Iowa Agriculturist 68.03

Life Insurance and You 4 Skiing ... a day\u27s adventure 7 ISU Grads Tell What It IS Like in the Agri-business World 8 Agriculture in Greece 12 Plant Hunting - Behind the Iron Curtain 14 Creativity is the Word 15 Air Pollution 16 Campus Showcase 18 Winter Cotillion 21 Coeds Challenge Tradition 24 ISU Beef Herd Sets Pace 25 Campus March of Agriculture 26 Classroom and Campus 28 Strictly Bull 29 Dates for Penny Pinchers 30https://lib.dr.iastate.edu/iowaagriculturist/1047/thumbnail.jp

Iowa Agriculturist 69.01

The Governor Speaks Out On Iowa\u27s Brain Drain 2 Veishea 6 Students\u27 Prof of the Year 7 The Club Wants Recognition 8 Meatless Meats - Diet of the Future? 10 The Graduated or I feel the Draft 12 All-Ag Banquet 14 Water Conservation - Vital to All 16 The Story of Barbed Wire 18 All-out Chemical Warfare 21 A Day at the Ledges 22 Animal Farm 24 What Should He Be Like? 26 Campus March of Agriculture 28 Classroom and Campus 30 Strictly Bull 31https://lib.dr.iastate.edu/iowaagriculturist/1045/thumbnail.jp

Iowa Agriculturist 69.01

The Governor Speaks Out On Iowa's "Brain Drain" 2 Veishea 6 Students' Prof of the Year 7 The Club Wants Recognition 8 Meatless Meats - Diet of the Future? 10 The Graduated or I feel the Draft 12 All-Ag Banquet 14 Water Conservation - Vital to All 16 The Story of Barbed Wire 18 All-out Chemical Warfare 21 A Day at the Ledges 22 Animal Farm 24 What Should He Be Like? 26 Campus March of Agriculture 28 Classroom and Campus 30 Strictly Bull 31</p

Iowa Agriculturist 68.03

Life Insurance and You 4 Skiing ... a day's adventure 7 ISU Grads Tell What It IS Like in the Agri-business World 8 Agriculture in Greece 12 Plant Hunting - Behind the Iron Curtain 14 Creativity is the Word 15 Air Pollution 16 Campus Showcase 18 Winter Cotillion 21 Coeds Challenge Tradition 24 ISU Beef Herd Sets Pace 25 Campus March of Agriculture 26 Classroom and Campus 28 Strictly Bull 29 Dates for Penny Pinchers 30</p

Extending a Spectrin Repeat Unit. I: Linear Force-Extension Response

Nonequilibrium molecular dynamics simulations were used to calculate the elastic properties of a spectrin repeat unit. A contiguous α-helical linker was constructed by employing periodic boundary conditions, allowing a novel scheme for evaluating the thermodynamic force as a function of extension. By measuring the force-extension response under small extensions, spectrin was observed to behave primarily as an elastic material with a spring constant of 1700 ± 100 pN/nm. The implications of this spring constant, in terms of the properties of the spectrin tetramer, are also discussed

Extending a Spectrin Repeat Unit. II: Rupture Behavior

A spectrin repeat unit was subject to extension using cyclic expansion nonequilibrium molecular dynamics. Periodic boundary conditions were used to examine the effects of the contiguous α-helical linker on the force response. The measured force-extension curve shows a linear increase in the force response when the spectrin repeat unit is extended by ∼0.4 nm. After that point, the force response peaks and subsequently declines. The peak in the force response marks the point where the spectrin repeat unit undergoes a change in its material properties from a strongly elastic material to a mostly viscous one, on the timescales of the simulations. The force peak is also correlated with rupture of the α-helical linker, and is likely the event responsible for the peaks in the sawtooth-pattern force-extension curves measured by atomic force microscopy experiments. Rupture of the linker involves simultaneously breaking approximately four hydrogen bonds that maintain the α-helical linker. After this initial rupture, the linker undergoes simple helix-to-coil transitions as the spectrin repeat unit continues to be extended. The implications of linker rupture in the interpretation of unfolding and atomic force microscopy experiments are also discussed