The colloidal stability of fluorescent calcium phosphosilicate nanoparticles: the effects of evaporation and redispersion on particle size distribution

Understanding the colloidal stability of nanoparticles is important for biological applications, such as bio-imaging and drug delivery. This work combines theoretical calculations with experimental data to elucidate the mechanism of stabilization for calcium phosphosilicate nanoparticles containing Cy3 with both citrate and poly(ethylene glycol) (PEG) surface conjugation. The citrate surface is shown to provide electrosteric dispersion in water-ethanol mixtures as well as the ability to redisperse after evaporating the solvent. Improved colloidal stability is afforded with the addition of PEG with respect to redispersion after drying. Changes in average agglomeration number (AAN) are tracked and explained by DLVO and the Napper electrosteric and steric theories for dispersion, respectively.     

Effect of MIL‐53 (Al) MOF particles on the chain mobility and crystallization of poly(L‐lactic acid)

Polymer‐filler interactions significantly influence morphology, functionality, and various desirable properties of mixed matrix membranes (MMMs). In this study, chain mobility and crystallization of poly(l ‐lactic acid) (PLLA) MMM films prepared by solvent casting PLLA with 1, 5, 10, and 20% wt/wt of MIL‐53(Al) metal organic framework (MOF) were evaluated. The fabricated MMMs were characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Differential scanning calorimetry studies indicated that the addition of MOF particles in the PLLA matrix reduces the polymeric chain mobility, which affects the crystallization process. The percent crystallinity of neat PLLA was found to decrease from 4% in neat PLLA to completely amorphous structures in PLLA‐10% and PLLA‐20% MMMs, as observed in the second heating cycle. Fourier transform infrared spectroscopy data supports these observations. Thermogravimetric analysis results showed that PLLA‐MOF films are thermally less stable than neat PLLA suggesting that MOF particles act as a depolymerization catalyst for PLLA. Partial agglomeration of MOF particles was observed in the samples using scanning electron microscopy studies. This study indicates strong PLLA‐MIL‐53(Al) MOF interactions. In addition, this study also provides insight into the effect of MOF particles on the segmental mobility and morphology of PLLA‐MIL‐53 (Al) composite films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45690.     

Assessing the utility of airborne hyperspectral and LiDAR data for species distribution mapping in the coastal Pacific Northwest, Canada

To effectively manage forested ecosystems an accurate characterization of species distribution is required. In this study we assess the utility of hyperspectral Airborne Imaging Spectrometer for Applications (AISA) imagery and small footprint discrete return Light Detection and Ranging (LiDAR) data for mapping 11 tree species in and around the Gulf Islands National Park Reserve, in coastal South-western Canada. Using hyperspectral imagery yielded producer's and user's accuracies for most species ranging from > 52-95.4 and > 63-87.8%, respectively. For species dominated by definable growth stages, pixel-level fusion of hyperspectral imagery with LiDAR-derived height and volumetric canopy profile data increased both producer's (+ 5.1-11.6%) and user's (+ 8.4-18.8%) accuracies. McNemar's tests confirmed that improvements in overall accuracies associated with the inclusion of LiDAR-derived structural information were statistically significant (p < 0.05). This methodology establishes a specific framework for mapping key species with greater detail and accuracy then is possible using conventional approaches (i.e., aerial photograph interpretation), or either technology on its own. Furthermore, in the study area, acquisition and processing costs were lower than a conventional aerial photograph interpretation campaign, making hyperspectral/LiDAR fusion a viable replacement technology.     

Polychronicity, the Internet, and the Mass Media: A Singapore Study

Polychronicity is time-use preference, which people acquire through socialization. The literature shows that polychrons, who favor simultaneous activities, and monochrons, who favor linear activities, exhibit different perceptual and behavioral patterns. This article examines the relationship among polychronicity, Internet skills, Internet use, and Internet perception. In addition, it investigates the hypothesis that Internet use displaces other activity. A total of 1,048 adult Singapore citizens and permanent residents participated in a computer-assisted telephone interview. Of these, 380 were non-Internet users and 668 were users. For the purpose of this study, only responses from the 668 Internet users were included in the analyses. Two-stage least squares regression analyses showed that polychronicity was not associated with Internet use, but it predicted Internet perception. Internet skills positively predicted Internet use and perception. The Internet neither displaced nor promoted television viewing, radio listening, and newspaper reading. However, there was some indication that polychronicity suppressed television viewing.     

Human problems with computer control in process plants

The application of computer control continue to grow. If lessons can be learnt from the incidents that have occurred, they may be prevented from happening again. This paper describes some incidents that have occurred in computer-controlled process plants. The errors are, of course, human errors, failures to foresee or allow for equipment failures or failures to foresee how operators will respond to the equipment. The computers provided new and easier opportunities for making old errors.     

Information technology and regulatory reformThe interorganisational effects of a technological innovation

This paper examines whether information technology can play a strategic role in supporting regulatory reforms aimed at achieving voluntary cooperation with government regulation. Analysis of the case of electronic tax return lodgment in Australia suggests that the effects of IT are contextual, and identifies positive effects of the new IT system on voluntary cooperation. However, in this case, divergence between private and public interests and uncertainty and lack of participation in regulatory decision-making appear to restrict the development of voluntary cooperation as a primary basis for government regulation.     

Automatic dimensional reduction and meshing of stiffened thin-wall structures

The creation of idealised, dimensionally reduced meshes for preliminary design and optimisation remains a time-consuming, manual task. A dimensionally reduced model is ideal for assessing design changes through modification of element properties without the need to create a new geometry or mesh. In this paper, a novel approach for automating the creation of mixed dimensional meshes is presented. The input to the process is a solid model which has been decomposed into a non-manifold assembly of smaller volumes with different meshing significance. Associativity between the original solid model and the dimensionally reduced equivalent is maintained. The approach is validated by means of a free-free modal analysis on an output mesh of a gas turbine engine component of industrial complexity. Extensions and enhancements to this work are also discussed.     

Facet Grammars: Towards static semantic analysis by context-free parsing

Use of executable declarative metalanguages has simplified programming language syntax specification and implementation, whereas existing formalisms for static semantics are still relatively procedural. A working hypothesis is that the context-sensitivity of languages (under static semantic rules) is derived in significant part from the interleaved presences therein of sentences in implicitly-defined and effectively invisible context-free languages. Procedures by which these sentences and context-free grammars for their languages can be respectively derived from the original sentence and the combination of the original language's grammar and semantic rules, lead to the possibility of automatic generation of static semantic analysers from the purely context-free specifications of “Facet Grammars” (FG)!

We show that the utility of FG for static semantic analysis has a non-trivial lower bound, by specifying the relatively complicated identifier scope and accessibility rules for Dijkstra's Guarded Commands Language.     

Web interaction using very small Internet devices

Internet-enabled cell phones typically accommodate only three to 12 text lines, and their design emphasizes portability. Web interaction has, so far, been a secondary concern. For the most part, automated techniques to address the feature gap between the desktop and these phonetops rely on the notion of transducing-translating HTML and images into formats compatible with small devices, which typically cannot handle HTML content. The authors have developed a Web browsing model that supports navigation and action in separate interfaces, To demonstrate the model, they created m-Links, a middleware proxy system that retrieves Web documents using HTTP, lets users navigate and apply services to Web content, and delivers a suitable user interface to a variety of small Web-capable wireless devices.     

Visualising Errors in Animal Pedigree Genotype Data

Genetic analysis of a breeding animal population involves determining the inheritance pattern of genotypes for multiple genetic markers across the individuals in the population pedigree structure. However, experimental pedigree genotype data invariably contains errors in both the pedigree structure and in the associated individual genotypes, introducing inconsistencies into the dataset, rendering them useless for further analysis. The resolution of these errors requires consideration of genotype inheritance patterns in the context of the pedigree structure. Existing pedigree visualisations are typically more suited to human pedigrees and are less suitable for large complex animal pedigrees which may exhibit cross generational inbreeding. Similarly, table‐based viewers of genotype marker data can highlight where errors become apparent but lack the functionality and interactive visual feedback to allow users to locate the origin of errors within the pedigree. In this paper, we detail a design study steered by biologists who work with pedigree data, and describe successive iterations through approaches and prototypes for viewing genotyping errors in the context of a displayed pedigree. We describe how each approach performs with real pedigree genotype data and why eventually we deemed them unsuitable. Finally, a novel prototype visualisation for pedigrees, which we term the ‘sandwich view’, is detailed and we demonstrate how the approach effectively communicates errors in the pedigree context, supporting the biologist in the error identification task.