Response of a Hodgkin-Huxley neuron to a high-frequency input
L. S. Borkowski
We study the response of a Hodgkin-Huxley neuron stimulated by a periodic sequence of conductance pulses arriving through the synapse in the high-frequency regime. In addition to the usual excitation threshold there is a smooth crossover from the firing to the silent regime for increasing pulse ampl ... [Phys. Rev. E 80, 051914 (2009)] published Thu Nov 19, 2009.
Statistical physics of cerebral embolization leading to stroke
J. P. Hague and E. M. L. Chung
We discuss the physics of embolic stroke using a minimal model of emboli moving through the cerebral arteries. Our model of the blood flow network consists of a bifurcating tree into which we introduce particles (emboli) that halt flow on reaching a node of similar size. Flow is weighted away from b ... [Phys. Rev. E 80, 051912 (2009)] published Wed Nov 18, 2009.
Arterial wall tethering as a distant boundary condition
S. Hodis and M. Zamir
A standing difficulty in the problem of blood vessel tethering has been that only one of the two required boundary conditions can be fully specified, namely, that at the inner (endothelial) wall surface. The other, at the outer layer of the vessel wall, is not known except in the limiting case where ... [Phys. Rev. E 80, 051913 (2009)] published Wed Nov 18, 2009.
Scale and Boundary Conditions Effects on the Apparent Elastic Moduli of Trabecular Bone Modeled as a Periodic Cellular Solid
Congyu Wang, Liang Feng, and Iwona Jasiuk
We study apparent elastic moduli of trabecular bone, which is represented, for simplicity, by a two- or three-dimensional periodic cellular network. The term apparent refers to the case when the region used in calculations (or specimen size) is smaller than a representative volume element and the mo ... [J. Biomech. Eng. 131, 121008 (2009)] published Tue Nov 17, 2009.
Growing heterogeneous tumors in silico
Jana Gevertz and S. Torquato
An in silico tool that can be utilized in the clinic to predict neoplastic progression and propose individualized treatment strategies is the holy grail of computational tumor modeling. Building such a tool requires the development and successful integration of a number of biophysical and mathematic ... [Phys. Rev. E 80, 051910 (2009)] published Mon Nov 16, 2009.
Computer-assisted extraction of intracranial aneurysms on 3D rotational angiograms for computational fluid dynamics modeling
Herng-Hua Chang, Gary R. Duckwiler, Daniel J. Valentino, and Woei Chyn Chu
Erratum: Symmetry, Multistability, and Long-Range Interactions in Brain Development [Phys. Rev. Lett. 95, 208701 (2005)]
Fred Wolf
Abstract not available. [Phys. Rev. Lett. 103, 209902 (2009)] published Fri Nov 13, 2009.
Formation and growth of lipofuscin in the retinal pigment epithelium cells
K. I. Mazzitello, C. M. Arizmendi, F. Family, and H. E. Grossniklaus
The kinetics of lipofuscin growth in diseased retinal pigment epithelium cells is investigated using Monte Carlo simulations and scaling theory on a cluster aggregation model. The model captures the essential physics of lipofuscin growth in the cells. A remarkable feature is that small particles may ... [Phys. Rev. E 80, 051908 (2009)] published Thu Nov 12, 2009.
Lubrication of the Human Ankle Joint in Walking
Miroslav HlavaCek
Human ankle joint lubrication in walking is analyzed. A biphasic mixture model is considered for articular cartilage (ideal interstitial fluid and elastic porous matrix that is transversely isotropic and inhomogeneous throughout its thickness). Synovial fluid is considered Newtonian. Its viscosity i ... [J. Tribol. 132, 011201 (2009)] published Wed Nov 11, 2009.
Non-contact detection of myocardium's mechanical activity by ultrawideband RF-radar and interpretation applying electrocardiography
F. Thiel, D. Kreiseler, and F. Seifert
Electromagnetic waves can propagate through the body and are reflected at interfaces between materials with different dielectric properties. Therefore the reason for using ultrawideband (UWB) radar for probing the human body in the frequency range from 100 MHz up to 10 GHz is obvious and suggests an ... [Rev. Sci. Instrum. 80, 114302 (2009)] published Tue Nov 10, 2009.
A Study on Construction Three-Dimensional Nonlinear Finite Element Model and Stress Distribution Analysis of Anterior Cruciate Ligament
Feng Xie, Liu Yang, Lin Guo, Zhi-jun Wang, and Gang Dai
To establish a finite element model that reflects the geometric characteristics of the normal anterior cruciate ligament (ACL), explore the approaches to model knee joint ligaments and analyze the mechanics of the model. A healthy knee joint specimen was subjected to three-dimensional laser scanning ... [J. Biomech. Eng. 131, 121007 (2009)] published Tue Nov 10, 2009.
Dynamical activities of primary somatosensory cortices studied by magnetoencephalography
Kuniharu Kishida
A blind identification method of transfer functions in feedback systems is introduced for examination of dynamical activities of cortices by magnetoencephalography study. Somatosensory activities are examined in 5 Hz periodical median nerve stimulus. In the present paper, we will try two careful pre ... [Phys. Rev. E 80, 051906 (2009)] published Fri Nov 6, 2009.
Ground Reaction Forces and Lower Extremity Kinematics When Running With Suppressed Arm Swing
Ross H. Miller, Graham E. Caldwell, Richard E. A. Van Emmerik, Brian R. Umberger, and Joseph Hamill
The role of arm swing in running has been minimally described, and the contributions of arm motion to lower extremity joint kinematics and external force generation are unknown. These contributions may have implications in the design of musculoskeletal models for computer simulations of running, sin ... [J. Biomech. Eng. 131, 124502 (2009)] published Wed Nov 4, 2009.
Differences in Aortic Arch Geometry, Hemodynamics, and Plaque Patterns Between C57BL/6 and 129/SvEv Mice
Hui Zhu, Ji Zhang, Jessica Shih, Federico Lopez-Bertoni, John R. Hagaman et al.
Atherosclerotic plaques are distributed differently in the aortic arches of C57BL/6 (B6) and 129/SvEv (129) apolipoprotein E (apoE)-deficient mice. It is now recognized that hemodynamic wall shear stress (WSS) plays an important role in the localization of atherosclerotic development. Since the bloo ... [J. Biomech. Eng. 131, 121005 (2009)] published Wed Nov 4, 2009.
Continuous Age-Structured Model for Bovine Tuberculosis in African buffalo
R. Anguelov and H. Kojouharov
The paper deals with a model of the spread of bovine tuberculosis in the buffalo population in the Kruger National Park in South Africa. The model uses continuous age structure and it is formulated in terms of partial differential equations using eight epidemiological classes (compartments). More pr ... [AIP Conf. Proc. 1186, 443 (2009)] published Fri Oct 30, 2009.
Hemodynamic and electrophysiological signals of conflict processing in the Chinese-character Stroop task: a simultaneous near-infrared spectroscopy and event-related potential study
Jiahuan Zhai, Ting Li, Zhongxing Zhang, and Hui Gong
A dual-modality method combining continuous-wave near-infrared spectroscopy (NIRS) and event-related potentials (ERPs) was developed for the Chinese-character color-word Stroop task, which included congruent, incongruent, and neutral stimuli. Sixteen native Chinese speakers participated in this stud ... [J. Biomed. Opt. 14, 054022 (2009)] published Thu Oct 29, 2009.
Simple model for bursting dynamics of neurons
Anandamohan Ghosh, Dipanjan Roy, and Viktor K. Jirsa
Neuronal cells in isolation or as an assembly exhibit bursting behavior on two different time scales. We introduce a simple one-dimensional model which requires only one phase variable to describe the phenomenon of parabolic bursting. The analysis in the continuum limit reveals that for any unimodal ... [Phys. Rev. E 80, 041930 (2009)] published Thu Oct 29, 2009.
The Theoretical Foundation for Artery Buckling Under Internal Pressure
Hai-Chao Han
The stability of blood vessels under the lumen blood pressure is essential to the maintenance of normal arterial function. Buckling equations have been established recently for linear and nonlinear elastic artery models with assumed sinusoidal mode shapes. However, the theoretical base for the assum ... [J. Biomech. Eng. 131, 124501 (2009)] published Thu Oct 29, 2009.
Human Foot Placement and Balance in the Sagittal Plane
Matthew Millard, Derek Wight, John McPhee, Eric Kubica, and David Wang
Foot placement has long been recognized as the primary mechanism that humans use to restore balance. Many biomechanists have examined where humans place their feet during gait, perturbations, and athletic events. Roboticists have also used foot placement as a means of control but with limited succes ... [J. Biomech. Eng. 131, 121001 (2009)] published Thu Oct 29, 2009.
Increase in Opening Angle in Hypertension Off-Loads the Intimal Stress: A Simulation Study
Chong Wang and Ghassan S. Kassab
The stress distribution in the vessel wall has important bearing on vascular function including intima, media, and adventitia. The residual strain in the vessel wall has been thought to largely normalize the transmural stress distribution with slightly higher values at the intima. In hypertension, t ... [J. Biomech. Eng. 131, 114502 (2009)] published Mon Oct 26, 2009.
A New Observation on the Stress Distribution in the Coronary Artery Wall
Chong Wang, Xiaomei Guo, and Ghassan S. Kassab
The stress distribution in the vessel wall has an important bearing on vascular function in health and disease. We studied the relationship between the transmural stress distribution and the opening angle (OA) to determine the stress gradient. The simulation of wall stress was based on transmural me ... [J. Biomech. Eng. 131, 111011 (2009)] published Mon Oct 26, 2009.