Localization of a Breathing Crack Using Super-Harmonic Signals due to System Nonlinearity

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76712/1/AIAA-38947-457.pd

The focused ion beam as an integrated circuit restructuring tool

One of the capabilities of focused ion beam systems is ion milling. The purpose of this work is to explore this capability as a tool for integrated circuit restructuring. Methods for cutting and joining conductors are needed. Two methods for joining conductors are demonstrated. The first consists of spinning nitrocellulose (a self‐developing resist) on the circuit, ion exposing an area, say, 7×7 μm, then milling a smaller via with sloping sidewalls through the first metal layer down to the second, e‐beam evaporating metal, and then dissolving the nitrocellulose to achieve liftoff. The resistance of these links between two metal levels varied from 1 to 7 Ω. The second, simpler method consists of milling a via with vertical sidewalls down to the lower metal layer, then reducing the milling scan to a smaller area in the center of this via, thereby redepositing the metal from the lower layer on the vertical sidewall. The short circuit thus achieved varied from 0.4 to 1.5 Ω for vias of dimensions 3×3 μm to 1×1 μm, respectively. The time to mill a 1×1 μm via with a 68 keV Ga+ beam, of 220 Pa current is 60 s. In a system optimized for this application, this milling time is expected to be reduced by a factor of at least 100. In addition, cuts have been made in 1‐μm‐thick Al films covered by 0.65 μm of SiO2. These cuts have resistances in excess of 20 MΩ. This method of circuit restructuring can work at dimensions a factor of 10 smaller than laser zapping and requires no special sites to be fabricated

E-cadherin and cell adhesion: a role in architecture and function in the pancreatic islet

Background/Aims: The efficient secretion of insulin from beta-cells requires extensive intra-islet communication. The cell surface adhesion protein epithelial (E)-cadherin (ECAD) establishes and maintains epithelial tissues such as the islets of Langerhans. In this study, the role of ECAD in regulating insulin secretion from pseudoislets was investigated. Methods: The effect of an immuno-neutralising ECAD on gross morphology, cytosolic calcium signalling, direct cell-to-cell communication and insulin secretion was assessed by fura-2 microfluorimetry, Lucifer Yellow dye injection and insulin ELISA in an insulin-secreting model system. Results: Antibody blockade of ECAD reduces glucose-evoked changes in [Ca2+](i) and insulin secretion. Neutralisation of ECAD causes a breakdown in the glucose-stimulated synchronicity of calcium oscillations between discrete regions within the pseudoislet, and the transfer of dye from an individual cell within a cell cluster is attenuated in the absence of ECAD ligation, demonstrating that gap junction communication is disrupted. The functional consequence of neutralising ECAD is a significant reduction in insulin secretion. Conclusion: Cell adhesion via ECAD has distinct roles in the regulation of intercellular communication between beta-cells within islets, with potential repercussions for insulin secretion. Copyright (C) 2007 S. Karger AG, Basel

Channelling figurativity through narrative : the paranarrative in fiction and non-fiction

Contrary to wide-spread assumptions, metaphor in narrative is not a pre-established, extra-textual form appearing in different instances of discourse, but rather an event resulting from a strategic distribution of information in the narrative process. Hence, the appeal to conceptual cultural knowledge is to be considered as a consequence, and not as a prerequisite of metaphor interpretation. By means of the concept of the paranarrative, we highlight the rhetorical interconnectedness of metaphor with other figures of speech (such as metonymy) and we explore the narrative integration of diacritic forms of indirectness. In order to illustrate the terminology that can address these focal concerns, the paper discusses the relation between tropes and narrative, via selected examples from narrative texts (both fictional and non-fictional) written by Juli Zeh, Herta Müller, Jürgen Nieraad, and Siddhartha Mukherjee. As their common denominator, these examples channel through narrative figurative domains considered to be known intuitively to wit: personifications; iconic pars pro toto references to concentration camps; and metaphors for cancer in disease biographies

Processing of the papain precursor. Purification of the zymogen and characterization of its mechanism of processing.

The precursor of the cysteine protease papain has been expressed and secreted as propapain from insect cells infected with a recombinant baculovirus expressing a synthetic gene coding for prepropapain. This 39-kDa secreted propapain zymogen molecule is glycosylated and can be processed in vitro into an enzymatically active authentic papain molecule of 24.5 kDa (Vernet, T., Tessier, D.C., Richardson, C., Laliberte, F., Khouri, H. E., Bell, A. W., Storer, A. C., and Thomas, D. Y. (1990) J. Biol. Chem. 265, 16661-16666). Recombinant propapain was stabilized with Hg2+ and purified to homogeneity using affinity chromatography, gel filtration, and ion-exchange chromatographic procedures. The maximum rate of processing in vitro was achieved at approximately pH 4.0, at a temperature of 65 degrees C and under reducing conditions. Precursor processing is inhibited by a variety of reversible and irreversible cysteine protease inhibitors but not by specific inhibitors of serine, metallo or acid proteases. Replacement by site-directed mutagenesis of the active site cysteine with a serine at position 25 also prevents processing. The inhibitor 125I-N-(2S,3S)-3-trans-hydroxycarbonyloxiran-2-carbonyl-L-tyrosine benzyl ester covalently labeled the wild type papain precursor, but not the C25S mutant, indicating that the active site is accessible to the inhibitor and is in a native conformation within the precursor. Based on biochemical and kinetic analyses of the activation and processing of propapain we have shown that the papain precursor is capable of autoproteolytic cleavage (intramolecular). Once free papain is released processing can then occur in trans (intermolecular)

Sage‐Grouse Breeding and Late Brood‐Rearing Habitat Guidelines in Utah

Delineation, protection, and restoration of habitats provide the basis for endangered and threatened species recovery plans. Species recovery plans typically contain guidelines that provide managers with a scientific basis to designate and manage critical habitats. As such, habitat guidelines are best developed using data that capture the full diversity of ecological and environmental conditions that provide habitat across the species’ range. However, when baseline information, which fails to capture habitat diversity, is used to develop guidelines, inconsistencies and problems arise when applying those guidelines to habitats within an ecologically diverse landscape. Greater sage‐grouse (Centrocercus urophasianus; sage‐ grouse) populations in Utah, USA, reflect this scenario—published range‐wide habitat guidelines developed through a literature synthesis did not include data from the full range of the species. Although all sage‐ grouse are considered sagebrush obligates (Artemisia spp.), the species occupies a diversity of sagebrush communities from shrub‐dominated semideserts in the southwest to more perennial grass‐dominated sagebrush‐steppe in the northeast portions of their distribution. Concomitantly, local ecological site and environmental conditions may limit the ability of managers to achieve broader range‐wide habitat guidelines. We combined microsite habitat vegetation parameters from radiomarked sage‐grouse nest and brood locations with state‐wide spatially continuous vegetation, climatic, and elevation data in a cluster analysis to develop empirically based sage‐grouse habitat guidelines that encompass the range of ecological and environmental variation across Utah. Using this novel approach, we identified 3 distinct clusters of sage‐grouse breeding (i.e., nesting and early brood‐rearing) and late brood‐rearing habitats in Utah. For each cluster, we identified specific vegetation recommendations that managers can use to assess sage‐grouse breeding and late brood‐rearing habitat. Our results provide relevant guidelines to Utah’s sage‐grouse populations and are feasible given the unique ecological variation found therein. This approach may have application to other species that occupy diverse habitats and physiographic regions

Atomic-scale representation and statistical learning of tensorial properties

This chapter discusses the importance of incorporating three-dimensional symmetries in the context of statistical learning models geared towards the interpolation of the tensorial properties of atomic-scale structures. We focus on Gaussian process regression, and in particular on the construction of structural representations, and the associated kernel functions, that are endowed with the geometric covariance properties compatible with those of the learning targets. We summarize the general formulation of such a symmetry-adapted Gaussian process regression model, and how it can be implemented based on a scheme that generalizes the popular smooth overlap of atomic positions representation. We give examples of the performance of this framework when learning the polarizability and the ground-state electron density of a molecule