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Previous investigation implicated surface charge and surface energy as factors which affect blood clotting. The present paper attempts to explore the theoretical basis for these affects. Expressions are also derived relating change and interfacial tension to the binding constants of the protein. Finally, the possibility of phase transition of the adsorbed protein is discussed and techniques for detecting such changes from adsorption measurements are presented.

A detailed deterministic model for the kinetics of protein synthesis is developed on the assumption that the kinetics of the system depends linearly on the messenger RNA concentration. While the concentration of such components as adaptor RNA and ribosomes are regarded as constant, the messenger RNA input is taken to be time dependent and the analysis is given for both step and ramp inputs. It is shown that the theory predicts a nonlinear build-up in protein concentration followed by a linear phase in agreement with some experimental results. The slope of the linear portion corresponds to the rate of messenger RNA production.

A design theory is developed for a compact artificial kidney utilizing microcapsules containing urease, ion exchange resin, and adsorbents for uric acid and creatinine. It is shown that the critical factor is the permeability property of the microcapsule wall and that an artificial kidney 10 cm in length and 2 cm in diameter is feasible.

The condition for the inverse piezoelectric effect in polymers is discussed and a thermodynamic criteria is derived. The resulting expression is related to the electrical configuration of the polymer and several promising structures are proposed. A dynamical model of the piezoelectric effect is given, and expressions are derived for the compliance and electromechanical losses.

The properties of the three main classes of orthopedic alloys (316L steel, Co-Cr alloys and titanium) are discussed, while all show good general corrosion resistance, the 316L steel have a tendency toward crevice corrosion. Fatigue fracture due to poor design and fabrication defects is discussed. A summary of some problems associated with the evaluation of tissue response is presented. Finally, a review of several new trends toward achieving tissue adhesion is presented.

Etude du vieillissement d'anodes en TiO 2 relativement fortement dopees dans l'obscurite exposees a une solution a 0,1 N de NaOH pendant des durees superieures a 100 heures

Enzyme amplifier systems have been implicated in such diverse physiological phenomena as vision and blood coagulation. Such systems are considered from a general point of view and the concept of steady state gain of the enzyme amplifier is introduced. Expressions for the latter are obtained, and several of the main factors influencing gain are discussed. The effect of the duration of the activation on the characteristics of the response is discussed, and the influence of small changes in the rate constants on the steady state gain is considered.

The present report provides a detailed systems analysis of the kidney and the associated electrolyte regulatory mechanism, which will be referred to, for purposes of brevity, as the renal chemostat. The model explicitly incorporates the effect of water and salt intake, pulmonary CO2 tension, as well as the main features of renal physiology as it is presently understood. Thus the regulatory function of both aldosterone and antidiuretic hormone are included as well as the effect of such parameters as pH, salt concentration, plasma volume and osmotic factors. The present work thus provides a basis for the development of an electronic analog of the renal-electrolyte system.