Foundations of Vectorial Metabolism and Osmochemistry

2004 ◽  
Vol 24 (4-5) ◽  
pp. 386-435 ◽  
Author(s):  
Peter D. Mitchell

Chemical transformations, like osmotic translocations, are transport processes when looked at in detail. In chemiosmotic systems, the pathways of specific ligand conduction are spatially orientated through osmoenzymes and porters in which the actions of chemical group, electron and solute transfer occur as vectorial (or higher tensorial order) diffusion processes down gradients of total potential energy that represent real spatially directed fields of force. Thus, it has been possible to describe classical bag-of-enzymes biochemistry as well as membrane biochemistry in terms of transport. But it would not have been possible to explain biological transport in terms of classical transformational biochemistry or chemistry. The recognition of this conceptual asymmetry in favour of transport has seemed to be upsetting to some biochemists and chemists; and they have resisted the shift towards thinking primarily in terms of the vectorial forces and co-linear displacements of ligands in place of their much less informative scalar products that correspond to the conventional scalar energies. Nevertheless, considerable progress has been made in establishing vectorial metabolism and osmochemistry as acceptable biochemical disciplines embracing transport and metabolism, and bioenergetics has been fundamentally transformed as a result.

1991 ◽  
Vol 11 (6) ◽  
pp. 297-346 ◽  
Author(s):  
Peter Mitchell

Chemical transformations, like osmotic translocations, are transport processes when looked at in detail. In chemiosmotic systems, the pathways of specific ligand conduction are spatially orientated through osmoenzymes and porters in which the actions of chemical group, electron and solute transfer occur as vectorial (or higher tensorial order) diffusion processes down gradients of total potential energy that represent real spatially-directed fields of force. Thus, it has been possible to describe classical bag-of-enzymes biochemistry as well as membrane biochemistry in terms of transport. But it would not have been possible to explain biological transport in terms of classical transformational biochemistry or chemistry. The recognition of this conceptual asymmetry in favour of transport has seemed to be upsetting to some biochemists and chemists; and they have resisted the shift towards thinking primarily in terms of the vectorial forces and co-linear displacements of ligands in place of their much less informative scalar products that correspond to the conventional scalar energies. Nevertheless, considerable progress has been made in establishing vectorial metabolism and osmochemistry as acceptable biochemical disciplines embracing transport and metabolism, and bioenergetics has been fundamentally transformed as a result.


2006 ◽  
Vol 258-260 ◽  
pp. 63-67
Author(s):  
V.M. Chumarev ◽  
V.P. Maryevich ◽  
V.A. Shashmurin

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering which spatially divides the reagents on the surface in the same way as in the oxidation and sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that interaction of metals with calcium and sodium sulfates will be determined not by the actual chemical reaction properly but by the diffusion transport processes.


2016 ◽  
Vol 25 (11) ◽  
pp. 1650096
Author(s):  
S. A. Seyyedi

The effects of the projectile deformation and orientation on the total potential characteristic have been studied for the reactions between weakly bound nucleus, 9Be, as the projectile and different targets. In this paper, the double-folding model is used to calculate the nuclear potentials and deformation of projectile included. It is shown that applying the deformation effects can modify the potential barrier height and depth in the interior regions of the potential. It is also shown that the gradient variation of the potential barrier height is linearly increased when the angle between the projectile and the target nuclei increases. The rate of the variation is constant in different reactions with 9Be. In order to study the possible effect of these deformation dependent potentials, application is made in the calculation of cross-sections of the different reactions. It is observed that the deformation and orientation are of important role in the dynamics of such reactions and improve the agreement with the experimental results.


2005 ◽  
Vol 11 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Ran Nathan ◽  
Nir Sapir ◽  
Ana Trakhtenbrot ◽  
Gabriel G. Katul ◽  
Gil Bohrer ◽  
...  

2019 ◽  
Vol 116 (36) ◽  
pp. 17683-17689 ◽  
Author(s):  
Daniela E. Blanco ◽  
Bryan Lee ◽  
Miguel A. Modestino

Organic electrosynthesis can transform the chemical industry by introducing electricity-driven processes that are more energy efficient and that can be easily integrated with renewable energy sources. However, their deployment is severely hindered by the difficulties of controlling selectivity and achieving a large energy conversion efficiency at high current density due to the low solubility of organic reactants in practical electrolytes. This control can be improved by carefully balancing the mass transport processes and electrocatalytic reaction rates at the electrode diffusion layer through pulsed electrochemical methods. In this study, we explore these methods in the context of the electrosynthesis of adiponitrile (ADN), the largest organic electrochemical process in industry. Systematically exploring voltage pulses in the timescale between 5 and 150 ms led to a 20% increase in production of ADN and a 250% increase in relative selectivity with respect to the state-of-the-art constant voltage process. Moreover, combining this systematic experimental investigation with artificial intelligence (AI) tools allowed us to rapidly discover drastically improved electrosynthetic conditions, reaching improvements of 30 and 325% in ADN production rates and selectivity, respectively. This powerful AI-enhanced experimental approach represents a paradigm shift in the design of electrified chemical transformations, which can accelerate the deployment of more sustainable electrochemical manufacturing processes.


Author(s):  
Sansit Patnaik ◽  
John P. Hollkamp ◽  
Fabio Semperlotti

Variable-order fractional operators were conceived and mathematically formalized only in recent years. The possibility of formulating evolutionary governing equations has led to the successful application of these operators to the modelling of complex real-world problems ranging from mechanics, to transport processes, to control theory, to biology. Variable-order fractional calculus (VO-FC) is a relatively less known branch of calculus that offers remarkable opportunities to simulate interdisciplinary processes. Recognizing this untapped potential, the scientific community has been intensively exploring applications of VO-FC to the modelling of engineering and physical systems. This review is intended to serve as a starting point for the reader interested in approaching this fascinating field. We provide a concise and comprehensive summary of the progress made in the development of VO-FC analytical and computational methods with application to the simulation of complex physical systems. More specifically, following a short introduction of the fundamental mathematical concepts, we present the topic of VO-FC from the point of view of practical applications in the context of scientific modelling.


2016 ◽  
Author(s):  
Johannes Kulenkampff ◽  
Marion Gründig ◽  
Abdelhamid Zakhnini ◽  
Johanna Lippmann-Pipke

Abstract. Transport processes in geomaterials can be observed with input-output experiments, which yield no direct information on the impact of heterogeneities, or they can be assessed by model simulations based on structural imaging with µCT. Positron emission tomography (PET) provides an alternative experimental observation method which directly and quantitatively yields the spatiotemporal distribution of tracer concentration. Process observation with PET benefits from its extremely high sensitivity together with a resolution that is acceptable in relation to standard drill core sizes. We strongly recommend applying high-resolution PET scanners in order to achieve a resolution in the order of 1 mm. We discuss the particularities of PET applications in geoscientific experiments (GeoPET), which essentially are due to high material density. Although PET is rather insensitive to matrix effects, mass attenuation and Compton scattering have to be corrected thoroughly in order to derive quantitative values. Examples of process monitoring of advection and diffusion processes with GeoPET are illustrating the procedure and the experimental conditions, as well as the benefits and limits of the method.


2007 ◽  
Vol 123 (2) ◽  
pp. 685-695 ◽  
Author(s):  
Vishnu Baba Sundaresan ◽  
Christopher Homison ◽  
Lisa M. Weiland ◽  
Donald J. Leo

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