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
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TL;DR: The discrete dipole approximation is used to investigate the electromagnetic fields induced by optical excitation of localized surface plasmon resonances of silver nanoparticles, including monomers and dimers, with emphasis on what size, shape, and arrangement leads to the largest local electric field (E-field) enhancement near the particle surfaces.
Abstract: We use the discrete dipole approximation to investigate the electromagnetic fields induced by optical excitation of localized surface plasmon resonances of silver nanoparticles, including monomers and dimers, with emphasis on what size, shape, and arrangement leads to the largest local electric field (E-field) enhancement near the particle surfaces. The results are used to determine what conditions are most favorable for producing enhancements large enough to observe single molecule surface enhanced Raman spectroscopy. Most of the calculations refer to triangular prisms, which exhibit distinct dipole and quadrupole resonances that can easily be controlled by varying particle size. In addition, for the dimer calculations we study the influence of dimer separation and orientation, especially for dimers that are separated by a few nanometers. We find that the largest /E/2 values for dimers are about a factor of 10 larger than those for all the monomers examined. For all particles and particle orientations, the plasmon resonances which lead to the largest E-fields are those with the longest wavelength dipolar excitation. The spacing of the particles in the dimer plays a crucial role, and we find that the spacing needed to achieve a given /E/2 is proportional to nanoparticle size for particles below 100 nm in size. Particle shape and curvature are of lesser importance, with a head to tail configuration of two triangles giving enhanced fields comparable to head to head, or rounded head to tail. The largest /E/2 values we have calculated for spacings of 2 nm or more is approximately 10(5).
1,778 citations
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TL;DR: In this article, the tension between cooperation and competition affects the dynamics of learning alliances, and the competitive aspects of alliances are most severe when a firm's ratio of private to common benefits is high.
Abstract: We show how the tension between cooperation and competition affects the dynamics of learning alliances. 'Private benefits' and 'common benefits' differ in the incentives that they create for investment in learning. The competitive aspects of alliances are most severe when a firm's ratio of private to common benefits is high. We introduce a measure, 'relative scope' of a firm in an alliance, to show that the opportunity set of each firm outside an alliance crucially impacts its behavior within the alliance. Finally, we suggest why firms might deviate from the theoretically optimal behavior patterns. ? 1998 John Wiley & Sons, Ltd.
1,768 citations
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Donostia International Physics Center1, Rovira i Virgili University2, Victoria University of Wellington3, MacDiarmid Institute for Advanced Materials and Nanotechnology4, University of Cambridge5, University of California, Santa Barbara6, Queen's University Belfast7, Technical University of Denmark8, University of Victoria9, Chung-Ang University10, University of Jena11, Leibniz Institute of Photonic Technology12, Rutgers University13, University of Strathclyde14, University of Liverpool15, University of Iowa16, University of Minnesota17, Heidelberg University18, National Institute of Advanced Industrial Science and Technology19, Chalmers University of Technology20, Humboldt University of Berlin21, University of Michigan22, Jiangnan University23, Stanford University24, Xiamen University25, Ludwig Maximilian University of Munich26, Hokkaido University27, Seoul National University28, University of Illinois at Urbana–Champaign29, Kwansei Gakuin University30, University of Vigo31, Free University of Berlin32, Northwestern University33, University of Duisburg-Essen34, National Research Council35, Indian Institute of Science Education and Research, Thiruvananthapuram36, Duke University37, Northeastern University (China)38, Temple University39, Wuhan University40, Japan Advanced Institute of Science and Technology41, Jilin University42, Ikerbasque43
TL;DR: Prominent authors from all over the world joined efforts to summarize the current state-of-the-art in understanding and using SERS, as well as to propose what can be expected in the near future, in terms of research, applications, and technological development.
Abstract: The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.
1,768 citations
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Ohio State University1, Fred Hutchinson Cancer Research Center2, University of Cincinnati3, University of Iowa4, University of California, Davis5, University of Alabama at Birmingham6, University of Arizona7, University of Washington8, Rush University Medical Center9, Wake Forest University10, University of Nevada, Reno11, University of Texas at San Antonio12, Kaiser Permanente13, University of Pittsburgh14, University of California, Los Angeles15, Stony Brook University16, Baylor College of Medicine17, University of North Carolina at Chapel Hill18, Wayne State University19, Howard University20, George Washington University21, University of California, Irvine22, University of Tennessee Health Science Center23, Medical College of Wisconsin24, University of California, San Diego25, Rutgers University26, University of Florida27, National Institutes of Health28, Harvard University29, University of Minnesota30, University of Massachusetts Boston31, University of Miami32, Emory University33, University of Wisconsin-Madison34, Stanford University35, Northwestern University36, University at Buffalo37, Brown University38, Yeshiva University39
TL;DR: Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones.
Abstract: Background The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal. Methods We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers. Results Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with...
1,765 citations
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TL;DR: A hybrid biologically inspired adhesive consisting of an array of nanofabricated polymer pillars coated with a thin layer of a synthetic polymer that mimics the wet adhesive proteins found in mussel holdfasts is reported, useful for reversible attachment to a variety of surfaces in any environment.
Abstract: The adhesive strategy of the gecko relies on foot pads composed of specialized keratinous foot-hairs called setae, which are subdivided into terminal spatulae of approximately 200 nm (ref. 1). Contact between the gecko foot and an opposing surface generates adhesive forces that are sufficient to allow the gecko to cling onto vertical and even inverted surfaces. Although strong, the adhesion is temporary, permitting rapid detachment and reattachment of the gecko foot during locomotion. Researchers have attempted to capture these properties of gecko adhesive in synthetic mimics with nanoscale surface features reminiscent of setae; however, maintenance of adhesive performance over many cycles has been elusive, and gecko adhesion is greatly diminished upon full immersion in water. Here we report a hybrid biologically inspired adhesive consisting of an array of nanofabricated polymer pillars coated with a thin layer of a synthetic polymer that mimics the wet adhesive proteins found in mussel holdfasts. Wet adhesion of the nanostructured polymer pillar arrays increased nearly 15-fold when coated with mussel-mimetic polymer. The system maintains its adhesive performance for over a thousand contact cycles in both dry and wet environments. This hybrid adhesive, which combines the salient design elements of both gecko and mussel adhesives, should be useful for reversible attachment to a variety of surfaces in any environment.
1,762 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 |