نتایج جستجو برای: stiffness modulus

تعداد نتایج: 66509  

Journal: :the journal of tehran university heart center 0
tavvos rahmani-cherati medical physics department, tarbiat modares university, tehran, iran. manijhe mokhtari-dizaji medical physics department, tarbiat modares university, tehran, iran. masome gity medical imaging center, imam khomeini hospital, medical sciences / university of tehran, tehran, ira

background: common carotid arterial stiffness can be assessed during carotid arterial ultrasonography, but its association with brachial stiffness, a well-defined cardiovascular risk factor, has not been clarified. the aim of this study was to examine the relationship between common carotid artery and brachial artery stiffness. methods: the static pressure-strain elastic modulus of the common c...

Abolfazl Hasani Iman Salehi Hikouei Ziba Shirkhani Kelagari

The Stiffness modulus is one of the necessary inputs in mechanistic-empirical pavement design and Quality Assurance/Quality Control (Q Q A C ) of pavement layers construction. The use of Portable Falling Weight Deflectometer (PFWD) for measuring the stiffness modulus of unbound pavement layers is increasing worldwide. The modulus can also be...

Journal: :Circulation 2010
Rajiv R Chaturvedi Todd Herron Robert Simmons Darryl Shore Pankaj Kumar Babulal Sethia Felix Chua Efstathios Vassiliadis Jonathan C Kentish

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 ...

Journal: :Journal of biomechanics 2015
Ondrej Holub Alejandro López Vishal Borse Håkan Engqvist Nik Kapur Richard M Hall Cecilia Persson

The high stiffness of bone cements used in vertebroplasty has been hypothesised to contribute to the propensity of adjacent vertebral fractures after treatment. Therefore, new low-modulus cements have been developed; however, there are currently no studies assessing the biomechanical aspects of vertebroplasty with these cements in an ex vivo non-prophylactic model. In this study, we induced wed...

Journal: :The Journal of clinical investigation 1972
J S Forrester G Diamond W W Parmley H J Swan

The left ventricular (LV) pressure-volume (P-V) relationship is a resultant of several determinants, including initial ventricular volume, geometry, and wall stiffness. A quantitative index of one of these determinants, LV wall stiffness, was developed from a mathematical analysis of the isolated P-V relationship. Since this relationship was exponential, stiffness (dP/dV) could be expressed by ...

2013
A. S. Shahsavari

The elastic modulus of two-dimensional random fibre networks is determined for structures in which, the degree of cross-linking is varied. The relationship between the network parameters – fibre axial and bending stiffness, fibre density and degree of cross-linking – and the overall elastic modulus is discussed and presented in terms of a master curve. It is shown that master curves for sparsel...

2010
Rajiv R. Chaturvedi Felix Chua Jonathan C. Kentish

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 wer...

2010
Jeremy Bercoff

2 One of the key medical methods for detection and characterization of pathologies is the assessment of tissue stiffness by palpation. The importance of clinical assessment of tissue stiffness has been known since ancient times: In Pharonic Egypt, more than 5000 years ago, physicians practiced palpation of body parts to determine tissue stiffness. They knew that a hard mass within an organ was ...

2016
Lingjing Zhu Yixing Liu Zhenbo Liu

The crystallinity and acoustic-vibration parameters of Picea jezoensis, including specific Young’s modulus (E/ρ),coefficient of sound-radiation resistance (R), sound resistance (ω), and the ratio of Young’s modulus to the dynamic stiffness modulus (E/G), before and after heat treatment were measured and characterized. Conditions for the heat treatment included N2 as the protection gas and tempe...

Journal: :Magnetic resonance in medicine 2005
Stacie I Ringleb Qingshan Chen David S Lake Armando Manduca Richard L Ehman Kai-Nan An

Magnetic resonance elastography (MRE), a phase contrast MRI technique, images the propagation of applied mechanical waves in tissue, allowing shear stiffness to be quantified in vivo. This MRE technique has been validated with static mechanical compression tests. Dynamic mechanical analysis (DMA) may be a more appropriate comparison to MRE because it directly measures the shear modulus dynamica...

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