Artificial processes

The differences and similarities of natural and artificial processes will be summarized and analyzed in the next sections. 

Enzymes Substrates Metal cations Products Occurrence 

RuBisCO ribulose Mg glucose C3-plants (also higher) 

Phosphoenolpyruvate carboxylase (PEPC) pyruvic acid Mg , Mn oxaloacetate C4-plants (mais, sugar cane, sorghum, etc.) 

Vitamine-K-dependent carboxylases first 10 glutamic acid residues in the N-terminal region of the precursor of prothrombin Mn y-carbo -glutamic acid  

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Commercial and Artificial Processing. Commercially, silkworm cocoons are extracted in hot soapy water to remove the sticky sericin protein. The remaining fibroin or stmctural sdk is reeled onto spools, yielding approximately 300—1200 m of usable thread per cocoon. These threads can be dyed or modified for textile appUcations. Production levels of sdk textiles in 1992 were 67,000 metric tons worldwide. The highest levels were in China, at 30,000 t, foUowed byJapan, at 17,000 t, and other Asian and Oceanian countries, at 14,000 t (24). Less than 3000 metric tons are produced annually in each of eastern Europe, western Europe, and Latin America almost no production exists in North America, the Middle East, or Africa. 1993 projections were for a continued worldwide increase in sdk textile production to 75,000 metric tons by 1997 and 90,000 metric tons by 2002 (24). 

Firstly, there are those cases where the hydrolysis takes place within the plant itself during the life of the plant, so that the essential oil is actually a product, in the free state, of the metabolic processes of the living plant and secondly, there are those cases where the glucoside is not decomposed except by artificial processes, independent of the life of the plant. 

Radioisotopes may occur in the earth naturally as primordial radioisotopes, formed when the planet was created, or be produced by natural or artificial processes. Most fast decaying primordial radioisotopes have long disappeared from the planet since the earth originated about 4.5 billion years ago, such isotopes have decayed and reached a final, stable form. The relatively few primordial radioisotopes still extant in the earth today, therefore, decay very slowly. Among these are potassium-40 and some isotopes of uranium, such as uranium-235 and uranium-238, which are of use for dating archaeologically related minerals and rocks (see Textboxes 15 and 16). 

In the broadest sense, genetic engineering refers to any artificial process that alters the genetic composition of an organism. Such alterations can be carried out indirectly through chemical methods, radiation, or selective breeding. The term usually refers to the process whereby genes or portions of chromosomes are chemically altered. 

Transfection. An artificial process of infecting cells with naked viral DNA. 

We thus realize that the duplication of functions of natural photosynthesis by means of artificial processes is conceivable. 

Absorption The assimilation of a solute, gas, or liquid into the interior of a solid material, an absorbent. Absorption may include the migration of solutes into internal pores or the migration or exchange of atoms within the crystalline structure of a mineral. Some researchers use the generic term sorption to refer to a natural or artificial process where both absorption and adsorption may be involved or if absorption and adsorption cannot be distinguished (compare with adsorption and sorption). 

The first indication of the modern concept of an element is to be found as early as Boyle (1627-1691), who was, however, far in advance of his time. Lavoisier (1743-1794) gives the purely empirical definition of an element, still valid in chemistry, as a substance which cannot be divided by any means or by any conversion. We must make an exception at present only for nuclear processes in which, both in natural radioactivity and in artificial processes brought about by neutrons, protons, etc., transmutation of the elements can take place. 

Anisodesmic reactions. Unfortunately most reactions of chemical interest belong to this category of processes that are not isodesmic and for which still larger correlation effects may be expected. As might be noticed, homodesmotic and isodesmic reactions are mostly artificial processes of little interest to chemists. One can, however, combine them in thermochemical cycles and to arrive in this way at real chemical problems. An example of the anisodesmic reaction... 

Its mode of action should be well described, preferring a natural process over an artificial process. 

In a sense, of course, although we have emphasised that our agent is natural, the Magistery may be regarded as an artificial process, without the aid of which the action of Nature either could not proceed at all, or else would not be accomplished so rapidly. But the moving principle and our Vulcan, which stirs up the motion, are undoubtedly natural, and it is only the excitation of the one by the other that could be described as anything else. 

A molecular dynamic simulation of the collision of a carbon atom and a fullerene molecule was performed recently to demonstrate a new method of producting a fullerene molecule with defects [46]. Such simulations can be considered both a model of an artificial process of atomic implantation and a model of collisions which can occur in the hot carbon vapors. 

Nitrogen mobilization ALL flows that convert inert nitrogen to reactive nitrogen. Includes natural processes such as nitrogen fixation in soybean, microbial fixation, and artificial processes such as the Haber—Bosch process Related agricultural sectors such as oilseed farming, etc. and fertilizer manufacturing sector... 

After identifying the materials forming the natural slope we are interested in, we might then identify the natural and artificial processes that might lead to its instability. We should then be able to hypothesize a plausible landslide type for the slope by comparison with movements of similar slopes nearby. 

The process of the artificial cellulose was visually analyzed by using transmission electron microscopy (24). Cellulose formation was detected as early as 30 s after the initial stage of the reaction in the aqueous acetonitrile. The electron diffraction pattern of the product showed the typical pattern of the crystal structure of thermodsmamically stable cellulose II with antiparallel orientation between each glucan chains. When the purified cellulase (39 kDa) was used, cellulose microfibrils with an electron diffraction pattern characteristic of metastable cellulose I with parallel orientation, an allomorph of natural cellulose, were first observed in an artificial process (25). Based on these results, a new concept of choroselectivity, selectivity concerning the relative ordering of the polymer chain direction, in polsrmerization chemistry has been proposed (26-28). 

Commercial and Artificial Processing. Commercially, silkworm cocoons are extracted in hot soapy water to remove the sticky sericin protein. The remaining fibroin or structural silk is reeled onto spools, yielding approximately 300-1200 m of usable thread per cocoon. These threads can be dyed or modified... 

This process causes some difficulties for the devout Aristotelian, by implying that the specific form of metal is gold, and that the lesser metals are merely faulty versions of this perfect substance. It also enabled alchemists to argue that, using artificial processes, they could therefore help nature along, but in shorter time [13] ... 

Nature created multienzymatic systems to accomplish extremely efficient one-pot tandem catalysis. As in an assembly line, tens of enzymes are well organised to transform simple materials to complex molecules with perfect control of selectivity hy a series of coupled reactions in the cell. It has long been chemists endeavor to extend such coordinated catalytic action to artificial processes to make synthetic chemistry more sustainable. Nowadays, owing to the resource-intensive nature of the current synthetic industry, the development of tandem one-pot reactions, avoiding the use of costly and time-consuming protection-deprotection processes as well as purification procedures of intermediates, has become especially important and valuable because society is confronted with bottle-neck problems such as energy and time shortage and environmental pollution. 

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