Complex interrelationships

The mechanism by which nonkey components affect a given separation is more complex in practice than the broad arguments presented here. There are complex interrelationships between the volatility of the key and nonkey components, etc. Although the argument presented is thus not rigorous, it is broadly correct. 

The induction of systemic toxicity may involve a variety of complex interrelationships between the absorbed parent material, any conversion products, and their concentration and distribution in body tissues and fluids. The general pathway that a material may foUow after its absorption is shown schematically in Eigure 2. 

In the CNS there are many forms of neuronal organisation. One neuron can have many synaptic inputs and a multiplicity of NTs and NT effects are utilised within a complex interrelationship of neurons. There are also positive and negative feedback circuits as well as presynaptic influences all designed to effect changes in excitability and frequency of neuronal firing, i.e. patterns of neuronal discharge. 

A more recent study, which measured three established markers of free-radical activity in addition to serum ascorbic acid in two groups of elderly diabetic patients (with and without retinopathy), found no significant differences in any of the markers between patients and age-matched controls despite significant depletion of ascorbic acid in patients with diabetes, especially those with retinopathy (Sinclair et al., 1992). These rather paradoxical findings suggest the existence of a complex interrelationship between the levels of individual antioxidant molecules in cells and tissues. 

Future research should also focus its attention on the factors/mechanisms that regulate free-radical activity in vivo. The complex interrelationship between cellular and extracellular levels of antioxidants needs to be clarified, and factors that govern the synthetic rate of the scavenging enzymes, for example, SOD or catalase will provide further insight into cellular redox control. 

It is seen that all the variables, required for the solution of any one equation block are obtained as results from other blocks. The information flow diagram thus emphasises the complex interrelationship of this very simple problem. 

The mechanism by which nonkey components affect a given separation is more complex in practice than the broad arguments presented here. There are complex interrelationships between the volatility of the key and nonkey components, and so on. Also, it is often the case that the distillations system has constraints to prevent certain heat integration opportunities. Such constraints will often present themselves as constraints over which the pressure of the distillation columns will operate. For example, it is often the case that the maximum pressure of a distillation column is restricted to avoid decomposition of material in the reboiler. This is especially the case when reboiling high molar mass material. Distillation of high molar mass material is often constrained to operate under vacuum conditions. Clearly, if the pressure of the distillation column is constrained, then this restricts the heat integration opportunities. Another factor that can create... 

Thus our rather small set of samples from a few selected areas of the U.S.A. shows a dispersion of some aspects of liquefaction behavior that is evidently associated with differences in the geology and geochemistry of the sample. Still more would we expect many sets of complex interrelationships between coal characteristics to emerge had we had a sufficiently large world-wide sample base to work with. 

Characterisation covers a wide field of science and technology and interacts from the synthesis stage through the analysis of structure to the determination of properties. Characterisation allows one to observe, control and model (including "closed-loop" backward interaction) all the complex interrelationships of materials science. 

The research, development, and acquisition (RDA) process for vaccines is extraordinarily complex, highly technical and regulated, and difficult to articulate to those outside the vaccine business in a manner that enables them to grasp the complexity, interrelationship and dependencies of the steps in the process, let alone the overall problems encountered in getting a potential vaccine from... 

As as been pointed out in Boxes 3-C and 17-C, the use of 13C and other isotopic tracers together with NMR and mass spectroscopy have provided powerful tools for understanding the complex interrelationships among the various interlocking pathways of metabolism. In Box 17-C the application of 13C NMR to the... 

It is beyond the scope of this discussion to consider the complex interrelationships between these species in detail, but a clear account is given by Wikstrom et al1299 Instead, a summary of the intermediates formed in the reduction of dioxygen will be presented. It is probable that not all of the many intermediates observed are of mechanistic significance. 

Complex interrelationships between age-associated illnesses such as vascular disease and AD indicate that biological and genetic pathways may be worthy of examination in centenarian populations to provide insights into human longevity. This is also borne out by the involvement of lipoprotein... 

To provide an overview chemical constitution and synthesis are combined in this section. The various application media for metal-complex dyes are a further ordering principle, which generates overlap of some sections with reactive dyes (Section 3.1), leather dyes (Section 5.1), and paper dyes (Section 5.3), demonstrating the typically complex interrelationship of constitution and application of dyes. 

Salicylic acid at 25 pM strongly inhibited ethylene formation from ACC in cell suspension cultures, and a number of other benzoic acid derivatives suppress ethylene production at higher concentrations.44 The complex interrelationship of phenolic acids with phytohormones deserves further investigation. The early stage of seedling growth is very sensitive to phenolic acids, and this is a prime time in hormone-mediated growth responses. 

Saturated four-carbon hydrocarbons (butanes) occur in natural petroleum products such as crude oil and the heavy vapors in wet natural gas. The saturated C4s are also produced from other hydrocarbons during the various petroleum refining processes. The butylenes— unsaturated C4s—do not occur in nature, but are derived from butanes or other hydrocarbons either deliberately or as by-products. The complex interrelationships of C4 hydrocarbons, including their production and use, are described in Fig. 10.27. 

There is not much that needs to be said here. Whatever policy is chosen, the cost of the policy is always an issue. Relative costs between policies are often difficult to calculate due to the complex interrelationships involved. For example, the cost of a full recycle policy must be measmed comparing the costs of building and operating reprocessing facilities and new reactors with the alternative of building and operating new... 

In considering creep behavior as a measure of physical or chronological age, one finds that the measurement is not simple and is affected by many factors. A rather complex interrelationship exists among the strain... 

The complex interrelationships of three types of chemical equilibria, namely oxidation-reduction, hydrolysis, and complexa-tion, as well as polymerization, a nonequilibrium process, determine the nature and speciation of plutonium in aqueous environmental systems. This paper presents a selective, critical review of the literature describing these processes. Although most research has been conducted under non-environmental conditions— that is, macro concentrations of plutonium and high acidities—the results in some cases are applicable to environmental conditions. In other cases the behavior is different, however, and care should always be exercised in extrapolating macro data to environmental conditions. 

It proved difficult to definitively demonstrate CRH synthesis from immune cells, although numerous studies provided evidence this does happen (Aird et al., 1993 Ekman et al., 1993). Eventually it became clear that regulation of CRH synthesis and release in immune cells differs from that in hypothalamic neurons. While immune cells may synthesize and release much smaller concentrations of CRH and other neuroimmune peptides, and although their release may require de novo synthesis, an inherently slow process, the fact that immune cells release these hormones locally in the target area compensates for both of these factors to some extent. These data indicating site and tissue specific effects of CRH, sometimes even contradictory effects, point to the complex interrelationship betw een the nervous, endocrine and immune systems, an interaction that has yet to be deciphered completely. 

A growing number of oestrogens and related metabolites in various body fluids, e.g. [234,235] and in placental tissue [236] have been identified. In the latter study, care was taken to remove as much foetal blood as possible to minimise contamination of the extracts. In addition to the three principal oestrogens, oestrone, oestradiol and oestriol, other unconjugated oestriols, 16-hydroxyoestrone, 16-oxo-oestradiol, 2-methoxyoestrone, 16-epioestratriol, 17-epioestriol and 15a-hydroxy-oestrone were identified and semiquantitated. These results coupled with the levels of foetal and maternal oestrogens help to establish the complex interrelationships in steroid metabolism obtained in the mother, foetus and placenta. 

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