Modelling Interpretation of the Kinetics of Metabolic Processes

2000 ◽  
pp. 305-328 ◽  
Author(s):  
S. Bastianoni ◽  
C. Bonechi ◽  
A. Gastaldelli ◽  
S. Martini ◽  
C. Rossi
Keyword(s):  
Metabolic Processes ◽  
Kinetics Of

The effect of heterotrophic yield on the assessment of the correction factor for anoxic growth

1996 ◽  
Vol 34 (5-6) ◽  
pp. 67-74 ◽  
Author(s):  
D. Orhon ◽  
S. Sözen ◽  
N. Artan
Keyword(s):  
Correction Factor ◽  
Domestic Sewage ◽  
Yield Coefficient ◽  
Heterotrophic Growth ◽  
Metabolic Processes ◽  
Anoxic Conditions ◽  
Industrial Wastewaters ◽  
Systems Modelling ◽  
Kinetics Of ◽  
Very High

For single-sludge denitrification systems, modelling of anoxic reactors currently uses the kinetics of aerobic heterotrophic growth together with a correction factor for anoxic conditions. This coefficient is computed on the basis of respirometric measurements with the assumption that the heterotrophic yield remains the same under aerobic and anoxic coditions. The paper provides the conceptual proof that the yield coefficient is significantly lower for the anoxic growth on the basis of the energetics of the related metabolic processes. This is used for the interpretation of the very high values for the correction factor experimentally determined for a number of industrial wastewaters. A default value for the anoxic heterotrophic yield coefficient is calculated for domestic sewage and compatible wastewaters and proposed for similar evaluations.

Structural Macrokinetics of Biomimetic Processes in Artificial Cells

2018 ◽  
Author(s):  
Oleg Gradov ◽  
Margaret Gradova
Keyword(s):  
Soft Matter ◽  
Reaction Diffusion ◽  
Cell Ultrastructure ◽  
Cellular Respiration ◽  
Metabolic Processes ◽  
Physico Chemical ◽  
Dynamic Membranes ◽  
Diffusion Mechanisms ◽  
Kinetics Of ◽  
Metabolic Phenomena

It is known that all cytophysiological processes occur on the cell ultrastructure, which is a heterogeneous (heterophase) medium. So the kinetics of metabolic processes should be considered as a structural macrokinetics of this partially ordered medium (soft matter). Our model reproduces the structural-macrokinetic aspect of a number of metabolic phenomena, based on the physico-chemical analogies with the biological cell. Thus, the semipermeability of bioorganic membranes is simulated by semiconductive polymer inorganic dynamic membranes, exergonic chemoosmotic redox processes are equivalent to cellular respiration, biomimetic self-oscillating reactions are analogues of oscillatory metabolic processes and finally the structure formation in these models is also provided by reaction-diffusion mechanisms.

A modellistic view of the kinetics of metabolic processes: differences in the glucose and xylose degradation pathway

1999 ◽  
Vol 310 (1-2) ◽  
pp. 38-42 ◽  
Author(s):  
Simone Bastianoni ◽  
Alessandro Donati ◽  
Amalia Gastaldelli ◽  
Nadia Marchettini ◽  
Silvia Martini ◽  
...  
Keyword(s):  
Degradation Pathway ◽  
Metabolic Processes ◽  
Kinetics Of

scholarly journals Structural Macrokinetics of Biomimetic Processes in Artificial Cells

2018 ◽  
Author(s):  
Oleg Gradov ◽  
Margaret Gradova
Keyword(s):  
Soft Matter ◽  
Reaction Diffusion ◽  
Cell Ultrastructure ◽  
Cellular Respiration ◽  
Metabolic Processes ◽  
Physico Chemical ◽  
Dynamic Membranes ◽  
Diffusion Mechanisms ◽  
Kinetics Of ◽  
Metabolic Phenomena

It is known that all cytophysiological processes occur on the cell ultrastructure, which is a heterogeneous (heterophase) medium. So the kinetics of metabolic processes should be considered as a structural macrokinetics of this partially ordered medium (soft matter). Our model reproduces the structural-macrokinetic aspect of a number of metabolic phenomena, based on the physico-chemical analogies with the biological cell. Thus, the semipermeability of bioorganic membranes is simulated by semiconductive polymer inorganic dynamic membranes, exergonic chemoosmotic redox processes are equivalent to cellular respiration, biomimetic self-oscillating reactions are analogues of oscillatory metabolic processes and finally the structure formation in these models is also provided by reaction-diffusion mechanisms.

scholarly journals Entropic regulation of dynamical metabolic processes

2019 ◽  
Author(s):  
Stephan O. Adler ◽  
Edda Klipp
Keyword(s):  
Energy Dissipation ◽  
Open Systems ◽  
Reaction System ◽  
High Energy ◽  
Steady States ◽  
Metabolic Processes ◽  
Cellular Processes ◽  
Metabolic Systems ◽  
Biotechnological Processes ◽  
Kinetics Of

AbstractLife depends on the input of energy, either directly provided by sunlight or in form of high-energy matter. The rules and conditions for the conversion of chemical or electromagnetic energy into living structure and all the processes related with life are governed by the laws of thermodynamics. Hence, to understand the potential and the limitations of cell growth and metabolism, it is unavoidable to take these laws into account. During the last years, systems biology has developed many mathematical models aiming to describe steady states and dynamic behavior of cellular processes in qualitative and quantitative terms. The validity of the model predictions depends strongly on whether the model formulation is in agreement with the laws of physics, chemistry, and, specifically, thermodynamics.Here, we review basic principles of thermodynamics for equilibrium and non-equilibrium processes as well as for closed and open systems as far as they concern metabolic processes, especially in their dynamics. We illustrate the application of thermodynamic laws for some practical cases that are currently intensively studied in systems and computational biology. Specifically, we will discuss the concept of entropy production and energy dissipation for isolated and open systems and its interpretation for the feasibility of biological processes, especially metabolism. We demonstrate that steady states of metabolic systems cannot show energy dissipation, while in dynamical modes entropy of the system can be both increased or decreased, depending on the type of perturbation and the kinetics of the reaction system. These findings are very important for biotechnological processes where energy dissipation should be limited, but also for analysis of healthy and diseased cellular metabolism.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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