Patterned Protein Microarrays for Bacterial Detection

Abstract Patterned microarrays of antibodies were fabricated and tested for their ability to bind targeted bacteria. These arrays were used in a series of bacterial immunoassays to detect E. coli 0157:H7 and Renibacterium Salmoninarum (RS). Microarrays were fabricated using microcontact printing (µCP) and characterized using scanning probe microscopy (SPM). The high-resolution SPM imaging showed that targeted bacteria had a higher binding selectivity to complementary antibody patterns than to unfunctionalized regions of the substrate. Additional studies indicated a significant reduction in binding of bacteria when the microarrays were exposed to non-specific bacteria. These studies demonstrate how protein microarrays could be developed into useful platforms for sensing microorganisms.

Nanometrology Room Design: The Performance and Characterization of the Kevin G. Hall High-Accuracy Laboratory

New buildings focused on the practice of nanotechnology reflect a pressing need to develop advanced techniques to enable reliable work at the nanoscale. Often when planning a nanotechnology building, a decision must be made to include high-accuracy nanometrology rooms. The purpose of these rooms is to provide high-quality space that can be utilized on a daily basis to facilitate experiments requiring nanoscale precision, to develop new instrumentation, and to develop new techniques capable of probing the nanoscale. Typically, these rooms reduce vibration (including acoustic noise) and electromagnetic interference to very low levels while maintaining a high level of temperature stability. This study describes the characterization and performance of the Kevin G. Hall Nanometrology Laboratory located in the Birck Nanotechnology Center at Purdue University

FORCE CONSTANCY AND ITS ROLE ON HAPTIC PERCEPTION OF VIRTUAL SURFACES

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Force constancy and its effect on haptic perception of virtual surfaces

The force-constancy hypothesis states that the user of a force-feedback device maintains a constant penetration force when stroking virtual surfaces in order to perceive their topography. The hypothesis was developed to address a real-world data perceptualization problem where the perception of surface topography was distorted when the surface stiffness was nonuniform. Two experiments were conducted. In Experiment I, we recorded the penetration depths of the probe tip while the user stroked two surfaces with equal height but different stiffness values. We found that the data could be quantitatively modeled by the force-constancy hypothesis when the virtual surfaces were neither too soft nor too hard. In Experiment II, we demonstrated that given two adjacent surfaces, their perceived height difference depended on both the surface stiffness values as well as the relative heights of the surfaces. Specifically, we showed that the higher but softer surface could be perceived to be lower, at the same height, or higher than the other surface, depending on how much higher it was than the other surface. The results were consistent with the predictions of the force-constancy hypothesis. Our findings underscore the importance of understanding the interplay of haptic rendering parameters. Categories and Subject Descriptors: H.1.2 [Models and Principles]: User/Machine Systems—human information processing; H.5.1 [Information Interfaces and Presentation]: Multimedia Information Systems—artificial, augmented, and virtual realities