OBJECTIVE Previous studies have demonstrated a prognostic role of large artery stiffness in hypertensive subjects and increased stiffness in subjects with coronary artery disease. Although plasma cholesterol is an established risk factor for cardiovascular disease, its relationship with large artery properties in a hypertensive population is unclear. METHODS AND RESULTS Plasma cholesterol and...

Pediatric anthropomorphic test devices (ATDs) do not contain instrumentation below the knee, making it difficult to directly measure forces applied to the leg during impact. The goal of this study was to evaluate the anthropometric characteristics and stiffness response of the pediatric ankle in order to gain valuable data for the development of a more biofidelic ATD ankle. Forty-two children b...

A simple optical tweezers design is proposed to manipulate particles in the axial direction and estimate particle position with nanometer sensitivity. Balb3T3 cell is probed using two different-sized particles, and the localized cell stiffness is evaluated using Hertz model. A series of experiments are performed to obtain the necessary parameters for the cell stiffness computation: particle dis...

Although microtubules are involved in various pathological conditions of the heart including hypertrophy and congestive heart failure, the mechanical role of microtubules in cardiomyocytes under such conditions is not well understood. In the present study, we measured multiple aspects of the mechanical properties of single cardiomyocytes, including tensile stiffness, transverse (indentation) st...

In recent years, ultrasonic methods have been developed that can be used to measure the mechanical stiffness of materials.1-5 In one such method, the velocity of a flexural plate wave, the lowest order antisymmetric Lamb mode, is measured as a function of frequency. Lamb waves arise from a coupling at the free boundaries between the shear waves and compressional waves in a plate structure.6 The...

Passive stiffness characteristics of isolated cardiac myocytes, papillary muscles, and aortic strips from male Holtzman rats fed a copper-deficient diet for approximately 5 wk were compared with those of rats fed a copper-adequate diet to determine whether alterations in these characteristics might accompany the well-documented cardiac hypertrophy and high incidence of ventricular rupture chara...

Reversible changes in lung microstructure accompany lung inflammation, although alterations in tissue micromechanics and their impact on inflammation remain unknown. This study investigated changes in extracellular matrix (ECM) remodeling and tissue stiffness in a model of LPS-induced inflammation and examined the role of lipoxin analog 15-epi-lipoxin A4 (eLXA4) in the reduction of stiffness-de...

Background: The aim of the study was to investigate the use of quantitative ultrasound (QUS) in the young (20-25years) Saudi females to obtain stiffness index values related to bone quality. Method & Findings: In 101 young females recruited, QUS measurements were performed in the calcaneus region. 33% and 3% had osteopenia and osteoporosis in the calcaneus respectively, stiffness index values =...

Holographic optical tweezers is a widely used technique to manipulate the individual positions of optically trapped micron-sized particles in a sample. The trap positions are changed by updating the holographic image displayed on a spatial light modulator. The updating process takes a finite time, resulting in a temporary decrease of the intensity, and thus the stiffness, of the optical trap. W...

This paper describes the experimental studies of vertical dynamic stiffness of single piles subjected to small amplitude of vibrations with constant dynamic load. The test results were correlated with the static load test results that had been carried out on the same piles. The ratio of dynamic to static stiffness mainly falls between 1.2-1.4. The dynamic stiffness measurements were compared wi...