Association closed

Corrosion associated with the action of micro-organisms present in the corrosion system. The biological action of organisms which is responsible for the enliancement of corrosion can be, for instance, to produce aggressive metabolites to render the environment corrosive, or they may be able to participate directly in the electrochemical reactions. In many cases microbial corrosion is closely associated with biofouling, which is caused by the activity of organisms that produce deposits on the metal surface. 

Although no chemical reaction occurs, measurements of the freezing point and infra-red spectra show that nitric acid forms i i molecular complexes with acetic acid , ether and dioxan. In contrast, the infrared spectrum of nitric acid in chloroform and carbon tetrachloride - is very similar to that of nitric acid vapour, showing that in these cases a close association with the solvent does not occur. 

Vitamin E acetate [58-95-7] serves primarily as an antioxidant and is closely associated with selenium. Vitamin E usually is present in... 

Fluorspar deposits ate commonly epigenetic, ie, the elements moved from elsewhere into the country rock. For this reason, fluorine mineral deposits ate closely associated with fault 2ones. In the United States, significant fluorspar deposits occur in the Appalachian Mountains and in the mountainous regions of the West, but the only reported commercial production in 1993 was from the faulted carbonate rocks of Illinois. 

Immunoaffinity chromatography utilizes the high specificity of antigen—antibody interactions to achieve a separation. The procedure typically involves the binding, to a soHd phase, of a mouse monoclonal antibody which reacts either directly with the protein to be purified or with a closely associated protein which itself binds the product protein. The former approach has been appHed in the preparation of Factor VIII (43) and Factor IX (61) concentrates. The latter method has been used in the preparation of Factor VIII (42) by immobilization of a monoclonal antibody to von WiHebrand factor [109319-16-6] (62), a protein to which Factor VIII binds noncovalenfly. Further purification is necessary downstream of the immunoaffinity step to remove... 

With these waste-minimization techniques, methanol synthesis is relatively clean, and poses no unique environmental hazards. The need for environmental controls is more closely associated with the synthesis gas generation process. 

The resultant slag, a complex mixture of titanates, may contain 70—85% Ti02- The slag route is particularly useful when ilmenite is closely associated with haematite, from which it cannot economically be separated mechanically. Because the iron content of the slag is low, its use reduces the quantity of iron sulfate in the Hquid effluent of sulfate process plants. Slag used as a feedstock for TiCl production must be low in magnesium and calcium. A variety of other ilmenite beneficiation or synthetic mtile processes have been pursued, primarily to provide alternative chloride process feedstocks. Low grade ilmenite... 

Cadmium occurs primarily as sulfide minerals ia ziac, lead—ziac, and copper—lead—ziac ores. Beneftciation of these minerals, usually by flotation (qv) or heavy-media separation, yields concentrates which are then processed for the recovery of the contained metal values. Cadmium follows the ziac with which it is so closely associated (see Zinc and zinc alloys see also Copper Lead). 

In the bacterial reaction center the photons are absorbed by the special pair of chlorophyll molecules on the periplasmic side of the membrane (see Figure 12.14). Spectroscopic measurements have shown that when a photon is absorbed by the special pair of chlorophylls, an electron is moved from the special pair to one of the pheophytin molecules. The close association and the parallel orientation of the chlorophyll ring systems in the special pair facilitates the excitation of an electron so that it is easily released. This process is very fast it occurs within 2 picoseconds. From the pheophytin the electron moves to a molecule of quinone, Qa, in a slower process that takes about 200 picoseconds. The electron then passes through the protein, to the second quinone molecule, Qb. This is a comparatively slow process, taking about 100 microseconds. 

The antigen-binding site is formed by close association of the hypervariable regions from both heavy and light chains... 

As will be seen from curves A, B and C of Figure 9.1, the softening point of an amorphous polymer, i.e. the temperature at which the modulus drops catastrophically, is closely associated with the T. (Such softening does not of course occur in highly cross-linked polymers, as in type D, unless degradation also takes place.)... 

Thus, in contrast to an ionization process from a neutral substrate, which initially generates an intimate ion pair, deamination reactions generate a cation which does not have an anion closely associated with it. Furthermore, the leaving group, molecular nitrogen, is very stable so that little, if any, nutleophilic participation is needed for bond cleavage. The... 

Energy is a key issue and is closely associated with the environment. Global environmental issues must be addressed, where the energy chain from resources to end users is of vital importance. 

Other members of this sub-group, usually more closely associated with berberine in distribution, or in structure, or both, and therefore dealt with in the Berberis group, are canadine (p. 338), capaurine (p. 339), cheilanthifoline (p. 339), ophiocarpine (p. 338), sinactine (p. 338), tetra-hydroshobakunine (p. 340) and tetrahydroworenine (p. 344). 

Bebeerine and its allies (p. 363) are also derived from menispermaceous plants, but as their botanical source needs attention in some detail, and in view of their importance as close associates of the curare alkaloids, they are dealt with separately at the end of this section. 

Cub and the iron atom of cytochrome Og are also situated close to each other and are thought to share a ligand, which may be a cysteine sulfur (Figure 21.19). This closely associated pair of metal ions is referred to as a buiuclear center. 

Another phenomenon that is closely associated with acid-base equilibria is the so-called hydrolysis of metal cations in aqueous solution, which is probably better considered as the protolysis of hydrated cations, e.g. ... 

Despite their chemical similarity, Li, Na and K are not closely associated in their occurrence, mainly because of differences in size (see... 

The osmophoric elements are all closely associated in the periodic table and are therefore likely to have a fundamental common characteristic and the property of varying valence is one of their common characteristics, whereas it seldom occurs with the non-osmophoric elements. 

There is an isomeric and closely associated alcohol, phenyl-methyl carbinol, CgH5CH OH)CHg, known to chemists. This is a liquid of different odour, but which is not used very much in synthetic perfumery. It is an oil boiling at 203°, and forms an acetate which is found naturally in essential oil of gardenia. This ester is of use in blending perfumes of this type of flower. 

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