Transmissive electrowetting‐based displays for portable multimedia devices

Abstract— Electrowetting‐based displays have been successfully demonstrated in reflective mode, showing video capability and high optical performance. However, because this technology is based on a high‐efficiency optical switch operating between a light‐absorbing state and a light‐transmitting state, the technology lends itself naturally to a transmissive mode enabling a complete range of applications. This paper describes the first active‐matrix full‐color transmissive electrowetting displays including its main technical and system aspects. Two architectures have been demonstrated: one uses color filters, the other field‐sequential‐color illumination. The paper also introduces alternative concepts for more efficient color transmissive electrowetting displays with multiple absorbing layers.     

The influence of polymer molecular weight in lamellar gels based on PEG-lipids

We report x-ray scattering, rheological, and freeze-fracture and polarizing microscopy studies of a liquid crystalline hydrogel called Lalpha,g. The hydrogel, found in DMPC, pentanol, water, and PEG-DMPE mixtures, differs from traditional hydrogels, which require high MW polymer, are disordered, and gel only at polymer concentrations exceeding an "overlap" concentration. In contrast, the Lalpha,g uses very low-molecular-weight polymer-lipids (1212, 2689, and 5817 g/mole), shows lamellar order, and requires a lower PEG-DMPE concentration to gel as water concentration increases. Significantly, the Lalpha,g contains fluid membranes, unlike Lbeta' gels, which gel via chain ordering. A recent model of gelation in Lalpha phases predicts that polymer-lipids both promote and stabilize defects; these defects, resisting shear in all directions, then produce elasticity. We compare our observations to this model, with particular attention to the dependence of gelation on the PEG MW used. We also use x-ray lineshape analysis of scattering from samples spanning the fluid-gel transition to obtain the elasticity coefficients kappa and B; this analysis demonstrates that although B in particular depends strongly on PEG-DMPE concentration, gelation is uncorrelated to changes in membrane elasticity.     

Dissemination and use of a participatory ergonomics guide for workplaces

Musculoskeletal disorders (MSDs) result in lost-time injury claims and lost productivity worldwide, placing a substantial burden on workers and workplaces. Participatory ergonomics (PE) is a popular approach to reducing MSDs; however, there are challenges to implementing PE programmes. Using evidence to overcome challenges may be helpful but the impacts of doing so are unknown. We sought to disseminate an evidence-based PE tool and to describe its use. An easy-to-use, evidence-based PE Guide was disseminated to workplace parties, who were surveyed about using the tool. The greatest barrier to using the tool was a lack of time. Reported tool use included for training purposes, sharing and integrating the tool into existing programmes. New actions related to tool use included training, defining team responsibilities and suggesting programme implementation steps. Evidence-based tools could help ergonomists overcome some challenges involved in implementing injury reduction programmes such as PE.

Practitioner Summary

Practitioners experience challenges implementing programmes to reduce the burden of MSDs in workplaces. Implementing participatory interventions requires multiple workplace parties to be ‘on-board’. Disseminating and using evidence-based guides may help to overcome these challenges. Using evidence-based tools may help ergonomics practitioners implement PE programmes.     

A new criterion for determining the failure of Ti/SiC metal-matrix composites

The failure of titanium metal-matrix composites (MMCs) strengthened with monofilament carbon-coated sigma SiC fibres has been studied following exposure at a temperature of 900C. Statistical analysis of the data shows that the time to penetration of the carbon layer on the as-received carbon-coated sigma monofilament (SiC+C) can be used as a failure criterion for these composites. The same technique can also be used as a measure of the effectiveness of different diffusion barrier coatings.     

Spatial organization of fish diversity in a species‐rich basin

Many abiotic and biotic environmental characteristics in river basins show spatial gradients from river source to main stem. We examined the spatial organization of fish within the Duck River Basin to document patterns in diversity that could help guide conservation strategies relevant to controlling the detrimental effects of basin development. In all, over 0.33 million fishes representing 145 species and 18 families, including 9 non‐native species, were collected in 207 samples distributed throughout the basin. Main stem sites with large catchment areas supported more fish diversity than smaller sites in tributaries. Moreover, rare species were most common in the main stem and ubiquitous species in tributaries. The spatial organization of species assemblages was mostly nested, as assemblages appeared to disassemble in an upstream direction from main stem sites and confluences. These findings suggest that fish conservation efforts might emphasize main stem segments and confluences that support higher biodiversity including the rare species often most in need of protection. The main stem can support the populations needed to recolonize tributaries and rescue populations that might periodically go extinct after droughts or other major disturbances. In tributaries, conservation of species assemblages may focus on managing between‐patch connectivity via corridor maintenance or creation.     

Analysis of the developing Xenopus tail bud reveals separate phases of gene expression during determination and outgrowth

Fourier-transform infrared spectroscopy (FT-IR) has been applied to the quantitative study of the dehydration of the phosphatidylserine phosphate group in the presence of Ca2+ exerted by different molecules, such as diacylglycerol, sphingosine and stearylarnine, by using a partial least-squares statistical procedure. By using this method it was observed that diacylglycerol enhanced the dehydration of this PO2- group produced by Ca2+ whereas the amino-bases sphingosine and stearylamine protected the phosphate group from the dehydration produced by Ca2+ due to the very strong electrostatic interaction established. The apparent pKa of lipid carboxyl groups can also be estimated by using FTIR. The method consisted in quantifying the absorbance intensities due to the protonated and the unprotonated forms of the specific group being studied. The pKa of the carboxyl group of [1-13C]-palmitic acid included in dipalmitoylphosphatidylcholine membranes was found to be 8.7, a value much higher than that estimated from a molecular solution of the fatty acid. It was observed using the same method that the pKa of free fatty acids in model stratum corneum lipid mixtures was in the range 6.2-7.3 increasing with the preponderance of oleic acid over palmitic acid. Finally the pKa of the carboxyl group of phosphatidylserine was shifted from 4.6 in the pure phospholipid to 2.1 and 2.2 in the presence of equimolar sphingosine and stearylamine, respectively, as a consequence of electrostatic interactions.     

Evidence that tumor necrosis factor alpha converting enzyme is involved in regulated alpha-secretase cleavage of the Alzheimer amyloid protein precursor

The amyloid protein, Abeta, which accumulates in the brains of Alzheimer patients, is derived by proteolysis of the amyloid protein precursor (APP). APP can undergo endoproteolytic processing at three sites, one at the amino terminus of the Abeta domain (beta-cleavage), one within the Abeta domain (alpha-cleavage), and one at the carboxyl terminus of the Abeta domain (gamma-cleavage). The enzymes responsible for these activities have not been unambiguously identified. By the use of gene disruption (knockout), we now demonstrate that TACE (tumor necrosis factor alpha converting enzyme), a member of the ADAM family (a disintegrin and metalloprotease-family) of proteases, plays a central role in regulated alpha-cleavage of APP. Our data suggest that TACE may be the alpha-secretase responsible for the majority of regulated alpha-cleavage in cultured cells. Furthermore, we show that inhibiting this enzyme affects both APP secretion and Abeta formation in cultured cells.