Non-monotonic Effects of Intrinsic Stiffness and Concentration of Polyelectrolytes on the Electro-Sorption

2021 ◽  
Vol 54 (4) ◽  
pp. 1801-1810
Author(s):  
Jian Jiang
Keyword(s):  
Intrinsic Stiffness

scholarly journals Determination of the region of the limiting states occurrence in RVS-20000 with the subsidence of the external bottom contour

2018 ◽  
Vol 239 ◽  
pp. 06002
Author(s):  
P.V. Chepur ◽  
A.A. Tarasenko ◽  
A.A. Gruchenkova
Keyword(s):  
Technical Condition ◽  
Element Analysis ◽  
Metal Structures ◽  
Software Complex ◽  
Managerial Decisions ◽  
The Finite Element Analysis ◽  
Steel Tank ◽  
Intrinsic Stiffness ◽  
Bottom Contour

The problem of the limiting states occurrence in the structures of a vertical steel tank is investigated in this work. To study the SSS of the metal structures of the object, the authors created a numerical model of the RVS-20000 tank in the ANSYS software complex. The model considers the maximum number of elements with their geometry and connections affecting the tank SSS under non-axisymmetric loading, including beyond the elasticity of steel. Dependences between the parameters of intrinsic stiffness of the VST are obtained. The results of the finite element analysis made it possible to develop a technique for assessing the technical condition of the structure with the development of irregular subsidence of the external bottom contour. The proposed technique can be used by both operating and design organizations in making managerial decisions regarding the repair of RVS-20000 subjected to the base subsidence.

scholarly journals Entropy driven chain effects on ligation chemistry

2015 ◽  
Vol 6 (2) ◽  
pp. 1061-1074 ◽  
Author(s):  
Kai Pahnke ◽  
Josef Brandt ◽  
Ganna Gryn'ova ◽  
Peter Lindner ◽  
Ralf Schweins ◽  
...  
Keyword(s):  
Building Block ◽  
Chain Structure ◽  
Step Change ◽  
Side Chain ◽  
On Demand ◽  
Bonding Systems ◽  
Intrinsic Stiffness

Entropic chain effects on dynamic bonding reactions are shown to enable the tuning of reaction equilibria not only by changing the mass of the reactants, but also by merely altering the building block side chain structure and thus the intrinsic stiffness. The findings enable a step change for the design of on-demand bonding systems and reversible ligation chemistry in general.

scholarly journals C-terminal tail polyglycylation and polyglutamylation alter microtubule mechanical properties

2019 ◽  
Author(s):  
Kathryn P. Wall ◽  
Harold Hart ◽  
Thomas Lee ◽  
Cynthia Page ◽  
Taviare L. Hawkins ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Mechanisms ◽  
High Stress ◽  
Resonance Spectroscopy ◽  
Post Translational Modification ◽  
Cellular Functions ◽  
Peptide Backbone ◽  
Post Translational Modifications ◽  
Intrinsic Stiffness ◽  
Insight Into

ABSTRACTMicrotubules are biopolymers that perform diverse cellular functions. The regulation of microtubule behavior occurs in part through post-translational modification of both the α- and β- subunits of tubulin. One class of modifications is the heterogeneous addition of glycine and glutamate residues to the disordered C-terminal tails of tubulin. Due to their prevalence in stable, high stress cellular structures such as cilia, we sought to determine if these modifications alter the intrinsic stiffness of microtubules. Here we describe the purification and characterization of differentially-modified pools of tubulin from Tetrahymena thermophila. We found that glycylation on the α-C-terminal tail is a key determinant of microtubule stiffness, but does not affect the number of protofilaments incorporated into microtubules. We measured the dynamics of the tail peptide backbone using nuclear magnetic resonance spectroscopy. We found that the spin-spin relaxation rate (R2) showed a pronounced decreased as a function of distance from the tubulin surface for the α-tubulin tail, indicating that the α-tubulin tail interacts with the dimer surface. This suggests that the interactions of the α-C-terminal tail with the tubulin body contributes to the stiffness of the assembled microtubule, providing insight into the mechanism by which glycylation and glutamylation can alter microtubule mechanical properties.SIGNIFICANCEMicrotubules are regulated in part by post-translational modifications including the heterogeneous addition of glycine and glutamate residues to the C-terminal tails. By producing and characterizing differentially-modified tubulin, this work provides insight into the molecular mechanisms of how these modifications alter intrinsic microtubule properties such as flexibility. These results have broader implications for mechanisms of how ciliary structures are able to function under high stress.

scholarly journals IRSBot-2: A Novel Two-DOF Parallel Robot for High-Speed Operations

2011 ◽  
Author(s):  
Coralie Germain ◽  
Se´bastien Briot ◽  
Victor Glazunov ◽  
Ste´phane Caro ◽  
Philippe Wenger
Keyword(s):  
High Speed ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Kinematic Chains ◽  
Robot Architecture ◽  
Intrinsic Stiffness ◽  
Two Degree Of Freedom

This paper presents a novel two-degree-of-freedom (DOF) translational parallel robot for high-speed applications named the IRSBot-2 (acronym for IRCCyN Spatial Robot with 2 DOF). Unlike most two-DOF robots dedicated to planar translational motions, this robot has two spatial kinematic chains which confers a very good intrinsic stiffness. First, the robot architecture is described. Then, its actuation and constraint singularities are analyzed. Finally, the IRSBot-2 is compared to its two-DOF counterparts based on elastostatic performances.

scholarly journals Functionalization of Partially Bio-Based Poly(Ethylene Terephthalate) by Blending with Fully Bio-Based Poly(Amide) 10,10 and a Glycidyl Methacrylate-Based Compatibilizer

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1331 ◽  
Author(s):  
Maria Jorda ◽  
Sergi Montava-Jorda ◽  
Rafael Balart ◽  
Diego Lascano ◽  
Nestor Montanes ◽  
...  
Keyword(s):  
Glycidyl Methacrylate ◽  
Ethylene Terephthalate ◽  
Thermomechanical Properties ◽  
Interesting Aspect ◽  
Binary Blends ◽  
Poly Ethylene Terephthalate ◽  
Scanning Electron Microcopy ◽  
Poly Ethylene ◽  
Methacrylate Copolymer ◽  
Intrinsic Stiffness

This work shows the potential of binary blends composed of partially bio-based poly(ethyelene terephthalate) (bioPET) and fully bio-based poly(amide) 10,10 (bioPA1010). These blends are manufactured by extrusion and subsequent injection moulding and characterized in terms of mechanical, thermal and thermomechanical properties. To overcome or minimize the immiscibility, a glycidyl methacrylate copolymer, namely poly(styrene-ran-glycidyl methacrylate) (PS-GMA; Xibond™ 920) was used. The addition of 30 wt % bioPA provides increased renewable content up to 50 wt %, but the most interesting aspect is that bioPA contributes to improved toughness and other ductile properties such as elongation at yield. The morphology study revealed a typical immiscible droplet-like structure and the effectiveness of the PS-GMA copolymer was assessed by field emission scanning electron microcopy (FESEM) with a clear decrease in the droplet size due to compatibilization. It is possible to conclude that bioPA1010 can positively contribute to reduce the intrinsic stiffness of bioPET and, in addition, it increases the renewable content of the developed materials.

Muscle stiffness in human ankle dorsiflexors: intrinsic and reflex components

1988 ◽  
Vol 60 (3) ◽  
pp. 1110-1121 ◽  
Author(s):  
T. Sinkjaer ◽  
E. Toft ◽  
S. Andreassen ◽  
B. C. Hornemann
Keyword(s):  
Mechanical Response ◽  
Voluntary Contraction ◽  
Muscle Stiffness ◽  
Flexor Muscle ◽  
Muscle Properties ◽  
Decerebrate Cat ◽  
Human Ankle ◽  
Cross Bridges ◽  
Intrinsic Stiffness ◽  
Ankle Dorsiflexors

1. The purpose of this study was to evaluate the mechanical response to stretch in normal human ankle dorsiflexors at different levels of voluntary contraction. In an active muscle, the total mechanical response is the sum of the intrinsic response from the contractile apparatus, the response from passive tissues, and the reflex mediated response. Each of these components was investigated. 2. The total incremental stiffness was defined as the ratio between the torque increment and the amplitude of the stretch. In 14 subjects the total stiffness increased from approximately 0.6 N.m/deg to approximately 2.5 N.m/deg at 50% of MVC and remained constant (+/- 10%) from 30 to 80% of MVC. 3. The contribution to incremental stiffness from intrinsic muscle properties was measured during electrical stimulation of the deep peroneal nerve at 7-50 Hz. Intrinsic stiffness increased linearly with torque from approximately 0.5 N.m/deg to approximately 2.5 N.m/deg at 80% of MVC. 4. The reflex component (total minus intrinsic stiffness) had a maximum of 0.5-1.5 N.m/deg at 30-50% of MVC and was approximately zero at no and maximal contraction. For intermediate levels of contraction the reflex increased the stiffness with 40-100% of the intrinsic stiffness in this flexor muscle. 5. The reflex contribution to total stiffness began approximately 50 ms after onset of stretch and peaked 150-300 ms after onset of stretch. 6. Total, intrinsic, and reflex mediated stiffness were all nearly independent of the amplitude of stretch in the range from 2 to 7 degrees. The higher stiffness observed for 1 degree stretches could be due to "short range stiffness" of the cross bridges. 7. Stretching of a contracting muscle generates large force increments even for moderate amplitudes of stretch. Approximately half of this force increment is due to the stretch reflex, which makes the muscle stiffer than predicted from the intrinsic stiffness. These findings in human flexor muscles are surprisingly similar to previous findings in extensor muscles of the decerebrate cat.

Age-related differences in trunk intrinsic stiffness

2016 ◽  
Vol 49 (6) ◽  
pp. 926-932 ◽  
Author(s):  
Milad Vazirian ◽  
Iman Shojaei ◽  
Rebecca L. Tromp ◽  
Maury A. Nussbaum ◽  
Babak Bazrgari
Keyword(s):  
Age Related ◽  
Intrinsic Stiffness

scholarly journals The intrinsic stiffness of human trabecular meshwork cells increases with senescence

Oncotarget ◽  
2015 ◽  
Vol 6 (17) ◽  
pp. 15362-15374 ◽  
Author(s):  
Joshua T. Morgan ◽  
Vijay Krishna Raghunathan ◽  
Yow-Ren Chang ◽  
Christopher J. Murphy ◽  
Paul Russell
Keyword(s):  
Trabecular Meshwork ◽  
Trabecular Meshwork Cells ◽  
Intrinsic Stiffness

scholarly journals Molecular Mechanisms of Muscle Tone Impairment under Conditions of Real and Simulated Space Flight

Acta Naturae ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 85-97
Author(s):  
Boris S. Shenkman ◽  
Andrey K. Tsaturyan ◽  
Ivan M. Vihlyantsev ◽  
Inessa B. Kozlovskaya ◽  
Anatoliy I. Grigoriev
Keyword(s):  
Space Flight ◽  
Molecular Mechanisms ◽  
Simulated Microgravity ◽  
Muscle Tone ◽  
Muscle Stiffness ◽  
Hindlimb Suspension ◽  
Gravitational Unloading ◽  
Muscle Stretch ◽  
Intrinsic Muscle ◽  
Intrinsic Stiffness

Kozlovskaya et al. [1] and Grigoriev et al. [2] showed that enormous loss of muscle stiffness (atonia) develops in humans under true (space flight) and simulated microgravity conditions as early as after the first days of exposure. This phenomenon is attributed to the inactivation of slow motor units and called reflectory atonia. However, a lot of evidence indicating that even isolated muscle or a single fiber possesses substantial stiffness was published at the end of the 20th century. This intrinsic stiffness is determined by the active component, i.e. the ability to form actin-myosin cross-bridges during muscle stretch and contraction, as well as by cytoskeletal and extracellular matrix proteins, capable of resisting muscle stretch. The main facts on intrinsic muscle stiffness under conditions of gravitational unloading are considered in this review. The data obtained in studies of humans under dry immersion and rodent hindlimb suspension is analyzed. The results and hypotheses regarding reduced probability of cross-bridge formation in an atrophying muscle due to increased interfilament spacing are described. The evidence of cytoskeletal protein (titin, nebulin, etc.) degradation during gravitational unloading is also discussed. The possible mechanisms underlying structural changes in skeletal muscle collagen and its role in reducing intrinsic muscle stiffness are presented. The molecular mechanisms of changes in intrinsic stiffness during space flight and simulated microgravity are reviewed.

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