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12.
Loschky Lester C.; Sethi Amit; Simons Daniel J.; Pydimarri Tejaswi N.; Ochs Daniel; Corbeille Jeremy L. 《Canadian Metallurgical Quarterly》2007,33(6):1431
People can recognize the meaning or gist of a scene from a single glance, and a few recent studies have begun to examine the sorts of information that contribute to scene gist recognition. The authors of the present study used visual masking coupled with image manipulations (randomizing phase while maintaining the Fourier amplitude spectrum; random image structure evolution [RISE]; J. Sadr & P. Sinha, 2004) to explore whether and when unlocalized Fourier amplitude information contributes to gist perception. In 4 experiments, the authors found that differences between scene categories in the Fourier amplitude spectrum are insufficient for gist recognition or gist masking. Whereas the global 1/f spatial frequency amplitude spectra of scenes plays a role in gist masking, local phase information is necessary for gist recognition and for the strongest gist masking. Moreover, the ability to recognize the gist of a target image was influenced by mask recognizability, suggesting that conceptual masking occurs even at the earliest stages of scene processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
Tracy L. Westeyn Gregory D. Abowd Thad E. Starner Jeremy M. Johnson Peter W. Presti Kimberly A. Weaver 《Personal and Ubiquitous Computing》2012,16(2):169-191
Previous research has established the connection between the way in which children interact with objects and the potential
early identification of children with autism. Those findings motivate our own work to develop "smart toys," objects embedded with wireless sensors that are safe and enjoyable for very small children, that allow detailed interaction
data to be easily recorded. These sensor-enabled toys provide opportunities for autism research by reducing the effort required
to collect and analyze a child’s interactions with objects. In the future, such toys may be a useful part of clinical and
in-home assessment tools. In this paper, we discuss the design of a collection of smart toys that can be used to automatically
characterize the way in which a child is playing. We use statistical models to provide objective, quantitative measures of
object play interactions. We also developed a tool to view rich forms of annotated play data for later analysis. We report
the results of recognition experiments on more than fifty play sessions conducted with adults and children as well as discuss
the opportunities for using this approach to support video annotation and other applications. 相似文献
14.
Bethany Kolbaba-Kartchner I. Can Kazan Jeremy H. Mills S. Banu Ozkan 《International journal of molecular sciences》2021,22(6)
The relationship between protein motions (i.e., dynamics) and enzymatic function has begun to be explored in β-lactamases as a way to advance our understanding of these proteins. In a recent study, we analyzed the dynamic profiles of TEM-1 (a ubiquitous class A β-lactamase) and several ancestrally reconstructed homologues. A chief finding of this work was that rigid residues that were allosterically coupled to the active site appeared to have profound effects on enzyme function, even when separated from the active site by many angstroms. In the present work, our aim was to further explore the implications of protein dynamics on β-lactamase function by altering the dynamic profile of TEM-1 using computational protein design methods. The Rosetta software suite was used to mutate amino acids surrounding either rigid residues that are highly coupled to the active site or to flexible residues with no apparent communication with the active site. Experimental characterization of ten designed proteins indicated that alteration of residues surrounding rigid, highly coupled residues, substantially affected both enzymatic activity and stability; in contrast, native-like activities and stabilities were maintained when flexible, uncoupled residues, were targeted. Our results provide additional insight into the structure-function relationship present in the TEM family of β-lactamases. Furthermore, the integration of computational protein design methods with analyses of protein dynamics represents a general approach that could be used to extend our understanding of the relationship between dynamics and function in other enzyme classes. 相似文献
15.
Nicholas Vishnosky Jasmine C. Gomez Spencer T. Kim Emma J. Doukmak Jeremy Grafstein Rachel C. Steinhardt 《大分子材料与工程》2021,306(9):2100222
Actuators made of soft matter are needed for a variety of fields ranging from biomedical devices to soft robotics to microelectromechanical systems. While there are a variety of excellent methods of soft actuation known, the field is still an area of intense research activity as new niches and needs emerge with new technology development. Here, a soft actuation system is described, based on a core-multi-shell particle, which moves via photothermal expansion. The system consists of a novel polystyrene-based thermally expandable microsphere, with a secondary shell of a silicate-silane graft copolymer, to which gold nanoparticles are covalently linked. The gold nanoparticles act as photothermal nano-transducers, converting light energy into the thermal energy necessary for microsphere expansion, which in turn results in material movement. Actuation is shown in isolated particles in thermal and photothermal regimes using metal ceramic heaters or 520 nm laser illumination, respectively. Macroscale actuation is demonstrated by making a composite material of particles suspended in the transparent elastomer polydimethylsiloxane. The sample demonstrates an inchworm-like movement by starting from an arched geometry. Overall, this work describes a new particle-based actuation method for soft materials, and demonstrates its utility in driving the movement of a composite elastomer. 相似文献
16.
Eric W. Neuman Benjamin J. Lai Jeremy L. Watts Gregory E. Hilmas William G. Fahrenholtz Laura Silvestroni 《International Journal of Applied Ceramic Technology》2021,18(6):2224-2236
Densification behavior, microstructure, and mechanical properties of zirconium diboride (ZrB2) ceramics modified with a complex Zr/Si/O-based additive were studied. ZrB2 ceramics with 5–20 vol.% additions of Zr/Si/O-based additive were densified to >95% relative density at temperatures as low as 1400°C by hot-pressing. Improved densification behavior of ZrB2 was observed with increasing additive content. The most effective additive amount for densification was 20 vol.%, hot-pressed at 1400°C (∼98% relative density). Microstructural analysis revealed up to 7 vol.% of residual second phases in the final ceramics. Improved densification behavior was attributed to ductility of the silicide phase, liquid phase formation at the hot-pressing temperatures, silicon wetting of ZrB2 particles, and reactions of surface oxides. Room temperature strength ranged from 390 to 750 MPa and elastic modulus ranged from 440 to 490 GPa. Vickers hardness ranged from 15 to 16 GPa, and indentation fracture toughness was between 4.0 and 4.3 MPa·m1/2. The most effective additive amount was 7.5 vol.%, which resulted in high relative density after hot-pressing at 1600°C and the best combination of mechanical properties. 相似文献
17.
Jeremy Gustin Brian Freeman James Stone Mohammad Mahinfalah Amin Salehi‐Khojin 《应用聚合物科学杂志》2005,96(6):2309-2315
Nanocomposites are more widely studied today because of higher stiffness, decreased permeability, thermal stability, and many other properties superior to those of regular polymers. However, manufacturers are concerned about implementing nanocomposites because of their lower impact properties with respect to the base polymer. This study focused on low‐velocity impact tests of a thermoplastic olefin by itself and with 5 wt % nanoclay. The impact tests were conducted at ?40, 23.9, and 65.6°C until the polymer and nanocomposite plates experienced complete striker penetration. The force–time and force–deflection responses obtained from the impact testing provided a means of comparing the impact performances of the two materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2309–2315, 2005 相似文献
18.
Jeremy P. Wu Rees D. Rawlings Aldo R. Boccaccini Ivo Dlouhy Zdenek Chlup 《Journal of the American Ceramic Society》2006,89(8):2426-2433
A novel glass–ceramic material was developed from the melt of a TiO2 -containing iron-making slag with additional waste glass. The high percentage (∼20 wt% TiO2 ) of this network-modifying oxide has promoted a crystallization of the parent glass, resulting in a fine-grained, homogeneous polycrystalline material with high mechanical properties ( E =120 GPa, flexural strength=∼180 MPa, and Vickers hardness=7 GPa) after a heat treatment at 1100°C for 2 h. The room temperature and elevated temperature fracture toughness were also studied. The main crystalline phases of the glass–ceramic material were of the pyroxene series until heat-treatment temperature reached 1000°C, at which titanium-rich perovskite and armalcolite crystals became the dominant phases. The end material is high-strength, aesthetically acceptable (metallic gray or opaque brown colored), and suitable for structural and architectural applications. 相似文献
19.
Shuttleworth Wendy A.; Hough Colleen D.; Bertrand Kevin P.; Evans Jeremy N.S. 《Protein engineering, design & selection : PEDS》1992,5(5):461-466
5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, the productof the Escherichia coli aroA gene, has been overproduced inE.coli BL21(DE3) under the control of the T7 gene 10 promoterand ribosome binding site, to a level of {small tilde}50% oftotal cell protein. EPSP synthase is the primary target of thepost-emergence herbicide, glyphosate, commonly known as RoundupTM.A simple two step purification is described, which results in99% pure homogeneous protein (as determined by PAGE). The integrityof the protein has been compared with previously characterizedprotein from .E.coli AB2829(pKD501) by determination of itskinetic parameters, N-terminal protein and DNA sequences, aminoacid analysis and 13C-NMR spectroscopy. This new overproducingstrain readily provides the gram quantities of highly pure proteinrequired for NMR studies of the active site and the developmentof novel time-resolved solid-state NMR techniques currentlyunderway in this laboratory. 相似文献
20.
The importance of axial misalignment at polyethylene pipe butt fusion joints has been assessed by undertaking elevated temperature lifetime tests. Both medium and high density polyethylene pipes were fusion joined to give aligned and controlled misaligned butt joints. These were tested under either a constant or fluctuating internal pressure loading using conditions that induced failure by slow, stable crck growth. It was observed that the lifetime of a butt joined system depends upon both the internal pressure or pressure range applied and the level of misalignment at the butt fusion joint. Increasing either the internal pressure (range) or the misalignment reduced system performance. These two variables of misalignment and internal pressure (range) may be incorporated into a single parameter, the amplified axial stress (or stress range) at the butt joint. This amplified or butt joint axial stress (or stress range) may be derived by considering the additional bending stresses introduced at the butt joint by virtue of misalignment combined with the axial stress loading. 相似文献