Product formation rates, influencing factors

Product formation rates have already been mentioned above as being influenced by environmental factors and by plant differentiation. Much previous research has approached the questions of environment and cell state empirically. Studies related to methods for optimizing product formation rates should be based, however, on a more fundamental understanding of cell biochemistry and physiology. 

We have seen that both the maintenance energy requirement and the P/O quotient of the process micro-organism influences the rate of product formation. In the following sections we will consider how these two factors can be determined, together with the maximum biomass yield. 

We here review the factors that control the kinetics of product formation through reaction at an active surface. This includes consideration of the availability of those adsorbed intermediates which participate in the rate-limiting step (this term is analogous to concentration in a homogeneous reaction) and the mobility of the same species, which may determine, or at least influence, the frequency of occurrence of the reaction situation. The discussion is given under three broadly interpreted general headings, between which there is considerable overlap. 

The study of indoor organic chemistry improves our understanding of personal exposure to both reactants and products. At present, our ability to make predictions or estimate past exposure is rudimentary. To improve, we need a more comprehensive evaluation of the mechanisms, rates and mediating factors in indoor environments. For example, it is well established that humidity tends to enhance ozone uptake on indoor surfaces, but how does this influence product formation Do C02 or NH3 influence transformative product yields as well as influencing the sorptive capacity of surfaces To what extent do occupants contribute to this chemistry through their choice of products, smoking or cooking ... 

The serum creatinine concentration is dependent on the input function, or formation rate, and output function, or elimination rate. Its formation rate depends on the zero-order production from creatine metabolism, as well as input from other sources such as dietary intake. Creatine metabolism is directly proportional to muscle mass therefore individuals with more muscle mass have a higher serum creatinine concentration at any given degree of kidney function than those with less muscle mass. Exercise is associated with an increase of approximately 10% in the serum creatinine concentration. As the result of minimal muscle mass patients who are cachectic will have very low serum creatinine concentrations, as do those with spinal cord injuries. " Elderly patients and those with poor nutrition may also have low serum creatinine concentrations (<1 mg/dL) secondary to decreased muscle mass. Other factors that influence the serum creatinine concentration include the dietary intake of creatine. During the cooking of meat, some creatine is converted to creatinine, which is rapidly absorbed following ingestion. 

Particle size affects the diffusion distance of the reactants and products. The longer distance of the diffusion, the bigger concentration gradient of reactant and products is. The effective diffusion coefficient of reactants and products is a complex coefficient. It is subject to influence by many factors, such as pore structure of catalyst, porosity of catalyst, and kinds of reactants and products. The reaction or formation rate of reactants and products is determined by reaction kinetics. Therefore, the research results of catalyst particle size, catalyst pore size, and diffiisivity of products should be discussed in detail. 

The liquid-phase oxidation of acrolein (AL), the reaction products, their routes of formation, reaction in the absence or presence of catalysts such as acetylacetonates (acac) and naphthenates (nap) of transition metals and the influence of reaction factors were discussed in an earlier paper (22). The coordinating state of cobalt acetylacetonate in the earlier stage of the reaction depends on the method of addition to the reaction system (25, 26). The catalyst, Co(acac)2-H20-acrolein, which was synthesized by mixing a solution of Co(acac)2 in benzene with a saturated aqueous solution, decreases the induction period of oxygen uptake and increases the rate of oxygen absorption. The acrolein of the catalyst coordinated with its cobalt through the lone pair of electrons of the aldehyde oxygen. Therefore, it is believed that the coordination of acrolein with a catalyst is necessary to initiate the oxidation reaction (10). 

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