Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

PDF

Series

Raman spectroscopy

Discipline
Institution
Publication Year
Publication

Articles 1 - 30 of 46

Full-Text Articles in Physics

Raman Spectroscopic Analysis Of Human Serum Samples Of Convalescing Covid-19 Positive Patients, Hugh Byrne, Naomi Jackson, Jaythoon Hassan Dec 2023

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

Articles

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 …


Reconversion Of Parahydrogen Gas In Surfactant-Coated Glass Nmr Tubes, Robert V. Chimenti, James Daley, James Sack, Jennifer Necsutu, Nicholas Whiting Mar 2023

Reconversion Of Parahydrogen Gas In Surfactant-Coated Glass Nmr Tubes, Robert V. Chimenti, James Daley, James Sack, Jennifer Necsutu, Nicholas Whiting

Faculty Scholarship for the College of Science & Mathematics

The application of parahydrogen gas to enhance the magnetic resonance signals of a diversity of chemical species has increased substantially in the last decade. Parahydrogen is prepared by lowering the temperature of hydrogen gas in the presence of a catalyst; this enriches the para spin isomer beyond its normal abundance of 25% at thermal equilibrium. Indeed, parahydrogen fractions that approach unity can be attained at sufficiently low temperatures. Once enriched, the gas will revert to its normal isomeric ratio over the course of hours or days, depending on the surface chemistry of the storage container. Although parahydrogen enjoys long lifetimes …


Contributions Of Vibrational Spectroscopy To Virology: A Review, Iqra Chaudhary, Naomi Jackson, Denise Denning, Luke O'Neill, Hugh Byrne May 2022

Contributions Of Vibrational Spectroscopy To Virology: A Review, Iqra Chaudhary, Naomi Jackson, Denise Denning, Luke O'Neill, Hugh Byrne

Articles

Vibrational spectroscopic techniques, both infrared absorption and Raman scattering, are high precision, label free analytical techniques which have found applications in fields as diverse as analytical chemistry, pharmacology, forensics and archeometrics and, in recent times, have attracted increasing attention for biomedical applications. As analytical techniques, they have been applied to the characterisation of viruses as early as the 1970s, and, in the context of the coronavirus disease 2019 (COVID-19) pandemic, have been explored in response to the World Health Organisation as novel methodologies to aid in the global efforts to implement and improve rapid screening of viral infection. This review …


Biochemical Impact Of Solar Radiation Exposure On Human Keratinocytes Monitored By Raman Spectroscopy; Effects Of Cell Culture Environment, Ulises Lopez Gonzalez, Alan Casey, Hugh Byrne Jul 2021

Biochemical Impact Of Solar Radiation Exposure On Human Keratinocytes Monitored By Raman Spectroscopy; Effects Of Cell Culture Environment, Ulises Lopez Gonzalez, Alan Casey, Hugh Byrne

Articles

Understanding and amelioration of the effects of solar radiation exposure are critical in preventing the occurrence of skin cancer. Towards this end, many studies have been conducted in 2D cell culture models under simplified and unrealistic conditions. 3D culture models better capture the complexity of in vivo physiology, although the effects of the 3D extracellular matrix have not been well studied. Monitoring the instantaneous and resultant cellular responses to exposure, and the influence of the 3D environment, could provide an enhanced understanding of the fundamental processes of photocarcinogenesis. This work presents an analysis of the biochemical impacts of simulated solar …


Raman Spectroscopic Characterisation Of Non Stimulated And Stimulated Human Whole Saliva, Genecy Calado, Isha Behl, Hugh Byrne, Fiona Lyng May 2021

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

Articles

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 …


Development Of 3d In Vitro Tissue Models For The Analysis Of Solar Radiation Damage Of Skin, Ulises Lopez Gonzalez Mar 2021

Development Of 3d In Vitro Tissue Models For The Analysis Of Solar Radiation Damage Of Skin, Ulises Lopez Gonzalez

Doctoral

The aim of this work was to investigate changes to the molecular composition and conformation of HaCaT cells as a result of simulated solar radiation in a 3D in vitro skin model by Raman spectroscopy. The process to achieve this goal was performed in three main stages: (1) optimisation of the working concentration and volume of two 3D membranes, used as a structural support in the skin model; (2) the construction of the 3D in vitro skin model and; (3) the investigation of the dose-dependent effects of solar radiation on HaCaT cells in the skin model in comparison with the …


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 Feb 2021

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

Articles

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.


Advanced Raman Spectroscopy Detection Of Oxidative Damage In Nucleic Acid Bases: Probing Chemical Changes And Intermolecular Interactions In Guanosine At Ultralow Concentration, Francesca Ripanti, Claudia Fasolato, Flavia Mazzarda, Simonetta Palleschi, Marina Ceccarini, Chunchun Li, Margherita Bignami, Enrico Bodo, Steven E.J. Bell, Filomena Mazzei, Paolo Postorino Jan 2021

Advanced Raman Spectroscopy Detection Of Oxidative Damage In Nucleic Acid Bases: Probing Chemical Changes And Intermolecular Interactions In Guanosine At Ultralow Concentration, Francesca Ripanti, Claudia Fasolato, Flavia Mazzarda, Simonetta Palleschi, Marina Ceccarini, Chunchun Li, Margherita Bignami, Enrico Bodo, Steven E.J. Bell, Filomena Mazzei, Paolo Postorino

Bioelectrics Publications

DNA/RNA synthesis precursors are especially vulnerable to damage induced by reactive oxygen species occurring following oxidative stress. Guanosine triphosphates are the prevalent oxidized nucleotides, which can be misincorporated during replication, leading to mutations and cell death. Here, we present a novel method based on micro-Raman spectroscopy, combined with ab initio calculations, for the identification, detection, and quantification of oxidized nucleotides at low concentration. We also show that the Raman signature in the terahertz spectral range (<100 >cm(-1)) contains information on the intermolecular assembly of guanine in tetrads, which allows us to further boost the oxidative damage detection limit. Eventually, we …


Toward Non-Invasive Measurement Of Atmospheric Temperature Using Vibro-Rotational Raman Spectra Of Diatomic Gases, Tyler Capek, Jacek Borysow, Claudio Mazzoleni, Massimo Moraldi Dec 2020

Toward Non-Invasive Measurement Of Atmospheric Temperature Using Vibro-Rotational Raman Spectra Of Diatomic Gases, Tyler Capek, Jacek Borysow, Claudio Mazzoleni, Massimo Moraldi

Michigan Tech Publications

We demonstrate precise determination of atmospheric temperature using vibro-rotational Raman (VRR) spectra of molecular nitrogen and oxygen in the range of 292–293 K. We used a continuous wave fiber laser operating at 10 W near 532 nm as an excitation source in conjunction with a multi-pass cell. First, we show that the approximation that nitrogen and oxygen molecules behave like rigid rotors leads to erroneous derivations of temperature values from VRR spectra. Then, we account for molecular non-rigidity and compare four different methods for the determination of air temperature. Each method requires no temperature calibration. The first method involves fitting …


Processing And Characterization Of Spin-Coated As2s3 Films For Direct Laser Writing, Mia Truman May 2020

Processing And Characterization Of Spin-Coated As2s3 Films For Direct Laser Writing, Mia Truman

Physics and Astronomy Presentations

Diffraction gratings, waveguides, and resonators are components of photonic devices that can be fabricated using chalcogenide glasses. These chalcogenide components can be made through a process of direct laser writing and etching to reveal targeted structures on the surface of the films. Thermal deposition in combination with targeted laser irradiation has been used on As2S3 films with excellent results, but spin-coating as a method of deposition has been less explored. Spin-Coating is a relatively inexpensive procedure where a bulk glass is dissolved into a solution using amines and “spun” onto a substrate. This is a low-cost alternative …


Can Ethanol Affect The Cell Structure - A Dynamic Molecular And Raman Spectroscopy Study, Luis Felipe Carvalho, Laurita Dos Santos, Kate O'Callaghan, Franck Bonnier, Steven Flint, Fiona Lyng, Hugh Byrne Feb 2020

Can Ethanol Affect The Cell Structure - A Dynamic Molecular And Raman Spectroscopy Study, Luis Felipe Carvalho, Laurita Dos Santos, Kate O'Callaghan, Franck Bonnier, Steven Flint, Fiona Lyng, Hugh Byrne

Articles

The role that tobacco consumption plays in the etiology of oral cancer carcinogenesis, and of alcohol consumption acting as a co-factor, have been well established. However, in recent years, the contribution of alcohol consumption alone to oral cancer has been proposed. In fact, a high percentage of patients who develop oral cancer have both habits (tobacco and alcohol consumption), and other small patient groups only consume alcohol or do not have any other identifiable bad habits. In the present study, we demonstrate for the first time, using a combination of dynamic molecular modelling and Raman spectroscopy, that ethanol has a …


Quantitative Analysis Of Human Blood Serum Using Vibrational Spectroscopy., Hugh Byrne, Franck Bonnier, Jennifer Mcintyre, Drishya Rajan Parachalil Jan 2020

Quantitative Analysis Of Human Blood Serum Using Vibrational Spectroscopy., Hugh Byrne, Franck Bonnier, Jennifer Mcintyre, Drishya Rajan Parachalil

Articles

Analysis of bodily fluids using vibrational spectroscopy has attracted increasing attention in recent years. In particular, infrared spectroscopic screening of blood products, particularly blood serum, for disease diagnostics has been advanced considerably, attracting commercial interests. However, analyses requiring quantification of endogenous constituents or exogenous agents in blood are less well advanced. Recent advances towards this end are reviewed, focussing on infrared and Raman spectroscopic analyses of human blood serum. The importance of spectroscopic analysis in the native aqueous environment is highlighted, and the relative merits of infrared absorption versus Raman spectroscopy are considered, in this context. It is argued that …


Multivariate Statistical Methodologies Used In In-Vitro Raman Spectroscopy: Simulations And Applications For Drug And Nanoparticle Interactions, Mark Edward Keating Jan 2019

Multivariate Statistical Methodologies Used In In-Vitro Raman Spectroscopy: Simulations And Applications For Drug And Nanoparticle Interactions, Mark Edward Keating

Doctoral

Raman spectroscopy is a growing technology in the fields of in-vitro drug and nanoparticle screening. The label free capability provided by vibrational spectroscopy, as well as the ability of the technique to probe the chemical nature of samples, makes it a good candidate for use in these fields. Crucial to the progress of these methods is the development and validation of robust and accurate multivariate statistical analysis protocols. In this thesis, both established and novel methods are examined using both real and simulated datasets. In particular, simulated datasets are used to validate and assess the accuracy of these methods in …


Raman Spectroscopy Detects Biochemical Changes Due To Different Cell Culture Environments In Live Cells In Vitro, Mahmoud Gargotti, Esen Efeoglu, Hugh Byrne, Alan Casey Oct 2018

Raman Spectroscopy Detects Biochemical Changes Due To Different Cell Culture Environments In Live Cells In Vitro, Mahmoud Gargotti, Esen Efeoglu, Hugh Byrne, Alan Casey

Articles

The in vitro cell culture environment can impact on cell biochemistry and cell cycle. The manifestation of such substrate-induced changes in cell cycle in the Raman microspectroscopic profiles of cell cultures is investigated at the level of nucleolus, nucleus and cytoplasm. HeLa immortalised human cervical cells and HaCaT dermal cells were cultured on three different substrates, conventional polystyrene cell culture dishes, CaF2 slides as a commonly used Raman substrate, and glass slides coated with Collagen Rat Tail, as a mimic of the extra cellular matrix (ECM) environment. A cell cycle study, based on percentage DNA content, as determined using Propidium …


Study Of Phenolic Extractability In Grape Seeds By Means Of Atr-Ftir And Raman Spectroscopy, Julio Nogales-Bueno, Berta Baca-Bocanegra, Abigail Rooney, José Miguel Hernández-Hierro, Hugh Byrne, Francisco José Heredia Jan 2017

Study Of Phenolic Extractability In Grape Seeds By Means Of Atr-Ftir And Raman Spectroscopy, Julio Nogales-Bueno, Berta Baca-Bocanegra, Abigail Rooney, José Miguel Hernández-Hierro, Hugh Byrne, Francisco José Heredia

Articles

Near infrared hyperspectral imaging has been applied to grape seeds in order to select a representative subset of samples according to their spectral features in the 900-1700nm range. Afterwards, selected grape seeds have been classified according to their total phenol and flavanol extractabilities. In this way, samples were sorted in three different groups identified as low, medium and high extractability levels. In order to establish the chemical structures which can be responsible for the different extractabilities, vibrational spectroscopy has been applied to the non-extracted material after seed extractions. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman spectra of non-extracted …


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 Jan 2017

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

Articles

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 …


In Vitro Monitoring Of Time And Dose Dependent Cytotoxicity Of Aminated Nanoparticles Using Raman Spectroscopy, Esen Efeoglu, Alan Casey, Hugh Byrne Jul 2016

In Vitro Monitoring Of Time And Dose Dependent Cytotoxicity Of Aminated Nanoparticles Using Raman Spectroscopy, Esen Efeoglu, Alan Casey, Hugh Byrne

Articles

No abstract provided.


Spectroscopic Studies Of Anthracyclines: Structural Characterization And In Vitro Tracking, Zeineb Farhane, Hugh Byrne, Malgorzata Baranska Jul 2016

Spectroscopic Studies Of Anthracyclines: Structural Characterization And In Vitro Tracking, Zeineb Farhane, Hugh Byrne, Malgorzata Baranska

Articles

A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488 nm and 785 nm …


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 Mar 2016

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

Articles

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. …


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 Dec 2015

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 Nov 2015

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 …


Determination Of Nanoparticle Localisation Within Subcellular Organelles In Vitro Using Raman Spectroscopy, Esen Efeoglu, Mark Keating, Jennifer Mcintyre, Alan Casey, Hugh Byrne Nov 2015

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 …


Vibrational Spectroscopic Studies To Elucidate The Structure Of Water At Biological Interfaces, Bahar Bahrani, Luke O'Neill, Hugh Byrne Oct 2015

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 …


Raman Micro Spectroscopy For In Vitro Drug Screening: Subcellular Localisation And Interactions Of Doxorubicin, Zeineb Farhane, Franck Bonnier, Alan Casey, Hugh Byrne May 2015

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. …


Recent Advancement On The Optical Properties Of Two-Dimensional Molybdenum Disulfide (Mos2) Thin Films, Mingxiao Ye, Dustin Winslow, Dongyan Zhang, Ravindra Pandey, Yoke Khin Yap Mar 2015

Recent Advancement On The Optical Properties Of Two-Dimensional Molybdenum Disulfide (Mos2) Thin Films, Mingxiao Ye, Dustin Winslow, Dongyan Zhang, Ravindra Pandey, Yoke Khin Yap

Department of Physics Publications

The emergence of two-dimensional (2D) materials has led to tremendous interest in the study of graphene and a series of mono- and few-layered transition metal dichalcogenides (TMDCs). Among these TMDCs, the study of molybdenum disulfide (MoS2) has gained increasing attention due to its promising optical, electronic, and optoelectronic properties. Of particular interest is the indirect to direct band-gap transition from bulk and few-layered structures to mono-layered MoS2, respectively. In this review, the study of these properties is summarized. The use of Raman and Photoluminescence (PL) spectroscopy of MoS2 has become a reliable technique for differentiating …


Improved Protocols For Vibrational Spectroscopic Analysis Of Body Fluids, Franck Bonnier, François Petitjean, Matthew Baker, Hugh Byrne Mar 2014

Improved Protocols For Vibrational Spectroscopic Analysis Of Body Fluids, Franck Bonnier, François Petitjean, Matthew Baker, Hugh Byrne

Articles

The applications of vibrational spectroscopy to the examination of human blood serum are explored. Although FTIR spectra can be recorded in aqueous solutions at (gelatin) concentrations as low as 100mg/L, the high-wavenumber region remains obscured by water absorption. Using Raman spectroscopy, high quality spectra of gelatine solutions as low as 10mg/L can be achieved, also covering the high-wavenumber regions. In human serum, spectral profiles are weak and partially obscured by water features. Dried deposits are shown to be physically and chemically inhomogeneous resulting in reduced measurement reproducibility. Concentration of the serum using commercially available centrifugal filter devices results in an …


Sensitive And Specific Discrimination Of Pathogenic And Nonpathogenic Escherichia Coli Using Raman Spectroscopy - A Comparison Of Two Multivariate Analysis Techniques, Steven Rehse, Khozima Hamasha, Qassem I. Mohaidat, Russell A. Putnam, Ryan C. Woodman, Sunil Palchaudhuri Jan 2013

Sensitive And Specific Discrimination Of Pathogenic And Nonpathogenic Escherichia Coli Using Raman Spectroscopy - A Comparison Of Two Multivariate Analysis Techniques, Steven Rehse, Khozima Hamasha, Qassem I. Mohaidat, Russell A. Putnam, Ryan C. Woodman, Sunil Palchaudhuri

Physics Publications

The determination of bacterial identity at the strain level is still a complex and time-consuming endeavor. In this study, visible wavelength spontaneous Raman spectroscopy has been used for the discrimination of four closely related Escherichia coli strains: pathogenic enterohemorrhagic E. coli O157:H7 and non-pathogenic E. coli C, E. coli Hfr K-12, and E. coli HF4714. Raman spectra from 600 to 2000 cm-1 were analyzed with two multivariate chemometric techniques, principal component-discriminant function analysis and partial least squares-discriminant analysis, to determine optimal parameters for the discrimination of pathogenic E. coli from the non-pathogenic strains. Spectral preprocessing techniques such as smoothing with …


Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato Nov 2012

Spectral Engineering Of Optical Fiber Preforms Through Active Nanoparticle Doping, T. Lindstrom, E. Garber, D. Edmonson, T. Hawkins, Y. Chen, G. Turri, M. Bass, J. Ballato

Publications

Europium doped alkaline earth fluoride [Eu:AEF2 (AE = Ca, Sr, Ba)] nanoparticles were synthesized and systematically incorporated into the core of modified chemical vapor deposition (MCVD)-derived silica-based preforms by solution doping. The resulting preforms were examined to determine the impact of the nanoparticles chemistry on the spectroscopic behavior of the glass. The dominant existence of Eu3+ was demonstrated in all preforms, which is in contrast to conventional solution doped preforms employing dissolved europium salts where Eu2+ is primarily observed. Raman spectroscopy and fluorescence lifetime measurements indicated that the nanoparticles composition is effective in controlling, at a local chemical and structural …


Spectral Cross Correlation As A Supervised Approach For The Analysis Of Complex Raman Datasets: The Case Of Nanoparticles In Biological Cells, Mark Keating, Franck Bonnier, Hugh Byrne Oct 2012

Spectral Cross Correlation As A Supervised Approach For The Analysis Of Complex Raman Datasets: The Case Of Nanoparticles In Biological Cells, Mark Keating, Franck Bonnier, Hugh Byrne

Articles

Spectral Cross-correlation is introduced as a methodology to identify the presence and subcellular distribution of nanoparticles in cells. Raman microscopy is employed to spectroscopically image biological cells previously exposed to polystyrene nanoparticles, as a model for the study of nano-bio interactions. The limitations of previously deployed strategies of K-means clustering analysis and principal component analysis are discussed and a novel methodology of Spectral Cross Correlation Analysis is introduced and compared with the performance of Classical Least Squares Analysis, in both unsupervised and supervised modes. The previous study demonstrated the feasibility of using Raman spectroscopy to map cells and identify polystyrene …


Energy Scaling Of Nanosecond Gain-Switched Cr2+:Znse Lasers, Vladimir V. Fedorov, Igor S. Moskalev, M. S. Mirov, S. B. Mirov, Torrey J. Wagner, Matthew J. Bohn, Patrick A. Berry, K. L. Schepler Feb 2011

Energy Scaling Of Nanosecond Gain-Switched Cr2+:Znse Lasers, Vladimir V. Fedorov, Igor S. Moskalev, M. S. Mirov, S. B. Mirov, Torrey J. Wagner, Matthew J. Bohn, Patrick A. Berry, K. L. Schepler

Faculty Publications

In this paper, we report record nanosecond output energies of gain-switched CrZnSe lasers pumped by Q-switched CrTmHoYAG 100 ns at 2.096 microns and Raman shifted NdYAG lasers 7 ns at 1.906 microns. In these experiments we used Brewster cut CrZnSe gain elements with a chromium concentration of 8x1018cm-3. Under CrTmHoYAG pumping, the first CrZnSe laser demonstrated 3.1 mJ of output energy, 52 slope efficiency and 110 nm linewidth centered at a wavelength of 2.47 microns. Maximum output energy of the second CrZnSe laser reached 10.1 mJ under H2 Raman shifted NdYAG laser pumping. The slope …