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SYNOPSISHyaluronic acid is a naturally occurring mucopolysaccharide. It is an important component of the intercellular matrix. It controls the permeability of tissues by means of the highly entangled network which can be formed because of its high molecular weight. To be able to use hyaluronic acid for several biomedical applications it is necessary to have an understanding of its swelling properties. Equilibrium swelling properties of hyaluronic acid gels were investigated by varying the temperature, pH, ionic strength, and composition of the surrounding solution. Swelling was found to depend on pH and ionic strength and to be reversible. The gel was highly swollen at high pH, but it shrank continuously as the pH was lowered to 10% of its maximum volume. The gel was comparatively insensitive to temperature. Drying affected the swelling capacity of the gel significantly. Gel swelling was also affected by a high concentration of acetone or propyl alcohol in the aqueous swelling solutions.

The preservative benefits of the enzymic glucose oxidase/catalase sys-I tern were measured in refrigerated, fresh, whole winter flounder (Pseudopleuronecres americanus Waldbaum) and winter flounder fillets. The enzyme system was applied as a dip, as an ice and immobilized in algin blankets. Advantages were an extended period of sensory acceptance and delayed onset of. putrefactive odors, 21 days vs 15 days for controls. The pattern of endogenous hypoxanthine accumulation and decline was unaffected, but parameters thought to measure proteolytic activity were modified: creatinine turnover was slowed and ammonia generation was retarded.

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Instantaneous mass transfer coefficients were obtained for the absorption of carbon dioxide bubbles rising in an aqueous solution of sodium carboxymethylcellulose. The rheological character of the solutions was well described by the Ellis model. Mass transfer coefficients were high initially but trailed off rapidly with bubble age. Exceptions were found at specific diameters where the bubble shape went through a transition. At about 0.2 cm. a transition from ellipsoidal to a sphere shape occurred, which has also been observed in Newtonian fluids. At a larger diameter, however, the non‐Newtonian fluid showed a shape change from a spherical “cap” to a “top” shape and finally to an ellipsoid. A sudden increase of mass transfer coefficient accompanied each shape transition. Drag coefficient data were correlated successfully with a new Reynolds number. The Newtonian and power law portion of the Ellis model each contributed a component to the Reynolds number, which, when added together, correlated drag data for the bubbles as well as for glass spheres. Attempts to account for transition shape changes and bubble tailing in the non‐Newtonian fluid and their effects on bubble mass transfer are included.