Thermoresponsive Complex Coacervate‐Based Underwater Adhesive

Sandcastle worms have developed protein‐based adhesives, which they use to construct protective tubes from sand grains and shell bits. A key element in the adhesive delivery is the formation of a fluidic complex coacervate phase. After delivery, the adhesive transforms into a solid upon an external trigger. In this work, a fully synthetic in situ setting adhesive based on complex coacervation is reported by mimicking the main features of the sandcastle worm's glue. The adhesive consists of oppositely charged polyelectrolytes grafted with thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM) chains and starts out as a fluid complex coacervate that can be injected at room temperature. Upon increasing the temperature above the lower critical solution temperature of PNIPAM, the complex coacervate transitions into a nonflowing hydrogel while preserving its volume—the water content in the material stays constant. The adhesive functions in the presence of water and bonds to different surfaces regardless of their charge. This type of adhesive avoids many of the problems of current underwater adhesives and may be useful to bond biological tissues.     

Integrating imaging spectroscopy (445–2543 nm) and geographic information systems for post-disaster management: a case of hailstorm damage in Sydney

This paper demonstrates a methodology for the analysis and integration of airborne hyperspectral sensor data (445–2543?nm) with GIS data in order to develop a vulnerability map which has the potential to assist in decision making during post-disaster emergency operations. Hailstorms pose a threat to people as well as property in Sydney, Australia. Emergency planning demands current, large-scale spatio-temporal information on urban areas that may be susceptible to hailstones. Several regions, dominated by less resistant roofing materials, have a higher vulnerability to hailstorm damage than others. Post-disaster operations must focus on allocating dynamic resources to these areas. Remote sensing data, particularly airborne hyperspectral sensor data, consist of spectral bands with narrow bandwidths, and have the potential to quantify and distinguish between urban features such as roofing materials and other man-made features. A spectral library of surface materials from urban areas was created by using a full range spectroradiometer. The image was atmospherically corrected using the empirical line method. A spectral angle mapper (SAM) method, which is an automated method for comparing image spectra to laboratory spectra, was used to develop a classification map that shows the distribution of roofing materials with different resistances to hailstones. Surface truthing yielded high percentage accuracy. Spatial overlay technique was performed in a GIS environment where several types of cartographic data such as special hazard locations, population density, data about less mobile people and the street network were overlaid on the classified geo-referenced hyperspectral image. The integrated database product, which merges high quality spectral information and cartographic GIS data, has vast potential to assist emergency organizations, city planners and decision makers in formulating plans and strategies for resource management.     

Are there cultural differences in how we play? Examining cultural effects on playing social network games

Digital games embedded in social network sites are one of the driving forces behind the expansion of digital gamer populations. Previous studies have observed different usage patterns between users in different ethnic groups and countries, suggesting that culture orientations may affect how people play and interact through social network games. This study examined how people’s culture orientations affect usage patterns with measures of vertical and horizontal individualism–collectivism. The findings indicate that culture does not directly affect usage patterns. Instead, the effects on usage patterns are mediated by people’s expected outcomes of playing social network games. Vertical culture orientations predicted social expected outcomes. Individualism predicted status expected outcomes, but in different directions on the dimensions of vertical or horizontalness. Vertical collectivism was the only culture orientation that indirectly predicted buying in-game products with real money. Implications for game designers and markers are discussed.     

Structural,morphological and opto-electric properties of Y2−xYbxO3 (x = 0.0, 0.04, 0.08, 0.12) nanopowders for laser host ceramic material applications

Journal of Materials Science: Materials in Electronics - Rare Earth substituted Sesquioxides compounds, specially Yttria (Y2O3) are essential ceramic materials for solid-state lasers,...     

Student use of Facebook for organizing collaborative classroom activities

Social network sites such as Facebook are often conceived of as purely social spaces; however, as these sites have evolved, so have the ways in which students are using them. In this study, we examine how undergraduate students use the social network site Facebook to engage in classroom-related collaborative activities (e.g., arranging study groups, learning about course processes) to show how Facebook may be used as an informal tool that students use to organize their classroom experiences, and explore the factors that predict type of use. Data from two surveys (N = 302, N = 214) are used to analyze how Facebook use, social and psychological factors, self-efficacy, and types of instructor-student communication on Facebook are related to positive and negative collaboration among students. We found that predictors of Facebook use for class organizing behaviors include self-efficacy and perceived motivation to communicate with others using the site. When placed in the context of social and psychological factors, Facebook intensity did not predict either positive or negative collaboration, suggesting that how students used the site, rather than how often they used the tool or how important they felt it was, affected their propensity to collaborate.     

Identification of Seeds by Colour Imaging: Comparison of Discriminant Analysis and Artificial Neural Network

This study describes the use of colour image analysis to identify four seed varieties. A wide range of kernel measurements was obtained from digitised colour images of whole seed samples of rumex, wild oat, lucerne and vetch. The combination size, shape (including kernel seven invariant moments) and texture parameters is the major element in this investigation. Two pattern recognition approaches were attempted in the classification: stepwise discriminant analysis, which is part of statistical pattern recognition techniques, and artificial neural network. The artificial neural network was found to outperform discriminant analysis. With only three inputs, a simple three-layer perception network exhibited performances exceeding 99% both in learning and test sets. It is shown that a mixture of features improved classification from 92% for size and shape parameters to 99% for size, shape and texture parameters. Two species, totally overlapped in the morphometrical space, were well separated by texture. The best characteristics are extracted from the red channel images. Limitations of neural computing concepts are discussed with respect to seed classification.     

Open- and short-circuit thermally stimulated currents in ethyl cellulose

Thermally stimulated currents (TSCs) in short-circuit and open-circuit configuration for ethyl cellulose samples (≈40 µm thick) have been studied as a function of polarizing field (25–100kV/cm) and polarizing temperature (323–353K). The thermograms have been found to be characterized by two prominent peaks located around 70 ± 10°C and 140 ± 10°C and the appearance of anomalous current in the high temperature region of the short-circuit TSC thermograms. The observed behaviour has been explained in terms of the existence of heterocharge due to dipole orientation and ionic homocharge drift, together with the injection of charge carriers from electrodes and their subsequent localization in surface and bulk traps.     

New Carbohydrate‐Based Phosphite‐Oxazoline Ligands as Highly Versatile Ligands for Palladium‐Catalyzed Allylic Substitution Reactions

We have designed and synthesized a new family of readily available phosphite‐oxazoline ligands for Pd‐catalyzed asymmetric allylic substitution reactions. These ligands can be tuned in two regions to explore their effect on catalytic performance. By carefully selecting the ligand components, we obtained high enantioselectivities in the Pd‐catalyzed allylic substitution in substrates with different steric properties