Natural produces

A process based on saponification of ethylene—acrylate ester copolymers has been practiced commercially in Japan (29). The saponification naturally produces fully neutralized polymer, and it is then necessary to acidify in order to obtain a pardy neutralized, melt-processible product. Technology is described to convert the sodium ionomer produced by this process to the zinc type by soaking pellets in zinc acetate solution, followed by drying (29). 

Half of all sodium sulfate made is actually a waste by-product and may even present a disposal problem. For this reason, manufacturers sell it at a low price to ensure quick sale. This in turn sets the price for all naturally produced sodium sulfate and tends to keep values low. Figure 3 shows price fluctuations from 1970 to 1995. 

Tetraterpenes. Carotenoids make up the most important group of C q terpenes and terpenoids, although not all carotenoids contain 40 carbon atoms. They are widely distributed in plant, marine, and animal life. It has been estimated that nature produces about 100 million t/yr of carotenoids synthetic production amounts to several hundred tons per year (207,208). 

The biochemical industiy derives its products from two primaiy sources. Natural produces are yielded by plants, animal tissue, and fluids, and obtained via fermentation from bacteria, molds and fungi, and from man imahan cells. Products can also be obtained by recombinant... 

The term endocrine disrupter (ED) has tended to be used for those chemicals which act specifically at the level of the hormone receptor present in the target cells of various organs. Such chemicals may either mimic the action of the natural hormone (agonistic activity) or are sufficiently similar in molecular shape to the naturally produced hormone to interfere with the interaction between the hormone and receptor, thus blocking or impeding the activation of the receptor (antagonsitic activity). Such effects may occur at very low concentrations (as with the endogenous hormone), compared with the concentrations normally required to elicit the more traditional toxic effects attributed to chemicals. Recently,... 

Within the constraints of this article it is impossible to be comprehensive in the coverage of the subject matter, in terms of the chemicals involved and in the widely varying practices and areas of the world in which the title compounds are ingested by farmed animals. This account is, however, intended to give an overview, citing some relevant examples, of the beneficial and adverse effects, in animals and on the environment, of man-made compounds and naturally produced compounds in extensive and commercial production systems. 

The effects of drugs in animals are usually concentration dependent and are also often animal species and site-of-action dependent " " " thus the compounds may be present naturally in diets at low levels and produce no obvious adverse effects, either on the animal, gut microflora, meat, milk or eggs. The main purpose of the use of drugs in animal feeds is to improve the animal health and welfare and often to improve growth at minimum cost to the producer.In the case of naturally produced compounds that may occur in the feedstuff s of animals, these compounds may impair animal health and performance as well as cause im-... 

A wide variety of animal species are subjected to the administration of drugs during their lifetime.The various animal species can encounter drugs and other dietary additives by different routes and this is dependent on the environment in which they are kept. Intensively reared animals tend to have considerable consistency in the components of their diets and thus are much less likely to encounter the range of naturally produced compounds that extensively produced animals encounter. The desire for less expensive dietary constituents and increased efficiency of use has induced feed manufacturers and producers to add enzyme supplements to diets of most farmed animals to reduce the negative effects of indigestible dietary carbohydrates, refactory proteins and unavailable minerals such as phosphorus. This use of dietary additives to improve nutrient utilization and environmental consequences of feeding animals intensively has been the subject of intense research activity in the last five years. " The... 

Nature produces a tremendous amount of methyl aleohol, simply by the fermentation of wood, grass, and other materials made to some degree of eellulose. In faet, methyl aleohol is known as wood aleohol, along with names sueh as wood spirits and methanol (its proper name the proper names of all aleohols end in -ol). Methyl aleohol is a eolorless liquid with a eharaeteristie aleohol odor. It has a flash point of 54°F, and is highly toxie. It has too many eommereial uses to list here, but among them are as a denaturant for ethyl alcohol (the addition of the toxie ehemieal methyl aleohol to ethyl aleohol in order to form denatured aleohol), antifreezes, gasoline additives, and solvents. No further substitution of hydroxyl radieals is performed on methyl aleohol. 

Streptomyces aureofaciens naturally produces chlortetracydine. This has the structure... 

A rigorous approach to studies of naturally produced toxic materials would involve isolation of the compounds in pure form and demonstration that the substances isolated were actually responsible for the observed inhibition. Synthesis and confirmation of activity of the synthetic vs. the natural material may also be required. These criteria have been met in relatively few cases. Unfortunately, studies with naturally occurring inhibitors have been made primarily by plant physiologists without sufficient assistance from chemists. 

Air pollution is principally a problem in urban and heavily industrialized areas, where the flow of clean air from surrounding areas is insufficient to disperse the accumulation. Motor vehicles account for more than 50% of the man-made emissions of carbon monoxide, hydrocarbons, and nitrogen oxides (4). More than half of the U.S. annual trillion vehicle miles are driven in urban areas (5). Nature produces much more pollutants than all man-made sources, but natural emissions are widely dispersed and do not contribute heavily to urban pollution problems (6, 7). 

M ale and female hormones play a vital role because they aid in development and maintenance of secondary sex characteristics and are necessary for human reproduction. Although hormones are naturally produced by die body, administration of a male or female hormone may be indicated in the treatment of certain disorders, such as inoperable breast cancer, male hypogonadism, and male or female hormone deficiency. Hormones also are used as contraceptives and for treating the symptoms of menopause... 

Estrogens and progestins (combination oral contraceptives) are used as oral contraceptives. There are three types of estrogen and progestin combination oral contraceptives monophasic, biphasic, and triphasic. The monophasic oral contraceptives provide a fixed dose of estrogen and progestin throughout the cycle The biphasic and triphasic oral contraceptives deliver hormones similar to the levels naturally produced by the body (Table 52-1). 

Smaller bore diameters naturally produce slugs of smaller diameter [31,97]. Typically, a smaller length can also be generated thereby. As a consequence, internal circulation in the slug and specific interface between the slugs are increased. It is assumed that the impact of the increase in internal circulation on mass transfer/ reaction processing is generally more dominant. 

L-tryptophan is a naturally-produced, natural amino acid used as a dietary supplement. Samples from one manufacturer were found to be contaminated by trace amounts of another naturally occurring compound — l,l -ethylidene bis-[i.-tryptophan]. The latter compound appears to have been responsible for causing a number of deaths and additional cases of chronic eosinophilia-myalgia,111 some of which might have been prevented had there... 

Some insulating oxides become semiconducting by doping. This can be achieved either by inserting certain heteroatoms into the crystal lattice of the oxide, or more simply by its partial sub-stoichiometric reduction or oxidation, accompanied with a corresponding removal or addition of some oxygen anions from/into the crystal lattice. (Many metal oxides are, naturally, produced in these mixed-valence forms by common preparative techniques.) For instance, an oxide with partly reduced metal cations behaves as a n-doped semiconductor a typical example is Ti02. 

As mentioned in Section 6.9.3, nature produces the minerals terlinguaite (Hg3)Hg02Cl261-63 and kuznetsovite (Hg3)As04Cl,64-66 both with the lriangulo-l Ig341 entities in which the Hg atoms formally possess the oxidation number +4/3 in the former compound the Hg Hg bonds are the... 

Most polymers used in oil field operations and resource recovery are synthetic. The man-made materials in common use are polyO-amidoethylene) ( = polyacrylamide ), poly( 1-amidoethylene-r-( sodium 1-carboxylatoethylene ) ( = partially hydrolyzed polyacrylamide ), poly(l-amidoethylene-r-( sodium 1-(2-methylprop-1N-yl-1-sulfonate)amidoethylene) (AMPS-acrylamide copolymer), and xanthan gum. Xanthan gum is a synthetic because no one finds a pool or river contaminated with Xanthomonas compestris that experiences the right sequence of solute to naturally produce the exocellular gum polymer. A fermenter is a man made object, a tree is not. 

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