American Lives: A Reader [Preface & Introduction]

Memoirs are as varied as human emotion and experience, and those published in the distinguished American Lives Series run the gamut. Excerpted from this series (called “splendid” by Newsweek) and collected here for the first time, these dispatches from American lives take us from China during the Cultural Revolution to the streets of New York in the sixties to a cabin in the backwoods of Idaho. In prose as diverse as the stories they tell, writers such as Floyd Skloot, Ted Kooser, Peggy Shumaker, and Lee Martin, among many others, open windows to their own ordinary and extraordinary experiences. John Skoyles tells how, for his Uncle Fred, a particular “Hard Luck Suit” imparted misfortune. Brenda Serotte describes a Turkish grandmother who made her living reading palms, interpreting cups, and prescribing poultices for the community. In “Son of Mr. Green Jeans,” Dinty W. Moore views fatherhood through the lens of pop culture. Janet Sternburg’s Phantom Limb muses on the dilemmas of a child caring for a parent. Whether evoking moments of death or disease, in family or marriage, history, politics, religion, or culture, these glimpses into singular American lives come together in a richly textured, colorful patchwork quilt of American life.

MECHANICAL TESTING DEVICE FOR VISCOELASTIC BIOMATERIALS

Nearly all biologic tissues exhibit viscoelastic behavior. This behavior is characterized by hysteresis in the response of the material to load or strain. This information can be utilized in extrapolation of life expectancy of vascular implant materials including native tissues and synthetic materials. This behavior is exhibited in many engineering materials as well such as the polymers PTFE, polyamide, polyethylene, etc. While procedures have been developed for evaluating the engineering polymers the techniques for biologic tissues are not as mature. There are multiple reasons for this. A major one is a cultural divide between the medical and engineering communities. Biomedical engineers are beginning to fill that void. A digitally controlled drivetrain designed to evaluate both elastic and viscoelastic characteristics of biologic tissues has been developed. The initial impetus for the development of this device was to evaluate the potential for human umbilical tissue to serve as a vascular graft material. The consequence is that the load frame is configured for membrane type specimens with rectangular dimensions of no more than 25mm per side. The designed load capacity of the drivetrain is to impose an axial load of 40N on the specimen. This drivetrain is capable of assessing the viscoelastic response of the specimens by four different test modes: stress relaxation, creep, harmonic induced oscillations, and controlled strain rate tests. The fluorocarbon PTFE has mechanical properties commensurate with vascular tissue. In fact, it has been used for vascular grafts in patients who have been victims of various traumas. Hardware and software validation of the device was accomplished by testing PTFE and comparing the results to properties that have been published by both researchers and manufacturers.