L-selectin mediated leukocyte tethering in shear flow is controlled by multiple contacts and cytoskeletal anchorage facilitating fast rebinding events

L-selectin mediated tethers result in leukocyte rolling only above a threshold in shear. Here we present biophysical modeling based on recently published data from flow chamber experiments (Dwir et al., J. Cell Biol. 163: 649-659, 2003) which supports the interpretation that L-selectin mediated tethers below the shear threshold correspond to single L-selectin carbohydrate bonds dissociating on the time scale of milliseconds, whereas L-selectin mediated tethers above the shear threshold are stabilized by multiple bonds and fast rebinding of broken bonds, resulting in tether lifetimes on the timescale of $10^{-1}$ seconds. Our calculations for cluster dissociation suggest that the single molecule rebinding rate is of the order of $10^4$ Hz. A similar estimate results if increased tether dissociation for tail-truncated L-selectin mutants above the shear threshold is modeled as diffusive escape of single receptors from the rebinding region due to increased mobility. Using computer simulations, we show that our model yields first order dissociation kinetics and exponential dependence of tether dissociation rates on shear stress. Our results suggest that multiple contacts, cytoskeletal anchorage of L-selectin and local rebinding of ligand play important roles in L-selectin tether stabilization and progression of tethers into persistent rolling on endothelial surfaces.Comment: 9 pages, Revtex, 4 Postscript figures include

Weather, disease, and wheat breeding effects on Kansas wheat varietal yields, 1985 to 2011.

Wheat (Triticum aestivum L.) yields in Kansas have increased due to wheat breeding and improved agronomic practices, but are subject to climate and disease challenges. The objective of this research is to quantify the impact of weather, disease, and genetic improvement on wheat yields of varieties grown in 11 locations in Kansas from 1985 to 2011. Wheat variety yield data from Kansas performance tests were matched with comprehensive location-specific disease and weather data, including seasonal precipitation, monthly air temperature, air temperature and solar radiation around anthesis, and vapor pressure deficit (VPD). The results show that wheat breeding programs increased yield by 34 kg ha⁻¹ yr⁻¹. From 1985 through 2011, wheat breeding increased average wheat yields by 917 kg ha⁻¹, or 27% of total yield. Weather was found to have a large impact on wheat yields. Simulations demonstrated that a 1°C increase in projected mean temperature was associated with a decrease in wheat yields of 715 kg ha⁻¹, or 21%. Weather, diseases, and genetics all had significant impacts on wheat yields in 11 locations in Kansas during 1985 to 2011

Auditing Symposium VI: Proceedings of the 1982 Touche Ross/University of Kansas Symposium on Auditing Problems

Evolution of Audit reporting / Douglas R. Carmichael, Alan J. Winters; Discussant\u27s response to audit detection of financial statement errors / William F. Messier; Multi-Attribute model for audit evaluation / Theodore J. Mock, Michael G. Samet; Discussant\u27s response to a multi-attribute model for audit evaluation / Joseph X. Loftus; Some thoughts on materiality / Kenneth W. Stringer; Discussant\u27s response to some thought on materiality / Joseph J. Schultz; SAS 34 procedures vs forecast reviews: The Gap in GAAS / Robert Kay; Discussant\u27s response to SAS 34 procedures vs forecast reviews: The gap in GAAS / William R. Kinney; Development in governmental auditing: Their impact on the academic and business communities / Richard E. Brown; Discussant\u27s response to the evolution of audit reporting / J. Alex Milburn; How not to communicate material and immaterial weaknesses in accounting controls / Wanda A. Wallace; Discussant\u27s response to how not to communicate material and immaterial weaknesses in accounting controls / Alan N. Certain; Human information processing research in auditing A review and synthesis / Robert H. Ashton; Discussant\u27s response to human information processing research in auditing: a review and synthesis / Gary L. Holstrum; Audit detection of financial statement errors: Implications for the practitioner / Robert E. Hylashttps://egrove.olemiss.edu/dl_proceedings/1005/thumbnail.jp

Auditing Symposium V: Proceedings of the 1980 Touche Ross/University of Kansas Symposium on Auditing Problems

Historical perspective of government auditing -- With special reference to the U.S general accounting office / Leo Herbert; Discussant\u27s response to an historical perspective of government auditing with special reference to the U.S General Accounting Office / Richard E. Brown; Critical requirements of a system of internal accounting control / Robert J. Sack; Discussant\u27s response to critical requirements of a system of internal accounting control / Jay M. Smith; Taxonomization of internal controls and errors for audit research / Miklos A. Vasarhelyi; Discussant\u27s response to taxonomization of internal controls and errors for audit research / John K. Wulff; Investigation of a measurement based approach to the evaluation of audit evidence / Theodore J. Mock, Arnold Wright; Discussant\u27s response to an investigation of a measurement based approach to the evaluation of audit evidence / Bart H. Ward; Authors\u27 reply to discussant\u27s response: An investigation of a measurement based approach to the evaluation of audit evidence / Theodore J. Mock, Arnold Wright; Look at the record on auditor detection of management fraud / Donald R. Ziegler; Discussant\u27s response to a look at the record on auditor detection of management fraud / Robert L. Grinaker; Auditing implications derived from a review of cases and articles relating to fraud / W. Steve Albrecht, Marshall B. Romney; Discussant\u27s response to auditing implications derived from a review of cases and articles related to fraud / Henry J. Murphy; Unique audit problems of small businesses that operate under managerial dominance / Dan M. Guy; Discussant\u27s response to unique audit problems of small businesses that operate under managerial dominance / Albert A. Armstrong; Accounting profession in the 1980\u27s -- Some SEC perspectives / George C. Mead;https://egrove.olemiss.edu/dl_proceedings/1004/thumbnail.jp