Reconstruction Using Witness Complexes

We present a novel reconstruction algorithm that, given an input point set sampled from an object S, builds a one-parameter family of complexes that approximate S at different scales. At a high level, our method is very similar in spirit to Chew’s surface meshing algorithm, with one notable difference though: the restricted Delaunay triangulation is replaced by the witness complex, which makes our algorithm applicable in any metric space. To prove its correctness on curves and surfaces, we highlight the relationship between the witness complex and the restricted Delaunay triangulation in 2d and in 3d. Specifically, we prove that both complexes are equal in 2d and closely related in 3d, under some mild sampling assumptions.     

Uptake of 3H-cAMP by retinal pigment epithelium isolated from bluegill sunfish (Lepomis macrochirus)

Background  

Metabotropic glutamate receptors (mGluRs) regulate neuronal excitability and synaptic strength. The group I mGluRs, mGluR1 and 5, are widespread in the brain and localize to post-synaptic sites. The Homer protein family regulates group I mGluR function and distribution. Constitutively expressed 'long' Homer proteins (Homer 1b, 1c, 2 and 3) induce dendritic localization of group I mGluRs and receptor clustering, either internally or on the plasma membrane. Short Homer proteins (Homer 1a, Ania-3) exhibit regulated expression and act as dominant negatives, producing effects on mGluR distribution and function that oppose those of the long Homer proteins.     

Nuclear magnetic resonance of polymer electrolyte membrane fuel cells

In this review, the contribution of NMR spectroscopy to the development of the proton exchange membrane fuel cell (PEMFC) is discussed, with particular emphasis on its use in the characterization of structure and transport in proton exchange membranes (PEMs). Owing to copious amount of information available, results of the past decade will be the main focal point. In addition, its use as a screening tool for the PEM materials will be discussed. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.201000010     

The effects of heating on mechanical loss in tantala/silica optical coatings

Second-generation interferometric gravitational-wave detectors will operate at temperatures noticeably above room temperature. Study was done to determine what effect elevated temperatures would have on the Q and coating thermal noise of the detector mirrors. Results show that increased temperature increases loss angle in a manner that is more significant at higher frequencies. Trends show that the increased temperature will have a negligible effect at the low (100 Hz) frequencies important to second-generation detectors.     

Preparation and properties of conductive silver/photosensitive polyimide nanocomposites

A new electrically conductive photoresist has been developed. It is based on the dispersion of silver nanoflakes in a negative‐tone photosensitive polyimide (PSPI) precursor. 2‐Mercaptopropionic acid was used as the surfactant to modify the silver nanoflake surface for the dispersion of silver nanoflakes in the polymer. The silver/PSPI nanocomposites showed electrical conductivity at a low silver content of 10 wt %. The electrical conductivity of the silver/PSPI nanocomposites ranged from 10 to 10⁴ S/cm, which was dependent on the silver weight fraction in the resist formulation. Patterns with a resolution of 30 μm were obtained from the silver/PSPI nanocomposites. The silver/PSPI nanocomposites had excellent thermal properties. Their glass transition temperatures were above 360 °C and thermal decomposition temperatures were over 420 °C. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1575–1583, 2009     

An oxepinone route to carbohydrate based oxepines

Oxepines are ring expanded analogs of glycals that can be used to prepare septanose carbohydrates. A route to carbohydrate based oxepines that utilizes oxepinones as a key intermediate has been developed. The oxepinone intermediates were prepared via an amine catalyzed cycloisomerization of furanose hemi-ketals. 1,2-Reduction of the oxepinones followed by acetylation provided the novel ring expanded enol ether products. Moderate diastereoselectivity was observed for the reduction based on the starting oxepinone. 1,4-Addition onto the oxepinones was also demonstrated. Overall, the syntheses reported here will allow for ready access to novel ring expanded carbohydrate analogs.