OBJECTIVES Post-transplantation hypertension is prevalent and is associated with increased cardiovascular morbidity and subsequent graft dysfunction. The present study aimed to identify the factors associated with arterial stiffness as measured by the ambulatory arterial stiffness index. METHODS The current study used a prospective, observational, analytical design to evaluate a group of adul...

We believe that the lateral exploration of surfaces with varying stiffness, stiffness maps, using computer generated haptics is an underestimated and important procedure with impact in many application areas. Feeling the change of stiffness while sweeping the haptic probe over a surface can potentially give an understanding of the spatial distribution of this stiffness, however current algorith...

We tested an innovative method to estimate joint stiffness and damping during multijoint unfettered arm movements. The technique employs impulsive perturbations and a time-frequency analysis to estimate the arm's mechanical properties along a reaching trajectory. Each single impulsive perturbation provides a continuous estimation on a single-reach basis, making our method ideal to investigate m...

Using numerical integration in the formulation of the finite-element geometric stiffness matrix and placing movable nodes at integration points causes the geometric stiffness matrix to become lumped or diagonal. The consistent geometric stiffness matrix which is a non-diagonal matrix, is normally used in the finite-element eigenvalue buckling problem. Altering the method to deliver a diagonal (...

Food intake increases liver stiffness, but it is believed that liver stiffness returns to baseline two hours after a meal. The aim of this study was to investigate the impact of different sized meals on liver stiffness. Liver and spleen stiffness was measured with transient elastography (TE) and real-time 2-dimensional shear wave elastography (2D-SWE). Patients ingested a 625 kcal and a 1250 kc...

Humans produce speech by controlling a complex biomechanical apparatus to achieve desired speech sounds. We show here that kinematic variability in speech may be influenced by patterns of jaw stiffness. A robotic device was used to deliver mechanical perturbations to the jaw to quantify its stiffness in the mid-sagittal plane. Measured jaw stiffness was anisotropic. Stiffness was greatest along...

A methodology for tuning the stiffness of machine tool supports is described based on a stiffness model using the contact stiffness approach. Using this model, the mathematical relationship between the load of the support and its stiffness is established. The relationship is separated into three regions. When the total stiffness of all supports is maximized, the load must be tuned so that the s...

− Studies of arm movement have suggested that the control of stiffness may be important for maintaining stability during interactions with the environment. Here we have examined the voluntary control of stiffness in the human jaw. The goal was to determine whether changes in jaw stiffness might be used to maintain jaw position in the face potentially destabilizing mechanical loads. A series of ...

BACKGROUND When humans are faced with an unstable task, two different stabilization mechanisms are possible: a high-stiffness strategy, based on the inherent elastic properties of muscles/tools/manipulated objects, or a low-stiffness strategy, based on an explicit positional feedback mechanism. Specific constraints related to the dynamics of the task and/or the neuromuscular system often force ...

BACKGROUND In ventricular dilatation or hypertrophy, an elevated end-diastolic pressure is often assumed to be secondary to increased myocardial stiffness, but stiffness is rarely measured in vivo because of difficulty. We measured in vitro passive stiffness of volume- or pressure-overloaded myocardium mainly from congenital heart disease. METHODS AND RESULTS Endocardial ventricular biopsies ...