Age and individual differences in prospective memory during a "Virtual Week": The roles of working memory, vigilance, task regularity, and cue focality.

Young (ages 18–22 years) and older (ages 61–87 years) adults (N = 106) played the Virtual Week board game, which involves simulating common prospective memory (PM) tasks of everyday life (e.g., taking medication), and performed working memory (WM) and vigilance tasks. The Virtual Week game includes regular (repeated) and irregular (nonrepeated) PM tasks with cues that are either more or less focal to other ongoing activities. Age differences in PM were reduced for repeated tasks, and performance improved over the course of the week, suggesting retrieval was more spontaneous or habitual. Correlations with WM within each age group were reduced for PM tasks that had more regular or focal cues. WM (but not vigilance) ability was a strong predictor of irregular PM tasks with less focal cues. Taken together, these results support the hypothesis that habitual and focally cued PM tasks are less demanding of attentional resources (specifically, WM), whereas tasks that are more demanding of controlled attentional processes produce larger age differences, which may be attributable to individual differences in WM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lightweight Bytecode Verification

In this paper, we provide a theoretical foundation for and improvements to the existing bytecode verification technology, a critical component of the Java security model, for mobile code used with the Java “micro edition” (J2ME), which is intended for embedded computing devices. In Java, remotely loaded “bytecode” class files are required to be bytecode verified before execution, that is, to undergo a static type analysis that protects the platform's Java run-time system from so-called type confusion attacks such as pointer manipulation. The data flow analysis that performs the verification, however, is beyond the capacity of most embedded devices because of the memory requirements that the typical algorithm will need. We propose to take a proof-carrying code approach to data flow analysis in defining an alternative technique called “lightweight analysis” that uses the notion of a “certificate” to reanalyze a previously analyzed data flow problem, even on poorly resourced platforms. We formally prove that the technique provides the same guarantees as standard bytecode safety verification analysis, in particular that it is “tamper proof” in the sense that the guarantees provided by the analysis cannot be broken by crafting a “false” certificate or by altering the analyzed code. We show how the Java bytecode verifier fits into this framework for an important subset of the Java Virtual Machine; we also show how the resulting “lightweight bytecode verification” technique generalizes and simulates the J2ME verifier (to be expected as Sun's J2ME “K-Virtual machine” verifier was directly based on an early version of this work), as well as Leroy's “on-card bytecode verifier,” which is specifically targeted for Java Cards.     

Accelerating protein release from microparticles for regenerative medicine applications

There is a need to control the spatio-temporal release kinetics of growth factors in order to mitigate current usage of high doses. A novel delivery system, capable of providing both structural support and controlled release kinetics, has been developed from PLGA microparticles. The inclusion of a hydrophilic PLGA–PEG–PLGA triblock copolymer altered release kinetics such that they were decoupled from polymer degradation. A quasi zero order release profile over four weeks was produced using 10% w/w PLGA–PEG–PLGA with 50:50 PLGA whereas complete and sustained release was achieved over ten days using 30% w/w PLGA–PEG–PLGA with 85:15 PLGA and over four days using 30% w/w PLGA–PEG–PLGA with 50:50 PLGA. These three formulations are promising candidates for delivery of growth factors such as BMP-2, PDGF and VEGF. Release profiles were also modified by mixing microparticles of two different formulations providing another route, not previously reported, for controlling release kinetics. This system provides customisable, localised and controlled delivery with adjustable release profiles, which will improve the efficacy and safety of recombinant growth factor delivery.     

Hydrocarbon stress response of four tropical plants in weathered crude oil contaminated soil in microcosms

Responses to hydrocarbon stress of four tropical plants Panicum maximum, Zea mays, Centrosema sp. and Pueraria sp. grown in crude oil contaminated soils (1%, 5% and 10% w/w) were evaluated in a green house. Plants’ percentage survival, shoot heights, biomass development, and phytotoxicity susceptibility were used as indicators of growth, stress response and hydrocarbon tolerance. Relative to control, shoot heights and biomass of plants reduced with increasing hydrocarbon concentration, but 1% w/w oil-in-soil, stimulated shoot heights (5.9% and 6.4%) and weights (21.9% and 2.3%) in P. maximum and Centrosema sp. respectively. P. maximum tolerated the contaminant stress with biomass yields of 113% and 57% of control respectively in 1% and 10% w/w oil-in-soil. All the plants had 100% survival in 1% w/w, but considerably reduced survival in 10% w/w oil-in-soil. These results show that P. maximum has great potential for phytoremediation of petroleum contaminated soil.     

Television as a Design Tool

Television is not only the most powerful medium of communication that our age has produced; it is also the most flexible. Yet its common role in education is that of a mere substitute, called in to mitigate the effects of the shortage of teachers or (to look at the matter historically) the excess of students. That it can be more than that is shown by two University of Nebraska faculty members, describing an experiment in the creative use of television as a tool in the development of that awareness of the characteristics of space which is among the architect's indispensable qualifications.     

Fabrication of high aspect ratio and open‐ended TiO2 nanotube photocatalytic arrays through electrochemical anodization

Well‐aligned, high aspect‐ratio and open‐ended TiO₂ nanotube arrays secured within a Ti foil (TiO₂ nanotubes cartridge) were successfully prepared through the double‐sided anodization method. With ～210 µm of nanotube length, the anodic growth of TiO₂ was accelerated and stabilized by the lactic acid‐containing ethylene glycol electrolyte. In the absence of lactic acid, the anodization led to detachment of nanotubes from the Ti foil after 5–6 h of high voltage (80 V) anodization. Transmission electron microscope image and Raman spectrum revealed that the as‐anodized TiO₂ nanotube arrays without annealing treatment were partially crystalline anatase and demonstrated photocatalytic activity in the mineralization of formic acid. © 2015 American Institute of Chemical Engineers AIChE J, 62: 415–420, 2016     

Interconnectivity and permeability of supercritical fluid-foamed scaffolds and the effect of their structural properties on cell distribution

This study aims to investigate interconnectivity and permeability of scCO₂-foamed scaffolds and the influence of structural scaffold properties on cell distribution. Supercritical fluid technology was utilized to fabricated scaffolds from 37 kDa, 53 kDa and 109 kDa PLGA (85:15). Pore size, pore size distribution and porosity were quantified by MicroCT, and window sizes were measured using SEM. A novel interconnectivity algorithm allowed the quantification of scaffold interconnectivity in three space dimensions. To determine the permeability of porous materials direct perfusion experiments were performed, where a known flow rate was applied to measure the pressure differential across the scaffolds. The permeability was calculated using Darcy's law. Largest pore sizes, porosities, interconnectivities and permeabilities were obtained for scaffolds fabricated from 37 kDa PLGA. These scaffolds showed a heterogeneous pore structure and distribution, whereas homogeneous pore structure, smallest pore sizes, porosities, interconnectivities and permeabilities were observed for scaffolds fabricated from 109 kDa PLGA. The distribution of 3T3 fibroblasts through scCO₂-foamed scaffolds was investigated by MicroCT and MTT staining. Cells were further visualized by fluorescent imaging. Uniform cell distribution was observed on scaffolds fabricated from 109 kDa PLGA and an average of 10% of the total scaffold volume was covered with cells that had adhered onto them.     

Evaporated Te on CdTe: A vacuum-compatible approach to making back contact to CdTe solar cell devices

A commonly used process for forming low-resistance contacts to thin-film p-type CdTe involves the formation of a Te layer by etching the CdTe film in a concentrated mixture of nitric and phosphoric acids. The authors compare evaporated Te back contacts with ‘control’ back contacts formed by the usual etching process, and demonstrate that evaporating Te onto a CdTe thin film is a viable process for forming a low-resistance contact. The best efficiency achieved for a CdTe solar cell made with an evaporated Te back contact is 12.1%, whereas the efficiency of the device made with the control back contact was 11.9%. The evaporation process offers numerous advantages over acid etching, most notably vacuum compatibility amenable to large-scale production of CdTe solar cell modules.