A novel approach for the estimation of the efficiency of steady-state fiber bed coalescence

2013 ◽  
Vol 104 ◽  
pp. 268-275 ◽  
Author(s):  
Dragan D. Govedarica ◽  
Radmila M. Šećerov Sokolović ◽  
Dunja S. Sokolović ◽  
Slobodan M. Sokolović
Keyword(s):  
Steady State ◽  
Novel Approach

Abstract 89: The Ventriculo-Ventricular Coupling Index: A Novel Approach to Assessing Biventricular Function

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Navin K Kapur ◽  
Mark J Aronovitz ◽  
Robert Blanton ◽  
Emily Mackey ◽  
Vikram Paruchuri ◽  
...  
Keyword(s):  
Heart Failure ◽  
Steady State ◽  
Left Ventricular ◽  
External Jugular Vein ◽  
Arterial Elastance ◽  
Left Heart Failure ◽  
Novel Approach ◽  
Coupling Index ◽  
Ventricular Efficiency ◽  
The Right

Bi-ventricular (Bi-V) function in primary pulmonary hypertension (PPH) or PH secondary to left heart failure (SPH) remains difficult to characterize. As a measure of ventricular efficiency, ventriculo-arterial coupling (VAC) is calculated as the ratio of effective arterial elastance (Ea) to end-systolic elastance (Ees). No measure currently assesses ventriculo-ventricular coupling (VVC). Therefore, we developed a novel catheter-based approach to quantify Bi-V function using pressure-volume loop (PVL) analysis and hypothesized that Bi-V VAC ratios, defined as the VVC index (VVCI), may discriminate PPH and SPH. Methods: Adult male mice (n=6/group) underwent constriction of the pulmonary artery (PAC) or thoracic aorta (TAC) to model PPH and SPH respectively. Sham-operated animals underwent a left thoracotomy. Closed chest simultaneous Bi-V catheterization was performed after 7 days in PPH and 10 weeks in SPH. Conductance catheters were used for right and left ventricular PVL analysis via the right external jugular vein and right common carotid artery under steady-state conditions and with variable preload. Results: Steady-state Bi-V PVL and changes in VAC ratios and the VVCI are shown below. In sham mice VAC ratios and the VVCI reflect optimal ventricular efficiency. In PPH, the VVCI is significantly increased, while in SPH, the VVCI is significantly decreased compared to controls. Conclusion: These results identify a novel method to quantify Bi-V function in mice and further show that the VVCI can distinguish PPH and SPH. These findings have important implications for examining cardiac function in preclinical and clinical studies of left- and right-sided heart failure.

scholarly journals A novel approach to distinguish between enzyme mechanisms: quasi-steady-state kinetic analysis of the prostaglandin H synthase peroxidase reaction

2003 ◽  
Vol 372 (3) ◽  
pp. 713-724 ◽  
Author(s):  
Peter V. VRZHESHCH ◽  
Elena A. BATANOVA ◽  
Alevtina T. MEVKH ◽  
Sergei D. VARFOLOMEEV ◽  
Irina G. GAZARYAN ◽  
...  
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Catalytic Cycle ◽  
Prostaglandin H Synthase ◽  
Compound I ◽  
Novel Approach ◽  
Steady State Kinetic ◽  
Enzyme Intermediates ◽  
Prostaglandin H ◽  
State Kinetic

A method of analysis for steady-state kinetic data has been developed that allows relationships between key partial reactions in the catalytic cycle of a functioning enzyme to be determined. The novel approach is based on a concept of scalar and vector ‘kinetic connectivities’ between enzyme intermediates in an arbitrary enzyme mechanism. The criterion for the agreement between experimental data and a proposed kinetic model is formulated as the kinetic connectivity of intermediate forms of the enzyme. This concept has advantages over conventional approaches and is better able to describe the complex kinetic behaviour of prostaglandin H synthase (PGHS) when catalysing the oxidation of adrenaline by H2O2. To interpret the experimental data for PGHS, a generalized model for multi-substrate enzyme reactions was developed with provision for irreversible enzyme inactivation. This model showed that two enzyme intermediates must undergo inactivation during the catalytic cycle. These forms are proposed to be PGHS compound I and a compound I–adrenaline complex.

A Hydraulic Rotary Switched-Inertance Servo-Transformer

1988 ◽  
Vol 110 (2) ◽  
pp. 144-150 ◽  
Author(s):  
F. T. Brown ◽  
S. C. Tentarelli ◽  
S. Ramachandran
Keyword(s):  
Steady State ◽  
High Frequency ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Complete Solution ◽  
Partial Solution ◽  
State Theory ◽  
Novel Approach ◽  
Flow Through ◽  
Theory And Experiments

Switched-reactance hydraulics represents a radically novel approach to the control of fluid power, since the proportional metering of flow through adjustable orifices is eliminated, and the inertive properties of the fluid substituted. Potential advantages in bandwidth, linearity, and efficiency have been indicated. This paper presents the first steady-state theory and experiments with a rotary fluid switch, which accomplishes the needed pulse-width modulation at a desirably high frequency. Cavitation problems are observed, means of their partial solution are implemented, and means of a more complete solution are indicated.

Steady-State Wave Propagation in Multilayered Viscoelastic Media Excited by a Moving Dynamic Distributed Load

2009 ◽  
Vol 76 (4) ◽  
Author(s):  
Lu Sun ◽  
Wenjun Gu ◽  
Feiquan Luo
Keyword(s):  
Steady State ◽  
Moving Load ◽  
Impulse Response Function ◽  
Constitutive Models ◽  
Numerical Algorithms ◽  
Point Load ◽  
Fast Evaluation ◽  
Viscoelastic Media ◽  
Distributed Load ◽  
Novel Approach

An analytical solution of steady-state dynamic response of a multilayered viscoelastic medium to a moving distributed load is obtained using a novel approach that combines transfer matrix method with Sun’s convolution representation integrated over impulse response function of the layered medium. The layered media under consideration include elastic and viscoelastic media with four different viscoelastic constitutive models, while the moving load is allowed to have a circular spatial distribution, which is more realistic for mimicking tire footprint than a commonly used point load. Efficient numerical algorithms based on fast evaluation of various integral transformations and their inversions are developed and validated through numerical example.

scholarly journals Adapting Footfall Rhythmicity to Auditory Perturbations Affects Resilience of Locomotor Behavior: A Proof-of-Concept Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Deepak K. Ravi ◽  
Caroline C. Heimhofer ◽  
William R. Taylor ◽  
Navrag B. Singh
Keyword(s):  
Steady State ◽  
Fall Risk ◽  
Recovery Time ◽  
Center Of Mass ◽  
Locomotor Behavior ◽  
Proof Of Concept ◽  
Limited Information ◽  
Novel Approach ◽  
Temporal Adaptation ◽  
The Mean

For humans, the ability to effectively adapt footfall rhythm to perturbations is critical for stable locomotion. However, only limited information exists regarding how dynamic stability changes when individuals modify their footfall rhythm. In this study, we recorded 3D kinematic activity from 20 participants (13 males, 18–30 years old) during walking on a treadmill while synchronizing with an auditory metronome sequence individualized to their baseline walking characteristics. The sequence then included unexpected temporal perturbations in the beat intervals with the subjects required to adapt their footfall rhythm accordingly. Building on a novel approach to quantify resilience of locomotor behavior, this study found that, in response to auditory perturbation, the mean center of mass (COM) recovery time across all participants who showed deviation from steady state (N = 15) was 7.4 (8.9) s. Importantly, recovery of footfall synchronization with the metronome beats after perturbation was achieved prior (+3.4 [95.0% CI +0.1, +9.5] s) to the recovery of COM kinematics. These results highlight the scale of temporal adaptation to perturbations and provide implications for understanding regulation of rhythm and balance. Thus, our study extends the sensorimotor synchronization paradigm to include analysis of COM recovery time toward improving our understanding of an individual’s resilience to perturbations and potentially also their fall risk.

Novel Approach to the Analysis of Fluctuations in Steady-State Nucleate Boiling

1994 ◽  
pp. 1741-1748 ◽  
Author(s):  
Eric W. Roth ◽  
J. S. Semura ◽  
L. C. Brodie ◽  
Erik Bodegom
Keyword(s):  
Steady State ◽  
Nucleate Boiling ◽  
Novel Approach

An Attentional Model for the Conceptual Construction of Units and Number

1981 ◽  
Vol 12 (2) ◽  
pp. 83-94
Author(s):  
Ernst Von Glasersfeld
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Steady State ◽  
Theoretical Model ◽  
Attentional Model ◽  
Reflective Abstraction ◽  
Conceptual Structures ◽  
Novel Approach ◽  
Conceptual Construction ◽  
The Central Nervous System

A theoretical model is proposed that explicates the generation of conceptual structures from unitary sensory objects to abstract constructs that satisfy the criteria generally stipulated for concepts of “number”: independence from sensory properties, unity of composites consisting of units, and potential numerosity. The model is based on the assumption that attention operates not as a steady state but as a pulselike phenomenon that can, but need not, be focused on sensory signals in the central nervous system. Such a view of attention is compatible with recent findings in the neurophysiology of perception and provides, in conjunction with Piaget's postulate of empirical and reflective abstraction, a novel approach to the analysis of concepts that seem indispensable for the development of numerical operations.

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