Human body, chemical composition

Microspheres made of various polymers biodegradable to nonharm-ful compounds that could be metabolized and/or removed from organisms found many applications in medicine as carriers of drugs or other bioactive compounds [1 ]. Besides chemical composition there are also other properties of microspheres that are of primary importance to their medical applications. In particular, average diameters and diameter distributions illustrated in Table 1 based on data published in [5] are the relationship between the diameters of microspheres and their localization in various cells and tissues of the human body. 

Chemical substances, which are injected into laboratory animals, may cause tumors locally at the injection site, e.g., in the muscle, irrespective of the mechanism for the tumor formation. It is now well established that smooth-surfaced foreign bodies, regardless of their chemical composition, will produce sarcomas when transplanted subcutaneously into rodents (Moore 1991). It is difficult to evaluate the relevance for humans of such site-related tumor formation this issue has been further addressed by lARC (1999b). 

Understanding the total nutritional needs of the human body requires a more detailed consideration of the chemical composition of different nutrients. As we have seen in Chapter 22, the body cannot synthesize many of the amino acids needed to build proteins. For this reason, the body requires proteins that contain the essential amino acids in sufficient quantities. Too little animal protein will lead to nutritional deficiencies because plant proteins do not contain an adequate supply of all the amino acids that active humans must receive from their diets. 

Hydroxyapatite (HAP), the molecular formula of which is Ca5(P04)3(0H) or Caio(P04)6(OH)2, is the major inorganic constituent in bone, teeth, etc. in the human body. HAP has essentially the same chemical composition and crystalline structure as those of human bone and so has good bio-compatibility. For a long time, it has been widely used as a sclerotin material in setting broken bone, filling teeth, etc. [215]. In addition, HAP can also be used as a food additive and moisture-sensitive element, etc. 

As indicated in chapter 3.6., the time required for the cremation process depends mainly on the structure and chemical composition of the human body, but to a significant extent also on the construction and operation of the cremation oven. 

Biochemistry is the study of the chemical composition and structure of the human body and other living organisms, of the chemical reactions that take place within these organisms, and of the drugs and other substances that interact with them. 

The potential application of mPC-CE coupled to a mass spectrometer (mPC-CE-MS) in the clinical diagnosis of disease states is substantial. In part, this is due to the fact that the technique can be utilized in the direct analysis of any physiologically derived body fluid. This is demonstrated by the direct mPC-CE-MS analysis of aqueous humor obtained from a patient undergoing eye-surgery. The chemical composition of human aqueous humor is still poorly understood, mainly due to the limited sample amounts that can be collected. It has been suggested that the chemical content of this fluid may play a role in drainage of the human eye. In particular, the protein content of aqueous humor may contain important factors in this process. Hence, any method that can readily determine the protein content of aqueous humor would be of great benefit. 

Hendry, E.B. The osmotic pressure and chemical composition of human body fluids. Clin. Chem. 1962, 8, 246-265. 

Chemistry is the study of matter—in its many forms—and the way these forms react with each other. It deals with the smallest of ions that are used in the human body to process energy, with the inner workings of the Earth s core, and even with the faraway study of the chemical composition of rocks on Mars. Chemistry is a pervasive science, or as an anonymous writer once wrote, What in the world isn t chemistry ... 

If you check any food composition table, you would see that potassium and sodium are found together in every food category. Both in foods and in the human body, they are often accompanied by chloride, which is the chemically active form of the element chlorine. All the natural foods I can think of have a lot more potassium than sodium, but they all have both—and chloride. Processed foods (potato chips, breakfast cereals, roasted nuts, soft drinks, etc.) are the only foods that have more sodium than potassium, and I believe you can guess why. The manufacturers often add salt to their products. Why Table salt (sodium chloride) acts as a preservative and a flavor enhancer. Products have a longer shelf life, and, besides, the salty taste is popular and helps sell many commercial food products. Salt is, however, somewhat addictive, and excessive intakes of it complicate body chemistry and increase the risk of high blood pressure in some individuals. 

The bowel, one of the largest and most metabolically active organs, contains bacteria that may change the chemical composition of the human body. In renal failure the altered bacterial flora cause the accumulation of aliphatic amines in the gut (09, S25). Bacteria transform part of the choline in the gut to trimethylamine, which is reabsorbed and then either oxidized or demethylated to dimethylamine in the liver (S24). Dimethylamine enters the circulation and is excreted in the bile and urine. The trimethylamine and dimethylamine in the exhaled air of uremic patients may contribute to the classic fishy breath, which can be improved by hemodialysis or by gut sterilization with nonabsorbable antibiotics (S23, S25). The overall role of these compounds as uremic toxins, however, remains to be defined. 

Space and astronomy is the oldest of all sciences. Long before humans understood the composition of rocks and minerals, knew how chemical reactions take place, or even discovered how their own bodies were constructed and operated, they knew of the existence of bodies beyond the Earth s atmosphere other planets, stars, and a variety of strange objects for which they had only simple explanations. The knowledge that early astronomers had of the skies was quite remarkable. They were able to predict the motion of stars, the arrival of seasons, the appearance of eclipses, and other astronomical phenomena with an accuracy that is quite astonishing to modern scientists. 

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