Physics Commons^™

Raman Spectroscopic Analysis Of Oral Squamous Cell Carcinoma And Oral Dysplasia In The High-Wavenumber Region, Hugh Byrne, Luis Felipe Carvalho, Fiona Lyng, Franck Bonnier

Articles

Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with excellent spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400–1,800 cm^-1) has been shown to be very promising for optical biopsy purposes. However, limitations to discrimination of dysplastic and inflammatory processes based on the fingerprint region still persist. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber …

Raman Spectroscopy For Screening And Diagnosis Of Cervical Cancer, Fiona Lyng, Damien Traynor, Ines Rm Ramos, Franck Bonnier, Hugh Byrne

Articles

Cervical cancer is the fourth most common cancer in women worldwide and mainly affects younger women. The mortality associated with cervical cancer can be reduced if this disease is detected at the pre-cancer stage. Current gold standard methods include cytopathology, HPV testing and histopathology but these methods are limited in terms of subjectivity, cost and time. There is an unmet clinical need for new methods to aid clinicians in the early detection of cervical pre-cancer. These methods should be objective, rapid and require minimal sample preparation. Raman spectroscopy is a vibrational spectroscopic technique by which incident radiation is used to …

Investigation Of Photopolymer-Based Holographic Optical Elements For Solar Applications, Hoda Akbari

Doctoral

The aim of this research was to explore the potential of photopolymer Holographic Optical Elements (HOE) for use in the collection of light from a moving source, such as the sun, and its direction into a fixed detector/convertor for application in solar concentrators. In order to increase the acceptance angle and the wavelength range of operation of the holographic device, low spatial frequency holographic recording was explored. The challenge was to record high diffraction efficiency HOEs at this spatial frequency, since it requires a material with relatively fast monomer diffusion. The acrylamide-based photopolymer developed at the Centre for Industrial and …

Determination Of Nanoparticle Localisation Within Subcellular Organelles In Vitro Using Raman Spectroscopy, Esen Efeoglu, Mark Keating, Jennifer Mcintyre, Alan Casey, Hugh Byrne

Articles

Ease of sample preparation, narrow spectral bandwidth and minimal influence from water are features of Raman spectroscopy which make it a powerful, label-free way to study a wide range of biological structures and phenomena. In this context, given the concerns over their toxicology arising from their increased production and use, evaluation of nanoparticle uptake and localisation in biological systems and determination of the mechanisms of subcellular interaction and trafficking can provide long-term solutions for nanotoxicology, and potential strategies for nanomedicine. In this study, Raman spectroscopy is explored to monitor the sequential trafficking of nanoparticles through subcellular organelles in-vitro and to …

Investigating The Role Of Shape On The Biological Impact Of Gold Nanoparticles In Vitro, Furong Tian, Hugh Byrne, Joao Conde, Tobias Stoeger, Martin Clift,, Alan Casey, Pablo Del Pino, Beatriz Pelaz, Barbara Rothen-Rutishauser,, Giovani Estrada, Jesús De La Fuente

Articles

Aim: To investigate the influence of gold nanoparticle (GNP) geometry on the biochemical response of Calu-3 epithelial cells.

Materials and Methods: Spherical, triangular and hexagonal GNPs were used. The GNP-cell interaction was assessed via atomic absorption spectroscopy (AAS) and transmission electron microscopy (TEM). The biochemical impact of GNPs was determined over 72hrs at [0.0001-1mg/mL].

Results: At 1mg/mL, hexagonal GNPs reduced Calu-3 viability below 60%, showed increased reactive oxygen species production and higher expression of pro-apoptotic markers. A cell mass burden of 1:2:12 as well as number of GNPs per cell (2:1:3) was observed for spherical:triangular:hexagonal GNPs.

Conclusion:

These findings do …

Determination Of The Polymerisation Rate Of A Low-Toxicity Diacetone Acrylamide-Based Holographic Photopolymer Using Raman Spectroscopy, Dervil Cody, Emilia Mihaylova, Luke O'Neill, Izabela Naydenova

Articles

The polymerisation rate of a low-toxicity Diacetone Acrylamide (DA)-based photopolymer has been measured for the first time using Raman spectroscopy. A value for the polymerisation rate of 0.020 s⁻¹ has been obtained for the DA photopolymer by modelling the polymerisation reaction dynamics as a stretched exponential or Kohlrausch decay function. This is significantly lower than the polymerisation rate of 0.100 s⁻¹ measured for the well known Acrylamide (AA)-based photopolymer composition. The effect of the additive glycerol on the polymerisation rate of the DA-based photopolymer has also been investigated. The inclusion of glycerol is observed to increase the rate …

Vibrational Spectroscopic Studies To Elucidate The Structure Of Water At Biological Interfaces, Bahar Bahrani, Luke O'Neill, Hugh Byrne

Articles

In biological systems, water takes up to 80% of the volume inside a cell. This water solubilizes the biological macromolecules such as the DNA, proteins and lipids. Recent advancements have shown that the water at the interface of a lipid membrane is structured, as five layers of structured water have been found at this solvent cage. Steady state Raman spectroscopy of water in lipids was performed in an attempt to elucidate the structure of water at the biological interface. Deuterium oxide (heavy water) was employed to hydrate lipid biomolecules. The heavier deuterium atom shifts the molecular vibrations and renders them …

Cellular Discrimination Using In Vitro Raman Micro Spectroscopy: The Role Of The Nucleolus, Hugh Byrne

Articles

Raman micro spectroscopy has attracted considerable attention over the last few years to explore its possible clinical applications as a non-invasive powerful label-free in vitro screening tool in cancer diagnosis and monitoring, subcellular analysis of biochemical processes, drug uptake, mode of action and mechanisms of interaction as well as toxicity of, for example, chemotherapeutic agents.

However, in order to evaluate accurately the potential of Raman micro spectroscopy for such applications it is essential to optimise measurement and data processing protocols associated with subcellular analysis. To this end, in vitro differentiation of cell lines is a basic proof of concept for …

Spectroscopic Characterization Of A Radio-Frequency Argon Plasma Jet Discharge In Ambient Air, Patrick Cullen, Vladimir Milosavljevic

Articles

This study includes a detailed experimental investigation of the spatial and temporal spectroscopic emission of an argon plasma jet discharge. The study is carried out in ambient air and quenching by inflowing air species is considered. The optical emission spectroscopy of neutral atomic spectral lines and molecular bands, over a range of plasma process parameters, is investigated. Wavelength-resolved argon optical emission profiles are used to monitor the electron energy distribution function and the density of argon metastable atoms. The experimental data indicates that the argon flow rate, in a confined open-air plasma discharge, limits the impact of molecular oxygen in …

Optimal Choice Of Sample Substrate And Laser Wavelength For Raman Spectroscopic Analysis Of Biological Specimen, Hugh Byrne, Laura Kerr, Bryan M. Hennelly

Articles

Raman spectroscopy is an optical technique based on the inelastic scattering of monochromatic light that can be used to identify

the biomolecular composition of biological cells and tissues. It can be used as both an aid for understanding the etiology

of disease and for accurate clinical diagnostics when combined with multivariate statistical algorithms. This method is nondestructive,potentially non-invasive and can be applied in vitro or in vivo directly or via a fiber optic probe. However, there exists a high degree of variability across experimental protocols, some of which result in large background signals that can often overpower the weak Raman …

The Prevalence Of Demodex Folliculorum On Eyelashes Of Symptomatic And Asymptomatic Normal Patients, Aoife Lloyd Mckernan, Veronica O'Dwyer, Orla Murphy

Other Resources

Purpose

To examine the prevalence of Demodex Folliculorum (DF) on the eyelashes of symptomatic and asymptomatic patients. DF is an eight legged ectoparasite present in humans. It is most commonly found on the face; cheeks, nose, chin and eyelashes. Ocular symptoms of DF infestation on the eyelashes include itching, dryness, surface irritation, burning, foreign body sensation, photophobia and reduced vision1

Method

Students and patients of the National Optometry Centre (NOC) (n=54), aged 19 – 78 years of age were assessed and sub-divided into 4 groups; Group (1) Control (n=12), Group (2) Signs, no symptoms (n = ?), Group (3) Symptoms, …

Available Work Rate Of A Reversible System Bounded By Constant Thermal Resistances Linked To Isothermal Reservoirs, Jim Mcgovern

Conference Papers

Exergy analysis is based on the concept of an idealized, all-enclosing reference environment that has infinite heat capacity and thermal conductivity, and is in equilibrium. The actual surroundings of a real plant such as a heat engine, a heat pump or a refrigerator may differ significantly from the ideal. First law performance parameters and second law rational efficiency are examined. The concepts of finite time thermodynamics are applied in an attempt to refine the concept of T0, the environmental reference temperature, thereby making exergy analysis more reflective of reality.

Raman Micro Spectroscopy For In Vitro Drug Screening: Subcellular Localisation And Interactions Of Doxorubicin, Zeineb Farhane, Franck Bonnier, Alan Casey, Hugh Byrne

Articles

Vibrational spectroscopy, including Raman spectroscopy, has been widely used over the last few years to explore potential biomedical applications. Indeed, Raman spectroscopy has been demonstrated to be a powerful non-invasive tool in cancer diagnosis and monitoring. In confocal microscopic mode, the technique is also a molecularly specific analytical tool with optical resolution which has potential applications in subcellular analysis of biochemical processes, and therefore as an in vitro screening tool of the efficacy and mode of action of, for example, chemotherapeutic agents.

In order to demonstrate and explore the potential in this field, established, model chemotherapeutic agents can be valuable. …

Multivariate Statistical Methodologies Applied In Biomedical Raman Spectroscopy: Assessing The Validity Of Partial Least Squares Regression Using Simulated Model Datasets., Mark Keating

Articles

Raman spectroscopy is fast becoming a valuable analytical tool in a number of biomedical scenarios, most notably disease diagnostics. Importantly, the technique has also shown increasing promise in the assessment of drug interactions on a cellular and subcellular level, particularly when coupled with multivariate statistical analysis. However, an important consideration, both with Raman spectroscopy and the associated statistical methodologies, is the accuracy of these techniques and more specifically the sensitivities which can be achieved and ultimately the limits of detection of the various methods. The purpose of this study is thus the construction of a model simulated data set with …

Optical Diagnostics – Spectropathology For The Next Generation, Malgorzata Baranska, Hugh Byrne

Articles

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Spectropathology For The Next Generation: Quo Vadis?, Hugh Byrne, Malgorzata Baranska, Gerwin J. Pupples, Nick Stone, Bayden Wood, Kathleen M. Gough, Peter Lasch, Phil Heraud, Josep Sulé-Suso, Ganesh Sockalingum

Articles

Although the potential of vibrational spectroscopy for biomedical applications has been well demonstrated, translation into clinical practice has been relatively slow. This Editorial assesses the challenges facing the field and the potential way forward. While many technological challenges have been addressed to date, considerable effort is still required to gain acceptance of the techniques among the medical community, standardise protocols, extend to a clinically relevant scale, and ultimately assess the health economics underlying clinical deployment. National and international research networks can contribute much to technology development and standardisation. Ultimately, large-scale funding is required to engage in clinical trials and instrument …

Vibrational Microspectroscopy For Cancer Screening, Fiona Lyng, Ines Ramos, Ola Ibrahim, Hugh Byrne

Articles

Vibrational spectroscopy analyses vibrations within a molecule and can be used to characterise a molecular structure. Raman spectroscopy is one of the vibrational spectroscopic techniques, in which incident radiation is used to induce vibrations in the molecules of a sample, and the scattered radiation may be used to characterise the sample in a rapid and non-destructive manner. Infrared (IR) spectroscopy is a complementary vibrational spectroscopic technique based on the absorption of IR radiation by the sample. Molecules absorb specific frequencies of the incident light which are characteristic of their structure. IR and Raman spectroscopy are sensitive to subtle biochemical changes …

Multivariate Statistical Methodologies Applied In Biomedical Raman Spectroscopy: Assessing The Validity Of Partial Least Squares Regression Using Simulated Model Datasets, Mark E. Keating, Haq Nawaz, Franck Bonnier, Hugh Byrne

Articles

Raman spectroscopy is fast becoming a valuable analytical tool in a number of biomedical scenarios, most notably disease diagnostics. Importantly, the technique has also shown increasing promise in the assessment of drug interactions on a cellular and subcellular level, particularly when coupled with multivariate statistical analysis. However, an important consideration, both with Raman spectroscopy and the associated statistical methodologies, is the accuracy of these techniques and more specifically the sensitivities which can be achieved and ultimately the limits of detection of the various methods. The purpose of this study is thus the construction of a model simulated data set with …

The Effect Of Two Weeks And Twenty-Four Hours Soft Contact Lens Cessation Times On Corneal Refractive Surgery Outcomes, Aoife Lloyd Mckernan, Luisa Simo Mannion, Veronica O'Dwyer

Other Resources

Purpose

To investigate the influence of previous soft contact lens (SCL) wear on outcomes of corneal refractive surgery (CRS). SCL wear can reduce accuracy of pre-operative corneal measurements and outcomes of CRS. Short SCL cessation times prior to CRS may be insufficient for resolution of SCL-induced corneal changes. It was hypothesised that the visual and refractive CRS outcomes would be worse in a SCL group compared to a non-contact lens (NCL) group and worse in a SCL group who ceased SCL wear for 24 hours when compared to those who ceased SCL wear for two weeks prior to examination and …

Exploring Technology Enhanced Instruction And Assessment In The Advanced Physics Laboratory, Aidan Meade, Aaron Mac Raighne, Elizabeth Gregan, Izabela Naydenova, Francis Pedreschi

Teaching Fellowships

The development of a strategic, thoughtful and reflective approach to the undertaking of experimental work is key to the development of physicists and physical scientists. This project undertook to remodel senior physics laboratories to adapt to changing skillsets required in the workplace and to instil the graduate attributes necessary for flexible employment in physics and related disciplines. The objective of this project was to foster an enquiry-based model that has been shown both to help engage the students with their subject and develop habits of experimental approach appropriate to physical scientists. The project used e-assessment methods and electronic documentation of …

Vacuum Polarization On The Brane, Cormac Breen, Matthew Hewitt,, Elizabeth Winstanley, Adrian Ottewill

Articles

We compute the renormalized expectation value of the square of a massless, conformally coupled, quantum scalar field on the brane of a higher-dimensional black hole. Working in the AADD braneworld scenario, the extra dimensions are flat and we assume that the compactification radius is large compared with the size of the black hole. The four-dimensional on-brane metric corresponds to a slice through a higher-dimensional Schwarzschild-Tangherlini black hole geometry and depends on the number of bulk space-time dimensions. The quantum scalar field is in a thermal state at the Hawking temperature. An exact, closed-form expression is derived for the renormalized expectation …

Refraction In Mozambique: Evaluations Of Practice And Development Of Competency Frameworks For Eye Care Personnel, Kajal Shah

Doctoral

Purpose The development of competency- based education for optometrists and mid-level eye-care personnel has been identified as an important component in the elimination of avoidable blindness and vision impairment. The Mozambique Eye care Project (MEP) is a multi-institutional collaboration, which seeks to facilitate greater access to training in eye health professions, which will ultimately contribute to providing affordable and accessible eye care within the public health system in Mozambique. An important tenet of the MEP is to develop and enhance the refraction training of all existing (ophthalmic technicians) and new eye care personnel (four-year training of optometrists and eighteen-month training …

The Contribution Of Non-Thermal And Advanced Oxidation Technologies Towards Dissipation Of Pesticide Residues, N. Misra

Articles

Background

The use of pesticides has stabilised the food production to a great extent and their usage cannot be avoided anymore. Nevertheless, common food processing operations always allowed dissipating pesticide residues in foods to some extent. Within the food science community and the food processing sector, non-thermal food technologies are being researched and commercialised at a great pace over the past three decades.

Scope and Approach

In this review we provide a critical analysis of the literature pertinent to the fate of pesticide residues during non-thermal processing of solid and liquid foods. We also identify the opportunities for further development …

Hamiltonian Approach To Internal Wave-Current Interactions In A Two-Media Fluid With A Rigid Lid, Alan Compelli, Rossen Ivanov

Articles

We examine a two-media 2-dimensional fluid system consisting of a lower medium bounded underneath by a flatbed and an upper medium with a free surface with wind generated surface waves but considered bounded above by a lid by an assumption that surface waves have negligible amplitude. An internal wave driven by gravity which propagates in the positive x-direction acts as a free common interface between the media. The current is such that it is zero at the flatbed but a negative constant, due to an assumption that surface winds blow in the negative x-direction, at the lid. We are concerned …