive allele include functional characteristics that facilitate high levels of voluntary wheel running (e.g., doubling of mass-specific muscle aerobic capacity, increased fatigue resistance of isolated muscles, longer hind-limb bones). Previously, we created a backcross population suitable for mapping the responsible locus. We phenotypically characterized the population and mapped the Minimsc locus to a 2.6-Mb interval on MMU11, a region containing ∼100 known or predicted genes. Here, we present a novel strategy to identify the genetic variant causing the mini-muscle phenotype. Using high-density genotyping and whole-genome sequencing of key backcross individuals and HR mice with and without the mini-muscle mutation, from both recent and historical generations of the HR lines, we show that a SNP representing a C-to-T transition located in a 709-bp intron between exons 11 and 12 of the Myosin heavy polypeptide 4 (Myh4) skeletal muscle gene (position 67,244,850 on MMU11; assembly, December 2011, GRCm38/mm10; ENSMUSG00000057003) is responsible for the mini-muscle phenotype, Myh4Minimsc. Using next-generation sequencing, our approach can be extended to identify causative mutations arising in mouse inbred lines and thus offers a great avenue to overcome one of the most challenging steps in quantitative genetics. PMID:24056412

A novel intronic single nucleotide polymorphism in the myosin heavy polypeptide 4 gene is responsible for the mini-muscle phenotype characterized by major reduction in hind-limb muscle mass in mice.

PubMed

Kelly, Scott A; Bell, Timothy A; Selitsky, Sara R; Buus, Ryan J; Hua, Kunjie; Weinstock, George M; Garland, Theodore; Pardo-Manuel de Villena, Fernando; Pomp, Daniel

2013-12-01

Replicated artificial selection for high levels of voluntary wheel running in an outbred strain of mice favored an autosomal recessive allele whose primary phenotypic effect is a 50% reduction in hind-limb muscle mass. Within the High Runner (HR) lines of mice, the numerous pleiotropic effects (e.g., larger hearts, reduced total body mass and fat mass, longer hind-limb bones) of this hypothesized adaptive allele include functional characteristics that facilitate high levels of voluntary wheel running (e.g., doubling of mass-specific muscle aerobic capacity, increased fatigue resistance of isolated muscles, longer hind-limb bones). Previously, we created a backcross population suitable for mapping the responsible locus. We phenotypically characterized the population and mapped the Minimsc locus to a 2.6-Mb interval on MMU11, a region containing ∼100 known or predicted genes. Here, we present a novel strategy to identify the genetic variant causing the mini-muscle phenotype. Using high-density genotyping and whole-genome sequencing of key backcross individuals and HR mice with and without the mini-muscle mutation, from both recent and historical generations of the HR lines, we show that a SNP representing a C-to-T transition located in a 709-bp intron between exons 11 and 12 of the Myosin heavy polypeptide 4 (Myh4) skeletal muscle gene (position 67,244,850 on MMU11; assembly, December 2011, GRCm38/mm10; ENSMUSG00000057003) is responsible for the mini-muscle phenotype, Myh4(Minimsc). Using next-generation sequencing, our approach can be extended to identify causative mutations arising in mouse inbred lines and thus offers a great avenue to overcome one of the most challenging steps in quantitative genetics.

Artificial embolization of carotid-cavernous fistula with post-operative patency of internal carotid artery

PubMed Central

Isamat, Fabian; Salleras, V.; Miranda, A. M.

1970-01-01

This report deals with a patient of 86 who developed a carotid-cavernous fistula. Artificial embolization alone was considered the safest treatment for this patient and proved to be adequate. Post-operative preservation of the patency of the internal carotid artery was demonstrated by angiography. We believe this method is particularly appropriate for carotid-cavernous fistulas if it is demonstrated by angiography that the major blood flow of the carotid artery pours into the fistula. A soft-iron clip attached to the muscle can be used for external and forceful guidance of the embolus into the fistula with the help of an electromagnet, hence the patency of the internal carotid artery can be preserved. The embolus should be introduced through the external carotid artery. This is the only case known to us in which patency of the internal carotid artery was post-operatively maintained. We have reviewed 545 reported cases of surgically treated carotid-cavernous fistulas and analysed the results from simple cervical carotid ligation to the more sophisticated methods of artificial embolizations. The results obtained by artificial embolization have been consistently good, while the other techniques have failed in large percentages. Artificial embolization should be used as the primary treatment for carotid-cavernous fistula, since ligation of the internal carotid artery precludes its embolization at a later date. Images PMID:5478949

Biologically inspired robots as artificial inspectors

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph

2002-06-01

Imagine an inspector conducting an NDE on an aircraft where you notice something is different about him - he is not real but rather he is a robot. Your first reaction would probably be to say 'it's unbelievable but he looks real' just as you would react to an artificial flower that is a good imitation. This science fiction scenario could become a reality at the trend in the development of biologically inspired technologies, and terms like artificial intelligence, artificial muscles, artificial vision and numerous others are increasingly becoming common engineering tools. For many years, the trend has been to automate processes in order to increase the efficiency of performing redundant tasks where various systems have been developed to deal with specific production line requirements. Realizing that some parts are too complex or delicate to handle in small quantities with a simple automatic system, robotic mechanisms were developed. Aircraft inspection has benefitted from this evolving technology where manipulators and crawlers are developed for rapid and reliable inspection. Advancement in robotics towards making them autonomous and possibly look like human, can potentially address the need to inspect structures that are beyond the capability of today's technology with configuration that are not predetermined. The operation of these robots may take place at harsh or hazardous environments that are too dangerous for human presence. Making such robots is becoming increasingly feasible and in this paper the state of the art will be reviewed.

Controlled flight of a biologically inspired, insect-scale robot.

PubMed

Ma, Kevin Y; Chirarattananon, Pakpong; Fuller, Sawyer B; Wood, Robert J

2013-05-03

Flies are among the most agile flying creatures on Earth. To mimic this aerial prowess in a similarly sized robot requires tiny, high-efficiency mechanical components that pose miniaturization challenges governed by force-scaling laws, suggesting unconventional solutions for propulsion, actuation, and manufacturing. To this end, we developed high-power-density piezoelectric flight muscles and a manufacturing methodology capable of rapidly prototyping articulated, flexure-based sub-millimeter mechanisms. We built an 80-milligram, insect-scale, flapping-wing robot modeled loosely on the morphology of flies. Using a modular approach to flight control that relies on limited information about the robot's dynamics, we demonstrated tethered but unconstrained stable hovering and basic controlled flight maneuvers. The result validates a sufficient suite of innovations for achieving artificial, insect-like flight.

Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays

NASA Astrophysics Data System (ADS)

Lu, S. G.; Chen, X.; Levard, T.; Diglio, P. J.; Gorny, L. J.; Rahn, C. D.; Zhang, Q. M.

2015-06-01

Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly.

Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays.

PubMed

Lu, S G; Chen, X; Levard, T; Diglio, P J; Gorny, L J; Rahn, C D; Zhang, Q M

2015-06-16

Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly.

Creating a Reinforcement Learning Controller for Functional Electrical Stimulation of a Human Arm*

PubMed Central

Thomas, Philip S.; Branicky, Michael; van den Bogert, Antonie; Jagodnik, Kathleen

2010-01-01

Clinical tests have shown that the dynamics of a human arm, controlled using Functional Electrical Stimulation (FES), can vary significantly between and during trials. In this paper, we study the application of Reinforcement Learning to create a controller that can adapt to these changing dynamics of a human arm. Development and tests were done in simulation using a two-dimensional arm model and Hill-based muscle dynamics. An actor-critic architecture is used with artificial neural networks for both the actor and the critic. We begin by training it using a Proportional Derivative (PD) controller as a supervisor. We then make clinically relevant changes to the dynamics of the arm and test the actor-critic’s ability to adapt without supervision in a reasonable number of episodes. PMID:22081795

Electrically stimulated signals from a long-term Regenerative Peripheral Nerve Interface.

PubMed

Langhals, Nicholas B; Woo, Shoshana L; Moon, Jana D; Larson, John V; Leach, Michelle K; Cederna, Paul S; Urbanchek, Melanie G

2014-01-01

Despite modern technological advances, the most widely available prostheses provide little functional recovery beyond basic grasping. Although sophisticated upper extremity prostheses are available, optimal prosthetic interfaces which give patients high-fidelity control of these artificial limbs are limited. We have developed a novel Regenerative Peripheral Nerve Interface (RPNI), which consists of a unit of free muscle that has been neurotized by a transected peripheral nerve. In conjunction with a biocompatible electrode on the muscle surface, the RPNI facilitates signal transduction from a residual peripheral nerve to a neuroprosthetic limb. The purpose of this study was to explore signal quality and reliability in an RPNI following an extended period of implantation. Following a 14-month maturation period, electromyographic signal generation was evaluated via electrical stimulation of the innervating nerve. The long-term RPNI was viable and healthy, as demonstrated by evoked compound muscle action potentials as well as histological tissue analysis. Signals exceeding 4 mV were successfully acquired and amplitudes were consistent across multiple repetitions of applied stimuli. There were no evident signs of muscle denervation, significant scar tissue, or muscle necrosis. This study provides further evidence that after a maturation period exceeding 1 year, reliable and consistent signals can still be acquired from an RPNI.

Decoding Lower Limb Muscle Activity and Kinematics from Cortical Neural Spike Trains during Monkey Performing Stand and Squat Movements

PubMed Central

Ma, Xuan; Ma, Chaolin; Huang, Jian; Zhang, Peng; Xu, Jiang; He, Jiping

2017-01-01

Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1). Two monkeys were used in this study. Subdermal intramuscular EMG electrodes were implanted to 8 right leg/thigh muscles. With ample data collected from neurons from a large brain area, we performed a spike triggered average (SpTA) analysis and got a series of density contours which revealed the spatial distributions of different muscle-innervating neurons corresponding to each given muscle. Based on the guidance of these results, we identified the locations optimal for chronic electrode implantation and subsequently carried on chronic neural data recordings. A recursive Bayesian estimation framework was proposed for decoding EMG signals together with kinematics from M1 spike trains. Two specific algorithms were implemented: a standard Kalman filter and an unscented Kalman filter. For the latter one, an artificial neural network was incorporated to deal with the nonlinearity in neural tuning. High correlation coefficient and signal to noise ratio between the predicted and the actual data were achieved for both EMG signals and kinematics on both monkeys. Higher decoding accuracy and faster convergence rate could be achieved with the unscented Kalman filter. These results demonstrate that lower limb EMG signals and kinematics during monkey stand/squat can be accurately decoded from a group of M1 neurons with the proposed algorithms. Our findings provide new insights for extending current BMI design concepts and techniques on upper limbs to lower limb circumstances. Brain controlled exoskeleton, prostheses or neuromuscular electrical stimulators for lower limbs are expected to be developed, which enables the subject to manipulate complex biomechatronic devices with mind in more harmonized manner. PMID:28223914

Semi-Autonomous Control with Cyber-Pain for Artificial Muscles and Smart Structures

DTIC Science & Technology

2010-09-15

avoid some key failure modes. Our approach has built on our developments in dynamic self-sensing and realistic simulation of DEA electromechanics...local controller) to avoid some key failure modes. Our approach has built on our developments in dynamic self-sensing and realistic simulation of DEA...strains [4]. In its natural state long polymer backbones are entangled with intermittent cross-links tying neighbouring backbones together. The soft

Future Soldiers: Analysis of Entry-Level Performance Requirements and Their Predictors

DTIC Science & Technology

2005-09-01

these future missions; "* New technology such as weapons, tools, and vehicles (e.g., robotics ) and the effect of technological change on personnel...Clusters 1. Close Combat 2. Non Line-of-Sight Fire 3. Surveillance, Intelligence, and Communications 4. Unmanned Vehicle/ Robotics Operator 5. Security...minimized with (a) new materials for ballistic protection, (b) new lethalities, and (c) exoskeletons /artificial muscles. • Infantrymen will experience better

Proceedings of the Workshop on Mobility and Control in Challenging Environments

DTIC Science & Technology

2007-09-20

1.18 h (V) -3.48 Electronic Nervous Systems Activating Nitinol With Electronic Neurons Controlling Walking With EN Networks ele dep prot ret forward...command backward command Myomorphic Actuators •Artificial Muscle Nitinol : 50/50 Alloy of Nickel and Titanium. • Two stable crystalline states • State...an electrical current through it causing conversion to austenite and shorteningText Kevlar “Tendon” Crimp Connector Teflon Coated Nitinol Current

Analysis of current density and specific absorption rate in biological tissue surrounding transcutaneous transformer for an artificial heart.

PubMed

Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

2008-01-01

This paper reports on the current density and specific absorption rate (SAR) analysis of biological tissue surrounding an air-core transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue is analyzed by the transmission line modeling method, and the current density and SAR as a function of frequency, output voltage, output power, and coil dimension are calculated. The biological tissue of the model has three layers including the skin, fat, and muscle. The results of simulation analysis show SARs to be very small at any given transmission conditions, about 2-14 mW/kg, compared to the basic restrictions of the International Commission on nonionizing radiation protection (ICNIRP; 2 W/kg), while the current density divided by the ICNIRP's basic restrictions gets smaller as the frequency rises and the output voltage falls. It is possible to transfer energy below the ICNIRP's basic restrictions when the frequency is over 250 kHz and the output voltage is under 24 V. Also, the parts of the biological tissue that maximized the current density differ by frequencies; in the low frequency is muscle and in the high frequency is skin. The boundary is in the vicinity of the frequency 600-1000 kHz.

Analysis of current density and specific absorption rate in biological tissue surrounding an air-core type of transcutaneous transformer for an artificial heart.

PubMed

Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

2006-01-01

This paper reports on the specific absorption rate (SAR) and the current density analysis of biological tissue surrounding an air-core type of transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue surrounding the transformer was analyzed by the transmission-line modeling method, and the SAR and current density as a function of frequency (200k-1 MHz) for a transcutaneous transmission of 20 W were calculated. The model's biological tissue has three layers including the skin, fat and muscle. As a result, the SAR in the vicinity of the transformer is sufficiently small and the normalized SAR value, which is divided by the ICNIRP's basic restriction, is 7 x 10(-3) or less. On the contrary, the current density is slightly in excess of the ICNIRP's basic restrictions as the frequency falls and the output voltage rises. Normalized current density is from 0.2 to 1.2. In addition, the layer in which the current's density is maximized depends on the frequency, the muscle in the low frequency (<700 kHz) and the skin in the high frequency (>700 kHz). The result shows that precision analysis taking into account the biological properties is very important for developing the transcutaneous transformer for TAH.

PVC gel soft actuator-based wearable assist wear for hip joint support during walking

NASA Astrophysics Data System (ADS)

Li, Yi; Hashimoto, Minoru

2017-12-01

Plasticized polyvinyl chloride (PVC) gel and mesh electrode-based soft actuators have considerable potential to provide new types of artificial muscle, exhibiting similar responsiveness to biological muscle in air, >10% deformation, >90 kPa output stress, variable stiffness, long cycle life (>5 million cycles), and low power consumption. We have designed and fabricated a prototype of walking assist wear using the PVC gel actuator in previous study. The system has several advantages compared with traditional motor-based exoskeletons, including lower weight and power consumption, and no requirement for rigid external structures that constrain the wearer’s joints. In this study, we designed and established a control and power system to making the whole system portable and wearable outdoors. And we designed two control strategies based on the characteristics of the assist wear and the biological kinematics. In a preliminary experimental evaluation, a hemiparetic stroke patient performed a 10 m to-and-fro straight line walking task with and without assist wear on the affected side. We found that the assist wear enabled natural movement, increasing step length and decreasing muscular activity during straight line walking. We demonstrated that the assistance effect could be adjusted by controlling the on-off time of the PVC gel soft actuators. The results show the effectiveness of the proposed system and suggest the feasibility of PVC gel soft actuators for developing practical soft wearable assistive devices, informing the development of future wearable robots and the other soft actuator technologies for human movement assistance and rehabilitation.

Artificial gravity as a countermeasure in long-duration space flight

NASA Technical Reports Server (NTRS)

Lackner, J. R.; DiZio, P.

2000-01-01

Long-duration exposure to weightlessness results in bone demineralization, muscle atrophy, cardiovascular deconditioning, altered sensory-motor control, and central nervous system reorganizations. Exercise countermeasures and body loading methods so far employed have failed to prevent these changes. A human mission to Mars might last 2 or 3 years and without effective countermeasures could result in dangerous levels of bone and muscle loss. Artificial gravity generated by rotation of an entire space vehicle or of an inner chamber could be used to prevent structural changes. Some of the physical characteristics of rotating environments are outlined along with their implications for human performance. Artificial gravity is the centripetal force generated in a rotating vehicle and is proportional to the product of the square of angular velocity and the radius of rotation. Thus, for a particular g-level, there is a tradeoff between velocity of rotation and radius. Increased radius is vastly more expensive to achieve than velocity, so it is important to know the highest rotation rates to which humans can adapt. Early studies suggested that 3 rpm might be the upper limit because movement control and orientation were disrupted at higher velocities and motion sickness and chronic fatigue were persistent problems. Recent studies, however, are showing that, if the terminal velocity is achieved over a series of gradual steps and many body movements are made at each dwell velocity, then full adaptation of head, arm, and leg movements is possible. Rotation rates as high as 7.5-10 rpm are likely feasible. An important feature of the new studies is that they provide compelling evidence that equilibrium point theories of movement control are inadequate. The central principles of equilibrium point theories lead to the equifinality prediction, which is violated by movements made in rotating reference frames. Copyright 2000 Wiley-Liss, Inc.

Multi-robot task allocation based on two dimensional artificial fish swarm algorithm

NASA Astrophysics Data System (ADS)

Zheng, Taixiong; Li, Xueqin; Yang, Liangyi

2007-12-01

The problem of task allocation for multiple robots is to allocate more relative-tasks to less relative-robots so as to minimize the processing time of these tasks. In order to get optimal multi-robot task allocation scheme, a twodimensional artificial swarm algorithm based approach is proposed in this paper. In this approach, the normal artificial fish is extended to be two dimension artificial fish. In the two dimension artificial fish, each vector of primary artificial fish is extended to be an m-dimensional vector. Thus, each vector can express a group of tasks. By redefining the distance between artificial fish and the center of artificial fish, the behavior of two dimension fish is designed and the task allocation algorithm based on two dimension artificial swarm algorithm is put forward. At last, the proposed algorithm is applied to the problem of multi-robot task allocation and comparer with GA and SA based algorithm is done. Simulation and compare result shows the proposed algorithm is effective.

Preexercise aminoacidemia and muscle protein synthesis after resistance exercise.

PubMed

Burke, Louise M; Hawley, John A; Ross, Megan L; Moore, Daniel R; Phillips, Stuart M; Slater, Gary R; Stellingwerff, Trent; Tipton, Kevin D; Garnham, Andrew P; Coffey, Vernon G

2012-10-01

We have previously shown that the aminoacidemia caused by the consumption of a rapidly digested protein after resistance exercise enhances muscle protein synthesis (MPS) more than the amino acid (AA) profile associated with a slowly digested protein. Here, we investigated whether differential feeding patterns of a whey protein mixture commencing before exercise affect postexercise intracellular signaling and MPS. Twelve resistance-trained males performed leg resistance exercise 45 min after commencing each of three volume-matched nutrition protocols: placebo (PLAC, artificially sweetened water), BOLUS (25 g of whey protein + 5 g of leucine dissolved in artificially sweetened water; 1 × 500 mL), or PULSE (15 × 33-mL aliquots of BOLUS drink every 15 min). The preexercise rise in plasma AA concentration with PULSE was attenuated compared with BOLUS (P < 0.05); this effect was reversed after exercise, with two-fold greater leucine concentrations in PULSE compared with BOLUS (P < 0.05). One-hour postexercise, phosphorylation of p70 S6K(thr389) and rpS6(ser235/6) was increased above baseline with BOLUS and PULSE, but not PLAC (P < 0.05); furthermore, PULSE > BOLUS (P < 0.05). MPS throughout 5 h of recovery was higher with protein ingestion compared with PLAC (0.037 ± 0.007), with no differences between BOLUS or PULSE (0.085 ± 0.013 vs. 0.095 ± 0.010%.h(-1), respectively, P = 0.56). Manipulation of aminoacidemia before resistance exercise via different patterns of intake of protein altered plasma AA profiles and postexercise intracellular signaling. However, there was no difference in the enhancement of the muscle protein synthetic response after exercise. Protein sources producing a slow AA release, when consumed before resistance exercise in sufficient amounts, are as effective as rapidly digested proteins in promoting postexercise MPS.

Inspiration, simulation and design for smart robot manipulators from the sucker actuation mechanism of cephalopods.

PubMed

Grasso, Frank W; Setlur, Pradeep

2007-12-01

Octopus arms house 200-300 independently controlled suckers that can alternately afford an octopus fine manipulation of small objects and produce high adhesion forces on virtually any non-porous surface. Octopuses use their suckers to grasp, rotate and reposition soft objects (e.g., octopus eggs) without damaging them and to provide strong, reversible adhesion forces to anchor the octopus to hard substrates (e.g., rock) during wave surge. The biological 'design' of the sucker system is understood to be divided anatomically into three functional groups: the infundibulum that produces a surface seal that conforms to arbitrary surface geometry; the acetabulum that generates negative pressures for adhesion; and the extrinsic muscles that allow adhered surfaces to be rotated relative to the arm. The effector underlying these abilities is the muscular hydrostat. Guided by sensory input, the thousands of muscle fibers within the muscular hydrostats of the sucker act in coordination to provide stiffness or force when and where needed. The mechanical malleability of octopus suckers, the interdigitated arrangement of their muscle fibers and the flexible interconnections of its parts make direct studies of their control challenging. We developed a dynamic simulator (ABSAMS) that models the general functioning of muscular hydrostat systems built from assemblies of biologically constrained muscular hydrostat models. We report here on simulation studies of octopus-inspired and artificial suckers implemented in this system. These simulations reproduce aspects of octopus sucker performance and squid tentacle extension. Simulations run with these models using parameters from man-made actuators and materials can serve as tools for designing soft robotic implementations of man-made artificial suckers and soft manipulators.

A design concept of parallel elasticity extracted from biological muscles for engineered actuators.

PubMed

Chen, Jie; Jin, Hongzhe; Iida, Fumiya; Zhao, Jie

2016-08-23

Series elastic actuation that takes inspiration from biological muscle-tendon units has been extensively studied and used to address the challenges (e.g. energy efficiency, robustness) existing in purely stiff robots. However, there also exists another form of passive property in biological actuation, parallel elasticity within muscles themselves, and our knowledge of it is limited: for example, there is still no general design strategy for the elasticity profile. When we look at nature, on the other hand, there seems a universal agreement in biological systems: experimental evidence has suggested that a concave-upward elasticity behaviour is exhibited within the muscles of animals. Seeking to draw possible design clues for elasticity in parallel with actuators, we use a simplified joint model to investigate the mechanisms behind this biologically universal preference of muscles. Actuation of the model is identified from general biological joints and further reduced with a specific focus on muscle elasticity aspects, for the sake of easy implementation. By examining various elasticity scenarios, one without elasticity and three with elasticity of different profiles, we find that parallel elasticity generally exerts contradictory influences on energy efficiency and disturbance rejection, due to the mechanical impedance shift thus caused. The trade-off analysis between them also reveals that concave parallel elasticity is able to achieve a more advantageous balance than linear and convex ones. It is expected that the results could contribute to our further understanding of muscle elasticity and provide a theoretical guideline on how to properly design parallel elasticity behaviours for engineering systems such as artificial actuators and robotic joints.

Exogenous skeletal muscle satellite cells promote the repair of levator palpebrae superioris mechanical damage in rat.

PubMed

Ye, Lin; Yao, Yuanyuan; Guo, Hui; Peng, Yun

2018-05-17

Blepharoptosis is a drooping of the upper eyelid, usually due to dysfunction of the levator palpebrae superioris (LPS). Recently, skeletal muscle satellite cells (SSCs) have been reported to promote the repair of damaged skeletal muscle. This study aims to investigate the potential contribution of exogenous SSCs to the regeneration of mechanically damaged LPS. Thirty-two rats were randomly divided into four groups, including control group, SSCs-treated group, SSCs-treated injury group and non-treated injury group. After rats in injury groups were artificially lacerated on both the left and right LPS, HBBS (Hank's Balanced Salt Solution) containing SSCs was injected into upper eyelid tissue. After 7 days, the LPS muscle tissues were excised. In addition, skeletal muscle cells (SMCs) and SSCs were cocultured for use as an in vitro model, and the protective effects of SSCs on cultured SMCs were also investigated. Histological staining revealed that exogenous SSCs repaired the damaged muscle fibers and attenuated the fibrosis of LPS, possibly due to the increased level of IGF-1. In contrast, the level of IL-1β, IL-6, TGF-β1 and Smad2/3 (phospho-T8) were significantly reduced in the SSCs-treated group. The in vitro model using coculture of skeletal muscle cells (SMCs) and SSCs also revealed an increased level of IGF-1 and reduced level of inflammatory factors, resulting in a better cell survival rate. This study found that exogenous SSCs can promote the repair of LPS mechanical damage and provides new insight into the development of novel therapeutic approaches for blepharoptosis.

Biologically inspired intelligent robots

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph; Breazeal, Cynthia

2003-07-01

Humans throughout history have always sought to mimic the appearance, mobility, functionality, intelligent operation, and thinking process of biological creatures. This field of biologically inspired technology, having the moniker biomimetics, has evolved from making static copies of human and animals in the form of statues to the emergence of robots that operate with realistic behavior. Imagine a person walking towards you where suddenly you notice something weird about him--he is not real but rather he is a robot. Your reaction would probably be "I can't believe it but this robot looks very real" just as you would react to an artificial flower that is a good imitation. You may even proceed and touch the robot to check if your assessment is correct but, as oppose to the flower case, the robot may be programmed to respond physical and verbally. This science fiction scenario could become a reality as the current trend continues in developing biologically inspired technologies. Technology evolution led to such fields as artificial muscles, artificial intelligence, and artificial vision as well as biomimetic capabilities in materials science, mechanics, electronics, computing science, information technology and many others. This paper will review the state of the art and challenges to biologically-inspired technologies and the role that EAP is expected to play as the technology evolves.

Effectiveness of centrifuge-induced artificial gravity with ergometric exercise as a countermeasure during simulated microgravity exposure in humans.

PubMed

Iwase, Satoshi

2005-01-01

To test the effectiveness of centrifuge-induced artificial gravity with ergometric exercise, 12 healthy young men (20.7 +/- 1.9 yr) were exposed to simulated microgravity for 14 days of -6 degrees head-down bedrest. Half the subjects were randomly selected and loaded 1.2 G artificial gravity with 60 W (four out of six subjects) or 40 W (two out of six subjects) of ergometric workload on days 1, 2, 3, 5, 7, 9, 11, 12, 13, 14 (CM group). The rest of the subjects served as the control. Anti-G score, defined as the G-load x running time to the endpoint, was significantly elongated by the load of the centrifuge-ergometer. Plasma volume loss was suppressed (-5.0 +/- 2.4 vs. -16.4 +/- 1.9%), and fluid volume shift was prevented by the countermeasure load. Elevated heart rate and muscle sympathetic nerve activity after bedrest were counteracted, and exaggerated response to head-up tilt was also suppressed. Centrifuge-induced artificial gravity with exercise is effective in preventing cardiovascular deconditioning due to microgravity exposure, however, an effective and appropriate regimen (magnitude of G-load and exercise workload) should be determined in future studies. c2005 Elsevier Ltd. All rights reserved.

Effectiveness of centrifuge-induced artificial gravity with ergometric exercise as a countermeasure during simulated microgravity exposure in humans

NASA Astrophysics Data System (ADS)

Iwase, Satoshi

2005-07-01

To test the effectiveness of centrifuge-induced artificial gravity with ergometric exercise, 12 healthy young men (20.7±1.9yr) were exposed to simulated microgravity for 14 days of -6∘ head-down bedrest. Half the subjects were randomly selected and loaded 1.2 G artificial gravity with 60 W (four out of six subjects) or 40 W (two out of six subjects) of ergometric workload on days 1,2,3,5,7,9,11,12,13,14 (CM group). The rest of the subjects served as the control. Anti-G score, defined as the G-load×running time to the endpoint, was significantly elongated by the load of the centrifuge-ergometer. Plasma volume loss was suppressed ( -5.0±2.4 vs. -16.4±1.9%), and fluid volume shift was prevented by the countermeasure load. Elevated heart rate and muscle sympathetic nerve activity after bedrest were counteracted, and exaggerated response to head-up tilt was also suppressed. Centrifuge-induced artificial gravity with exercise is effective in preventing cardiovascular deconditioning due to microgravity exposure, however, an effective and appropriate regimen (magnitude of G-load and exercise workload) should be determined in future studies.

Generation of an artificial skin construct containing a non-degradable fiber mesh: a potential transcutaneous interface

PubMed Central

Cahn, Frederick; Kyriakides, Themis R

2009-01-01

Generation of a stable interface between soft tissues and biomaterials could improve the function of transcutaneous prostheses, primarily by minimizing chronic infections. We hypothesized that inclusion of non-biodegradable biomaterials in an artificial skin substrate would improve integration of the neodermis. In the present study, we compared the biocompatibility of an experimental substrate, consisting of collagen and glycosylaminoglycans, with commercially available artificial skin of similar composition. By utilizing a mouse excisional wound model, we found that the source of collagen (bovine tendon versus hide), extent of injury and wound contraction were critical determinants of inflammation and neodermis formation. Reducing the extent of injury to underlying muscle reduced inflammation and improved remodeling; the improved conditions allowed the detection of a pro-inflammatory effect of hide-derived collagen. To eliminate the complication of wound contraction, subsequent grafts were performed in guinea pigs and showed that inclusion of carbon fibers or non-degradable sutures resulted in increased foreign body response (FBR) and altered remodeling. On the other hand, inclusion of a polyester multi-stranded mesh induced a mild FBR and allowed normal neodermis formation. Taken together, our observations suggest that non-degradable biomaterials can be embedded in an artificial skin construct without compromising its ability to induce neodermis formation. PMID:18689926

Evaluation of a musculoskeletal model with prosthetic knee through six experimental gait trials.

PubMed

Kia, Mohammad; Stylianou, Antonis P; Guess, Trent M

2014-03-01

Knowledge of the forces acting on musculoskeletal joint tissues during movement benefits tissue engineering, artificial joint replacement, and our understanding of ligament and cartilage injury. Computational models can be used to predict these internal forces, but musculoskeletal models that simultaneously calculate muscle force and the resulting loading on joint structures are rare. This study used publicly available gait, skeletal geometry, and instrumented prosthetic knee loading data [1] to evaluate muscle driven forward dynamics simulations of walking. Inputs to the simulation were measured kinematics and outputs included muscle, ground reaction, ligament, and joint contact forces. A full body musculoskeletal model with subject specific lower extremity geometries was developed in the multibody framework. A compliant contact was defined between the prosthetic femoral component and tibia insert geometries. Ligament structures were modeled with a nonlinear force-strain relationship. The model included 45 muscles on the right lower leg. During forward dynamics simulations a feedback control scheme calculated muscle forces using the error signal between the current muscle lengths and the lengths recorded during inverse kinematics simulations. Predicted tibio-femoral contact force, ground reaction forces, and muscle forces were compared to experimental measurements for six different gait trials using three different gait types (normal, trunk sway, and medial thrust). The mean average deviation (MAD) and root mean square deviation (RMSD) over one gait cycle are reported. The muscle driven forward dynamics simulations were computationally efficient and consistently reproduced the inverse kinematics motion. The forward simulations also predicted total knee contact forces (166N

Fibrin matrix for suspension of regenerative cells in an artificial nerve conduit.

PubMed

Kalbermatten, D F; Kingham, P J; Mahay, D; Mantovani, C; Pettersson, J; Raffoul, W; Balcin, H; Pierer, G; Terenghi, G

2008-06-01

Peripheral nerve injury presents with specific problems of neuronal reconstructions, and from a clinical viewpoint a tissue engineering approach would facilitate the process of repair and regeneration. We have previously used artificial nerve conduits made from bioresorbable poly-3-hydroxybutyrate (PHB) in order to refine the ways in which peripheral nerves are repaired and reconnected to the target muscles and skin. The addition of Schwann cells (SC) or differentiated mesenchymal stem cells (dMSC) to the conduits enhances regeneration. In this study, we have used a matrix based on fibrin (Tisseel) to fill optimally the nerve-conduits with cells. In vitro analysis showed that both SC and MSC adhered significantly better to PHB in the presence of fibrin and cells continued to maintain their differentiated state. Cells were more optimally distributed throughout the conduit when seeded in fibrin than by delivery in growth medium alone. Transplantation of the nerve conduits in vivo showed that cells in combination with fibrin matrix significantly increased nerve regeneration distance (using PGP9.5 and S100 distal and proximal immunohistochemistry) when compared with empty PHB conduits. This study shows the beneficial combinatory effect of an optimised matrix, cells and conduit material as a step towards bridging nerve gaps which should ultimately lead to improved functional recovery following nerve injury.

Multi-scale finite element analyses for stress and strain evaluations of braid fibril artificial blood vessel and smooth muscle cell.

PubMed

Nakamachi, Eiji; Uchida, Takahiro; Kuramae, Hiroyuki; Morita, Yusuke

2014-08-01

In this study, we developed a multi-scale finite element (FE) analysis code to obtain the stress and strain that occurred in the smooth muscle cell (SMC) at micro-scale, which was seeded in the real fabricated braid fibril artificial blood vessel. This FE code can predict the dynamic response of stress under the blood pressure loading. We try to establish a computer-aided engineering (CAE)-driven scaffold design technique for the blood vessel regeneration. Until now, there occurred the great progresses for the endothelial cell activation and intima layer regeneration in the blood vessel regeneration study. However, there remains the difficulty of the SMC activation and media layer regeneration. Therefore, many researchers are now studying to elucidate the fundamental mechanism of SMC activation and media layer regeneration by using the biomechanical technique. As the numerical tool, we used the dynamic-explicit FE code PAM-CRASH, ESI Ltd. For the material models, the nonlinear viscoelastic constitutive law was adapted for the human blood vessel, SMC and the extra-cellular matrix, and the elastic law for the polyglycolic acid (PGA) fiber. Through macro-FE and micro-FE analyses of fabricated braid fibril tubes by using PGA fiber under the combined conditions of the orientation angle and the pitch of fiber, we searched an appropriate structure for the stress stimulation for SMC functionalization. Objectives of this study are indicated as follows: 1. to analyze the stress and strain of the human blood vessel and SMC, and 2. to calculate stress and strain of the real fabricated braid fibril artificial blood vessel and SMC to search an appropriate PGA fiber structure under combined conditions of PGA fiber numbers, 12 and 24, and the helical orientation angles of fiber, 15, 30, 45, 60, and 75 degrees. Finally, we found a braid fibril tube, which has an angle of 15 degree and 12 PGA fibers, as a most appropriate artificial blood vessel for SMC functionalization. Copyright © 2014 John Wiley & Sons, Ltd.

The “Artificial Artery” as In Vitro Perfusion Model

PubMed Central

Rüth, Marieke; Buschmann, Ivo; Lemke, Horst-Dieter; Jacobi, Dorit; Knaus, Petra; Spindler, Ernst; Zidek, Walter; Lehmann, Kerstin; Jankowski, Vera

2013-01-01

Metabolic stimuli, pressure, and fluid shear stress (FSS) are major mediators of vascular plasticity. The exposure of the vessel wall to increased laminar FSS is the main trigger of arteriogenesis, the remodelling of pre-existent arterio-arteriolar anastomoses to functional conductance arteries. In this study, we have used an in vitro bioreactor to investigate cell-specific interactions, molecular mechanisms as well as time-dependent effects under laminar FSS conditions. This bioreactor termed “artificial artery” can be used for screening potential arterio-protective substances, pro-arteriogenic factors, and for investigating biomarkers of cardiovascular diseases such as cardiac diseases. The bioreactor is built up out of 14 hollow fiber membranes colonized with endothelial cells (HUVECs) on the inside and smooth muscle cells (HUASMCs) on the outside. By means of Hoechst 33342 staining as well as immunocytochemistry of ß-catenin and α-smooth-muscle-actin, a microporous polypropylene membrane was characterized as being the appropriate polymer for co-colonization. Defined arterial flow conditions (0.1 N/m2 and 3 N/m2), metabolic exchange, and cross-talk of HUVECs and HUASMCs through hollow fibers mimic physiological in vivo conditions of the vasculature. Analysing mono- and co-culture secretomes by MALDI-TOF-TOF mass spectrometry, we could show that HUVECs secreted Up4A upon 3 N/m2. A constant cellular secretion of randomly chosen peptides verified viability of the “artificial artery” for a cultivation period up to five days. qRT-PCR analyses revealed an up-regulation of KLF2 and TIMP1 as mechano-regulated genes and demonstrated arterio-protective, homeostatic FSS conditions by a down-regulation of EDN1. Expression analyses of VWF and EDN1 furthermore confirmed that RNA of both cell types could separately be isolated without cross-contamination. CCND1 mRNA expression in HUVECs did not change upon FSS indicating a quiescent endothelial phenotype. Taken together, the “artificial artery” provides a solid in vitro model to test pharmacological active compounds for their impact on arterio-damaging or arterio-protective properties on vascular response. PMID:23505419

Electromechanically active polymer transducers: research in Europe

NASA Astrophysics Data System (ADS)

Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

2013-10-01

Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial Muscles—ESNAM', entirely focused on EAPs and gathering the most active research institutes, as well as key industrial developers and end users. The ESNAM network has received financial support from the European COST (Cooperation in Science and Technology) programme (COST Action MP1003), leading to fruitful collaboration, of which some results are showcased in this issue. This focus issue deals with a number of relevant topics on ionic and electronic EAPs. The contents, which span highly heterogeneous and cross diverse disciplines, such as physics, chemistry, material science and engineering, embrace size scales from nano to macro, and cover different areas, such as new materials, devices and applications. This collection of papers helps elucidate, on the one hand, how heterogeneous and dynamic the EAP field is in general and, on the other hand, the state of the art of the EAP research in Europe. We hope that this focus issue might help to stimulate future work in this emerging field of research and generate new applications. Acknowledgments We would like to thank all the authors for their contributions, and the Smart Materials and Structures Editor-in-Chief, Professor Garcia, for having accepted our proposal to organize this focus issue. Special thanks also go to Natasha Leeper, from the IOP Publishing team, for her continued support and impeccable professionalism in arranging this focus issue. We also gratefully acknowledge financial support from COST (European Cooperation in Science and Technology) in the framework of 'ESNAM—European Scientific Network for Artificial Muscles' (COST Action MP1003), which made possible cooperation that led to contributions to this issue.

The incorporation of hydrophobic protein receptors and artificial lipid membranes.

PubMed

Reader, T A; Fiszer de Plazas, S; Salas, P J; de Robertis, E

1976-01-01

The mechanism of chemical synaptic transmission implies: 1) the existence of a specific protein receptor at the postsynaptic membrane, and 2) the interaction between the transmitter released and the receptor, thus producing a change in ionic permeability. Previous studies from our laboratory have shown that special hydrophobic proteins extracted from postsynpatic membranes of different tissues showed a high affinity binding for the different pharmacological agents. The present paper describes experiments in which different hydrophobic protein binding acetylcholine, noradrenaline, gamma-aminobutyric acid, and glutamate were incorporated into artificial lipid membranes, similar to those first described by Mueller et al. (19). The effect of the different pharmacological agents was tested under experimental conditions of voltage clamp and the d.c. current changes measured. The results were then compared for the different lipid-protein membranes employed during the steady state and during transient conductance changes. The specificity of the responses indicate that artificial lipid membranes containing these hydrophobic proteins from electroplax, myocardium, spleen capsule and shrimp muscle can be used as a model to study pharmacologic receptors.

Energy profiling of demersal fish: a case-study in wind farm artificial reefs.

PubMed

De Troch, Marleen; Reubens, Jan T; Heirman, Elke; Degraer, Steven; Vincx, Magda

2013-12-01

The construction of wind farms introduces artificial hard substrates in sandy sediments. As Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus) tend to aggregate in order to feed around these reefs, energy profiling and trophic markers were applied to study their feeding ecology in a wind farm in the Belgian part of the North Sea. The proximate composition (carbohydrates, proteins and lipids) differed significantly between liver and muscle tissue but not between fish species or between their potential prey species. Atlantic cod showed to consume more energy than pouting. The latter had a higher overall energy reserve and can theoretically survive twice as long on the available energy than cod. In autumn, both fish species could survive longer on their energy than in spring. Polyunsaturated fatty acids were found in high concentrations in fish liver. The prey species Jassa and Pisidia were both rich in EPA while Jassa had a higher DHA content than Pisidia. Energy profiling supported the statement that wind farm artificial reefs are suitable feeding ground for both fish species. Sufficient energy levels were recorded and there is no indication of competition.

MMP-14 is necessary but not sufficient for invasion of three-dimensional collagen by human muscle satellite cells

PubMed Central

Lund, Dane K.; Mouly, Vincent

2014-01-01

The twenty-five known matrix metalloproteases (MMPs) and their endogenous inhibitors, tissue inhibitors of metalloproteases (TIMPs), mediate cell invasion through the extracellular matrix (ECM). In a comparative three-dimensional assay, we analyzed human and mouse satellite cells' competence to invade an artificial ECM (collagen I). We identified a single MMP that 1) is expressed by human muscle satellite cells; 2) is induced at the mRNA/protein level by adhesion to collagen I; and 3) is necessary for invasion into a collagen I matrix. Interestingly, murine satellite cells neither express this MMP, nor invade the collagen matrix. However, exogenous human MMP-14 is not sufficient to induce invasion of a collagen matrix by murine cells, emphasizing species differences. PMID:24898588

Towards seamlessly-integrated textile electronics: methods to coat fabrics and fibers with conducting polymers for electronic applications.

PubMed

Allison, Linden; Hoxie, Steven; Andrew, Trisha L

2017-06-29

Traditional textile materials can be transformed into functional electronic components upon being dyed or coated with films of intrinsically conducting polymers, such as poly(aniline), poly(pyrrole) and poly(3,4-ethylenedioxythiophene). A variety of textile electronic devices are built from the conductive fibers and fabrics thus obtained, including: physiochemical sensors, thermoelectric fibers/fabrics, heated garments, artificial muscles and textile supercapacitors. In all these cases, electrical performance and device ruggedness is determined by the morphology of the conducting polymer active layer on the fiber or fabric substrate. Tremendous variation in active layer morphology can be observed with different coating or dyeing conditions. Here, we summarize various methods used to create fiber- and fabric-based devices and highlight the influence of the coating method on active layer morphology and device stability.

Dual-responsive soft actuators based on self-assembled polymers

NASA Astrophysics Data System (ADS)

Kim, Seung Jae; Park, Moon Jeong

Electroactive polymer actuators (EAPs) have been extensively studied for biomimetic technologies such as artificial muscles and soft robotics. While a large deformation can be achievable from EAPs under relatively low-driving voltages, the slow response time has long been a fundamental drawback of EAPs. Here, we investigate a new soft actuator capable of responding two different external stimuli. The actuator is composed of electroactive polymer and light-responsive polymer. We have employed ionic block copolymers having well-connected ion-conduction channels to raise response to electric-field. Light-responsive polymers were additionally incorporated into them to control the deformation of the actuator in an independent manner. Noteworthy observation in the present study is that the dual-responsive polymers resulted in synergetic achievement of high bending strain and fast response time, which marked a significant improvement from the conventional EAPs.

Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays

PubMed Central

Lu, S. G.; Chen, X.; Levard, T.; Diglio, P. J.; Gorny, L. J.; Rahn, C. D.; Zhang, Q. M.

2015-01-01

Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly. PMID:26079628

Effect of Increased Cyclic AMP Concentration on Muscle Protein Synthesis and Beta-Adrenergic Receptor Expression in Chicken Skeletal Muscle Cells in Culture

NASA Technical Reports Server (NTRS)

Young, R. B.; Vaughn, J. R.; Bridge, K. Y.; Smith, C. K.

1998-01-01

Analogies of epinephrine are known to cause hypertrophy of skeletal muscle when fed to animals. These compounds presumably exert their physiological action through interaction with the P-adrenergic receptor. Since the intracellular signal generated by the Beta-adrenergic receptor is cyclic AMP (cAMP), experiments were initiated in cell culture to determine if artificial elevation of cAMP by treatment with forskolin would alter muscle protein metabolism and P-adrenergic receptor expression. Chicken skeletal muscle cells after 7 days in culture were treated with 0.2-30 micrometers forskolin for a total of three days. At the end of the treatment period, both the concentration of cAMP and the quantity of myosin heavy chain (MHC) were measured. Concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. In contrast, the quantity of MHC was increased approximately 50% above control cells at 0.2 micrometers forskolin, but exhibited a gradual decline at higher levels of forskolin so that the quantity of MHC in cells treated with 30 micrometers forskolin was not significantly different from controls. Curiously, the intracellular concentration of cAMP which elicited the maximum increase in the quantity of MHC was only 40% higher than cAMP concentration in control cells.

Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults With Amputations

NASA Technical Reports Server (NTRS)

Atkins, Diane J.

1998-01-01

The first single function myoelectric prosthetic hand was introduced in the 1960's. This hand was controlled by the electric fields generated by muscle contractions in the residual limb of the amputee user. Electrodes and amplifiers, embedded in the prosthetic socket, measured these electric fields across the skin, which increase in amplitude as the individual contracts their muscle. When the myoelectric signal reached a certain threshold amplitude, the control unit activated a motor which opened or closed a hand-like prosthetic terminal device with a pincher grip. Late in the 1990's, little has changed. Most current myoelectric prostheses still operate in this same, single-function way. To better understand the limitations of the current single-function myoelectric hand and the needs of those who use them, The Institute for Rehabilitation and Research (TIRR), sponsored by the National Institutes of Health (NUH), surveyed approximately 2,500 individuals with upper limb loss [1]. When asked to identify specific features of their current myoelectric prostheses that needed improvement, the survey respondents overwhelmingly identified the lack of wrist and finger movement, as well as poor control capability. However, simply building a mechanism with individual finger and wrist motion is not enough. In the 1960's and 1970's, engineers built a number of more dexterous prosthetic hands. Unfortunately, these were rejected during clinical trials due to a difficult and distracting control interface. The goal of this project, "Applying Space Technology to Enhance Control of an Artificial Arm for Children and Adults with Amputations," was to lay the foundation for a multi-function, intuitive myoelectric control system which requires no conscious thought to move the hand. We built an extensive myoelectric signal database for six motions from ten amputee volunteers, We also tested a control system based on new artificial intelligence techniques on the data from two of these subjects. This data is available to anyone doing myoelectric control research. Its availability is an important contribution to the prosthetics research community, as many researchers do not have access to amputee subjects. Since we collected myoelectric data from subjects' sound arms as well as their residual arms, this database will also prove useful to virtual reality and robotics researchers who want to explore myoelectric-based interfaces between any user and a machine. Currently, one small company (Intelligenta, Inc.) and one university (University of New Brunswick, Canada) are using this myoelectric database under other funding to develop multifunction control systems for prostheses. A prosthetics manufacturer (Liberty Technology, Inc.) is making plans to incorporate the results of their work into an artificial hand capable of several different movements to provide functionality only dreamed of by current myoelectric users. Methods Six adults and four children, all with unilateral, below-elbow amputations served as subjects. Five of the adults (3 male, 2 female, average age 34 years) had amputations due to traumatic injury, while one adult (female, age 32 years) and the four children (3 male, 1 female, average age 13 years) had congenital (i.e. from birth) limb deficiencies.

Experimental characterization of thermally-activated artificial muscles based on coiled nylon fishing lines

NASA Astrophysics Data System (ADS)

Cherubini, Antonello; Moretti, Giacomo; Vertechy, Rocco; Fontana, Marco

2015-06-01

The discovery of an innovative class of thermally activated actuators based on twisted polymeric fibres has opened new horizons toward the development of effective devices that can be easily manufactured using inexpensive materials such as fishing lines or sewing threads. These new devices show large deformations when heated together with promising performance in terms of energy and power densities. With the aim of providing information and data useful for the future engineering applications, we present the results of a thermo-mechanical characterization conducted on a specific type of twisted polymeric fibre (i.e. nylon-made coiled actuators) that is considered particularly promising. A custom experimental test-bench and procedure have been developed and employed to run isothermal and isometric tensile tests on a set of specimens that are fabricated with a simple and repeatable process. The results of the experiments highlight some important issues related to the response of these actuators such as hysteresis, repeatability, predictability and stored elastic energy.

High-performance graphdiyne-based electrochemical actuators.

PubMed

Lu, Chao; Yang, Ying; Wang, Jian; Fu, Ruoping; Zhao, Xinxin; Zhao, Lei; Ming, Yue; Hu, Ying; Lin, Hongzhen; Tao, Xiaoming; Li, Yuliang; Chen, Wei

2018-02-21

Electrochemical actuators directly converting electrical energy to mechanical energy are critically important for artificial intelligence. However, their energy transduction efficiency is always lower than 1.0% because electrode materials lack active units in microstructure, and their assembly systems can hardly express the intrinsic properties. Here, we report a molecular-scale active graphdiyne-based electrochemical actuator with a high electro-mechanical transduction efficiency of up to 6.03%, exceeding that of the best-known piezoelectric ceramic, shape memory alloy and electroactive polymer reported before, and its energy density (11.5 kJ m -3 ) is comparable to that of mammalian skeletal muscle (~8 kJ m -3 ). Meanwhile, the actuator remains responsive at frequencies from 0.1 to 30 Hz with excellent cycling stability over 100,000 cycles. Furthermore, we verify the alkene-alkyne complex transition effect responsible for the high performance through in situ sum frequency generation spectroscopy. This discovery sheds light on our understanding of actuation mechanisms and will accelerate development of smart actuators.

Graphitic carbon nitride nanosheet electrode-based high-performance ionic actuator

PubMed Central

Wu, Guan; Hu, Ying; Liu, Yang; Zhao, Jingjing; Chen, Xueli; Whoehling, Vincent; Plesse, Cédric; Nguyen, Giao T. M.; Vidal, Frédéric; Chen, Wei

2015-01-01

Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation. Because actuation performance is mainly dominated by the electrochemical and electromechanical processes of the electrode layer, the electrode material and structure are crucial. Here, we report a graphitic carbon nitride nanosheet electrode-based ionic actuator that displays high electrochemical activity and electromechanical conversion abilities, including large specific capacitance (259.4 F g−1) with ionic liquid as the electrolyte, fast actuation response (0.5±0.03% in 300 ms), large electromechanical strain (0.93±0.03%) and high actuation stability (100,000 cycles) under 3 V. The key to the high performance lies in the hierarchical pore structure with dominant size <2 nm, optimal pyridinic nitrogen active sites (6.78%) and effective conductivity (382 S m−1) of the electrode. Our study represents an important step towards artificial muscle technology in which heteroatom modulation in electrodes plays an important role in promoting electrochemical actuation performance. PMID:26028354

Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocomposites

NASA Astrophysics Data System (ADS)

Wan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, Qunfeng

2016-03-01

Inspired by the relationship between interface interactions and the high performance mechanical properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepared via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, respectively. In addition, the effect of environmental relative humidity on the mechanical properties of bioinspired nanocomposites is also investigated, and is consistent with previous theoretical predictions. Moreover, this nacre-inspired nanocomposite also displays high electrical conductivity of 108.9 S cm-1. These excellent physical properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.

Algorithms for optimization of the transport system in living and artificial cells.

PubMed

Melkikh, A V; Sutormina, M I

2011-06-01

An optimization of the transport system in a cell has been considered from the viewpoint of the operations research. Algorithms for an optimization of the transport system of a cell in terms of both the efficiency and a weak sensitivity of a cell to environmental changes have been proposed. The switching of various systems of transport is considered as the mechanism of weak sensitivity of a cell to changes in environment. The use of the algorithms for an optimization of a cardiac cell has been considered by way of example. We received theoretically for a cell of a cardiac muscle that at the increase of potassium concentration in the environment switching of transport systems for this ion takes place. This conclusion qualitatively coincides with experiments. The problem of synthesizing an optimal system in an artificial cell has been stated.

Design, development and testing of a low-cost sEMG system and its use in recording muscle activity in human gait.

PubMed

Supuk, Tamara Grujic; Skelin, Ana Kuzmanic; Cic, Maja

2014-05-07

Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet-based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics.

A practical multilayered conducting polymer actuator with scalable work output

NASA Astrophysics Data System (ADS)

Ikushima, Kimiya; John, Stephen; Yokoyama, Kazuo; Nagamitsu, Sachio

2009-09-01

Household assistance robots are expected to become more prominent in the future and will require inherently safe design. Conducting polymer-based artificial muscle actuators are one potential option for achieving this safety, as they are flexible, lightweight and can be driven using low input voltages, unlike electromagnetic motors; however, practical implementation also requires a scalable structure and stability in air. In this paper we propose and practically implement a multilayer conducting polymer actuator which could achieve these targets using polypyrrole film and ionic liquid-soaked separators. The practical work density of a nine-layer multilayer actuator was 1.4 kJ m-3 at 0.5 Hz, when the volumes of the electrolyte and counter electrodes were included, which approaches the performance of mammalian muscle. To achieve air stability, we analyzed the effect of air-stable ionic liquid gels on actuator displacement using finite element simulation and it was found that the majority of strain could be retained when the elastic modulus of the gel was kept below 3 kPa. As a result of this work, we have shown that multilayered conducting polymer actuators are a feasible idea for household robotics, as they provide a substantial practical work density in a compact structure and can be easily scaled as required.

Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

PubMed Central

Supuk, Tamara Grujic; Skelin, Ana Kuzmanic; Cic, Maja

2014-01-01

Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics. PMID:24811078

A smooth muscle tone-dependent stretch-activated migrating motor pattern in isolated guinea-pig distal colon.

PubMed

Smith, Terence K; Oliver, Gavin R; Hennig, Grant W; O'Shea, Deirdre M; Vanden Berghe, Pieter; Kang, Sok Han; Spencer, Nick J

2003-09-15

We have investigated the tone dependence of the intrinsic nervous activity generated by localized wall distension in isolated segments of guinea-pig distal colon using mechanical recordings and video imaging of wall movements. A segment of colon was threaded through two partitions, which divided the colon for pharmacological purposes into oral, stimulation and anal regions. An intraluminal balloon was located in the stimulation region between the two partitions (12 mm apart). Maintained colonic distension by an intraluminal balloon or an artificial faecal pellet held at a fixed location generated rhythmic (frequency 0.3 contractions min(-1); duration approximately 60 s) peristaltic waves of contraction. Video imaging of colonic wall movements or the selective application of pharmacological agents suggested that peristaltic waves originated just oral (< or = 4 mm) to the pellet and propagated both orally (approximately 11 mm s(-1)) and anally (approximately 1 mm s(-1)). Also, during a peristaltic wave the colon appears to passively shorten in front of a pellet, as a result of an active contraction of the longitudinal muscle oral to the pellet. Faecal pellet movement only occurred when a rhythmic peristaltic wave was generated. Rhythmic peristaltic waves were abolished in all regions by the smooth muscle relaxants isoproterenol (1 microM), nicardipine (1 microM) or papavarine (10 microM), and by the neural antagonists tetrodotoxin (TTX; 0.6 microM), hexamethonium (100 microM) or atropine (1 microM), when added selectively to the stimulation region. Nicardipine, atropine, TTX, or hexamethonium (100 microM) also blocked the evoked peristaltic waves when selectively added to the oral region. Nomega-nitro-L-arginine (L-NA; 100 microM) added to the anal region reduced the anal relaxation but increased the anal contraction, leading to an increase in the apparent conduction velocity of each peristaltic wave. In conclusion, maintained distension by a fixed artificial pellet generates propulsive, rhythmic peristaltic waves, whose enteric neural activity is critically dependent upon smooth muscle tone. These peristaltic waves usually originate just oral to the pellet, and their apparent conduction velocity is generated by activation of descending inhibitory nerve pathways.

Preoperative overnight parenteral nutrition (TPN) improves skeletal muscle protein metabolism indicated by microarray algorithm analyses in a randomized trial.

PubMed

Iresjö, Britt-Marie; Engström, Cecilia; Lundholm, Kent

2016-06-01

Loss of muscle mass is associated with increased risk of morbidity and mortality in hospitalized patients. Uncertainties of treatment efficiency by short-term artificial nutrition remain, specifically improvement of protein balance in skeletal muscles. In this study, algorithmic microarray analysis was applied to map cellular changes related to muscle protein metabolism in human skeletal muscle tissue during provision of overnight preoperative total parenteral nutrition (TPN). Twenty-two patients (11/group) scheduled for upper GI surgery due to malignant or benign disease received a continuous peripheral all-in-one TPN infusion (30 kcal/kg/day, 0.16 gN/kg/day) or saline infusion for 12 h prior operation. Biopsies from the rectus abdominis muscle were taken at the start of operation for isolation of muscle RNA RNA expression microarray analyses were performed with Agilent Sureprint G3, 8 × 60K arrays using one-color labeling. 447 mRNAs were differently expressed between study and control patients (P < 0.1). mRNAs related to ribosomal biogenesis, mRNA processing, and translation were upregulated during overnight nutrition; particularly anabolic signaling S6K1 (P < 0.01-0.1). Transcripts of genes associated with lysosomal degradation showed consistently lower expression during TPN while mRNAs for ubiquitin-mediated degradation of proteins as well as transcripts related to intracellular signaling pathways, PI3 kinase/MAPkinase, were either increased or decreased. In conclusion, muscle mRNA alterations during overnight standard TPN infusions at constant rate altered mRNAs associated with mTOR signaling; increased initiation of protein translation; and suppressed autophagy/lysosomal degradation of proteins. This indicates that overnight preoperative parenteral nutrition is effective to promote muscle protein metabolism. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Artificial grasping system for the paralyzed hand.

PubMed

Ferrari de Castro, M C; Cliquet, A

2000-03-01

Neuromuscular electrical stimulation has been used in upper limb rehabilitation towards restoring motor hand function. In this work, an 8 channel microcomputer controlled stimulator with monophasic square voltage output was used. Muscle activation sequences were defined to perform palmar and lateral prehension and power grip (index finger extension type). The sequences used allowed subjects to demonstrate their ability to hold and release objects that are encountered in daily living, permitting activities such as drinking, eating, writing, and typing.

Environmentally Powered Yarn Arrays that Sense, Actuate, Harvest, and Store Energy (NBIT III)

DTIC Science & Technology

2016-11-15

than the gravimetric power generation capability of a cars combustion engine and (2) functioned as a torsional artificial muscle to rotate a heavy...rotor to over 90,000 rpm. By driving this torsional actuation using 19.6C fluctuations in air temperature, we obtained an average output electrical ...rpm. By driving this torsional actuation using 19.6°C fluctuations in air temperature, we obtained an average output electrical power of 124 W per

Tensile Properties of a Cellulose Ether Hydrogel

NASA Technical Reports Server (NTRS)

Hinkley, Jeffrey A.; Gehrke, Stevin H.

2003-01-01

Poly(hydroxycellulose) solutions were molded into dumbell-shaped specimens crosslinked with divinyl sulfone. The resulting hydrogels were tested in tension at room temperature and also at a temperature above the 40 C shrinkage transition. In contrast to behavior seen in some other responsive gels, apparent initial tangent moduli were lower in the shrunken state; breaking elongations were significantly higher. Possible molecular mechanisms are suggested, and implications for the design of temperature-responsive actuators ("artificial muscles") from this material are discussed.

Design of anisotropic pneumatic artificial muscles and their applications to soft wearable devices for text neck symptoms.

PubMed

Hojoong Kim; Hyuntai Park; Jongwoo Kim; Kyu-Jin Cho; Yong-Lae Park

2017-07-01

Pneumatic artificial muscles (PAMs) are frequently used actuators in soft robotics due to their structural flexibility. They are generally characterized by the tensile force due to the axial contraction and the radial force with volume expansion. To date, most applications of P AMs have utilized axial contractions. In contrast, we propose a novel way to control radial expansions of particular P AMs using anisotropic behaviors. P AMs generally consist of a cylindrical rubber bladder that expands with injection of air and multiple flexible but inextensible strings or mesh that surround the bladder to generate axial contraction force. We propose methods of generating radial expansion force in two ways. One is to control the spatial density of the strings that hold the bladder, and the other is to give asymmetric patterns directly to the bladder for geometrical anisotropy. To evaluate the performance of the actuators, soft sensors made of a hyperelastic material and a liquid conductor were attached to the P AMs for measuring local strains and pressures of the PAMs. We also suggest use of the proposed PAMs to a wearable therapeutic device for treating text neck symptoms as an application. The P AMs were used to exert a pressure to the back of the neck to recover the original spinal alignment from the deformed shape.

Design of a Lightweight Soft Robotic Arm Using Pneumatic Artificial Muscles and Inflatable Sleeves.

PubMed

Ohta, Preston; Valle, Luis; King, Jonathan; Low, Kevin; Yi, Jaehyun; Atkeson, Christopher G; Park, Yong-Lae

2018-04-01

As robots begin to interact with humans and operate in human environments, safety becomes a major concern. Conventional robots, although reliable and consistent, can cause injury to anyone within its range of motion. Soft robotics, wherein systems are made to be soft and mechanically compliant, are thus a promising alternative due to their lightweight nature and ability to cushion impacts, but current designs often sacrifice accuracy and usefulness for safety. We, therefore, have developed a bioinspired robotic arm combining elements of rigid and soft robotics such that it exhibits the positive qualities of both, namely compliance and accuracy, while maintaining a low weight. This article describes the design of a robotic arm-wrist-hand system with seven degrees of freedom (DOFs). The shoulder and elbow each has two DOFs for two perpendicular rotational motions on each joint, and the hand has two DOFs for wrist rotations and one DOF for a grasp motion. The arm is pneumatically powered using custom-built McKibben type pneumatic artificial muscles, which are inflated and deflated using binary and proportional valves. The wrist and hand motions are actuated through servomotors. In addition to the actuators, the arm is equipped with a potentiometer in each joint for detecting joint angle changes. Simulation and experimental results for closed-loop position control are also presented in the article.

Soft shape-adaptive gripping device made from artificial muscle

NASA Astrophysics Data System (ADS)

Hamburg, E.; Vunder, V.; Johanson, U.; Kaasik, F.; Aabloo, A.

2016-04-01

We report on a multifunctional four-finger gripper for soft robotics, suitable for performing delicate manipulation tasks. The gripping device is comprised of separately driven gripping and lifting mechanisms, both made from a separate single piece of smart material - ionic capacitive laminate (ICL) also known as artificial muscle. Compared to other similar devices the relatively high force output of the ICL material allows one to construct a device able to grab and lift objects exceeding multiple times its own weight. Due to flexible design of ICL grips, the device is able to adapt the complex shapes of different objects and allows grasping single or multiple objects simultaneously without damage. The performance of the gripper is evaluated in two different configurations: a) the ultimate grasping strength of the gripping hand; and b) the maximum lifting force of the lifting actuator. The ICL is composed of three main layers: a porous membrane consisting of non-ionic polymer poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITFS), and a reinforcing layer of woven fiberglass cloth. Both sides of the membrane are coated with a carbonaceous electrode. The electrodes are additionally covered with thin gold layers, serving as current collectors. Device made of this material operates silently, requires low driving voltage (<3 V), and is suitable for performing tasks in open air environment.

Biohybrid Control of General Linear Systems Using the Adaptive Filter Model of Cerebellum.

PubMed

Wilson, Emma D; Assaf, Tareq; Pearson, Martin J; Rossiter, Jonathan M; Dean, Paul; Anderson, Sean R; Porrill, John

2015-01-01

The adaptive filter model of the cerebellar microcircuit has been successfully applied to biological motor control problems, such as the vestibulo-ocular reflex (VOR), and to sensory processing problems, such as the adaptive cancelation of reafferent noise. It has also been successfully applied to problems in robotics, such as adaptive camera stabilization and sensor noise cancelation. In previous applications to inverse control problems, the algorithm was applied to the velocity control of a plant dominated by viscous and elastic elements. Naive application of the adaptive filter model to the displacement (as opposed to velocity) control of this plant results in unstable learning and control. To be more generally useful in engineering problems, it is essential to remove this restriction to enable the stable control of plants of any order. We address this problem here by developing a biohybrid model reference adaptive control (MRAC) scheme, which stabilizes the control algorithm for strictly proper plants. We evaluate the performance of this novel cerebellar-inspired algorithm with MRAC scheme in the experimental control of a dielectric electroactive polymer, a class of artificial muscle. The results show that the augmented cerebellar algorithm is able to accurately control the displacement response of the artificial muscle. The proposed solution not only greatly extends the practical applicability of the cerebellar-inspired algorithm, but may also shed light on cerebellar involvement in a wider range of biological control tasks.

[Counteracting effects of intermittent head-up tilt on simulated-weightlessness induced atrophy of anti-gravity muscles].

PubMed

Liu, C; Zhang, L F; Zhang, L N; Ni, H Y; Zhang, Y Q; Sun, L

2000-12-01

Objective. To study the efficacy of intermittent + Gz (45 degrees head-up tilt, HUT) exposures in preventing or alleviating atrophic changes in hind limb muscles induced by simulated weightlessness. Method. Male Sprague-Dawley (SD) rats were assigned randomly to one of three groups: simultaneous control (CON), simulated weightlessness (SUS), and SUS plus 6 h/d HUT (SUS + HUT). Muscles examined included soleus (SOL), medial gastrocnemius (correction from grastrocnemius) (MG), lateral gastrocnemius (LG) and extensor digitorum longus (EDL). Sections were treated with an adenosinetriphosphatase (ATPase) stain or alkaline phosphatase stain. The cross-sectional areas (CSA) of fibers, the relative proportion of type I fiber and the ratio of capillaries/fibers (C/F) were measured using Leica image analysis system. Result. Compared with CON, the wet weight of hind limb muscles in SUS were significantly reduced. The changes of wet weight in different groups were various. The C/F ratios of all muscles were significantly reduced. SUS + HUT rats showed significant increases in SOL and MG wet weight, and the relative counter-effects of intermittent HUT were 93.4% and 34.8%, respectively. In SUS + HUT group, the CSA of both type I and II fibers and relative proportion of type I fibers were completely recovered in SOL, and partially recovered in MG, while the counter-effects were much less obvious in the fibers of LG and EDL. However, HUT resulted in a significant recovery of the C/F ratios in all muscles. Conclusion. The present study demonstrated that intermittent HUT is effective in counteracting the atrophy induced by simulated weightlessness. The result that reactivity to HUT varied among different muscles suggests that the intermittent artificial gravity should be complemented with other countermeasures.

Leanness and heightened nonresting energy expenditure: role of skeletal muscle activity thermogenesis

PubMed Central

Mukherjee, Sromona; Shukla, Charu; Britton, Steven L.; Koch, Lauren G.; Shi, Haifei; Novak, Colleen M.

2014-01-01

A high-calorie diet accompanied by low levels of physical activity (PA) accounts for the widespread prevalence of obesity today, and yet some people remain lean even in this obesogenic environment. Here, we investigate the cause for this exception. A key trait that predicts high PA in both humans and laboratory rodents is intrinsic aerobic capacity. Rats artificially selected as high-capacity runners (HCR) are lean and consistently more physically active than their low-capacity runner (LCR) counterparts; this applies to both males and females. Here, we demonstrate that HCR show heightened total energy expenditure (TEE) and hypothesize that this is due to higher nonresting energy expenditure (NREE; includes activity EE). After matching for body weight and lean mass, female HCR consistently had heightened nonresting EE, but not resting EE, compared with female LCR. Because of the dominant role of skeletal muscle in nonresting EE, we examined muscle energy use. We found that lean female HCR had higher muscle heat dissipation during activity, explaining their low economy of activity and high activity EE. This may be due to the amplified skeletal muscle expression levels of proteins involved in EE and reduced expression levels of proteins involved in energy conservation in HCR relative to LCR. This is also associated with an increased sympathetic drive to skeletal muscle in HCR compared with LCR. We find little support for the hypothesis that resting metabolic rate is correlated with maximal aerobic capacity if body size and composition are fully considered; rather, the critical factor appears to be activity thermogenesis. PMID:24398400

Activation Pattern of Lower Leg Muscles in Running on Asphalt, Gravel and Grass.

PubMed

Dolenec, Aleš; Štirn, Igor; Strojnik, Vojko

2015-07-01

Running is performed on different natural surfaces (outdoor) and artificial surfaces (indoor). Different surface characteristics cause modification of the lower leg muscle activation pattern to adopt ankle stiffness to these characteristics. So the purpose of our investigation was to study changes of lower leg muscles activation pattern in running on different natural running surfaces. Six male and two female runners participated. The participants ran at a freely chosen velocity in trials on asphalt while in trials on gravel, and grass surfaces they were attempting to reach similar velocities as in the trials on asphalt. Muscle activation of the peroneus brevis, tibialis anterior, soleus, and gastrocnemius medialis of the right leg was recorded. Running on asphalt increased average EMG amplitude of the m. tibialis anterior in the pre-activation phase and the m. gastrocnemius medialis in the entire contact phase compared to running on grass from 0.222 ± 0.113 V to 0.276 ± 0.136 V and from 0.214 ± 0.084 V to 0.238 ± 0.088 V, respectively. The average EMG of m. peroneus brevis in pre-activation phase increased from 0.156 ± 0.026 V to 0.184 ± 0.455 V in running on grass in comparison to running on gravel. Running on different surfaces is connected with different activation patterns of lower leg muscles. Running on asphalt requires stiff ankle joints, running on gravel requires greater stability in ankle joints, while running on grass is the least demanding on lower leg muscles.

Development of countermeasures for medical problems encountered in space flight.

PubMed

Nicogossian, A E; Rummel, J D; Leveton, L; Teeter, R

1992-01-01

By the turn of this century, long-duration space missions, either in low Earth orbit or for got early planetary missions, will become commonplace. From the physiological standpoint, exposure to the weightless environment results in changes in body function, some of which are adaptive in nature and some of which can be life threatening. Important issues such as environmental health, radiation protection, physical deconditioning, and bone and muscle loss are of concern to life scientists and mission designers. Physical conditioning techniques such as exercise are not sufficient to protect future space travellers. A review of past experience with piloted missions has shown that gradual breakdown in bone and muscle tissue, together with fluid losses, despite a vigorous exercise regimen can ultimately lead to increased evidence of renal stones, musculoskeletal injuries, and bone fractures. Biological effects of radiation can, over long periods of time increase the risk of cancer development. Today, a vigorous program of study on the means to provide a complex exercise regimen to the antigravity muscles and skeleton is under study. Additional evaluation of artificial gravity as a mechanism to counteract bone and muscle deconditioning and cardiovascular asthenia is under study. New radiation methods are being developed. This paper will deal with the results of these studies.

Hybrid gait training with an overground robot for people with incomplete spinal cord injury: a pilot study.

PubMed

Del-Ama, Antonio J; Gil-Agudo, Angel; Pons, José L; Moreno, Juan C

2014-01-01

Locomotor training has proved to provide beneficial effect in terms of mobility in incomplete paraplegic patients. Neuroprosthetic technology can contribute to increase the efficacy of a training paradigm in the promotion of a locomotor pattern. Robotic exoskeletons can be used to manage the unavoidable loss of performance of artificially driven muscles. Hybrid exoskeletons blend complementary robotic and neuro-prosthetic technologies. The aim of this pilot study was to determine the effects of hybrid gait training in three case studies with persons with incomplete spinal cord injury (iSCI) in terms of locomotion performance during assisted gait, patient-robot adaptations, impact on ambulation and assessment of lower limb muscle strength and spasticity. Participants with iSCI received interventions with a hybrid bilateral exoskeleton for 4 days. Assessment of gait function revealed that patients improved the 6 min and 10 m walking tests after the intervention, and further improvements were observed 1 week after the intervention. Muscle examination revealed improvements in knee and hip sagittal muscle balance scores and decreased score in ankle extensor balance. It is concluded that improvements in biomechanical function of the knee joint after the tested overground hybrid gait trainer are coherent with improvements in gait performance.

Hybrid gait training with an overground robot for people with incomplete spinal cord injury: a pilot study

PubMed Central

del-Ama, Antonio J.; Gil-Agudo, Ángel; Pons, José L.; Moreno, Juan C.

2014-01-01

Locomotor training has proved to provide beneficial effect in terms of mobility in incomplete paraplegic patients. Neuroprosthetic technology can contribute to increase the efficacy of a training paradigm in the promotion of a locomotor pattern. Robotic exoskeletons can be used to manage the unavoidable loss of performance of artificially driven muscles. Hybrid exoskeletons blend complementary robotic and neuro-prosthetic technologies. The aim of this pilot study was to determine the effects of hybrid gait training in three case studies with persons with incomplete spinal cord injury (iSCI) in terms of locomotion performance during assisted gait, patient-robot adaptations, impact on ambulation and assessment of lower limb muscle strength and spasticity. Participants with iSCI received interventions with a hybrid bilateral exoskeleton for 4 days. Assessment of gait function revealed that patients improved the 6 min and 10 m walking tests after the intervention, and further improvements were observed 1 week after the intervention. Muscle examination revealed improvements in knee and hip sagittal muscle balance scores and decreased score in ankle extensor balance. It is concluded that improvements in biomechanical function of the knee joint after the tested overground hybrid gait trainer are coherent with improvements in gait performance. PMID:24860478

Development of countermeasures for medical problems encountered in space flight

NASA Astrophysics Data System (ADS)

Nicogossian, Arnauld E.; Rummel, John D.; Leveton, Lauren; Teeter, Ron

1992-08-01

By the turn of this century, long-duration space missions, either in low Earth orbit or for got early planetary missions, will become commonplace. From the physiological standpoint, exposure to the weightless environment results in changes in body function, some of which are adaptive in nature and some of which can be life threatening. Important issues such as environmental health, radiation protection, physical deconditioning, and bone and muscle loss are of concern to life scientists and mission designers. Physical conditioning techniques such as exercise are not sufficient to protect future space travellers. A review of past experience with piloted missions has shown that gradual breakdown in bone and muscle tissue, together with fluid losses, despite a vigorous exercise regimen can ultimately lead to increased evidence of renal stones, musculoskeletal injuries, and bone fractures. Biological effects of radiation can, over long periods of time increase the risk of cancer development. Today, a vigorous program of study on the means to provide a complex exercise regimen to the antigravity muscles and skeleton is under study. Additional evaluation of artificial gravity as a mechanism to counteract bone and muscle deconditioning and cardiovascular asthenia is under study. New radiation methods are being developed. This paper will deal with the results of these studies.

Mechanics without Muscles: Fast Motion of the Venus flytrap and Bio-inspired Robotics

NASA Astrophysics Data System (ADS)

Chen, Zi; Guo, Qiaohang; Zheng, Huang; Li, Wei; Ding, Yiting; Su, Guiping; Lin, Junjie; Liu, Yuxin; Chen, Wenzhe; Taber, Larry

2013-03-01

The rapid motion of plants has intrigued scientists for centuries. Plants have neither nerves nor muscles, yet the Venus flytrap can move in a fraction of a second to capture insects. Darwin did a first systematic study on the trap closure mechanism, and called this plant ``one of the most wonderful in the world''. Several physical mechanisms have since been proposed, such as the rapid loss of turgor pressure, an irreversible acid-induced wall loosening mechanism, and tsnap-through instability, but no unanimous agreement is reached. We propose a coupled mechanical bistable mechanism that explains the rapid closure of the Venus flytrap, consistent with experimental observations. Such bistable behaviors are theoretically modeled and validated with experiments. Biomimetic flytrap robots are also fabricated according to the learnt principles. It is thus promising to design smart bio-mimetic materials and devices with snapping mechanisms as sensors, actuators, artificial muscles and biomedical devices. Zi Chen and Qiaohang Guo contributed equally. We thank National Science Foundation of China (No. 11102040), American Academy of Mechanics Founder's Award and Society in Science-Branco Weiss fellowship.

Bisphenol A and estradiol impede myoblast differentiation through down-regulating Akt signaling pathway.

PubMed

Go, Ga-Yeon; Lee, Sang-Jin; Jo, Ayoung; Lee, Jae-Rin; Kang, Jong-Sun; Yang, Mihi; Bae, Gyu-Un

2018-04-20

Bisphenol A (BPA), one of the most widespread endocrine disrupting chemicals, is known as an artificial estrogen, which interacts with estrogen receptor (ER). In this study, we investigated the effects of BPA and estradiol on myoblast differentiation and the underlying signaling mechanism. Exposure to BPA (0.01-1 μM) in mouse myoblast C2C12 cells attenuated myogenic differentiation via the reduced expression of muscle-specific genes, such as myosin heavy chain (MHC), MyoD, and Myogenin, without the alteration of cell proliferation and viability. BPA-exposed C2C12 myoblasts also showed a reduction of Akt phosphorylation ((37-61) %, p < 0.001), a key event for myogenesis. Similarly to BPA, estradiol (0.01-1 μM) reduced the expression of muscle-specific proteins and the formation of multinucleated myotubes, and attenuated the muscle differentiation-specific phosphorylation of Akt ((42-59) %, p < 0.001). We conclude that BPA and estradiol suppress myogenic differentiation through the inhibition of Akt signaling. Copyright © 2018 Elsevier B.V. All rights reserved.

Removal of muscle artifact from EEG data: comparison between stochastic (ICA and CCA) and deterministic (EMD and wavelet-based) approaches

NASA Astrophysics Data System (ADS)

Safieddine, Doha; Kachenoura, Amar; Albera, Laurent; Birot, Gwénaël; Karfoul, Ahmad; Pasnicu, Anca; Biraben, Arnaud; Wendling, Fabrice; Senhadji, Lotfi; Merlet, Isabelle

2012-12-01

Electroencephalographic (EEG) recordings are often contaminated with muscle artifacts. This disturbing myogenic activity not only strongly affects the visual analysis of EEG, but also most surely impairs the results of EEG signal processing tools such as source localization. This article focuses on the particular context of the contamination epileptic signals (interictal spikes) by muscle artifact, as EEG is a key diagnosis tool for this pathology. In this context, our aim was to compare the ability of two stochastic approaches of blind source separation, namely independent component analysis (ICA) and canonical correlation analysis (CCA), and of two deterministic approaches namely empirical mode decomposition (EMD) and wavelet transform (WT) to remove muscle artifacts from EEG signals. To quantitatively compare the performance of these four algorithms, epileptic spike-like EEG signals were simulated from two different source configurations and artificially contaminated with different levels of real EEG-recorded myogenic activity. The efficiency of CCA, ICA, EMD, and WT to correct the muscular artifact was evaluated both by calculating the normalized mean-squared error between denoised and original signals and by comparing the results of source localization obtained from artifact-free as well as noisy signals, before and after artifact correction. Tests on real data recorded in an epileptic patient are also presented. The results obtained in the context of simulations and real data show that EMD outperformed the three other algorithms for the denoising of data highly contaminated by muscular activity. For less noisy data, and when spikes arose from a single cortical source, the myogenic artifact was best corrected with CCA and ICA. Otherwise when spikes originated from two distinct sources, either EMD or ICA offered the most reliable denoising result for highly noisy data, while WT offered the better denoising result for less noisy data. These results suggest that the performance of muscle artifact correction methods strongly depend on the level of data contamination, and of the source configuration underlying EEG signals. Eventually, some insights into the numerical complexity of these four algorithms are given.

BATMAV - A Bio-Inspired Micro-Aerial Vehicle for Flapping Flight

NASA Astrophysics Data System (ADS)

Bunget, Gheorghe

The main objective of the BATMAV project is the development of a biologically-inspired Micro Aerial Vehicle (MAV) with flexible and foldable wings for flapping flight. While flapping flight in MAV has been previously studied and a number of models were realized they usually had unfoldable wings actuated with DC motors and mechanical transmission to achieve flapping motion. This approach limits the system to a rather small number of degrees of freedom with little flexibility and introduces an additional disadvantage of a heavy flight platform. The BATMAV project aims at the development of a flight platform that features bat-inspired wings with smart materials-based flexible joints and artificial muscles, which has the potential to closely mimic the kinematics of the real mammalian flyer. The bat-like flight platform was selected after an extensive analysis of morphological and aerodynamic flight parameters of small birds, bats and large insects characterized by a superior maneuverability and wind gust rejection. Morphological and aerodynamic parameters were collected from existing literature and compared concluding that bat wing present a suitable platform that can be actuated efficiently using artificial muscles. Due to their wing camber variation, the bat species can operate effectively at a large range of speeds and exhibit a remarkably maneuverable and agile flight. Although numerous studies were recently investigated the flapping flight, flexible and foldable wings that reproduce the natural intricate and efficient flapping motion were not designed yet. A comprehensive analysis of flight styles in bats based on the data collected by Norberg (Norberg, 1976) and the engineering theory of robotic manipulators resulted in a 2 and 3-DOF models which managed to mimic the wingbeat cycle of the natural flyer. The flexible joints of the 2 and 2-DOF models were replicated using smart materials like superelastic Shape Memory Alloys (SMA). The results of these kinematic models can be used to optimize the lengths and the attachment locations of the actuator muscle-wires such that enough lift, thrust and wing stroke are obtained. Bat skeleton measurements were taken from real bats and modeled in SolidWorks to accurately reproduce bones and body via rapid prototyping methods. Much attention was paid specifically to achieving the comparable strength, elasticity, and range of motion of a naturally occurring bat. The wing joints of the BATMAV platform were fabricated using superelastic Shape Memory Alloys (SMA), a key technology for the development of an engineering skeleton structure. This has enabled a simple and straightforward connection between different bones while at the same time has preserved the full range of functionality of the natural role model. Therefore, several desktop models were designed, fabricated and assembled in order to study various materials used in design phase. As a whole, the BATMAV project consists of four major stages of development: the current phase -- design and fabrication of the skeletal structure of the flight platform, selection and testing different materials for the design of a compliant bat-like membrane, analysis of the kinematics and kinetics of bat flight in order to design a biomechanical muscle system for actuation, and design of the electrical control architecture to coordinate the platform flight.

Computational model of deformable lenses actuated by dielectric elastomers

NASA Astrophysics Data System (ADS)

Lu, Tongqing; Cai, Shengqiang; Wang, Huiming; Suo, Zhigang

2013-09-01

A recent design of deformable lens mimics the human eye, adjusting its focal length in response to muscle-like actuation. The artificial muscle is a membrane of a dielectric elastomer subject to a voltage. Here, we calculate the coupled and inhomogeneous deformation of the lens and the dielectric elastomer actuator by formulating a nonlinear boundary-value problem. We characterize the strain-stiffening elastomer with the Gent model and describe the voltage-induced deformation using the model of ideal dielectric elastomer. The computational predictions agree well with experimental data. We use the model to explore the space of parameters, including the prestretch of the membrane, the volume of the liquid in the lens, and the size of the dielectric elastomer actuator relative to the lens. We examine how various modes of failure limit the minimum radius of curvature.

The occurrence of nematodes of the genus Trichinella in wolves (Canis lupus) from the Bieszczady Mountains and Augustowska Forest in Poland.

PubMed

Bień, Justyna; Moskwa, Bożena; Goździk, Katarzyna; Cybulska, Aleksandra; Kornacka, Aleksandra; Welc, Mirosław; Popiołek, Marcin; Cabaj, Władysław

2016-11-15

The aim of the present study was to investigate the prevalence of Trichinella infection in wolves (Canis lupus) in two regions in Poland. Muscle samples were collected from 21 wolves between 1999 and 2015 and processed by artificial digestion. In two cases, the muscle larvae (ML) were obtained and stored in alcohol. ML were detected in 12 wolves and genotyped by multiplex PCR. Trichinella britovi was confirmed in 12 wolves (54.5%). The larval burdens in infected animals ranged from 0.009 to 27 larvae per gram. The high prevalence of Trichinella infection in wolves might suggest that this predator is a significant reservoir of Trichinella species in the sylvatic cycle in Poland. Copyright © 2016 Elsevier B.V. All rights reserved.

Reconstructing for joint angles on the shoulder and elbow from non-invasive electroencephalographic signals through electromyography

PubMed Central

Choi, Kyuwan

2013-01-01

In this study, first the cortical activities over 2240 vertexes on the brain were estimated from 64 channels electroencephalography (EEG) signals using the Hierarchical Bayesian estimation while 5 subjects did continuous arm reaching movements. From the estimated cortical activities, a sparse linear regression method selected only useful features in reconstructing the electromyography (EMG) signals and estimated the EMG signals of 9 arm muscles. Then, a modular artificial neural network was used to estimate four joint angles from the estimated EMG signals of 9 muscles: one for movement control and the other for posture control. The estimated joint angles using this method have the correlation coefficient (CC) of 0.807 (±0.10) and the normalized root-mean-square error (nRMSE) of 0.176 (±0.29) with the actual joint angles. PMID:24167469

An artificial pancreas provided a novel model of blood glucose level variability in beagles.

PubMed

Munekage, Masaya; Yatabe, Tomoaki; Kitagawa, Hiroyuki; Takezaki, Yuka; Tamura, Takahiko; Namikawa, Tsutomu; Hanazaki, Kazuhiro

2015-12-01

Although the effects on prognosis of blood glucose level variability have gained increasing attention, it is unclear whether blood glucose level variability itself or the manifestation of pathological conditions that worsen prognosis. Then, previous reports have not been published on variability models of perioperative blood glucose levels. The aim of this study is to establish a novel variability model of blood glucose concentration using an artificial pancreas. We maintained six healthy, male beagles. After anesthesia induction, a 20-G venous catheter was inserted in the right femoral vein and an artificial pancreas (STG-22, Nikkiso Co. Ltd., Tokyo, Japan) was connected for continuous blood glucose monitoring and glucose management. After achieving muscle relaxation, total pancreatectomy was performed. After 1 h of stabilization, automatic blood glucose control was initiated using the artificial pancreas. Blood glucose level varied for 8 h, alternating between the target blood glucose values of 170 and 70 mg/dL. Eight hours later, the experiment was concluded. Total pancreatectomy was performed for 62 ± 13 min. Blood glucose swings were achieved 9.8 ± 2.3 times. The average blood glucose level was 128.1 ± 5.1 mg/dL with an SD of 44.6 ± 3.9 mg/dL. The potassium levels after stabilization and at the end of the experiment were 3.5 ± 0.3 and 3.1 ± 0.5 mmol/L, respectively. In conclusion, the results of the present study demonstrated that an artificial pancreas contributed to the establishment of a novel variability model of blood glucose levels in beagles.

The design, hysteresis modeling and control of a novel SMA-fishing-line actuator

NASA Astrophysics Data System (ADS)

Xiang, Chaoqun; Yang, Hui; Sun, Zhiyong; Xue, Bangcan; Hao, Lina; Asadur Rahoman, M. D.; Davis, Steve

2017-03-01

Fishing line can be combined with shape memory alloy (SMA) to form novel artificial muscle actuators which have low cost, are lightweight and soft. They can be applied in bionic, wearable and rehabilitation robots, and can reduce system weight and cost, increase power-to-weight ratio and offer safer physical human-robot interaction. However, these actuators possess several disadvantages, for example fishing line based actuators possess low strength and are complex to drive, and SMA possesses a low percentage contraction and has high hysteresis. This paper presents a novel artificial actuator (known as an SMA-fishing-line) made of fishing line and SMA twisted then coiled together, which can be driven directly by an electrical voltage. Its output force can reach 2.65 N at 7.4 V drive voltage, and the percentage contraction at 4 V driven voltage with a 3 N load is 7.53%. An antagonistic bionic joint driven by the novel SMA-fishing-line actuators is presented, and based on an extended unparallel Prandtl-Ishlinskii (EUPI) model, its hysteresis behavior is established, and the error ratio of the EUPI model is determined to be 6.3%. A Joule heat model of the SMA-fishing-line is also presented, and the maximum error of the established model is 0.510 mm. Based on this accurate hysteresis model, a composite PID controller consisting of PID and an integral inverse (I-I) compensator is proposed and its performance is compared with a traditional PID controller through simulations and experimentation. These results show that the composite PID controller possesses higher control precision than basic PID, and is feasible for implementation in an SMA-fishing-line driven antagonistic bionic joint.

Superficial or deep implantation of motor nerve after denervation: an experimental study--superficial or deep implantation of motor nerve.

PubMed

Askar, Ibrahím; Sabuncuoglu, Bízden Tavíl

2002-01-01

Neurorraphy, conventional nerve grafting technique, and artificial nerve conduits are not enough for repair in severe injuries of peripheral nerves, especially when there is separation of motor nerve from muscle tissue. In these nerve injuries, reinnervation is indicated for neurotization. The distal end of a peripheral nerve is divided into fascicles and implanted into the aneural zone of target muscle tissue. It is not known how deeply fascicles should be implanted into muscle tissue. A comparative study of superficial and deep implantation of separated motor nerve into muscle tissue is presented in the gastrocnemius muscle of rabbits. In this experimental study, 30 white New Zealand rabbits were used and divided into 3 groups of 10 rabbits each. In the first group (controls, group I), only surgical exposure of the gastrocnemius muscle and motor nerve (tibial nerve) was done without any injury to nerves. In the superficial implantation group (group II), tibial nerves were separated and divided into their own fascicles. These fascicles were implanted superficially into the lateral head of gastrocnemius muscle-aneural zone. In the deep implantation group (group III), the tibial nerves were separated and divided into their own fascicles. These fascicles were implanted around the center of the muscle mass, into the lateral head of the gastrocnemius muscle-aneural zone. Six months later, histopathological changes and functional recovery of the gastrocnemius muscle were investigated. Both experimental groups had less muscular weight than in the control group. It was found that functional recovery was achieved in both experimental groups, and was better in the superficial implantation group than the deep implantation group. EMG recordings revealed that polyphasic and late potentials were frequently seen in both experimental groups. Degeneration and regeneration of myofibrils were observed in both experimental groups. New motor end-plates were formed in a scattered manner in both experimental groups. However, they were more dense in the superficial implantation group than the deep implantation group. It was concluded that superficial implantation has a more powerful contractile capacity than that of deep implantation. We believe that this might arise from the high activity of glycolytic enzymes in peripheral muscle fibers of gastrocnemius muscle, decrease in insufficient intramuscular guidance apparatus, and intramuscular microneuroma formation at the insufficient neuromuscular junction since the motor nerve had less route to muscle fibers. Copyright 2002 Wiley-Liss, Inc.

Arterial endothelial function measurement method and apparatus

DOEpatents

Maltz, Jonathan S; Budinger, Thomas F

2014-03-04

A "relaxoscope" (100) detects the degree of arterial endothelial function. Impairment of arterial endothelial function is an early event in atherosclerosis and correlates with the major risk factors for cardiovascular disease. An artery (115), such as the brachial artery (BA) is measured for diameter before and after several minutes of either vasoconstriction or vasorelaxation. The change in arterial diameter is a measure of flow-mediated vasomodification (FMVM). The relaxoscope induces an artificial pulse (128) at a superficial radial artery (115) via a linear actuator (120). An ultrasonic Doppler stethoscope (130) detects this pulse 10-20 cm proximal to the point of pulse induction (125). The delay between pulse application and detection provides the pulse transit time (PTT). By measuring PTT before (160) and after arterial diameter change (170), FMVM may be measured based on the changes in PTT caused by changes in vessel caliber, smooth muscle tone and wall thickness.

Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators

PubMed Central

Chen, Xi; Goodnight, Davis; Gao, Zhenghan; Cavusoglu, Ahmet H.; Sabharwal, Nina; DeLay, Michael; Driks, Adam; Sahin, Ozgur

2015-01-01

Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth's climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Here, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air–water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment. PMID:26079632

Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators

NASA Astrophysics Data System (ADS)

Chen, Xi; Goodnight, Davis; Gao, Zhenghan; Cavusoglu, Ahmet H.; Sabharwal, Nina; Delay, Michael; Driks, Adam; Sahin, Ozgur

2015-06-01

Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth's climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Here, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air-water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

A large-strain, fast-response, and easy-to-manufacture electrothermal actuator based on laser-reduced graphene oxide

NASA Astrophysics Data System (ADS)

Zhang, Tian-Yu; Wang, Qian; Deng, Ning-Qin; Zhao, Hai-Ming; Wang, Dan-Yang; Yang, Zhen; Liu, Ying; Yang, Yi; Ren, Tian-Ling

2017-09-01

In this paper, we have developed a high-performance graphene electrothermal actuator (ETA). The fabrication method is easy, fast, environmentally friendly, and suitable for preparing both large-size and miniature graphene ETAs. When applied with the driving voltage of 65 V, the graphene ETA achieves a large bending angle of 270° with a fast response of 8 s and the recovery process costs 19 s. The large bending deformation is reversible and can be precisely controlled by the driving voltage. A simple robotic hand prepared by using a single graphene ETA can hold the object, which is more than ten times the weight of itself. By virtue of its large-strain, fast response, and easy-to-manufacture, we believe that the graphene ETA has tremendous potential in extensive applications involving biomimetic robotics, artificial muscles, switches, and microsensors in both macroscopic and microscopic fields.

Ionic electroactive polymer artificial muscles in space applications.

PubMed

Punning, Andres; Kim, Kwang J; Palmre, Viljar; Vidal, Frédéric; Plesse, Cédric; Festin, Nicolas; Maziz, Ali; Asaka, Kinji; Sugino, Takushi; Alici, Gursel; Spinks, Geoff; Wallace, Gordon; Must, Indrek; Põldsalu, Inga; Vunder, Veiko; Temmer, Rauno; Kruusamäe, Karl; Torop, Janno; Kaasik, Friedrich; Rinne, Pille; Johanson, Urmas; Peikolainen, Anna-Liisa; Tamm, Tarmo; Aabloo, Alvo

2014-11-05

A large-scale effort was carried out to test the performance of seven types of ionic electroactive polymer (IEAP) actuators in space-hazardous environmental factors in laboratory conditions. The results substantiate that the IEAP materials are tolerant to long-term freezing and vacuum environments as well as ionizing Gamma-, X-ray, and UV radiation at the levels corresponding to low Earth orbit (LEO) conditions. The main aim of this material behaviour investigation is to understand and predict device service time for prolonged exposure to space environment.

Intrinsic aerobic capacity correlates with greater inherent mitochondrial oxidative and H2O2 emission capacities without major shifts in myosin heavy chain isoform.

PubMed

Seifert, Erin L; Bastianelli, Mark; Aguer, Céline; Moffat, Cynthia; Estey, Carmen; Koch, Lauren G; Britton, Steven L; Harper, Mary-Ellen

2012-11-01

Exercise capacity and performance strongly associate with metabolic and biophysical characteristics of skeletal muscle, factors that also relate to overall disease risk. Despite its importance, the exact mechanistic features that connect aerobic metabolism with health status are unknown. To explore this, we applied artificial selection of rats for intrinsic (i.e., untrained) aerobic treadmill running to generate strains of low- and high-capacity runners (LCR and HCR, respectively), subsequently shown to diverge for disease risk. Concurrent breeding of LCR and HCR per generation allows the lines to serve as reciprocal controls for unknown environmental changes. Here we provide the first direct evidence in mitochondria isolated from skeletal muscle that intrinsic mitochondrial capacity is higher in HCR rats. Maximal phosphorylating respiration was ~40% greater in HCR mitochondria, independent of substrate and without altered proton leak or major changes in protein levels or muscle fiber type, consistent with altered control of phosphorylating respiration. Unexpectedly, H(2)O(2) emission was ~20% higher in HCR mitochondria, due to greater reduction of more harmful reactive oxygen species to H(2)O(2); indeed, oxidative modification of mitochondrial proteins was lower. When the higher mitochondrial yield was considered, phosphorylating respiration and H(2)O(2) emission were 70-80% greater in HCR muscle. Greater capacity of HCR muscle for work and H(2)O(2) signaling may result in enhanced and more immediate cellular repair, possibly explaining lowered disease risks.

Beta-Adrenergic Receptor Population is Up-Regulated by Increased Cyclic Amp Concentration in Chicken Skeletal Muscle Cells in Culture

NASA Technical Reports Server (NTRS)

Young, Ronald B.; Bridge, Kristin Y.; Vaughn, Jeffrey R.

1999-01-01

Skeletal muscle hypertrophy is promoted in vivo by administration of beta-drenergic receptor (bAR) agonists. Chicken skeletal muscle cells were treated with 1 (mu)M isoproterenol, a strong bAR agonist, between days 7 and 10 in culture. bAR population increased by approximately 40% during this treatment; however, the ability of the cells to synthesize cyclic AMP (cAMP) was diminished by two-fold. The quantity of myosin heavy chain (MHC) was not affected. To understand further the relationship between intracellular cAMP levels, bAR population, and muscle protein accumulation, intracellular cAMP levels were artificially elevated by treatment with 0-10 uM forskolin for up to three days. The basal concentration of CAMP in forskolin-treated cells increased up to 7-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in bAR population, with a maximum increase of approximately 40-60% at 10 uM forskolin. A maximum increase of 40-50% in the quantity of MHC was observed at 0.2 uM forskolin, but higher concentrations of forskolin reduced the quantity of MHC back to control levels. At 0.2 uM forskolin, intracellular levels of cAMP were higher by approximately 35%, and the (beta)AR population was higher by approximately 30%. Neither the number of muscle nuclei fused into myotubes nor the percentage of nuclei in myotubes were affected by forskolin at any of the concentrations studied.

Anthropogenic changes in sodium affect neural and muscle development in butterflies

PubMed Central

Snell-Rood, Emilie C.; Espeset, Anne; Boser, Christopher J.; White, William A.; Smykalski, Rhea

2014-01-01

The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5–30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates. PMID:24927579

Anthropogenic changes in sodium affect neural and muscle development in butterflies.

PubMed

Snell-Rood, Emilie C; Espeset, Anne; Boser, Christopher J; White, William A; Smykalski, Rhea

2014-07-15

The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5-30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates.

Arsenic Exposure to Killifish During Embryogenesis Alters Muscle Development

PubMed Central

Gaworecki, Kristen M.; Chapman, Robert W.; Neely, Marion G.; D’Amico, Angela R.; Bain, Lisa J.

2012-01-01

Epidemiological studies have correlated arsenic exposure in drinking water with adverse developmental outcomes such as stillbirths, spontaneous abortions, neonatal mortality, low birth weight, delays in the use of musculature, and altered locomotor activity. Killifish (Fundulus heteroclitus) were used as a model to help to determine the mechanisms by which arsenic could impact development. Killifish embryos were exposed to three different sodium arsenite concentrations and were collected at 32 h post-fertilization (hpf), 42 hpf, 168 hpf, or < 24 h post-hatch. A killifish oligo microarray was developed and used to examine gene expression changes between control and 25-ppm arsenic-exposed hatchlings. With artificial neural network analysis of the transcriptomic data, accurate prediction of each group (control vs. arsenic-exposed embryos) was obtained using a small subset of only 332 genes. The genes differentially expressed include those involved in cell cycle, development, ubiquitination, and the musculature. Several of the genes involved in cell cycle regulation and muscle formation, such as fetuin B, cyclin D–binding protein 1, and CapZ, were differentially expressed in the embryos in a time- and dose-dependent manner. Examining muscle structure in the hatchlings showed that arsenic exposure during embryogenesis significantly reduces the average muscle fiber size, which is coupled with a significant 2.1- and 1.6-fold upregulation of skeletal myosin light and heavy chains, respectively. These findings collectively indicate that arsenic exposure during embryogenesis can initiate molecular changes that appear to lead to aberrant muscle formation. PMID:22058191

Effects of artificial gravity on the cardiovascular system: Computational approach

NASA Astrophysics Data System (ADS)

Diaz Artiles, Ana; Heldt, Thomas; Young, Laurence R.

2016-09-01

Artificial gravity has been suggested as a multisystem countermeasure against the negative effects of weightlessness. However, many questions regarding the appropriate configuration are still unanswered, including optimal g-level, angular velocity, gravity gradient, and exercise protocol. Mathematical models can provide unique insight into these questions, particularly when experimental data is very expensive or difficult to obtain. In this research effort, a cardiovascular lumped-parameter model is developed to simulate the short-term transient hemodynamic response to artificial gravity exposure combined with ergometer exercise, using a bicycle mounted on a short-radius centrifuge. The model is thoroughly described and preliminary simulations are conducted to show the model capabilities and potential applications. The model consists of 21 compartments (including systemic circulation, pulmonary circulation, and a cardiac model), and it also includes the rapid cardiovascular control systems (arterial baroreflex and cardiopulmonary reflex). In addition, the pressure gradient resulting from short-radius centrifugation is captured in the model using hydrostatic pressure sources located at each compartment. The model also includes the cardiovascular effects resulting from exercise such as the muscle pump effect. An initial set of artificial gravity simulations were implemented using the Massachusetts Institute of Technology (MIT) Compact-Radius Centrifuge (CRC) configuration. Three centripetal acceleration (artificial gravity) levels were chosen: 1 g, 1.2 g, and 1.4 g, referenced to the subject's feet. Each simulation lasted 15.5 minutes and included a baseline period, the spin-up process, the ergometer exercise period (5 minutes of ergometer exercise at 30 W with a simulated pedal cadence of 60 RPM), and the spin-down process. Results showed that the cardiovascular model is able to predict the cardiovascular dynamics during gravity changes, as well as the expected steady-state cardiovascular behavior during sustained artificial gravity and exercise. Further validation of the model was performed using experimental data from the combined exercise and artificial gravity experiments conducted on the MIT CRC, and these results will be presented separately in future publications. This unique computational framework can be used to simulate a variety of centrifuge configuration and exercise intensities to improve understanding and inform decisions about future implementation of artificial gravity in space.

Fabrication of Self-Healable and Patternable Polypyrrole/Agarose Hybrid Hydrogels for Smart Bioelectrodes.

PubMed

Park, Nokyoung; Chae, Seung Chul; Kim, Il Tae; Hur, Jaehyun

2016-02-01

We present a new class of electrically conductive, mechanically moldable, and thermally self-healable hybrid hydrogels. The hybrid gels consist of polypyrrole and agarose as the conductive component and self-healable matrix, respectively. By using the appropriate oxidizing agent under conditions of mild temperature, the polymerization of pyrrole occurred along the three-dimensional network of the agarose hydrogel matrix. In contrast to most commercially available hydrogels, the physical crosslinking of agarose gel allows for reversible gelation in the case of our hybrid gel, which could be manipulated by temperature variation, which controls the electrical on/off behavior of the hybrid gel electrode. Exploiting this property, we fabricated a hybrid conductive hydrogel electrode which also self-heals thermally. The novel composite material we report here will be useful for many technological and biological applications, especially in reactive biomimetic functions and devices, artificial muscles, smart membranes, smart full organic batteries, and artificial chemical synapses.

Total Artificial Heart Bridge to Transplantation for a Patient With Occult Intracardiac Malignancy: Case Report.

PubMed

Reich, H; Czer, L; Bannykh, S; De Robertis, M; Wolin, E; Amersi, F; Moriguchi, J; Kobashigawa, J; Arabia, F

2015-09-01

Malignancy is the leading cause of long-term morbidity and mortality after heart and other solid organ transplantation; therefore, great emphasis is placed on pre- and post-transplantation cancer screening. Even with meticulous screening during evaluation for heart transplant candidacy, an occult cancer may not be apparent. Here, we share the case of a 51-year-old man with refractory heart failure who underwent total artificial heart implantation as a bridge to transplantation with the surprise finding of an isolated deposit of metastatic carcinoid tumor nested within a left ventricular papillary muscle in his explanted heart. The primary ileal carcinoid tumor was identified and resected completely. After remaining cancer-free for 14 months, he was listed for heart transplantation and was transplanted 2 months later. He is currently 3.5 months out from heart transplantation and doing well, without evidence of recurring malignancy. Copyright © 2015 Elsevier Inc. All rights reserved.

Response of Ambulatory Human Subjects to Artificial Gravity (Short Radius Centrifugation)

NASA Technical Reports Server (NTRS)

Paloski, William H.; Arya, Maneesh; Newby, Nathaniel; Tucker, Jon-Michael; Jarchow, Thomas; Young, Laurence

2006-01-01

Prolonged exposure to microgravity results in significant adaptive changes, including cardiovascular deconditioning, muscle atrophy, bone loss, and sensorimotor reorganization, that place individuals at risk for performing physical activities after return to a gravitational environment. Planned missions to Mars include unprecedented hypogravity exposures that would likely result in unacceptable risks to crews. Artificial gravity (AG) paradigms may offer multisystem protection from the untoward effects of adaptation to the microgravity of space or the hypogravity of planetary surfaces. While the most effective AG designs would employ a rotating spacecraft, perceived issues may preclude their use. The questions of whether and how intermittent AG produced by a short radius centrifuge (SRC) could be employed have therefore sprung to the forefront of operational research. In preparing for a series of intermittent AG trials in subjects deconditioned by bed rest, we have examined the responses of several healthy, ambulatory subjects to SRC exposures.

Skeletal muscle

USDA-ARS?s Scientific Manuscript database

There are approximately 650-850 muscles in the human body these include skeletal (striated), smooth and cardiac muscle. The approximation is based on what some anatomists consider separate muscle or muscle systems. Muscles are classified based on their anatomy (striated vs. smooth) and if they are v...

Task constraints and minimization of muscle effort result in a small number of muscle synergies during gait.

PubMed

De Groote, Friedl; Jonkers, Ilse; Duysens, Jacques

2014-01-01

Finding muscle activity generating a given motion is a redundant problem, since there are many more muscles than degrees of freedom. The control strategies determining muscle recruitment from a redundant set are still poorly understood. One theory of motor control suggests that motion is produced through activating a small number of muscle synergies, i.e., muscle groups that are activated in a fixed ratio by a single input signal. Because of the reduced number of input signals, synergy-based control is low dimensional. But a major criticism on the theory of synergy-based control of muscles is that muscle synergies might reflect task constraints rather than a neural control strategy. Another theory of motor control suggests that muscles are recruited by optimizing performance. Optimization of performance has been widely used to calculate muscle recruitment underlying a given motion while assuming independent recruitment of muscles. If synergies indeed determine muscle recruitment underlying a given motion, optimization approaches that do not model synergy-based control could result in muscle activations that do not show the synergistic muscle action observed through electromyography (EMG). If, however, synergistic muscle action results from performance optimization and task constraints (joint kinematics and external forces), such optimization approaches are expected to result in low-dimensional synergistic muscle activations that are similar to EMG-based synergies. We calculated muscle recruitment underlying experimentally measured gait patterns by optimizing performance assuming independent recruitment of muscles. We found that the muscle activations calculated without any reference to synergies can be accurately explained by on average four synergies. These synergies are similar to EMG-based synergies. We therefore conclude that task constraints and performance optimization explain synergistic muscle recruitment from a redundant set of muscles.

Inter-tissue differences in fatty acid incorporation as a result of dietary oil manipulation in Port Jackson sharks (Heterodontus portusjacksoni).

PubMed

Beckmann, Crystal L; Mitchell, James G; Stone, David A J; Huveneers, Charlie

2014-06-01

Fatty acid profile analysis is a tool for dietary investigation that may complement traditional stomach contents analysis. While recent studies have shown that the liver of sharks fed different diets have differing fatty acid profiles, the degree to which diet is reflected in shark blood serum and muscle tissue is still poorly understood. An 18-week controlled feeding experiment was undertaken using captive Port Jackson sharks (Heterodontus portusjacksoni). Sharks were fed exclusive diets of artificial pellets treated with fish or poultry oil and sampled every 6 weeks. The fatty acid profiles from liver, blood serum, and muscle were affected differently, with the period from which significant differences were observed varying by tissue and diet type. The total fatty acid profiles of fish oil and poultry oil fed sharks were significantly different from week 12 onwards in the liver and blood serum, but significant differences were only observed by week 18 in the muscle tissue of sharks fed different diets. The drivers of dissimilarity which aligned with dietary input were 14:0, 18:2n-6, 20:5n-3, 18:1n-9 and 22:6n-3 in the liver and blood serum. Dietary fatty acids accumulated more consistently in the liver than in the blood plasma or muscle, likely due to its role as the central organ for fat processing and storage. Blood serum and muscle fatty acid profiles were influenced by diet, but fluctuated over-time. The low level of correlation between diet and muscle FA profiles is likely a result of low levels of fat (<1%) in the muscle and the domination of structural, cell-membrane phospholipids in shark muscle tissues. Our findings describe inter-tissue differences in the incorporation of fatty acids from the diet to consumer, which should be taken into account when interpreting dietary patterns from fatty acid profiles.

Beta-Adrenergic Receptor Expression in Muscle Cells

NASA Technical Reports Server (NTRS)

Young, Ronald B.; Bridge, K.; Vaughn, J. R.

1999-01-01

beta-adrenergic receptor (bAR) agonists presumably exert their physiological action on skeletal muscle cells through the bAR. Since the signal generated by the bAR is cyclic AMP (cAMP), experiments were initiated in primary chicken muscle cell cultures to determine if artificial elevation of intracellular cAMP by treatment with forskolin would alter the population of bAR expressed on the surface of muscle cells. Chicken skeletal muscle cells after 7 days in culture were employed for the experiments because muscle cells have attained a steady state with respect to muscle protein metabolism at this stage. Cells were treated with 0-10 uM forskolin for a total of three days. At the end of the 1, 2, and 3 day treatment intervals, the concentration of cAMP and the bAR population were measured. Receptor population was measured in intact muscle cell cultures as the difference between total binding of [H-3]CGP-12177 and non-specific binding of [H-3]CGP-12177 in the presence of 1 uM propranolol. Intracellular cAMP concentration was measured by radioimmunoassay. The concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in (beta)AR population, with a maximum increase of approximately 50% at 10 uM. This increase in (beta)AR population was apparent after only 1 day of treatment, and the pattern of increase was maintained for all 3 days of the treatment period. Thus, increasing the intracellular concentration of cAMP leads to up-regulation of (beta)AR population. Clenbuterol and isoproterenol gave similar effects on bAR population. The effect of forskolin on the quantity and apparent synthesis rate of the heavy chain of myosin (mhc) were also investigated. A maximum increase of 50% in the quantity of mhc was observed at 0.2 UM forskolin, but higher concentrations of forskolin reduced the quantity of mhc back to control levels.

Sensing magnetic flux density of artificial neurons with a MEMS device.

PubMed

Tapia, Jesus A; Herrera-May, Agustin L; García-Ramírez, Pedro J; Martinez-Castillo, Jaime; Figueras, Eduard; Flores, Amira; Manjarrez, Elías

2011-04-01

We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh-Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezoresistive sensing elements, which need an easy fabrication process. The proposed microsensor has a resolution of 80 nT, a sensitivity of 1.2 V.T(-1), a resonant frequency of 13.87 kHz, low power consumption (2.05 mW), quality factor of 93 at atmospheric pressure, and requires a simple signal processing circuit. The importance of our study is twofold. First, because the artificial neuron can generate well-controlled magnetic flux density, we suggest it could be used to analyze the resolution and performance of different magnetic field sensors intended for neurobiological applications. Second, the introduced MEMS magnetic field sensor may be used as a prototype to develop new high-resolution biomedical microdevices to sense magnetic fields from cardiac tissue, nerves, spinal cord, or the brain.

Occurrence and genotypic analysis of Trichinella species in Alaska marine-associated mammals of the Bering and Chukchi seas.

PubMed

Seymour, J; Horstmann-Dehn, L; Rosa, C; Lopez, J A

2014-02-24

The zoonotic parasite Trichinella is the causative agent of trichinellosis outbreaks in the circumpolar Arctic. Subsistence communities are particularly prone to trichinellosis due to traditional meat preparation methods and regional presence of a freeze-tolerant Trichinella species (Trichinella nativa). This study is the first application of a validated artificial digestion method in determining incidence of Trichinella sp. in Alaskan mammals. Infection incidence in pinniped species (Erignathus barbatus, Eumetopias jubatus, Odobenus rosmarus divergens, and Pusa hispida) was low, with only 1/57 ringed seals infected. Polymerase Chain Reaction assays indicate T. nativa as the only species present in northern Alaska. Analysis of an archived polar bear (Ursus maritimus) muscle sample shows freeze-tolerance and longevity for T. nativa to -20°C for 10 years and short-term freeze resistance to -80°C when morphology was used to determine presence of live larvae. However, larval motility suggests 0% survival. An approach that combines artificial digestion with PCR based species identification has excellent potential for Trichinella sp. detection and identification of archived tissues. Overall, Trichinella in Alaskan mammals, particularly marine mammals of subsistence importance, appears to be a minor problem. These modern diagnostic techniques provide accurate insight into the presence of Trichinella in the Alaskan marine environment. Copyright © 2013 Elsevier B.V. All rights reserved.

Targeted Muscle Reinnervation for Real-Time Myoelectric Control of Multifunction Artificial Arms

PubMed Central

Kuiken, Todd A.; Li, Guanglin; Lock, Blair A.; Lipschutz, Robert D.; Miller, Laura A.; Stubblefield, Kathy A.; Englehart, Kevin

2011-01-01

Context Improving the function of prosthetic arms remains a challenge, as access to the neural control information for the arm is lost during amputation. We have developed a surgical technique called targeted muscle reinnervation (TMR) which transfers residual arm nerves to alternative muscle sites. After reinnervation, these target muscles produce an electromyogram (EMG) on the surface of the skin that can be measured and used to control prosthetic arms. Objective Assess the performance of TMR upper-limb amputee patients using a pattern-recognition algorithm to decode EMG signals and control prosthetic arm motions. Design Surface EMG signals were recorded on participants and decoded using a pattern-recognition algorithm. The decoding program controlled the movement of a virtual prosthetic arm. Participants were instructed to perform various arm movements, and their abilities to control the virtual prosthetic arm were measured. In addition, TMR patients used the same control system to operate advanced arm prosthesis prototypes. Setting This study was conducted between January 2007 and January 2008 at the Rehabilitation Institute of Chicago. Participants This study included five patients with shoulder disarticulation or transhumeral amputations who received TMR surgery between February 2002 and October 2006. It also included five non-amputee (control) participants. Main Outcome Measure Performance metrics measured during virtual arm movements included motion-selection time, motion-completion time, and motion-completion (or `success') rate. Three of the TMR patients were also able to test advanced arm prostheses. Results TMR patients were able to repeatedly perform 10 different elbow, wrist and hand motions with the virtual prosthetic arm. For TMR patients, the average (standard deviation (SD)) motion-selection and motion-completion times for elbow and wrist movements were 0.22 s (0.06) and 1.29 s (0.15), respectively. These times were 0.06 s and 0.21 s longer than the average times of control participants. For TMR patients, the average (SD) motion-selection and motion-completion times for hand-grasp patterns were 0.38 s (0.12) and 1.54 s (0.27), respectively. TMR patients successfully completed an average (SD) of 96.3% (3.8) of elbow and wrist movements and 86.9% (13.9) of hand movements within 5 s, compared to 100% (0) and 96.7% (4.7) completed by controls. Three of the patients were able to demonstrate the use of this control system in advanced prostheses including motorized shoulders, elbows, wrists and hands. Conclusion These results suggest that reinnervated muscles can produce sufficient EMG information to control advanced artificial arms. PMID:19211469

Artificial Intelligence Project

DTIC Science & Technology

1990-01-01

Artifcial Intelligence Project at The University of Texas at Austin, University of Texas at Austin, Artificial Intelligence Laboratory AITR84-01. Novak...Texas at Austin, Artificial Intelligence Laboratory A187-52, April 1987. Novak, G. "GLISP: A Lisp-Based Programming System with Data Abstraction...of Texas at Austin, Artificial Intelligence Laboratory AITR85-14.) Rim, Hae-Chang, and Simmons, R. F. "Extracting Data Base Knowledge from Medical

Non-Intrusive Gaze Tracking Using Artificial Neural Networks

DTIC Science & Technology

1994-01-05

We have developed an artificial neural network based gaze tracking, system which can be customized to individual users. A three layer feed forward...empirical analysis of the performance of a large number of artificial neural network architectures for this task. Suggestions for further explorations...for neurally based gaze trackers are presented, and are related to other similar artificial neural network applications such as autonomous road following.

Parallel evolution of tetrodotoxin resistance in three voltage-gated sodium channel genes in the garter snake Thamnophis sirtalis.

PubMed

McGlothlin, Joel W; Chuckalovcak, John P; Janes, Daniel E; Edwards, Scott V; Feldman, Chris R; Brodie, Edmund D; Pfrender, Michael E; Brodie, Edmund D

2014-11-01

Members of a gene family expressed in a single species often experience common selection pressures. Consequently, the molecular basis of complex adaptations may be expected to involve parallel evolutionary changes in multiple paralogs. Here, we use bacterial artificial chromosome library scans to investigate the evolution of the voltage-gated sodium channel (Nav) family in the garter snake Thamnophis sirtalis, a predator of highly toxic Taricha newts. Newts possess tetrodotoxin (TTX), which blocks Nav's, arresting action potentials in nerves and muscle. Some Thamnophis populations have evolved resistance to extremely high levels of TTX. Previous work has identified amino acid sites in the skeletal muscle sodium channel Nav1.4 that confer resistance to TTX and vary across populations. We identify parallel evolution of TTX resistance in two additional Nav paralogs, Nav1.6 and 1.7, which are known to be expressed in the peripheral nervous system and should thus be exposed to ingested TTX. Each paralog contains at least one TTX-resistant substitution identical to a substitution previously identified in Nav1.4. These sites are fixed across populations, suggesting that the resistant peripheral nerves antedate resistant muscle. In contrast, three sodium channels expressed solely in the central nervous system (Nav1.1-1.3) showed no evidence of TTX resistance, consistent with protection from toxins by the blood-brain barrier. We also report the exon-intron structure of six Nav paralogs, the first such analysis for snake genes. Our results demonstrate that the molecular basis of adaptation may be both repeatable across members of a gene family and predictable based on functional considerations. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors.

PubMed

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2010-10-21

Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73%. The results show that the MFL and FD of a single channel sEMG recorded from the forearm can be used to accurately identify a set of finger and wrist flexions even when the muscle activity is very weak. A comparison with other features demonstrates that this feature set offers a dramatic improvement in the accuracy of identification of the wrist and finger movements. It is proposed that such a system could be used to control a prosthetic hand or for a human computer interface.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

PubMed Central

2010-01-01

Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73%. Conclusions The results show that the MFL and FD of a single channel sEMG recorded from the forearm can be used to accurately identify a set of finger and wrist flexions even when the muscle activity is very weak. A comparison with other features demonstrates that this feature set offers a dramatic improvement in the accuracy of identification of the wrist and finger movements. It is proposed that such a system could be used to control a prosthetic hand or for a human computer interface. PMID:20964863

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasgupta, Jaydip; Elliott, Ruth A.; Doshani, Angie

Introduction: Consumption of carbonated soft drinks has been shown to be independently associated with the development of overactive bladder symptoms (OR 1.62, 95% CI 1.18, 2.22) [Dallosso, H.M., McGrother, C.W., Matthews, R.J., Donaldson, M.M.K., 2003. The association of diet and other lifestyle factors with overactive bladder and stress incontinence: a longitudinal study in women. BJU Int. 92, 69-77]. We evaluated the effects of three artificial sweeteners, acesulfame K, aspartame and sodium saccharin, on the contractile response of isolated rat detrusor muscle strips. Methods: Strips of detrusor muscle were placed in an organ bath and stimulated with electrical field stimulation (EFS)more » in the absence and presence of atropine, and with {alpha},{beta} methylene ATP, potassium, calcium and carbachol. Results: Sweeteners 10{sup -7} M to 10{sup -2} M enhanced the contractile response to 10 Hz EFS compared to control (p < 0.01). The atropine-resistant response to EFS was marginally increased by acesulfame K 10{sup -6} M, aspartame 10{sup -7} M and sodium saccharin 10{sup -7} M. Acesulfame K 10{sup -6} M increased the maximum contractile response to {alpha},{beta} methylene ATP by 35% ({+-} 9.6%) (p < 0.05) and to KCl by 12% ({+-} 3.1%) (p < 0.01). Sodium saccharin also increased the response to KCl by 37% ({+-} 15.2%) (p < 0.05). These sweeteners shifted the calcium concentration-response curves to the left. Acesulfame K 10{sup -6} M increased the log EC{sub 5} from -2.79 ({+-} 0.037) to -3.03 ({+-} 0.048, p < 0.01) and sodium saccharin 10{sup -7} M from -2.74 ({+-} 0.03) to 2.86 ({+-} 0.031, p < 0.05). The sweeteners had no significant effect on the contractile response to carbachol but they did increase the amplitude of spontaneous bladder contractions. Discussion: These results suggest that low concentrations of artificial sweeteners enhanced detrusor muscle contraction via modulation of L-type Ca{sup +2} channels.« less

Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease: A review of the English-language literature.

PubMed

De Brandt, Jana; Spruit, Martijn A; Hansen, Dominique; Franssen, Frits Me; Derave, Wim; Sillen, Maurice Jh; Burtin, Chris

2018-05-01

Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcome measures. This review uses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies ( n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, and water-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients.

Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease: A review of the English-language literature

PubMed Central

De Brandt, Jana; Spruit, Martijn A; Hansen, Dominique; Franssen, Frits ME; Derave, Wim; Sillen, Maurice JH; Burtin, Chris

2017-01-01

Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcome measures. This review uses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies (n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, and water-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients. PMID:28580854

Functional adaptation of the masticatory system to implant-supported mandibular overdentures.

PubMed

Giannakopoulos, Nikolaos Nikitas; Corteville, Frédéric; Kappel, Stefanie; Rammelsberg, Peter; Schindler, Hans Jürgen; Eberhard, Lydia

2017-05-01

The purpose of this study was to investigate the adaptation behavior of the stomatognathic system after immediate loading (24 to 72 h after surgery) of two implants supporting mandibular overdentures, assessed on insertion and three months later. The study hypothesis was that insertion of the overdentures would significantly change masticatory performance and muscle activity at both times. Thirty subjects (nine female, mean age 69.64 ± 11.81 years; 21 male, mean age 68.67 ± 7.41 years) who participated in a randomized clinical trial were included in the study. Each patient was examined three times: (i) at baseline, after already having worn new dentures for three months (T1); (ii) immediately after insertion of the overdentures on the implants (T2); and (iii) after an adaptation period of three months (T3). Examination comprised assessment of masticatory performance with artificial test food (Optocal), and simultaneous bilateral surface EMG recording of the masseter and anterior temporalis muscles. Particle-size distribution (representative value X 50 ), maximum muscle contraction (MVC), and total muscle work (TMW; area under the curve) were compared by use of repeated-measures analysis of variance (ANOVA). At T3, all measured variables (i.e., masticatory performance and muscle activity) were significantly different from those at T1. At T2, no significant changes were observed. The study hypothesis had to be rejected for T2 but accepted for T3. Functional rehabilitation (in terms of masticatory performance and masticatory muscle activity) does not occur immediately after immediate loading of two implants with mandibular overdentures, but requires a significant time for functional improvement. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sensory synergy as environmental input integration

PubMed Central

Alnajjar, Fady; Itkonen, Matti; Berenz, Vincent; Tournier, Maxime; Nagai, Chikara; Shimoda, Shingo

2015-01-01

The development of a method to feed proper environmental inputs back to the central nervous system (CNS) remains one of the challenges in achieving natural movement when part of the body is replaced with an artificial device. Muscle synergies are widely accepted as a biologically plausible interpretation of the neural dynamics between the CNS and the muscular system. Yet the sensorineural dynamics of environmental feedback to the CNS has not been investigated in detail. In this study, we address this issue by exploring the concept of sensory synergy. In contrast to muscle synergy, we hypothesize that sensory synergy plays an essential role in integrating the overall environmental inputs to provide low-dimensional information to the CNS. We assume that sensor synergy and muscle synergy communicate using these low-dimensional signals. To examine our hypothesis, we conducted posture control experiments involving lateral disturbance with nine healthy participants. Proprioceptive information represented by the changes on muscle lengths were estimated by using the musculoskeletal model analysis software SIMM. Changes on muscles lengths were then used to compute sensory synergies. The experimental results indicate that the environmental inputs were translated into the two dimensional signals and used to move the upper limb to the desired position immediately after the lateral disturbance. Participants who showed high skill in posture control were found to be likely to have a strong correlation between sensory and muscle signaling as well as high coordination between the utilized sensory synergies. These results suggest the importance of integrating environmental inputs into suitable low-dimensional signals before providing them to the CNS. This mechanism should be essential when designing the prosthesis' sensory system to make the controller simpler. PMID:25628523

An improved simulation based biomechanical model to estimate static muscle loadings

NASA Technical Reports Server (NTRS)

Rajulu, Sudhakar L.; Marras, William S.; Woolford, Barbara

1991-01-01

The objectives of this study are to show that the characteristics of an intact muscle are different from those of an isolated muscle and to describe a simulation based model. This model, unlike the optimization based models, accounts for the redundancy in the musculoskeletal system in predicting the amount of forces generated within a muscle. The results of this study show that the loading of the primary muscle is increased by the presence of other muscle activities. Hence, the previous models based on optimization techniques may underestimate the severity of the muscle and joint loadings which occur during manual material handling tasks.

Was Cheselden's One-Century-Long Otological Writings Concordant With His Time?

PubMed

Corrales, C Eduardo; Mudry, Albert

2015-08-01

William Cheselden's famous anatomical treatise spanned the entire 18th century period with its 15 editions. The aim of this study is to analyze the otological knowledge described in all these editions, to identify key 18th century otological advancements, and to study their concordance.In the first edition (1713), Cheselden notably mentioned four middle ear ossicles: malleus, incus, fourth ossicle, and stapes; four auditory muscles: "external tympani," "external oblique," tensor tympani, and stapedial; and a small opening in the tympanic membrane. In subsequent editions, minimal changes appeared, except for nomenclature changes and the proposal of an artificial opening of the tympanic membrane. Virtually no changes were performed up to the last edition (1806). All Cheselden's Editions confirm the uncertain presence of a fourth ossicle, the disputable presence of a tympanic membrane opening and the "usual" accepted presence of three muscles to the malleus. Key otologic advancements, not found in any of Cheselden's writings, were catherization of the Eustachian tube, presence of fluid in the inner ear, and the surgical opening of the mastoid.This study demonstrates that Cheselden, and his subsequent editors, were unaware of some important otologic developments that revolutionized the field of otology. Description of key advancements lacking in his treatise includes catherization of the Eustachian tube, the presence of fluid in the inner ear, and the surgical opening of the mastoid. Nevertheless, Cheselden is first in proposing to artificially open the tympanic membrane in humans.

Electrical Stimulation of Artificial Heart Muscle: A Look Into the Electrophysiologic and Genetic Implications.

PubMed

Mohamed, Mohamed A; Islas, Jose F; Schwartz, Robert J; Birla, Ravi K

Development of tissue-engineered hearts for treatment of myocardial infarction or biologic pacemakers has been hindered by the production of mostly arrhythmic or in-synergistic constructs. Electrical stimulation (ES) of these constructs has been shown to produce tissues with greater twitch force and better adrenergic response. To further our understanding of the mechanisms underlying the effect of ES, we fabricated a bioreactor capable of delivering continuous or intermittent waveforms of various types to multiple constructs simultaneously. In this study, we examined the effect of an intermittent biphasic square wave on our artificial heart muscle (AHM) composed of neonatal rat cardiac cells and fibrin gel. Twitch forces, spontaneous contraction rates, biopotentials, gene expression profiles, and histologic observations were examined for the ES protocol over a 12 day culture period. We demonstrate improved consistency between samples for twitch force and contraction rate, and higher normalized twitch force amplitudes for electrically stimulated AHMs. Improvements in electrophysiology within the AHM were noted by higher conduction velocities and lower latency in electrical response for electrically stimulated AHMs. Genes expressing key electrophysiologic and structural markers peaked at days 6 and 8 of culture, only a few days after the initiation of ES. These results may be used for optimization strategies to establish protocols for producing AHMs capable of replacing damaged heart tissue in either a contractile or electrophysiologic capacity. Optimized AHMs can lead to alternative treatments to heart failure and alleviate the limited donor supply crisis.

Electrical Stimulation of Artificial Heart Muscle: a look into the electrophysiological and genetic implications

PubMed Central

Mohamed, Mohamed A; Islas, Jose F; Schwartz, Robert J; Birla, Ravi K

2016-01-01

Development of tissue-engineered hearts for treatment of myocardial infarction or biological pacemakers has been hindered by the production of mostly arrhythmic or in-synergistic constructs. Electrical stimulation (ES) of these constructs has been shown to produce tissues with greater twitch force and better adrenergic response. In order to further our understanding of the mechanisms underlying the effect of ES, we fabricated a bioreactor capable of delivering continuous or intermittent waveforms of various types to multiple constructs simultaneously. In this study, we examined the effect of an intermittent biphasic square wave on our artificial heart muscle (AHM) composed of neonatal rat cardiac cells and fibrin gel. Twitch forces, spontaneous contraction rates, biopotentials, gene expression profiles, and histological observations were examined for the ES protocol over a 12 day culture period. We demonstrate improved consistency between samples for twitch force and contraction rate, and higher normalized twitch force amplitudes for electrically stimulated AHM. Improvements in electrophysiology within the AHM was noted by higher conduction velocities and lower latency in electrical response for electrically stimulated AHM. Genes expressing key electrophysiological and structural markers peaked at days 6 and 8 of culture, only a few days after the initiation of ES. These results may be used for optimization strategies to establish protocols for producing AHM capable of replacing damaged heart tissue in either a contractile or electrophysiological capacity. Optimized AHM can lead to alternative treatments to heart failure and alleviate the limited donor supply crisis. PMID:28459744

Dynamic bending of bionic flexible body driven by pneumatic artificial muscles(PAMs) for spinning gait of quadruped robot

NASA Astrophysics Data System (ADS)

Lei, Jingtao; Yu, Huangying; Wang, Tianmiao

2016-01-01

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depends on the mechanical properties of the body mechanism. It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles(PAMs). This kind of body imitates the four-legged creatures' kinematical structure and physical properties, which has the characteristic of changeable stiffness, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving force of PAM is determined. The experiment of body bending is conducted, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18°. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Morphological Computation of Haptic Perception of a Controllable Stiffness Probe.

PubMed

Sornkarn, Nantachai; Dasgupta, Prokar; Nanayakkara, Thrishantha

2016-01-01

When people are asked to palpate a novel soft object to discern its physical properties such as texture, elasticity, and even non-homogeneity, they not only regulate probing behaviors, but also the co-contraction level of antagonistic muscles to control the mechanical impedance of fingers. It is suspected that such behavior tries to enhance haptic perception by regulating the function of mechanoreceptors at different depths of the fingertips and proprioceptive sensors such as tendon and spindle sensors located in muscles. In this paper, we designed and fabricated a novel two-degree of freedom variable stiffness indentation probe to investigate whether the regulation of internal stiffness, indentation, and probe sweeping velocity (PSV) variables affect the accuracy of the depth estimation of stiff inclusions in an artificial silicon phantom using information gain metrics. Our experimental results provide new insights into not only the biological phenomena of haptic perception but also new opportunities to design and control soft robotic probes.

Heart Research

NASA Technical Reports Server (NTRS)

1991-01-01

James Antaki and a group of researchers from the University of Pittsburgh School of Medicine used many elements of the Technology Utilization Program while looking for a way to visualize and track material points within the heart muscle. What they needed were tiny artificial "eggs" containing copper sulfate solution, small enough (about 2 mm in diameter) that they would not injure the heart, and large enough to be seen in Magnetic Resonance Imaging (MRI) images; they also had to be biocompatible and tough enough to withstand the beating of the muscle. The group could not make nor buy sufficient containers. After reading an article on microspheres in NASA Tech Briefs, and a complete set of reports on microencapsulation from the Jet Propulsion Laboratory (JPL), JPL put Antaki in touch with Dr.Taylor Wang of Vanderbilt University who helped construct the myocardial markers. The research is expected to lead to improved understanding of how the heart works and what takes place when it fails.

Kudoa spp. (Myxozoa) infection in musculature of Plagioscion squamosissimus (Sciaenidae) in the Amazon region, Brazil.

PubMed

de Oliveira, Joyce Cardim; Velasco, Michele; dos Santos, Patrícia de Fátima Sacco; Silva, José Mauro Viana; Clemente, Sérgio Carmona de São; Matos, Edilson

2015-01-01

Ninety specimens of Plagioscion squamosissimus captured using fishing tackle in the Outeiro district, state of Pará, were examined. Fish were placed in plastic bags containing water, under conditions of artificial aeration, and transported live to the Carlos Azevedo Research Laboratory (LPCA), in Belém, Pará. They were anesthetized, euthanized and necropsied; small fragments of the epaxial and hypaxial muscles were removed for examination of fresh histological sections by means of optical microscopy. In 100% of the specimens analyzed, parasitic pseudocysts were seen to be interspersed within and between the skeletal muscle. These contained pseudoquadrate and/or star-shaped spores that presented four valves and four polar capsules, which were identified from their morphology as belonging to the genus Kudoa. This is the first report of Kudoa in P. squamosissimus in the Amazon region, Pará, Brazil.

Rehabilitation Nutrition for Possible Sarcopenic Dysphagia After Lung Cancer Surgery: A Case Report.

PubMed

Wakabayashi, Hidetaka; Uwano, Rimiko

2016-06-01

Sarcopenic dysphagia is characterized by the loss of swallowing muscle mass and function associated with generalized loss of skeletal muscle mass and function. In this report, the authors describe a patient with possible sarcopenic dysphagia after lung cancer surgery and was treated subsequently by rehabilitation nutrition. A 71-year-old man with lung cancer experienced complications of an acute myocardial infarction and pneumonia after surgery. He was ventilated artificially, and a tracheotomy was performed. The patient received diagnoses of malnutrition, severe sarcopenia, and possible sarcopenic dysphagia. His dysphagia was improved by a combination of dysphagia rehabilitation including physical and speech therapy and an improvement in nutrition initiated by a nutrition support team. Finally, he no longer had dysphagia and malnutrition. Sarcopenic dysphagia should be considered in patients with sarcopenia and dysphagia. Rehabilitation nutrition using a combination of both rehabilitation and nutritional care management is presumptively useful for treating sarcopenic dysphagia.

Memory and learning behaviors mimicked in nanogranular SiO2-based proton conductor gated oxide-based synaptic transistors

NASA Astrophysics Data System (ADS)

Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

2013-10-01

In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements.In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr02987e

A genome-wide scan for signatures of differential artificial selection in ten cattle breeds.

PubMed

Rothammer, Sophie; Seichter, Doris; Förster, Martin; Medugorac, Ivica

2013-12-21

Since the times of domestication, cattle have been continually shaped by the influence of humans. Relatively recent history, including breed formation and the still enduring enormous improvement of economically important traits, is expected to have left distinctive footprints of selection within the genome. The purpose of this study was to map genome-wide selection signatures in ten cattle breeds and thus improve the understanding of the genome response to strong artificial selection and support the identification of the underlying genetic variants of favoured phenotypes. We analysed 47,651 single nucleotide polymorphisms (SNP) using Cross Population Extended Haplotype Homozygosity (XP-EHH). We set the significance thresholds using the maximum XP-EHH values of two essentially artificially unselected breeds and found up to 229 selection signatures per breed. Through a confirmation process we verified selection for three distinct phenotypes typical for one breed (polledness in Galloway, double muscling in Blanc-Bleu Belge and red coat colour in Red Holstein cattle). Moreover, we detected six genes strongly associated with known QTL for beef or dairy traits (TG, ABCG2, DGAT1, GH1, GHR and the Casein Cluster) within selection signatures of at least one breed. A literature search for genes lying in outstanding signatures revealed further promising candidate genes. However, in concordance with previous genome-wide studies, we also detected a substantial number of signatures without any yet known gene content. These results show the power of XP-EHH analyses in cattle to discover promising candidate genes and raise the hope of identifying phenotypically important variants in the near future. The finding of plausible functional candidates in some short signatures supports this hope. For instance, MAP2K6 is the only annotated gene of two signatures detected in Galloway and Gelbvieh cattle and is already known to be associated with carcass weight, back fat thickness and marbling score in Korean beef cattle. Based on the confirmation process and literature search we deduce that XP-EHH is able to uncover numerous artificial selection targets in subpopulations of domesticated animals.

Continuous detection and decoding of dexterous finger flexions with implantable myoelectric sensors.

PubMed

Baker, Justin J; Scheme, Erik; Englehart, Kevin; Hutchinson, Douglas T; Greger, Bradley

2010-08-01

A rhesus monkey was trained to perform individuated and combined finger flexions of the thumb, index, and middle finger. Nine implantable myoelectric sensors (IMES) were then surgically implanted into the finger muscles of the monkey's forearm, without any adverse effects over two years postimplantation. Using an inductive link, EMG was wirelessly recorded from the IMES as the monkey performed a finger flexion task. The EMG from the different IMES implants showed very little cross correlation. An offline parallel linear discriminant analysis (LDA) based algorithm was used to decode finger activity based on features extracted from continuously presented frames of recorded EMG. The offline parallel LDA was run on intraday sessions as well as on sessions where the algorithm was trained on one day and tested on following days. The performance of the algorithm was evaluated continuously by comparing classification output by the algorithm to the current state of the finger switches. The algorithm detected and classified seven different finger movements, including individual and combined finger flexions, and a no-movement state (chance performance = 12.5%) . When the algorithm was trained and tested on data collected the same day, the average performance was 43.8+/-3.6% n=10. When the training-testing separation period was five months, the average performance of the algorithm was 46.5+/-3.4% n=8. These results demonstrated that using EMG recorded and wirelessly transmitted by IMES offers a promising approach for providing intuitive, dexterous control of artificial limbs where human patients have sufficient, functional residual muscle following amputation.

Habitat-Specific Density and Diet of Rapidly Expanding Invasive Red Lionfish, Pterois volitans, Populations in the Northern Gulf of Mexico

PubMed Central

Dahl, Kristen A.; Patterson, William F.

2014-01-01

Invasive Indo-Pacific red lionfish, Pterois volitans, were first reported in the northern Gulf of Mexico (nGOM) in summer 2010. To examine potential impacts on native reef fish communities, lionfish density and size distributions were estimated from fall 2010 to fall 2013 with a remotely operated vehicle at natural (n = 16) and artificial (n = 22) reef sites. Lionfish (n = 934) also were sampled via spearfishing to examine effects of habitat type, season, and fish size on their diet and trophic ecology. There was an exponential increase in lionfish density at both natural and artificial reefs over the study period. By fall 2013, mean lionfish density at artificial reefs (14.7 fish 100 m−2) was two orders of magnitude higher than at natural reefs (0.49 fish 100 m−2), and already was among the highest reported in the western Atlantic. Lionfish diet was significantly different among habitats, seasons, and size classes, with smaller (<250 mm total length) fish consuming more benthic invertebrates and the diet of lionfish sampled from artificial reefs being composed predominantly of non-reef associated prey. The ontogenetic shift in lionfish feeding ecology was consistent with δ15N values of white muscle tissue that were positively related to total length. Overall, diet results indicate lionfish are generalist mesopredators in the nGOM that become more piscivorous at larger size. However, lionfish diet was much more varied at artificial reef sites where they clearly were foraging on open substrates away from reef structure. These results have important implications for tracking the lionfish invasion in the nGOM, as well as estimating potential direct and indirect impacts on native reef fish communities in this region. PMID:25170922

Habitat-specific density and diet of rapidly expanding invasive red lionfish, Pterois volitans, populations in the northern Gulf of Mexico.

PubMed

Dahl, Kristen A; Patterson, William F

2014-01-01

Invasive Indo-Pacific red lionfish, Pterois volitans, were first reported in the northern Gulf of Mexico (nGOM) in summer 2010. To examine potential impacts on native reef fish communities, lionfish density and size distributions were estimated from fall 2010 to fall 2013 with a remotely operated vehicle at natural (n = 16) and artificial (n = 22) reef sites. Lionfish (n = 934) also were sampled via spearfishing to examine effects of habitat type, season, and fish size on their diet and trophic ecology. There was an exponential increase in lionfish density at both natural and artificial reefs over the study period. By fall 2013, mean lionfish density at artificial reefs (14.7 fish 100 m(-2)) was two orders of magnitude higher than at natural reefs (0.49 fish 100 m(-2)), and already was among the highest reported in the western Atlantic. Lionfish diet was significantly different among habitats, seasons, and size classes, with smaller (<250 mm total length) fish consuming more benthic invertebrates and the diet of lionfish sampled from artificial reefs being composed predominantly of non-reef associated prey. The ontogenetic shift in lionfish feeding ecology was consistent with δ15N values of white muscle tissue that were positively related to total length. Overall, diet results indicate lionfish are generalist mesopredators in the nGOM that become more piscivorous at larger size. However, lionfish diet was much more varied at artificial reef sites where they clearly were foraging on open substrates away from reef structure. These results have important implications for tracking the lionfish invasion in the nGOM, as well as estimating potential direct and indirect impacts on native reef fish communities in this region.

[Evaluation of the cosmetic effect of orbital endoimplantation after removal the eyeball].

PubMed

Piskiniene, Raimonda

2006-01-01

The purpose of our study was to evaluate the cosmetic effect of endoimplantation after removal the eyeball. The removal of the globe creates anatomic and physiological alteration of the orbital tissue and orbital bones. A volume deficit occurs when an eye is enucleated. Deep upper lid sulcus, ptosis, lower lid laxity, and enophthalmus of the artificial eye together constitute the postenucleation socket syndrome, which creates an asymmetry of the face. The orbital prosthesis by placing it in the orbital cavity allows correcting volume deficit, so the implant with attached extraocular muscles, together with an artificial eye, creates an illusion of real eye. Forty patients were operated on in Clinic of Eye Diseases of Kaunas University of Medicine Hospital. Twenty patients underwent removal of the eye and procedure of orbital implant insertion (main group). Twenty patients had just an eyeball removal without insertion of an orbital implant (control group). There was a statistically significant difference in exophthalmometry data between main and control groups (14.20+/-2.73 vs. 10.35+/-1.23 mm, respectively; p<0.05). The motility of artificial eye laterally (4.30+/-1.66 mm), medially (3.65+/-1.23 mm), up (3.70+/-1.13 mm), and down (3.40+/-1.19 mm) in the main group was significantly better as compared to the control group (p<0.05), where motility of the artificial eye was 0.60+/-0.68 mm laterally, 0.70+/-0.92 mm medially, 0.30+/-0.66 mm up, and 0.30+/-0.47 mm down. Therefore, a much better symmetry, better movement of the artificial eye, and less severe form of postenucleation syndrome were observed in patients who underwent orbital endoimplantation after eyeball removal.

An artificial nociceptor based on a diffusive memristor.

PubMed

Yoon, Jung Ho; Wang, Zhongrui; Kim, Kyung Min; Wu, Huaqiang; Ravichandran, Vignesh; Xia, Qiangfei; Hwang, Cheol Seong; Yang, J Joshua

2018-01-29

A nociceptor is a critical and special receptor of a sensory neuron that is able to detect noxious stimulus and provide a rapid warning to the central nervous system to start the motor response in the human body and humanoid robotics. It differs from other common sensory receptors with its key features and functions, including the "no adaptation" and "sensitization" phenomena. In this study, we propose and experimentally demonstrate an artificial nociceptor based on a diffusive memristor with critical dynamics for the first time. Using this artificial nociceptor, we further built an artificial sensory alarm system to experimentally demonstrate the feasibility and simplicity of integrating such novel artificial nociceptor devices in artificial intelligence systems, such as humanoid robots.

Artificial enzymes with protein scaffolds: structural design and modification.

PubMed

Matsuo, Takashi; Hirota, Shun

2014-10-15

Recent development in biochemical experiment techniques and bioinformatics has enabled us to create a variety of artificial biocatalysts with protein scaffolds (namely 'artificial enzymes'). The construction methods of these catalysts include genetic mutation, chemical modification using synthetic molecules and/or a combination of these methods. Designed evolution strategy based on the structural information of host proteins has become more and more popular as an effective approach to construct artificial protein-based biocatalysts with desired reactivities. From the viewpoint of application of artificial enzymes for organic synthesis, recently constructed artificial enzymes mediating oxidation, reduction and C-C bond formation/cleavage are introduced in this review article. Copyright © 2014 Elsevier Ltd. All rights reserved.

Divergent skeletal muscle respiratory capacities in rats artificially selected for high and low running ability: a role for Nor1?

PubMed Central

Stephenson, Erin J.; Stepto, Nigel K.; Koch, Lauren G.; Britton, Steven L.

2012-01-01

Inactivity-related diseases are becoming a huge burden on Western society. While there is a major environmental contribution to metabolic health, the intrinsic properties that predispose or protect against particular health traits are harder to define. We used rat models of inborn high running capacity (HCR) and low running capacity (LCR) to determine inherent differences in mitochondrial volume and function, hypothesizing that HCR rats would have greater skeletal muscle respiratory capacity due to an increase in mitochondrial number. Additionally, we sought to determine if there was a link between the expression of the orphan nuclear receptor neuron-derived orphan receptor (Nor)1, a regulator of oxidative metabolism, and inherent skeletal muscle respiratory capacity. LCR rats were 28% heavier (P < 0.0001), and fasting serum insulin concentrations were 62% greater than in HCR rats (P = 0.02). In contrast, HCR rats had better glucose tolerance and reduced adiposity. In the primarily oxidative soleus muscle, maximal respiratory capacity was 21% greater in HCR rats (P = 0.001), for which the relative contribution of fat oxidation was 20% higher than in LCR rats (P = 0.02). This was associated with increased citrate synthase (CS; 33%, P = 0.009) and β-hydroxyacyl-CoA (β-HAD; 33%, P = 0.0003) activities. In the primarily glycolytic extensor digitum longus muscle, CS activity was 29% greater (P = 0.01) and β-HAD activity was 41% (P = 0.0004) greater in HCR rats compared with LCR rats. Mitochondrial DNA copy numbers were also elevated in the extensor digitum longus muscles of HCR rats (35%, P = 0.049) and in soleus muscles (44%, P = 0.16). Additionally, HCR rats had increased protein expression of individual mitochondrial respiratory complexes, CS, and uncoupling protein 3 in both muscle types (all P < 0.05). In both muscles, Nor1 protein was greater in HCR rats compared with LCR rats (P < 0.05). We propose that the differential expression of Nor1 may contribute to the differences in metabolic regulation between LCR and HCR phenotypes. PMID:22936731

Differentiation and sarcomere formation in skeletal myocytes directly prepared from human induced pluripotent stem cells using a sphere-based culture.

PubMed

Jiwlawat, Saowanee; Lynch, Eileen; Glaser, Jennifer; Smit-Oistad, Ivy; Jeffrey, Jeremy; Van Dyke, Jonathan M; Suzuki, Masatoshi

Human induced-pluripotent stem cells (iPSCs) are a promising resource for propagation of myogenic progenitors. Our group recently reported a unique protocol for the derivation of myogenic progenitors directly (without genetic modification) from human pluripotent cells using free-floating spherical culture. Here we expand our previous efforts and attempt to determine how differentiation duration, culture surface coatings, and nutrient supplements in the medium influence progenitor differentiation and formation of skeletal myotubes containing sarcomeric structures. A long differentiation period (over 6 weeks) promoted the differentiation of iPSC-derived myogenic progenitors and subsequent myotube formation. These iPSC-derived myotubes contained representative sarcomeric structures, consisting of organized myosin and actin filaments, and could spontaneously contract. We also found that a bioengineering approach using three-dimensional (3D) artificial muscle constructs could facilitate the formation of elongated myotubes. Lastly, we determined how culture surface coating matrices and different supplements would influence terminal differentiation. While both Matrigel and laminin coatings showed comparable effects on muscle differentiation, B27 serum-free supplement in the differentiation medium significantly enhanced myogenesis compared to horse serum. Our findings support the possibility to create an in vitro model of contractile sarcomeric myofibrils for disease modeling and drug screening to study neuromuscular diseases. Copyright © 2017 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Comparative contribution of trophic transfer and biotransformation on arsenobetaine bioaccumulation in two marine fish.

PubMed

Zhang, Wei; Guo, Zhiqiang; Zhou, Yanyan; Chen, Lizhao; Zhang, Li

2016-10-01

Marine fish can accumulate high arsenic (As) concentrations, with arsenobetaine (AsB) as the major species in the body. However, whether the high AsB accumulation in fish occurs mainly through trophic transfer from diet or biotransformation in the fish body remains unclear. This study investigated the trophic transfer and biotransformation of As in two marine fish (seabream Acanthopagrus schlegeli and grunt Terapon jarbua) fed artificial and clam diets for 28 d. The different diets contained different proportions of inorganic [As(III) and As(V)] and organic [methylarsenate (MMA), dimethylarsenate (DMA), and AsB] As compounds. Positive correlations were observed between the accumulated As concentrations and AsB concentrations in both fish, suggesting that AsB contributed to the accumulation of total As in marine fish. Based on the calculated total input of AsB and detected AsB concentrations in the muscle of the seabream and grunt, the ingested amounts of AsB accounted for 0.1-0.3%, 8.1-14.4% of detected AsB concentrations, respectively, in the muscle of seabream and grunt fish species, suggesting that AsB was mainly biotransformed versus trophically transferred in these marine fish. In summary, this study demonstrates that marine fish prefer to biotransform inorganic As forms into AsB, resulting in high bioaccumulation of total As. Copyright © 2016 Elsevier B.V. All rights reserved.

Generalization in Adaptation to Stable and Unstable Dynamics

PubMed Central

Kadiallah, Abdelhamid; Franklin, David W.; Burdet, Etienne

2012-01-01

Humans skillfully manipulate objects and tools despite the inherent instability. In order to succeed at these tasks, the sensorimotor control system must build an internal representation of both the force and mechanical impedance. As it is not practical to either learn or store motor commands for every possible future action, the sensorimotor control system generalizes a control strategy for a range of movements based on learning performed over a set of movements. Here, we introduce a computational model for this learning and generalization, which specifies how to learn feedforward muscle activity in a function of the state space. Specifically, by incorporating co-activation as a function of error into the feedback command, we are able to derive an algorithm from a gradient descent minimization of motion error and effort, subject to maintaining a stability margin. This algorithm can be used to learn to coordinate any of a variety of motor primitives such as force fields, muscle synergies, physical models or artificial neural networks. This model for human learning and generalization is able to adapt to both stable and unstable dynamics, and provides a controller for generating efficient adaptive motor behavior in robots. Simulation results exhibit predictions consistent with all experiments on learning of novel dynamics requiring adaptation of force and impedance, and enable us to re-examine some of the previous interpretations of experiments on generalization. PMID:23056191

Adaptive metalenses with simultaneous electrical control of focal length, astigmatism, and shift.

PubMed

She, Alan; Zhang, Shuyan; Shian, Samuel; Clarke, David R; Capasso, Federico

2018-02-01

Focal adjustment and zooming are universal features of cameras and advanced optical systems. Such tuning is usually performed longitudinally along the optical axis by mechanical or electrical control of focal length. However, the recent advent of ultrathin planar lenses based on metasurfaces (metalenses), which opens the door to future drastic miniaturization of mobile devices such as cell phones and wearable displays, mandates fundamentally different forms of tuning based on lateral motion rather than longitudinal motion. Theory shows that the strain field of a metalens substrate can be directly mapped into the outgoing optical wavefront to achieve large diffraction-limited focal length tuning and control of aberrations. We demonstrate electrically tunable large-area metalenses controlled by artificial muscles capable of simultaneously performing focal length tuning (>100%) as well as on-the-fly astigmatism and image shift corrections, which until now were only possible in electron optics. The device thickness is only 30 μm. Our results demonstrate the possibility of future optical microscopes that fully operate electronically, as well as compact optical systems that use the principles of adaptive optics to correct many orders of aberrations simultaneously.

A multiscale, model-based analysis of the multi-tissue interplay underlying blood glucose regulation in type I diabetes.

PubMed

Wadehn, Federico; Schaller, Stephan; Eissing, Thomas; Krauss, Markus; Kupfer, Lars

2016-08-01

A multiscale model for blood glucose regulation in diabetes type I patients is constructed by integrating detailed metabolic network models for fat, liver and muscle cells into a whole body physiologically-based pharmacokinetic/pharmacodynamic (pBPK/PD) model. The blood glucose regulation PBPK/PD model simulates the distribution and metabolization of glucose, insulin and glucagon on an organ and whole body level. The genome-scale metabolic networks in contrast describe intracellular reactions. The developed multiscale model is fitted to insulin, glucagon and glucose measurements of a 48h clinical trial featuring 6 subjects and is subsequently used to simulate (in silico) the influence of geneknockouts and drug-induced enzyme inhibitions on whole body blood glucose levels. Simulations of diabetes associated gene knockouts and impaired cellular glucose metabolism, resulted in elevated whole body blood-glucose levels, but also in a metabolic shift within the cell's reaction network. Such multiscale models have the potential to be employed in the exploration of novel drug-targets or to be integrated into control algorithms for artificial pancreas systems.

Nonlinear Tracking Control of a Conductive Supercoiled Polymer Actuator.

PubMed

Luong, Tuan Anh; Cho, Kyeong Ho; Song, Min Geun; Koo, Ja Choon; Choi, Hyouk Ryeol; Moon, Hyungpil

2018-04-01

Artificial muscle actuators made from commercial nylon fishing lines have been recently introduced and shown as a new type of actuator with high performance. However, the actuators also exhibit significant nonlinearities, which make them difficult to control, especially in precise trajectory-tracking applications. In this article, we present a nonlinear mathematical model of a conductive supercoiled polymer (SCP) actuator driven by Joule heating for model-based feedback controls. Our efforts include modeling of the hysteresis behavior of the actuator. Based on nonlinear modeling, we design a sliding mode controller for SCP actuator-driven manipulators. The system with proposed control law is proven to be asymptotically stable using the Lyapunov theory. The control performance of the proposed method is evaluated experimentally and compared with that of a proportional-integral-derivative (PID) controller through one-degree-of-freedom SCP actuator-driven manipulators. Experimental results show that the proposed controller's performance is superior to that of a PID controller, such as the tracking errors are nearly 10 times smaller compared with those of a PID controller, and it is more robust to external disturbances such as sensor noise and actuator modeling error.

Thermochromic Artificial Nacre Based on Montmorillonite.

PubMed

Peng, Jingsong; Cheng, Yiren; Tomsia, Antoni P; Jiang, Lei; Cheng, Qunfeng

2017-07-26

Nacre-inspired nanocomposites have attracted a great deal of attention in recent years because of their special mechanical properties and universality of the underlying principles of materials engineering. The ability to respond to external stimuli will augment the high toughness and high strength of artificial nacre-like composites and open new technological horizons for these materials. Herein, we fabricated robust artificial nacre based on montmorillonite (MMT) that combines robustness with reversible thermochromism. Our artificial nacre shows great potential in various fields such as aerospace and sensors and opens an avenue to fabricate artificial nacre responsive to other external stimuli in the future.

Intrinsic aerobic capacity correlates with greater inherent mitochondrial oxidative and H2O2 emission capacities without major shifts in myosin heavy chain isoform

PubMed Central

Seifert, Erin L.; Bastianelli, Mark; Aguer, Céline; Moffat, Cynthia; Estey, Carmen; Koch, Lauren G.; Britton, Steven L.

2012-01-01

Exercise capacity and performance strongly associate with metabolic and biophysical characteristics of skeletal muscle, factors that also relate to overall disease risk. Despite its importance, the exact mechanistic features that connect aerobic metabolism with health status are unknown. To explore this, we applied artificial selection of rats for intrinsic (i.e., untrained) aerobic treadmill running to generate strains of low- and high-capacity runners (LCR and HCR, respectively), subsequently shown to diverge for disease risk. Concurrent breeding of LCR and HCR per generation allows the lines to serve as reciprocal controls for unknown environmental changes. Here we provide the first direct evidence in mitochondria isolated from skeletal muscle that intrinsic mitochondrial capacity is higher in HCR rats. Maximal phosphorylating respiration was ∼40% greater in HCR mitochondria, independent of substrate and without altered proton leak or major changes in protein levels or muscle fiber type, consistent with altered control of phosphorylating respiration. Unexpectedly, H2O2 emission was ∼20% higher in HCR mitochondria, due to greater reduction of more harmful reactive oxygen species to H2O2; indeed, oxidative modification of mitochondrial proteins was lower. When the higher mitochondrial yield was considered, phosphorylating respiration and H2O2 emission were 70–80% greater in HCR muscle. Greater capacity of HCR muscle for work and H2O2 signaling may result in enhanced and more immediate cellular repair, possibly explaining lowered disease risks. PMID:22995392

Human skeletal muscle responses to spaceflight and possible countermeasures

NASA Technical Reports Server (NTRS)

Gollnick, Philip D.; Edgerton, V. Reggie; Saltin, Bengt

1990-01-01

The current status of knowledge concerning the effects of unweighting skeletal muscle is summarized. The results of both ground-based and space-based animal studies are reviewed which show that there is rapid loss in muscle mass, primarily in slow-twitch muscle, of the rat during unweighting of muscle. There is also a shift in the myosin isoforms with muscles such that slow-twitch muscles take on many of the characteristics of fast-twitch muscles. Ground-based studies in human suggest that programs of electrical stimulation can be developed to simulate normal muscular contractions. Attempts to develop countermeasures to the adverse effects of space travel on muscular functions in humans have not been successful to date.

Artificial Intelligence-Based Student Learning Evaluation: A Concept Map-Based Approach for Analyzing a Student's Understanding of a Topic

ERIC Educational Resources Information Center

Jain, G. Panka; Gurupur, Varadraj P.; Schroeder, Jennifer L.; Faulkenberry, Eileen D.

2014-01-01

In this paper, we describe a tool coined as artificial intelligence-based student learning evaluation tool (AISLE). The main purpose of this tool is to improve the use of artificial intelligence techniques in evaluating a student's understanding of a particular topic of study using concept maps. Here, we calculate the probability distribution of…

Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production

DTIC Science & Technology

2017-06-30

AFRL-AFOSR-JP-TR-2017-0054 Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production Mamoru Nango NAGOYA INSTITUTE OF TECHNOLOGY...for Solar Fuel Production 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4015 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Mamoru Nango 5d...density immobilization of the photoreactants in the nanocavity inside PGP. The maximum production efficiency of formic acid inside the nanocavity was

Modular Extended-Stay HyperGravity Facility Design Concept: An Artificial-Gravity Space-Settlement Ground Analogue

NASA Technical Reports Server (NTRS)

Dorais, Gregory A.

2015-01-01

This document defines the design concept for a ground-based, extended-stay hypergravity facility as a precursor for space-based artificial-gravity facilities that extend the permanent presence of both human and non-human life beyond Earth in artificial-gravity settlements. Since the Earth's current human population is stressing the environment and the resources off-Earth are relatively unlimited, by as soon as 2040 more than one thousand people could be living in Earthorbiting artificial-gravity habitats. Eventually, the majority of humanity may live in artificialgravity habitats throughout this solar system as well as others, but little is known about the longterm (multi-generational) effects of artificial-gravity habitats on people, animals, and plants. In order to extend life permanently beyond Earth, it would be useful to create an orbiting space facility that generates 1g as well as other gravity levels to rigorously address the numerous challenges of such an endeavor. Before doing so, developing a ground-based artificial-gravity facility is a reasonable next step. Just as the International Space Station is a microgravity research facility, at a small fraction of the cost and risk a ground-based artificial-gravity facility can begin to address a wide-variety of the artificial-gravity life-science questions and engineering challenges requiring long-term research to enable people, animals, and plants to live off-Earth indefinitely.

Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites.

PubMed

Kim, Hojin; Zhu, Bohan; Chen, Huiying; Adetiba, Oluwatomiyin; Agrawal, Aditya; Ajayan, Pulickel; Jacot, Jeffrey G; Verduzco, Rafael

2016-02-06

LCEs are shape-responsive materials with fully reversible shape change and potential applications in medicine, tissue engineering, artificial muscles, and as soft robots. Here, we demonstrate the preparation of shape-responsive liquid crystal elastomers (LCEs) and LCE nanocomposites along with characterization of their shape-responsiveness, mechanical properties, and microstructure. Two types of LCEs - polysiloxane-based and epoxy-based - are synthesized, aligned, and characterized. Polysiloxane-based LCEs are prepared through two crosslinking steps, the second under an applied load, resulting in monodomain LCEs. Polysiloxane LCE nanocomposites are prepared through the addition of conductive carbon black nanoparticles, both throughout the bulk of the LCE and to the LCE surface. Epoxy-based LCEs are prepared through a reversible esterification reaction. Epoxy-based LCEs are aligned through the application of a uniaxial load at elevated (160 °C) temperatures. Aligned LCEs and LCE nanocomposites are characterized with respect to reversible strain, mechanical stiffness, and liquid crystal ordering using a combination of imaging, two-dimensional X-ray diffraction measurements, differential scanning calorimetry, and dynamic mechanical analysis. LCEs and LCE nanocomposites can be stimulated with heat and/or electrical potential to controllably generate strains in cell culture media, and we demonstrate the application of LCEs as shape-responsive substrates for cell culture using a custom-made apparatus.

The Gravity of the Situation. Chapter 1

NASA Technical Reports Server (NTRS)

Paloski, William; Clement, Gilles; Bukley, Angie; Paloski, William

2006-01-01

Prolonged exposure in humans to a microgravity environment can lead to significant loss of bone and muscle mass, cardiovascular and sensory-motor deconditioning, and hormonal changes. These adaptive changes to weightlessness present a formidable obstacle to human exploration of space, particularly for missions requiring travel times of several months or more, such as on a trip to Mars. Countermeasures that address each of these body systems separately show only limited success. One possible remedy for this situation is artificial gravity, because it tackles all these systems across the board.

Walking in a rotating space station, an electromyographic and kinematic study

NASA Technical Reports Server (NTRS)

Harris, R. L.

1975-01-01

Biomechanics were studied of locomotion in a rotating environment like that of a space station at various gravity levels. Comparisons were made of the walking gait patterns and the amplitudes of various leg muscle electrical outputs at different gravity levels. The results of these tests are applicable to planning future space missions by providing a part of the information that will be needed to determine the type of vehicle and the gravity level to be provided for the astronauts if it is decided that artificial gravity is to be utilized.

Ionic electroactive polymer artificial muscles in space applications

PubMed Central

Punning, Andres; Kim, Kwang J.; Palmre, Viljar; Vidal, Frédéric; Plesse, Cédric; Festin, Nicolas; Maziz, Ali; Asaka, Kinji; Sugino, Takushi; Alici, Gursel; Spinks, Geoff; Wallace, Gordon; Must, Indrek; Põldsalu, Inga; Vunder, Veiko; Temmer, Rauno; Kruusamäe, Karl; Torop, Janno; Kaasik, Friedrich; Rinne, Pille; Johanson, Urmas; Peikolainen, Anna-Liisa; Tamm, Tarmo; Aabloo, Alvo

2014-01-01

A large-scale effort was carried out to test the performance of seven types of ionic electroactive polymer (IEAP) actuators in space-hazardous environmental factors in laboratory conditions. The results substantiate that the IEAP materials are tolerant to long-term freezing and vacuum environments as well as ionizing Gamma-, X-ray, and UV radiation at the levels corresponding to low Earth orbit (LEO) conditions. The main aim of this material behaviour investigation is to understand and predict device service time for prolonged exposure to space environment. PMID:25372857

Control of an optimal finger exoskeleton based on continuous joint angle estimation from EMG signals.

PubMed

Ngeo, Jimson; Tamei, Tomoya; Shibata, Tomohiro; Orlando, M F Felix; Behera, Laxmidhar; Saxena, Anupam; Dutta, Ashish

2013-01-01

Patients suffering from loss of hand functions caused by stroke and other spinal cord injuries have driven a surge in the development of wearable assistive devices in recent years. In this paper, we present a system made up of a low-profile, optimally designed finger exoskeleton continuously controlled by a user's surface electromyographic (sEMG) signals. The mechanical design is based on an optimal four-bar linkage that can model the finger's irregular trajectory due to the finger's varying lengths and changing instantaneous center. The desired joint angle positions are given by the predictive output of an artificial neural network with an EMG-to-Muscle Activation model that parameterizes electromechanical delay (EMD). After confirming good prediction accuracy of multiple finger joint angles we evaluated an index finger exoskeleton by obtaining a subject's EMG signals from the left forearm and using the signal to actuate a finger on the right hand with the exoskeleton. Our results show that our sEMG-based control strategy worked well in controlling the exoskeleton, obtaining the intended positions of the device, and that the subject felt the appropriate motion support from the device.

Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor

PubMed Central

Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei

2014-01-01

A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process. PMID:24389750

Quality and biochemical properties of artificially hibernated crucian carp for waterless preservation.

PubMed

Mi, Hongbo; Qian, Chunlu; Mao, Linchun

2012-12-01

The aim of this study was to explore the artificial hibernation of crucian carp for waterless preservation and to characterize the quality and biochemical properties during and after the hibernation. Anesthetized crucian carp using eugenol were stored at 8 °C with 90 % oxygen and 95-100 % relative humidity for 38 h and then transferred to fresh water to recover. Liquid loss and cooking loss had no significant changes (p > 0.05). The total volatile basic nitrogen content and 2-thiobarbituric acid value in hibernated fish were significantly higher (p < 0.05) than fresh and recovered groups. Serum cortisol, glutamic-oxaloacetic transaminase (GOT), alkaline phosphatase (AKP), and acid phosphatase (ACP) activities significantly increased (p < 0.05) during hibernation, while glutamic-pyruvic transaminase (GPT) had no significant change (p > 0.05). Both ACP and AKP activities decreased upon the fish recovered, but only the ACP activity returned to normal. However, there were increased serum glucose concentration, GOT and GPT activities in recovered fish. On the basis of these findings, it can be concluded that the artificially hibernated life of crucian carp was 38 h by the combination of anaesthetizing and low temperature. The muscle quality would not be influenced, and most of the stress responses would disappear after hibernated fish recovered.

CARS and SHG microscopy of artificial bioengineered tissues

NASA Astrophysics Data System (ADS)

Enejder, Annika; Brackmann, Christian; Dahlberg, Jan-Olof; Vrana, Engin; Gatenholm, Paul

2010-02-01

Major efforts are presently made to develop artificial replacement tissues with optimal architectural and material characteristics, mimicking those of their natural correspondents. Encouraged by the readiness with which cellulose fibers woven by the bacteria Acetobacter xylinum can be formed into organ-like macroscopic shapes and with different microscopic textures, it emerges as an interesting material within tissue engineering. We have developed a protocol employing simultaneous CARS and SHG microscopy for monitoring the cellulose network characteristics and its impact on the integration of smooth muscle cells (SMCs) for functionalized artificial tissues. CARS and SHG overlay images of the cells and the cellulose fibers reveal an immediate interaction irrespective of scaffold morphology and that the SMCs attach to the cellulose fibers already during the first cultivation day without cell-adhesive coatings. During the subsequent 28 days, SMCs were found to readily proliferate and differentiate on the cellulose scaffold without the need for exogenous growth factors. However, the efficiency with which this occurred depended on the topography of the cellulose constructs, benefited by porous and less compact matrices. This brings forward the need for in-depth studies on how the microstructure of tissue scaffolds influences and can be optimized for native cell integration and proliferation, studies where the benefits of multi-modal non-linear microscopy can be fully exploited.

Biologically inspired robotic inspectors: the engineering reality and future outlook (Keynote address)

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph

2005-04-01

Human errors have long been recognized as a major factor in the reliability of nondestructive evaluation results. To minimize such errors, there is an increasing reliance on automatic inspection tools that allow faster and consistent tests. Crawlers and various manipulation devices are commonly used to perform variety of inspection procedures that include C-scan with contour following capability to rapidly inspect complex structures. The emergence of robots has been the result of the need to deal with parts that are too complex to handle by a simple automatic system. Economical factors are continuing to hamper the wide use of robotics for inspection applications however technology advances are increasingly changing this paradigm. Autonomous robots, which may look like human, can potentially address the need to inspect structures with configuration that are not predetermined. The operation of such robots that mimic biology may take place at harsh or hazardous environments that are too dangerous for human presence. Biomimetic technologies such as artificial intelligence, artificial muscles, artificial vision and numerous others are increasingly becoming common engineering tools. Inspired by science fiction, making biomimetic robots is increasingly becoming an engineering reality and in this paper the state-of-the-art will be reviewed and the outlook for the future will be discussed.

[Analysis of surgical treatment with pectoralis major muscle flap for deep sternal infection after cardiac surgery: a case series of 189 patients].

PubMed

Liu, Dong; Wang, Wenzhang; Cai, Aibing; Han, Zhiyi; Li, Xiyuan; Ma, Jiagui

2015-03-01

To analyze and summarize the clinical features and experience in surgical treatment of deep sternal infection (DSWI). This was a retrospective study. From January 2008 to December 2013, 189 patients with secondary DSWI after cardiac surgery underwent the pectoralis major muscle flap transposition in our department. There were 116 male and 73 female patients. The mean age was (54 ± 21) years, the body mass index was (26. 1 ± 1. 3) kg/m2. The incidence of postoperation DSWI were after isolated coronary artery bypass grafting (CABG) in 93 patients, after other heart surgery plus CABG in 13 patients, after valve surgery in 47 patients, after thoracic aortic surgery in 16 patients, after congenital heart disease in 18 patients, and after cardiac injury in 2 patients. Clean patients' wound and extract secretions, clear the infection thoroughly by surgery and select antibiotics based on susceptibility results, and then repair the wound with appropriate muscle flap, place drain tube with negative pressure. Of all the 189 patients, 184 used isolate pectoralis, 1 used isolate rectus, and 4 used pectoralis plus rectus. The operative wounds of 179 patients were primary healing (94. 7%). Hospital discharge was postponed by 1 week for 7 patients, due to subcutaneous wound infection. Subcutaneous wound infection occurred again in 8 patients 1 week after hospital discharge, and their wounds healed after wound dressing. Nine patients (4. 7%) did not recover, due to residue of the sequestrum and costal chondritis, whom were later cured by undergoing a second treatment of debridement and pectoralis major muscle flap transposition. Eight patients died, in which 2 died of respiratory failure, 2 died of bacterial endocarditis with septicemia, 2 died of renal failure, 1 died of intraoperative bleeding leading to brain death and the 1 died of heart failure. The mortality rate was 4. 2% . The average length of postoperative hospital stay was (14 ± 5) days. The longest postoperative follow-up period was 40 months, the median time was 26 months, the follow-up rate was 83. 9% . Totally 179 patients were no-reinfected, 2 patients were reinfected because of artificial vascular rejection. To perform surgical debridement and then reconstruct the sternal defect with pectoralis major muscle flap actively for the patient is an effective measure to improve patient's survival rate.

The effect of intramuscular fat on skeletal muscle mechanics: implications for the elderly and obese

PubMed Central

Rahemi, Hadi; Nigam, Nilima; Wakeling, James M.

2015-01-01

Skeletal muscle accumulates intramuscular fat through age and obesity. Muscle quality, a measure of muscle strength per unit size, decreases in these conditions. It is not clear how fat influences this loss in performance. Changes to structural parameters (e.g. fibre pennation and connective tissue properties) affect the muscle quality. This study investigated the mechanisms that lead to deterioration in muscle performance due to changes in intramuscular fat, pennation and aponeurosis stiffness. A finite-element model of the human gastrocnemius was developed as a fibre-reinforced composite biomaterial containing contractile fibres within the base material. The base-material properties were modified to include intramuscular fat in five different ways. All these models with fat generated lower fibre stress and muscle quality than their lean counterparts. This effect is due to the higher stiffness of the tissue in the fatty models. The fibre deformations influence their interactions with the aponeuroses, and these change with fatty inclusions. Muscles with more compliant aponeuroses generated lower forces. The muscle quality was further reduced for muscles with lower pennation. This study shows that whole-muscle force is dependent on its base-material properties and changes to the base material due to fatty inclusions result in reductions to force and muscle quality. PMID:26156300

Environmental Stability of Plasmonic Biosensors Based on Natural versus Artificial Antibody.

PubMed

Luan, Jingyi; Xu, Ting; Cashin, John; Morrissey, Jeremiah J; Kharasch, Evan D; Singamaneni, Srikanth

2018-06-13

Plasmonic biosensors based on the refractive index sensitivity of localized surface plasmon resonance (LSPR) are considered to be highly promising for on-chip and point-of-care biodiagnostics. However, most of the current plasmonic biosensors employ natural antibodies as biorecognition elements, which can easily lose their biorecognition ability upon exposure to environmental stressors (e.g., temperature and humidity). Plasmonic biosensors relying on molecular imprints as recognition elements (artificial antibodies) are hypothesized to be an attractive alternative for applications in resource-limited settings due to their excellent thermal, chemical, and environmental stability. In this work, we provide a comprehensive comparison of the stability of plasmonic biosensors based on natural and artificial antibodies. Although the natural antibody-based plasmonic biosensors exhibit superior sensitivity, their stability (temporal, thermal, and chemical) was found to be vastly inferior to those based on artificial antibodies. Our results convincingly demonstrate that these novel classes of artificial antibody-based plasmonic biosensors are highly attractive for point-of-care and resource-limited conditions where tight control over transport, storage, and handling conditions is not possible.

Analogue spin-orbit torque device for artificial-neural-network-based associative memory operation

NASA Astrophysics Data System (ADS)

Borders, William A.; Akima, Hisanao; Fukami, Shunsuke; Moriya, Satoshi; Kurihara, Shouta; Horio, Yoshihiko; Sato, Shigeo; Ohno, Hideo

2017-01-01

We demonstrate associative memory operations reminiscent of the brain using nonvolatile spintronics devices. Antiferromagnet-ferromagnet bilayer-based Hall devices, which show analogue-like spin-orbit torque switching under zero magnetic fields and behave as artificial synapses, are used. An artificial neural network is used to associate memorized patterns from their noisy versions. We develop a network consisting of a field-programmable gate array and 36 spin-orbit torque devices. An effect of learning on associative memory operations is successfully confirmed for several 3 × 3-block patterns. A discussion on the present approach for realizing spintronics-based artificial intelligence is given.

Beta-Adrenergic Receptor Population is Up-Regulated in Chicken Skeletal Muscle Cells Treated with Forskolin

NASA Technical Reports Server (NTRS)

Bridge, K. Y.; Young, R. B.; Vaughn, J. R.

1998-01-01

Skeletal muscle hypertrophy is promoted by in vivo administration of beta-adrenergic receptor (betaAR) agonists. These compounds presumably exert their physiological action through the betaAR, and alterations in the population of betaAR could potentially change the ability of the cell to respond to the betaAR agonists. Since the intracellular chemical signal generated by the betaAR is cyclic AMP (cAMP), experiments were initiated in primary chicken muscle cell cultures to determine if artificial elevation of intracellular cAMP by treatment with forskolin would alter the population of functional betaAR expressed on the surface of muscle cells. Chicken skeletal muscle cells after 7 days in culture were employed for the experiments because muscle cells have attained a steady state with respect to muscle protein metabolism at this stage. Cells were treated with 0-10 microM forskolin for a total of three days. At the end of the 1, 2, and 3 day treatment intervals, the concentration of cAMP and the betaAR population were measured. Receptor population was measured in intact muscle cell cultures as the difference between total binding of [H-3]CGP-12177 and non-specific binding of [H-3]CGP-12177 in the presence of 1 microM propranolol. Intracellular cAMP concentration was measured by radioimmunoassay. The concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in betaAR population, with a maximum increase of approximately 50% at 10 microM. This increase in PAR population was apparent after only 1 day of treatment, and the pattern of increase was maintained for all 3 days of the treatment period. Thus, increasing the intracellular concentration of cAMP leads to up-regulation of betaAR population. The effect of forskolin on the quantity and apparent synthesis rate of the heavy chain of myosin (mhc) were also investigated. A maximum increase of 50% in the quantity of mhc was observed at 0.2 microM forskolin, but higher concentrations of forskolin reduced the quantity of mhc back to control levels.

Case-Based Planning: An Integrated Theory of Planning, Learning and Memory

DTIC Science & Technology

1986-10-01

rtvoeoo oldo II nocomtmry and Idonltly by block numbor) planning Case-based reasoning learning Artificial Intelligence 20. ABSTRACT (Conllnum...Computational Model of Analogical Prob- lem Solving, Proceedings of the Seventh International Joint Conference on Artificial Intelligence ...Understanding and Generalizing Plans., Proceedings of the Eight Interna- tional Joint Conference on Artificial Intelligence , IJCAI, Karlsrhue, Germany

Human Research Program Human Health Countermeasures Element: Evidence Report - Artificial Gravity

NASA Technical Reports Server (NTRS)

Clement, Gilles

2015-01-01

The most serious risks of long-duration flight involve radiation, behavioral stresses, and physiological deconditioning. Artificial gravity (AG), by substituting for the missing gravitational cues and loading in space, has the potential to mitigate the last of these risks by preventing the adaptive responses from occurring. The rotation of a Mars-bound spacecraft or an embarked human centrifuge offers significant promise as an effective, efficient multi-system countermeasure against the physiological deconditioning associated with prolonged weightlessness. Virtually all of the identified risks associated with bone loss, muscle weakening, cardiovascular deconditioning, and sensorimotor disturbances might be alleviated by the appropriate application of AG. However, experience with AG in space has been limited and a human-rated centrifuge is currently not available on board the ISS. A complete R&D program aimed at determining the requirements for gravity level, gravity gradient, rotation rate, frequency, and duration of AG exposure is warranted before making a decision for implementing AG in a human spacecraft.

Effect of 7-days dry immersion in combination with mechanical stimulation of foot support zones upon resistance to fatigue of knee extensors and flexors

NASA Astrophysics Data System (ADS)

Netreba, A. I.; Khusnutdiniva, D. R.; Vinogradova, O. L.; Kozlovskaya, I. B.

2005-08-01

The aim of investigation was to reveal the effect of supportlessness in combination with artificial stimulation of foot support zones on fatigue resistance of knee extensors and flexors in static and rhythmic tests. 10 volunteers were exposed to 7 days dry immersion (DI). 4 of them were subjected to mechanical stimulation of foot support zones. 7-day DI did not evoke any changes in fatigue resistance during rhythmic contractions of knee extensors and flexors in both groups. Static test revealed significant decrease of fatigue resistance of both knee flexors and extensors. In the group with stimulation of support zones unfavorable effects of immersion were minimized for knee extensors but not for flexors. Thus support withdrawal is associated with a decrease of fatigue resistance for both knee flexors and extensors only under conditions of static tension. Artificial stimulation of support zones of the foot selectively affects the posture muscles.

Stress measurements of planar dielectric elastomer actuators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osmani, Bekim; Aeby, Elise A.; Müller, Bert

Dielectric elastomer actuator (DEA) micro- and nano-structures are referred to artificial muscles because of their specific continuous power and adequate time response. The bending measurement of an asymmetric, planar DEA is described. The asymmetric cantilevers consist of 1 or 5 μm-thin DEAs deposited on polyethylene naphthalate (PEN) substrates 16, 25, 38, or 50 μm thick. The application of a voltage to the DEA electrodes generates an electrostatic pressure in the sandwiched silicone elastomer layer, which causes the underlying PEN substrate to bend. Optical beam deflection enables the detection of the bending angle vs. applied voltage. Bending radii as large asmore » 850 m were reproducibly detected. DEA tests with electric fields of up to 80 V/μm showed limitations in electrode’s conductivity and structure failures. The actuation measurement is essential for the quantitative characterization of nanometer-thin, low-voltage, single- and multi-layer DEAs, as foreseen for artificial sphincters to efficiently treat severe urinary and fecal incontinence.« less

[Research on the Kosmos biosatellites].

PubMed

Il'in, E A

1984-01-01

In the last decade the USSR has launched six biosatellites of the Cosmos series. The duration of the first flight was 6 days and of the five subsequent flights 18 to 21 days. The major goals of the flight studies were: investigation of adaptation of living systems to weightlessness, identification of the modifying effect of weightlessness on radiosensitivity, and detection of the biological effect of artificial gravity. The examinations were performed on 37 biological species, with most of them on rats. The exposure to weightlessness gave rise to moderate stress reactions and specific changes, particularly in the musculo-skeletal system (muscle atrophy, reduced bone strength, etc). Artificial gravity of 1 g generated inflight helped maintain the normal function of most physiological systems. The exposure of mammals (rats) to 137Ce irradiation did not reveal a modifying effect of weightlessness on radiation sickness. Distinct manifestations of the effects of weightlessness on intracellular processes were not observed. Dissimilar results were obtained with respect to the growth and development of living organisms in weightlessness.

A Large Radius Human Centrifuge: The Human Hypergravity Havitat

NASA Astrophysics Data System (ADS)

van Loon, J. J. W. A.

2008-06-01

Life on Earth has developed at unit gravity, 9.81 m/s2, but how would plants and animals have evolved on a larger planet, i.e. larger than Earth? We are able to address this question simply by studies using centrifuges. In the past decades numerous experiments have been performed on cells, plants and animals grown for longer durations, even multi generations, under hypergravity conditions. Based on these studies we have gained interesting insights in the physiological process of these systems when exposed to artificial gravity. Animals and plants adapt themselves to this new high-g environment. Information of adaptation to hyper-g in mammals is interesting, or maybe even proof vital, for future human space flight programs especially in light of long duration missions to Moon and Mars. We know from long duration animal studies that numerous physiological processes and structures like muscles, bones, neuro-vestibular, or the cardiovascular system are affected. However, humans have never been exposed to a hyper-g environment for long durations. Human studies are mostly in the order of hours at most. Current work on human centrifuges is all focused on short arm systems to apply artificial gravity in long duration space missions. In this paper we want to address the possible usefulness of a large radius human centrifuge on Earth, or even on Moon or Mars, for both basic research and possible applications. In such a centrifuge a group of humans may be exposed to hypergravity for, in principle, an unlimited period of time.

Modeling and Simulation of Viscous Electro-Active Polymers

PubMed Central

Vogel, Franziska; Göktepe, Serdar; Steinmann, Paul; Kuhl, Ellen

2014-01-01

Electro-active materials are capable of undergoing large deformation when stimulated by an electric field. They can be divided into electronic and ionic electro-active polymers (EAPs) depending on their actuation mechanism based on their composition. We consider electronic EAPs, for which attractive Coulomb forces or local re-orientation of polar groups cause a bulk deformation. Many of these materials exhibit pronounced visco-elastic behavior. Here we show the development and implementation of a constitutive model, which captures the influence of the electric field on the visco-elastic response within a geometrically non-linear finite element framework. The electric field affects not only the equilibrium part of the strain energy function, but also the viscous part. To adopt the familiar additive split of the strain from the small strain setting, we formulate the governing equations in the logarithmic strain space and additively decompose the logarithmic strain into elastic and viscous parts. We show that the incorporation of the electric field in the viscous response significantly alters the relaxation and hysteresis behavior of the model. Our parametric study demonstrates that the model is sensitive to the choice of the electro-viscous coupling parameters. We simulate several actuator structures to illustrate the performance of the method in typical relaxation and creep scenarios. Our model could serve as a design tool for micro-electro-mechanical systems, microfluidic devices, and stimuli-responsive gels such as artificial skin, tactile displays, or artificial muscle. PMID:25267881

Cooperative Knowledge Bases.

DTIC Science & Technology

1988-02-01

intellegent knowledge bases. The present state of our system for concurrent evaluation of a knowledge base of logic clauses using static allocation...de Kleer, J., An assumption-based TMS, Artificial Intelligence, Vol. 28, No. 2, 1986. [Doyle 79) Doyle, J. A truth maintenance system, Artificial

Adolescent muscle dysmorphia and family-based treatment: a case report.

PubMed

Murray, Stuart B; Griffiths, Scott

2015-04-01

A growing body of evidence suggests that the prevalence of male body dissatisfaction and muscle dysmorphia is rising. To date, however, there is no published evidence on the efficacy of treatments for muscle dysmorphia. We present the case of a 15-year-old boy who met full diagnostic criteria for muscle dysmorphia, whose symptoms were treated into remission with eating disorder-focused, family-based treatment. The age of this patient fell within the time period in which symptoms of muscle dysmorphia are most likely to develop and this case represents the first published case report of family-based treatment for muscle dysmorphia in this age group. Thus, this case report has important implications for clinicians considering treatment options for presentations of muscle dysmorphia when first presenting in adolescence. Implications for the development of treatment guidelines for muscle dysmorphia and for the diagnostic debate surrounding muscle dysmorphia are also discussed. © The Author(s) 2014.

Towards the application of one-dimensional sonomyography for powered upper-limb prosthetic control using machine learning models.

PubMed

Guo, Jing-Yi; Zheng, Yong-Ping; Xie, Hong-Bo; Koo, Terry K

2013-02-01

The inherent properties of surface electromyography limit its potential for multi-degrees of freedom control. Our previous studies demonstrated that wrist angle could be predicted by muscle thickness measured from B-mode ultrasound, and hence, it could be an alternative signal for prosthetic control. However, an ultrasound imaging machine is too bulky and expensive. We aim to utilize a portable A-mode ultrasound system to examine the feasibility of using one-dimensional sonomyography (i.e. muscle thickness signals detected by A-mode ultrasound) to predict wrist angle with three different machine learning models - (1) support vector machine (SVM), (2) radial basis function artificial neural network (RBF ANN), and (3) back-propagation artificial neural network (BP ANN). Feasibility study using nine healthy subjects. Each subject performed wrist extension guided at 15, 22.5, and 30 cycles/minute, respectively. Data obtained from 22.5 cycles/minute trials was used to train the models and the remaining trials were used for cross-validation. Prediction accuracy was quantified by relative root mean square error (RMSE) and correlation coefficients (CC). Excellent prediction was noted using SVM (RMSE = 13%, CC = 0.975), which outperformed the other methods. It appears that one-dimensional sonomyography could be an alternative signal for prosthetic control. Clinical relevance Surface electromyography has inherent limitations that prohibit its full functional use for prosthetic control. Research that explores alternative signals to improve prosthetic control (such as the one-dimensional sonomyography signals evaluated in this study) may revolutionize powered prosthesis design and ultimately benefit amputee patients.

Challenges to the Transition of IPMC Artificial Muscle Actuators to Practical Application

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Leary, Sean; Oguro, Keisuke; Tadokoro, Satoshi; Harrison, Joycelyn; Smith, Joseph; Su, Ji

1999-01-01

Ion-exchange membrane metallic composites (IPMC), which were first reported in 1992, are one of the electroactive materials (EAP) with potential applications as artificial muscle actuators. The recent introduction of perfluorocarboxylate-gold composite with tetra-n-butylammonium and Lithium cations instead of sodium made the most significant improvement of the material electroactivity. Under less than 3 volts, IPMC with the new constituents is capable of bending beyond a complete loop. Taking into account the fact that IMPC materials do not induce a significant force, the authors are extensively seeking applications for these bending EAP. Some of the applications that were demonstrated include dust-wiper, catheter guide, miniature motor, robotic-gripper, micro-manipulator, etc. Generally, space applications are the most demanding in terms of operating conditions, robustness and durability, and the co-authors of this paper are jointly addressing the associated challenges. Specifically, a dust-wiper is being developed for the Nanorover's infrared camera window of the MUSES-CN mission. This joint NASA and the Japanese space agency mission, is scheduled to be launch from Kagoshima, Japan, in January 2002, to explore the surface of a small near-Earth asteroid. Several issues that are critical to the operation of IPMC are addressed including the operation in vacuum, low temperatures, and the effect of the electromechanical characteristic of the IPMC on its actuation capability. Highly efficient IPMC materials, mechanical modeling, unique elements and protective coating were introduced by the authors and are making a high probability the success of the IPMC actuated dust-wiper.

[Thermodynamic principles and physiologic criteria for the use of heat engines to drive the ventricles of an artificial heart].

PubMed

Kiselev, Iu M; Mordashev, V M; Osipov, A P; Shumakov, V I

1990-01-01

The authors review the thermodynamic bases and physiological limitations of the applicability of thermal engines for driving artificial heart ventricles. Show that the thermodynamic characteristics of Stirling and Brighton cycles do not make it possible to effectively use cycle-based engines in the artificial heart. A steam engine operating in accordance with the Rankine cycle may be regarded as an optimum type engine for that purpose. Demonstrate that according to the rules of physiology, use should be made of a separate driving of artificial heart ventricles by two independently operating steam engines. Provide the characteristics of the Soviet artificial heart "MIKRON" acceptable for implantation into the orthotopic position.

Continuous and simultaneous estimation of finger kinematics using inputs from an EMG-to-muscle activation model.

PubMed

Ngeo, Jimson G; Tamei, Tomoya; Shibata, Tomohiro

2014-08-14

Surface electromyography (EMG) signals are often used in many robot and rehabilitation applications because these reflect motor intentions of users very well. However, very few studies have focused on the accurate and proportional control of the human hand using EMG signals. Many have focused on discrete gesture classification and some have encountered inherent problems such as electro-mechanical delays (EMD). Here, we present a new method for estimating simultaneous and multiple finger kinematics from multi-channel surface EMG signals. In this study, surface EMG signals from the forearm and finger kinematic data were extracted from ten able-bodied subjects while they were tasked to do individual and simultaneous multiple finger flexion and extension movements in free space. Instead of using traditional time-domain features of EMG, an EMG-to-Muscle Activation model that parameterizes EMD was used and shown to give better estimation performance. A fast feed forward artificial neural network (ANN) and a nonparametric Gaussian Process (GP) regressor were both used and evaluated to estimate complex finger kinematics, with the latter rarely used in the other related literature. The estimation accuracies, in terms of mean correlation coefficient, were 0.85 ± 0.07, 0.78 ± 0.06 and 0.73 ± 0.04 for the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and the distal interphalangeal (DIP) finger joint DOFs, respectively. The mean root-mean-square error in each individual DOF ranged from 5 to 15%. We show that estimation improved using the proposed muscle activation inputs compared to other features, and that using GP regression gave better estimation results when using fewer training samples. The proposed method provides a viable means of capturing the general trend of finger movements and shows a good way of estimating finger joint kinematics using a muscle activation model that parameterizes EMD. The results from this study demonstrates a potential control strategy based on EMG that can be applied for simultaneous and continuous control of multiple DOF(s) devices such as robotic hand/finger prostheses or exoskeletons.

A Physiologically Based, Multi-Scale Model of Skeletal Muscle Structure and Function

PubMed Central

Röhrle, O.; Davidson, J. B.; Pullan, A. J.

2012-01-01

Models of skeletal muscle can be classified as phenomenological or biophysical. Phenomenological models predict the muscle’s response to a specified input based on experimental measurements. Prominent phenomenological models are the Hill-type muscle models, which have been incorporated into rigid-body modeling frameworks, and three-dimensional continuum-mechanical models. Biophysically based models attempt to predict the muscle’s response as emerging from the underlying physiology of the system. In this contribution, the conventional biophysically based modeling methodology is extended to include several structural and functional characteristics of skeletal muscle. The result is a physiologically based, multi-scale skeletal muscle finite element model that is capable of representing detailed, geometrical descriptions of skeletal muscle fibers and their grouping. Together with a well-established model of motor-unit recruitment, the electro-physiological behavior of single muscle fibers within motor units is computed and linked to a continuum-mechanical constitutive law. The bridging between the cellular level and the organ level has been achieved via a multi-scale constitutive law and homogenization. The effect of homogenization has been investigated by varying the number of embedded skeletal muscle fibers and/or motor units and computing the resulting exerted muscle forces while applying the same excitatory input. All simulations were conducted using an anatomically realistic finite element model of the tibialis anterior muscle. Given the fact that the underlying electro-physiological cellular muscle model is capable of modeling metabolic fatigue effects such as potassium accumulation in the T-tubular space and inorganic phosphate build-up, the proposed framework provides a novel simulation-based way to investigate muscle behavior ranging from motor-unit recruitment to force generation and fatigue. PMID:22993509

Effect of different sintering temperature on fly ash based geopolymer artificial aggregate

NASA Astrophysics Data System (ADS)

Abdullah, Alida; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Tahir, Muhammad Faheem Mohd

2017-04-01

This research was conducted to study the mechanical and morphology of fly ash based geopolymer as artificial aggregate at different sintering temperature. The raw material that are used is fly ash, sodium hydroxide, sodium silicate, geopolymer artificial aggregate, Ordinary Portland Cement (OPC), coarse aggregate and fine aggregate. The research starts with the preparation of geopolymer artificial aggregate. Then, geopolymer artificial aggregate will be sintered at six difference temperature that is 400°C, 500°C, 600°C, 700°C, 800°C and 900°C to known at which temperature the geopolymer artificial aggregate will become a lightweight aggregate. In order to characterize the geopolymer artificial aggregate the X-ray Diffraction (XRD) and X-Ray Fluorescence (XRF) was done. The testing and analyses involve for the artificial aggregate is aggregate impact test, specific gravity test and Scanning Electron Microscopy (SEM). After that the process will proceed to produce concrete with two type of different aggregate that is course aggregate and geopolymer artificial aggregate. The testing for concrete is compressive strength test, water absorption test and density test. The result obtained will be compared and analyse.

Tracheal smooth muscle responses to substance P and neurokinin A in the piglet.

PubMed

Haxhiu-Poskurica, B; Haxhiu, M A; Kumar, G K; Miller, M J; Martin, R J

1992-03-01

The tachykinins substance P (SP) and neurokinin A (NKA) have been shown to induce airway smooth muscle contraction in mature animals, and the enzyme neutral endopeptidase (NEP) modulates this effect. We evaluated maturation of SP- and NKA-induced tracheal smooth muscle contraction and modulation of their effects by NEP in anesthetized, paralyzed, and artificially ventilated piglets less than 4 days, 2-3 wk, and 10 wk of age. Tracheal smooth muscle tension was measured in vivo from an open tracheal segment by use of a force transducer. Intravenous SP caused a dose-dependent increase in tracheal tension in all three age groups; however, the response in less than 4-day-old piglets was significantly weaker than in 2- to 3- and 10-wk-old piglets. NKA caused a dose-dependent increase in tracheal tension only in 2- to 3- and 10-wk-old piglets. The response of tracheal tension to NKA was weaker than the response to SP in all age groups. Atropine (2 mg/kg) significantly diminished the responses of tracheal tension to SP and NKA, indicating a cholinergic contribution to these responses at all ages. Intravenous thiorphan, a known NEP inhibitor, potentiated the effects of SP only in 2- to 3- and 10-wk-old piglets and did not affect the response of tracheal tension to NKA at any age. Biochemical analyses demonstrated a significant increase in tracheal NEP activity in comparably aged piglets over the first 10 wk of life.(ABSTRACT TRUNCATED AT 250 WORDS)

An Accurate and Dynamic Computer Graphics Muscle Model

NASA Technical Reports Server (NTRS)

Levine, David Asher

1997-01-01

A computer based musculo-skeletal model was developed at the University in the departments of Mechanical and Biomedical Engineering. This model accurately represents human shoulder kinematics. The result of this model is the graphical display of bones moving through an appropriate range of motion based on inputs of EMGs and external forces. The need existed to incorporate a geometric muscle model in the larger musculo-skeletal model. Previous muscle models did not accurately represent muscle geometries, nor did they account for the kinematics of tendons. This thesis covers the creation of a new muscle model for use in the above musculo-skeletal model. This muscle model was based on anatomical data from the Visible Human Project (VHP) cadaver study. Two-dimensional digital images from the VHP were analyzed and reconstructed to recreate the three-dimensional muscle geometries. The recreated geometries were smoothed, reduced, and sliced to form data files defining the surfaces of each muscle. The muscle modeling function opened these files during run-time and recreated the muscle surface. The modeling function applied constant volume limitations to the muscle and constant geometry limitations to the tendons.

Use of latissimus dorsi muscle onlay patch alternative to acellular dermal matrix in implant-based breast reconstruction

PubMed Central

Lee, Jeeyeon

2015-01-01

Background An acellular dermal matrix (ADM) is applied to release the surrounding muscles and prevent dislocation or rippling of the implant. We compared implant-based breast reconstruction using the latissimus dorsi (LD) muscle, referred to as an “LD muscle onlay patch,” with using an ADM. Method A total of 56 patients (60 breasts) underwent nipple sparing mastectomy with implant-based breast reconstruction using an ADM or LD muscle onlay patch. Cosmetic outcomes were assessed 4 weeks after chemotherapy or radiotherapy, and statistical analyses were performed. Results Mean surgical time and hospital stay were significantly longer in the LD muscle onlay patch group than the ADM group. However, there were no statistically significant differences between groups in postoperative complications. Cosmetic outcomes for breast symmetry and shape were higher in the LD muscle onlay patch group. Conclusions Implant-based breast reconstruction with an LD muscle onlay patch would be a feasible alternative to using an ADM. PMID:26161312

Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators

DOE PAGES

Chen, Xi; Goodnight, Davis; Gao, Zhenghan; ...

2015-06-16

Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth’s climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. In this work, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air–water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on watermore » while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.« less

Design and Simulation of Optically Actuated Bistable MEMS

NASA Astrophysics Data System (ADS)

Lucas, Thomas; Moiseeva, Evgeniya; Harnett, Cindy

2012-02-01

In this project, bistable three-dimensional MEMS actuators are designed to be optically switched between stable states for biological research applications. The structure is a strained rectangular frame created with stress-mismatched metal-oxide bilayers. The devices curl into an arc in one of two directions tangent to the substrate, and can switch orientation when regions are selectively heated. The heating is powered by infrared laser, and localized with patterned infrared-resonant gold nanoparticles on critical regions. The enhanced energy absorption on selected areas provides switching control and heightened response to narrow-band infrared light. Coventorware has been used for finite element analysis of the system. The numerical simulations indicate that it has two local minimum states with extremely rapid transition time (<<0.1 s) when the structure is thermally deformed. Actuation at laser power and thermal limits compatible with physiological applications will enable microfluidic pumping elements and fundamental studies of tissue response to three-dimensional mechanical stimuli, artificial-muscle based pumps and other biomedical devices triggered by tissue-permeant infrared light.

Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xi; Goodnight, Davis; Gao, Zhenghan

Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth’s climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. In this work, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air–water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on watermore » while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.« less

Effect of the mechanical deformation on the electrical properties of the polymer/CNT fiber

NASA Astrophysics Data System (ADS)

Cho, Hyun Woo; Sung, Bong June; Nano-Bio Computational Chemistry Laboratory Team

2014-03-01

We elucidate the effect of the mechanical deformation on the electrical properties of the polymer/CNT fiber. The conductive polymer fiber has drawn a great attention for its potential application to a stretchable electronics such as wearable devices and artificial muscles, etc. However, the electrical conductivity of the polymer-based stretchable electronics decreases significantly during the deformation, which may limit the applicability of the polymer/CNT fiber for the stretchable electronics. Moreover, its physical origin for the decrease in electrical conductivity has not been explained clearly. In this work, we employ a coarse-grained model for the polymer/CNT fiber, and we calculate the electric conductivity using global tunneling network (GTN) model. We show that the electric conductivity decreases during the elongation of the polymer/CNT fiber. We also find using critical path approximation (CPA) that the structure of the electrical network of the CNTs changes collectively during the elongation of the fiber, which is strongly responsible for the reduction of the electrical conductivity of the polymer/CNT fiber.

Multifunctionality and Control of the Crumpling and Unfolding of Large-Area Graphene

PubMed Central

Zang, Jianfeng; Ryu, Seunghwa; Pugno, Nicola; Wang, Qiming; Tu, Qing; Buehler, Markus J.; Zhao, Xuanhe

2012-01-01

Crumpled graphene films are broadly used, for instance in electronics1, energy storage2, 3, composites4, 5, and biomedicine6. Although it is known that the degree of crumpling affects graphene's properties and the performance of graphene-based devices and materials3, 5, 7, the controlled folding and unfolding of crumpled graphene films has not been demonstrated. Here we report an approach to reversibly control the crumpling and unfolding of large-area graphene sheets. We show with experiments, atomistic simulations and theory that, by harnessing the mechanical instabilities of graphene adhered on a biaxially pre-stretched polymer substrate and by controlling the relaxation of the pre-strains in a particular order, graphene films can be crumpled into tailored self-organized hierarchical structures that mimic superhydrophobic leaves. The approach enables us to fabricate large-area conductive coatings and electrodes showing superhydrophobicity, high transparency, and tunable wettability and transmittance. We also demonstrate that crumpled graphene-polymer laminates can be used as artificial-muscle actuators. PMID:23334002

A variable stiffness dielectric elastomer actuator based on electrostatic chucking.

PubMed

Imamura, Hiroya; Kadooka, Kevin; Taya, Minoru

2017-05-14

Dielectric elastomer actuators (DEA) are one type of promising artificial muscle; however, applications of bending-type DEA for robotic end-effectors may be limited by their low stiffness and ability to resist external loads without buckling. Unimorph DEA can produce large out-of-plane deformation suitable for use as robotic end effectors; however, design of such actuators for large displacement comes at the cost of low stiffness and blocking force. This work proposes and demonstrates a variable stiffness dielectric elastomer actuator (VSDEA) consisting of a plurality of unimorph DEA units operating in parallel, which can exhibit variable electrostatic chucking to modulate the structure's bending stiffness. The unimorph DEA units are additively manufactured using a high-resolution pneumatic dispenser, and VSDEA comprising various numbers of units are assembled. The performance of the DEA units and VSDEA are compared to model predictions, exhibiting a maximum stiffness change of 39.2×. A claw actuator comprising two VSDEA and weighing 0.6 grams is demonstrated grasping and lifting a 10 gram object.

One-volt-driven superfast polymer actuators based on single-ion conductors

PubMed Central

Kim, Onnuri; Kim, Hoon; Choi, U. Hyeok; Park, Moon Jeong

2016-01-01

The key challenges in the advancement of actuator technologies related to artificial muscles include fast-response time, low operation voltages and durability. Although several researchers have tackled these challenges over the last few decades, no breakthrough has been made. Here we describe a platform for the development of soft actuators that moves a few millimetres under 1 V in air, with a superfast response time of tens of milliseconds. An essential component of this actuator is the single-ion-conducting polymers that contain well-defined ionic domains through the introduction of zwitterions; this achieved an exceptionally high dielectric constant of 76 and a 300-fold enhancement in ionic conductivity. Moreover, the actuator demonstrated long-term durability, with negligible changes in the actuator stroke over 20,000 cycles in air. Owing to its low-power consumption (only 4 mW), we believe that this actuator could pave the way for cutting-edge biomimetic technologies in the future. PMID:27857067

The mechanical design of a humanoid robot with flexible skin sensor for use in psychiatric therapy

NASA Astrophysics Data System (ADS)

Burns, Alec; Tadesse, Yonas

2014-03-01

In this paper, a humanoid robot is presented for ultimate use in the rehabilitation of children with mental disorders, such as autism. Creating affordable and efficient humanoids could assist the therapy in psychiatric disability by offering multimodal communication between the humanoid and humans. Yet, the humanoid development needs a seamless integration of artificial muscles, sensors, controllers and structures. We have designed a human-like robot that has 15 DOF, 580 mm tall and 925 mm arm span using a rapid prototyping system. The robot has a human-like appearance and movement. Flexible sensors around the arm and hands for safe human-robot interactions, and a two-wheel mobile platform for maneuverability are incorporated in the design. The robot has facial features for illustrating human-friendly behavior. The mechanical design of the robot and the characterization of the flexible sensors are presented. Comprehensive study on the upper body design, mobile base, actuators selection, electronics, and performance evaluation are included in this paper.

Log-linear model based behavior selection method for artificial fish swarm algorithm.

PubMed

Huang, Zhehuang; Chen, Yidong

2015-01-01

Artificial fish swarm algorithm (AFSA) is a population based optimization technique inspired by social behavior of fishes. In past several years, AFSA has been successfully applied in many research and application areas. The behavior of fishes has a crucial impact on the performance of AFSA, such as global exploration ability and convergence speed. How to construct and select behaviors of fishes are an important task. To solve these problems, an improved artificial fish swarm algorithm based on log-linear model is proposed and implemented in this paper. There are three main works. Firstly, we proposed a new behavior selection algorithm based on log-linear model which can enhance decision making ability of behavior selection. Secondly, adaptive movement behavior based on adaptive weight is presented, which can dynamically adjust according to the diversity of fishes. Finally, some new behaviors are defined and introduced into artificial fish swarm algorithm at the first time to improve global optimization capability. The experiments on high dimensional function optimization showed that the improved algorithm has more powerful global exploration ability and reasonable convergence speed compared with the standard artificial fish swarm algorithm.

Modification of rat detrusor muscle contraction by ascorbic acid and citric acid involving enhanced neurotransmitter release and Ca2+ influx.

PubMed

Dasgupta, Jaydip; Elliott, Ruth A; Tincello, Douglas G

2009-01-01

Consumption of carbonated soft drinks is independently associated with the development of overactive bladder (OR 1.41, 95% Cl 1.02-1.95). We have shown previously that artificial sweeteners, present in carbonated soft drinks, enhanced detrusor muscle contraction. Other constituents of soft drinks are preservatives and antioxidants, we evaluated the effects of two of these, ascorbic acid and citric acid, on the contractile response of isolated rat bladder muscle strips. Detrusor muscle strips were suspended in a perfusion organ bath. We determined the effect of ascorbic acid and citric acid on the contractile responses to electrical field stimulation (EFS) in the absence and presence of atropine, carbachol, alpha, beta methylene ATP, potassium and calcium. Ascorbic acid and citric acid (10(-7) M to 10(-3) M) enhanced the contractile response to 10 Hz EFS compared to control (P < 0.01). The frequency and amplitude of spontaneous bladder contractions were enhanced in the presence of ascorbic acid and citric acid by 14%, 21%, 21%, and 11% respectively. Ascorbic acid 10(-4) M significantly increased the atropine resistant response to EFS 5 Hz by 37% (P < 0.01) and inhibited contraction in response to carbachol 10(-4) M by 24%, (P < 0.05). Both ascorbic acid 10(-4) M and citric acid 10(-5) M significantly enhanced maximum contractile responses to alpha, beta methylene ATP, KCI and calcium compared to control. Ascorbic acid and citric acid augmented bladder muscle contraction possibly by enhanced Ca(2+) influx. Presynaptic neurotransmitter release was enhanced by ascorbic acid. Carbonated beverages containing preservatives may aggravate symptoms of OAB. (c) 2009 Wiley-Liss, Inc.

A Prospective Analysis of the Injury Incidence of Young Male Professional Football Players on Artificial Turf

PubMed Central

Bianco, Antonino; Spedicato, Mirco; Petrucci, Marco; Messina, Giuseppe; Thomas, Ewan; Nese Sahin, Fatma; Paoli, Antonio; Palma, Antonio

2016-01-01

Background: The effects of synthetic surfaces on the risk of injuries is still debated in literature and the majority of published data seems to be contradictory. For such reasons the understanding of injury incidence on such surfaces, especially in youth sport, is fundamental for injury prevention. Objectives: The aim of this study was to prospectively report the epidemiology of injuries in young football players, playing on artificial turfs, during a one sports season. Patients and Methods: 80 young male football players (age 16.1 ± 3.7 years; height 174 ± 6.6 cm; weight 64.2 ± 6.3 kg) were enrolled in a prospective cohort study. The participants were then divided in two groups; the first included players age ranging from 17 to 19 (OP) whereas the second included players age ranging from 13 to 16 (YP). Injury incidence was recorded prospectively, according to the consensus statement for soccer. Results: A total of 107 injuries (35 from the OP and 72 from the YP) were recorded during an exposure time of 83.760 hours (incidence 1.28/1000 per player hours); 22 during matches (incidence 2.84/1000 per player hours, 20.5%) and 85 during training (incidence 1.15/1000 per player hours, 79.5%). Thigh and groin were the most common injury locations (33.6% and 21.5%, respectively) while muscle injuries such as contractures and strains were the most common injury typologies (68.23%). No statistical differences between groups were displayed, except for the rate of severe injuries during matches, with the OP displaying slightly higher rates compared to the YP. Severe injuries accounted for 10.28% of the total injuries reported. The average time lost due to injuries was 14 days. Re-injuries accounted for 4.67% of all injuries sustained during the season. Conclusions: In professional youth soccer injury rates are reasonably low. Muscle injuries are the most common type of injuries while groin and thigh the most common locations. Artificial turf pitches don’t seem to contribute to injury incidence in young football players. PMID:27217929

Magnetic skyrmion-based artificial neuron device

NASA Astrophysics Data System (ADS)

Li, Sai; Kang, Wang; Huang, Yangqi; Zhang, Xichao; Zhou, Yan; Zhao, Weisheng

2017-08-01

Neuromorphic computing, inspired by the biological nervous system, has attracted considerable attention. Intensive research has been conducted in this field for developing artificial synapses and neurons, attempting to mimic the behaviors of biological synapses and neurons, which are two basic elements of a human brain. Recently, magnetic skyrmions have been investigated as promising candidates in neuromorphic computing design owing to their topologically protected particle-like behaviors, nanoscale size and low driving current density. In one of our previous studies, a skyrmion-based artificial synapse was proposed, with which both short-term plasticity and long-term potentiation functions have been demonstrated. In this work, we further report on a skyrmion-based artificial neuron by exploiting the tunable current-driven skyrmion motion dynamics, mimicking the leaky-integrate-fire function of a biological neuron. With a simple single-device implementation, this proposed artificial neuron may enable us to build a dense and energy-efficient spiking neuromorphic computing system.

Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

NASA Astrophysics Data System (ADS)

Fernandez-Jover, Damian; Martinez-Rubio, Laura; Sanchez-Jerez, Pablo; Bayle-Sempere, Just T.; Lopez Jimenez, Jose Angel; Martínez Lopez, Francisco Javier; Bjørn, Pål-Arne; Uglem, Ingebrigt; Dempster, Tim

2011-03-01

Aquaculture of carnivorous fish species in sea-cages typically uses artificial feeds, with a proportion of these feeds lost to the surrounding environment. This lost resource may provide a trophic subsidy to wild fish in the vicinity of fish farms, yet the physiological consequences of the consumption of waste feed by wild fish remain unclear. In two regions in Norway with intensive aquaculture, we tested whether wild saithe ( Pollachius virens) and Atlantic cod ( Gadus morhua) associated with fish farms (F assoc), where waste feed is readily available, had modified diets, condition and fatty acid (FA) compositions in their muscle and liver tissues compared to fish unassociated (UA) with farms. Stomach content analyses revealed that both cod and saithe consumed waste feed in the vicinity of farms (6-96% of their diet was composed of food pellets). This translated into elevated body and liver condition compared to fish caught distant from farms for cod at both locations and elevated body condition for saithe at one of the locations. As a consequence of a modified diet, we detected significantly increased concentrations of terrestrial-derived fatty acids (FAs) such as linoleic (18:2ω6) and oleic (18:1ω9) acids and decreased concentrations of DHA (22:6ω3) in the muscle and/or liver of F assoc cod and saithe when compared with UA fish. In addition, the ω3:ω6 ratio clearly differed between F assoc and UA fish. Linear discriminant analysis (LDA) correctly classified 97% of fish into F assoc or UA origin for both cod and saithe based on the FA composition of liver tissues, and 89% of cod and 86% of saithe into F assoc or UA origin based on the FA composition of muscle. Thus, LDA appears a useful tool for detecting the influence of fish farms on the FA composition of wild fish. Ready availability of waste feed with high protein and fat content provides a clear trophic subsidy to wild fish in coastal waters, yet whether the accompanying side-effect of altered fatty acid compositions affects physiological performance or reproductive potential requires further research.

Applications of artificial intelligence V; Proceedings of the Meeting, Orlando, FL, May 18-20, 1987

NASA Technical Reports Server (NTRS)

Gilmore, John F. (Editor)

1987-01-01

The papers contained in this volume focus on current trends in applications of artificial intelligence. Topics discussed include expert systems, image understanding, artificial intelligence tools, knowledge-based systems, heuristic systems, manufacturing applications, and image analysis. Papers are presented on expert system issues in automated, autonomous space vehicle rendezvous; traditional versus rule-based programming techniques; applications to the control of optional flight information; methodology for evaluating knowledge-based systems; and real-time advisory system for airborne early warning.

Challenges facing the distribution of an artificial-intelligence-based system for nursing.

PubMed

Evans, S

1985-04-01

The marketing and successful distribution of artificial-intelligence-based decision-support systems for nursing face special barriers and challenges. Issues that must be confronted arise particularly from the present culture of the nursing profession as well as the typical organizational structures in which nurses predominantly work. Generalizations in the literature based on the limited experience of physician-oriented artificial intelligence applications (predominantly in diagnosis and pharmacologic treatment) must be modified for applicability to other health professions.

A Multiagent Based Model for Tactical Planning

DTIC Science & Technology

2002-10-01

Pub. Co. 1985. [10] Castillo, J.M. Aproximación mediante procedimientos de Inteligencia Artificial al planeamiento táctico. Doctoral Thesis...been developed under the same conceptual model and using similar Artificial Intelligence Tools. We use four different stimulus/response agents in...The conceptual model is built on base of the Agents theory. To implement the different agents we have used Artificial Intelligence techniques such