Size distributions of nanoscaled particles and gas temperatures from time-resolved laser-induced-incandescence measurements

Laser-induced-incandescence (LII) signal decays are measured in sooting premixed atmospheric and low-pressure flames. Soot particle temperatures are obtained from LII signals measured at two wavelengths. Soot particle size distributions P(r) and flame temperatures T are measured spatially resolved by independent techniques. Heat and mass transfer kinetics of the LII process are determined from measured soot particle temperatures, flame temperatures, and particle sizes. Uncertainties of current LII models are attributed to processes during the absorption of the laser pulse. Implications for LII experiments are made in order to obtain primary soot particle sizes. Soot particle size distributions and flame temperatures are assessed from measured particle temperature decays by use of multi-D nonlinear regression.     

Physiological functions of FMRFamide-like peptides (FLPs) in crustaceans

Neuropeptides play important roles in chemical signalling in the central and peripheral nervous systems. One of the largest families of neuropeptides is that of the FMRFamide-like peptides (FLPs). This paper reviews what is known about the physiological functions of FLPs in crustaceans, focussing on the cardiovascular, digestive and neuromuscular systems.     

Development of matrix patches for transdermal delivery of a highly lipophilic antiestrogen

The aim of this study was to develop matrix-type transdermal systems (TDSs) containing the highly lipophilic (log P = 5.82) antiestrogen (AE) and the permeation enhancers propylene glycol and lauric acid. For that purpose, permeation of AE from various adhesive matrices through excised skin of hairless mice was evaluated. It was found that pretreatment of the skin with permeation enhancers raised the transdermal flux of subsequently applied antiestrogen. Highest steady-state transdermal fluxes (1.1 µg cm^-2 h^-1) were obtained from Gelva®, polyacrylate adhesive, followed by 0.55 µg cm^-2 h^-1 from Oppanol® polyisobutylene, 0.31 µg cm^-2 h^-1 from BIO-PSA® silicone, and 0.12 µg cm^-2 h^-1 from Sekisui polyacrylate matrices. In order to develop TDS with high content of fluid permeation enhancer propylene glycol, two different strategies were investigated. One strategy was the addition of hydroxypropyl cellulose (HPC) as thickening agent to Gelva matrices. This allowed for propylene glycol loading levels of up to 30%, resulting in transdermal AE fluxes of 0.09 µg cm^-2 h^-1. On the other hand, a fleece-laminated backing foil was loaded with the described permeation enhancer formulation and laminated with polyacrylate adhesive layer, resulting in transdermal AE fluxes of 0.06 µg cm^-2 h^-1. However, application of these TDSs on skin pretreated with permeation enhancers raised the fluxes to 2.6 µg cm^-2 h^-1 from Gelva/HPC and 0.46 µg cm^-2 h^-1 from fleece/Sekisui.     

Theoretical calculations and performance results of a PZT thin film actuator

High piezoelectric coupling coefficients of PZT-based material systems can be employed for actuator functions in micro-electro-mechanical systems (MEMS) offering displacements and forces which outperform standard solutions. This paper presents simulation, fabrication, and development results of a stress-compensated, PZT-coated cantilever concept in which a silicon bulk micromachining process is used in combination with a chemical solution deposition (CSD) technique. Due to an analytical approach and a finite element method (FEM) simulation for a tip displacement of 10 /spl mu/m, the actuator was designed with a cantilever length of 300 /spl mu/m to 1000 /spl mu/m. Special attention was given to the Zr/Ti ratio of the PZT thin films to obtain a high piezoelectric coefficient. For first characterizations X-ray diffraction (XRD), scanning electron microscopy (SEM), hysteresis-, current-voltage I(V)and capacitance-voltage C(V)-measurements were carried out.     

Grain Size Dependence of Electrical Conductivity in Polycrystalline Cerium Oxide

The magnitude and activation energy of electrical conductivity in nanocrystalline cerium oxide exhibit a clear grain size dependence. Experimental results compiled from the literature were analyzed using a space charge model, which takes into account the deviation of point defect concentrations from their bulk values in the vicinity of grain boundaries. The consequences on conductivity arising from such space charge layers were calculated using the brick-layer model (BLM) for grain sizes L large compared to the screening length . The obtained results were supplemented by the calculated conductivity in the flat-band limit for L . This combination allowed for a quantitative comparison with experimental values, which were obtained in the mesoscopic regime of grain sizes from 10–40 nm. The analysis yielded a value for the space charge potential in cerium oxide of 0.55 V. This space charge potential is caused by a reduced standard chemical potential of oxygen vacancies in the grain boundary core as compared to the bulk phase.     

Polyionic fusion peptides function as specific dimerization motifs

The de novo design of a molecular adapter for directed associationand covalent linkage of two polypeptides is presented. Usingpeptides containing charged amino acid residues and an additionalcysteine residue (AlaCysLys₈ and AlaCysGlu₈) we demonstratethat the electrostatic interaction promotes the associationof two synthetic peptides and, subsequently, disulfide bondformation. The reaction depends on both the redox potentialand on the ionic strength of the buffer. Varying the redox potential,the interaction of the peptides was quantified by a G^0' of 6.6± 0.2 kcal/mol. Heterodimerization of the peptides ishighly specific, a competition of association by other cysteinecontaining compounds could not be observed. Two proteins comprisingcysteine-containing polyionic fusion peptides, a modified Fabfragment and an -glucosidase fusion, could be specifically conjugatedby directed association and subsequent disulfide bond formation.Both proteins retain their functional characteristics withinthe bifunctional conjugate: enzymatic activity of the glucosidaseand antigen-binding capacity of the Fab fragment are equivalentto the non-conjugated components.     

Visual recognition of pointing gestures for human–robot interaction

In this paper, we present an approach for recognizing pointing gestures in the context of human–robot interaction. In order to obtain input features for gesture recognition, we perform visual tracking of head, hands and head orientation. Given the images provided by a calibrated stereo camera, color and disparity information are integrated into a multi-hypothesis tracking framework in order to find the 3D-positions of the respective body parts. Based on the hands’ motion, an HMM-based classifier is trained to detect pointing gestures. We show experimentally that the gesture recognition performance can be improved significantly by using information about head orientation as an additional feature. Our system aims at applications in the field of human–robot interaction, where it is important to do run-on recognition in real-time, to allow for robot egomotion and not to rely on manual initialization.     

MAP Estimators for Speech Enhancement Under Normal and Rayleigh Inverse Gaussian Distributions

This paper presents a new class of estimators for speech enhancement in the discrete Fourier transform (DFT) domain, where we consider a multidimensional normal inverse Gaussian (MNIG) distribution for the speech DFT coefficients. The MNIG distribution can model a wide range of processes, from heavy-tailed to less heavy-tailed processes. Under the MNIG distribution complex DFT and amplitude estimators are derived. In contrast to other estimators, the suppression characteristics of the MNIG-based estimators can be adapted online to the underlying distribution of the speech DFT coefficients. Compared to noise suppression algorithms based on preselected super-Gaussian distributions, the MNIG-based complex DFT and amplitude estimators lead to a performance improvement in terms of segmental signal-to-noise ratio (SNR) in the order of 0.3 to 0.6 dB and 0.2 to 0.6 dB, respectively     

On the expression and experience of surprise: No evidence for facial feedback, but evidence for a reverse self-inference effect.

Three studies examined the effects of experimentally manipulated surprise expressions on the experience of surprise. Surprise was induced by a sudden, unannounced change of the stimulus presentation during a computerized task. Facial expression was manipulated by leading participants to adopt an expression akin to surprise, or by forcing them to look up steeply to a monitor. The expression manipulations had no intensifying effect on the experience of surprise, whereas manipulations of unexpectedness and mental load had strong effects. In addition, mental load was found to affect beliefs about facial expression, suggesting that the participants used their feelings of surprise to infer their probable facial displays. Path analyses supported this reverse self-inference hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Melting and crystallization of UHMWPE skived film

Commercial skived film from ultra-high molecular-weight polyethylene (UHMWPE) with considerable uniaxial orientation of lamellae is studied by ultra-small-angle X-ray scattering (USAXS) and wide-angle X-ray scattering (WAXS) during melting and crystallization in order to identify its mechanisms of crystallization. For the analysis of the nanostructure two-dimensional USAXS patterns are analyzed by means of the multidimensional chord distribution function (CDF) method. WAXS shows that crystallization is always isotropic and fast. WAXS reflections are observed before—under certain processing conditions—the SAXS pattern becomes anisotropic. Thus crystallization is decoupled from a slower process of oriented nanostructure formation (nanoforming). If nanoforming is performed isothermally at 105 °C, the evolving nanodomain layers obtain some preferential orientation, as long as the orientation of the melt has not previously been erased by melt-annealing at temperatures of 140 °C or above. Crystallization at temperatures ≥110 °C followed by quenching leads to isotropic nanostructure. Although crystallization is always observed early in the WAXS patterns, the USAXS patterns exhibit only weak discrete scattering during isothermal treatment at temperatures of 110 °C and higher. At 105 °C anisotropic isothermal nanoforming starts after 1.5 min. The melting of the original material resembles an inverted random car-parking mechanism. Only next-neighbor correlations are observed among the crystalline layers. The average nanodomain layer thickness is only slightly increasing (26–30 nm), whereas the long period increase is strong (from 60 nm to 140 nm).