Institution
Northwestern University
Education•Evanston, Illinois, United States•
About: Northwestern University is a education organization based out in Evanston, Illinois, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 75430 authors who have published 188857 publications receiving 9463252 citations. The organization is also known as: Northwestern & NU.
Topics: Population, Transplantation, Cancer, Health care, Poison control
Papers published on a yearly basis
Papers
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TL;DR: In this paper, pH-induced self-assembly of a peptide-amphiphile was used to make a nanostructured fibrous scaffold reminiscent of extracellular matrix.
Abstract: We have used the pH-induced self-assembly of a peptide-amphiphile to make a nanostructured fibrous scaffold reminiscent of extracellular matrix. The design of this peptide-amphiphile allows the nanofibers to be reversibly cross-linked to enhance or decrease their structural integrity. After cross-linking, the fibers are able to direct mineralization of hydroxyapatite to form a composite material in which the crystallographic c axes of hydroxyapatite are aligned with the long axes of the fibers. This alignment is the same as that observed between collagen fibrils and hydroxyapatite crystals in bone.
3,125 citations
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13 Mar 2000TL;DR: In this article, the role of memory in response to survey questions is discussed. And the impact of the application of cognitive models to survey measurement is discussed, as well as the effect of these models on survey reporting of sensitive topics.
Abstract: 1. Introduction 2. Respondents' understanding of survey questions 3. The role of memory in survey responding 4. Answering questions about date and durations 5. Attitude questions 6. Factual judgments and numerical estimates 7. Attitude judgments and context effects 8. Mapping and formatting 9. Survey reporting of sensitive topics 10. Mode of data collection 11. Impact of the application of cognitive models to survey measurement.
3,114 citations
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01 May 1983TL;DR: In this article, a fracture theory for a heterogenous aggregate material which exhibits a gradual strain-softening due to microcracking and contains aggregate pieces that are not necessarily small compared to structural dimensions is developed.
Abstract: A fracture theory for a heterogenous aggregate material which exhibits a gradual strain-softening due to microcracking and contains aggregate pieces that are not necessarily small compared to structural dimensions is developed. Only Mode I is considered. The fracture is modeled as a blunt smeard crack band, which is justified by the random nature of the microstructure. Simple triaxial stress-strain relations which model the strain-softening and describe the effect of gradual microcracking in the crack band are derived. It is shown that it is easier to use compliance rather than stiffness matrices and that it suffices to adjust a single diagonal term of the complicance matrix. The limiting case of this matrix for complete (continuous) cracking is shown to be identical to the inverse of the well-known stiffness matrix for a perfectly cracked material. The material fracture properties are characterized by only three parameters—fracture energy, uniaxial strength limit and width of the crack band (fracture process zone), while the strain-softening modulus is a function of these parameters. A method of determining the fracture energy from measured complete stres-strain relations is also given. Triaxial stress effects on fracture can be taken into account. The theory is verified by comparisons with numerous experimental data from the literature. Satisfactory fits of maximum load data as well as resistance curves are achieved and values of the three material parameters involved, namely the fracture energy, the strength, and the width of crack band front, are determined from test data. The optimum value of the latter width is found to be about 3 aggregate sizes, which is also justified as the minimum acceptable for a homogeneous continuum modeling. The method of implementing the theory in a finite element code is also indicated, and rules for achieving objectivity of results with regard to the analyst's choice of element size are given. Finally, a simple formula is derived to predict from the tensile strength and aggregate size the fracture energy, as well as the strain-softening modulus. A statistical analysis of the errors reveals a drastic improvement compared to the linear fracture theory as well as the strength theory. The applicability of fracture mechanics to concrete is thus solidly established.
3,102 citations
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TL;DR: Meshless approximations based on moving least-squares, kernels, and partitions of unity are examined and it is shown that the three methods are in most cases identical except for the important fact that partitions ofunity enable p-adaptivity to be achieved.
3,082 citations
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TL;DR: The article presents a review of the book “Organizational Citizenship Behavior: The Good Soldier Syndrome,” by Dennis W. Organ.
Abstract: The article presents a review of the book “Organizational Citizenship Behavior: The Good Soldier Syndrome,” by Dennis W. Organ.
3,065 citations
Authors
Showing all 76189 results
Name | H-index | Papers | Citations |
---|---|---|---|
George M. Whitesides | 240 | 1739 | 269833 |
Ralph B. D'Agostino | 226 | 1287 | 229636 |
Daniel Levy | 212 | 933 | 194778 |
David Miller | 203 | 2573 | 204840 |
Ronald M. Evans | 199 | 708 | 166722 |
Michael Marmot | 193 | 1147 | 170338 |
Robert C. Nichol | 187 | 851 | 162994 |
Scott M. Grundy | 187 | 841 | 231821 |
Stuart H. Orkin | 186 | 715 | 112182 |
Michael A. Strauss | 185 | 1688 | 208506 |
Ralph Weissleder | 184 | 1160 | 142508 |
Patrick O. Brown | 183 | 755 | 200985 |
Aaron R. Folsom | 181 | 1118 | 134044 |
Valentin Fuster | 179 | 1462 | 185164 |
Ronald C. Petersen | 178 | 1091 | 153067 |