Dublin City University

About: Dublin City University is a education organization based out in Dublin, Ireland. It is known for research contribution in the topics: Context (language use) & Machine translation. The organization has 5904 authors who have published 17178 publications receiving 389376 citations. The organization is also known as: National Institute for Higher Education, Dublin & DCU.

Spiropyran based hydrogels actuators - walking in the light

Abstract: Herein we report on the synthesis of a bipedal hydrogel walker, based on N-isopropylacrylamide-co-acrylated spiropyran-co-acrylic acid p(NIPAAm-co-SP-co-AA). Due to the presence of the photochromic spiropyran molecule in the polymer structure, these hydrogels reversibly shrink and swell in aqueous environments when exposed to different light conditions. When placed onto a ratcheted surface, the actuation of the bipedal gel produces a walking motion by taking a series of steps in a given direction, as determined by the optimised design of the ratchet scaffold. We anticipate that such biomimetic hydrogel walkers could form the basis of light-actuated soft robots capable of more advanced functions, such as autonomous migration to specific locations accompanied by triggered release of molecular cargo.

Mimicking the electron donor side of Photosystem II in artificial photosynthesis.

Abstract: This review focuses on our recent efforts in synthetic ruthenium–tyrosine–manganese chemistry mimicking the donor side reactions of Photosystem II. Tyrosine and tryptophan residues were linked to ruthenium photosensitizers, which resulted in model complexes for proton-coupled electron transfer from amino acids. A new mechanistic model was proposed and used to design complexes in which the mechanism could be switched between concerted and step-wise proton-coupled electron transfer. Moreover, a manganese dimer linked to a ruthenium complex could be oxidized in three successive steps, from Mn2II,II to Mn2III,IV by the photo-oxidized ruthenium sensitizer. This was possible thanks to a charge compensating ligand exchange in the manganese complex. Detailed studies of the ligand exchange suggested that at high water concentrations, each oxidation step is coupled to a proton-release of water-derived ligands, analogous to the oxidation steps of the manganese cluster of Photosystem II.

X-UV Absorption Spectroscopy with Laser-Produced Plasmas: A Review

Abstract: Exteme-ultraviolet (X-UV) absorption spectroscopy has gained impetus in recent years, spurred on by a growing interest in the physics of core excited atomic, molecular and solid species. Progress in this field has been helped in no small measure by developments in X-UV light sources. One such source is the laser-produced plasma which, by suitable choice of target material, can be used to produce a clean, line free continuum virtually throughout the X-UV and V-UV spectral regions from 40-2000 ?. We briefly address here the issues surrounding the origin and characteristics of laser-plasma continuum light sources. In addition we review progress to date on the application of these sources to the study of the X-UV photoabsorption spectra of atoms, ions and molecules.

Thermo-visual feature fusion for object tracking using multiple spatiogram trackers

Abstract: In this paper, we propose a framework that can efficiently combine features for robust tracking based on fusing the outputs of multiple spatiogram trackers. This is achieved without the exponential increase in storage and processing that other multimodal tracking approaches suffer from. The framework allows the features to be split arbitrarily between the trackers, as well as providing the flexibility to add, remove or dynamically weight features. We derive a mean-shift type algorithm for the framework that allows efficient object tracking with very low computational overhead. We especially target the fusion of thermal infrared and visible spectrum features as the most useful features for automated surveillance applications. Results are shown on multimodal video sequences clearly illustrating the benefits of combining multiple features using our framework.

The clock drawing test in primary care: sensitivity in dementia detection and specificity against normal and depressed elderly.

Abstract: Objectives The aim of this study was to examine the sensitivities and specificities of the clock drawing test (CDT) in the detection of dementia among older people in primary care, with particular emphasis on the effect of depression on CDT specificity. Most previous studies have been sited in specialist settings and few have addressed the issue of specificity aginst depression. Methods Comparison of cohorts identified from community-based screening with GMS-AGECAT. The CDT and the Mini-Mental State Examination (MMSE) were administered to 41 elderly subjects with organic disorder (dementia), 84 elderly subjects with case level depression and 523 normal elderly subjects. Sensitivities and specificities of the CDT were calculated. Results The sensitivity of the CDT in the detection of dementia in the general community was 76%. The specificities of the CDT against normal elderly and depressed elderly was 81% and 77% respectively. Higher sensitivity and specificity were achieved by the MMSE. Conclusions The use of the CDT in the detection of dementia syndromes is likely to be more relevant in the primary care context than in specialist settings. The CDT provides good sensitivity and specificity but may not be as sensitive or specific in the general community as previous studies have suggested, particularly in mild dementia. Community-based late life depression does not appear to alter the specificity of the CDT. Copyright © 2001 John Wiley & Sons, Ltd.