scholarly journals Viscoadaptation controls intracellular reaction rates in response to heat and energy availability

2019 ◽  
Author(s):  
Laura Persson ◽  
Vardhaan S. Ambati ◽  
Onn Brandman
Keyword(s):  
Cellular Response ◽  
Reaction Rates ◽  
Acute Response ◽  
Cellular Environment ◽  
Diffusion Controlled ◽  
Intracellular Diffusion ◽  
Response To Temperature ◽  
And Diffusion ◽  
Tunable Property ◽  
Multiple Conditions

Summary/AbstractCells must precisely orchestrate thousands of reactions in both time and space. Yet reaction kinetics are highly dependent on uncontrollable environmental conditions such as temperature. Here, we report a novel mechanism by which budding yeast influence reaction rates through adjustment of intracellular viscosity. This “viscoadaptation” is achieved by production of two carbohydrates, trehalose and glycogen, which combine to create a more viscous cellular environment in which biomolecules retain solubility. We demonstrate that viscoadaptation functions as both an acute response to temperature increase as well as a homeostatic mechanism, allowing cells grown at temperatures spanning from 22°C to 40°C to maintain equivalent rates of intracellular diffusion and diffusion-controlled chemical reactions. Multiple conditions that lower ATP trigger viscoadaptation, suggesting that viscoadaptation may be a general cellular response to low energy. Viscoadaptation reveals viscosity to be a tunable property of cells through which they can regulate diffusion-controlled processes dynamically in response to a changing environment.

Solvent Structure Effects and Diffusion Control in the Reaction Between Solvated Electrons and Solvated Protons in Alcohols and Water

1972 ◽  
Vol 50 (18) ◽  
pp. 3073-3075 ◽  
Author(s):  
K. N. Jha ◽  
G. L. Bolton ◽  
G. R. Freeman
Keyword(s):  
Reaction Rates ◽  
Diffusion Control ◽  
Solvent Structure ◽  
Solvated Electrons ◽  
Solvent Dependence ◽  
Diffusion Controlled ◽  
Water Effects ◽  
And Diffusion ◽  
Debye Equation

The rates of reactions 1 and 2 are diffusion controlled in alcohols[Formula: see text]In water reaction 1 is slower and reaction 2 (where RO− is HO−) is faster than one would estimate from the Debye equation for diffusion controlled reactions. The solvent dependence of the relative values of k1 and k2 is attributed to the solvent dependence of the structures of [Formula: see text] [Formula: see text] [Formula: see text] and H+ and RO− are strong solvent structure makers in alcohols and in water, whereas e− is a weak solvent structure maker in alcohols and a strong structure breaker in water. Effects of the solvent structure making and breaking properties of ions on their reaction rates have been proposed by Gurney and Frank.

Vacancy-Mediated Diffusion and Diffusion-Controlled Processes in Ordered Binary Intermetallics by Kinetic Monte Carlo Simulations

2021 ◽  
Vol 29 ◽  
pp. 95-115
Author(s):  
Rafal Kozubski ◽  
Graeme E. Murch ◽  
Irina V. Belova
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Simulation Studies ◽  
Self Diffusion ◽  
Monte Carlo Techniques ◽  
Diffusion Controlled ◽  
Kinetic Monte Carlo Simulations ◽  
Kinetic Effects ◽  
Kinetics Of ◽  
And Diffusion

We review the results of our Monte Carlo simulation studies carried out within the past two decades in the area of atomic-migration-controlled phenomena in intermetallic compounds. The review aims at showing the high potential of Monte Carlo methods in modelling both the equilibrium states of the systems and the kinetics of the running processes. We focus on three particular problems: (i) the atomistic origin of the complexity of the ‘order-order’ relaxations in γ’-Ni3Al; (ii) surface-induced ordering phenomena in γ-FePt and (iii) ‘order—order’ kinetics and self-diffusion in the ‘triple-defect’ β-NiAl. The latter investigation demonstrated how diverse Monte Carlo techniques may be used to model the phenomena where equilibrium thermodynamics interplays and competes with kinetic effects.

scholarly journals Electrochemical Behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones

2012 ◽  
Vol 9 (4) ◽  
pp. 1864-1874
Author(s):  
V. Nagaraju ◽  
R. Sreenivasulu ◽  
P. Venkata Ramana
Keyword(s):  
Electrochemical Behaviour ◽  
Reduction Process ◽  
Effect Of Solvent ◽  
Buffer Solutions ◽  
Diffusion Controlled ◽  
Controlled Potential Electrolysis ◽  
Dc Polarography ◽  
Controlled Potential ◽  
Ph Range ◽  
And Diffusion

The electrochemical behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones has been investigated at dme and gc electrodes in buffer solutions of pH 2.0, 4.0, 6.0, 8.0 and 10.0 using dc polarography and cyclic voltammetry and coulometry. The compounds exhibit one well defined wave in the entire pH range of study. The process is irreversible and diffusion controlled. Controlled potential electrolysis indicates the involvement of four electrons in the reduction process. The effect of solvent, cations and anions, temperature and substitutents on the mechanism of reduction has been studied. Based on the results obtained the mechanism of reduction has been suggested.

Refinement of Size Distributions for Primary Crystallizations

1997 ◽  
Vol 481 ◽  
Author(s):  
E. Pineda ◽  
T. Pradell ◽  
D. Crespo ◽  
N. Clavaguera ◽  
J. ZHU ◽  
...  
Keyword(s):  
Grain Size ◽  
Metastable Phase ◽  
Primary Crystallization ◽  
Controlled Growth ◽  
Diffusion Controlled ◽  
Average Grain Size ◽  
Soft Impingement ◽  
Single Grain ◽  
Kinetics Of ◽  
And Diffusion

ABSTRACTThe microstructure developed in primary crystallizations is studied under realistic conditions. The primary crystallization of an amorphous alloy is modeled by considering the thermodynamics of a metastable phase transition and the kinetics of nucleation and crystal growth under isothermal annealing. A realistic growth rate, including an interface controlled growth at the beginning of the growth of each single grain and diffusion controlled growth process with soft impingement afterwards is considered. The reduction in the nucleation rate due to the compositional change in the remaining amorphous matrix is also taken into account. The microstructures developed during the transformation are obtained by using the Populational KJMA method, from the above thermodynamic and kinetic factors. Experimental data of transformed fraction, grain density, average grain size, grain size distribution and other related parameters obtained from annealed metallic glasses are modeled.

scholarly journals Extrapolation and interpolation by time-scaling in systems with diffusion-controlled kinetics and first-order reaction rates.

1989 ◽  
Vol 37 (1) ◽  
pp. 47-60
Author(s):  
S.E.A.T.M. van der Zee ◽  
W.H. van Riemsdijk ◽  
J.J.M. van Grinsven
Keyword(s):  
Reaction Rates ◽  
Order Reaction ◽  
Management Tool ◽  
First Order ◽  
Physicochemical Processes ◽  
Time Scaling ◽  
Diffusion Controlled ◽  
Scaling Procedure ◽  
Exposure Variable ◽  
Scaling Rule

The interpolation or extrapolation in time of physicochemical processes from experimental data is often difficult. A theoretically derived time-scaling procedure using an exposure variable of the concentration integrated in time, with at most one adjustable parameter was applied successfully to three systems taken from metallurgical, agricultural and environmental engineering. This scaling rule is potentially useful as a research or management tool for systems that are too complex for mechanistic modelling. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Versatile electrochemical activation strategy for high-performance supercapacitor in a model of MnO2

2019 ◽  
Vol 7 (37) ◽  
pp. 21290-21298 ◽  
Author(s):  
Yaxiong Zhang ◽  
Yupeng Liu ◽  
Zhenheng Sun ◽  
Jiecai Fu ◽  
Situo Cheng ◽  
...  
Keyword(s):  
High Performance ◽  
Electrochemical Activation ◽  
Diffusion Controlled ◽  
And Diffusion ◽  
Charge Discharge

Electrochemical activation was used to boost surface- and diffusion-controlled capacitance of MnO2 by optimized charge–discharge cycling operations.

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