Microcontact printing (microCP) is an effective way to generate micrometer- or submicrometer-sized patterns on a variety of substrates. However, the fidelity of the final pattern depends critically on the coupled phenomena of stamp deformation, fluid transfer between surfaces, and the ability of the ink to self-assemble on the substrate. In particular, stamp deformation can produce undesirable effects that limit the practice and precision of microCP. Experimental observations and comparison with theoretical predictions are presented here for three of the most undesirable consequences of stamp deformation: (1) roof collapse of low aspect ratio recesses, (2) buckling of high aspect ratio plates, and (3) lateral sticking of high aspect ratio plates. Stamp behavior was observed visually with an inverted optical microscope while load-displacement data were collected during compression and retraction of stamps. Additionally, a "robotic stamper" was used to deliver ink patterns in precise locations on substrates. These monomolecular ink patterns were then observed in high contrast using the surface potential scanning mode of an atomic force microscope. Theoretical models based on continuum mechanics were used to accurately predict both physical deformation of the stamp and the resultant inking patterns. The close agreement between these models and the experimental data presented clearly demonstrates the essential considerations one must weigh when designing stamp geometry, material, and loading conditions for optimal pattern fidelity.

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Through the combination of robust mechanized experimental hardware and a flexible control system with an intuitive user interface, SSRL researchers have screened over 200 000 biological crystals for diffraction quality in an automated fashion. Three quarters of SSRL researchers are using these data-collection tools from remote locations.

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Synopsis Web-Ice is a scalable, extendable and portable software application for rapid on-line diffraction image analysis, autoindexing and strategy calculation. The Web-Ice architecture, software components and functionality both as a stand-alone application and as part of a beamline control system are described. AbstractNew software tools are introduced to facilitate diffraction experiments involving large numbers of crystals. While existing programs have long provided a framework for lattice indexing, Bragg spot integration, and symmetry determination, these initial data processing steps often require significant manual effort. This limits the timely availability of 1 data analysis needed for high-throughput procedures, including the selection of the best crystals from a large sample pool, and the calculation of optimal data collection parameters to assure complete spot coverage with minimal radiation damage. To make these protocols more efficient, we developed a network of software applications and application servers, collectively known as Web-Ice. When the package is installed at a crystallography beamline, a programming interface allows the beamline control software (e.g., Blu-Ice / DCSS) to trigger data analysis automatically. Results are organized based on a list of samples that the user provides, and are examined within a Web page, accessible both locally at the beamline or remotely. Optional programming interfaces permit the user to control data acquisition through the Web browser. The system as a whole is implemented to support multiple users and multiple processors, and can be expanded to provide additional scientific functionality. Web-Ice has a distributed architecture consisting of several stand-alone software components working together via a well defined interface. Other synchrotrons or institutions may integrate selected components or the whole of Web-Ice with their own data acquisition software. Updated information about current developments may be obtained at http://smb.slac.stanford.edu/research/developments/webice.

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A family of hybrid organic-inorganic network materials-the star gels and glasses-has been synthesized from highly functional poly(alkoxysilane) molecular precursors. The starting silanes comprise an atomic, linear or cyclic core with multiple flexible arms which terminate in network-forming trialkoxysilane groups. With typically 12 alkoxysilane groups per molecule, gelation rates in aqueous or formic acid media can be extremely high, but can be attenuated several orders of magnitude by choice of solvent system. Transparent, non-porous glasses generated from gels include large, flexible rings. Compressive stress-strain and nanoindentation tests indicate very high levels of toughness and show no evidence of any plastic deformation even under stresses which fracture fused silica. Inclusion of 5% of a star silane will substantially toughen purely inorganic glasses. The organic content of the networks can be increased by lengthening the arms; the inorganic content can be increased via co-gelation with simple tetraalkoxysilanes such as TEOS. Fluorine-bearing silanes have been used to surface-modify elastomers via ''fluoroinfusion'' in which sol-gel-generated networks interpenetrate those of the rubber. Gelation chemistry, kinetics, network architecture and relaxation behavior of the star glasses are discussed in the review.