Artificial substance

C13-0117. The development of artificial substances compatible with human tissue is an important area of research. One example is a polymer of lactic acid ... 

Since ferrous iron usually colors minerals green, and ferric iron yellow or brown, it may seem rather remarkable that the presence of both together should give rise to a blue color, as in the case of vivianite. It may be pointed out, however, that this is by no means a unique instance of such an effect. Even apart from the artificial substances, Prussian and Turnbull s blues, which are complex cyanides containing both ferric and ferrous iron, there are several blue minerals in which the color seems explainable only on this basis. The most noteworthy of these are crocidolite and related amphiboles iolite and the blue tourmaline or indicolite. Other instances may perhaps be discovered, should this subject ever be investigated as it deserves to be . 

Introduction Many natural and artificial substances are toxic to humans (and animals). Liquids and solids can be ingested, or exposure can be through the skin, eyes, or other external passages to the body. Where these substances are gaseous or volatile, toxic effects can result from inhalation. As a result ofaccidents and tests, it has been discovered that some of these substances are more toxic than others. Quantification of the degree of hazard has become important in devising appropriate measures for containing these substances. 

Fabric is a flexible, artificial substance made up of a network of natural or artificial fibres. It is formed by interlacing loops of yarn or thread and matting the fibers together by heat and pressure. 

In addition to naturally occurring growth factors for the immune system, several artificial substances that may be able to stimulate immune system regeneration are also being developed and tested. 

Hatchett, Charles, On an artificial substance which possesses the principal... 

PCP is a completely artificial substance. That is, it is not derived from anything in nature it is made purely from industrial chemicals. In fact, police are often tipped off to the presence of an illegal PCP laboratory when neighbors complain of terrible chemical smells or when careless criminals create chemical fires and explosions. 

In modern art, analytical techniques are of increased importance in flavor design. Sense of flavor is in general conservative and the use of artificial substances in this field is far less encouraged compared with fragrances. Consequently, reproduction of natural aroma is favored, and therefore analysis of foodstuff is the dominating force in innovation. However, naturally, techniques used in flavor analysis are applicable to fragrance analysis as well. 

The most classical artificial substances used in perfumery are as follows (Figure 5). Hydroxycitronellal (99) was found to exhibit the odor of lily of the valley, the essential oil of which is not possible to prepare in the first place. Other classics include ct-amylcinnamaldehyde (100) and musk ketone (101), which were discovered to be good substitutes for jasmine and musk, respectively. Furthermore, perfume No. 5 (Chanel, launched 1921) contained 2-methylundecanal, 1 with so unique an aroma character that it established No. 5 as the pioneer of a new fragrance class — floral aldehydic. 

Chemistry is the art of separating mixt bodies into their constituent parts of combining different bodies or the parts of bodies into new mixts for the purposes of philosophy arts, that is, for the purposes of philosophy by explaining the composition of bodies, the nature of mixture the properties of bodies thereon depending, for the purposes of arts by producing several artificial substances more suitable to the intention of various arts than any natural productions are. 

There is evidence that natural rubber was used by early Americans to make rubber balls over 2000 years ago. However, it has only been since the early twentieth century that rubber has become crucial to maintaining our standard of living in our current technology-based society. Synthetic rubbers, or elastomers as any artificial substance with elastic properties is called, have been a subject of intense research since the late 1800s. These materials were critically needed in the first half of the twentieth century to replace natural rubber in the tires for the newly invented automobile, due to shortages of natural rubber caused by wars. 

Aluminum is a constituent of many minerals, including clay (ka-olinite), mica, feldspar, sillimanite, and the zeolites. Some of these minerals are discussed under the chemistry of silicon, in Chapter 31. Aluminum oxide (alumina), occurs in nature as the mineral corundum. Corundum is the hardest of aU naturally occurring substances except diamond it scratches all other minerals, but is itself scratched by diamond, and also by the artificial substances boron carbide, and silicon carbide, SiC. Corundum and impure corundum (emery) are used as abrasives. 

More than in the past, sensorial delights for millions of consumers will be based on the close interaction of multiple disciplines including flavourists, chemists, toxicologists, technologists and chefs. In this context nature-identical and artificial substances will continue to play a major role in modem flavourings. 

The demand for natural foods in the western world is linked in with the concept of unprocessed and free from any artificial ingredients . In actual fact, virtually all foods are processed nowadays, not the least of which is to maintain the freshness demanded by the customer and to provide sufficient vitamins from chemically manufactured sources. For example, it has been calculated that to provide sufficient vitamin C from a natural source such as a lemon for the population of the UK would require lemon groves covering a third of the area of the UK and a more conducive climate Paradoxically, the concept that all natural substances are harmless whereas all artificial substances are harmful is often misguided since laboratory-made substances used as additives are often chemically identical to the natural substance and have invariably been tested against a wide battery of screens before being introduced up to carefully controlled levels into food. 

Figure 12.5-27. Peptidase-catalyzed modification of an artificial substance P precursor protein according to Schellenberger et al.p43. ...

Chemophobia has rooted itself deeply in society, but its origins are mainly conceptual. In everyday life, it is common to speak about chemicals or dangerous substances without actually specifying what these words mean. The word chemical (my personal favorite) is often used with the clear imphcations that there are other substances of non-chemical nature. In this context, the intended meaning of the word chemical is probably a substance produced by the chemical industry, which does not occur in nature, and potentially poses some sort of a hazard. However, this book will point out that the hazards of substances are not connected to their origins at all, natural and artificial substances are not different from this point of view. For an expert, this usage of the word chemical makes no sense as all substances are chemicals. 

A common counterargument is that while humans slowly adapted to natural substances over millions of years, the same is not true for artificial substances, which pose a constant risk. Well, one cannot get used to poisonous substances no matter how long time is available. Were this statement wrong, there would be no yearly accidents because of eating the same old toxic mushrooms or fish, or snake and spider bites. 

The sharp public distinction between natural (produced by evolution or created by God—which for the purposes of this story, does not matter— and human made substances is only a delusion. This assumption was once a scientific theory, it was called the vis vitalis theory and was thoroughly discredited almost two centuries ago. The modern-day variation of this theory posits that hving things add some sort of extra good nutrients to materials, which cannot be produced in any artificial way. Table 1.3 presents a set of toxicity data (given as values) on natural and artificial substances. Even a cursory look on these data will reveal that natural toxins have the distinction of being among the most poisonous substances known. 

The amount of the substance and mode of eiqiosure is much more important than any assumed tolerance that might develop toward poisons. A careful look at Table 1.3 will reveal a number of natural and artificial substances listed such as paracetamol, aspirin, caffeine, sodium nitrite and nicotine, which are more or less toxic, but still used in everyday life. This might seem contradictory at first sight, but there is a marked dose-response relationship. A lot of toxic substances may also have positive effects and can be used if there is a large difference between beneficial and toxic doses. There is an old Latin saying sola dosis facit venenum—it is the dose that makes the poison. Even very toxic botulinum toxin has an everyday use in cosmetics, it removes wrinkles when applied cautiously on the forehead between the eyebrows. This Botox cure has an effect for more than half a year a lot of celebrities use it instead of plastic surgeries. 

Improving someone s sports results is by no means prohibited in general. Its most conventional method is called training (what a surprise ). In addition, there are a few natural or artificial substances, which may have positive effects without being banned. The use of vitamins, great quantities of special energy drinks or special protein concentrates as dietary supplements is allowed. 

Various kinds of metals, originating from either natural or artificial substances, can contaminate water. In order to evaluate the toxicity of these metals, bioassays are required using aquatic organisms. Some species of algae, crustacean, or fish have been used for the toxicity tests. 

As already described, we need to achieve all of the merits in a good balanced manner, so that we can continue to develop our civilization. From the viewpoint, the environmental friendliness will be an indispensable concept for all engineering disciplines. Particularly, the surface of a material is the interface of materials, components, and all other engineered and artificial substances with environments... 

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