Non-steady-state photoelectromotive-force generation in an interferometer with optoelectronic feedback

2008 ◽  
Vol 77 (3) ◽  
Author(s):  
Mikhail Bryushinin ◽  
Igor Sokolov
Keyword(s):  
Steady State ◽  
Force Generation ◽  
Photoelectromotive Force

Steady-state dependence of stress on cross-bridge phosphorylation in the swine carotid media

1992 ◽  
Vol 262 (6) ◽  
pp. C1388-C1391 ◽  
Author(s):  
P. Di Blasi ◽  
D. Van Riper ◽  
R. Kaiser ◽  
C. M. Rembold ◽  
R. A. Murphy
Keyword(s):  
Steady State ◽  
State Dependence ◽  
Force Generation ◽  
Cross Sectional ◽  
Active Stress ◽  
Cross Bridge ◽  
Bridge Model ◽  
Steady State Levels ◽  
Force Maintenance ◽  
Cross Bridges

Tonic contractions of the swine carotid media are typically characterized by initial transients in myoplasmic [Ca2+] and cross-bridge phosphorylation followed by force maintenance with reduced intracellular [Ca2+] and cross-bridge phosphorylation (“latch”). The presence of effective mechanisms in the carotid media to limit steady-state myoplasmic [Ca2+] and cross-bridge phosphorylation to modest increases over resting values has limited experimental attempts to determine the dependence of active stress (force/tissue cross-sectional area) on cross-bridge phosphorylation. In this study, we employed stimulation protocols that combined effective contractile agonists with inhibitors of Ca2+ extrusion or sequestration to achieve high steady-state levels of cross-bridge phosphorylation (up to 60%). Increases in cross-bridge phosphorylation from 30 to 60% were not associated with significant increases in stress in agreement with the predictions of Hai and Murphy [Am. J. Physiol. 254 (Cell Physiol. 23): C99-C106, 1988] four-state cross-bridge model for the carotid media. Thus cross-bridge phosphorylation may suffice to determine force generation in vascular smooth muscle if both phosphorylated and dephosphorylated attached cross bridges (or latch bridges) contribute to active stress.

Active particles under confinement and effective force generation among surfaces

Soft Matter ◽  
2018 ◽  
Vol 14 (44) ◽  
pp. 9044-9054 ◽  
Author(s):  
Lorenzo Caprini ◽  
Umberto Marini Bettolo Marconi
Keyword(s):  
Steady State ◽  
Thermal Noise ◽  
Active Suspension ◽  
Force Generation ◽  
One Dimensional ◽  
Effective Force ◽  
Active Particles ◽  
Geometric Confinement

We consider the effect of geometric confinement on the steady-state properties of a one-dimensional active suspension subject to thermal noise.

Non-steady-state photoelectromotive force in reduced lithium niobate crystals

1999 ◽  
Vol 86 (5) ◽  
pp. 2389-2392 ◽  
Author(s):  
H. Veenhuis ◽  
K. Buse ◽  
E. Krätzig ◽  
N. Korneev ◽  
D. Mayorga
Keyword(s):  
Steady State ◽  
Lithium Niobate ◽  
Photoelectromotive Force ◽  
Lithium Niobate Crystals

Abstract 345: R403Q Mutation Increases the Rate of Force Redevelopment in 2 Month Mice

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Camille Birch ◽  
John P Konhilas
Keyword(s):  
Steady State ◽  
Hypertrophic Cardiomyopathy ◽  
Cardiac Tissue ◽  
Muscle Length ◽  
Familial Hypertrophic Cardiomyopathy ◽  
Force Generation ◽  
Energetic Cost ◽  
Cardiac Pathology ◽  
Myofilament Function ◽  
Isotonic Shortening

Familial hypertrophic cardiomyopathy is a primary disease of the sarcomere. The R403Q mutation resides at the actin-interaction site on myosin and leads to progressive hypertrophic cardiomyopathy which progresses towards heart failure. Along with deteriorating cardiac function, these hearts experience an overall change in metabolic landscape, suggesting altered energetic function in hearts that express the R403Q mutation. We tested the hypothesis that the R403Q mutation intrinsically increases the energetic cost of contraction. To do this, we determined myofilament function in demembranated cardiac trabeculae from male wild-type (WT) and R403Q mice at 2 months of age, prior to overt signs of cardiac pathology. Firstly, steady-state Ca2+ sensitivity of force generation was not significantly different between male R403Q (n=4) and WT counterparts (n=2) consistent with previous findings. Secondly, the rate of force redevelopment (ktr) in skinned cardiac tissue was measured following unloaded isotonic shortening and a rapid re-stretch to 15% of the original muscle length at a sarcomere length of 2.0μm. R403Q mice display an increased rate of force redevelopment (49.89 s-1 ± 8.13, n = 4) compared to WT counterparts (24.52 ± 4.29, n = 6) at maximal activation indicating an increase in the apparent rates of crossbridges entering and leaving force-generating states (p < 0.05). In conclusion, the R403Q mutation does not impact steady-state Ca2+ sensitivity of force but increases total crossbridge cycling rate suggesting a higher energy cost of force generation. Future studies are aimed at determining the energetic cost of contraction in R403Q hearts and how this increased energetic cost leads to hypertrophic cardiomyopathy.

1,25(OH)2D3 modulates intracellular Ca2+ and force generation in resistance arteries

1996 ◽  
Vol 270 (1) ◽  
pp. H230-H237 ◽  
Author(s):  
K. Bian ◽  
K. Ishibashi ◽  
R. D. Bukoski
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Force ◽  
Force Generation ◽  
Myosin Light Chain Phosphorylation ◽  
Resistance Artery ◽  
Resistance Arteries ◽  
Active Stress

The mechanism by which 1 alpha,25-dihydroxycholecalciferol [1,25(OH)2D3] enhances smooth muscle force generation was examined. Rats were injected on three mornings with 1,25(OH)2D3 (35 ng/100 g) or vehicle, and on the fourth morning mesenteric resistance arteries were isolated and used for simultaneous measurement of intracellular Ca2+ and force or myosin light chain phosphorylation. 1,25(OH)2D3 did not affect media thickness or wall-to-lumen ratio, but it increased basal intracellular Ca2+ (vehicle = 49.2 +/- 2.2 nM vs. 1,25(OH)2D3 = 65.9 +/- 4.0 nM, P < 0.05, n = 24-26 rats). 1,25(OH)2D3 enhanced the active stress and intracellular Ca2+ responses to increasing doses of norepinephrine, and the increases were normalized by verapamil (10 microM). In a second group of animals, 1,25(OH)2D3 significantly increased both basal intracellular Ca2+ and light chain phosphorylation and the active stress and Ca2+ mobilization responses to norepinephrine (10 microM). The hormone did not affect peak or steady-state light chain phosphorylation. Myofilament Ca2+ sensitivity, determined during stimulation with 2 microM norepinephrine, was depressed in vessels isolated from rats treated with 1,25(OH)2D3 [vehicle Ca2+ 50% effective dose (ED50) = 82.7 +/- 3.8 nM vs. 1,25(OH)2D3 = 104.8 +/- 4.9 nM, P = 0.002]. We conclude that 1,25(OH)2D3 enhances resistance artery force generation by altering smooth muscle Ca2+ homeostasis, with effects on basal and verapamil-sensitive, agonist-induced Ca2+ mobilization.

scholarly journals Non-steady-state photoelectromotive force in an AlN crystal

2012 ◽  
Vol 86 (8) ◽  
Author(s):  
M. Bryushinin ◽  
V. Kulikov ◽  
E. Mokhov ◽  
S. Nagalyuk ◽  
I. Sokolov
Keyword(s):  
Steady State ◽  
Photoelectromotive Force
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