Raman Scattering Spectroscopy to Measure Macular Pigment

Toward a novel framework for bloodstains dating by Raman spectroscopy: How to avoid sample photodamage and subsampling errors. Talanta IF 5. Unfortunately, the relevance of preserved evidence to the committed offence usually cannot be verified, because forensic experts are still incapable of providing an accurate estimate of the bloodstains’ age. An antidote to this impediment might be substituting the classical dating approach – founded on the application of calibration models – by the comparison problem addressed using likelihood ratio tests. The key aspect of this concept involves comparing the evidential data with results characterizing reference bloodstains, formed during the process of supervised ageing so as to reproduce the evidence. Since this comparison requires data that conveys information inherent to changes accompanying the process of blood decomposition, this study provided a Raman-based procedure, designated for probing into the chemistry of ageing bloodstains. To circumvent limitations experienced with single-point measurements – the risk of laser-induced degradation of hemoglobin and subsampling errors – the rotating mode of spectral acquisition was introduced. In order to verify the performance of this novel sampling method, obtained spectra were confronted with those acquired during conventional static measurements. The visual comparison was followed by analysis of data structure using regularized MANOVA, which boosted the variance between differently-aged samples while minimizing the variance observed for bloodstains deposited at the same time. Studies of relation between these variances demonstrated the superiority of novel procedure, as it provided Raman signatures that enabled a better distinction between differently-aged bloodstains.

Raman spectroscopy

Study record managers: refer to the Data Element Definitions if submitting registration or results information. This study will evaluate the ease and reliability of Raman scattering spectroscopy, a new technique to measure the amount of the pigment lutein in the retina, the light-sensitive tissue lining the back of the eye. The highest concentrations of lutein are in the center of the retina, called the macula, which is the area most important for fine, detailed vision.

The functions of lutein are not fully known. Besides absorbing blue light, it may help protect against abnormal changes in the retina, such as age-related macular degeneration.

To date skin cancers and benign skin lesions have been measured. Using partial least squares regression and linear discriminant analysis to analyze the.

N2 – Gamma hydroxybutyric acid GHB , also known as ‘liquid ecstasy’, has recently become associated with drug-facilitated sexual assaults, known colloquially as ‘date rape’, due to the ability of the drug to cause loss of consciousness. The drug is commonly found ‘spiked’ into alcoholic beverages, as alcohol increases its sedative effects. Gamma hydroxybutyric acid and the corresponding lactone gamma-butyrolactone GBL will reach an equilibrium in solution which favours the lactone in basic conditions and GHB in acidic conditions less than pH 4.

It has been demonstrated that we are able to detect GHB and GBL in a variety of containers including colourless and amber glass vials, plastic vials and polythene bags. We have also demonstrated the ability to detect both GBL and GHB in a range of liquid matrices simulating ‘spiked’ beverages. AB – Gamma hydroxybutyric acid GHB , also known as ‘liquid ecstasy’, has recently become associated with drug-facilitated sexual assaults, known colloquially as ‘date rape’, due to the ability of the drug to cause loss of consciousness.

Hargreaves Tasnim Munshi.

Towards Fingermark Dating: A Raman Spectroscopy Proof-of-Concept Study

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Negative date-effective uranium (eU) correlations in zircon from the Kaapvaal I used Raman spectroscopy to quantitatively and qualitatively.

Raman spectroscopy is an analytical technique where scattered light is used to measure the vibrational energy modes of a sample. It is named after the Indian physicist C. Raman who, together with his research partner K. Krishnan, was the first to observe Raman scattering in Raman spectroscopy extracts this information through the detection of Raman scattering from the sample.

When light is scattered by molecule, the oscillating electromagnetic field of a photon induces a polarisation of the molecular electron cloud which leaves the molecule in a higher energy state with the energy of the photon transferred to the molecule. This can be considered as the formation of a very short-lived complex between the photon and molecule which is commonly called the virtual state of the molecule.

Raman scattering

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Abstract The Fourier transform Raman vibrational spectra of five ancient molar teeth (burial periods ranging from to about years ago) were analysed in​.

Many Middle Stone Age sites in South Africa yielded hundreds, even thousands, of ochre pieces sometimes showing use traces. Less attention has been paid to the tools used for their processing. The tools were first examined with optical microscopy to detect areas of interest. Then, Raman micro-spectroscopy was performed on the residues present, as well as on random areas of tool surfaces.

These Raman signatures were compared to those obtained from the sediments and ochre samples recovered from the same layers. All tools exhibited red, orange and brown stains on their surfaces and these comprised iron oxides haematite and maghemite and oxyhydroxide goethite. The other compounds detected include amorphous carbon, quartz, anatase and manganese oxides.

All of these can occur within ochre, but they may alternatively be natural components of other rocks and sediments, formed secondarily by decay processes. However, the large and thick residues present on the surfaces of the artefacts imply their use for ochre processing microscopic observations and chemical analyses of the sediments and the local rocks showed that they contain only traces of haematite.

Ochre seems to have been the only material processed with these old Sibudu artefacts whereas in younger occupations, items such as bone were also processed with grindstones. The grinding tools are morphologically varied and the ochre pieces are both morphologically and chemically diverse. Ochre definitions can vary depending on the field of study for example, geology, archaeology or chemistry , its use and the period when it was used.

Petrographical and Mineralogical Applications of Raman Mapping

Typically this involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower energy. This is called normal Stokes Raman scattering. The effect is exploited by chemists and physicists to gain information about materials for a variety of purposes by performing various forms of Raman spectroscopy.

Keywords: dye; pigment; Raman spectroscopy; gas chromatography; writing extra inscriptions, signatures, and fake dates with ballpoint, gel.

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Raman fibre optic approach to artwork dating.

As a service to our authors and readers, this journal provides supporting information supplied by the authors. Technical support issues arising from supporting information other than missing files should be addressed to the authors. Raman spectroscopy is, herein, evaluated for the purpose of estimating the age of fingermarks deposits.

Copyright {\circledC} John Wiley & Sons, Ltd.”,. keywords = “Date rape drug​, GBL, GHB, Raman spectroscopy”,. author = “Victoria Brewster and Brewster.

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide. Vandenabeele UGent. During the last decades, Raman spectroscopy has grown from research laboratories to a well-established approach that is increasingly often used in archaeometry and conservation science. When looking at these research fields, some novel trends can be detected and therefore we would like to review the recent literature on the technical aspects and new evolutions of Raman spectroscopy applied to art analysis.

This article reviews Raman instrumentation, with a special focus on the use of mobile and portable instruments, recent developments in the field of surface-enhanced Raman spectroscopy SERS , and the introduction of spatially offset Raman spectroscopy SORS in the field of art and archaeology. This article is licensed under a Creative Commons Attribution 3.

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Then, Raman micro-spectroscopy was performed on the residues present, Stone Age sediments dating from 77, to 38, years ago (Fig.

Skip to Main Content. A not-for-profit organization, IEEE is the world’s largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. Personal Sign In. For IEEE to continue sending you helpful information on our products and services, please consent to our updated Privacy Policy. Email Address. Sign In. Real-time raman spectroscopy for non-invasive skin cancer detection – preliminary results Abstract: Raman spectroscopy is a non-invasive optical technique, which can assess molecular structures and conformations within biological tissue.

The probability of Raman scattering is inherently low such that previous clinical applications of Raman spectroscopy have been limited by long data acquisition times.

REAL-TIME HYDRAZINE MONITORING WITH SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS)

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The Marbles are still there, but the books have gone to the brand new British Library nearby and the Reading Room has become redundant. Sir Norman Foster, the architect of the revamped Reichstag masterminded the construction of a magnificent Education Centre in the rotunda and the meeting was held in one of its superb new lecture theatres. My first impression was one of surprise at the number of people attending.

I expected to see perhaps 30 faces, many of whom would be old friends. The friends were there, but most of the attendees, almost of them were from all over Europe and many indeed from the Art World. These were enthusiastic practitioners expert in Art History, Restoration, Conservation and Archaeology. The lecture programme was extensive and the posters many and very varied.

It is quite clear that Raman is now well on its way to becoming established as a primary tool in the analysis of artefacts. But what can Raman tell us? An amazing amount. There was so much on offer that I can only report a few examples. Professor Couprey using minute amounts of laser power examined the precious Fecamp Scriptorium dated between and AD. Two blue dyes were extensively used in this period based on Indigotin — an organic product and Lapis Lazuli — a mineral: similarly Minium and Vermillion in the red.

Surface-enhanced Spatially Offset Raman Spectroscopy (SESORS) in Tissue Analogs

Fingermarks have, for a long time, been vital in the forensic community for the identification of individuals, and a possibility to non-destructively date the fingermarks would of course be beneficial. Raman spectroscopy is, herein, evaluated for the purpose of estimating the age of fingermarks deposits. The degradation rates were accelerated, less pronounced for proteins, when samples were stored under ambient light conditions, likely owing to photo-oxidation.

Raman spectra are then detected as produced by the separated proteins or a legal analysis and makes no representation as to the accuracy of the date listed.

Forensic document examiners in the Department of Justice have identified specific needs in the analysis of intersecting lines with respect to sequence and dating of lines in questioned documents such as forgeries and alterations. Raman spectroscopy has great potential in forensics, in part because it is nondestructive to evidence. Raman has recently shown promise in successfully identifying and differentiating several different types of inks. There is, however, a shortfall in the ability to time-sequence marks, and to identify specific inks and pigments, especially in the case of intersecting lines.

To date, this has received little attention. One major problem is the fluorescence of paper fibers and inks which masks valuable spectral information that identifies the inks. Diffusion of inks across different layers of paper and other inks is another problem that could make time-sequencing lines very difficult. The goal of this project is to overcome the problem of fluorescence and to determine a method that successfully sequences intersecting lines.

Raman spectroscopy will be used in various modes such as changing wavelengths of the lasers, scanning at different depths in the sample, and employing surface-enhanced Raman scattering.

Resonance Raman spectroscopy for redox biology research webinar