The normal and pathological movement of water in tissues and its relation to the colligative properties of solutions and to inflammation.
A series of studies, each suggested by those that preceded, were first concerned with the movement of water in parenchymatous cells of liver, kidney, submaxillary glands, and other glandular organs. Evidenee was soon obtained showing that these cells were isotonic as determined by the osmotic pressure they maintained, not with physiological salt solution (0.15 M), as at that time popularly assumed, but with sodium chloride in approximately twice this concentration. Cells of the liver or of the kidney acted as osmometers and measured the osmotic pressure which they maintained. When various eleetrolytes were tested, it was found that their osmotic pressures varied with the valence of the basic ions of the salts that were used, being, for example; I for monovalent sodium salts, 2 for calcium salt, 3 for lanthanum salts. Solutions of the salts of eleetrolytes manifest properties so bound together that they are designated colligative. These properties include osmotic pressure, depression of the freezing point, vapor tension, and boiling point of solutions. It is well established that any one of them provides data from which the others can be dedueed by appropriate calculation.1 The changes which oceurred in liver or in kidney were found to be in aecord with tables which record changes in the freezing point of graded solutions of salts of electrolytes, on the one hand, or of boiling points on the other. Visible necrosis of the skin of laboratory animals was produeed by injeetion into the dermis, and the molar strength of solutions of various electrolytes needed to cause it was determined. This varied with the valence of the basic ions of the salts that were tested and followed a sequence which was the same as that of the isotonicity of liver or of kidney cortex immersed in corresponding solutions. The molar concentration of amino acids that produced necrosis followed the same order as osmotic pressure of liver in the same solutions. The relation of necrosis to the colligative properties of electrolytes suggested a study of the relation of inflammatory reactions to the moleeular constitution of agents that cause them. Injection of injurious substances into the large serous cavities of the body, peritoneal and pleural, offered a method by which exudation of fluid, leucocytes, and plasma protein could be measured with considerable accuracy. The numerical results thus obtained give an adequate measure of the inflammatory reactions. The relations cited emphasize the dependence of normal and pathological changes upon the colligative properties of electrolytes and of organic compounds which direet the movement of water and of the compounds it may contain. With these relations in mind, it has seemed desirable to review the sequence of studies which were undertaken to measure the movement of water in cells and interstitial tissue under normal and under pathological conditions.
THE RELATION OF INFLAMMATION TO THE MOLECULAR STRUCTURE OF CARBON COMPOUNDS SOLUBLE IN THE FLUIDS OF THE BODY
The peritoneal, like the pleural cavity, gives opportunity to measure with adequate accuracy the activity of inflammatory reactions defined by movement of fluid within the cavity, by migration of leucocytes into it, and by exudation of proteins from the plasma. The activity of inflammatory reactions caused by saccharides or by alcohols that were tested varied in accord with their molecular weight, the osmotic pressure maintained by solutions of corresponding concentration, their boiling point, or by other colligative properties. Blood serum or globulin in the concentration with which it occurs in blood serum injected into the peritoneal cavity caused changes which differed little from those caused by physiological salt solution. Protein with molecular weight as low as that of cytochrome C (12,000) or ovalbumin (45,000) when in dilute solution (1 per cent) were rapidly absorbed, whereas trypsin and chymotrypsin under the same conditions caused very active inflammatory reactions because they set free amino acids and perhaps polypeptides with amino acids in short chains. The activity of inflammatory reactions caused by carbon compounds soluble in body fluids varied in accord with their colligative properties.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.