Viscoelastic properties of pressure overload hypertrophied myocardium: effect of serine protease treatment

2002 ◽  
Vol 282 (6) ◽  
pp. H2324-H2335 ◽  
Author(s):  
Jason D. Stroud ◽  
Catalin F. Baicu ◽  
Mary A. Barnes ◽  
Francis G. Spinale ◽  
Michael R. Zile
Keyword(s):  
Serine Protease ◽  
Viscoelastic Properties ◽  
Pressure Overload ◽  
Elastic Stiffness ◽  
Fibrillar Collagen ◽  
Predominant Role ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Hypertrophied Myocardium ◽  
Protease Treatment

To determine whether and to what extent one component of the extracellular matrix, fibrillar collagen, contributes causally to abnormalities in viscoelasticity, collagen was acutely degraded by activation of endogenous matrix metalloproteinases (MMPs) with the serine protease plasmin. Papillary muscles were isolated from normal cats and cats with right ventricular pressure overload hypertrophy (POH) induced by pulmonary artery banding. Plasmin treatment caused MMP activation, collagen degradation, decreased the elastic stiffness constant, and decreased the viscosity constant in both normal and POH muscles. Thus, whereas many mechanisms may contribute to the abnormalities in myocardial viscoelasticity in the POH myocardium, changes in fibrillar collagen appear to play a predominant role.

scholarly journals Piperazine based Zirconium Oxy-Chloride (PzZrOCl) single crystal: A Third Order Nonlinear Optical material for Opto-electronic Device Applications

2021 ◽  
Author(s):  
Mullai R U ◽  
Sreenadha Rao Kanuru ◽  
R. Arul Jothi ◽  
E. Vinoth ◽  
S. Gopinath ◽  
...  
Keyword(s):  
Single Crystals ◽  
Electronic Device ◽  
Green Emission ◽  
Elastic Stiffness ◽  
Visible Range ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Device Applications ◽  
Evaporation Technique ◽  
Laser Induced Damage

Abstract Single crystals of Piperazine Zirconium Oxy-Chloride (PzZrOCl) are grown successfully by slow evaporation technique for Opto-electronic device applications. Suitability of the material is estimated and reported as follows. Crystal habits, purity, crystallite size, microstructure and bulk crystals structures are essential parameters for device compatibility hence they were examined with basic characterization techniques and studied to estimate their effects on optoelectronic properties. The outcomes from structural aspects are reasonably good. The functional groups of a molecule, their bond vibration frequencies and mode of alignments have been examined by Fourier Transform Infrared spectroscopy (FT-IR). The transmittance (98%) in the entire visible range with lowest cut-off wavelength (215 nm) and green emission (545 nm) is another evidence of suitability. The thermal and mechanical strength via hardness, Mayer index, yield strength and elastic stiffness constant is evaluated; it is thermally stable up to 162°C, mechanically strong and belongs to soft category. Laser induced damage is estimated by using Nd:YAG laser of wavelength 1064 nm and the observed values is three times higher than KDP, 1.2 times higher than LAPP. The optical nonlinear nature and its efficiency are examined by using Z-scan technique. The analysis discussed in detailed and the results strongly recommends PzZrOCl single crystals are suitable for optical and electronic device applications.

Synthesis, growth mechanism and physical properties of vapour-deposited GaTe platelets

2014 ◽  
Vol 47 (6) ◽  
pp. 1841-1848 ◽  
Author(s):  
A. G. Kunjomana ◽  
M. Teena ◽  
K. A. Chandrasekharan
Keyword(s):  
Physical Properties ◽  
Growth Mechanism ◽  
Energy Gap ◽  
Radiation Detector ◽  
Elastic Stiffness ◽  
Scanning Electron Micrographs ◽  
Conductivity Type ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Gallium Telluride

The physical vapour deposition (PVD) method has been employed to yield gallium telluride (GaTe) platelets. The morphology and growth mechanism of these platelets were investigated with the aid of scanning electron micrographs. The stoichiometry and homogeneity of the grown samples were confirmed by chemical analysis. The X-ray diffraction (XRD) technique has been used to explore the structure and phase of the compound. On the basis of the Archimedes principle, the density of crystals was estimated to be 5.442 kg mm−3. The resistivity and conductivity type were determined by the van der Pauw method. UV–vis–NIR studies revealed a direct transition with an energy gap of 1.69 eV. Mechanical properties such as microhardness, toughness, Young's modulus and elastic stiffness constant of GaTe crystals in response to the stress field due to an external load were studied to realize their suitability for radiation detector applications. The present observations provide an insight into the physical properties of the vapour-grown GaTe platelets, which are found to be superior over their melt counterparts.

Quantification of Diastolic Viscoelastic Properties of Isolated Cardiac Muscle Cells

2001 ◽  
Author(s):  
Catalin F. Baicu ◽  
Michael R. Zile
Keyword(s):  
Cardiac Muscle ◽  
Viscoelastic Properties ◽  
Three Dimensional ◽  
Pressure Overload ◽  
Muscle Cells ◽  
Elastic Stiffness ◽  
Experimental Conditions ◽  
Cardiac Muscle Cells ◽  
Diastolic Properties

Abstract Pathological processes which cause diastolic congestive heart failure (CHF), such as pressure overload hypertrophy (POH), produce abnormalities in the material properties of cardiac muscle cells (cardiomyocytes) and may selectively alter its elastic stiffness, viscosity, or both. Previous methods used to characterize these cardiomyocyte viscoelastic properties were constrained by specific biological and engineering limitations, which prevented testing in conditions that mimic normal physiology. The current study proposes an uniaxial variable-rate stretching method, in which isolated cardiomyocytes embedded in a three-dimensional gel matrix were subjected to stretch. Physiological Ca++ (2.5 mM) and rapid stretch rates up to 100 μm/sec provided experimental conditions parallel to in vivo physiology. The proposed method identified and individually quantified both cellular stiffness and viscosity, and showed that POH increased both elastic and viscous cardiomyocyte diastolic properties.

Ideal Cleavage Fracture of Transition-Metal Silicides: A Comparison Analysis

1998 ◽  
Vol 552 ◽  
Author(s):  
M. H. Yoo ◽  
K. Yoshimi
Keyword(s):  
Transition Metal ◽  
Interplanar Spacing ◽  
Elastic Stiffness ◽  
Comparison Analysis ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Metal Silicides ◽  
Cleavage Energy ◽  
Simple Empirical Model ◽  
The Ideal

ABSTRACTA simple empirical model for the ideal cleavage energy, resulting from a rigid-body separation, is proposed in terms of four variables, viz., the elastic stiffness constant, the interplanar spacing, and two adjustable length parameters. The ratio of these parameters is assessed based on the available results of ab-initio slab-supercell calculations. Ideal cleavage energies and stress intensity factors of transition-metal silicides are estimated, and the available fracture toughness data are discussed.

The Effect of Secondary Piezoelectric Effect on the Measuring Precision of Quartz Dynamometers

2005 ◽  
Vol 291-292 ◽  
pp. 519-524
Author(s):  
L.P. Shi ◽  
Bao Yuan Sun ◽  
Min Qian
Keyword(s):  
Direct Effect ◽  
Piezoelectric Effect ◽  
Elastic Stiffness ◽  
Elastic Compliance ◽  
Milling Force ◽  
Piezoelectric Quartz ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Theory And Experiment ◽  
Quartz Sensor

People apply quartz dynamometers to measure of milling force extensively. It is mainly made from piezoelectric quartz sensor. In this paper, the theory of the secondary piezoelectric effect is deduced by four kinds of piezoelectric equations. With the measuring the quartz stack secondary piezoelectric effect is verified. By theory and experiment we can show that the secondary piezoelectric effect makes elastic compliance constant of piezoelectric quartz smaller and do elastic stiffness constant of piezoelectric quartz bigger. Obviously, the secondary piezoelectric effect will have direct effect on the measuring precision of quartz dynamometers. So the investigations of secondary piezoelectric effect contribute to improving measuring precision of piezoelectric dynamometers.

scholarly journals Investigation on growth, optical and thermal properties of stilbazolium derivative crystal: 4-N,N-dimethylamino-4′-N′-methylstilbazolium 2,4-dimethylbenzenesulfonate

2016 ◽  
Vol 34 (4) ◽  
pp. 811-818 ◽  
Author(s):  
I. Md. Zahid ◽  
S. Kalaiyarasi ◽  
M. Krishna Kumar ◽  
T. Ganesh ◽  
V. Jaisankar ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Elastic Stiffness ◽  
Spectral Studies ◽  
Ionic Exchange ◽  
Growth Technique ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Transmission Region ◽  
Ft Ir ◽  
Raman Spectral

AbstractMetathesis ionic exchange reaction process was used to synthesize a novel nonlinear optical material: 4-N,N-dimethylamino-4′- N′-methylstilbazolium 2,4-dimethylbenzenesulfonate (DSDMS). The growth of DSDMS single crystals was carried out by adopting the solution growth technique. The crystal perfection and lattice parameters were elucidated from single XRD and powder XRD, respectively and its morphology was interpreted by WinXMorph program. FT-IR and Raman spectral analyses confirmed the existence of functional groups and their corresponding vibrational modes. UV-Vis spectral studies revealed the optical transmission region. Mechanical stability of the crystal was determined from Vickers microhardness number Hv, Meyer’s index n and elastic stiffness constant C11. Dielectric and thermal behavior of the grown crystal were elucidated by using impedance analyser and thermogravimetric analysis.

Constitutive properties of hypertrophied myocardium: cellular contribution to changes in myocardial stiffness

2002 ◽  
Vol 282 (6) ◽  
pp. H2173-H2182 ◽  
Author(s):  
Todd S. Harris ◽  
Catalin F. Baicu ◽  
Chester H. Conrad ◽  
Masaaki Koide ◽  
J. Michael Buckley ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Material Properties ◽  
Pressure Overload ◽  
Elastic Stiffness ◽  
Viscous Damping ◽  
Myocardial Stiffness ◽  
Hypertrophied Myocardium ◽  
Resultant Effect ◽  
Constitutive Properties

Recent studies have suggested that pressure overload hypertrophy (POH) alters the viscoelastic properties of individual cardiocytes when studied in isolation. However, whether these changes in cardiocyte properties contribute causally to changes in the material properties of the cardiac muscle as a whole is unknown. Accordingly, a selective, isolated, acute change in cardiocyte constitutive properties was imposed in an in vitro system capable of measuring the resultant effect on the material properties of the composite cardiac muscle. POH caused an increase in both myocardial elastic stiffness, from 20.5 ± 1.3 to 28.4 ± 1.8, and viscous damping, from 15.2 ± 1.1 to 19.8 ± 1.5 s (normal vs. POH, P < 0.05), respectively. Recent studies have shown that cardiocyte constitutive properties could be acutely altered by depolymerizing the microtubules with colchicine. Colchicine caused a significant decrease in the viscous damping in POH muscles (19.8 ± 1.5 s at baseline vs. 14.7 ± 1.3 s after colchicine, P < 0.05). Therefore, myocardial material properties can be altered by selectively changing the constitutive properties of one element within this muscle tissue, the cardiocyte. Changes in the constitutive properties of the cardiocytes themselves contribute to the abnormalities in myocardial stiffness and viscosity that develop during POH.

An analysis of the ferroelastic transition in Pb(Zr0.53Ti0.47)O3:Gd through the elastic stiffness constant

2021 ◽  
pp. 1-9
Author(s):  
Y. de Armas Figueroa ◽  
J. Portelles ◽  
Rene López-Noda ◽  
J. Fuentes ◽  
H´Linh Hmŏk ◽  
...  
Keyword(s):  
Elastic Stiffness ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant

Mechanical Studies of Nonlinear Optical γ-Glycine Single Crystal Grown in the Presence of Lithium Nitrate

2012 ◽  
Vol 584 ◽  
pp. 145-149
Author(s):  
M. Vijayalakshmi ◽  
C. Yogambal ◽  
D. Rajan Babu ◽  
R. Ezhil Vizhi
Keyword(s):  
Single Crystal ◽  
Visible Region ◽  
Hardness Test ◽  
Elastic Stiffness ◽  
Lithium Nitrate ◽  
X Ray Diffraction ◽  
Elastic Stiffness Constant ◽  
Stiffness Constant ◽  
Crystalline Nature ◽  
Uv Visible

Single Crystal of γ-glycine lithium nitrate with non-linear optical material have been grown by slow evaporation method at room temperature. Structural and Crystalline nature of the grown γ-glycine lithium nitrate crystal was confirmed by powder X-ray diffraction technique. UV-Visible transmittance study was performed to analyze optical transparency of γ-glycine crystal and found that the crystal was transparent in the entire visible region. The mechanical properties of the grown crystal was subjected to Vickers hardness test and the Brittleness index (Bi), Fracture toughness (Kc), Elastic stiffness constant (C11) were estimated.

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