Abstract：
:To evaluate the efficacy of implanting a tilting disc aortic valve prosthesis in an angulated (wedged) supra-annular position, an in vitro experimental study was performed. The aortic valve prosthesis was mounted in an axi-symmetric valve chamber in a wedged position and incorporated in a mock circulatory system. Measurements were obtained on the transvalvular pressure gradient, percent regurgitation as well as velocity profiles and turbulent normal stresses distal to the valve. Our results showed that there was no significant reduction in the pressure gradient in mounting a larger sized valve in the wedged supra-annular position. On the other hand, the percent regurgitation increased with increase in heart rate and wedge angle. The valve failed to function properly above 110 beats min-1 at any wedge angle with the normal flow rate. The velocity profiles also showed significant changes with an increase in the turbulent normal stress with increase in wedge angle. Hence our study suggests that implanting the tilting disc prosthesis in a wedged supra-annular position in the aorta is not advisable.
journal_name
J Biomechjournal_title
Journal of biomechanicsauthors
Chandran KB,Fatemi R,Hiratzka LF,Harris Cdoi
10.1016/0021-9290(86)90150-8subject
Has Abstractpub_date
1986-01-01 00:00:00pages
181-6issue
3eissn
0021-9290issn
1873-2380pii
0021-9290(86)90150-8journal_volume
19pub_type
杂志文章abstract：:A series of 33 human femoral bones have been subjected to a four point bending test at high strain rates. Two different failure modes were recognized. A Y shaped fracture at the middle region induced by a pure bending moment yielded a zone of non-linearity at the load vs deformation curve and a higher bending force, m...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(86)90021-7
更新日期：1986-01-01 00:00:00
abstract：:Knowledge of accurate in-vivo 6 degree-of-freedom (6-DOF) kinematics of total hip arthroplasty (THA) during daily activities is critical for improvement of longevity of the components. Previous studies assessed in-vivo THA kinematics using skin marker-based motion analysis. However, skin markers are prone to move with...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2014.03.012
更新日期：2014-05-07 00:00:00
abstract：:The role of pulsatile unloading in hemodynamic changes in intraventricular flow and ventricular wall stress remains unknown. In this study, a finite element model of the left ventricle (LV) is proposed to calculate the mechanical response. The constitutive model of the LV is composed of a quasi-incompressible transver...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2019.109425
更新日期：2020-04-16 00:00:00
abstract：:The purpose of this study was to apply the Floating Axis analysis technique to the elbow joint, and to verify its ability to quantify clinically relevant radiohumeral translation in vitro using an electromagnetic tracking device. Of particular interest was the ability to quantify changes in anterior-posterior radial h...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(03)00103-9
更新日期：2003-08-01 00:00:00
abstract：:The purpose of this study was to find the optimal values of design parameters for a bicycle-rider system (crank length, pelvic inclination, seat height, and rate of crank rotation) which maximize the power output from muscles of the human lower limb during bicycling. The human lower limb was modelled as a planar syste...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(90)90322-t
更新日期：1990-01-01 00:00:00
abstract：:The study analyses the two-dimensional distribution of surface mechanomyographic (MMG) signal generated by the activation of single motor units located in three transverse positions in the tibialis anterior muscle. In 12 healthy volunteers, surface MMG signals were recorded from the tibialis anterior muscle with a 3 x...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2008.07.007
更新日期：2008-09-18 00:00:00
abstract：:The paper defines the term coordination interval (CI), suggesting that it should replace the term electromechanical delay (EMD), if this parameter is determined in vivo for a muscle functioning in a biomechanical system with considerable mobility, but not in a kinematic pair with one degree of rotational freedom (DOF)...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(94)90211-9
更新日期：1994-02-01 00:00:00
abstract：:This work is a novel attempt to incorporate computational fluid dynamics (CFD) techniques in the analysis of hemodynamic parameters of Moyamoya disease (MMD). Highly prevalent in Asian countries, MMD is characterised by progressive occlusion of the intracranial Internal Carotid Arteries (ICA). We intend to identify a ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2014.11.029
更新日期：2015-01-21 00:00:00
abstract：:Hamstring muscle strain injury is one of the most common injuries in sports involving sprinting and kicking. Studies examining hamstring kinematics and activations are rich for sprinting but lacking for kicking. The purpose of this study was to examine kinematics and activations of hamstring muscles in instep and cut-...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2019.109482
更新日期：2020-01-23 00:00:00
abstract：:The swimming process by which mammal spermatozoa progress towards an egg within the reproductive organs is important in achieving successful internal fertilization. The viscosity of oviductal mucus is more than two orders of magnitude greater than that of water, and oviductal mucus also has non-Newtonian properties. I...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.08.005
更新日期：2015-09-18 00:00:00
abstract：:The study was designed to examine the effects of partial fatigue on specific mechanical parameters which characterise human tendons in vitro. Specimens prepared from 12 intact Extensor digitorum longus tendons of the foot were subjected to partial fatigue, equivalent to 25% of the median fatigue life, by a cyclic squa...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(01)00177-4
更新日期：2002-03-01 00:00:00
abstract：:This study looks at pulsatile blood flow through four different right coronary arteries, which have been reconstructed from biplane angiograms. A non-Newtonian blood model (the Generalised Power Law), as well as the usual Newtonian model of blood viscosity, is used to study the wall shear stress in each of these arter...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2005.01.034
更新日期：2006-01-01 00:00:00
abstract：:Pedicle-screw-based motion preservation systems are often used to support a slightly degenerated disc. Such implants are intended to reduce intradiscal pressure and facet joints forces, while having a minimal effect on the motion patterns. In a probabilistic finite element study with subsequent sensitivity analysis, t...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2010.07.018
更新日期：2010-11-16 00:00:00
abstract：:This paper deals with the impact force during foot-ground impact activities such as the running. A previously developed model is used for this study. The model is a lumped-parameter one consisting of four masses connected to each other via linear springs and viscous dampers. A shoe-specific nonlinear function is used ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2006.09.016
更新日期：2007-01-01 00:00:00
abstract：:Histological investigation along with finite element analysis of arterial wall/atherosclerotic plaque geometries indicates the paradoxical result that ruptures often occur at sites with predicted stresses of half the plaque cap strength. Recent experiments have revealed calcified cells within the cap suggesting that t...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2010.06.012
更新日期：2010-10-19 00:00:00
abstract：:Osteoarthritis (OA) is typically diagnosed in humans in its final stage when joint movement becomes painful. Clinical information about the onset and the mechanisms triggering the degenerative responses are virtually non-existent. However, research on animal models of experimental OA shows that joint adaptations assoc...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(97)00119-x
更新日期：1998-03-01 00:00:00
abstract：:Energy conservation in swimming is formulated in terms of four functions of the swim speed v: the consumed power K, the mechanical power P used for horizontal propulsion, the remaining expended mechanical power N, and the thermal power loss H. K is well-known (from VO2) and P = FDv, where the drag force FD is not know...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(94)00143-r
更新日期：1995-08-01 00:00:00
abstract：:Tendons are elastic structures that connect muscle to the skeletal system and transmit force relative to the amount of stretch they experience. The mechanical properties of human tendons are difficult to measure non-invasively, so generic values are often assumed in musculoskeletal models to represent all subjects. We...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.06.009
更新日期：2015-09-18 00:00:00
abstract：:Cellular alignment studies have shown that cell orientation has a large effect on the expression and behavior of cells. Cyclic strain and substrate microtopography have each been shown to regulate cellular alignment. This study examined the combined effects of these two stimuli on the alignment of bovine vascular smoo...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2007.11.027
更新日期：2008-01-01 00:00:00
abstract：:Valgus moments on the knee joint during single-leg landing have been suggested as a risk factor for anterior cruciate ligament (ACL) injury. The purpose of this study was to test the influence of isolated valgus moment on ACL strain during single-leg landing. Physiologic levels of valgus moments from an in vivo study ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2008.10.031
更新日期：2009-02-09 00:00:00
abstract：:In human walking, the center of mass motion is similar to an inverted pendulum. Viewing double support as a transition from one inverted pendulum to the next, we hypothesized that the leading leg performs negative work to redirect the center of mass velocity, while simultaneously, the trailing leg performs positive wo...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(01)00169-5
更新日期：2002-01-01 00:00:00
abstract：:We evaluated whether the use of cartilage thickness measurement would improve the ability of the arthroscopic indentation technique to estimate the intrinsic stiffness of articular cartilage. First, cartilage thickness and ultrasound reflection from the surface of bovine humeral head were registered in situ using a hi...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(00)00189-5
更新日期：2001-02-01 00:00:00
abstract：:The hypothesis that thrombus can be induced by localized shear stresses/rates, such as in the bent/stretched microvessels, was tested both experimentally and computationally. Our newly designed in vivo experiments were performed on the microvessels (post-capillary venules, 20-50 microm diameter) of rat mesentery. Thes...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2008.06.013
更新日期：2008-08-28 00:00:00
abstract：PURPOSE:Approximately 348,000 ventral hernia repairs are performed annually in the United States and the incisional hernia recurrence rate is approximately 20% as a result of suture and mesh device failure. Device failure is related to changes at the suture/tissue interface that leads to acute or chronic suture pull-th...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.01.022
更新日期：2018-04-11 00:00:00
abstract：:The reference point indentation (RPI) method is a microindentation technique involving successive indentation cycles. We employed RPI to measure average stiffness (Ave US), indentation distance increase (IDI), total indentation distance (TID), average energy dissipated (Ave ED), and creep indentation distance (CID) of...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2013.04.003
更新日期：2013-06-21 00:00:00
abstract：:For the purpose of detecting early aberrations of gait in rheumatoid arthritis 17 women suffering from that disease were examined. They were all under 50 years of age and had an essentially normal range of motility in the hips, knees and ankles. Eleven healthy women walking at voluntary speed and 6 healthy women walki...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(88)90237-0
更新日期：1988-01-01 00:00:00
abstract：:A biomechanical model of the human thorax was constructed to investigate how asymmetric growth of the thorax might initiate spinal lateral curvature and axial rotation as seen in scoliosis deformities. Geometric data specifying nodal points of the model were taken from stereo-radiographs of an adolescent subject. An i...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(90)90051-4
更新日期：1990-01-01 00:00:00
abstract：:Seated ergometer pedaling is a motor task ideal for studying basic mechanisms of human bipedal coordination because, in contrast to standing and walking, fewer degrees of freedom are being controlled and upright balance is not a factor. As a step toward understanding how individual muscles coordinate pedaling, we inve...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(95)00011-9
更新日期：1996-01-01 00:00:00
abstract：:Implants of microporous β-tricalcium phosphate (β-TCP) were developed for primarily stable supply of bone defects. A consistent stability over the healing period should be retained in sheep. β-TCP cylindrical shaped implants, with 7 mm diameter, 25 mm length, medium pore diameter 5 μm and 40% porosity were developed. ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.01.040
更新日期：2015-04-13 00:00:00
abstract：:Anterior cruciate ligament (ACL) volume and T2∗ relaxation times from magnetic resonance (MR) images have been previously shown to predict the structural properties of healing ligaments. We investigated whether MR imaging scan resolution and condition (in vivo, in situ, or ex vivo) affected ACL volume and T2∗ relaxati...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2017.03.010
更新日期：2017-05-03 00:00:00
