Some of the oxidation-reduction properties of the chorionic gonadotropic hormone

Gurin, Bachman, and Wilson (1-3) have recently made important contributions to our knowledge of the chemical nature of the gonadotropic hormone of pregnancy urine. They have given a method for the preparation of the hormone in a highly purified form and have described many of its outstanding chemical and physical properties. We have been especially interested in the reference of these authors to the unexplained, continuous, and apparently spontaneous inactivation of their highly purified material which takes place, particularly in aqueous solution, without, detectable loss or rupture of certain portions of the molecule (3). Earlier communications (4-6) have called attention to our observations relative to the oxidation and inactivation of a reducing factor of pregnancy urine which appears to be the chorionic gonadotropic hormone. Some of our more recent findings appear to shed light upon the observations of the above authors. The spontaneous oxidation of this reducing factor proceeds at a very slow rate but is more rapid in aqueous solution than in urine, where other stronger reducing agents tend to protect it. If activating agents are added and moderate heat is applied, the activity becomes of sufficient magnitude to bring about the reduction of dilute solutions of iodine or other oxidants. The object of this paper is to describe some of the rather unusual characteristics of this oxidation-reduction system

Estimated shuttle loading emissions

As space shuttle tanks are loaded with N2O4, pressurization gas is displaced and at the same time N2O4 entering the tank evaporates and mixes with the pressurization gas remaining in the tank. Further addition of N2O4 to the tank requires venting of this mixture of N2O4/NO2 vapor and pressurization gas, which must be scrubbed prior to atmospheric release. A computer analysis was performed to estimate concentrations, flow rates, and total quantities vented during the planned fast fill/slow fill cycles of 125 gallon and 640 gallon space shuttle tanks. With helium as the pressurization gas, total vent quantities were estimated to be 4.5 and 24 pounds N2O4, respectively, for the two tank sizes

Improved transmittance measurement with a magnesium oxide coated integrating sphere

Simple and convenient technique has been found for extending transmittance measurement capability of conventional magnesium oxide coated integrating sphere system at low (near ultraviolet) wavelengths. Technique can be used to determine effect of contaminants on window materials and can also be used for measurements on thermal control coatings and telescope mirrors

Modelling Garbage Collection Algorithms --- Extend abstract

We show how abstract requirements of garbage collection can be captured using temporal logic. The temporal logic specification can then be used as a basis for process algebra specifications which can involve varying amounts of parallelism. We present two simple CCS specifications as an example, followed by a more complex specification of the cyclic reference counting algorithm. The verification of such algorithms is then briefly discussed

An Introduction to 3D User Interface Design

3D user interface design is a critical component of any virtual environment (VE) application. In this paper, we present a broad overview of three-dimensional (3D) interaction and user interfaces. We discuss the effect of common VE hardware devices on user interaction, as well as interaction techniques for generic 3D tasks and the use of traditional two-dimensional interaction styles in 3D environments. We divide most user interaction tasks into three categories: navigation, selection/manipulation, and system control. Throughout the paper, our focus is on presenting not only the available techniques, but also practical guidelines for 3D interaction design and widely held myths. Finally, we briefly discuss two approaches to 3D interaction design, and some example applications with complex 3D interaction requirements. We also present an annotated online bibliography as a reference companion to this article