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Arginine-To-Lysine Substitutions Influence Recombinant Horseradish Peroxidase Stability And Immobilisation Effectiveness., Barry Ryan, CiaráN Fagan

Articles

Background: Horseradish Peroxidase (HRP) plays important roles in many biotechnological fields, including diagnostics, biosensors and biocatalysis. Often, it is used in immobilised form. With conventional immobilisation techniques, the enzyme adheres in random orientation: the active site may face the solid phase rather than bulk medium, impeding substrate access and leading to sub-optimal catalytic performance. The ability to immobilise HRP in a directional manner, such that the active site would always face outwards from the insoluble matrix, would maximise the immobilised enzyme’s catalytic potential and could increase HRP’s range of actual and potential applications. Results: We have replaced arginine residues on …

Effects Of Mutations In The Helix G Region Of Horseradish Peroxidase, Barry Ryan, CiaráN Ó'FáGáIn

Articles

Horseradish Peroxidase (HRP) has long attracted intense research interest and is used in many biotechnological fields, including diagnostics, biosensors and biocatalysis. Enhancement of HRP catalytic activity and/or stability would further increase its usefulness. Based on prior art, we substituted solvent-exposed lysine and glutamic acid residues near the proximal helix G (Lys 232, 241; Glu 238, 239) and between helices F and F’ (Lys 174). Three single mutants (K232N, K232F, K241N) demonstrated increased stabilities against heat (up to two-fold) and solvents (up to four-fold). Stability gains are likely due to improved hydrogen bonding and space-fill characteristics introduced by the relevant substitution. …

Computational Trust In Web Content Quality: A Comparative Evalutation On The Wikipedia Project, Pierpaolo Dondio

Articles

The problem of identifying useful and trustworthy information on the World Wide Web is becoming increasingly acute as new tools such as wikis and blogs simplify and democratize publication. It is not hard to predict that in the future the direct reliance on this material will expand and the problem of evaluating the trustworthiness of this kind of content become crucial. The Wikipedia project represents the most successful and discussed example of such online resources. In this paper we present a method to predict Wikipedia articles trustworthiness based on computational trust techniques and a deep domain-specific analysis. Our assumption is …

Pure Non-Blocking Lc Based Matrix Optical Switch For All-Optical Fibre Networks, Yuri Panarin, V. Alex

Articles

New pure non-blocking matrix optical switch scheme for fiber networks is presented. The optical switch is based on conventional LCD technology, where the each pixel controls the polarization state of the light beam. The suggested switch offers several advantages over the conventional cross-point architecture such as: cost; complexity; size; adjustment; and optical performance

The Occipital And Sacral Pressures Experienced By Healthy Volunteers Under Spinal Immobilization: A Trial Of Three Surfaces, Ruairí De Fréin, Fintan Sheerin

Articles

The development of a pressure ulcer is of great significance to the life-long rehabilitative management of the person with a spinal cord injury, and may indeed delay and repeatedly interfere with that process. That the period preceding admission to the specialized spinal injury unit is crucial with regard to pressure ulcer development is evident in the professional literature. Both anecdotal and empirical evidence indicates that a significant number of pressure ulcers occur as a result of management provided prior to admission, and that such ulcers are more likely to occur in those patients who have undergone a transfer process from …

Phenomenographic Study Of Students’ Problem Solving Approaches In Physics, Laura Walsh, Robert Howard, Brian Bowe

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This paper describes ongoing research investigating student approaches to quantitative and qualitative problem solving in physics. This empirical study was conducted using a phenomenographic approach to analyze data from individual semistructured problem solving interviews with 22 introductory college physics students. The main result of the study is a hierarchical set of categories that describe the students’ problem solving approaches in the context of introductory physics.

An Anthology Of Enterprise Policy In Ireland, William Gorman, Thomas Cooney

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Ruane and Gorg (1996: 37) remarked that 'any careful comparison of the Irish economy with other economies in the European Union immediately focuses on two key features of Ireland's pattern of industrial development: the enormous significance of foreign direct investment (FDI) and the very high export ratios in the Irish manufacturing sector among foreign-owned companies. These two features have not developed by accident, but are directly related to the industrial strategy which Ireland has pursued over the past forty years, namely, of promoting export-led growth in Irish manufacturing through various incentives and of encouraging foreign companies to establish manufacturing plants …

A New Approach To The Toxicity Testing Of Carbon-Based Nanomaterials: The Clonogenic Assay, Eva Herzog, Alan Casey, Fiona Lyng, Gordon Chambers, Hugh Byrne, Maria Davoren

Articles

The cellular toxicity of three types of carbon nanoparticles, namely HiPco® single-walled carbon nanotubes (SWCNT), arc dischargeSWCNTand Printex 90 carbon black nanoparticles,was studied on three different cell models including the human alveolar carcinoma epithelial cell line (A549), the normal human bronchial epithelial cell line (BEAS-2B) and the human keratinocyte cell line (HaCaT) using the clonogenic assay. Carbon nanomaterials are known to interact with colorimetric indicator dyes frequently used in cytotoxicity assays. By employing the clonogenic assay, any such interactions could be avoided, allowing a more reliable method for the in vitro toxicity assessment of carbon-based nanoparticles. It could be shown …

Thermal Effectiveness Characteristics Of Low Approach Indirect Evaporative Cooling Systems In Buildings, Ben Costelloe, Donal Finn

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Meteorological enthalpy analysis of temperate and maritime climates above latitude 45°N suggests that the water-side evaporative cooling technique has considerable unrealised potential with contemporary “high temperature” building cooling systems—such as chilled ceilings and displacement ventilation. As low approach conditions are the key to exploiting the cooling potential of the ambient air, thermal performance at such conditions needs to be investigated. To address the research issues, an industrial scale test rig, based on a low approach open cooling tower and plate heat exchanger and designed to maximise evaporative cooling potential, has been constructed. The thermal effectiveness of such systems (as a …

Conformal And Geometric Properties Of The Camassa-Holm Hierarchy, Rossen Ivanov

Articles

Integrable equations with second order Lax pair like KdV and Camassa-Holm (CH) exhibit interesting conformal properties and can be written in terms of the so-called conformal invariants (Schwarz form). These properties for the CH hierarchy are discussed in this ontribution. The squared eigenfunctions of the spectral problem, associated to the Camassa-Holm equation represent a complete basis of functions, which helps to describe the Inverse Scattering Transform (IST) for the Camassa-Holm hierarchy as a Generalised Fourier Transform (GFT). Using GFT we describe explicitly some members of the CH hierarchy, including integrable deformations for the CH equation. Also we show that solutions …

Comparative Evaluation Of Two Models Of Upqc For Suitable Interface To Enhance Power Quality, Malabika Basu, S. P. Das, Gopal Dubey

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Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear loads, which require quality input supply. Also, load current harmonic isolation needs to be ensured for maintaining the quality of the supply current. The present paper describes two control scheme models …

Digital Watermarking And Self-Authentication Using Chirp Coding, Jonathan Blackledge

Articles

This paper discusses a new approach to ‘watermarking’ digital signals using linear frequency modulated or ‘chirp’ coding. The principles underlying this approach are based on the use of a matched filter to provide a reconstruction of a chirped code that is uniquely robust, i.e. in the case of very low signal-to-noise ratios.

Chirp coding for authenticating data is generic in the sense that it can be used for a range of data types and applications (the authentication of speech and audio signals, for example). The theoretical and computational aspects of the matched filter and the properties of a chirp are …

Modelling And Computer Simulation Of Radar Screening Using Plasma Clouds, Jonathan Blackledge

Articles

Following a brief introduction on the principles of screening an aerospace vehicle using a plasma, we develop models for the Impulse Response Functions (IRFs) associated with microwave (Radar) back-scattering from a strong and weakly ionized plasma screen. In the latter case, it is shown that the strength of the return signal is determined by an IRF that is characterised by the simple negative exponential exp(−σ₀t/Є₀) where σ₀ is the average conductivity of the plasma, Є₀ is the permittivity of free space and t is the two-way travel time. For a weakly ionized plasma, the …

Influence Of Electric Field And Light On An Easy Axis Of Nlc Confined By Rectangular Channel At Weak Surface Anchoring, S.V. Pasechnik, A.V. Dubtsov, Yuri Panarin, D.V. Shmeliova, V.A. Tsvetkov, V.G. Chigrinov

Articles

We present new experimental results on combined action of light and electric field on a nematic liquid crystal in a rectangular channel at a weak surface anchoring. The first experimental study of slow surface dynamics at combined action of electric field and polarized light in new experimental geometry was performed. Influence of polarized light on spatial twist-like deformation of a director field induced by electric field was established.

Experimental Study For The Conditions Of Analog Switching In Ferroelectric Liquid Crystal Cells, V. Manjuladevi, Yuri Panarin, J.K. Vij

Articles

The authors study the effect of the spontaneous polarization (PS) of a ferroelectric liquid crystal mixture with compensated helix and of the thickness of the alignment layer (da) on the analog switching in a cell. The quality of analog switching is established in terms of its contrast ratio, texture in the dark state, and the electrostatic energy. The latter approximates to PS 2da for da

Discontinuous Change In The Smectic Layer Thickness In Ferrielectric Liquid Crystals, V. P. Panov, J. K. Vij, Yuri Panarin, C. Blanc, V. Lorman, J. W. Goodby

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The temperature dependence of the thickness of thick free-standing films is studied using a high-resolution film thickness measurement technique. A small discontinuity in the temperature dependence of the smectic layer thickness at every phase transition between ferro-, ferri-, and antiferroelectric phases is observed. We show that the major contribution to it arises from a change in the smectic tilt angle.

The Role Of Spontaneous Polarization And The Thickness Of Alignment Layers On The V-Shaped Switching In Flc Cells, V. Manjuladevi, J.K. Vij, Yuri Panarin

Articles

Ferroelectric liquid crystal mixtures with the various values of spontaneous polarizations were prepared, and the substrates were coated with different thicknesses of aligning agent. The frequency dependence of the electrooptic response of these materials in cells with various thickness of alignment layers has been measured. The coercive voltage as well as the contrast ratios are calculated. Our results support the ‘‘electrostatic model’’, according to which both the value of spontaneous polarization and the thickness of the alignment layer play important roles in the V-shaped switching.

Colour Doppler Spatial Resolution Performance Testing, Jacinta Browne, Ian Brown, Peter Hoskins, Amanda Watson, Alex Elliott

Articles

No abstract available

Photoinduced Surface Relief Studies In An Acrylamide-Based Photopolymer, Pavani Kotakonda, Izabela Naydenova, Suzanne Martin, Vincent Toal

Articles

Surface relief gratings (SRGs) have been optically recorded in a dry, self-developing acrylamide-based photopolymer. An investigation of the dependence of photoinduced surface relief amplitude and profile on recording intensity, UV post-exposure, thickness of the sample, composition of the photopolymer and temperature at constant spatial frequency was carried out using white light interferometry. Non-sinusoidal surface relief grating profiles which depend on sample thickness were observed at low spatial frequency. The surface relief effect is intended to be applied to the alignment of liquid crystals (LCs) for different applications such as voltage controllable diffraction gratings, lenses, polarizing components and switches.

A Novel Wideband Semi-Planar Miniaturized Antenna, Giuseppe Ruvio, Max Ammann

Articles

A semi-planar miniaturized antenna which operates over the FCC allocated UWB spectrum is presented. The small antenna comprises a folded conducting element connected to a printed section. Several solutions are introduced which create different current paths increasing the effective dimensions of the antenna. The antenna is examined for the stand-alone case and for the antenna mounted in various locations on a larger handset-type groundplane. The impedance and radiation characteristics show a relative independence of the groundplane size and the antenna location on it. The proposed antenna is a valuable candidate for handset applications due to its compactness. The proposed antenna …

Macrobending Fiber Loss Filter, Ratiometric Wavelength Measurement And Application, Qian Wang, Ginu Rajan, Gerald Farrell, Pengfei Wang, Yuliya Semenova, Thomas Freir

Articles

A macrobending standard single-mode fibre (SMF28) is optimized as an edge filter, with the optimal bending radius and length determined according to the bend loss and polarization sensitivity of the bending fibre. An all-fibre ratiometric wavelength system is built and calibrated. The system's accuracy and resolution is discussed with the influence of noise of input signal and photodetectors. Finally, the ratiometric system is employed for the demodulation of FBG strain sensing.

Quantum Dot Energy Relaxation Mediated By Plasmon Emission In Doped Covalent Semiconductor Heterostructures, A. V. Fedorov, Anna Baranov, I. D. Rukhlenko, T. S. Perova, Kevin Berwick

Articles

The interaction between interface plasmons within a doped substrate and quantum dot electrons or holes has been theoretically studied in double heterostructures based on covalent semiconductors. The interface plasmon modes, the corresponding dispersion relationship, and the intraband carrier relaxation rate in quantum dots are reported. We find the critical points in the interface plasmon density of states for multilayered structures results in enhanced quantum dot intraband carrier relaxation when compared to that for a single heterostructure. A detailed discussion is made of the relaxation rate and the spectral position dependencies on the quantum dot layer thickness as well as on …

An Approach To Unification Using A Linear Systems Model For The Propagation Of Broad-Band Signals, Jonathan Blackledge

Articles

We review the inhomogeneous scalar Helmholtz equation in three-dimensions and the scattering of scalar wavefields from a scatterer of compact support. An asymptotic solution is then considered representing the effect of the frequency approaching zero when a ‘wavefield’ reduces to a ‘field’. The characteristics of ultra-low frequency Helmholtz scattering are then considered and the physical significance discussed of a model that is based on the scattering of Helmholtz wavefields over a broad frequency spectrum. This is equivalent to using a linear systems approach for modelling the propagation, interaction and detection of broad-band signals and provides an approach to the classification …

Diffusion And Fractional Diffusion Based Models For Multiple Light Scattering And Image Analysis, Jonathan Blackledge

Articles

This paper considers a fractional light diffusion model as an approach to characterizing the case when intermediate scattering processes are present, i.e. the scattering regime is neither strong nor weak. In order to introduce the basis for this approach, we revisit the elements of formal scattering theory and the classical diffusion problem in terms of solutions to the inhomogeneous wave and diffusion equations respectively. We then address the significance of these equations in terms of a random walk model for multiple scattering. This leads to the proposition of a fractional diffusion equation for modelling intermediate strength scattering that is based …

Optical Performance Of Non-Blocking 4x4 Optical Switch: Simulation And Experiment, V. Alex, A. Dubtsov, Yuri Panarin, T. Wilkinson

Articles

A prototype of pure non-blocking 4x4 optical LC switch was designed and built. This switch is based on conventional LCD technology, where the each pixel controlled the polarization state of the light beam. An addressing algorithm was described. The optical performance of the switch, such as cross-talk and insertion loss, was simulated and experimentally studied. The suggested approach offers several advantages over the conventional cross-point architecture such as: cost; complexity; size; adjustment; and optical performance.

Microstructures And Viscoelastic Properties Of Anisotropic Magnetorheological Elastomers, Lin Chen

Articles

The microstructures and viscoelastic properties of anisotropic magnetorheological elastomers were investigated in this paper. The measurement results show that their mechanical properties are greatly dependent on the magnetic flux density applied in preparation. A finite-column model was proposed to describe the relations between the microstructures and the viscoelastic properties. The simulation results agree well with the experimental results.

Investigation On Magnetorheological Elastomers Based On Natural Rubber, Lin Chen

Articles

Magnetorheological Elastomers (MR Elastomers or MREs) are a kind of novel smart material, whose mechanical, electrical, magnetic properties are controllable under applied magnetic fields. They have attracted increasing attentions and broad application prospects. But conventional MREs are limited to wide applications because their MR effects and mechanical performances are not high enough. This paper aims to optimize the fabrication method and to fabricate good natural rubber based MREs with high modulus by investigating the influences of a variety of fabrication conditions on the MREs performances, such as matrix type, external magnetic flux density, and temperature, plasticizer and iron particles. Among …

Simultaneous Modelling Of The Thermal Degradationa Kinetics Of Pectin, Daniel Rico, Ana Belen Martin-Diana, Catherine Barry-Ryan, Gary Henehan, Jesus Maria Frias

Articles

The thermal degradation kinetics of pectin methylesterase (PME) from carrot and lettuce were studied. Fresh extracts were exposed to temperatures from 55 to 70 °C until the enzyme was inactivated. A model based on the presence of two forms of the enzyme, one active and one non-active, is proposed. The natural variability of the PME activity was taken into the model in the form of normally distributed random effects. The common model parameters obtained (cleavage constant (0.0395±0.0062 s⁻¹), degradation constant (0.556±0.112 s⁻¹), cleavage energy of activation (469±23 kJ mol⁻¹) and degradation energy of activation …

Ef Fi Cacy Of Steamer Jet-Injection As Alternative To Chlorine In Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Jesus Maria Frias, J. Barat, Gary Henehan, Catherine Barry-Ryan

Articles

The use of calcium lactate solutions has been shown to be a healthy alternative to chlorine washing in order to maintain the shelf-life of fresh-cut products. The aim of this research was to analyse the effects of calcium lactate (15 g L⁻¹) treatment at 25 °C and 50 °C (heat-shock) on the textural properties of sliced carrots and to compare those with the chlorine treatment (120 mg L⁻¹) widely used in industry. Several direct and indirect markers of textural changes in carrots during storage were used: Instron textural analysis, Cryo-SEM and optical microscopic, sensory analysis, pectin …

Extending And Measuring The Quality Of Fresh-Cut Fruit And Vegetables: A Review, Ana Belen Martin-Diana, Daniel Rico, Gary Henehan, Jesus Maria Frias, J. Barat

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The market sales of ready - to - use vegetables have grown rapidly in recent decades as a result of changes in consumer attitudes especially consumption of fresh-cut lettuce and carrot due to their use in prepared salads. Chlorine solutions have been widely used to sanitise fruit and vegetables in the fresh-cut industry. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing. There is a real need to find alternatives for preservation of fresh-cut fruit and vegetables in order to improve the efficacy …