Physical Sciences and Mathematics Commons^™

Prevention Of Staphylococcus Epidermidis Biofilm Formation Using A Low-Temperature Processed Silver-Doped Phenyltriethoxysilane Sol–Gel Coating, Niall Stobie, Brendan Duffy, Declan Mccormack, John Colreavy, Martha Hidalgo, Patrick Mchale, Steven Hinder

Articles

Sol–gel coatings which elute bioactive silver ions are presented as a potential solution to the problem of biofilm formation on indwelling surfaces. There is evidence that high-temperature processing of such materials can lead to diffusion of silver away from the coating surface, reducing the amount of available silver. In this study, we report the biofilm inhibition of a Staphylococcus epidermidis biofilm using a low-temperature processed silver-doped phenyltriethoxysilane sol–gel coating. The incorporation of a silver salt into a sol–gel matrix resulted in an initial high release of silver in de-ionised water and physiological buffered saline (PBS), followed by a lower sustained …

Evaluation Of Robocode As A Teaching Tool For Computer Programming, Arnold Hensman

Conference Papers

Robocode began as an educational tool to aid in learning Java programming. It has since evolved into something of a phenomenon, as the prospect of creating simple to complex virtual tanks appears to pose an attractive challenge to both novice and expert programmers alike. What started out as a teaching tool has grown into a worldwide network of competitors, all keen to prove that their ‘bot’ stands out from the crowd. Competitions are well organised and many Robocode events are a PR dream for the computing companies that sponsor them. Without a doubt, this easy to use application has sparked …

The Development Of A Quality Risk Management Solution Designed To Facilitate Compliance With The Risk-Based Qualification, Validation And Change Control Gmp Requirement Of The Eu, Kevin O'Donnell

Doctoral

This research work was concerned with investigating the risk-based regulatory requirements that are currently in place in the European Union governing the manufacture of medicinal products. The main goal of this research was to develop a practical Quality Risk Management methodology that served as a solution for facilitating compliance with the EU GMP requirements in the area of risk-based Qualification, Validation and Change Control, and which was fully in line with the principles and guidance of ICH Q9, on Quality Risk Management. Following extensive testing and evaluation activities with a range of key stakeholders including the pharmaceutical manufacturing sector in …

Practical Sensor For Measurement Of Nitrogen, Dusan Popovic, Vladimir Milosavljevic, Steven Daniels

Articles

This paper presents a method for precise measurement of atomic and molecular nitrogen in an oxygen-nitrogen dc plasma. This is achieved by monitoring the intensities of the atomic nitrogen spectral line at 821.6 nm and the molecular nitrogen bandhead at 337.1 nm, relative to the atomic oxygen spectral line at 844.7 nm. Oxygen is one of the most frequently used gases for surface chemical treatment, including deposition and etching, therefore the ability to measure and control the process and chemical composition of the process is essential. To validate this oxygen actimometry method for N2-xO2 (where x varies from 0 to …

An Examination Of The Bystander Effect In Multiple Models: From Cell Line To In-Vivo Exposure, Alice Vines

Doctoral

In recent years there has been a paradigm shift in radiobiology, to one which induces non-targeted effects, such as the bystander effect and genomic instability. The bystander effect has been defined as effects seen in cells that although never exposed to radiation, display similar effects to those that have, due to some form of communication with directly hit cells. This investigation aims to further the current understanding of this effect using three different models, cell lines, primary explant cultures and whole animals. Multiple cell lines were used to determine the relative importance of bystander signal production versus the response in …

Integrated Approach To The Toxicity Evaluation Of Irish Marine Sediments: Exotoxicological Assessment, Ailbhe Macken

Doctoral

The quality of sediment in any aquatic ecosystem is vital to the health of that system. Sediments have been recognised as a major repository for persistent toxic substances. If sediments become sufficiently polluted they can lead to the disruption of surrounding natural biological communities. Therefore the monitoring of sediment quality is essential for successful ecosystem functioning in the marine environment. The aim of the present study was to employ an integrated approach of the toxicity evaluation of Irish marine sediments by correlating results of biotests with chemical analysis. Between 2004 and 2006 the Radiation and Environmental Science Centre (RESC) participate …

A Cosmic Ray Current-Driven Instability In Partially Ionised Media, Brian Reville, John Kirk, Peter Duffy, Stephen O'Sullivan

Articles

We investigate the growth of hydromagnetic waves driven by streaming cosmic rays in the precursor environment of a supernova remnant shock. It is known that transverse waves propagating parallel to the mean magnetic field are unstable to anisotropies in the cosmic ray distribution, and may provide a mechanism to substantially amplify the ambient magnetic field. We quantify the extent to which temperature and ionisation fractions modify this picture. Using a kinetic description of the plasma we derive the dispersion relation for a collisionless thermal plasma with a streaming cosmic ray current. Fluid equations are then used to discuss the effects …

How Fat Layers Affect The Clinical Diagnosis From Doppler Data, Deirdre King, Carmel Moran, Matt Hussey, Jacinta Browne

Conference Papers

Ultrasound Doppler data are routinely used in the clinical diagnosis of degree of stenosis in the renal artery. In this study the effect of fat layers on maximum velocity estimations was determined using both a Doppler string and flow phantom. Using an ATL HDI 3000 with two broadband transducers (C4-2 and L12-5), the maximum velocity was estimated for a range of velocities with and without the presence of a fat layer. The results indicate that the introduction of a fat layer has a significant effect on the overestimation of the maximum velocity when the string phantom is used. However, in …

The Development Of A Quantum Dot Solar Concentrator, Brenda Rowan

Doctoral

The aim of this study was to investigate the feasibility of Quantum Dot Solar Concentrators (QDSCs). Quantum Dots offer the advantages of having broad absorption specr4a, tunable emission and improved stability. A range of Cadmium Selenide/|Zince Sulphide Quantum Dots were characterized in solution and composite form using time-resolved and steady state spectroscopie techniques and the stability of the composite samples was investigated over a 6 month period. A number of matrix materials were compared and the most suitable type for fabrication of QDSCs were identified. Techniques for fabrication and characterization of QDSCs were developed and a range of different QDSC …

Temporal Factors To Evaluate Trustworthiness Of Virtual Identities, Luca Longo, Pierpaolo Dondio, Stephen Barrett

Conference papers

In this paper we investigate how temporal factors (i.e. factors computed by considering only the time-distribution of interactions) can be used as an evidence of an entity’s trustworthiness. While reputation and direct experience are the two most widely used sources of trust in applications, we believe that new sources of evidence and new applications should be investigated [1]. Moreover, while these two classical techniques are based on evaluating the outcomes of interactions (direct or indirect), temporal factors are based on quantitative analysis, representing an alternative way of assessing trust. Our presumption is that, even with this limited information, temporal factors …

Proceedings Of The 18th Irish Conference On Artificial Intelligence And Cognitive Science, Sarah Jane Delany, Michael Madden

Books/Book Chapters

These proceedings contain the papers that were accepted for publication at AICS-2007, the 18th Annual Conference on Artificial Intelligence and Cognitive Science, which was held in the Technological University Dublin; Dublin, Ireland; on the 29th to the 31st August 2007. AICS is the annual conference of the Artificial Intelligence Association of Ireland (AIAI).

Enhancing Forensic Science Context-Based Laboratory Activities For Undergraduate Chemistry Students, Sarah Cresswell, John Fox, Claire M. Mcdonnell, Christine O'Connor, Cora O'Donnell, Michael K. Seery

Conference Papers

This paper discusses the development of student centred context-based practical activities for use in third level Forensic Science/ Chemical Analysis courses.

Task-Based Mood Induction Procedures For The Elicitation Of Natural Emotional Responses., Brian Vaughan, Charlie Cullen, Spyros Kousidis, Yi Wang

Other resources

This paper details experimental procedures designed to elicit real emotional responses from participants within a controlled acoustic environment. The experiments use Mood Induction Procedures (MIP’s), specifically MIP 4, to implement a co-operative task using two participants. These cooperative tasks are designed to engender emotional responses of activation and evaluation from the participants who are situated in separate isolation booths, thus reducing unwanted noise in the signal, preventing the participants from being distracted and ensuring a cleanly recorded audio signal. The audio is recorded at a professional level of quality (24bit/192Khz). The emotional dimensions of each audio recording will be evaluated …

Effects Of Htert On Genomic Instability Caused By Either Metals Or Radiation Or Combined Exposure, Antonino Glaviano

Doctoral

There is currently a great interest in delayed chromosomal damage and other damaging effects of low-dose exposure to a variety of agents, which appear collectively to act through induction of stress-response pathways related to oxidative stress (and aging). These agents have been studied mostly in the radiation field but evidence is accumulating that chemicals, especially heavy metals, can also act in the same manner. Therefore, this work investigated the effects of metals and/or radiation in human fibroblasts in vitro. Humans are exposed to metals, including chromium (CR) VI) and vanadium (V) (V) from the environment, industry and surgical implants. Thus …

An Investigation Of Introductory Physics Students’ Approaches To Problem Solving, Laura Walsh, Robert Howard, Brian Bowe

Articles

This paper outlines ongoing research investigating students’ approaches to quantitative and qualitative problem solving in physics. This is an empirical study, which was conducted using a phenomenographic approach to analyse and interpret data from individual semi-structured interviews with students from introductory physics courses. The result of the study thus far is a preliminary set of hierarchical categories that describe the students’ problem-solving approaches when faced with various physics problems. The findings from the research presented here indicate that many introductory students in higher education do not approach problem solving in a strategic manner and many do not try to link …

Metallopharmaceuticals As Photoactivatable Anticancer Drugs, Samar Moqadasi, Christine O'Connor, Denis O'Shea, Michael Devereux

Conference Papers

Target-based research (treating infected site only), directed towards the design and mechanism of action of metal-based anticancer complexes is expanding rapidly due to the selectivity and activity of such novel therapeutics. The photo activation of Ruthenium (II) complexes as therapeutic drugs has recently escalated as the complexes are suitable for photoactivation due to their well published photochemical and photophysical properties which in turn is the basis of photodynamic approaches to therapy.1-5 The aim of this study is to synthesise a series of metallo-complexes of which will be tested on tumour and non-tumour cell lines in the Radiation & Environmental Science …

Metallo-Cyclodextrin Complexes For The Separation Of Chiral Materials, Synthesis And Characterisation, Ciaran Francis Potter

Doctoral

The processes of separation and detection of chiral compounds are extremely important in the pharmaceutical industry. This study aims to investigate a safe and variable methods for the separation of the two enantiomers of the drug DOPA (Dihydroxyphenylalanine). L-DOPA is the most effective drug at present used to combat Parkinson’s disease while D-DOPA is inactive, thus for drug efficacy only the single biologically active enantiomer should be present in the formulation. In this work, cyclodextrins (CDS) were utilised fro their ability to act as a host for guest species, acting in the role as both a first and second sphere …

An Open Source Approach To Wireless Positioning Techniques, Seamus Rooney, Keith Gardiner, James Carswell

Conference papers

There are several problems encountered when trying to determine the location of a mobile phone, including weather you are in an urban or rural environment. Also, it is well known that different positioning technologies can work better than others depending on the environment they are in. For example, GPS works well in rural areas but not as well in urban areas, GSM positioning accuracy can be acceptable in urban areas with the right triangulation technology, but is less accurate in rural areas. Positioning with other technologies such as WiFi, Bluetooth, and Semacode all have their own advantages and disadvantages also, …

Continuous Improvement In E-Learning: Investigating The Effect And Impact Of Our Webct Chemistry Support Initiative (Csi) And Implications For Further Enhancement Of The Virtual Learning Environments (Vles) Developed, Christine O'Connor, Claire M. Mcdonnell, Michael K. Seery

Conference Papers

A Virtual Learning Environment (VLE) was developed using WebCT software and was piloted in 2004 in the School of Chemical and Pharmaceutical Sciences in DIT by the authors. This was one of a number of measures introduced with the aim of supporting and retaining first year undergraduates on the Science ordinary degree programme and was designed as a Chemistry Support Initiative (CSI) for first year Chemistry learning and teaching (O’Connor, 2005). This work was supported through funding from the DIT Learning and Teaching Centre which allowed a summer research assistant to be taken on. Since the launch of the first …

An Open Approach To Contextualising Heterogeneous Cultural Heritage Datasets, John Mcauley, James Carswell

Conference papers

This paper describes a semantic museum application, which aims to present a holistic impression of the Etruscan civilisation. Through the use of a distributed computing paradigm and the CIDOC CRM ontology, the system presents a unified view of a fragmented heritage, while supporting browse and search at a semantic level. Within the cultural heritage world, however, much value is placed on ‘context’, both in describing and presenting heritage artefacts. From this perspective, a platform built upon the distributed search paradigm, although useful in many respects, does not convey how an artefact sits within a broader setting. Narrative concepts are proposed …

Urban Location Based Services Using Mobile Clients: The Icing Approach, Eoin Kilfeather, James Carswell, Keith Gardiner, Seamus Rooney

Conference papers

The ICING project is conducting research into eGovernment and Location Based Services and also into two-way interaction with the physical environment. The research focuses on the areas of embedded intelligence, tighter integration of operator platforms and city infrastructure to enable novel services, empowerment of citizens to evolve systems of interaction with the city via social software, input from citizens and sensors for management systems and decision modelling, and a combination of city systems and multi-modal, multi-device communications to provide enhanced services. The technology platforms are gathering indicators from the City, processing the information, proposing actions to be taken with human …

A Three‐Dimensional Numerical Method For Modelling Weakly Ionized Plasmas, Stephen O'Sullivan, Turlough Downes

Articles

Astrophysical fluids under the influence of magnetic fields are often subjected to single- or two-fluid approximations. In the case of weakly ionized plasmas, however, this can be inappropriate due to distinct responses from the multiple constituent species to both collisional and non-collisional forces. As a result, in dense molecular clouds and protostellar accretion discs, for instance, the conductivity of the plasma may be highly anisotropic leading to phenomena such as Hall and ambipolar diffusion strongly influencing the dynamics.

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 …

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide Using An Isophthalate Precursor, Grainne Duffy, Declan Mccormack, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate precursor. In contrast to those processed from an oxalate precursor, this material exhibits three-dimensional, non-directional aggregation behaviour.

Such non-directional aggregation of uniaxial crystallites may allow for the production of structures with a higher proportion of catalytically active surfaces than can be prepared through conventional sol–gel methods. XRD,

FTIR, TEM and SEM were used to characterize the synthesized materials.

Zinc oxide particles synthesized by using isophthalic acid (C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously reported materials prepared through chelation with oxalic acid (H2C2O2・2H2O).

Growth Substrate Induced Functional Changes Elucidated By Ftir And Raman Spectroscopy In In-Vitro Cultured Human Keratinocytes., Aidan Meade, Fiona Lyng, Peter Knief, Hugh Byrne

Articles

Non-invasive measurements of cellular function in in-vitro cultured cell lines using vibrational spectroscopy require the use of spectroscopic substrates such as quartz, ZnSe and MirrIR etc. These substrates are generally dissimilar to the original in-vivo extracellular environment of a given cell line and are often tolerated poorly by cultured cell lines resulting in morphological and functional changes in the cell. The present study demonstrates various correlations between vibrational spectroscopic analyses and biochemical analyses in the evaluation of the interaction of a normal human epithelial keratinocyte cell line (HaCaT) with MirrIR and quartz substrates coated with fibronectin, laminin and gelatin. The …

A Systematic Study Of The Effects Of Naphthalene And Anthracene Substitution On The Properties Of Ppv Derivative Conjugated Systems, Patrick Lynch, Luke O'Neill, David Bradley, Hugh Byrne, Mary Mcnamara

Articles

The systematic synthesis of poly(phenylvinylene) (PPV) derivatives by the Wittig-Horner reaction is reported. The phenyl units of the PPV structure are methodically substituted by naphthyl and anthryl units to form a homologous series of structures. The 2,6 attachment of the vinylene linkage on the anthryl ring provides novel structures that have not been reported before due to their synthetic inaccessibility. The introduction of naphthyl units results in a hypsochromatic shift in the absorption and emission spectra, while the introduction of anthryl units leads to a bathochromatic shift relative to the naphthalene structures. The observed structural variation of the spectroscopic properties …

Spectroscopic Characterisation Of Novel Polycyclic Aromatic Polymers, Luke O'Neill, Patrick Lynch, Mary Mcnamara, Hugh Byrne

Articles

A series of novel polyphenylenevinylene (PPV) derivative polymers were studied by absorption and photoluminescence spectroscopies. The effect of the sequential introduction of polycyclic aromatic ring substituents into the delocalized backbone was examined with relation to hypsochromatic and bathochromatic shifting. While the replacement of the phenyl units by naphthyl units results in a substantial hypsochromic shift of both the absorption and emission spectra, their subsequent substitution by anthryl units results in a bathochromic shift. The system is modeled according to, and is found to be consistent with, a previous study of donor-acceptor polyenes of varying length. The electronic structure of the …

Vibrational Characterisation And Fluorescence Optimisation Of Polycyclic Polymers, Luke O'Neill, Patrick Lynch, Mary Mcnamara, Hugh Byrne

Articles

A systematic series of polycyclic novel polymers was studied by Raman spectroscopy. The effect of the sequential introduction of polycyclic aromatic ring substituents into the delocalized backbone was examined in relation to the variation of the relative ring breathing and stretching as well as the vinyl stretch frequencies. Replacement of the phenyl units by higher order acene moieties such as naphthyl and anthryl results in a shift of the characteristic stretching frequencies, and analysis of the vinyl stretch leads to the confirmation that higher order acene substitution into the delocalized backbone substantially weakens the vinyl bond. Semiquantitative integrated Raman analysis …

Reissner–Nordstrom¨ Expansion, Emil Prodanov, Rossen Ivanov, V.G. Gueorguiev

Conference papers

We propose a classical mechanism for the cosmic expansion during the radiation-dominated era, assuming the Universe as a two-component gas. The first component is the ultra-relativistic “standard” fraction described by an equation of state of an ideal quantum gas of massless particles. The second component consist of superheavy charged particles and their interaction with the “standard” fraction drives the expansion. This interaction is described by the Reissner–Nordstr¨om metric purely geometrically — the superheavy charged particles are modeled as zero-dimensional naked singularities which exhibit gravitational repulsion. The radius of a repulsive sphere, surrounding a naked singularity of charge Q, is inversely …

Modelling Of Re-Absorption Losses In Quantum Dot Solar Concentrators, Manus Kennedy

Conference Papers

A Monte-Carlo ray-trace model has been developed which allows the calculation of the optical efficiency (ηopt) and concentration ratio (CR) values of a Quantum Dot Solar Concentrator (QDSC). In this paper, ηopt values have been calculated using a range of material refractive indices, material attenuation coefficients, and quantum dot (QD) quantum efficiencies (QE). Spectral overlap leads to reabsorption of light in the device which leads to increased escape cone losses and QD QE losses. Results have been obtained for ideal QD spectra, where there is 0% overlap between QD emission and absorption spectra (and hence no re-absorption), and for real …