George M. Whitesides

Bio: George M. Whitesides is an academic researcher from Harvard University. The author has contributed to research in topics: Microcontact printing & Self-assembled monolayer. The author has an hindex of 240, co-authored 1739 publications receiving 269833 citations. Previous affiliations of George M. Whitesides include University of California, Davis & University of Texas at Austin.

Topographical Micropatterning of Poly(dimethylsiloxane) Using Laminar Flows of Liquids in Capillaries

Abstract: M. Grell, D. Lupo, A. Yasuda, Synth. Met. 2000, 111±112, 173. [9] K. S. Whitehead, M. Grell, D. D. C. Bradley, M. Jandke, P. Strohriegl, Appl. Phys. Lett. 2000, 76, 2946. [10] V. N. Bliznyuk, S. A. Carter, J. C. Scott, G. Glärner, R. D. Miller, D. C. Miller, Macromolecules 1999, 32, 391. [11] M. Redecker, D. D. C. Bradley, M. Inbasekaran, W. W. Wu, E. P. Woo, Adv. Mater. 1999, 11, 241. [12] J. P. Chen, G. Klaerner, J.-I. Lee. D. Markiewicz, V. Y. Lee, R. D. Miller, J. C. Scott, Synth. Met. 1999, 107, 129. [13] G. Klaerner, M. H. Davey, W. D. Chen, J. C. Scott, R. D. Miller, Adv. Mater. 1998, 10, 993. [14] M. Kreyenschmidt, G. Klärner, T. Fuhrer, J. Ashenhurst, S. Karg, W. D. Chen, V. Y. Lee, J. C. Scott, R. D. Miller, Macromolecules 1998, 31, 1099. [15] Y. He, S. Gong, R. Hattori, J. Kanicki, Appl. Phys. Lett. 1999, 74, 2265. [16] D. Sainova, T. Miteva, H. G. Nothofer, U. Scherf, H. Fujikawa, I. Glowacki, J. Ulanski, D. Neher, Appl. Phys. Lett. 2000, 76, 1810. [17] S. Janietz, D. D. C. Bradley, M. Grell, C. Giebeler, M. Inbasekaran, E. P. Woo, Appl. Phys. Lett. 1998, 73, 2453. [18] K. Meerholz, H. Gregorius, K. Müllen, J. Heinze, Adv. Mater. 1994, 6, 671. [19] D. M. Pai, J. F. Yanus, M. Stolka, J. Chem. Phys. 1984, 88, 4414. [20] C. D. Müller, T. Braig, H. Nothofer, M. Arnoldi, M. Groû, U. Scherf, O. Nuyken, K. Meerholz, Chem. Phys. Chem. 2000, 1, 207. [21] M. Jandke, P. Strohriegl, J. Gmeiner, W. Brütting, M. Schwoerer, Adv. Mater. 1999, 11, 1518. [22] H. G. Nothofer, Ph.D. Thesis, University of Potsdam, Potsdam, Germany 2001. [23] T. Yamamoto, Prog. Polym. Sci. 1992, 17, 1153. [24] E. P. Woo, M. Inbasekaran, W. Shiang, G. R. Roof, Int. Patent Appl. WO97/05 184, 1997. [25] M. Inbasekaran, W. Wu, E. P. Woo, US Patent 5 777 070, 1998. [26] A. J. Bard, L. A. Faulkner, Electrochemical MethodsÐFundamentals and Applications, Wiley, New York 1984.

A microfluidic apparatus for the study of ice nucleation in supercooled water drops

Abstract: This paper describes a microfluidic instrument that produces drops of supercooled water suspended in a moving stream of liquid fluorocarbon, and measures the temperatures at which ice nucleates in the drops. A microfluidic chip containing a monodisperse drop generator and a straight channel with 38 embedded resistance thermometers was placed in contact with a seven-zone temperature-control plate and imaged under a microscope with a high-speed camera. This instrument can record the freezing temperatures of tens of thousands of drops within minutes, with an accuracy of 0.4 degrees C. The ice-nucleation temperatures in approximately 80-microm drops were reported for the freezing of 37 061 drops of pure water, and of 8898 drops of water seeded with silver iodide. Nucleation of ice in pure water was homogenous and occurred at temperatures between -36 and -37.8 degrees C, while water containing silver iodide froze between -10 and -19 degrees C. The instrument recorded the largest sets of individual freezing temperatures (37 061), had the fastest data acquisition rate (75 measurements/s), and the best optical (3 microm) and temporal (70 micros) resolutions among instruments designed to study nucleation of ice. The dendritic growth of ice in 150-microm drops of supercooled water at -35 degrees C was observed and imaged at a rate of 16 000 frames/s.

Mixing with bubbles: a practical technology for use with portable microfluidic devices.

Abstract: This paper demonstrates a methodology for micromixing that is sufficiently simple that it can be used in portable microfluidic devices. It illustrates the use of the micromixer by incorporating it into an elementary, portable microfluidic system that includes sample introduction, sample filtration, and valving. This system has the following characteristics: (i) it is powered with a single hand-operated source of vacuum, (ii) it allows samples to be loaded easily by depositing them into prefabricated wells, (iii) the samples are filtered in situ to prevent clogging of the microchannels, (iv) the structure of the channels ensure mixing of the laminar streams by interaction with bubbles of gas introduced into the channels, (v) the device is prepared in a single-step soft-lithographic process, and (vi) the device can be prepared to be resistant to the adsorption of proteins, and can be used with or without surface-active agents.

A General Method for Patterning Gradients of Biomolecules on Surfaces Using Microfluidic Networks

Abstract: This report outlines a general method for the fabrication of immobilized gradients of biomolecules on surfaces. This method utilizes a microfluidic network that generates a gradient of avidin in solution and immobilizes this protein on the surface of glass or poly(dimethylsiloxane) by physical adsorption. The immobilized gradient of avidin is then translated into gradients of biotinylated ligands (e.g., small molecules, oligomers of DNA, polysaccharides) using the specific interaction between biotin and avidin. This method can also generate immobilized gradients of certain proteins and artificial polymers by a direct transfer of gradients from solution onto the surface. The major advantage of this method is that almost any type of molecule can, in principle, be immobilized in a well-defined surface gradient of arbitrary shape with dimensions of a few micrometers to a few centimeters. It is possible to tailor the precise shapes of gradients on surfaces from gradients in solution, either kinetically or comp...

Surface-Initiated Ring-Opening Metathesis Polymerization on Si/SiO2

Abstract: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, Department of Chemistry and the Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Large-scale pattern growth of graphene films for stretchable transparent electrodes

Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites

Abstract: Multilayer films of organic compounds on solid surfaces have been studied for more than 60 years because they allow fabrication of multicomposite molecular assemblies of tailored architecture. However, both the Langmuir-Blodgett technique and chemisorption from solution can be used only with certain classes of molecules. An alternative approach—fabrication of multilayers by consecutive adsorption of polyanions and polycations—is far more general and has been extended to other materials such as proteins or colloids. Because polymers are typically flexible molecules, the resulting superlattice architectures are somewhat fuzzy structures, but the absence of crystallinity in these films is expected to be beneficial for many potential applications.