In the present contribution we report on a novel route to synthesize 2D-polyaniline (2DPAN) on sulfonated-poly(styrene) (SPS) templates by allowing first monomer assembly followed by chemical oxidation to achieve polymerization. We show that Aplysia neurons grown on 2D-PAN exhibit an unusual growth pattern and adhesion to this conducting substrate that is manifested by the formation of giant lamellipodia. The lamellipodial domains are characterized by small gap between the plasma membrane and the 2D-PAN substrate (ca. 30 nm) and actin rich skeleton resembling the skeleton of growth cones. This behavior is characteristic to uniform substrates containing only 2DPAN. However, in patterned substrates containing additionally poly(L-lysine) Aplysia neurons prefer to extend new neurites on the poly(L-lysine) domains.
A novel electrochem. method for deposition of ZrO2 thin films is described. The films, 50-600 nm thick, were obtained by applying moderate pos. or neg. potentials (+ 2.5 V to -1.5 V vs. SHE) on conducting surfaces immersed in a 2-propanol soln. of zirconium tetra-n-propoxide [Zr(OPr)4] in the presence of minute quantities of water (water/monomer molar ratios in the range of 10-5 to 10-1), which was the limiting reagent. Oxidative electrochem. formation of solvated H+ and reductive formation of OH- catalyze the hydrolysis and condensation of the metal alkoxide precursor. The magnitude of the applied potential and its duration provide a convenient way of controlling the film thickness. The films consist of an amorphous phase, as revealed by XRD measurements. The effects of different parameters, such as the applied potential and its duration, the amt. of added water and the current-time characteristics, were studied. A mechanism for the electrodeposition of the zirconia films which is in accordance with our findings is proposed. [on SciFinder(R)]
A novel electrochemical method for deposition of ZrO(2) thin films is described. The films, 50-600 nm thick, were obtained by applying moderate positive or negative potentials (+2.5 V to -1.5 V versus SHE) on conducting surfaces immersed in a 2-propanol solution of zirconium tetra-n-propoxide [Zr(OPr)(4)] in the presence of minute quantities of water (water/monomer molar ratios in the range of 10(-5) to 10(-1)), which was the limiting reagent. Oxidative electrochemical formation of solvated H(+) and reductive formation of OH(-) catalyze the hydrolysis and condensation of the metal alkoxide precursor. The magnitude of the applied potential and its duration provide a convenient way of controlling the film thickness. The films consist of an amorphous phase, as revealed by XRD measurements. The effects of different parameters, such as the applied potential and its duration, the amount of added water and the current-time characteristics, were studied. A mechanism for the electrodeposition of the zirconia films which is in accordance with our findings is proposed.[on SciFinder (R)]
We extend our novel low-voltage electrochem. method for oxide thin film formation from sol-gel monomers to include entrapment of org. mols. within the films. We also describe an extension of the method to titania thin films, which are obtained from titanium tetra-n-propoxide in alc. solns. by applying potentials in the range of +2.0 to -1.4 V to indium tin oxide electrodes. The film thickness (ranging between 20-1000 nm) is controllable by changing either the potential or the duration of its application. We demonstrate that this electrochem. method provides a convenient way for entrapment of org. dopants within the film. Four dyes were used for that purpose: Basic Blue 41, methylene-blue, tris(2,2'-bipyridine)iron(II) and tris(2,2'-bipyridine)ruthenium(II). [on SciFinder(R)]
We study ordered arrays of Quantum Dots (QDs) as model systems for the electronic structure and response of solids and devices built from nanoscale components. QDs self-assemble as two-dimensional solids, with novel optical and electric properties, which can be experimentally tuned. The properties are controlled chemically via the selection of the composition and size of the individual QDs and physically through such external controls as the packing, temperature, and electrical and magnetic fields. The freedom of the architectural design is constrained because even the best synthesis does not yield dots of exactly the same size. We discuss the effects of disorder on the electronic structure of arrays of metallic dots and on their transport properties. (C) 2004 Wiley Periodicals, Inc.
Nanoshells have been previously shown to have tunable absorption frequencies that are dependent on the ratio of their inner and outer radii. Inspired by this, we ask: can a nanoshell increase the absorption of a small core system embedded within it? A theoretical model is constructed to answer this question. A core, composed of a “jellium” ball of the density of gold is embedded within a jellium nanoshell of nanometric diameter. The shell plasmon frequency is tuned to the core absorption line. A calculation based the time-dependent density functional theory was performed showing a 10 fold increase in core excitation yield.
The ability of a mixed lipid bilayer composed of neutral and charged lipids to encapsulate an oppositely charged protein is studied with use of a simple theoretical model. The free energy of the bilayer-enveloped protein complex is expressed as a sum of electrostatic and curvature elasticity contributions, and compared to that of a protein adsorbed on a mixed planar bilayer. The electrostatic adsorption energy on the planar bilayer is calculated by using an extended Poisson-Boltzmann approach, which allows for local lipid charge modulation in the adsorption zone. We find that the electrostatic interactions favor the wrapped state, while the bending energy prefers the planar bilayer. To enable the transition from the adsorbed to enveloped protein geometry, there is a minimal necessary protein charge. This ``crossover'' charge depends on the bending rigidity of the lipid membrane and the (composition dependent) spontaneous curvature of its constituent monolayers. The values for the crossover charge predicted by the theory are in line with the charge necessary for peptide shuttles to penetrate cell membranes.
Esther Schely-Newman Our Lives Are But Stories: Narratives of Tunisian-Israeli Women Detroit: Wayne State University Press, 2002 Our Lives Are But Stories is the biography of a generation of Jewish [...]
Existing studies of the trend towards electronic provision of travel services tend to be highly bifurcated. They focus either on the supply-side characteristics of this change (new technologies and mediation platforms) or on the demand-side attributes, such as the socio-economic profile of the Internet user and attitudes towards electronic purchasing in the travel market. The latter approach, however, can lead to sample selectivity bias and misleading parameter estimates. It fails to recognize that actual Internet travel purchases are observable only for individuals who have made the prior decision to use the Internet as a market intermediary. This paper addresses this drawback by modelling the decision to purchase travel products on the Internet in a bivariate probit framework. The choice of travel service intermediary, travel agent (face-to-face) or Internet (cyberspace), is determined by the joint probabilities of general Internet purchasing and specific Internet travel purchasing. Using unique survey evidence of actual Internet transactions, the discrepancies between preferences for Internet travel purchasing and actual travel purchases are highlighted. The results suggest that demand for the latter is more closely related to previous Internet purchasing experience than to the socio-economic attributes of the purchaser.
The clinical spectrum of cystic fibrosis (CF) is influenced by the cystic fibrosis transmembrane conductance regulator (CFTR) genotype. However, variable courses of the disease were demonstrated among patients with identical genotypes. Since siblings share identical CFTR mutations and environmental factors, they can serve as a model to assess the effect of modifier genes on disease expression, and also to evaluate cross-infection. The aim of this study was to compare disease expression among siblings with CF. All sibling pairs treated at 7 CF centers in Israel were included in the study. Data were collected from patients' medical charts. Fifty families with at least 2 siblings were identified. As expected, the second-born sibling was diagnosed at an earlier age compared to the first-born. The mode of CF presentation at diagnosis showed significant familial concordance. In the families where the first sibling presented with gastrointestinal manifestations, 79% of the second siblings also presented with gastrointestinal manifestations. When gastrointestinal manifestations were absent in the first sibling, only 12% of the second siblings presented with gastrointestinal manifestations (P < 0.0001). Likewise, when the first sibling presented with respiratory symptoms, 60% of the second siblings presented with the similar symptoms. However, when the first sibling presented without respiratory symptoms, only 12% of the second siblings presented with respiratory symptoms (P < 0.001). Meconium ileus (MI) was present in 20 patients (21%). In 10 families where the first-born sibling had MI, 8 (80%) of the subsequent siblings had MI. On the other hand, in the 39 families where the first-born sibling did not have MI, only 2 (5%) subsequent siblings had MI (P < 0.001). Pancreatic insufficiency (PI) also had high familial concordance (P < 0.0001). Percentile growth for weights and heights and lung function (FVC, FEV(1), and FEF(25-75)) at ages 7 and 10 years were similar between siblings. P. aeruginosa grew from sputum in 89% of our study patients. When P. aeruginosa was isolated from the first-born patient, 91% of the second siblings were also positive for P. aeruginosa, whereas when the initial sibling was not a carrier of P. aeruginosa, only 50% of subsequent siblings were positive (P < 0.0001). This familial concordance was not observed for S. aureus. By contrast, the age of first isolation of P. aeruginosa and S. aureus was significantly earlier in the second sibling than in the first for the two bacteria: 10.3 +/- 5.1 vs. 7.3 +/- 5.2 years (P < 0.05) for P. aeruginosa, and 11.5 +/- 5.4 years vs. 6.8 +/- 5.1 years (P < 0.05) for S. aureus. CF siblings tend to share similar phenotypes that are not mutation-dependent. The lack of variability between siblings in mode of initial CF presentation, rates of MI, pulmonary function, and nutritional status supports the role of modifier genes in the determination of these factors.
D Van-Dijk and AN Kluger. 2004. “Feedback sign effect on motivation: Is it moderated by regulatory focus?.” Applied Psychology-an International Review-Psychologie Appliquee-Revue InternationaleApplied Psychology-an International Review-Psychologie Appliquee-Revue Internationale, 53, Pp. 113-135.
D Van-Dijk and AN Kluger. 2004. “Feedback sign effect on motivation: Is it moderated by regulatory focus?.” Applied Psychology-an International Review-Psychologie Appliquee-Revue InternationaleApplied Psychology-an International Review-Psychologie Appliquee-Revue Internationale, 53, Pp. 113-135.
D Van-Dijk and AN Kluger. 2004. “Feedback sign effect on motivation: Is it moderated by regulatory focus?.” Applied Psychology-an International Review-Psychologie Appliquee-Revue InternationaleApplied Psychology-an International Review-Psychologie Appliquee-Revue InternationaleApplied Psychology-an International Review-Psychologie Appliquee-Revue Internationale, 53, Pp. 113-135. Abstract
Despite our common sense notion that indicates that feedback sign (positive vs. negative) has a decisive effect on motivation, the vast literature has no clear specifications regarding when and how positive (negative) feedback increases or decreases motivation (e.g. Kluger & DeNisi, 1996). The variability in feedback sign effects can be explained by self-regulation theory (Higgins, 1997, 1998). Specifically, relatively high levels of motivation are induced either by failure under prevention focus (failure to meet obligations) or by success under promotion focus (fulfilling a desire). In two experiments, regulatory focus was operationalised by a manipulation of situational factors (scenarios) and by three measures of individual differences (values, occupations, and the motives for choosing one's job). Results from these experiments corroborated the hypotheses with all the different operationalisations. Future experiments should investigate the possible three-way interaction between situational regulatory focus, chronic regulatory focus, and feedback sign.
