Fred N. Huffman

Analysis of volatile N-nitroso compounds in drinking water at the part per trillion level

ConclusionVolatile gc-amenable N-nitroso compounds have not been found to be present in drinking water, even at ultra trace levels. Since sensitive analytical procedures do not currently exist for detecting the non-volatile N-nitroso compounds, such as the N-nitrosotriazines it should be clearly understood that these results refer only to the gas-chromatograph amenable N-nitroso compounds. Nothing is to be inferred as to the presence or absence of the more thermally labile N-nitroso compounds.

Liquid Chromatograph Detector for Trace Analysis of Non-Volatile N-Nitroso Compounds

Abstract A Thermal Energy Analyzer has been interfaced to a high performance liquid chromatograph. The hplc-TEA system can be used for analysis of nanogram amounts of N-nitroso compounds.

Performance of a Tuned Ferrite Core Transcutaneous Transformer

The development of a practical power transmission system for a rechargeable artificial heart requires not only a means of efficiently coupling the required electromagnetic energy across the skin, but also a charge regulator, a primary cooling loop, and a suspension system for aligning the cores. This paper describes a tuned transcutaneous transformer which utilizes ferrite pot cores with Litz windings. Typically, the transformer operates over a frequency range from 12 to 20 kHz. Power levels of 150 W into a 16-? load have been demonstrated in vivo.

Radioisotope Powered Cardiac Pacemakers

Over 50, 000 implantable cardiac pacemakers are in use to rehabilitate patients with heart block. The chemical batteries powering these pacemakers usually fail within a few years. A variety of nuclear batteries, with the potential of providing long-lived (10 - 20 years) pacemaker power, are under development. This paper reviews the status of this development. Nuclear-powered pacemakers have reached the stage of clinical evaluation. Their cost, although initially high, is not prohibitive. The primary problem inhibiting widespread application is the maintenance of fuel capsule integrity under all creditable conditions.

Electron Microscopy and Thermal Analysis of Neointima Heated and Irradiated in Vivo for Two Years

The fine structure of a nonviable neointima formed in the lumen of an intravascular prosthesis during a continual two-year exposure to heat and radiation is described. Thermal and radiation measurements are analyzed and related to neointima ultrastructure. The observations indicate that classic, viable endothelium is not necessarily a prerequisite for either antithrombogenicity or heat transfer in circulatory assist devices. It is possible that similar nonviable neointima which provides blood compatibility, heat transfer to the circulating blood, and toleration of chronic low-level radiation can be utilized in projected totally implantable, nuclear-fueled, artificial circulatory support systems.