Sumner N. Levine

Enzyme amplifier kinetics

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.

A model for renal-electrolyte regulation

Abstract 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.

Relationships between municipal bond rates, underwriter margins and market yields

Abstract Expressions are given relating municipal bond coupon rates to underwrite profit margins and the market yield. These expressions are applied to the examination of net interest rates, net present value and the cost of capital of serial bond issues. The conditions which must be satisfied so that a decrease in net interest rate corresponds to an increase in net present value (hence a decrease in the cost of capital to the issuer) are presented.