The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Eric Y Chang - One of the best experts on this subject based on the ideXlab platform.
-
ultrashort echo time t2 values decrease in tendons with application of static Tensile Loads
Journal of Biomechanics, 2017Co-Authors: Saeed Jerban, Amin Nazaran, Xin Cheng, Michael Carl, Nikolaus M Szeverenyi, Eric Y ChangAbstract:In early stages of tendon disease, mechanical properties may become altered prior to changes in morphological anatomy. Ultrashort echo time (UTE) magnetic resonance imaging (MRI) can be used to directly detect signal from tissues with very short T2 values, including unique viscoelastic tissues such as tendons. The purpose of this study was to use UTE sequences to measure T2∗, T1 and magnetization transfer ratio (MTR) variations of tendon samples under static Tensile Loads. Six human peroneal tendons were imaged before and under static loading using UTE sequences on a clinical 3T MRI scanner. Tendons were divided into two static Tensile loading groups: group A that underwent one-step loading (15N) and group B that underwent two-step loading (15 and 30N). The T2∗, T1 and MTR variations were investigated in two selected section regions of interest (ROIs), including whole and core sections. Mean T2∗ values for the first step of loading (groups A and B) in both whole section and core section ROIs were significantly decreased by 13±7% (P=0.028) and 16±5% (P=0.017), respectively. For the second loading step (group B), there was a consistent, but non-significant reduction in T2∗ value by 9±2% (P=0.059) and 7±5% (P=0.121) for whole and core sections, respectively. Mean T1 did not show any consistent changes for either loading steps (P>0.05). Mean MTR increased slightly, but not significantly for both loading steps (P>0.05). Significant differences were found only in T2∗ values of tendons by static Tensile load application. Therefore, T2∗ monitoring during loading is suggested for quantitative investigation of the tendons biomechanics.
Xin Cheng - One of the best experts on this subject based on the ideXlab platform.
-
ultrashort echo time t2 values decrease in tendons with application of static Tensile Loads
Journal of Biomechanics, 2017Co-Authors: Saeed Jerban, Amin Nazaran, Xin Cheng, Michael Carl, Nikolaus M Szeverenyi, Eric Y ChangAbstract:In early stages of tendon disease, mechanical properties may become altered prior to changes in morphological anatomy. Ultrashort echo time (UTE) magnetic resonance imaging (MRI) can be used to directly detect signal from tissues with very short T2 values, including unique viscoelastic tissues such as tendons. The purpose of this study was to use UTE sequences to measure T2∗, T1 and magnetization transfer ratio (MTR) variations of tendon samples under static Tensile Loads. Six human peroneal tendons were imaged before and under static loading using UTE sequences on a clinical 3T MRI scanner. Tendons were divided into two static Tensile loading groups: group A that underwent one-step loading (15N) and group B that underwent two-step loading (15 and 30N). The T2∗, T1 and MTR variations were investigated in two selected section regions of interest (ROIs), including whole and core sections. Mean T2∗ values for the first step of loading (groups A and B) in both whole section and core section ROIs were significantly decreased by 13±7% (P=0.028) and 16±5% (P=0.017), respectively. For the second loading step (group B), there was a consistent, but non-significant reduction in T2∗ value by 9±2% (P=0.059) and 7±5% (P=0.121) for whole and core sections, respectively. Mean T1 did not show any consistent changes for either loading steps (P>0.05). Mean MTR increased slightly, but not significantly for both loading steps (P>0.05). Significant differences were found only in T2∗ values of tendons by static Tensile load application. Therefore, T2∗ monitoring during loading is suggested for quantitative investigation of the tendons biomechanics.
Kyongho Chang - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis of residual stresses in welds of similar or dissimilar steel weldments under superimposed Tensile Loads
Computational Materials Science, 2007Co-Authors: Chinhyung Lee, Kyongho ChangAbstract:Abstract This paper presented the characteristics of residual stresses in welds of similar or dissimilar steel weldments by carrying out three-dimensional (3-D) thermal elastic–plastic finite element (FE) analyses. Moreover, residual stress behavior in welds of the weldments under superimposed Tensile Loads was further investigated. The materials used in this investigation were SM400, SM490, SM520 and SM570, widely used structural steels in welded structure. Results show that the maximum longitudinal residual stresses in welds of the similar steel weldments increase with increasing yield stress of the steel welded (SM400
Toshimi Hirata - One of the best experts on this subject based on the ideXlab platform.
-
Dilatometry of wood: Part I. Longitudinal dilatometry of wood untreated and treated with ammonium phosphate
Journal of Analytical and Applied Pyrolysis, 1992Co-Authors: Toshimi HirataAbstract:Abstract In order to obtain information about the dimensional changes of wood at high temperatures, dilatometry of untreated and ammonium phosphate-treated Japanese cedar wood (25×5.0×0.2 mm) under constant Tensile Loads was carried out with uniform heating rates in a vacuum. The untreated sample first underwent elongation, due probably because of scission of linkages in the lignin network and then shrinkage due to bond formation in cellulose, such as cross-linking and grafting. With high heating rates or large Loads the shrinkage was followed by another stage of elongation and then shrinkage which could be ascribed to the chain scission of cellulose accelerated by the increase in Tensile stress and to bond formation in cellulose. The dimensional changes of ammonium phosphate-treated wood were first elongation due to the scission of cellulose and then shrinkage due to bond formation in cellulose. With large Loads, the elongation stage progressed through two steps which were ascribable to the scission of linkages in lignin and cellulose, respectively. The activation energies for the dimensional changes were obtained and the effects of Tensile Loads on them are discussed. Also the activation energies of weight loss are determined.
Saeed Jerban - One of the best experts on this subject based on the ideXlab platform.
-
ultrashort echo time t2 values decrease in tendons with application of static Tensile Loads
Journal of Biomechanics, 2017Co-Authors: Saeed Jerban, Amin Nazaran, Xin Cheng, Michael Carl, Nikolaus M Szeverenyi, Eric Y ChangAbstract:In early stages of tendon disease, mechanical properties may become altered prior to changes in morphological anatomy. Ultrashort echo time (UTE) magnetic resonance imaging (MRI) can be used to directly detect signal from tissues with very short T2 values, including unique viscoelastic tissues such as tendons. The purpose of this study was to use UTE sequences to measure T2∗, T1 and magnetization transfer ratio (MTR) variations of tendon samples under static Tensile Loads. Six human peroneal tendons were imaged before and under static loading using UTE sequences on a clinical 3T MRI scanner. Tendons were divided into two static Tensile loading groups: group A that underwent one-step loading (15N) and group B that underwent two-step loading (15 and 30N). The T2∗, T1 and MTR variations were investigated in two selected section regions of interest (ROIs), including whole and core sections. Mean T2∗ values for the first step of loading (groups A and B) in both whole section and core section ROIs were significantly decreased by 13±7% (P=0.028) and 16±5% (P=0.017), respectively. For the second loading step (group B), there was a consistent, but non-significant reduction in T2∗ value by 9±2% (P=0.059) and 7±5% (P=0.121) for whole and core sections, respectively. Mean T1 did not show any consistent changes for either loading steps (P>0.05). Mean MTR increased slightly, but not significantly for both loading steps (P>0.05). Significant differences were found only in T2∗ values of tendons by static Tensile load application. Therefore, T2∗ monitoring during loading is suggested for quantitative investigation of the tendons biomechanics.
