A Transverse Contour Model of Distributed Muscle Forces and Spinal Loads during Lifting and Twisting

1997 ◽  
Vol 41 (1) ◽  
pp. 675-679 ◽  
Author(s):  
Joseph R. Davis ◽  
Gary A. Mirka
Keyword(s):  
System Analysis ◽  
Dimensional Space ◽  
Human Subjects ◽  
Three Dimensional ◽  
Trunk Muscles ◽  
Complex Nature ◽  
Muscle Forces ◽  
Contour Model ◽  
Fine Wire

This study has developed a realistic three-dimensional transverse contour model of distributed muscle forces and spinal consequences (compression, torsion, and shear) that occur during dynamic lifting, static holding, and dynamic twisting. The model utilizes multiple force vectors to represent broad flat muscles along with traditional single vector modeling of other trunk muscles. Instead of a two-dimensional transverse cutting plane, this model introduces a system analysis boundary in the form of a three-dimensional transverse cutting contour that was created by in vivo digitization of human subjects in symmetric and asymmetric postures. This transverse contour more realistically illustrates the complex nature of the human biomechanical system during the performance of industrial work in three-dimensional space. To investigate this model, surface electromyography data were collected from seven subjects. Also, to confirm the findings from surface data and to alleviate muscle signal crosstalk concerns, fine-wire electromyography data were collected from one additional subject. Both the surface and fine-wire data showed that differential muscle forces existed within each of the external obliques, internal obliques, and latissimus dorsi. Moreover, the data were used for validation which confirmed the viability of the model. This multi-vector distributed-force transverse contour model was found to be particularly useful for describing shear and compression during three-dimensional twisting.

The Effect of Lifting vs. Lowering on Spinal Loading

1996 ◽  
Vol 40 (13) ◽  
pp. 599-603 ◽  
Author(s):  
Kermit G. Davis
Keyword(s):  
Muscle Activity ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Muscle Forces ◽  
Shear Forces ◽  
Spinal Loading ◽  
Spinal Loads ◽  
Trunk Strength ◽  
Anterior Posterior ◽  
Three Dimensional Space

In industry, workers perform tasks requiring both lifting and lowering. During concentric lifting, the muscles are shortening as the force is being generated. Conversely, the muscle lengthens while generating force during eccentric lowering. While research on various lifting tasks is extensive, there has been limited research performed to evaluate the lowering tasks. Most of the research that does exist on lowering has investigated muscle activity and trunk strength. None of these studies have investigated spinal loading. The current study estimated the effects of lifting and lowering on spinal loads and predicted moments imposed on the spine. Ten subjects performed both eccentric and concentric lifts under sagittally symmetric conditions. The tasks were performed under isokinetic trunk velocities of 5, 10, 20, 40, and 80 deg/s while holding a box with weights of 9.1, 18.2, and 27.3 kg. Spinal loads and predicted moments in three dimensional space were estimated by an EMG-assisted model which has been adjusted to incorporate the artifacts of eccentric lifting. Eccentric strength was found to be 56 percent greater than during concentric lifting. The lowering tasks produced significantly higher compression forces but lower anterior-posterior shear forces than the concentric lifting tasks. The differences in the spinal loads between the two lifting tasks were attributed to the internal muscle forces and unequal moments resulting from differences in the lifting path of the box. Thus, the differences between the lifting tasks resulted from different lifting styles associated with eccentric and concentric movements

Regulation of 3D Human Arm Impedance Through Muscle Co-Contraction

2013 ◽  
Author(s):  
Harshil Patel ◽  
Gerald O’Neill ◽  
Panagiotis Artemiadis
Keyword(s):  
Dimensional Space ◽  
Human Subjects ◽  
Three Dimensional ◽  
Mechanical Impedance ◽  
Dominant Factor ◽  
Robot Arm ◽  
End Point ◽  
Human Arm ◽  
Arm Muscles ◽  
Experimental Trials

Humans have the inherent ability of performing highly dexterous and skillful tasks with their arms, involving maintenance of posture, movement, and interaction with the environment. The latter requires the human to control the dynamic characteristics of the upper limb musculoskeletal system. These characteristics are quantitatively represented by inertia, damping, and stiffness, which are measures of mechanical impedance. Many previous studies have shown that arm posture is a dominant factor in determining the end point impedance on a horizontal (transverse) plane. This paper presents the characterization of the end point impedance of the human arm in three-dimensional space. Moreover, it models the regulation of the arm impedance with respect to various levels of muscle co-contraction. The characterization is made by route of experimental trials where human subjects maintained arm posture while their arms were perturbed by a robot arm. Furthermore, the subjects were asked to control the level of their arm muscles’ co-contraction, using visual feedback of their muscles’ activation, in order to investigate the effect of this muscle co-contraction on the arm impedance. The results of this study show a very interesting, anisotropic increase of arm stiffness due to muscle co-contraction. These results could lead to very useful conclusions about the human’s arm biomechanics, as well as many implications for human motor control-specifically the control of arm impedance through muscle co-contraction.

In Vivo Dynamic Strains of the Mitral Valve Annulus

2007 ◽  
Author(s):  
Brett Zubiate ◽  
Michael Sacks ◽  
Robert C. Gorman ◽  
Joseph H. Gorman
Keyword(s):  
Mitral Valve ◽  
Cardiac Cycle ◽  
Dimensional Space ◽  
Complex Structure ◽  
Three Dimensional ◽  
Mitral Annulus ◽  
Mitral Valve Leaflet ◽  
Valve Function ◽  
Integrated Operation

The mitral valve apparatus is a complex structure with multiple components that require seamless, integrated operation for normal valve function. One of these components is the annulus, a fibrous ring of tissue that defines the boundary between the mitral valve leaflets and the surrounding superstructure of the heart. During the cardiac cycle the annulus undergoes large deformations and dramatic shape changes. Moreover, the annulus motion represents a key boundary condition for mitral valve leaflet deformation. Yet, to date our knowledge of the subtle deformations this structure undergoes during the cardiac cycle remains very limited. In the present study, an array of 1 mm diameter piezoelectric sonocrystals was implanted in 5 sheep to quantify annular deformation over the complete cardiac cycle. These crystals act as fiducial markers for the mitral annulus with a temporal resolution of ∼1ms and a special resolution of .01mm in a calibrated three dimensional space. A quintic order generalized 3D spline was developed to reconstruct the annular geometry.

scholarly journals An Implantable Sensorized Lead for Continuous Monitoring of Cardiac Apex Rotation

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4195
Author(s):  
Emanuela Marcelli ◽  
Laura Cercenelli
Keyword(s):  
Continuous Monitoring ◽  
Dimensional Space ◽  
Animal Experiments ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Cardiac Monitoring ◽  
Cardiac Apex ◽  
Angular Velocities

Changes in the pattern or amplitude of cardiac rotation have been associated with important cardiovascular diseases, including Heart Failure (HF) which is one of the major health problems worldwide. Recent advances in echocardiographic techniques have allowed for non-invasive quantification of cardiac rotation; however, these examinations do not address the continuous monitoring of patient status. We have presented a newly developed implantable, transvenous lead with a tri-axis (3D) MEMS gyroscope incorporated near its tip to measure cardiac apex rotation in the three-dimensional space. We have named it CardioMon for its intended use for cardiac monitoring. If compared with currently proposed implantable systems for HF monitoring based on the use of pressure sensors that can have reliability issues, an implantable motion sensor like a gyroscope holds the premise for more reliable long term monitoring. The first prototypal assembly of the CardioMon lead has been tested to assess the reliability of the 3D gyroscope readings. In vitro results showed that the novel sensorized CardioMon lead was accurate and reliable in detecting angular velocities within the range of cardiac twisting velocities. Animal experiments will be planned to further evaluate the CardioMon lead in in vivo environments and to investigate possible endocardial implantation sites.

scholarly journals Ranges of Cervical Intervertebral Disc Deformation During an In Vivo Dynamic Flexion–Extension of the Neck

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Yan Yu ◽  
Haiqing Mao ◽  
Jing-Sheng Li ◽  
Tsung-Yuan Tsai ◽  
Liming Cheng ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Imaging System ◽  
Human Subjects ◽  
Three Dimensional ◽  
Cervical Disc ◽  
Significant Difference ◽  
Flexion Extension ◽  
Fluoroscopic Imaging ◽  
Magnetic Resonance Imaging Mri

While abnormal loading is widely believed to cause cervical spine disc diseases, in vivo cervical disc deformation during dynamic neck motion has not been well delineated. This study investigated the range of cervical disc deformation during an in vivo functional flexion–extension of the neck. Ten asymptomatic human subjects were tested using a combined dual fluoroscopic imaging system (DFIS) and magnetic resonance imaging (MRI)-based three-dimensional (3D) modeling technique. Overall disc deformation was determined using the changes of the space geometry between upper and lower endplates of each intervertebral segment (C3/4, C4/5, C5/6, and C6/7). Five points (anterior, center, posterior, left, and right) of each disc were analyzed to examine the disc deformation distributions. The data indicated that between the functional maximum flexion and extension of the neck, the anterior points of the discs experienced large changes of distraction/compression deformation and shear deformation. The higher level discs experienced higher ranges of disc deformation. No significant difference was found in deformation ranges at posterior points of all the discs. The data indicated that the range of disc deformation is disc level dependent and the anterior region experienced larger changes of deformation than the center and posterior regions, except for the C6/7 disc. The data obtained from this study could serve as baseline knowledge for the understanding of the cervical spine disc biomechanics and for investigation of the biomechanical etiology of disc diseases. These data could also provide insights for development of motion preservation surgeries for cervical spine.

scholarly journals Biohybrid Microswimmers Against Bacterial Infections

2021 ◽  
Author(s):  
Inga S. Shchelik ◽  
João V. D. Molino ◽  
Karl Gademann
Keyword(s):  
Bacterial Infections ◽  
Surface Engineering ◽  
High Efficiency ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Covalent Attachment ◽  
Temporal Control ◽  
Selective Treatment ◽  
On Demand

Biohybrid microswimmers exploit the natural abilities of motile microorganisms e.g. in releasing cargo on-demand with high spatial and temporal control. However, using such engineered swarms to deliver antibiotics addressing bacterial infections has not yet been realized. In the present study, a design strategy for biohybrid microswimmers is reported, which features the covalent attachment of antibiotics to the motile green algae Chlamydomonas reinhardtii via a photo-cleavable linker. The surface engineering of the algae does not rely on genetic manipulations, proceeds with high efficiency, does not impair the viability or phototactic ability of microalgae, and allows for caging of the antibiotic on the surface for subsequent release via external stimuli. Two different antibiotic classes have been separately utilized, which result in activity against both gram-positive and gram-negative strains. Guiding the biohybrid microswimmers by an external beacon, and on-demand delivery of the drugs by light with high spatial and temporal control, allowed for strong inhibition of bacterial growth in vivo. This efficient strategy could potentially allow for the selective treatment of bacterial infections by engineered algal microrobots with high precision in space and time. Overall, this work presents an operationally simple production of biohybrid microswimmers loaded with antibiotic cargo to combat bacterial infections precisely delivered in three-dimensional space.

On the method for the analysis of compulsive phase mixing and its application in cosmogony

2021 ◽  
pp. 83-88
Author(s):  
S. N. NURITDINOV ◽  
A. A. MUMINOV ◽  
F. U. BOTIROV
Keyword(s):  
Phase Space ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Volume Element ◽  
Numerical Calculations ◽  
Complex Nature ◽  
Phase Volume ◽  
Phase Mixing ◽  
Stationary Stochastic Processes ◽  
Gravitating Systems

In this paper, we study the strong non-stationary stochastic processes that take place in the phase space of self-gravitating systems at the earlier non-stationary stage of their evolution. The numerical calculations of the compulsive phase mixing process were carried out according to the model of chaotic impacts, where the initially selected phase volume experiences random pushes that are of a diverse and complex nature. The application of the method for studying random impacts on a volume element in the case of three-dimensional space is carried out.

Surface Reconstruction of In Vivo Geometry Based on Medical Images Using Multilevel Radial Basis Functions

2004 ◽  
Author(s):  
Yoke Kong Kuan ◽  
Paul F. Fischer ◽  
Francis Loth
Keyword(s):  
Radial Basis Functions ◽  
Surface Reconstruction ◽  
Medical Images ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Basis Functions ◽  
Radial Basis ◽  
Point Set ◽  
Three Dimensional Space

Compactly supported radial basis functions (RBFs) were used for surface reconstruction of in vivo geometry, translated from two dimensional (2D) medical images. RBFs provide a flexible approach to interpolation and approximation for problems featuring unstructured data in three-dimensional space. Point-set data are obtained from the contour of segmented 2-D slices. Multilevel RBFs allow smoothing and fill in missing data of the original geometry while maintaining the overall structure shape.

In Vivo Determination of the Direction of Rotation and Moment-Angle Relationship of Individual Elbow Muscles

1998 ◽  
Vol 120 (5) ◽  
pp. 625-633 ◽  
Author(s):  
L. Zhang ◽  
J. Butler ◽  
T. Nishida ◽  
G. Nuber ◽  
H. Huang ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Elbow Flexion ◽  
Joint Movement ◽  
Flexion Extension ◽  
Relationship Of ◽  
Three Dimensional Space

The direction of rotation (DOR) of individual elbow muscles, defined as the direction in which a muscle rotates the forearm relative to the upper arm in three-dimensional space, was studied in vivo as a function of elbow flexion and forearm rotation. Electrical stimulation was used to activate an individual muscle selectively, and the resultant flexion-extension, supination-pronation, and varus-valgus moments were used to determine the DOR. Furthermore, multi-axis moment-angle relationships of individual muscles were determined by stimulating the muscle at a constant submaximal level across different joint positions, which was assumed to result in a constant level of muscle activation. The muscles generate significant moments about axes other than flexion-extension, which is potentially important for actively controlling joint movement and maintaining stability about all axes. Both the muscle DOR and the multi axis moments vary with the joint position systematically. Variations of the DOR and moment-angle relationship across muscle twitches of different amplitudes in a subject were small, while there were considerable variations between subjects.

scholarly journals Numerical Simulations of MREIT Conductivity Imaging for Brain Tumor Detection

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Zi Jun Meng ◽  
Saurav Z. K. Sajib ◽  
Munish Chauhan ◽  
Rosalind J. Sadleir ◽  
Hyung Joong Kim ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Human Subjects ◽  
Three Dimensional ◽  
Tumor Detection ◽  
Head Model ◽  
Impedance Tomography ◽  
The Brain ◽  
T System ◽  
Brain Tissues

Magnetic resonance electrical impedance tomography (MREIT) is a new modality capable of imaging the electrical properties of human body using MRI phase information in conjunction with external current injection. Recentin vivoanimal and human MREIT studies have revealed unique conductivity contrasts related to different physiological and pathological conditions of tissues or organs. When performingin vivobrain imaging, small imaging currents must be injected so as not to stimulate peripheral nerves in the skin, while delivery of imaging currents to the brain is relatively small due to the skull’s low conductivity. As a result, injected imaging currents may induce small phase signals and the overall low phase SNR in brain tissues. In this study, we present numerical simulation results of the use of head MREIT for brain tumor detection. We used a realistic three-dimensional head model to compute signal levels produced as a consequence of a predicted doubling of conductivity occurring within simulated tumorous brain tissues. We determined the feasibility of measuring these changes in a time acceptable to human subjects by adding realistic noise levels measured from a candidate 3 T system. We also reconstructed conductivity contrast images, showing that such conductivity differences can be both detected and imaged.

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