Physics Commons^™

Raman Spectroscopic Analysis Of Human Serum Samples Of Convalescing Covid-19 Positive Patients, Hugh Byrne, Naomi Jackson, Jaythoon Hassan

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Rapid screening, detection and monitoring of viral infection is of critical importance, as exemplified by the rapid spread of SARS-CoV-2, leading to the worldwide pandemic of COVID-19. This is equally the case for the stages of patient convalescence as for the initial stages of infection, to understand the medium and long terms effects, as well as the efficacy of therapeutic interventions. Optical spectroscopic techniques potentially offer an alternative to currently employed techniques of screening for the presence, or the response to infection. In this study, the ability of Raman spectroscopy to distinguish between samples of the serum of convalescent COVID-19 …

Optical Characterisation Of Holographic Diffusers And Bangerter Foils For Treatment Of Amblyopia, Matthew Hellis, Suzanne Martin, Matthew Sheehan, Kevin Murphy

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Amblyopia is a significant issue for children worldwide, and current treatment methods have drawbacks that can hinder treatment effectiveness and/or patient experience. This study proposes a new treatment method using holographic diffusers while also comparing their optical characteristics to a current treatment method (Bangerter foils). Holographic diffusers were developed by optically patterning thin polymer layers on a micron scale. Two compositions of photopolymer (acrylamide and diacetone acrylamide based) are analysed herein. Characterisation shows that holographic diffusers of either composition can achieve a wide range of on-axis intensity reductions, allowing for precise and customisable treatment levels by altering recording exposure time …

Estimating The Analytical Performance Of Raman Spectroscopy For Quantification Of Active Ingredients In Human Stratum Corneum, Hichem Kichou, Emilie Munnier, Yuri Dancik, Kamilia Kemel, Hugh Byrne, Ali Tfayli, Dominique Bertrand, Martin Soucé, Igor Chourpa, Franck Bonnier

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Confocal Raman microscopy (CRM) has become a versatile technique that can be applied routinely to monitor skin penetration of active molecules. In the present study, CRM coupled to multivariate analysis (namely PLSR—partial least squares regression) is used for the quantitative measurement of an active ingredient (AI) applied to isolated (ex vivo) human stratum corneum (SC), using systematically varied doses of resorcinol, as model compound, and the performance is quantified according to key figures of merit defined by regulatory bodies (ICH, FDA, and EMA). A methodology is thus demonstrated to establish the limit of detection (LOD), precision, accuracy, sensitivity (SEN), and …

International Consensus On Lung Function Testing During Covid-19 Pandemic And Beyond, Aisling Mcgowan, Pierantonio Laveneziana, Sam Bayat, Nicole Beydon, P.W. Boros, Felip Burgos, Matjaž Fležar, Monika Franczuk, Maria-Alejandra Galarza, Adrian H. Kendrick, Enrico Lombardi, Jellien Makonga-Braaksma, Meredith C. Mccormack, Laurent Plantier, Sanja Stanojevic, Irene Steenbruggen, Bruce Thompson, Allan L. Coates, Jack Wanger, Donald W. Cockcroft, Bruce Culver, Karl Sylvester, Frans De Jongh

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Coronavirus disease 2019 (COVID-19) has negatively affected the delivery of respiratory diagnostic services across the world due to the potential risk of disease transmission during lung function testing. Community prevalence, reoccurrence of COVID-19 surges and the emergence of different variants of SARS-CoV-2 have impeded attempts to restore services. Finding consensus on how to deliver safe lung function services for both patients attending and for staff performing the tests are of paramount importance. This international statement presents the consensus opinion of 23 experts in the field of lung function and respiratory physiology balanced with evidence from the reviewed literature. It describes …

Normative Data On The Foveal Avascular Zone In A Young Healthy Irish Population Using Optical Coherence Tomography Angiography, Susan M. O'Shea, Veronica O'Dwyer, Grainne Scanlon

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Purpose: To establish normative data on the size, shape and vascular profile of the foveal avascular zone (FAZ) in a young, healthy, Irish population, using the Cirrus 5000 HD-OCT. Certain diseases may alter FAZ appearance. Normative databases provide normal baseline values for comparison, thus improving diagnostic ability.

Methods: One hundred and fifty-four subjects aged 18–35 years old were recruited. Superficial FAZ area, diameter, circularity, ganglion cell layer, central macular thickness (CMT), vascular perfusion and density were measured using the Cirrus 5000. Axial length was measured with the IOL Master and blood pressure was measured using the Omron sphygmomanometer. …

Raman Spectroscopic Characterisation Of Non Stimulated And Stimulated Human Whole Saliva, Genecy Calado, Isha Behl, Hugh Byrne, Fiona Lyng

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Human saliva is a unique biofluid which can reflect the physiopathological state of an individual. The wide spectrum of molecules present in saliva, compounded by the close association of salivary composition to serum metabolites, can provide valuable information for clinical diagnostic applications through highly sensitive vibrational spectroscopic techniques such as Raman spectroscopy. However, the nature of saliva, in terms of collection and patient-related characteristics, can be considered factors which may strongly affect the Raman spectral profile of salivary samples and disrupt the search for specific salivary biomarkers in the detection of diseases. The main objective of this study was to …

The Potential Of Raman Spectroscopy In The Diagnosis Of Dysplastic And Malignant Oral Lesions, Ola Ibrahim, M. Toner, Steven Flint, Hugh Byrne, Fiona Lyng

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Early diagnosis, treatment and/or surveillance of oral premalignant lesions are important in preventing progression to oral squamous cell carcinoma (OSCC). The current gold standard is through histopathological diagnosis, which is limited by inter and intra observer and sampling errors. The objective of this work was to use Raman spectroscopy to discriminate between benign, mild, moderate and severe dysplasia and OSCC in formalin fixed paraffin preserved (FFPP) tissues. The study included 72 different pathologies from which 17 were benign lesions, 20 mildly dysplastic, 20 moderately dysplastic, 10 severely dysplastic and 5 invasive OSCC. The glass substrate and paraffin wax background were …

Biomedical Applications Of Vibrational Spectroscopy: Oral Cancer Diagnostics, Hugh Byrne, Isha Behl, Genecy Calado, Ola Ibrahim, M. Toner, Sheila Galvin, Claire M. Healy, Steven Flint, Fiona Lyng

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Vibrational spectroscopy, based on either infrared absorption or Raman scattering, has attracted increasing attention for biomedical applications. Proof of concept explorations for diagnosis of oral potentially malignant disorders and cancer are reviewed, and recent advances critically appraised. Specific examples of applications of Raman microspectroscopy for analysis of histological, cytological and saliva samples are presented for illustrative purposes, and the future prospects, ultimately for routine, chairside in vivo screening are discussed.

Investigation Of The Chemical Composition Of Plasma-Treated Water By Midiplexc And Its Antimicrobial Effect On L. Monocytogenes And Pseudomonas Fluorescens Monospecies Suspension Cultures, Oliver Handorf, Harald Below, Uta Schnabel, Katharina Riedel

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Plasma -generated compounds conceived by microwave -induced plasma (MidiPLexc) were physicochemically investigated in their molecular compositions. Therefore, plasma -treated water (PTW) was generated by treatment with the MidiPLexc within a 1 l glass bottle for a pre -treatment time of 100 s, 300 s and 900 s. The PTW was further investigated in its composition of reactive oxygen/nitrogen species. For this purpose, the hydrogen peroxide (H2O2) concentration of the PTW was determined electrochemically using chronoamperometry, and the anionic components were determined using ion chromatography. As a result, H2O2 concentrations of up to 720 mg l−1 , nitrite concentrations of 1600 …

An Investigation Of The Detection Capability Of Pulsed Wave Duplex Doppler Of Low Grade Stenosis Using Ultrasound Contrast Agent Microbubbles – An In-Vitro Study, Jacinta Browne, Deirdre King, Andrew Fagan, Deepa Chari, Carmel Moran

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Objective: The objective of the study was to investigate whether clinically used ultrasonic contrast agents improved the accuracy of spectral Doppler ultrasound in the detection of low grade (< 50%) renal artery stenosis. Low grade stenoses in the renal artery are notoriously difficult to reliably detect using Doppler ultrasound due to difficulties such as overlying fat and bowel gas.

Methods: A range of anatomically-realistic renal artery phantoms with varying low degrees of stenosis (0, 30 and 50%) were constructed and peak velocity data was measured from within the pre-stenotic and mid-stenotic regions in each phantom, for both unenhanced and contrast-enhanced spectral Doppler data acquisitions. The effect of a 20mm overlying fat layer on the ultrasound beam distortion and phase aberration, and hence on the measured peak velocity data, was also …

Use Of Novel Anthropomorphic Breast Ultrasound Phantoms For Radiology Resident Education, Jacinta Browne, Chris Gu, Robert Fazzio, Andrew Fagan, Donald Tradup, Nicholas Hangiandreou

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Purpose: This study evaluated the training and assessment role of anthropomorphic breast ultrasound phantoms which simulated both the morphological and sonographic characteristics of breast tissue, including lesions, in a group of radiology residents at a large academic medical center. Methods: This was a prospective study involving 9 residents across all years (2^nd–4^th year) of a radiology residency program. Baseline assessments of all residents ability to detect and characterize lesions in P-I were carried out, followed by a two-hour teaching session on the same phantom. All residents underwent a post-training, final assessment on P-II to evaluate changes in …

Investigation Of The Assessment Of Low Degree (<50%) Renal Artery Stenosis Based On Velocity Flow Profile Analysis Using Doppler Ultrasound: An In-Vitro Study, Andrew Malone, Deepa Chari, Sean Cournane, Izabela Naydenova, Andrew Fagan, Jacinta Browne

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Purpose: Renal arterial stenosis can lead to disrupted renal function due to reduced blood flow to the kidneys and is largely thought to be caused by atherosclerosis. Current diagnostic strategies for renal arterial stenosis rely on detecting large degree stenoses (>50%). This study aimed to test the viability of using Doppler ultrasound to assess velocity profiles to detect the presence of low degree (<50%) stenoses.

Methods: A series of anatomically realistic renal artery flow phantoms were constructed exhibiting a range of low degree stenoses (symmetric and asymmetric). The behaviour of fluid flow in the phantoms was examined using Doppler ultrasound …

Exploring Subcellular Responses Of Prostate Cancer Cells To X-Ray Exposure By Raman Mapping, Maciej Roman, Agnieszka Panek, Hugh Byrne, Tomasz P Wrobel, Esen Efeoglu, Czeslawa Paluszkiewicz, Wojciech Maria Kwiatek

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Understanding the response of cancer cells to ionising radiation is a crucial step in modern radiotherapy. Raman microspectroscopy, together with Partial Least Squares Regression (PLSR) analysis has been shown to be a powerful tool for monitoring biochemical changes of irradiated cells on the subcellular level. However, to date, the majority of Raman studies have been performed using a single spectrum per cell, giving a limited view of the total biochemical response of the cell. In the current study, Raman mapping of the whole cell area was undertaken to ensure a more comprehensive understanding of the changes induced by X-ray radiation. …

Raman Spectral Analysis For Rapid Screening Of Dengue Infection, Tahir Mahmood, Haq Nawaz, A. Ditta, M.I. Majeed, M.A. Hanif, N. Rashid, H.N. Bhatti, H.F. Nargis, M. Saleem, Franck Bonnier, Hugh Byrne

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Infection with the dengue virus is currently clinically detected according to different biomarkers in human blood plasma, commonly measured by enzyme linked immunosorbent assays, including non-structural proteins (Ns1), immunoglobulin M (IgM) and immunoglobulin G (IgG). However, there is little or no mutual correlation between the biomarkers, as demonstrated in this study by a comparison of their levels in samples from 17 patients. As an alternative, the label free, rapid screening technique, Raman spectroscopy has been used for the characterisation/diagnosis of healthy and dengue infected human blood plasma samples. In dengue positive samples, changes in specific Raman spectral bands associated with …

Enabling Quantification Of Protein Concentration In Human Serum Biopsies Using Attenuated Total Reflectance – Fourier Transform Infrared (Atr-Ftir) Spectroscopy, Kate Spalding, Franck Bonnier, Clément Bruno, Hélène Blasco, Ruth E. Board, Isabelle Benz-De-Bretagne, Hugh Byrne, Holly J. Butler, Igor Chourpa, Pretheepan Radhakrishnan, Matthew J. Baker

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Changes in protein concentrations within human blood are used as an indicator for nutritional state, hydration and underlying illnesses. They are often measured at regular clinical appointments and the current analytical process can result in long waiting times for results and the need for return patient visits. Attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy has the ability to detect minor molecular differences, qualitatively and quantitatively, in biofluid samples, without extensive sample preparation. ATR-FTIR can return an analytical measurement almost instantaneously and therefore could be deemed as an ideal technique for monitoring molecular alterations in blood within the clinic. …

A Mathematical Analysis Of Drug Dissolution In The Usp Flow Through Apparatus, David Mcdonnell, Deirdre M. D'Arcy, Lawrence J. Crane, Brendan Redmond

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This paper applies boundary layer theory to the process of drug dissolution in the USP (United States Pharmacopeia) Flow Through Apparatus. The mass transfer rate from the vertical planar surface of a compact within the device is examined. The theoretical results obtained are then compared with those of experiment. The paper also examines the effect on the dissolution process caused by the interaction between natural and forced convection within the apparatus and the introduction of additional boundaries.

Broadband Acoustic Measurement Of The Agar-Based Tissue Mimicking Material – A Longitudinal Study, Adela Rabell-Montiel, Jacinta Browne, Stephen Pye, Tom Anderson, Carmel Moran

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Commercially available ultrasound quality assurance test phantoms rely upon the long-term acoustic stability of tissue-mimicking-materials (TMMs). The measurement of the acoustic properties can be technically challenging and it is important to ensure its stability. The standard technique is to film-wrap samples of TMM and to measure the acoustic properties in a water bath. In this study, a modified technique is proposed whereby the samples of TMM are measured in a preserving fluid that is intended to maintain their characteristics. The acoustic properties were evaluated using a broadband pulse-echo substitution technique over the frequency range of 4.5 – 50 MHz at …

Ultra-Filtration Of Human Serum For Improved Quantitative Analysis Of Low Molecular Weight Biomarkers Using Atr-Ir Spectroscopy, Franck Bonnier, Luis Felipe Cs. Carvalho, Matthew J. Baker, Hugh Byrne, Igor Chourpa

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Infrared spectroscopy is a reliable, rapid and cost effective characterisation technique, delivering a molecular finger print of the sample. It is expected that its sensitivity would enable detection of small chemical variations in biological samples associated with disease. ATR-IR is particularly suitable for liquid sample analysis and, although air drying is commonly performed before data collection, just a drop of human serum is enough for screening and early diagnosis. However, the dynamic range of constituent biochemical concentrations in the serum composition remains a limiting factor to the reliability of the technique. Using glucose as a model spike in human serum, …

Extraoral Maxillofacial Prosthesis Implant Retention Systems: A Critical Review., Hugh Byrne, Marina L. Pimentel

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Objectives: The purpose of this literature review is to provide information on the different available techniques for implant-supported prosthetic retention, which are bar-clip, o-ring or magnets. Through presenting the practitioner preferences reported in literature, although limited from strict comparison due to the heterogeneity of methodologies and studied individuals, this review aims to identify the choices for maxillofacial prosthesis implant retention systems, regarding patient comfort and good aesthetic outcome, as an aid to surgical and prosthetic planning for implant-supported extraoral maxillofacial prosthetics. With proper knowledge of each implant retention system, a practitioner can design a treatment plan which allows for a …

Retention Systems For Extraoral Maxillofacial Prosthetic Implants: A Critical Review, M.V. Cobein, N.P. Coto, O. Crivello Junior, J.B.D. Lemos, L.M. Vieira, M.L. Pimentel, Hugh Byrne, R.B. Dias

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We describe the techniques available for retention of implant-supported prostheses: bar-clips, O-rings, and magnets. We present reported preferences and, although this is limited by the heterogeneity of methods used and patients studied, we hope we have identified the best retention systems for maxillofacial prosthetic implants. If practitioners know the advantages and disadvantages of each system, they can choose the most natural and comfortable prosthesis. We searched the PubMed and Scopus databases, and restricted our search to papers published 2001–13. MeSH terms used were Maxillofacial prosthesis and Craniofacial prosthesis OR Craniofacial prostheses. We found a total of 2630 papers, and after …

Linking Atr-Ftir And Raman Features To Phenolic Extractability And Other Attributes In Grape Skin, Hugh Byrne, Abigain Rooney, Julio Nogales-Bueno, Jose Miguel Hernandez-Hierro, Francisco Jose Heredia

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The importance of wine phenolics on the sensory characteristic of red wines is well-known. Therefore, it is necessary to control the extractability of phenolic compounds from grape skins, which depends significantly on grape ripeness and hence, on cell wall degradation.

In the present study, attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman spectra of grape skin have been recorded. Then, these spectral matrices have been studied and the main spectral features have been linked to extractabilities of phenolic compounds (anthocyanins, flavanols and total phenols). Moreover, spectral differences between external and internal grape skin surfaces also have been studied.

It …

Determination Of Spectral Markers Of Cytotoxicity And Genotoxicity Using In Vitro Raman Microspectroscopy: Cellular Responses To Polyamidoamine Dendrimer Exposure, Esen Efeoglu, Alan Casey, Hugh Byrne

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Although consumer exposure to nanomaterials is ever increasing, with potential increased applications in areas such as drug and/or gene delivery, contrast agents and diagnosis, determination of cyto- and geno- toxic effect of nanomaterials on human health and the environment still remains challenging. Although many techniques have been established and adapted to determine the cytotoxicity and genotoxicity of nano-sized materials, these techniques remain limited by the number of assays required, total cost, use of labels and they struggle to explain the underlying interaction mechanisms. In this study, Raman microspectroscopy is employed as an in vitro label free high content screening technique …

Recent Advances In Optical Diagnosis Of Oral Cancers: Review And Future Perspectives, Ola Ibrahim, Hugh Byrne, Fiona Lyng, Surya Singh, Jopi Mikkonen, Arto Koistinen, Arja Kullaa

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Optical diagnosis techniques offer several advantages over traditional approaches, including objectivity, speed and cost, and these label-free, non-invasive methods have the potential to change the future work-flow of cancer management. The oral cavity is particularly accessible and thus such methods may serve as alternate/adjunct tools to traditional methods. Recently, in vivo human clinical studies have been initiated with a view to clinical translation of such technologies. A comprehensive review of optical methods in oral cancer diagnosis is presented. Following an introduction to the epidemiology and aetiological factors associated with oral cancers currently employed diagnostic methods and their limitations are presented. …

Screening For Peripheral Arterial Disease And Carotid Artery Disease In Patients With Abdominal Aortic Aneurysm, Cleona Gray, Patrick J. Goodman, Paul Cullen, Stephen Badger, Kevin O'Malley, Martin K. O'Donohoe, Ciarán O. Mcdonnell

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Screening for concomitant atherosclerotic disease is important in cardiovascular risk reduction. This study assessed the prevalence of carotid artery disease (CAD) and peripheral arterial disease (PAD) in patients with known abdominal aortic aneurysms (AAAs). All patients with AAA attending the vascular laboratory between the January 1, 2007, and December 31, 2009, were eligible for a carotid ultrasound and measurement of ankle brachial indices. A total of 389 (305 males) patients were identified on the AAA surveillance program with a mean (±standard deviation) age of 76 (±8) years. The mean age of the males was 75.4 (±7.8) years, and the mean …

Endovascular Aneurysm Repair Increases Aortic Arterial Stiffness When Compared To Open Repair Of Abdominal Aortic Aneurysms, Cleona Gray, Patrick J. Goodman, Stephen Badger, M. Kevin O'Malley, Martin K. O'Donohoe, Ciarán O. Mcdonnell

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Objectives: The initial survival advantage seen with endovascular aneurysm repair (EVAR) over open repair does not persist in the long term. Pulse wave velocity (PWV) is a measure of arterial stiffness, and increased PWV is an independent risk factor for increased cardiovascular morbidity and mortality. This prospective comparative pilot study examined the effect of implantation of an aortic graft on PWV in patients undergoing open or endovascular aortic aneurysm repair. Patients and Methods: Thirty-four patients (15 open and 19 EVAR) were recruited. Patient demographics were similar in both the groups. Pulse wave velocity was calculated for all patients …

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

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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. …

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

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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

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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

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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

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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 …