Role of t-tubule remodeling on mechanisms of abnormal calcium release during heart failure development in canine ventricle

2021 ◽  
Vol 320 (4) ◽  
pp. H1658-H1669
Author(s):  
Sean Yamakawa ◽  
Daniel Wu ◽  
Mona Dasgupta ◽  
Havisha Pedamallu ◽  
Binita Gupta ◽  
...  
Keyword(s):  
Heart Failure ◽  
Linear Relationship ◽  
Dimensional Analysis ◽  
Calcium Release ◽  
Three Dimensional ◽  
Threshold Value ◽  
Critical Component ◽  
Chemically Induced

Three-dimensional analysis of t-tubule density showed t-tubule disruption throughout the whole myocyte in failing dog ventricle. A double-linear relationship between Ca2+ release and t-tubule density displays a steeper slope at t-tubule densities below a threshold value (∼1.5%) above which there is little effect on Ca2+ release (T-tubule reserve). T-tubule loss increases incidence of triggered Ca2+ waves. Chemically induced t-tubule disruption suggests that t-tubule loss alone is a critical component of abnormal Ca2+ cycling in heart failure.

The Parametric Analysis of the Threshold Value Judging Mechanism in MEMS Safety and Arming Device

2015 ◽  
Vol 645-646 ◽  
pp. 968-971
Author(s):  
Fu Fu Wang ◽  
Wen Zhong Lou ◽  
Fang Yi Liu ◽  
Da Kui Wang ◽  
Ming Rong Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Threshold Value ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Long Distance ◽  
And Control ◽  
The Mathematical Model ◽  
The Finite Element Model

In this paper, a mechanical MEMS S&A device has been proposed. The size of the device is 10mm×13mm×0.5mm. The role of the threshold value judging mechanism is to determine the environment suffered by centrifugal force and control the sub-centrifugal slider not movement under the threshold, so as to effectively guarantee the time of long-distance arming. Through establishing the three-dimensional model of threshold value judging mechanism, establishing the force and the parameters of locking-releasing mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory and establishing the finite element model by using ANSYS/LS-DYNA, appropriate threshold value judging mechanism is designed to meet two items, one item is the deformation of threshold value rod is not enough to release sub-centrifugal slider when the speed is less than 60000r/min; the other item is deformation of threshold value rod can release sub-centrifugal slider when the speed is more than 60000r/min.

scholarly journals The effects of suction on the nonlinear stability of the three-dimensional boundary layer above a rotating disc

1992 ◽  
Vol 436 (1897) ◽  
pp. 405-415 ◽  
Keyword(s):  
Linear Problem ◽  
Three Dimensional ◽  
Threshold Value ◽  
Neutral Stability ◽  
Lower Branch ◽  
Rotating Disc ◽  
Weakly Nonlinear ◽  
Nonlinear Properties ◽  
Dimensional Boundary

There exist two types of stationary instability of the flow over a rotating disc corresponding to the upper-branch, inviscid mode and the lower-branch mode, which has a triple deck structure, of the neutral stability curve. A theoretical investigation of the linear problem and an account of the weakly nonlinear properties of the lower branch-modes have been undertaken by P. Hall and S. MacKerrell respectively. Motivated by recent reports of experimental sightings of the lower-branch mode and an examination of the role of suction on the linear stability properties of the flow here we investigate the effects of suction on the nonlinear disturbance described by S. MacKerrell. The additional analysis required to incorporate suction is relatively straightforward and enables us to derive an amplitude equation which describes the evolution of the mode. For each value of the suction a threshold value of the disturbance amplitude is obtained; modes of size greater than this threshold grow without limit as they develop away from the point of neutral stability.

In situ investigation of the primary recrystallization of alpha titanium in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 634-635
Author(s):  
S. Naka ◽  
R. Penelle ◽  
R. Valle
Keyword(s):  
Dimensional Analysis ◽  
Texture Evolution ◽  
Cold Work ◽  
Three Dimensional ◽  
Primary Recrystallization ◽  
Thin Foils ◽  
In Situ Investigation ◽  
Grain Growth Model ◽  
Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

Protective role of peroxiredoxin-4 in heart failure

2020 ◽  
Vol 134 (1) ◽  
pp. 71-72
Author(s):  
Naseer Ahmed ◽  
Masooma Naseem ◽  
Javeria Farooq
Keyword(s):  
Heart Failure ◽  
Cardiac Fibroblasts ◽  
Protective Role ◽  
Oxidative Stress Markers ◽  
Stress Markers ◽  
Total Antioxidant ◽  
Galectin 3 ◽  
Consequent Increase ◽  
And Oxidative Stress

Abstract Recently, we have read with great interest the article published by Ibarrola et al. (Clin. Sci. (Lond.) (2018) 132, 1471–1485), which used proteomics and immunodetection methods to show that Galectin-3 (Gal-3) down-regulated the antioxidant peroxiredoxin-4 (Prx-4) in cardiac fibroblasts. Authors concluded that ‘antioxidant activity of Prx-4 had been identified as a protein down-regulated by Gal-3. Moreover, Gal-3 induced a decrease in total antioxidant capacity which resulted in a consequent increase in peroxide levels and oxidative stress markers in cardiac fibroblasts.’ We would like to point out some results stated in the article that need further investigation and more detailed discussion to clarify certain factors involved in the protective role of Prx-4 in heart failure.

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