The relationship between polymer elastic properties and the ability to impart improved wrinkle recovery to cotton fabric

The wrinkle recovery of polymer-coated cotton printcloth was generally found to correlate qualitatively with the elastic behavior of the polymer film. Of the several tensile parameters that can describe elasticity, immediate strain and work recoveries and stress decay were found to be the most sensitive indicators of the polymers' performance on the fabric. Delayed recovery, ultimate elongation, and permanent set were found to be important but were less sensitive parameters; while tensile strength and initial modulus appeared to be unrelated. A model is described whereby the polymer provides additional recovery forces when properly coupled to the fabric. High values of stress decay and permanent set diminish the effectiveness of these forces, while high values of immediate, work, and delayed recovery indicate that large portions of the distorting forces are available for recovery.     

BBN TransTalk: Robust multilingual two-way speech-to-speech translation for mobile platforms

In this paper we present a speech-to-speech (S2S) translation system called the BBN TransTalk that enables two-way communication between speakers of English and speakers who do not understand or speak English. The BBN TransTalk has been configured for several languages including Iraqi Arabic, Pashto, Dari, Farsi, Malay, Indonesian, and Levantine Arabic. We describe the key components of our system: automatic speech recognition (ASR), machine translation (MT), text-to-speech (TTS), dialog manager, and the user interface (UI). In addition, we present novel techniques for overcoming specific challenges in developing high-performing S2S systems. For ASR, we present techniques for dealing with lack of pronunciation and linguistic resources and effective modeling of ambiguity in pronunciations of words in these languages. For MT, we describe techniques for dealing with data sparsity as well as modeling context. We also present and compare different user confirmation techniques for detecting errors that can cause the dialog to drift or stall.     

The impact of ripple on the design of advanced fuel tokamaks

Enhanced ion transport due to toroidal field ripple is a concern in the design of tokamak power reactors. This concern is quantified for advanced fuel cycle applications where the simultaneous requirement of highn and highT makes the constraint on deviation from axisymmetry especially severe.     

Compliant phase reduces polymerization shrinkage in dental composite resin

Commercially available dental composite resins undergo polymerization shrinkage during curing, setting up internal stress that can result in debonding at the tooth‐composite interface, tooth fracture and composite failure. Debonding can also lead to marginal leakage and recurrent decay. The presence of a compliant phase, in this case polybutadiene in aggregate form with fumed silica, is shown to reduce polymerization shrinkage in the bis‐GMA/TEGDMA resin system. The addition of a small amount of the plasticizer triphenylethylene promoted additional reduction in cure shrinkage by reducing the glass transition temperature, T_g. A trend toward reduced cure shrinkage was noted as the polybutadiene : silica ratio decreased within each molecular weight of polybutadiene tested. The optimal formulation tested was determined to be 0.25 wt. % triphenylethylene in bis‐GMA with aggregates formed from polybutadiene of molecular weight 2–3 million, in a polybutadiene : silica ratio of 0.005. Shrinkage reduction in this system was ～ 42% without loss of Knoop hardness. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2306–2310, 2005     

A possible role for singlet oxygen in the initiation of fatty acid autoxidation

A mechanism for the initiation of autoxidation in fatty acids is proposed which involves singlet state oxygen, formed through a photosensitization reaction, as the reactive intermediate. Both singlet oxygen generated in a radio-frequency gasdischarge, and photosensitization by natural pigments, were shown to catalyze the oxidation of methyl linoleate. The involvement of singlet oxygen was shown by the identification of nonconjugated hydroperoxides as products common to both photooxidation and singlet O₂ oxidation. Nonconjugated hydroperoxides could not be detected among the free radical autoxidation products. Further proof for the above mechanism was gained by showing that compounds known to react strongly with singlet oxygen, inhibited the photooxidation. With the exception of chlorophyll, all sensitizers could be completely inhibited. Although singlet oxygen formation can account for approximately 80% of the observed chlorophyll photooxidation, at least one other mechanism must be involved. It is postulated that proton abstraction by the photoactivated carbonyl group of chorophyll could account for the remaining 20% of the observed photooxidation. The conclusion is drawn that oxygen, excited to its singlet state by a photosensitization process, plays the important role of forming the original hydroperoxides whose presence is necessary before the normal free radical autoxidation process can begin.     

SCAR, a WASP-related protein, isolated as a suppressor of receptor defects in late Dictyostelium development

G protein-coupled receptors trigger the reorganization of the actin cytoskeleton in many cell types, but the steps in this signal transduction cascade are poorly understood. During Dictyostelium development, extracellular cAMP functions as a chemoattractant and morphogenetic signal that is transduced via a family of G protein-coupled receptors, the cARs. In a strain where the cAR2 receptor gene is disrupted by homologous recombination, the developmental program arrests before tip formation. In a genetic screen for suppressors of this phenotype, a gene encoding a protein related to the Wiskott-Aldrich Syndrome protein was discovered. Loss of this protein, which we call SCAR (suppressor of cAR), restores tip formation and most later development to cAR2(-) strains, and causes a multiple-tip phenotype in a cAR2(+) strain as well as leading to the production of extremely small cells in suspension culture. SCAR-cells have reduced levels of F-actin staining during vegetative growth, and abnormal cell morphology and actin distribution during chemotaxis. Uncharacterized homologues of SCAR have also been identified in humans, mouse, Caenorhabditis elegans, and Drosophila. These data suggest that SCAR may be a conserved negative regulator of G protein-coupled signaling, and that it plays an important role in regulating the actin cytoskeleton.     

In vitro gentamicin sustained and controlled release from chitosan cross-linked films

A novel wound dressing film was investigated for controlled and sustained delivery of gentamicin, while covering and protecting the wound. Chitosan was cross-linked with Hexamethylene 1,6-bis (aminocarboxysulfonate) to prepare the wound dressing films. Cross-linking reaction was required to control the water retention and release of encapsulated gentamicin. Cross-linked films swell less and became more hydrophilic than chitosan film itself. However, this behavior was inversely proportional to the degree of cross-linking. In vitro gentamicin release from the cross-linked films, at physiological conditions of pH and temperature, was studied for 2 weeks. The effects of gentamicin initial concentration and cross-linking ratio on the kinetics of gentamicin release were evaluated. Results showed that the diffusion rate was governed by initial concentration of gentamicin and degree of cross-linking, since higher gentamicin initial concentration and degree of cross-linking promoted the slower release, while lower gentamicin initial concentration and degree of cross-linking promoted the faster one.     

Effect of poling conditions on growth of calcium phosphate crystal in ferroelectric BaTiO3 ceramics

Recently, ceramic materials have been given a lot of attention as candidates for implant materials, since they possess biologically favorable characteristics for osseointegration. Among them, BaTiO₃ (BTO) ceramics are ferroelectric and piezoelectric after poling treatments. However, little or no information is available on the poling condition of BTO and their effect on calcium phosphate (CaP) formation. In this study, the effect of poling conditions on the formation of CaP layer was investigated. It was observed from this study that CaP was formed on negatively charged BTO surfaces. An increase in Ca/P ratio to 1.67 was observed when the poling temperature was increased above the Curie temperature. On positively charged BTO, no CaP layer was observed.     

Kappa receptor activation attenuates L-trans-pyrrolidine-2,4-dicarboxylic acid-evoked glutamate levels in the striatum

The effects of local kappa receptor activation and blockade on extracellular striatal glutamate levels evoked by reverse microdialysis of L-trans-pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) were investigated. L-trans-PDC elevates extracellular glutamate levels in vivo by acting as a competitive substrate for plasma membrane excitatory amino acid transporters. The selective kappa-opioid receptor agonist U-69593 (1-100 nM) significantly attenuated L-trans-PDC-stimulated glutamate levels in a concentration-dependent manner. The selective kappa receptor antagonist nor-binaltorphimine (1-100 nM) reversed the U-69593-induced decrease in L-trans-PDC-evoked glutamate levels also in a concentration-dependent manner, indicating that the U-69593-induced reduction was mediated by kappa receptor activation. In addition, nor-binaltorphimine significantly elevated basal extracellular glutamate levels, implying that kappa receptors tonically regulate glutamate efflux in the striatum. Previous data from this laboratory have shown that L-trans-PDC-evoked extracellular glutamate levels are partially calcium-sensitive. The present study demonstrated that the inhibition of L-trans-PDC-evoked glutamate levels by reduced calcium perfusion was not altered by U-69593. Therefore, kappa receptors regulate the calcium-dependent component of L-trans-PDC-evoked extracellular glutamate levels in the striatum.