We analyze the coherent dynamics of optically excited alkenes in a fully correlated 3d tight-binding model with extended Hubbard interactions. The scenario that emerges is that the steric repulsive interactions are the driving force behind ultrafast cis-trans photoisomerizations. This resolves the apparent discrepancy between values for the torsional stiffness obtained from band-structure poten...

Left ventricular systolic torsion and diastolic recoil were quantified in 12 human cardiac transplant recipients with surgically implanted intramyocardial markers with the use of computer-aided analysis of biplane cineradiographic images. Measurements were performed between 6 and 16 weeks after surgery and related to the presence or absence of rejection as determined by cardiac biopsy. Torsiona...

the cadaver spine motion segment behavior under torsional load was evaluated with the disc intact, with partial anterior discectomy and with spacer insertion. the results of this study explain how anterior lumbar discectomy and interbody fusion (alif) affects the torsional stability of the motion segment. the pseudarthrosis rate of the anterior lumbar discectomy and interbody fusion (alif) is k...

Ions regulate the assembly and mechanical properties of actin filaments. Recent work using structural bioinformatics and site-specific mutagenesis favors the existence of two discrete and specific divalent cation binding sites on actin filaments, positioned in the long axis between actin subunits. Cation binding at one site drives polymerization, while the other modulates filament stiffness and...

Endosseous cementless implants are widely used in orthopaedic, maxillofacial and oral surgery. However, failures are still observed and remain difficult to anticipate as remodelling phenomena at the bone-implant interface are poorly understood. The assessment of the biomechanical strength of the bone-implant interface may improve the understanding of the osseointegration process. An experimenta...

Nepal is situated in an area with considerable seismic activity. It important to choose structural systems that can withstand the lateral loads. In a dual system of reinforced concrete structures, placement shear walls optimally increases stiffness buildings. The rigidity RC buildings may be improved by strategically placing lift core walls. Buildings would more useful if they had easy access e...

Expert insights into the time-domain dynamic behavior of heavy-duty gearboxes form foundations design evaluation and improvement. However, in existing lateral–torsional coupling (LTC) modeling method for that is normally used frequency-domain behavior, meshing forces are modeled as spring dampers with fixed acting points on gears to simulate only transient LTC effect, thus steady state characte...

Background Arterial stiffness increases pressure load to the left ventricle (LV), leading to LV hypertrophy and subendocardial ischemia. Neurohormones stimulate myocardial fibrosis and LV dysfunction. We aimed to explore the associations of arterial stiffness and plasma aldosterone with multi-directional, layer-specific LV, and left atrial (LA) mechanical function in hypertensive patients. Me...

The objectives of this study were to obtain linearized stiffness matrices, and assess the linearity and hysteresis of the motion segments of the human lumbar spine under physiological conditions of axial preload and fluid environment. Also, the stiffness matrices were expressed in the form of an 'equivalent' structure that would give insights into the structural behavior of the spine. Mechanica...

In order to achieve predictable handling of a race car, local mounts connecting suspension components to the chassis should be sufficiently rigid to minimize unwanted local deflection which may adversely affect suspension geometry. In this work, the effects of local chassis flexibility of the spring perch on roll stiffness, tire camber change, and steer angle change are determined from a finite...