Science.gov

Sample records for raman spectroscopy applied

  1. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1986-04-01

    The period of this review is from late 1983 to late 1985. During this time over 5000 papers have appeared in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to several new areas of study. As in the previous review in this series most of the applications relevant to solids are covered in one or other of the ten categories, which are the same as those used previously. However, aspects relating to solids which are not covered elsewhere include general reviews and the specific field of semiconductors. This is an area of great current interest in terms of Raman spectroscopy and the characterization of semiconductor materials and surfaces has been reported. Raman scattering also provides a new probe for the elucidation of structural properties of microcrystalline silicon and resonance Raman scattering in silicon at elevated temperatures has been studied. Many studies on carbon have also appeared in the literature including that of the various types of carbon, the use of Raman scattering to investigate disorder and crystallite formation in annealed carbon, in situ studies of intercalation kinetics, structural aspects of cokes and coals, and instrumentation for coal gasification. Raman spectroscopy has been applied to such diverse systems as organic crystals, the determination of modifications in layered crystals, the detection of explosives on silica gel or carbon, diagnostics of heterogeneous chemical processes, and a study of tungsten-halogen bulbs. Laser Raman spectroscopy has also been coupled with liquid chromatography and phase-resolved background suppression has been used to enhance Raman spectra. 397 references.

  2. Surface-enhanced Raman spectroscopy applied to food safety.

    PubMed

    Craig, Ana Paula; Franca, Adriana S; Irudayaraj, Joseph

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) is an advanced Raman technique that enhances the vibrational spectrum of molecules adsorbed on or in the vicinity of metal particles and/or surfaces. Because of its readiness, sensitivity, and minimum sample preparation requirements, SERS is being considered as a powerful technique for food inspection. Key aspects of food-safety assurance, spectroscopy methods, and SERS are briefly discussed in an extended introduction of this review. The recent and potential advances in SERS are highlighted in sections that deal with the (a) detection of food-borne pathogenic microorganisms and (b) the detection of food contaminants and adulteration, concentrated specifically on antibiotics, drugs, hormones, melamine, and pesticides. This review provides an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for food-safety assessment. PMID:23297774

  3. Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Gerrard, Donald L.

    1984-01-01

    Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

  4. Raman Spectroscopy Applied to Mars Water Cycle Studies

    NASA Astrophysics Data System (ADS)

    Nikolakakos, G.; Whiteway, J. A.

    2014-12-01

    One of the key findings during the Phoenix and Mars Science Laboratory landed Mars missions has been the detection of perchlorate, a highly deliquescent salt. Perchlorates are of great interest on Mars due to their high affinity for water vapour as well as their ability to greatly depress the freezing point of water when in solution. This has intriguing biological implications as resulting brines could potentially provide a habitable environment for living organisms. Additionally, it has been speculated that these salts may play a significant role in influencing the hydrological cycle on Mars. In order to experimentally study brine formation on Mars and assess the feasibility of a future landed detection tool, a stand-off Raman spectroscopy instrument and environmental simulation chamber have been developed at York University. A sample of magnesium perchlorate has been subjected to the water vapour pressure, background pressure and temperatures found at polar Martian latitudes. Results indicate that at a water vapour pressure of ~20 Pa, Raman spectroscopy is able to detect the onset of brine formation and provide an estimate of the quantity of water taken up by the sample. At the lower water vapour pressures typically found on Mars ( ~1 Pa), it appears that slower dynamics inhibit the onset of water uptake over relevant time scales. The experimental setup and current results will be presented.

  5. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1988-06-15

    The period of this review is from late 1985 to late 1987. During this time over 6000 papers have been published in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to new areas of study. This article covers only those papers that are relevant to the analytical chemist and this necessitates a highly selective approach. There are some areas that have been the subject of many papers with relatively few being of analytical interest. In such cases the reader is referred to appropriate reviews which are detailed in this section.

  6. Raman spectroscopy and capillary electrophoresis applied to forensic colour inkjet printer inks analysis.

    PubMed

    Król, Małgorzata; Karoly, Agnes; Kościelniak, Paweł

    2014-09-01

    Forensic laboratories are increasingly engaged in the examination of fraudulent documents, and what is important, in many cases these are inkjet-printed documents. That is why systematic approaches to inkjet printer inks comparison and identification have been carried out by both non-destructive and destructive methods. In this study, micro-Raman spectroscopy and capillary electrophoresis (CE) were applied to the analysis of colour inkjet printer inks. Micro-Raman spectroscopy was used to study the chemical composition of colour inks in situ on a paper surface. It helps to characterize and differentiate inkjet inks, and can be used to create a spectra database of inks taken from different cartridge brands and cartridge numbers. Capillary electrophoresis in micellar electrophoretic capillary chromatography mode was applied to separate colour and colourless components of inks, enabling group identification of those components which occur in a sufficient concentration (giving intensive peaks). Finally, on the basis of the obtained results, differentiation of the analysed inks was performed. Twenty-three samples of inkjet printer inks were examined and the discriminating power (DP) values for both presented methods were established in the routine work of experts during the result interpretation step. DP was found to be 94.0% (Raman) and 95.6% (CE) when all the analysed ink samples were taken into account, and it was 96.7% (Raman) and 98.4% (CE), when only cartridges with different index numbers were considered. PMID:25062531

  7. Raman spectroscopy of composites

    SciTech Connect

    Young, R.J.; Andrews, M.C.; Yang, X.; Huang, Y.L.; Gu, X.; Day, R.J.

    1994-12-31

    It is demonstrated that Raman Spectroscopy can be used to follow the micromechanics of the deformation of high-performance fibers within composites. The technique can be applied to a wide range of fiber systems including aramids, carbon and ceramic (using fluorescence spectroscopy) fibers. Well-defined Raman spectra are obtained and the position of the Raman bands shift on the application of stress or strain. It is possible to determine the point-to-point variation of strain along an individual fiber inside a transparent matrix under any general state of stress or strain. Examples are given of the use of the technique to study a variety of phenomena in a wide range of composite systems. The phenomena investigated include thermal stresses, fiber/matrix adhesion, matrix yielding for both fragmentation and pull-out tests. The systems studied include aramid/epoxy, carbon/epoxy and ceramic-fiber/glass composites.

  8. In vivo Raman spectroscopy detects increased epidermal antioxidative potential with topically applied carotenoids

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Caspers, P. J.; van der Pol, A.; Richter, H.; Patzelt, A.; Zastrow, L.; Darvin, M.; Sterry, W.; Fluhr, J. W.

    2009-01-01

    In the present study, the distribution of the carotenoids as a marker for the complete antioxidative potential in human skin was investigated before and after the topical application of carotenoids by in vivo Raman spectroscopy with an excitation wavelength of 785 nm. The carotenoid profile was assessed after a short term topical application in 4 healthy volunteers. In the untreated skin, the highest concentration of natural carotenoids was detected in different layers of the stratum corneum (SC) close to the skin surface. After topical application of carotenoids, an increase in the antioxidative potential in the skin could be observed. Topically applied carotenoids penetrate deep into the epidermis down to approximately 24 μm. This study supports the hypothesis that antioxidative substances are secreted via eccrine sweat glands and/or sebaceous glands to the skin surface. Subsequently they penetrate into the different layers of the SC.

  9. Solid state characterization of chloramphenicol palmitate. Raman spectroscopy applied to pharmaceutical polymorphs

    NASA Astrophysics Data System (ADS)

    Gamberini, M. C.; Baraldi, C.; Tinti, A.; Rustichelli, C.; Ferioli, V.; Gamberini, G.

    2006-03-01

    A pharmaceutical active compound, chloramphenicol palmitate, appears in three polymorphic forms, that can be observed at room temperature. The stable form A (biologically inactive modification), the meta-stable form B (active modification) and unstable form C were found to have distinct Raman spectra, with bands attributable to the different polymorphs. The use of hot-stage Raman microscopy (the direct coupling of Raman microscopy and hot-stage) is demonstrated for the drug substance chloramphenicol palmitate form C. All modifications of form C were produced and identified by hot-stage Raman microscopy. A close correlation of thermal and spectroscopic information was achieved by this combination of techniques. As reported in several pharmacopoeias, the content of form A should be less than 10%; therefore, a mixture of 10% (w/w) A in B was prepared, and the presence of the characteristic bands of form A after subtraction of the pure B was revealed. Moreover, mixtures between 2 and 12% (w/w) A in B were investigated and the intensity ratio (as peak area) I 413-435/I 1035-1158 as a function of A percentage has been demonstrated to show a linear trend. Other methods for the characterization of polymorphs were used: Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD).

  10. FTIR and Raman Spectroscopy Applied to Dementia Diagnosis Through Analysis of Biological Fluids.

    PubMed

    Lopes, Jéssica; Correia, Marta; Martins, Ilka; Henriques, Ana Gabriela; Delgadillo, Ivonne; da Cruz E Silva, Odete; Nunes, Alexandra

    2016-04-01

    To date, it is still difficult to perform an early and accurate diagnosis of dementia, therefore significant research has focused on finding new dementia biomarkers that can aid in this respect. There is an urgent need for non-invasive, rapid, and relatively inexpensive procedures for early diagnostics. Studies have demonstrated that of spectroscopic techniques, such as Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy could be a useful and accurate procedure to diagnose dementia. Given that several biochemical mechanisms related to neurodegeneration and dementia can lead to changes in plasma components and others peripheral body fluids; blood-based samples coupled to spectroscopic analyses can be used as a simple and less invasive approach. PMID:27079713

  11. Auger resonant Raman spectroscopy

    SciTech Connect

    Azuma, Y.; LeBrun, T.; MacDonald, M.; Southworth, S.H.

    1995-08-01

    As noted above, traditional spectroscopy of the electronic structure of the inner shells of atoms, molecules, and solids is limited by the lifetime broadening of the core-excited states. This limitation can also be avoided with the non-radiative analog of X-ray Raman scattering - resonant Auger Raman spectroscopy. We have used this technique to study the K-shell excitation spectrum of argon as the photon energy is continuously scanned across threshold.

  12. Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Dietze, Daniel R; Mathies, Richard A

    2016-05-01

    Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast nonlinear optical technique that provides vibrational structural information with high temporal (sub-50 fs) precision and high spectral (10 cm(-1) ) resolution. Since the first full demonstration of its capabilities ≈15 years ago, FSRS has evolved into a mature technique, giving deep insights into chemical and biochemical reaction dynamics that would be inaccessible with any other technique. It is now being routinely applied to virtually all possible photochemical reactions and systems spanning from single molecules in solution to thin films, bulk crystals and macromolecular proteins. This review starts with an historic overview and discusses the theoretical and experimental concepts behind this technology. Emphasis is put on the current state-of-the-art experimental realization and several variations of FSRS that have been developed. The unique capabilities of FSRS are illustrated through a comprehensive presentation of experiments to date followed by prospects. PMID:26919612

  13. Surface-Enhanced Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Garrell, Robin L.

    1989-01-01

    Reviews the basis for the technique and its experimental requirements. Describes a few examples of the analytical problems to which surface-enhanced Raman spectroscopy (SERS) has been and can be applied. Provides a perspective on the current limitations and frontiers in developing SERS as an analytical technique. (MVL)

  14. Raman spectroscopy in astrobiology.

    PubMed

    Jorge Villar, Susana E; Edwards, Howell G M

    2006-01-01

    Raman spectroscopy is proposed as a valuable analytical technique for planetary exploration because it is sensitive to organic and inorganic compounds and able to unambiguously identify key spectral markers in a mixture of biological and geological components; furthermore, sample manipulation is not required and any size of sample can be studied without chemical or mechanical pretreatment. NASA and ESA are considering the adoption of miniaturised Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for extinct or extant life signals. In this paper we review the advantages and limitations of Raman spectroscopy for the analysis of complex specimens with relevance to the detection of bio- and geomarkers in extremophilic organisms which are considered to be terrestrial analogues of possible extraterrestial life that could have developed on planetary surfaces. PMID:16456933

  15. Fiber enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Frosch, T.; Yan, D.; Hanf, S.; Popp, J.

    2014-05-01

    Fiber enhanced Raman sensing is presented for versatile and extremely sensitive analysis of pharmaceutical drugs and biogenic gases. Elaborated micro-structured optical fibers guide the light with very low losses within their hollow core and provide at the same time a miniaturized sample container for the analytes. Thus, fiber enhanced Raman spectroscopy (FERS) allows for chemically selective detection of minimal sample amounts with high sensitivity. Two examples are presented in this contribution: (i) the detection of picomolar concentrations of pharmaceutical drugs; and (ii) the analysis of biogenic gases within a complex mixture of gases with analytical sensitivities in the ppm range.

  16. A new high-resolution, high-throughput spectrometer: first experience as applied to Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Meade, Jeffrey T.; Behr, Bradford B.; Hajian, Arsen R.

    2012-06-01

    The classic trade-off between resolution and throughput in a dispersive spectrometer is overcome using virtual slit technology. An optimized spectrometer designed from the ground up to incorporate a virtual slit is experimentally demonstrated by Raman experiments.

  17. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    SciTech Connect

    Meyer, Matthew W.

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  18. Applications of Raman spectroscopy in life science

    NASA Astrophysics Data System (ADS)

    Martin, Airton A.; T. Soto, Cláudio A.; Ali, Syed M.; Neto, Lázaro P. M.; Canevari, Renata A.; Pereira, Liliane; Fávero, Priscila P.

    2015-06-01

    Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

  19. Fast label-free detection of Legionella spp. in biofilms by applying immunomagnetic beads and Raman spectroscopy.

    PubMed

    Kusić, Dragana; Rösch, Petra; Popp, Jürgen

    2016-03-01

    Legionellae colonize biofilms, can form a biofilm by itself and multiply intracellularly within the protozoa commonly found in water distribution systems. Approximately half of the known species are pathogenic and have been connected to severe multisystem Legionnaires' disease. The detection methods for Legionella spp. in water samples are still based on cultivation, which is time consuming due to the slow growth of this bacterium. Here, we developed a cultivation-independent, label-free and fast detection method for legionellae in a biofilm matrix based on the Raman spectroscopic analysis of isolated single cells via immunomagnetic separation (IMS). A database comprising the Raman spectra of single bacterial cells captured and separated from the biofilms formed by each species was used to build the identification method based on a support vector machine (SVM) discriminative classifier. The complete method allows the detection of Legionella spp. in 100 min. Cross-reactivity of Legionella spp. specific immunomagnetic beads to the other studied genera was tested, where only small cell amounts of Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli compared to the initial number of cells were isolated by the immunobeads. Nevertheless, the Raman spectra collected from isolated non-targeted bacteria were well-discriminated from the Raman spectra collected from isolated Legionella cells, whereby the Raman spectra of the independent dataset of Legionella strains were assigned with an accuracy of 98.6%. In addition, Raman spectroscopy was also used to differentiate between isolated Legionella species. PMID:26915495

  20. Transcutaneous Raman Spectroscopy of Bone

    NASA Astrophysics Data System (ADS)

    Maher, Jason R.

    Clinical diagnoses of bone health and fracture risk typically rely upon measurements of bone density or structure, but the strength of a bone is also dependent upon its chemical composition. One technology that has been used extensively in ex vivo, exposed-bone studies to measure the chemical composition of bone is Raman spectroscopy. This spectroscopic technique provides chemical information about a sample by probing its molecular vibrations. In the case of bone tissue, Raman spectra provide chemical information about both the inorganic mineral and organic matrix components, which each contribute to bone strength. To explore the relationship between bone strength and chemical composition, our laboratory has contributed to ex vivo, exposed-bone animal studies of rheumatoid arthritis, glucocorticoid-induced osteoporosis, and prolonged lead exposure. All of these studies suggest that Raman-based predictions of biomechanical strength may be more accurate than those produced by the clinically-used parameter of bone mineral density. The utility of Raman spectroscopy in ex vivo, exposed-bone studies has inspired attempts to perform bone spectroscopy transcutaneously. Although the results are promising, further advancements are necessary to make non-invasive, in vivo measurements of bone that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based upon fitting with spectral libraries derived from separately-acquired measurements of the underlying tissue components. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both soft tissue and bone and was applied to experimental data in order to transcutaneously detect, to our knowledge for the first time, age- and disease-related spectral

  1. Raman Spectroscopy of Cocrystals

    NASA Astrophysics Data System (ADS)

    Rooney, Frank; Reardon, Paul; Ochoa, Romulo; Abourahma, Heba; Marti, Marcus; Dimeo, Rachel

    2010-02-01

    Cocrystals are a class of compounds that consist of two or more molecules that are held together by hydrogen bonding. Pharmaceutical cocrystals are those that contain an active pharmaceutical ingredient (API) as one of the components. Pharmaceutical cocrystals are of particular interest and have gained a lot of attention in recent years because they offer the ability to modify the physical properties of the API, like solubility and bioavailability, without altering the chemical structure of the API. The APIs that we targeted for our studies are theophylline (Tp) and indomethacin (Ind). These compounds have been mixed with complementary coformers (cocrystal former) that include acetamide (AcONH2), melamine (MLM), nicotinic acid (Nic-COOH), 4-cyanopyridine (4-CNPy) and 4-aminopyridine (4-NH2Py). Raman spectroscopy has been used to characterize these cocrystals. Spectra of the cocrystals were compared to those of the coformers to analyze for peak shifts, specifically those corresponding to hydrogen bonding. A 0.5 m CCD Spex spectrometer was used, in a micro-Raman setup, for spectral analysis. An Argon ion Coherent laser at 514.5 nm was used as the excitation source. )

  2. Online fluorescence suppression in modulated Raman spectroscopy.

    PubMed

    De Luca, Anna Chiara; Mazilu, Michael; Riches, Andrew; Herrington, C Simon; Dholakia, Kishan

    2010-01-15

    Label-free chemical characterization of single cells is an important aim for biomedical research. Standard Raman spectroscopy provides intrinsic biochemical markers for noninvasive analysis of biological samples but is often hindered by the presence of fluorescence background. In this paper, we present an innovative modulated Raman spectroscopy technique to filter out the Raman spectra from the fluorescence background. The method is based on the principle that the fluorescence background does not change whereas the Raman scattering is shifted by the periodical modulation of the laser wavelength. Exploiting this physical property and importantly the multichannel lock-in detection of the Raman signal, the modulation technique fulfills the requirements of an effective fluorescence subtraction method. Indeed, once the synchronization and calibration procedure is performed, minimal user intervention is required, making the method online and less time-consuming than the other fluorescent suppression methods. We analyze the modulated Raman signal and shifted excitation Raman difference spectroscopy (SERDS) signal of 2 mum-sized polystyrene beads suspended in a solution of fluorescent dye as a function of modulation rate. We show that the signal-to-noise ratio of the modulated Raman spectra at the highest modulation rate is 3 times higher than the SERDS one. To finally evaluate the real benefits of the modulated Raman spectroscopy, we apply our technique to Chinese hamster ovary cells (CHO). Specifically, by analyzing separate spectra from the membrane, cytoplasm, and nucleus of CHO cells, we demonstrate the ability of this method to obtain localized sensitive chemical information from cells, away from the interfering fluorescence background. In particular, statistical analysis of the Raman data and classification using PCA (principal component analysis) indicate that our method allows us to distinguish between different cell locations with higher sensitivity and

  3. NanoSIMS and Micro-Raman Spectroscopy applied to the Analysis of Uranium Oxyfluoride Particles for Nuclear Safeguards

    NASA Astrophysics Data System (ADS)

    Kips, R.; Kristo, M.; Crowhurst, J.; Stefaniak, E.; Hutcheon, I. D.

    2010-12-01

    Environmental swipe sampling is used by safeguards organizations to verify the absence of undeclared nuclear activities. Particulate material collected in environmental swipe samples is typically analyzed for its uranium isotopic composition. At enrichment facilities, these swipe samples often contain UO2F2 particles formed from the hydrolysis of uranium hexafluoride gas. Since UO2F2 particulate material has been found to be unstable with respect to the loss of fluorine (J.A. Carter et al. Task A.200.3 K/NSP-777, 1998) the measurement of the residual amount of fluorine has the potential of placing boundaries on the particle’s age and exposure history. To investigate the decomposition of UO2F2 and its potential applications in nuclear safeguards and nuclear forensics, a suite of micro-analytical tools was applied to a set of lab-synthesized UO2F2 particles. Samples were either stored in an inert atmosphere or exposed to different levels of humidity, temperature and light to identify those environmental conditions that accelerate the decomposition of UO2F2. Given the small size of the particles, secondary ion mass spectrometry with nanometer-scale spatial resolution (NanoSIMS) was used to measure the relative amount of fluorine. The elemental data from the NanoSIMS was complemented with micro-Raman spectroscopy for molecular fingerprinting. These measurements showed that even though the decomposition of UO2F2 generally happens very slowly, subtle differences can be distinguished depending on the environmental conditions to which they were exposed. The exposure to humidity was identified as the main factor accelerating the loss of fluorine in UO2F2 particles. Particles exposed to 30 % relative humidity and higher showed a decrease in the relative amount of fluorine and a shift of the UO22+ symmetric stretching frequency towards lower frequencies. These changes were attributed to an increase in hydration of the UO2F2 particles. This work was performed under the

  4. Raman spectroscopy in halophile research.

    PubMed

    Jehlička, Jan; Oren, Aharon

    2013-01-01

    Raman spectroscopy plays a major role in robust detection of biomolecules and mineral signatures in halophile research. An overview of Raman spectroscopic investigations in halophile research of the last decade is given here to show advantages of the approach, progress made as well as limits of the technique. Raman spectroscopy is an excellent tool to monitor and identify microbial pigments and other biomolecules in extant and extinct halophile biomass. Studies of bottom gypsum crusts from salterns, native evaporitic sediments, halite inclusions, and endoliths as well as cultures of halophilic microorganisms permitted to understand the content, distribution, and behavior of important molecular species. The first papers describing Raman spectroscopic detection of microbiological and geochemical key markers using portable instruments are highlighted as well. PMID:24339823

  5. Raman spectroscopy in halophile research

    PubMed Central

    Jehlička, Jan; Oren, Aharon

    2013-01-01

    Raman spectroscopy plays a major role in robust detection of biomolecules and mineral signatures in halophile research. An overview of Raman spectroscopic investigations in halophile research of the last decade is given here to show advantages of the approach, progress made as well as limits of the technique. Raman spectroscopy is an excellent tool to monitor and identify microbial pigments and other biomolecules in extant and extinct halophile biomass. Studies of bottom gypsum crusts from salterns, native evaporitic sediments, halite inclusions, and endoliths as well as cultures of halophilic microorganisms permitted to understand the content, distribution, and behavior of important molecular species. The first papers describing Raman spectroscopic detection of microbiological and geochemical key markers using portable instruments are highlighted as well. PMID:24339823

  6. Raman spectroscopy of shocked water

    SciTech Connect

    Holmes, N.C.; Mitchell, A.C.; Nellis, W.J.; Graham, W.B.; Walrafen, G.E.

    1983-07-01

    Raman scattering has been used extensively to study the vibrational and rotational properties of molecules under a variety of conditions. Here, interest is in the behavior of water molecules shocked to high pressures and temperatures. Behind the shock front the water molecules undergo changes in bonding and the molecules may become ionized. Raman spectroscopy can be used to determine the molecular species behind the shock front. In addition, changes in Raman spectra can yield information regarding inter- and intramolecular potentials and the temperature behind the shock front.

  7. Raman Spectroscopy of Microbial Pigments

    PubMed Central

    Edwards, Howell G. M.; Oren, Aharon

    2014-01-01

    Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

  8. Applications of Raman Spectroscopy to Virology and Microbial Analysis

    NASA Astrophysics Data System (ADS)

    Harz, Michaela; Stöckel, Stephan; Ciobotă, Valerian; Cialla, Dana; Rösch, Petra; Popp, Jürgen

    This chapter reports from the utilization of Raman spectroscopic techniques like Raman microscopy, Raman optical activity (ROA), UV-resonance Raman (UVRR)-spectroscopy, surface enhanced Raman spectroscopy (SERS), and tip-enhanced Raman spectroscopy (TERS) for the investigation of viruses and microorganisms, especially bacteria and yeasts for medical and pharmaceutical applications. The application of these Raman techniques allows for the analysis of chemical components of cells and subcellular regions, as well as the monitoring of chemical differences occurring as a result of the growth of microorganisms. In addition, the interaction of microorganisms with active pharmaceutical agents can be investigated. In combination with chemometric methods Raman spectroscopy can also be applied to identify microorganisms both in micro colonies and even on single cells.

  9. Raman Spectroscopy of Amorphous Carbon

    SciTech Connect

    Tallant, D.R.; Friedmann, T.A.; Missert, N.A.; Siegal, M.P.; Sullivan, J.P.

    1998-01-01

    Amorphous carbon is an elemental form of carbon with low hydrogen content, which may be deposited in thin films by the impact of high energy carbon atoms or ions. It is structurally distinct from the more well-known elemental forms of carbon, diamond and graphite. It is distinct in physical and chemical properties from the material known as diamond-like carbon, a form which is also amorphous but which has a higher hydrogen content, typically near 40 atomic percent. Amorphous carbon also has distinctive Raman spectra, whose patterns depend, through resonance enhancement effects, not only on deposition conditions but also on the wavelength selected for Raman excitation. This paper provides an overview of the Raman spectroscopy of amorphous carbon and describes how Raman spectral patterns correlate to film deposition conditions, physical properties and molecular level structure.

  10. Chemical analysis of acoustically levitated drops by Raman spectroscopy.

    PubMed

    Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

    2009-07-01

    An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension. PMID:19418043

  11. Raman spectroscopy of illicit substances

    NASA Astrophysics Data System (ADS)

    Stokes, Robert J.; Faulds, Karen; Smith, W. Ewen

    2007-10-01

    Raman spectroscopy provides a very effective method of identifying an illicit substance in situ without separation or contact other than with a laser beam. The equipment required is steadily improving and is now reliable and simple to operate. Costs are also coming down and hand held portable spectrometers are proving very effective. The main limitations on the use of the technique are that it is insensitive in terms of the number of incident photons converted into Raman scattered photons and fluorescence produced in the sample by the incident radiation interferes. Newer methods, still largely in the development phase, will increase the potential for selected applications. The use of picosecond pulsed lasers can discriminate between fluorescence and Raman scattering and this has been used in the laboratory to examine street samples of illicit drugs. Surface-enhanced Raman scattering, in which the analyte requires to be adsorbed onto a roughened metal surface, creates a sensitivity to compete with fluorescence and quenches fluorescence for molecules on a surface. This provides the ability to detect trace amounts of substances in some cases. The improving optics, detection capability and the reliability of the new methods indicate that the potential for the use of Raman spectroscopy for security purposes will increase with time.

  12. Gradient temperature Raman spectroscopy identifies flexible sites in proline and alanine peptides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuous thermo dynamic Raman spectroscopy (TDRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDRS...

  13. Raman spectroscopy of bone metastasis

    NASA Astrophysics Data System (ADS)

    Esmonde-White, Karen A.; Sottnik, Joseph; Morris, Michael; Keller, Evan

    2012-02-01

    Raman spectroscopy of bone has been used to characterize chemical changes occurring in diseases such as osteoporosis, osteoarthritis and osteomyelitis. Metastasis of cancer into bone causes changes to bone quality that are similar to those observed in osteoporosis, such as decreased bone strength, but with an accelerated timeframe. In particular, osteolytic (bone degrading) lesions in bone metastasis have a marked effect on patient quality of life because of increased risk of fractures, pain, and hypercalcemia. We use Raman spectroscopy to examine bone from two different mouse models of osteolytic bone metastasis. Raman spectroscopy measures physicochemical information which cannot be obtained through standard biochemical and histological measurements. This study was reviewed and approved by the University of Michigan University Committee on the Care and Use of Animals. Two mouse models of prostate cancer bone metastasis, RM1 (n=3) and PC3-luc (n=4) were examined. Tibiae were injected with RM1 or PC3-luc cancer cells, while the contralateral tibiae received a placebo injection for use as controls. After 2 weeks of incubation, the mice were sacrificed and the tibiae were examined by Raman microspectroscopy (λ=785 nm). Spectroscopic markers corresponding to mineral stoichiometry, bone mineralization, and mineral crystallinity were compared in spectra from the cancerous and control tibiae. X-ray imaging of the tibia confirmed extensive osteolysis in the RM1 mice, with tumor invasion into adjoining soft tissue and moderate osteolysis in the PC3-luc mice. Raman spectroscopic markers indicate that osteolytic lesions are less mineralized than normal bone tissue, with an altered mineral stoichiometry and crystallinity.

  14. FT-Raman Spectroscopy: A Catalyst for the Raman Explosion?

    ERIC Educational Resources Information Center

    Chase, Bruce

    2007-01-01

    The limitations of Fourier transform (FT) Raman spectroscopy, which is used to detect and analyze the scattered radiation, are discussed. FT-Raman has served to revitalize a field that was lagging and the presence of Raman instrumentation as a routine analytical tool is established for the foreseeable future.

  15. Raman Spectroscopy of Ocular Tissue

    NASA Astrophysics Data System (ADS)

    Ermakov, Igor V.; Sharifzadeh, Mohsen; Gellermann, Warner

    The optically transparent nature of the human eye has motivated numerous Raman studies aimed at the non-invasive optical probing of ocular tissue components critical to healthy vision. Investigations include the qualitative and quantitative detection of tissue-specific molecular constituents, compositional changes occurring with development of ocular pathology, and the detection and tracking of ocular drugs and nutritional supplements. Motivated by a better understanding of the molecular mechanisms leading to cataract formation in the aging human lens, a great deal of work has centered on the Raman detection of proteins and water content in the lens. Several protein groups and the hydroxyl response are readily detectable. Changes of protein compositions can be studied in excised noncataractous tissue versus aged tissue preparations as well as in tissue samples with artificially induced cataracts. Most of these studies are carried out in vitro using suitable animal models and conventional Raman techniques. Tissue water content plays an important role in optimum light transmission of the outermost transparent ocular structure, the cornea. Using confocal Raman spectroscopy techniques, it has been possible to non-invasively measure the water to protein ratio as a measure of hydration status and to track drug-induced changes of the hydration levels in the rabbit cornea at various depths. The aqueous humor, normally supplying nutrients to cornea and lens, has an advantageous anterior location for Raman studies. Increasing efforts are pursued to non-invasively detect the presence of glucose and therapeutic concentrations of antibiotic drugs in this medium. In retinal tissue, Raman spectroscopy proves to be an important tool for research into the causes of macular degeneration, the leading cause of irreversible vision disorders and blindness in the elderly. It has been possible to detect the spectral features of advanced glycation and advanced lipooxydation end products in

  16. Raman and Photoluminescence Spectroscopy in Mineral Identification

    NASA Astrophysics Data System (ADS)

    Kuehn, J. W.

    2014-06-01

    Raman spectroscopy is particularly useful for rapid identification of minerals and gemstones. Raman spectrometers also allow PL studies for authentication of samples and geological provenance, diamond type screening and detection of HPHT treatments.

  17. Characterization of Kevlar Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

    2007-01-01

    This paper explores the characterization of Kevlar composite materials using Raman spectroscopy. The goal of the research is to develop and understand the Raman spectrum of Kevlar materials to provide a foundation for the development of nondestructive evaluation (NDE) technologies based on the interaction of laser light with the polymer Kevlar. The paper discusses the fundamental aspects of experimental characterization of the spectrum of Kevlar, including the effects of incident wavelength, polarization and laser power. The effects of environmental exposure of Kevlar materials on certain characteristics of its Raman spectrum are explored, as well as the effects of applied stress. This data may provide a foundation for the development of NDE technologies intended to detect the in-situ deterioration of Kevlar materials used for engineering applications that can later be extended to other materials such as carbon fiber composites.

  18. Raman spectroscopy of triolein under high pressures

    NASA Astrophysics Data System (ADS)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  19. Raman spectroscopies in shock-compressed materials

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.; Shaner, J.W.

    1983-01-01

    Spontaneous Raman spectroscopy, stimulated Raman scattering and coherent anti-Stokes Raman scattering have been used to measure temperatures and changes in molecular vibrational frequencies for detonating and shocked materials. Inverse Raman and Raman induced Kerr effect spectroscopies have been suggested as diagnostic probes for determining and phenomenology of shock-induced chemical reactions. The practicality, advantages, and disadvantages of using Raman scattering techniques as diagnostic probes of microscopic phenomenology through and immediately behind the shock front of shock-compressed molecular systems are discussed.

  20. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

    PubMed Central

    Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

    2015-01-01

    The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

  1. Raman Spectroscopy and Related Techniques in Biomedicine

    PubMed Central

    Downes, Andrew; Elfick, Alistair

    2010-01-01

    In this review we describe label-free optical spectroscopy techniques which are able to non-invasively measure the (bio)chemistry in biological systems. Raman spectroscopy uses visible or near-infrared light to measure a spectrum of vibrational bonds in seconds. Coherent anti-Stokes Raman (CARS) microscopy and stimulated Raman loss (SRL) microscopy are orders of magnitude more efficient than Raman spectroscopy, and are able to acquire high quality chemically-specific images in seconds. We discuss the benefits and limitations of all techniques, with particular emphasis on applications in biomedicine—both in vivo (using fiber endoscopes) and in vitro (in optical microscopes). PMID:21151763

  2. Diagnosing breast cancer by using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Haka, Abigail S.; Shafer-Peltier, Karen E.; Fitzmaurice, Maryann; Crowe, Joseph; Dasari, Ramachandra R.; Feld, Michael S.

    2005-08-01

    We employ Raman spectroscopy to diagnose benign and malignant lesions in human breast tissue based on chemical composition. In this study, 130 Raman spectra are acquired from ex vivo samples of human breast tissue (normal, fibrocystic change, fibroadenoma, and infiltrating carcinoma) from 58 patients. Data are fit by using a linear combination model in which nine basis spectra represent the morphologic and chemical features of breast tissue. The resulting fit coefficients provide insight into the chemical/morphological makeup of the tissue and are used to develop diagnostic algorithms. The fit coefficients for fat and collagen are the key parameters in the resulting diagnostic algorithm, which classifies samples according to their specific pathological diagnoses, attaining 94% sensitivity and 96% specificity for distinguishing cancerous tissues from normal and benign tissues. The excellent results demonstrate that Raman spectroscopy has the potential to be applied in vivo to accurately classify breast lesions, thereby reducing the number of excisional breast biopsies that are performed. Author contributions: M.F., J.C., R.R.D., and M.S.F. designed research; A.S.H. and K.E.S.-P. performed research; A.S.H. and M.F. analyzed data; and A.S.H. wrote the paper.This paper was submitted directly (Track II) to the PNAS office.Abbreviations: DEH, ductal epithelial hyperplasia; ROC, receiver operating characteristic; N/C, nuclear-to-cytoplasm.

  3. Raman spectroscopy of transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Saito, R.; Tatsumi, Y.; Huang, S.; Ling, X.; Dresselhaus, M. S.

    2016-09-01

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs.

  4. Raman spectroscopy of transition metal dichalcogenides.

    PubMed

    Saito, R; Tatsumi, Y; Huang, S; Ling, X; Dresselhaus, M S

    2016-09-01

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs. PMID:27388703

  5. Raman spectroscopy application to analyses of components in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhang, Guoping

    2006-09-01

    The characterization of species in aqueous solutions has presented a challenge to analytical and physical chemist, because the JR absorption of the aqueous solvent is so intense that it becomes difficult to observe the solute in the water by JR absorption. In contrast, Raman spectrum of the solute is unaffected by the water, so the weak scattering of water makes the technique well suited to aqueous samples, and the Raman spectrum exhibits well-defined bands corresponding to fundamental modes of vibration. In addition, Raman spectroscopy has some inherent advantages in aqueous solution analysis, because the spectral features of signals from different species are much more distinct, and it provides characteristic signatures for samples, such as blood, protein and cholesterol. All the advantages make Raman spectroscopy be a potential alternative for the study of aqueous solutions. Now, Raman spectroscopy has been applied to studying samples in aqueous solutions, blood serum, intracellular protein levels. Now, industrial wasted water contains many organic contaminants, and it is necessary to determine and monitor these contaminants. The paper first introduces Raman spectroscopy, and then describes its applications to determining the components in aqueous solutions, analyzes and assignes the Raman spectra of o-dichlorobenzene, o-xylene, m-xyiene and p-xylene in detail. The experimental results demonstrate that Raman spectroscopy is a particularly powerful technique for aqueous solutions analyses.

  6. Laser tweezers Raman spectroscopy of single cells

    NASA Astrophysics Data System (ADS)

    Chen, De

    Raman scattering is an inelastic collision between the vibrating molecules inside the sample and the incident photons. During this process, energy exchange takes place between the photon and the scattering molecule. By measuring the energy change of the photon, the molecular vibration mode can be probed. The vibrational spectrum contains valuable information about the disposition of atomic nuclei and chemical bonds within a molecule, the chemical compositions and the interactions between the molecule and its surroundings. In this dissertation, laser tweezers Raman spectroscopy (LTRS) technique is applied for the analysis of biological cells and human cells at single cell level. In LTRS, an individual cell is trapped in aqueous medium with laser tweezers, and Raman scattering spectra from the trapped cell are recorded in real-time. The Raman spectra of these cells can be used to reveal the dynamical processes of cell growth, cell response to environment changes, and can be used as the finger print for the identification of a bacterial cell species. Several biophysical experiments were carried out using LTRS: (1) the dynamic germination process of individual spores of Bacillus thuringiensis was detected via Ca-DPA, a spore-specific biomarker molecule; (2) inactivation and killing of Bacillus subtilis spores by microwave irradiation and wet heat were studied at single cell level; (3) the heat shock activation process of single B. subtilis spores were analyzed, in which the reversible transition from glass-like state at low temperature to liquid-like state at high temperature in spore was revealed at the molecular level; (4) the kinetic processes of bacterial cell lysis of E. coli by lysozyme and by temperature induction of lambda phage were detected real-time; (5) the fixation and rehydration of human platelets were quantitatively evaluated and characterized with Raman spectroscopy method, which provided a rapid way to quantify the quality of freeze-dried therapeutic

  7. Isolation and identification of bacteria by means of Raman spectroscopy.

    PubMed

    Pahlow, Susanne; Meisel, Susann; Cialla-May, Dana; Weber, Karina; Rösch, Petra; Popp, Jürgen

    2015-07-15

    Bacterial detection is a highly topical research area, because various fields of application will benefit from the progress being made. Consequently, new and innovative strategies which enable the investigation of complex samples, like body fluids or food stuff, and improvements regarding the limit of detection are of general interest. Within this review the prospects of Raman spectroscopy as a reliable tool for identifying bacteria in complex samples are discussed. The main emphasis of this work is on important aspects of applying Raman spectroscopy for the detection of bacteria like sample preparation and the identification process. Several approaches for a Raman compatible isolation of bacterial cells have been developed and applied to different matrices. Here, an overview of the limitations and possibilities of these methods is provided. Furthermore, the utilization of Raman spectroscopy for diagnostic purposes, food safety and environmental issues is discussed under a critical view. PMID:25895619

  8. Raman spectroscopy: the gateway into tomorrow's virology.

    PubMed

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-01-01

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology. PMID:16805914

  9. Raman spectroscopy: the gateway into tomorrow's virology

    PubMed Central

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-01-01

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology. PMID:16805914

  10. Study of virus by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Moor, K.; Kitamura, H.; Hashimoto, K.; Sawa, M.; Andriana, B. B.; Ohtani, K.; Yagura, T.; Sato, H.

    2013-02-01

    Problem of viruses is very actual for nowadays. Some viruses, which are responsible for human of all tumors, are about 15 %. Main purposes this study, early detection virus in live cell without labeling and in the real time by Raman spectroscopy. Micro Raman spectroscopy (mRs) is a technique that uses a Raman spectrometer to measure the spectra of microscopic samples. According to the Raman spectroscopy, it becomes possible to study the metabolites of a live cultured cell without labeling. We used mRs to detect the virus via HEK 293 cell line-infected adenovirus. We obtained raman specters of lives cells with viruses in 24 hours and 7 days after the infection. As the result, there is some biochemical changing after the treatment of cell with virus. One of biochemical alteration is at 1081 cm-1. For the clarification result, we use confocal fluorescent microscopy and transmission electron microscopy (TEM).

  11. Inverse Raman bands in ultrafast Raman loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Qiu, Xueqiong; Li, Xiuting; Niu, Kai; Lee, Soo-Y.

    2011-10-01

    Ultrafast Raman loss spectroscopy (URLS) is equivalent to anti-Stokes femtosecond stimulated Raman spectroscopy (FSRS), using a broadband probe pulse that extends to the blue of the narrow bandwidth Raman pump, and can be described as inverse Raman scattering (IRS). Using the Feynman dual time-line diagram, the third-order polarization for IRS with finite pulses can be written down in terms of a four-time correlation function. An analytic expression is obtained for the latter in the harmonic approximation which facilitates computation. We simulated the URLS of crystal violet (CV) for various resonance Raman pump excitation wavelengths using the IRS polarization expression with finite pulses. The calculated results agreed well with the experimental results of S. Umapathy et al., J. Chem. Phys. 133, 024505 (2010). In the limit of monochromatic Raman pump and probe pulses, we obtain the third-order susceptibility for multi-modes, and for a single mode we recover the well-known expression for the third-order susceptibility, χ _{IRS}^{(3)}, for IRS. The latter is used to understand the mode dependent phase changes as a function of Raman pump excitation in the URLS of CV.

  12. Emerging Dental Applications of Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Choo-Smith, Lin-P'ing; Hewko, Mark; Sowa, Michael G.

    Until recently, the application of Raman spectroscopy to investigate dental tissues has primarily focused on using microspectroscopy to characterize dentin and enamel structures as well as to understand the adhesive interface of various resin and bonding agents used in restorative procedures. With the advent of improved laser, imaging/mapping and fibre optic technologies, the applications have expanded to investigate various biomedical problems ranging from oral cancer, bacterial identification and early dental caries detection. The overall aim of these applications is to develop Raman spectroscopy into a tool for use in the dental clinic. This chapter presents the recent dental applications of Raman spectroscopy as well as discusses the potential, strengths and limitations of the technology in comparison with alternative techniques. In addition, a discussion and rationale about combining Raman spectroscopy with other optical techniques will be included.

  13. Micro-mirror arrays for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Duncan, W. M.

    2015-03-01

    In this research we study Raman and fluorescence spectroscopies as non-destructive and noninvasive methods for probing biological material and "living systems." Particularly for a living material any probe need be non-destructive and non-invasive, as well as provide real time measurement information and be cost effective to be generally useful. Over the past few years the components needed to measure weak and complex processes such as Raman scattering have evolved substantially with the ready availability of lasers, dichroic filters, low noise and sensitive detectors, digitizers and signal processors. A Raman spectrum consists of a wavelength or frequency spectrum that corresponds to the inelastic (Raman) photon signal that results from irradiating a "Raman active" material. Raman irradiation of a material usually and generally uses a single frequency laser. The Raman fingerprint spectrum that results from a Raman interaction can be determined from the frequencies scattered and received by an appropriate detector. Spectra are usually "digitized" and numerically matched to a reference sample or reference material spectra in performing an analysis. Fortunately today with the many "commercial off-the-shelf" components that are available, weak intensity effects such as Raman and fluorescence spectroscopy can be used for a number of analysis applications. One of the experimental limitations in Raman measurement is the spectrometer itself. The spectrometer is the section of the system that either by interference plus detection or by dispersion plus detection that "signal" amplitude versus energy/frequency signals are measured. Particularly in Raman spectroscopy, optical signals carrying desired "information" about the analyte are extraordinarily weak and require special considerations when measuring. We will discuss here the use of compact spectrometers and a micro-mirror array system (used is the digital micro-mirror device (DMD) supplied by the DLP® Products group of

  14. Occlusal caries detection using polarized Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ionita, I.; Bulou, A.

    2008-02-01

    The tooth enamel, because of its hydroxyapatite composition, must present a Raman spectrum with strong polarization anisotropy. Carious lesions of the enamel will produce an alteration of local symmetry and will increase much more scattering of light. This will reduce the anisotropy of the Raman spectra. Because of the difference between high sensitivity to polarization of the 959 cm -1 Raman peak in sound enamel and low sensitivity in carried enamel, Raman polarized spectroscopy could be a useful method to early detect teeth caries.

  15. Raman spectroscopy and polarization: Selected case studies

    NASA Astrophysics Data System (ADS)

    Ossikovski, Razvigor; Picardi, Gennaro; Ndong, Gérald; Chaigneau, Marc

    2012-10-01

    We show, through several selected case studies, the potential benefits that can be obtained by controlling the polarization states of the exciting and scattered radiations in a Raman scattering experiment. When coupled with polarization control, Raman spectroscopy is thus capable of providing extra information on the structural properties of the materials under investigation. The experimental examples presented in this work are taken from the area of both conventional, i.e., far-field, as well as from near-field Raman spectroscopy. They cover topics such as the stress tensor measurement in strained semiconductor structures, the vibration mode assignment in pentacene thin films and the Raman scattering tensor determination from near-field measurements on azobenzene monolayers. The basic theory necessary for modelling the far- and near-field polarized Raman responses is also given and the model efficiency is illustrated on the experimental data.

  16. Applications of Raman spectroscopy to gemology.

    PubMed

    Bersani, Danilo; Lottici, Pier Paolo

    2010-08-01

    Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals. PMID:20419294

  17. Difference Raman spectroscopy of DNA molecules

    NASA Astrophysics Data System (ADS)

    Anokhin, Andrey S.; Gorelik, Vladimir S.; Dovbeshko, Galina I.; Pyatyshev, Alexander Yu; Yuzyuk, Yury I.

    2015-01-01

    In this paper the micro-Raman spectra of calf DNA for different points of DNA sample have been recorded. The Raman spectra were made with help of difference Raman spectroscopy technique. Raman spectra were recorded with high spatial resolution from different points of the wet and dry samples in different spectral range (100÷4000cm-1) using two lasers: argon (514.5 nm) and helium -neon (632.8 nm). The significant differences in the Raman spectra for dry and wet DNA and for different points of DNA molecules were observed. The obtained data on difference Raman scattering spectra of DNA molecules may be used for identification of DNA types and for analysis of genetic information associated with the molecular structure of this molecule.

  18. Raman spectroscopy at the tritium laboratory Karlsruhe

    SciTech Connect

    Schloesser, M.; Bornschein, B.; Fischer, S.; Kassel, F.; Rupp, S.; Sturm, M.; James, T.M.; Telle, H.H.

    2015-03-15

    Raman spectroscopy is employed successfully for analysis of hydrogen isotopologues at the Tritium Laboratory Karlsruhe (TLK). Raman spectroscopy is based on the inelastic scattering of photons off molecules. Energy is transferred to the molecules as rotational/vibrational excitation being characteristic for each type of molecule. Thus, qualitative analysis is possible from the Raman shifted light, while quantitative information can be obtained from the signal intensities. After years of research and development, the technique is now well-advanced providing fast (< 10 s), precise (< 0.1%) and true (< 3%) compositional analysis of gas mixtures of hydrogen isotopologues. In this paper, we summarize the recent achievements in the further development on this technique, and the various applications for which it is used at TLK. Raman spectroscopy has evolved as a versatile, highly accurate key method for quantitative analysis complementing the port-folio of analytic techniques at the TLK.

  19. Mobile Raman spectroscopy in astrobiology research.

    PubMed

    Vandenabeele, Peter; Jehlička, Jan

    2014-12-13

    Raman spectroscopy has proved to be a very useful technique in astrobiology research. Especially, working with mobile instrumentation during fieldwork can provide useful experiences in this field. In this work, we provide an overview of some important aspects of this research and, apart from defining different types of mobile Raman spectrometers, we highlight different reasons for this research. These include gathering experience and testing of mobile instruments, the selection of target molecules and to develop optimal data processing techniques for the identification of the spectra. We also identify the analytical techniques that it would be most appropriate to combine with Raman spectroscopy to maximize the obtained information and the synergy that exists with Raman spectroscopy research in other research areas, such as archaeometry and forensics. PMID:25368355

  20. Using Raman spectroscopy to characterize biological materials.

    PubMed

    Butler, Holly J; Ashton, Lorna; Bird, Benjamin; Cinque, Gianfelice; Curtis, Kelly; Dorney, Jennifer; Esmonde-White, Karen; Fullwood, Nigel J; Gardner, Benjamin; Martin-Hirsch, Pierre L; Walsh, Michael J; McAinsh, Martin R; Stone, Nicholas; Martin, Francis L

    2016-04-01

    Raman spectroscopy can be used to measure the chemical composition of a sample, which can in turn be used to extract biological information. Many materials have characteristic Raman spectra, which means that Raman spectroscopy has proven to be an effective analytical approach in geology, semiconductor, materials and polymer science fields. The application of Raman spectroscopy and microscopy within biology is rapidly increasing because it can provide chemical and compositional information, but it does not typically suffer from interference from water molecules. Analysis does not conventionally require extensive sample preparation; biochemical and structural information can usually be obtained without labeling. In this protocol, we aim to standardize and bring together multiple experimental approaches from key leaders in the field for obtaining Raman spectra using a microspectrometer. As examples of the range of biological samples that can be analyzed, we provide instructions for acquiring Raman spectra, maps and images for fresh plant tissue, formalin-fixed and fresh frozen mammalian tissue, fixed cells and biofluids. We explore a robust approach for sample preparation, instrumentation, acquisition parameters and data processing. By using this approach, we expect that a typical Raman experiment can be performed by a nonspecialist user to generate high-quality data for biological materials analysis. PMID:26963630

  1. Raman spectroscopy of white wines.

    PubMed

    Martin, Coralie; Bruneel, Jean-Luc; Guyon, François; Médina, Bernard; Jourdes, Michael; Teissedre, Pierre-Louis; Guillaume, François

    2015-08-15

    The feasibility of exploiting Raman scattering to analyze white wines has been investigated using 3 different wavelengths of the incoming laser radiation in the near-UV (325 nm), visible (532 nm) and near infrared (785 nm). To help in the interpretation of the Raman spectra, the absorption properties in the UV-visible range of two wine samples as well as their laser induced fluorescence have also been investigated. Thanks to the strong intensity enhancement of the Raman scattered light due to electronic resonance with 325 nm laser excitation, hydroxycinnamic acids may be detected and analyzed selectively. Fructose and glucose may also be easily detected below ca. 1000 cm(-1). This feasibility study demonstrates the potential of the Raman spectroscopic technique for the analysis of white wines. PMID:25794745

  2. Emerging technology: applications of Raman spectroscopy for prostate cancer.

    PubMed

    Kast, Rachel E; Tucker, Stephanie C; Killian, Kevin; Trexler, Micaela; Honn, Kenneth V; Auner, Gregory W

    2014-09-01

    There is a need in prostate cancer diagnostics and research for a label-free imaging methodology that is nondestructive, rapid, objective, and uninfluenced by water. Raman spectroscopy provides a molecular signature, which can be scaled from micron-level regions of interest in cells to macroscopic areas of tissue. It can be used for applications ranging from in vivo or in vitro diagnostics to basic science laboratory testing. This work describes the fundamentals of Raman spectroscopy and complementary techniques including surface enhanced Raman scattering, resonance Raman spectroscopy, coherent anti-Stokes Raman spectroscopy, confocal Raman spectroscopy, stimulated Raman scattering, and spatially offset Raman spectroscopy. Clinical applications of Raman spectroscopy to prostate cancer will be discussed, including screening, biopsy, margin assessment, and monitoring of treatment efficacy. Laboratory applications including cell identification, culture monitoring, therapeutics development, and live imaging of cellular processes are discussed. Potential future avenues of research are described, with emphasis on multiplexing Raman spectroscopy with other modalities. PMID:24510129

  3. Anisotropic Raman Spectroscopy of Few-Layer Phosphorene

    NASA Astrophysics Data System (ADS)

    Du, Yuchen; Wu, Wangran; Maassen, Jesse; Luo, Zhe; Lundstrom, Mark; Xu, Xianfan; Ye, Peide

    Much recent research of black phosphorus (BP) and phosphorene has been focused on their unique anisotropy of this novel 2D material in terms of electrical, optical and thermal properties. Here we report the emerging Raman spectroscopy measurements of BP with respect to its isolation from bulk BP down to single layer phosphorene. The found frequency shift of BP in Raman spectra is to be correlated with atomic motion of modes, which can be explained by applying classical model of coupled harmonic oscillators. Raman intensity of different modes has also been included in our studies, which is confirmed as a solid strategy to quickly determine BP layer thickness. In addition, more information of their mechanical properties can also be obtained from Raman spectroscopy. The work was supported in part by NSF ECCS-1449270, NSF/AFOSR EFRI 2DARE Program, and ARO W911NF-15-1-0574.

  4. Airborne chemistry coupled to Raman spectroscopy.

    PubMed

    Santesson, Sabina; Johansson, Jonas; Taylor, Lynne S; Levander, Ia; Fox, Shannon; Sepaniak, Michael; Nilsson, Staffan

    2003-05-01

    In this paper, the use of airborne chemistry (acoustically levitated drops) in combination with Raman spectroscopy is explored. We report herein the first Raman studies of crystallization processes in levitated drops and the first demonstration of surface-enhanced Raman scattering (SERS) detection in this medium. Crystallization studies on the model compounds benzamide and indomethacin resulted in the formation of two crystal modifications for each compound, suggesting that this methodology may be useful for investigation of polymorphs. SERS detection resulted in a signal enhancement of 27 000 for benzoic acid and 11 000 for rhodamine 6-G. The preliminary results presented here clearly indicate that several important applications of the combination between Raman spectroscopy and acoustic drop levitation can be expected in the future. PMID:12720359

  5. Multiplex coherent raman spectroscopy detector and method

    NASA Technical Reports Server (NTRS)

    Chen, Peter (Inventor); Joyner, Candace C. (Inventor); Patrick, Sheena T. (Inventor); Guyer, Dean R. (Inventor)

    2004-01-01

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  6. Multiplex coherent raman spectroscopy detector and method

    DOEpatents

    Chen, Peter; Joyner, Candace C.; Patrick, Sheena T.; Guyer, Dean R.

    2004-06-08

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  7. Potential of Raman and Infrared Spectroscopy for Plant Analysis

    NASA Astrophysics Data System (ADS)

    Schulz, H.

    2008-11-01

    Various mid-infrared (MIR) and Raman spectroscopic methods applied to the analysis of valuable plant substances or quality parameters in selected horticultural and agricultural crops are presented. Generally, both spectroscopy techniques allow to identify simultaneously characteristic key bands of individual plant components (e.g. carotenoids, alkaloids, polyacetylenes, fatty acids, amino acids, terpenoids). In contrast to MIR methods Raman spectroscopy mostly does not need any sample pre-treatment; even fresh plant material can be analysed without difficulty because water shows only weak Raman scattering properties. In some cases a significant sensivity enhancement of Raman signals can be achieved if the exciting laser wavelength is adjusted to the absorption range of particular plant chromophores such as carotenoids (Resonance Raman effect). Applying FT-IR or FT Raman micro-spectroscopy the distribution of certain plant constituents in the cell wall can be identified without the need for any physical separation. Furthermore it is also possible to analyse secondary metabolites occurring in the cell vacuoles if significant key bands do not coincide with the spectral background of the plant matrix.

  8. Identification of gemstone treatments with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kiefert, Lore; Haenni, Henry A.; Chalain, Jean-Pierre

    2000-09-01

    The newest gemstone treatment concerns brownish diamonds of type IIa. These can be improved to near colorless by an enhancement process developed by General Electric, USA, using high temperature and pressure. A comparison of Raman spectroscopic features in the visible area (luminescence bands) of both treated and untreated colorless diamonds is given. Finally, examples of artificially colored peals and corals and their detection with Raman spectroscopy are shown.

  9. Raman spectroscopy under extreme conditions

    SciTech Connect

    Goncharov, A F; Crowhurst, J C

    2004-11-05

    We report the results of Raman measurements of various materials under simultaneous conditions of high temperature and high pressure in the diamond anvil cell (DAC). High temperatures are generated by laser heating or internal resistive (ohmic) heating or a combination of both. We present Raman spectra of cubic boron nitride (cBN) to 40 GPa and up to 2300 K that show a continuous pressure and temperature shift of the frequency of the transverse optical mode. We have also obtained high-pressure Raman spectra from a new noble metal nitride, which we synthesized at approximately 50 GPa and 2000 K. We have obtained high-temperature spectra from pure nitrogen to 39 GPa and up to 2000 K, which show the presence of a hot band that has previously been observed in CARS measurements. These measurements have also allowed us to constrain the melting curve and to examine changes in the intramolecular potential with pressure.

  10. Analysis of lipsticks using Raman spectroscopy.

    PubMed

    Gardner, P; Bertino, M F; Weimer, R; Hazelrigg, E

    2013-10-10

    In this study, 80 lipsticks were obtained and evaluated using Raman spectroscopy at excitation wavelengths of 532 and 780 nm. Fluorescence severely limited analysis with the 532 nm line while the 780 nm line proved useful for all samples analyzed. It was possible to differentiate 95% of the lipsticks evaluated based on one or more Raman peaks. However, there were no peak trends observed that could be used to identify a manufacturer or categorize a sample. In situ analysis of lipstick smears was found to be possible even from several Raman active substrates, but was occasionally limited by background fluorescence and in extreme cases, photodegradation. PMID:24053867

  11. Raman and multichannel Raman spectroscopy of biological systems

    NASA Astrophysics Data System (ADS)

    Bertoluzza, Alessandro; Caramazza, R.; Fagnano, C.

    1991-05-01

    Raman and multichannel Raman spectroscopy are molecular techniques able to monitor the bulk and surface structure of a biomaterial, in a non destructive and non invasive way, giving therefore useful information on physical and chemical aspects of biocompatibility. The same techniques can also be adequately used for the characterization of the biomaterial-host tissue interface, hence providing structural information on the biochemical aspect of biocompatibility. Moreover, multichannel Raman spectroscopy can also determine "in vivo" and "in situ" the bulk and surface structure of a biomaterial and the molecular interactions between biomaterials and tissues. Useful information at a molecular level on the biomaterial-tissue system can so be deduced. In particular, the application of traditional Paman spectroscopy to bioactive glasses (glasses derived from Hench's bioglass and meta and oligophosphates of calcium by themselves and with the addition of sodium and aluminium) useful in orthopedics and the application to hydrophobic (PMMA) and hydrophilic (PHEMA and PVP) organic polymers useful in ophthalmology are shown. Instead the applications of multichannel Paman spectroscopy are elucidated in the case of intraocular lenses (lOLs) based on PMMA and contact lenses (CLs) based on hydrophi I ic polymers.

  12. Coherent Raman spectroscopy for supersonic flow measurments

    NASA Technical Reports Server (NTRS)

    She, C. Y.

    1986-01-01

    In collaboration with NASA/Langley Research Center, a truly nonintrusive and nonseeding method for measuring supersonic molecular flow parameters was proposed and developed at Colorado State University. The feasibility of this Raman Doppler Velocimetry (RDV), currently operated in a scanning mode, was demonstrated not only in a laboratory environment at Colorado State University, but also in a major wind tunnel at NASA/Langley Research Center. The research progress of the RDV development is summarized. In addition, methods of coherent Rayleigh-Brillouin spectroscopy and single-pulse coherent Raman spectroscopy are investigated, respectively, for measurements of high-pressure and turbulent flows.

  13. Theory of femtosecond stimulated Raman spectroscopy.

    PubMed

    Lee, Soo-Y; Zhang, Donghui; McCamant, David W; Kukura, Philipp; Mathies, Richard A

    2004-08-22

    Femtosecond broadband stimulated Raman spectroscopy (FSRS) is a new technique that produces high-resolution (time-resolved) vibrational spectra from either the ground or excited electronic states of molecules, free from background fluorescence. FSRS uses simultaneously a narrow bandwidth approximately 1-3 ps Raman pump pulse with a continuum approximately 30-50 fs Stokes probe pulse to produce sharp Raman gains, at positions corresponding to vibrational transitions in the sample, riding on top of the continuum Stokes probe spectrum. When FSRS is preceded by a femtosecond actinic pump pulse that initiates the photochemistry of interest, time-resolved Raman spectroscopy can be carried out. We present two theoretical approaches to FSRS: one is based on a coupling of Raman pump and probe light waves with the vibrations in the medium, and another is a quantum-mechanical description. The latter approach is used to discuss the conditions of applicability and limitations of the coupled-wave description. Extension of the quantum-mechanical description to the case where the Raman pump beam is on resonance with an excited electronic state, as well as when FSRS is used to probe a nonstationary vibrational wave packet prepared by an actinic pump pulse, is also discussed. PMID:15303930

  14. High fidelity nanohole enhanced Raman spectroscopy.

    SciTech Connect

    Bahns, J. T.; Guo, Q.; Gray, S. K.; Jaeger, H. M.; Chen, L.; Montgomery, J. M.; Univ. of Chicago

    2009-01-01

    Surface enhanced Raman spectroscopy (SERS) is a sensitive technique that can even detect single molecules. However, in many SERS applications, the strongly inhomogeneous distribution of intense local fields makes it very difficult for a quantitive assessment of the fidelity, or reproducibility of the signal, which limits the application of SERS. Herein, we report the development of exceptionally high-fidelity hole-enhanced Raman spectroscopy (HERS) from ordered, 2D hexagonal nanohole arrays. We take the fidelity f to be a measure of the percent deviation of the Raman peaks from measurement to measurement. Overall, area averaged fidelities for 12 gold array samples ranged from f {approx} 2-15% for HERS using aqueous R6G molecules. Furthermore, intensity modulations of the enhanced Raman spectra were measured for the first time as a function of polarization angle. The best of these measurements, which focus on static laser spots on the sample, could be consistent with even higher fidelities than the area-averaged results. Nanohole arrays in silver provided supporting polarization measurements and a more complete enhanced Raman fingerprint for phenylalanine molecules. We also carried out finite-difference time-domain calculations to assist in the interpretation of the experiments, identifying the polarization dependence as possibly arising from hole-hole interactions. Our results represent a step toward making quantitative and reproducible enhanced Raman measurements possible and also open new avenues for a large-scale source of highly uniform hot spots.

  15. Endoscopic Raman Spectroscopy for Molecular Fingerprinting of Gastric Cancer: Principle to Implementation

    PubMed Central

    2015-01-01

    Currently, positive endoscopic biopsy is the standard criterion for gastric cancer diagnosis but is invasive, often inconsistent, and delayed although early detection and early treatment is the most important policy. Raman spectroscopy is a spectroscopic technique based on inelastic scattering of monochromatic light. Raman spectrum represents molecular composition of the interrogated volume providing a direct molecular fingerprint. Several investigations revealed that Raman spectroscopy can differentiate normal, dysplastic, and adenocarcinoma gastric tissue with high sensitivity and specificity. Moreover, this technique can indentify malignant ulcer and showed the capability to analyze the carcinogenesis process. Automated on-line Raman spectral diagnostic system raised possibility to use Raman spectroscopy in clinical field. Raman spectroscopy can be applied in many fields such as guiding a target biopsy, optical biopsy in bleeding prone situation, and delineating the margin of the lesion. With wide field technology, Raman spectroscopy is expected to have specific role in our future clinical field. PMID:26106612

  16. Disposable sheath that facilitates endoscopic Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Short, Michael; Tai, Isabella T.; Zeng, Haishan

    2016-02-01

    In vivo endoscopic Raman spectroscopy of human tissue using a fiber optic probe has been previously demonstrated. However, there remain several technical challenges, such as a robust control over the laser radiation dose and measurement repeatability during endoscopy. A decrease in the signal to noise was also observed due to aging of Raman probe after repeated cycles of harsh reprocessing procedures. To address these issues, we designed and tested a disposable, biocompatible, and sterile sheath for use with a fiber optic endoscopic Raman probe. The sheath effectively controls contamination of Raman probes between procedures, greatly reduces turnaround time, and slows down the aging of the Raman probes. A small optical window fitted at the sheath cap maintained the measurement distance between Raman probe end and tissue surface. To ensure that the sheath caused a minimal amount of fluorescence and Raman interference, the optical properties of materials for the sheath, optical window, and bonding agent were studied. The easy-to-use sheath can be manufactured at a moderate cost. The sheath strictly enforced a maximum permissible exposure standard of the tissue by the laser and reduced the spectral variability by 1.5 to 8.5 times within the spectral measurement range.

  17. Applications of high resolution inverse Raman spectroscopy

    SciTech Connect

    Owyoung, A.; Esherick, P.

    1980-01-01

    The use of high-power, narrow-band lasers has significantly improved the resolving power and sensitivity of inverse Raman spectroscopy of gases. In this paper we shall describe this technique, illustrate its capabilities by showing some Q-branch spectra of heavy spherical tops, and survey some possible future applications.

  18. Raman Spectroscopy Cell-based Biosensors

    PubMed Central

    Notingher, Ioan

    2007-01-01

    One of the main challenges faced by biodetection systems is the ability to detect and identify a large range of toxins at low concentrations and in short times. Cell-based biosensors rely on detecting changes in cell behaviour, metabolism, or induction of cell death following exposure of live cells to toxic agents. Raman spectroscopy is a powerful technique for studying cellular biochemistry. Different toxic chemicals have different effects on living cells and induce different time-dependent biochemical changes related to cell death mechanisms. Cellular changes start with membrane receptor signalling leading to cytoplasmic shrinkage and nuclear fragmentation. The potential advantage of Raman spectroscopy cell-based systems is that they are not engineered to respond specifically to a single toxic agent but are free to react to many biologically active compounds. Raman spectroscopy biosensors can also provide additional information from the time-dependent changes of cellular biochemistry. Since no cell labelling or staining is required, the specific time dependent biochemical changes in the living cells can be used for the identification and quantification of the toxic agents. Thus, detection of biochemical changes of cells by Raman spectroscopy could overcome the limitations of other biosensor techniques, with respect to detection and discrimination of a large range of toxic agents. Further developments of this technique may also include integration of cellular microarrays for high throughput in vitro toxicological testing of pharmaceuticals and in situ monitoring of the growth of engineered tissues.

  19. Raman Spectroscopy of Bone and Cartilage

    NASA Astrophysics Data System (ADS)

    Morris, Michael

    This chapter will reviews the Raman spectroscopy of the subject tissues. After a brief introduction to the structure, biology, and function of these tissues, we will describe the spectra and band assignments of the tissues and then summarize applications to studies of tissue development, mechanical function and competence, and pathology. Both metabolic diseases and genetic disorders will be covered.

  20. Raman spectroscopy of shocked water

    SciTech Connect

    Holmes, N.C.; Nellis, W.J.; Graham, W.B.; Walrafen, G.E.

    1985-08-01

    We describe a new technique for recording spontaneous Raman spectra from molecules during the passage of strong shock waves. We have used this technique to study the OH-stretch band of liquid H/sub 2/O shocked to pressure up to 26 GPa and 1700 K. The shape of the band changes over the range 7.5-26 GPa, and is described well by a two-component mixture model, implying changes in the intermolecular coupling of shock compressed water molecules. We discuss the implications of the spectra on the mechanism responsible for the electrical conductivity of shocked H/sub 2/O. 22 refs., 7 figs., 2 tabs.

  1. Raman spectroscopy of saliva as a perspective method for periodontitis diagnostics Raman spectroscopy of saliva

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Minaeva, S.

    2012-01-01

    In view of its potential for biological tissues analyses at a molecular level, Raman spectroscopy in optical range has been the object of biomedical research for the last years. The main aim of this work is the development of Raman spectroscopy for organic content identifying and determination of biomarkers of saliva at a molecular level for periodontitis diagnostics. Four spectral regions were determined: 1155 and 1525 cm-1, 1033 and 1611 cm-1, which can be used as biomarkers of this widespread disease.

  2. Detection Of Biochips By Raman And Surface Enhanced Raman Spectroscopies

    NASA Astrophysics Data System (ADS)

    Kantarovich, Keren; Tsarfati, Inbal; Gheber, Levi A.; Haupt, Karsten; Bar, Ilana

    2010-08-01

    Biochips constitute a rapidly increasing research field driven by the versatility of sensing devices and the importance of their applications in the bioanalytical field, drug development, environmental monitoring, food analysis, etc. Common strategies used for creating biochips and for reading them have extensive limitations, motivating development of miniature biochips and label-free formats. To achieve these goals we combined the nano fountain pen method, for printing microscale features with Raman spectroscopy or surface enhanced Raman spectroscopy (SERS) for reading droplets of synthetic receptors. These receptors include molecularly imprinted polymers (MIPs), which are obtained by polymerization of suitable functional and cross-linking monomers around molecular templates. MIPs are characterized by higher physical and chemical stability than biomacromolecules, and therefore are potentially very suitable as recognition elements for biosensors, or biochips. The monitored bands in the Raman and SERS spectra could be related to the taken up compound, allowing direct detection of the template, i.e., the β-blocking drug propranolol in the imprinted droplets, as well as imaging of individual and multiple dots in an array. This study shows that the combination of nanolithography techniques with SERS might open the possibility of miniaturized arrayed MIP sensors with label-free, specific and quantitative detection.

  3. Raman spectroscopy of Alzheimer's diseased tissue

    NASA Astrophysics Data System (ADS)

    Sudworth, Caroline D.; Krasner, Neville

    2004-07-01

    Alzheimer's disease is one of the most common forms of dementia, and causes steady memory loss and mental regression. It is also accompanied by severe atrophy of the brain. However, the pathological biomarkers of the disease can only be confirmed and examined upon the death of the patient. A commercial (Renishaw PLC, UK) Raman system with an 830 nm NIR diode laser was used to analyse brain samples, which were flash frozen at post-mortem. Ethical approval was sought for these samples. The Alzheimer's diseased samples contained a number of biomarkers, including neuritic plaques and tangles. The Raman spectra were examined by order to differentiate between normal and Alzheimer's diseased brain tissues. Preliminary results indicate that Alzheimer's diseased tissues can be differentiated from control tissues using Raman spectroscopy. The Raman spectra differ in terms of peak intensity, and the presence of a stronger amide I band in the 1667 cm-1 region which occurs more prominently in the Alzheimer's diseased tissue. These preliminary results indicate that the beta-amyloid protein originating from neuritic plaques can be identified with Raman spectroscopy.

  4. Monitoring lignocellulosic bioethanol production processes using Raman spectroscopy.

    PubMed

    Iversen, Jens A; Ahring, Birgitte K

    2014-11-01

    Process control automation in the emerging biorefinery industry may be achieved by applying effective methods for monitoring compound concentrations during the production processes. This study examines the application of Raman spectroscopy with an excitation wavelength of 785nm and an immersion probe for in situ monitoring the progression of pretreatment, hydrolysis and fermentation processes in the production of lignocellulosic ethanol. Raman signals were attenuated by light scattering cells and lignocellulosic particulates, which the quantification method to some degree could correct for by using an internal standard in the spectra. Allowing particulates to settle by using a slow stirring speed further improved results, suggesting that Raman spectroscopy should be used in combination with continuous separation when used to monitor process mixtures with large amounts of particulates. The root mean square error of prediction (RMSE) of ethanol and glucose measured in real-time was determined to be 0.98g/L and 1.91g/L respectively. PMID:25255187

  5. Raman spectroscopy of 'Bisphenol A'

    NASA Astrophysics Data System (ADS)

    Ullah, Ramzan; Zheng, Yuxiang

    2016-03-01

    Raman spectra (95 - 3000 cm-1) of 'Bisphenol A' are presented. Absorption peaks have been assigned by Density Functional Theory (DFT) with B3LYP 6 - 311 ++ G (3df, 3pd) and wB97XD 6 - 311 ++ G (3df, 3pd). B3LYP 6 - 311 ++ G (3df, 3pd) gives frequencies which are nearer to experimental frequencies than wB97XD 6 - 311 ++ G (3df, 3pd) which involves empirical dispersion. Scale factor for wB97XD 6 - 311 ++ G (3df, 3pd) is found out to be 0.95008 by least squares fit.

  6. Raman spectroscopy in head and neck cancer

    PubMed Central

    2010-01-01

    In recent years there has been much interest in the use of optical diagnostics in cancer detection. Early diagnosis of cancer affords early intervention and greatest chance of cure. Raman spectroscopy is based on the interaction of photons with the target material producing a highly detailed biochemical 'fingerprint' of the sample. It can be appreciated that such a sensitive biochemical detection system could confer diagnostic benefit in a clinical setting. Raman has been used successfully in key health areas such as cardiovascular diseases, and dental care but there is a paucity of literature on Raman spectroscopy in Head and Neck cancer. Following the introduction of health care targets for cancer, and with an ever-aging population the need for rapid cancer detection has never been greater. Raman spectroscopy could confer great patient benefit with early, rapid and accurate diagnosis. This technique is almost labour free without the need for sample preparation. It could reduce the need for whole pathological specimen examination, in theatre it could help to determine margin status, and finally peripheral blood diagnosis may be an achievable target. PMID:20923567

  7. Raman Spectroscopy of Soft Musculoskeletal Tissues

    PubMed Central

    Esmonde-White, Karen

    2015-01-01

    Tendon, ligament, and joint tissues are important in maintaining daily function. They can be affected by disease, age, and injury. Slow tissue turnover, hierarchical structure and function, and nonlinear mechanical properties present challenges to diagnosing and treating soft musculoskeletal tissues. Understanding these tissues in health, disease, and injury is important to improving pharmacologic and surgical repair outcomes. Raman spectroscopy is an important tool in the examination of soft musculoskeletal tissues. This article highlights exciting basic science and clinical/translational Raman studies of cartilage, tendon, and ligament. PMID:25286106

  8. Candida parapsilosis Biofilm Identification by Raman Spectroscopy

    PubMed Central

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-01-01

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made. PMID:25535081

  9. Candida parapsilosis biofilm identification by Raman spectroscopy.

    PubMed

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-01-01

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made. PMID:25535081

  10. Raman spectroscopy: Caution when interpreting organic carbon from oxidising environments

    NASA Astrophysics Data System (ADS)

    Brolly, Connor; Parnell, John; Bowden, Stephen

    2016-02-01

    Oxidation on Mars is primarily caused by the high influx of cosmic and solar radiation which interacts with the Martian surface. The evidence of this can be seen in the ubiquitous red colouration of the Martian sediment. This radiation will destroy most signals of life in the top few metres of the Martian surface. If organic carbon (one of the building blocks of life) is present within the accessible Martian sediments, it is very likely that it will have experienced some oxidation. ESA's ExoMars mission set to fly in 2018, has on board a miniaturised Raman spectrometer. As Raman spectroscopy is sensitive to carbonaceous material and will be primarily used to characterise organics, it is essential that the effect oxidation has on the Raman carbon signal is assessed. Oxidised carbonaceous shales were analysed using Raman spectroscopy to assess this issue. Results show that haematite has a band which occurs in the same frequency as the carbon D band, which cannot be distinguished from each other. This can lead to a misidentification of the carbon D band and a misinterpretation of the carbon order. Consequently, caution must be taken when applying Raman spectroscopy for organic carbon analysis in oxidised terrestrial and extraterrestrial environments, including on Mars.

  11. Two-dimensional low resolution Raman spectroscopy applied to fast discrimination of microorganisms that cause pharyngitis: A whole-organism fingerprinting approach

    NASA Astrophysics Data System (ADS)

    Mello, Cesar; Severi, Eza; Coelho, Lucinda; Marangoni, Antônio; Dezuane, Christiane; Ricci, Emiliane; Ribeiro, Diórginis; Poppi, Ronei Jesus

    2008-07-01

    The discrimination of the bacteria that cause pharyngitis through classical-microbiological methods is very efficient in the great majority of the cases. However, the high cost of chemicals and the time spent for such identifications, about four days, could generate serious consequences for the patients. Thus, the search for low cost spectroscopic methods which would allow a fast and reagentless discrimination of these microorganisms is extremely relevant. In this work, the main microorganisms that cause pharyngitis: S. aureus, S. pyogenes and Neisseria gonorrhoeae were studied. For each of the microorganisms 60 different dispersions were prepared using physiological solution as solvent and its Raman spectra were recorded. The 1D spectra obtained were similar, making it very difficult to differentiate the microorganisms. However, applying the 2D correlation method, it was possible to identify the microorganisms evaluated using the synchronous spectrum as "whole-organism fingerprinting" in a reduced time interval (˜10 h).

  12. Detection and Quantitative Analysis of Chemical Species in Hanford Tank Materials Using Raman Spectroscopy Technology: FY94Florida State University Raman Spectroscopy Report

    SciTech Connect

    Reich, F.R.

    1997-08-11

    This report provides a summary of work completed in FY-94 by FSU to develop and investigate the feasibility of using Raman spectroscopy with Hanford tank waste materials. Raman performance impacts from sample morphology, including the effects of absorption, particle size, density, color and refractive index, are discussed. An algorithm for relative species concentration measurement from Raman data is presented. An Algorithm for applying Raman to tank waste core screening is presented and discussed. A library of absorption and Raman spectra are presented that support this work.

  13. Remote adjustable focus Raman spectroscopy probe

    DOEpatents

    Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

    1999-01-01

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  14. Drug Stability Analysis by Raman Spectroscopy

    PubMed Central

    Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart

    2014-01-01

    Pharmaceutical drugs are available to astronauts to help them overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Here, we present a preliminary investigation of the ability of Raman spectroscopy to quantify mixtures of four drugs; acetaminophen, azithromycin, epinephrine, and lidocaine, with their primary degradation products. The Raman spectra for the mixtures were replicated by adding the pure spectra of the drug and its degradant to determine the relative percent contributions using classical least squares. This multivariate approach allowed determining concentrations in ~10 min with a limit of detection of ~4% of the degradant. These results suggest that a Raman analyzer could be used to assess drug potency, nondestructively, at the time of use to ensure crewmember safety. PMID:25533308

  15. Characterization of diatomaceous silica by Raman spectroscopy.

    PubMed

    Yuan, P; He, H P; Wu, D Q; Wang, D Q; Chen, L J

    2004-10-01

    The network characteristic of a selection of diatomaceous silica derived from China has been investigated using Raman spectroscopy. Before any thermal treatment of the sample, two prominent bands of 607 and circa 493 cm(-1) are resolved in the Raman spectra of diatomaceous silica, corresponding to the (SiO)3-ring breathing mode of D2-line and the O3SiOH tetrahedral vibration mode of D1-line, respectively. This is more similar to the pyrogenic silica rather than the silica gel. For the latter, to obtain a (SiO)3-ring, the sample must be heated between 250 and 450 degrees C. Significant difference is also found between the diatomaceous silica and other natural silicas, e.g. in the Raman spectra of sedimentary and volcanic opals, neither D1 nor D2 band is detected in previous reports. PMID:15350933

  16. Characterization of diatomaceous silica by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Yuan, P.; He, H. P.; Wu, D. Q.; Wang, D. Q.; Chen, L. J.

    2004-10-01

    The network characteristic of a selection of diatomaceous silica derived from China has been investigated using Raman spectroscopy. Before any thermal treatment of the sample, two prominent bands of 607 and circa 493 cm -1 are resolved in the Raman spectra of diatomaceous silica, corresponding to the (SiO) 3-ring breathing mode of D 2-line and the O 3SiOH tetrahedral vibration mode of D 1-line, respectively. This is more similar to the pyrogenic silica rather than the silica gel. For the latter, to obtain a (SiO) 3-ring, the sample must be heated between 250 and 450 °C. Significant difference is also found between the diatomaceous silica and other natural silicas, e.g. in the Raman spectra of sedimentary and volcanic opals, neither D 1 nor D 2 band is detected in previous reports.

  17. Drug stability analysis by Raman spectroscopy.

    PubMed

    Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart

    2014-01-01

    Pharmaceutical drugs are available to astronauts to help them overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Here, we present a preliminary investigation of the ability of Raman spectroscopy to quantify mixtures of four drugs; acetaminophen, azithromycin, epinephrine, and lidocaine, with their primary degradation products. The Raman spectra for the mixtures were replicated by adding the pure spectra of the drug and its degradant to determine the relative percent contributions using classical least squares. This multivariate approach allowed determining concentrations in ~10 min with a limit of detection of ~4% of the degradant. These results suggest that a Raman analyzer could be used to assess drug potency, nondestructively, at the time of use to ensure crewmember safety. PMID:25533308

  18. Detecting changes during pregnancy with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Vargis, Elizabeth; Robertson, Kesha; Al-Hendy, Ayman; Reese, Jeff; Mahadevan-Jansen, Anita

    2010-02-01

    Preterm labor is the second leading cause of neonatal mortality and leads to a myriad of complications like delayed development and cerebral palsy. Currently, there is no way to accurately predict preterm labor, making its prevention and treatment virtually impossible. While there are some at-risk patients, over half of all preterm births do not fall into any high-risk category. This study seeks to predict and prevent preterm labor by using Raman spectroscopy to detect changes in the cervix during pregnancy. Since Raman spectroscopy has been used to detect cancers in vivo in organs like the cervix and skin, it follows that spectra will change over the course of pregnancy. Previous studies have shown that fluorescence decreased during pregnancy and increased during post-partum exams to pre-pregnancy levels. We believe significant changes will occur in the Raman spectra obtained during the course of pregnancy. In this study, Raman spectra from the cervix of pregnant mice and women will be acquired. Specific changes that occur due to cervical softening or changes in hormonal levels will be observed to understand the likelihood that a female mouse or a woman will enter labor.

  19. Raman spectroscopy for analysis of thorium compounds

    NASA Astrophysics Data System (ADS)

    Su, Yin-Fong; Johnson, Timothy J.; Olsen, Khris B.

    2016-05-01

    The thorium fuel cycle is an alternative to the uranium fuel cycle in that when 232Th is irradiated with neutrons it is converted to 233U, another fissile isotope. There are several chemical forms of thorium which are used in the Th fuel cycle. Recently, Raman spectroscopy has become a very portable and facile analytical technique useful for many applications, including e.g. determining the chemical composition of different materials such as for thorium compounds. The technique continues to improve with the development of ever-more sensitive instrumentation and better software. Using a laboratory Fourier-transform (FT)-Raman spectrometer with a 785 nm wavelength laser, we were able to obtain Raman spectra from a series of thorium-bearing compounds of unknown origin. These spectra were compared to the spectra of in-stock-laboratory thorium compounds including e.g. ThO2, ThF4, Th(CO3)2 and Th(C2O4)2. The unknown spectra showed very good agreement to the known standards, demonstrating the applicability of Raman spectroscopy for detection and identification of these nuclear materials.

  20. Raman spectroscopy of ion-implanted silicon

    SciTech Connect

    Tuschel, D.D.; Lavine, J.P.

    1997-11-01

    Raman spectroscopy is used to characterize silicon implanted with boron at a dose of 10{sup 14}/cm{sup 2} or less and thermally annealed. The Raman scattering strengths and band shapes of the first-order optical mode at 520 cm{sup {minus}1} and of the second-order phonon modes are investigated to determine which modes are sensitive to the boron implant. The as-implanted samples show diminishing Raman scattering strength as the boron dose increases when the incident laser beam is 60{degree} with respect to the sample normal. Thermal annealing restores some of the Raman scattering strength. Three excitation wavelengths are used and the shortest, 457.9 nm, yields the greatest spectral differences from unimplanted silicon. The backscattering geometry shows a variety of changes in the Raman spectrum upon boron implantation. These involve band shifts of the first-order optical mode, bandwidth variations of the first-order optical mode, and the intensity of the second-order mode at 620 cm{sup {minus}1}.

  1. Toward improving fine needle aspiration cytology by applying Raman microspectroscopy

    NASA Astrophysics Data System (ADS)

    Becker-Putsche, Melanie; Bocklitz, Thomas; Clement, Joachim; Rösch, Petra; Popp, Jürgen

    2013-04-01

    Medical diagnosis of biopsies performed by fine needle aspiration has to be very reliable. Therefore, pathologists/cytologists need additional biochemical information on single cancer cells for an accurate diagnosis. Accordingly, we applied three different classification models for discriminating various features of six breast cancer cell lines by analyzing Raman microspectroscopic data. The statistical evaluations are implemented by linear discriminant analysis (LDA) and support vector machines (SVM). For the first model, a total of 61,580 Raman spectra from 110 single cells are discriminated at the cell-line level with an accuracy of 99.52% using an SVM. The LDA classification based on Raman data achieved an accuracy of 94.04% by discriminating cell lines by their origin (solid tumor versus pleural effusion). In the third model, Raman cell spectra are classified by their cancer subtypes. LDA results show an accuracy of 97.45% and specificities of 97.78%, 99.11%, and 98.97% for the subtypes basal-like, HER2+/ER-, and luminal, respectively. These subtypes are confirmed by gene expression patterns, which are important prognostic features in diagnosis. This work shows the applicability of Raman spectroscopy and statistical data handling in analyzing cancer-relevant biochemical information for advanced medical diagnosis on the single-cell level.

  2. Raman Spectroscopy of Irradiated Tissue Samples

    NASA Astrophysics Data System (ADS)

    Alexa, P.; Synytsya, A.; Volka, K.; de Boer, J.; Besserer, J.; Froschauer, S.; Loewe, M.; Moosburger, M.; Würkner, M.

    2003-06-01

    Tissue samples (skin of mice, normal and tumor, skin of a woman, normal and tumor) were irradiated by protons from the Munich tandem accelerator. The samples were analysed using Raman spectroscopy at the Institute of Chemical Technology in Prague by measuring the intensity of signals sensitive to radiation damage. Effects depending on the delivered dose were found. Proton-irradiation effects are then compared to those of gamma-irradiation.

  3. Raman and photothermal spectroscopies for explosive detection

    NASA Astrophysics Data System (ADS)

    Finot, Eric; Brulé, Thibault; Rai, Padmnabh; Griffart, Aurélien; Bouhélier, Alexandre; Thundat, Thomas

    2013-06-01

    Detection of explosive residues using portable devices for locating landmine and terrorist weapons must sat- isfy the application criteria of high reproducibility, specificity, sensitivity and fast response time. Vibrational spectroscopies such as Raman and infrared spectroscopies have demonstrated their potential to distinguish the members of the chemical family of more than 30 explosive materials. The characteristic chemical fingerprints in the spectra of these explosives stem from the unique bond structure of each compound. However, these spectroscopies, developed in the early sixties, suffer from a poor sensitivity. On the contrary, MEMS-based chemical sensors have shown to have very high sensitivity lowering the detection limit down to less than 1 picogram, (namely 10 part per trillion) using sensor platforms based on microcantilevers, plasmonics, or surface acoustic waves. The minimum amount of molecules that can be detected depends actually on the transducer size. The selectivity in MEMS sensors is usually realized using chemical modification of the active surface. However, the lack of sufficiently selective receptors that can be immobilized on MEMS sensors remains one of the most critical issues. Microcantilever based sensors offer an excellent opportunity to combine both the infrared photothermal spectroscopy in their static mode and the unique mass sensitivity in their dynamic mode. Optical sensors based on localized plasmon resonance can also take up the challenge of addressing the selectivity by monitoring the Surface Enhanced Raman spectrum down to few molecules. The operating conditions of these promising localized spectroscopies will be discussed in terms of reliability, compactness, data analysis and potential for mass deployment.

  4. The Impact of Array Detectors on Raman Spectroscopy

    ERIC Educational Resources Information Center

    Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner

    2007-01-01

    The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.

  5. Raman Spectroscopy: Incorporating the Chemical Dimension into Dermatological Diagnosis

    PubMed Central

    Sharma, Amit; Sharma, Shruti; Zarrow, Anna; Schwartz, Robert A; Lambert, W Clark

    2016-01-01

    Raman spectroscopy provides chemical analysis of tissue in vivo. By measuring the inelastic interactions of light with matter, Raman spectroscopy can determine the chemical composition of a sample. Diseases that are visually difficult to visually distinguish can be delineated based on differences in chemical composition of the affected tissue. Raman spectroscopy has successfully found spectroscopic signatures for skin cancers and differentiated those of benign skin growths. With current and on-going advances in optics and computing, inexpensive and effective Raman systems may soon be available for clinical use. Raman spectroscopy provides direct analyses of skin lesions, thereby improving both disease diagnosis and management. PMID:26955087

  6. [Laser Raman Spectroscopy and Its Application in Gas Hydrate Studies].

    PubMed

    Fu, Juan; Wu, Neng-you; Lu, Hai-long; Wu, Dai-dai; Su, Qiu-cheng

    2015-11-01

    Gas hydrates are important potential energy resources. Microstructural characterization of gas hydrate can provide information to study the mechanism of gas hydrate formation and to support the exploitation and application of gas hydrate technology. This article systemly introduces the basic principle of laser Raman spectroscopy and summarizes its application in gas hydrate studies. Based on Raman results, not only can the information about gas composition and structural type be deduced, but also the occupancies of large and small cages and even hydration number can be calculated from the relative intensities of Raman peaks. By using the in-situ analytical technology, laser Raman specstropy can be applied to characterize the formation and decomposition processes of gas hydrate at microscale, for example the enclathration and leaving of gas molecules into/from its cages, to monitor the changes in gas concentration and gas solubility during hydrate formation and decomposition, and to identify phase changes in the study system. Laser Raman in-situ analytical technology has also been used in determination of hydrate structure and understanding its changing process under the conditions of ultra high pressure. Deep-sea in-situ Raman spectrometer can be employed for the in-situ analysis of the structures of natural gas hydrate and their formation environment. Raman imaging technology can be applied to specify the characteristics of crystallization and gas distribution over hydrate surface. With the development of laser Raman technology and its combination with other instruments, it will become more powerful and play a more significant role in the microscopic study of gas hydrate. PMID:26978895

  7. Distinguishing Cancerous Liver Cells Using Surface-Enhanced Raman Spectroscopy.

    PubMed

    Huang, Jing; Liu, Shupeng; Chen, Zhenyi; Chen, Na; Pang, Fufei; Wang, Tingyun

    2016-02-01

    Raman spectroscopy has been widely used in biomedical research and clinical diagnostics. It possesses great potential for the analysis of biochemical processes in cell studies. In this article, the surface-enhanced Raman spectroscopy (SERS) of normal and cancerous liver cells incubated with SERS active substrates (gold nanoparticle) was measured using confocal Raman microspectroscopy technology. The chemical components of the cells were analyzed through statistical methods for the SERS spectrum. Both the relative intensity ratio and principal component analysis (PCA) were used for distinguishing the normal liver cells (QSG-7701) from the hepatoma cells (SMMC-7721). The relative intensity ratio of the Raman spectra peaks such as I937/I1209, I1276/I1308, I1342/I1375, and I1402/I1435 was set as the judge boundary, and the sensitivity and the specificity using PCA method were calculated. The results indicated that the surface-enhanced Raman spectrum could provide the chemical information for distinguishing the normal cells from the cancerous liver cells and demonstrated that SERS technology possessed the possible applied potential for the diagnosis of liver cancer. PMID:25432931

  8. Standoff detection of explosive molecules using nanosecond gated Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chung, Jin Hyuk; Cho, Soo Gyeong

    2013-06-01

    Recently, improvised explosive device (IED) has been a serious threat for many countries. One of the approaches to alleviate this threat is standoff detection of explosive molecules used in IEDs. Raman spectroscopy is a prospective method among many technologies under research to achieve this goal. It provides unique information of the target materials, through which the ingredients used in IEDs can be analyzed and identified. The main problem of standoff Raman spectroscopic detection is the large background noise hindering weak Raman signals from the target samples. Typical background noise comes from both ambient fluorescent lights indoor and sunlight outdoor whose intensities are usually much larger than that of Raman scattering from the sample. Under the proper condition using pulse laser and ICCD camera with nanosecond pulse width and gating technology, we succeed to separate and remove these background noises from Raman signals. For this experiment, we build an optical system for standoff detection of explosive molecules. We use 532 nm, 10 Hz, Q-switching Nd:YAG laser as light source, and ICCD camera triggered by laser Qswitching time with proper gate delay regarding the flight time of Raman from target materials. Our detection system is successfully applied to detect and identify more than 20 ingredients of IEDs including TNT, RDX, and HMX which are located 10 to 54 meters away from the system.

  9. [Raman spectroscopy applied to analytical quality control of injectable drugs: analytical evaluation and comparative economic versus HPLC and UV / visible-FTIR].

    PubMed

    Bourget, P; Amin, A; Vidal, F; Merlette, C; Troude, P; Corriol, O

    2013-09-01

    In France, central IV admixture of chemotherapy (CT) treatments at the hospital is now required by law. We have previously shown that the shaping of Therapeutic Objects (TOs) could profit from an Analytical Quality Assurance (AQA), closely linked to the batch release, for the three key parameters: identity, purity, and initial concentration of the compound of interest. In the course of recent and diversified works, we showed the technical superiority of non-intrusive Raman Spectroscopy (RS) vs. any other analytical option and, especially for both HPLC and vibrational method using a UV/visible-FTIR coupling. An interconnected qualitative and economic assessment strongly helps to enrich these relevant works. The study compares in operational situation, the performance of three analytical methods used for the AQC of TOs. We used: a) a set of evaluation criteria, b) the depreciation tables of the machinery, c) the cost of disposables, d) the weight of equipment and technical installations, e) the basic accounting unit (unit of work) and its composite costs (Euros), which vary according to the technical options, the weight of both human resources and disposables; finally, different combinations are described. So, the unit of work can take 12 different values between 1 and 5.5 Euros, and we provide various recommendations. A qualitative evaluation grid constantly places the SR technology as superior or equal to the 2 other techniques currently available. Our results demonstrated: a) the major interest of the non-intrusive AQC performed by RS, especially when it is not possible to analyze a TO with existing methods e.g. elastomeric portable pumps, and b) the high potential for this technique to be a strong contributor to the security of the medication circuit, and to fight the iatrogenic effects of drugs especially in the hospital. It also contributes to the protection of all actors in healthcare and of their working environment. PMID:24804411

  10. Raman spectroscopy of C-irradiated graphite

    SciTech Connect

    Hembree, D.M. Jr.; Pedraza, D.F.; Romanoski, G.R.; Withrow, S.P.; Annis, B.K.

    1994-09-01

    Highly oriented pyrolytic graphite samples were irradiated with C{sup +} ions at 35 keV in a direction normal to the basal plane and subsequently annealed up to 1373 K. Substantial surface topography changes were observed at fluences of 5 {times} 10{sup 18} ions/m{sup 2} and higher using scanning electron and atomic force microscopies. Intricate networks of surface cracks and ridges developed after high dose implantation. A systematic study of the irradiation effects was conducted using Raman spectroscopy. Microstructural changes in irradiated regions were first detected at a dose of 1 {times} 10{sup 17} ions/m{sup 2} through the appearance of the Raman D-line at {approx}1360 cm{sup {minus}1}. The intensity of this line increases while that of the Raman G-line at 1580 cm{sup {minus}1} decreases as the irradiation dose is increased or the irradiation temperature is decreased. After irradiation at 280K to a fluence of 5 {times} 10{sup 19} ions/m{sup 2} or higher the first order spectrum exhibits one single line at a wavelength intermediate between the D- and G-lines. Damage recovery upon thermal annealing depends not only on the initial damage state but also on the annealing temperature sequence. Samples irradiated to a damage level where two distinct Raman peaks are no longer resolvable exhibited upon direct annealing at a high temperature two distinct Raman lines. By contrast, pre-annealing these highly irradiated specimens at lower temperatures produced less pronounced changes in the Raman spectra. Pre-annealing appears to stabilize damage structures that are more resistant to high-temperature annealing than those induced by irradiation.

  11. Raman spectroscopy for cytopathology of exfoliated cervical cells.

    PubMed

    Ramos, I R; Meade, A D; Ibrahim, O; Byrne, H J; McMenamin, M; McKenna, M; Malkin, A; Lyng, F M

    2016-06-23

    Cervical cancer is the fourth most common cancer affecting women worldwide but mortality can be decreased by early detection of pre-malignant lesions. The Pap smear test is the most commonly used method in cervical cancer screening programmes. Although specificity is high for this test, it is widely acknowledged that sensitivity can be poor mainly due to the subjective nature of the test. There is a need for new objective tests for the early detection of pre-malignant cervical lesions. Over the past two decades, Raman spectroscopy has emerged as a promising new technology for cancer screening and diagnosis. The aim of this study was to evaluate the potential of Raman spectroscopy for cervical cancer screening using both Cervical Intraepithelial Neoplasia (CIN) and Squamous Intraepithelial Lesion (SIL) classification terminology. ThinPrep® Pap samples were recruited from a cervical screening population. Raman spectra were recorded from single cell nuclei and subjected to multivariate statistical analysis. Normal and abnormal ThinPrep® samples were discriminated based on the biochemical fingerprint of the cells using Principal Component Analysis (PCA). Principal Component Analysis - Linear Discriminant Analysis (PCA-LDA) was employed to build classification models based on either CIN or SIL terminology. This study has shown that Raman spectroscopy can be successfully applied to the study of routine cervical cytology samples from a cervical screening programme and that the use of CIN terminology resulted in improved sensitivity for high grade cases. PMID:27032537

  12. Raman spectroscopy for diagnosis of glioblastoma multiforme

    NASA Astrophysics Data System (ADS)

    Clary, Candace Elise

    Glioblastoma multiforme (GBM), the most common and most fatal malignant brain tumor, is highly infiltrative and incurable. Although improved prognosis has been demonstrated by surgically resecting the bulk tumor, a lack of clear borders at the tumor margins complicates the selection decision during surgery. This dissertation investigates the potential of Raman spectroscopy for distinguishing between normal and malignant brain tissue and sets the groundwork for a surgical diagnostic guide for resection of gross malignant gliomas. These studies revealed that Raman spectroscopy was capable of discriminating between normal scid mouse brain tissue and human xenograft tumors induced in those mice. The spectra of normal and malignant tissue were normalized by dividing by the respective magnitudes of the peaks near 1440 cm -1. Spectral differences include the shape of the broad peaks near 1440 cm-1 and 1660 cm-1 and the relative magnitudes of the peaks at 1264 cm-1, 1287 cm-1, 1297 cm-1, 1556 cm -1, 1586 cm-1, 1614 cm-1, and 1683 cm-1. From these studies emerged questions regarding how to objectively normalize and compare spectra for future automation. Some differences in the Raman spectra were shown to be inherent in the disease states of the cells themselves via differences in the Raman spectra of normal human astrocytes in culture and cultured cells derived from GBM tumors. The spectra of astrocytes and glioma cells were normalized by dividing by the respective magnitudes of the peaks near 1450 cm-1. The differences between the Raman spectra of normal and transformed cells include the ratio of the 1450 cm-1/1650 cm-1 peaks and the relative magnitudes of the peaks at 1181 cm-1, 1191 cm-1, 1225 cm-1, 1263 cm -1, 1300 cm-1, 1336 cm-1, 1477 cm-1, 1494 cm-1, and 1695 cm -1. Previous Raman spectroscopic studies of biological cells have shown that the magnitude of the Raman signal decreases over time, indicating sample damage. Cells exposed to laser excitation at similar power

  13. Electronic resonances in broadband stimulated Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Batignani, G.; Pontecorvo, E.; Giovannetti, G.; Ferrante, C.; Fumero, G.; Scopigno, T.

    2016-01-01

    Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process.

  14. Electronic resonances in broadband stimulated Raman spectroscopy

    PubMed Central

    Batignani, G.; Pontecorvo, E.; Giovannetti, G.; Ferrante, C.; Fumero, G.; Scopigno, T.

    2016-01-01

    Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process. PMID:26728791

  15. Spectral variable selection for partial least squares calibration applied to authentication and quantification of extra virgin olive oils using Fourier transform Raman spectroscopy.

    PubMed

    Heise, H Michael; Damm, Uwe; Lampen, Peter; Davies, Antony N; McIntyre, Peter S

    2005-10-01

    The limits of quantitative multivariate assays for the analysis of extra virgin olive oil samples from various Greek sites adulterated by sunflower oil have been evaluated based on their Fourier transform (FT) Raman spectra. Different strategies for wavelength selection were tested for calculating optimal partial least squares (PLS) models. Compared to the full spectrum methods previously applied, the optimum standard error of prediction (SEP) for the sunflower oil concentrations in spiked olive oil samples could be significantly reduced. One efficient approach (PMMS, pair-wise minima and maxima selection) used a special variable selection strategy based on a pair-wise consideration of significant respective minima and maxima of PLS regression vectors, calculated for broad spectral intervals and a low number of PLS factors. PMMS provided robust calibration models with a small number of variables. On the other hand, the Tabu search strategy recently published (search process guided by restrictions leading to Tabu list) achieved lower SEP values but at the cost of extensive computing time when searching for a global minimum and less robust calibration models. Robustness was tested by using packages of ten and twenty randomly selected samples within cross-validation for calculating independent prediction values. The best SEP values for a one year's harvest with a total number of 66 Cretian samples were obtained by such spectral variable optimized PLS calibration models using leave-20-out cross-validation (values between 0.5 and 0.7% by weight). For the more complex population of olive oil samples from all over Greece (total number of 92 samples), results were between 0.7 and 0.9% by weight with a cross-validation sample package size of 20. Notably, the calibration method with Tabu variable selection has been shown to be a valid chemometric approach by which a single model can be applied with a low SEP of 1.4% for olive oil samples across three different harvest years

  16. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    PubMed Central

    Shih, Wei-Chuan; Bechtel, Kate L.; Rebec, Mihailo V.

    2015-01-01

    Abstract. We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ∼1.5−2  mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies. PMID:25688542

  17. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shih, Wei-Chuan; Bechtel, Kate L.; Rebec, Mihailo V.

    2015-05-01

    We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ˜1.5-2 mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies.

  18. Composition of Uranium Oxide Surface Layers Analyzed by m-Raman Spectroscopy

    SciTech Connect

    Siekhaus, W J

    2003-11-24

    Oxide thickness and composition averaged over a few square millimeter has been measured with nm thickness resolution by diffuse reflectance fourier transform infrared (FTIR) spectroscopy. {mu}-Raman spectroscopy has been done on powders and bulk samples in the past, and can now be done on surfaces layers with {micro}m lateral and depth resolution using con-focal microscopy. Here we apply con-focal-microscopy-based {mu}-Raman spectroscopy to a freshly polished/lightly oxidized and to heavily oxidized uranium to determine its sensitivity. The spectra show that {mu}-Raman spectroscopy does detect oxide thickness and oxide composition with high sensitivity.

  19. Surface-enhanced Raman spectroscopy of pterins

    NASA Astrophysics Data System (ADS)

    Smyth, Ciarán A.; Mirza, Inam; Lunney, James G.; McCabe, Eithne M.

    2012-03-01

    Raman spectroscopy is a useful technique in the identification and characterisation of compounds, but in terms of sensitivity its application is limited. With respect to this the discovery of the surface-enhanced Raman scattering (SERS) phenomenon has proved monumental, and much research has been carried out over the past 30 years developing the technique. Pterins are biological compounds that are found in nature in colour pigmentation and in mammalian metabolic pathways. Moreover, they have been identified in abnormal concentrations in cancer patients, suggesting potential applications in cancer diagnostics. SERS is an ideal technique to identify these compounds, and both nanoparticle suspensions and pulsed laser deposited nanoparticle substrates have been used to examine the spectra of xanthopterin, both in aqueous solution and in different pH environments.

  20. Lignin analysis by FT-Raman spectroscopy

    SciTech Connect

    Agarwal, U.P.; Obst, J.R.; Cannon, A.B.

    1996-10-01

    Traditional methods of lignin analysis, such as Klason (acid insoluble) lignin determinations, give satisfactory results, are widely accepted, and often are considered as standard analyses. However, the Klason lignin method is laborious and time consuming; it also requires a fairly large-amount of isolated analyte. FT-Raman spectroscopy offers an opportunity to simplify and speed up lignin analyses. FT-Raman data for a number of hardwoods (angiosperms) and softwoods (gymnosperms) are compared with data obtained using other analytical methods, including Klason lignin (with corrections for acid soluble lignin), acetyl bromide, and FT-IR determinations. In addition, 10 different specimens of Nothofagus dombeyii (chosen because of the widely varying syringyl:guaiacyl monomer compositions of their lignins) were also analyzed. Lignin monomer compositions were determined by thioacidolysis of by nitrobenzene oxidation.

  1. Simultaneous Conoscopic Holography and Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F.; Kaiser, Bruce

    2005-01-01

    A new instrument was developed for chemical characterization of surfaces that combines the analytical power of Raman spectroscopy with the three-dimensional topographic information provided by conoscopic holography. The figure schematically depicts the proposed hybrid instrument. The output of the conoscopic holographic portion of the instrument is a topographical map of the surface; the output of the Raman portion of the instrument is hyperspectral Raman data, from which the chemical and/or biological composition of the surface would be deduced. By virtue of the basic principles of design and operation of the instrument, the hyperspectral image data would be inherently spatially registered with the topographical data. In conoscopic holography, the object and reference beams of classical holography are replaced by the ordinary and extraordinary components generated by a single beam traveling through a birefringent, uniaxial crystal. In the basic conoscopic configuration, a laser light is projected onto a specimen and the resulting illuminated spot becomes a point source of diffuse light that propagates in every direction. The laser beam is rasterscanned in two dimensions (x and y) perpendicular to the beam axis (z), and at each x,y location, the pattern of interference between the ordinary and extraordinary rays is recorded. The recorded interferogram constitutes the conoscopic hologram. Of particular significance for the proposed instrument is that the conoscopic hologram contains information on the z coordinate (height) of the illuminated surface spot. Hence, a topographical map of the specimen is constructed point-by-point by rastering the laser beam in the x and y directions and correlating the x and y coordinates with the z information obtained from the interferograms. Conoscopic imaging is an established method, and conoscopic laboratory instruments for surface metrology are commercially available. In Raman spectroscopy of a surface, one measures the spectrum

  2. Characterization of Thalidomide using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cipriani, Penelope; Smith, Candace Y.

    2008-02-01

    Thalidomide is a potent anticancer therapeutic drug whose mechanism of action has not yet been elucidated. In this report, experimental Raman spectroscopy is used to determine and characterize the vibrational frequencies of the drug. These normal modes are then compared to their quantum mechanical counterparts, which have been computed using density functional theory. Upon analysis of the spectra, we found that there was a high level of agreement between the wavenumbers. As such, this spectroscopic technique may be a viable tool for examining the way in which this drug interacts with its target molecules.

  3. Raman spectroscopy of ball-milled TiO 2

    NASA Astrophysics Data System (ADS)

    Gajović, A.; Stubičar, M.; Ivanda, M.; Furić, K.

    2001-05-01

    Raman spectroscopy was applied to study structural and dimensional changes during high-energy ball milling of TiO 2 anatase. Milling was performed for up to 10 h using two different sets of grinding tools (wolfram carbide (WC) and agate). The diminution of the TiO 2 particle to nanometric size was monitoring by low-frequency Raman spectroscopy. The nanometric sizes were confirmed by transmission electron microscopy (TEM). After short milling time by WC the bands of high-pressure TiO 2 II phase (α-PbO 2 structure) were detected in Raman spectrum. Prolonged milling time was needed for transformation to rutil. When milling was performed by agate, the time necessary for both phase transitions was longer, presumably because of lower ball-to-powder weight ratio. The low-frequency Raman band of the prolonged milled samples was broad, which suggests the wide dispersion in nano-particle dimensions. The position of the low-frequency band in longer-milled samples indicated dimensions smaller than 20 nm, since the diameter of the particle is inversely proportional to the low-frequency mode of the spherical particles. These results were in agreement with the TEM results.

  4. Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

    PubMed Central

    Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

    2016-01-01

    Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

  5. UTI diagnosis and antibiogram using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kastanos, Evdokia; Kyriakides, Alexandros; Hadjigeorgiou, Katerina; Pitris, Constantinos

    2009-07-01

    Urinary tract infection diagnosis and antibiogram require a 48 hour waiting period using conventional methods. This results in ineffective treatments, increased costs and most importantly in increased resistance to antibiotics. In this work, a novel method for classifying bacteria and determining their sensitivity to an antibiotic using Raman spectroscopy is described. Raman spectra of three species of gram negative Enterobacteria, most commonly responsible for urinary tract infections, were collected. The study included 25 samples each of E.coli, Klebsiella p. and Proteus spp. A novel algorithm based on spectral ratios followed by discriminant analysis resulted in classification with over 94% accuracy. Sensitivity and specificity for the three types of bacteria ranged from 88-100%. For the development of an antibiogram, bacterial samples were treated with the antibiotic ciprofloxacin to which they were all sensitive. Sensitivity to the antibiotic was evident after analysis of the Raman signatures of bacteria treated or not treated with this antibiotic as early as two hours after exposure. This technique can lead to the development of new technology for urinary tract infection diagnosis and antibiogram with same day results, bypassing urine cultures and avoiding all undesirable consequences of current practice.

  6. Disease recognition by infrared and Raman spectroscopy.

    PubMed

    Krafft, Christoph; Steiner, Gerald; Beleites, Claudia; Salzer, Reiner

    2009-02-01

    Infrared (IR) and Raman spectroscopy are emerging biophotonic tools to recognize various diseases. The current review gives an overview of the experimental techniques, data-classification algorithms and applications to assess soft tissues, hard tissues and body fluids. The methodology section presents the principles to combine vibrational spectroscopy with microscopy, lateral information and fiber-optic probes. A crucial step is the classification of spectral data by a variety of algorithms. We discuss unsupervised algorithms such as cluster analysis or principal component analysis and supervised algorithms such as linear discriminant analysis, soft independent modeling of class analogies, artificial neural networks support vector machines, Bayesian classification, partial least-squares regression and ensemble methods. The selected topics include tumors of epithelial tissue, brain tumors, prion diseases, bone diseases, atherosclerosis, kidney stones and gallstones, skin tumors, diabetes and osteoarthritis. PMID:19343682

  7. Coronagraphic Notch Filter for Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Cohen, David; Stirbl, Robert

    2004-01-01

    A modified coronagraph has been proposed as a prototype of improved notch filters in Raman spectrometers. Coronagraphic notch filters could offer alternatives to both (1) the large and expensive double or triple monochromators in older Raman spectrometers and (2) holographic notch filters, which are less expensive but are subject to environmental degradation as well as to limitations of geometry and spectral range. Measurement of a Raman spectrum is an exercise in measuring and resolving faint spectral lines close to a bright peak: In Raman spectroscopy, a monochromatic beam of light (the pump beam) excites a sample of material that one seeks to analyze. The pump beam generates a small flux of scattered light at wavelengths slightly greater than that of the pump beam. The shift in wavelength of the scattered light from the pump wavelength is known in the art as the Stokes shift. Typically, the flux of scattered light is of the order of 10 7 that of the pump beam and the Stokes shift lies in the wave-number range of 100 to 3,000 cm 1. A notch filter can be used to suppress the pump-beam spectral peak while passing the nearby faint Raman spectral lines. The basic principles of design and operation of a coronagraph offer an opportunity for engineering the spectral transmittance of the optics in a Raman spectrometer. A classical coronagraph may be understood as two imaging systems placed end to end, such that the first system forms an intermediate real image of a nominally infinitely distant object and the second system forms a final real image of the intermediate real image. If the light incident on the first telescope is collimated, then the intermediate image is a point-spread function (PSF). If an appropriately tailored occulting spot (e.g., a Gaussian-apodized spot with maximum absorption on axis) is placed on the intermediate image plane, then the instrument inhibits transmission of light from an on-axis source. However, the PSFs of off-axis light sources are

  8. Probing nanoscale ferroelectricity by ultraviolet Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tenne, Dmitri

    2007-03-01

    Conventional vibrational spectroscopies operating in visible and infrared range fail to measure the phonon spectra of nanoscale ferroelectric structures because of extremely weak signals and the overwhelming substrate contribution. In this talk, application of ultraviolet (UV) Raman spectroscopy for studies of lattice dynamics and ferroelectric phase transitions in nanoscale ferroelectrics will be presented. We demonstrate that UV Raman spectroscopy is an effective technique allowing the observation of phonons and determination of the ferroelectric phase transition temperature (Tc) in nanoscale ferroelectrics, specifically, BaTiO3/SrTiO3 superlattices having the ferroelectric BaTiO3 layers as thin as 1 unit cell, and single BaTiO3 layers as thin as 4 nm. BaTiO3/SrTiO3 superlattices and ultrathin BaTiO3 films studied were grown by molecular beam epitaxy on SrTiO3 as well as GdScO3 and DyScO3 substrates. Excellent epitaxial quality and atomically abrupt interfaces are evidenced by X-ray diffraction and high resolution transmission electron microscopy. UV Raman results show that one-unit-cell thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are ferroelectric with the Tc as high as 250 K, and induce the polarization in much thicker SrTiO3 layers adjacent to them. The Tc in superlattices was tuned by hundreds of degrees from ˜170 to 650 K by varying the thicknesses of BaTiO3 and SrTiO3 layers. Using scandate substrates enables growth of superlattices with systematically changed coherent strain, thus allowing studying the stress effect on the ferroelectric phase transitions. UV Raman data are supported by the thermodynamic calculations of polarization in superlattices as a function of temperature. The work was done in collaboration with A. Soukiassian, W. Tian, D.G. Schlom, Y.L. Li, L.-Q. Chen, X.X. Xi (Pennsylvania State University), A. Bruchhausen, A. Fainstein (Centro Atomico Bariloche & Instituto Balseiro, Argentina), R. S. Katiyar (University of Puerto Rico), A

  9. In vivo Raman spectroscopy of cervix cancers

    NASA Astrophysics Data System (ADS)

    Rubina, S.; Sathe, Priyanka; Dora, Tapas Kumar; Chopra, Supriya; Maheshwari, Amita; Krishna, C. Murali

    2014-03-01

    Cervix-cancer is the third most common female cancer worldwide. It is the leading cancer among Indian females with more than million new diagnosed cases and 50% mortality, annually. The high mortality rates can be attributed to late diagnosis. Efficacy of Raman spectroscopy in classification of normal and pathological conditions in cervix cancers on diverse populations has already been demonstrated. Our earlier ex vivo studies have shown the feasibility of classifying normal and cancer cervix tissues as well as responders/non-responders to Concurrent chemoradiotherapy (CCRT). The present study was carried out to explore feasibility of in vivo Raman spectroscopic methods in classifying normal and cancerous conditions in Indian population. A total of 182 normal and 132 tumor in vivo Raman spectra, from 63 subjects, were recorded using a fiberoptic probe coupled HE-785 spectrometer, under clinical supervision. Spectra were acquired for 5 s and averaged over 3 times at 80 mW laser power. Spectra of normal conditions suggest strong collagenous features and abundance of non-collagenous proteins and DNA in case of tumors. Preprocessed spectra were subjected to Principal Component-Linear Discrimination Analysis (PCLDA) followed by leave-one-out-cross-validation. Classification efficiency of ~96.7% and 100% for normal and cancerous conditions respectively, were observed. Findings of the study corroborates earlier studies and suggest applicability of Raman spectroscopic methods in combination with appropriate multivariate tool for objective, noninvasive and rapid diagnosis of cervical cancers in Indian population. In view of encouraging results, extensive validation studies will be undertaken to confirm the findings.

  10. Controlling protected designation of origin of wine by Raman spectroscopy.

    PubMed

    Mandrile, Luisa; Zeppa, Giuseppe; Giovannozzi, Andrea Mario; Rossi, Andrea Mario

    2016-11-15

    In this paper, a Fourier Transform Raman spectroscopy method, to authenticate the provenience of wine, for food traceability applications was developed. In particular, due to the specific chemical fingerprint of the Raman spectrum, it was possible to discriminate different wines produced in the Piedmont area (North West Italy) in accordance with i) grape varieties, ii) production area and iii) ageing time. In order to create a consistent training set, more than 300 samples from tens of different producers were analyzed, and a chemometric treatment of raw spectra was applied. A discriminant analysis method was employed in the classification procedures, providing a classification capability (percentage of correct answers) of 90% for validation of grape analysis and geographical area provenance, and a classification capability of 84% for ageing time classification. The present methodology was applied successfully to raw materials without any preliminary treatment of the sample, providing a response in a very short time. PMID:27283630

  11. Resonant Raman spectroscopy of twisted multilayer graphene.

    PubMed

    Wu, Jiang-Bin; Zhang, Xin; Ijäs, Mari; Han, Wen-Peng; Qiao, Xiao-Fen; Li, Xiao-Li; Jiang, De-Sheng; Ferrari, Andrea C; Tan, Ping-Heng

    2014-01-01

    Graphene and other two-dimensional crystals can be combined to form various hybrids and heterostructures, creating materials on demand with properties determined by the interlayer interaction. This is the case even for a single material, where multilayer stacks with different relative orientation have different optical and electronic properties. Probing and understanding the interface coupling is thus of primary importance for fundamental science and applications. Here we study twisted multilayer graphene flakes with multi-wavelength Raman spectroscopy. We find a significant intensity enhancement of the interlayer coupling modes (C peaks) due to resonance with new optically allowed electronic transitions, determined by the relative orientation of the layers. The interlayer coupling results in a Davydov splitting of the C peak in systems consisting of two equivalent graphene multilayers. This allows us to directly quantify the interlayer interaction, which is much smaller compared with Bernal-stacked interfaces. This paves the way to the use of Raman spectroscopy to uncover the interface coupling of two-dimensional hybrids and heterostructures. PMID:25382099

  12. Characterization and identification of contraband using UV resonant Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lacey, Richard J.; Hayward, Ian P.; Sands, H. S.; Batchelder, David N.

    1997-02-01

    A range of explosives and narcotics have been examined using Raman spectroscopy with 244 nm excitation. This wavelength of excitation eliminates the fluorescence problems associated with excitation at visible wavelengths. Comparison with spectra obtained using visible excitation reveals that resonance Raman scattering is occurring. This results in simplified spectra, and enhanced Raman scattering efficiencies.

  13. Infrared and NIR Raman spectroscopy in medical microbiology

    NASA Astrophysics Data System (ADS)

    Naumann, Dieter

    1998-04-01

    FTIR and FT-NIR Raman spectra of intact microbial cells are highly specific, fingerprint-like signatures which can be used to (i) discriminate between diverse microbial species and strains, (ii) detect in situ intracellular components or structures such as inclusion bodies, storage materials or endospores, (iii) detect and quantify metabolically released CO2 in response to various different substrate, and (iv) characterize growth-dependent phenomena and cell-drug interactions. The characteristic information is extracted from the spectral contours by applying resolution enhancement techniques, difference spectroscopy, and pattern recognition methods such as factor-, cluster-, linear discriminant analysis, and artificial neural networks. Particularly interesting applications arise by means of a light microscope coupled to the spectrometer. FTIR spectra of micro-colonies containing less than 103 cells can be obtained from colony replica by a stamping technique that transfers micro-colonies growing on culture plates to a special IR-sample holder. Using a computer controlled x, y- stage together with mapping and video techniques, the fundamental tasks of microbiological analysis, namely detection, enumeration, and differentiation of micro- organisms can be integrated in one single apparatus. FTIR and NIR-FT-Raman spectroscopy can also be used in tandem to characterize medically important microorganisms. Currently novel methodologies are tested to take advantage of the complementary information of IR and Raman spectra. Representative examples on medically important microorganisms will be given that highlight the new possibilities of vibrational spectroscopies.

  14. Combined fiber probe for fluorescence lifetime and Raman spectroscopy

    PubMed Central

    Dochow, Sebastian; Ma, Dinglong; Latka, Ines; Bocklitz, Thomas; Hartl, Brad; Bec, Julien; Fatakdawala, Hussain; Marple, Eric; Urmey, Kirk; Wachsmann-Hogiu, Sebastian; Schmitt, Michael; Marcu, Laura; Popp, Jürgen

    2016-01-01

    In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. PMID:26093843

  15. Determining the Authenticity of Gemstones Using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Aponick, Aaron; Marchozzi, Emedio; Johnston, Cynthia R.; Wigal, Carl T.

    1998-04-01

    The benefits of laser spectroscopy in the undergraduate curriculum have been the focus of several recent articles in this journal. Raman spectroscopy has been of particular interest since the similarities of Raman to conventional infrared spectroscopy make the interpretation of spectral data well within undergraduate comprehension. In addition, the accessibility to this technology is now within the reach of most undergraduate institutions. This paper reports the development of an experiment using Raman spectroscopy which determines the authenticity of both diamonds and pearls. The resulting spectra provide an introduction to vibrational spectroscopy and can be used in a variety of laboratory courses ranging from introductory chemistry to instrumental analysis.

  16. Evaluation of thyroid tissue by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Teixeira, C. S. B.; Bitar, R. A.; Santos, A. B. O.; Kulcsar, M. A. V.; Friguglietti, C. U. M.; Martinho, H. S.; da Costa, R. B.; Martin, A. A.

    2010-02-01

    Thyroid gland is a small gland in the neck consisting of two lobes connected by an isthmus. Thyroid's main function is to produce the hormones thyroxine (T4), triiodothyronine (T3) and calcitonin. Thyroid disorders can disturb the production of these hormones, which will affect numerous processes within the body such as: regulating metabolism and increasing utilization of cholesterol, fats, proteins, and carbohydrates. The gland itself can also be injured; for example, neoplasias, which have been considered the most important, causing damage of to the gland and are difficult to diagnose. There are several types of thyroid cancer: Papillary, Follicular, Medullary, and Anaplastic. The occurrence rate, in general is between 4 and 7%; which is on the increase (30%), probably due to new technology that is able to find small thyroid cancers that may not have been found previously. The most common method used for thyroid diagnoses are: anamnesis, ultrasonography, and laboratory exams (Fine Needle Aspiration Biopsy- FNAB). However, the sensitivity of those test are rather poor, with a high rate of false-negative results, therefore there is an urgent need to develop new diagnostic techniques. Raman spectroscopy has been presented as a valuable tool for cancer diagnosis in many different tissues. In this work, 27 fragments of the thyroid were collected from 18 patients, comprising the following histologic groups: goitre adjacent tissue, goitre nodular tissue, follicular adenoma, follicular carcinoma, and papillary carcinoma. Spectral collection was done with a commercial FTRaman Spectrometer (Bruker RFS100/S) using a 1064 nm laser excitation and Ge detector. Principal Component Analysis, Cluster Analysis, and Linear Discriminant Analysis with cross-validation were applied as spectral classification algorithm. Comparing the goitre adjacent tissue with the goitre nodular region, an index of 58.3% of correct classification was obtained. Between goitre (nodular region and

  17. Raman spectroscopy: an evolving technique for live cell studies.

    PubMed

    Smith, Rachael; Wright, Karen L; Ashton, Lorna

    2016-06-21

    One of the most exciting developments in Raman spectroscopy in the last decade has been its application to cells and tissues for diagnostic and pharmaceutical applications, and in particular its use in the analysis of cellular dynamics. Raman spectroscopy is rapidly advancing as a cell imaging method that overcomes many of the limitations of current techniques and is earning its place as a routine tool in cell biology. In this review we focus on important developments in Raman spectroscopy that have evolved into the exciting technique of live-cell Raman microscopy and highlight some of the most recent and significant applications to cell biology. PMID:27072718

  18. Molecular imaging with surface-enhanced Raman spectroscopy nanoparticle reporters

    PubMed Central

    Jokerst, Jesse V.; Pohling, Christoph; Gambhir, Sanjiv S.

    2013-01-01

    Molecular imaging scans cellular and molecular targets in living subjects through the introduction of imaging agents that bind to these targets and report their presence through a measurable signal. The picomolar sensitivity, signal stability, and high multiplexing capacity of Raman spectroscopy satisfies important needs within the field of molecular imaging, and several groups now utilize Raman and surface-enhanced Raman spectroscopy to image molecular targets in small animal models of human disease. This article details the role of Raman spectroscopy in molecular imaging, describes some substrates and imaging agents used in animal models, and illustrates some examples. PMID:24293809

  19. Cervical cancer detection based on serum sample Raman spectroscopy.

    PubMed

    González-Solís, José Luis; Martínez-Espinosa, Juan Carlos; Torres-González, Luis Adolfo; Aguilar-Lemarroy, Adriana; Jave-Suárez, Luis Felipe; Palomares-Anda, Pascual

    2014-05-01

    The use of Raman spectroscopy to analyze the biochemical composition of serum samples and hence distinguish between normal and cervical cancer serum samples was investigated. The serum samples were obtained from 19 patients who were clinically diagnosed with cervical cancer, 3 precancer, and 20 healthy volunteer controls. The imprint was put under an Olympus microscope, and around points were chosen for Raman measurement.All spectra were collected at a Horiba Jobin-Yvon LabRAM HR800 Raman Spectrometer with a laser of 830-nm wavelength and 17-mW power irradiation. Raw spectra were processed by carrying out baseline correction, smoothing, and normalization to remove noise, florescence, and shot noise and then analyzed using principal component analysis (PCA). The control serum spectrum showed the presence of higher amounts of carotenoids indicated by peaks at 1,002, 1,160, and 1,523 cm(-1)and intense peaks associated with protein components at 754, 853, 938, 1,002, 1,300-1,345, 1,447, 1,523, 1,550, 1,620, and 1,654 cm(-1). The Raman bands assigned to glutathione (446, 828, and 1,404 cm(-1)) and tryptophan (509, 1,208, 1,556, 1,603, and 1,620 cm(-1)) in cervical cancer were higher than those of control samples, suggesting that their presence may also play a role in cervical cancer. Furthermore, weak bands in the control samples attributed to tryptophan (545, 760, and 1,174 cm(-1)) and amide III (1,234-1,290 cm(-1)) seem to disappear and decrease in the cervical cancer samples, respectively. It is shown that the serum samples from patients with cervical cancer and from the control group can be discriminated with high sensitivity and specificity when the multivariate statistical methods of PCA is applied to Raman spectra. PCA allowed us to define the wavelength differences between the spectral bands of the control and cervical cancer groups by confirming that the main molecular differences among the control and cervical cancer samples were glutathione, tryptophan,

  20. Evaluating internal maturity of tomatoes using spatially offset Raman spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatially offset Raman spectroscopy technique was investigated for evaluating internal maturity of intact tomatoes. A Raman spectroscopy system was assembled to acquire spatially offset spectra in the wavenumber range of 200–2500 cm–1. A 785-nm laser was used as the excitation source and the measure...

  1. Measurement of clathrate hydrates via Raman spectroscopy

    USGS Publications Warehouse

    Sum, A.K.; Burruss, R.C.; Sloan, E.D., Jr.

    1997-01-01

    Raman spectra of clathrate hydrate guest molecules are presented for three known structures (I (sI), II (sII), and H (sH)) in the following systems: CH4 (sI), CO2 (sI), C3H8 (sII), CH4 + CO2 (sI), CD4 + C3H8 (sII), CH4 + N2 (sI), CH4 + THF-d8 (sII), and CH4 + C7D14 (sH). Relative occupancy of CH4 in the large and small cavities of sI were determined by deconvoluting the ??1 symmetric bands, resulting in hydration numbers of 6.04 ?? 0.03. The frequency of the ??1 bands for CH4 in structures I, II, and H differ statistically, so that Raman spectroscopy is a potential tool to identify hydrate crystal structure. Hydrate guest compositions were also measured for two vapor compositions of the CH4 + CO2 system, and they compared favorably with predictions. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities. Hydration numbers from 7.27 to 7.45 were calculated for the mixed hydrate.

  2. Laser Raman Spectroscopy in studies of corrosion and electrocatalysis

    SciTech Connect

    Melendres, C.A.

    1988-01-01

    Laser Raman Spectroscopy (LRS) has become an important tool for the in-situ structural study of electrochemical systems and processes in recent years. Following a brief introduction of the experimental techniques involved in applying LRS to electrochemical systems, we survey the literature for examples of studies in the inhibition of electrode reactions by surface films (e.g., corrosion and passivation phenomena) as well as the acceleration of reactions by electro-sorbates (electrocatalysis). We deal mostly with both normal and resonance Raman effects on fairly thick surface films in contrast to surface-enhanced Raman investigations of monolayer adsorbates, which is covered in another lecture. Laser Raman spectroelectrochemical studies of corrosion and film formation on such metals as Pb, Ag, Fe, Ni, Co, Cr, Au, stainless steel, etc. in various solution conditions are discussed. Further extension of the technique to studies in high-temperature and high-pressure aqueous environments is demonstrated. Results of studies of the structure of corrosion inhibitors are also presented. As applications of the LRS technique in the area of electrocatalysis, we cite studies of the structure of transition metal macrocyclic compounds, i.e., phthalocyanines and porphyrins, used for catalysis of the oxygen reduction reaction. 104 refs., 20 figs.

  3. Molecular velocimetry using stimulated Raman spectroscopy

    NASA Technical Reports Server (NTRS)

    Exton, R. J.; Hillard, M. E.

    1984-01-01

    Molecular flow velocity of N2 was measured in a supersonic wind tunnel using inverse Raman spectroscopy. This technique employs the large Doppler shift exhibited by the molecules when the pump and probe laser beams are counter-propagating (backward scattering). A retrometer system is employed to yield a vibration-free optical configuration which has the additional advantage of obtaining both the forward and backward scattered spectra simultaneously. The linebreadths and their relative Doppler shift can be used to determine the static pressure, translational temperature, and molecular flow velocity. A demonstration of the concept was performed in a supersonic wind tunnel and included: (1) measurements over the Mach number range 2.50 to 4.63; (2) static pressure measurements (at Mach 2.50) corresponding to a Reynolds number per foot range of 1 to 5 x 10 to the 6th power; and (3) measurements behind the shock wave of a flat plate model.

  4. FT Raman spectroscopy of Norway spruce needles

    NASA Astrophysics Data System (ADS)

    Matejka, P.; Pleserova, L.; Budinova, G.; Havirova, K.; Nahlik, J.; Skacel, F.; Volka, Karel

    2001-02-01

    12 Norway spruce [Picea abies (L.) Karst.] needles represent a very useful bioindicator of the air pollution. They serve not only as natural samplers of the pollutants but micromorphology of the epistomatal area can be directly correlated with an environmental stress. The needles of trees growing in polluted areas exhibit different types of injury to the epicuticular wax layer. It is evident that these changes of the morphology of the wax layers are connected also with the changes of their chemical composition and so a potential of the FT Raman spectroscopy was tested to serve as a screening method of these changes. In this work variability of the spectra with the age and with the position in the tree, in the locality, and also in the different localities of the Czech Republic was studied and evaluated in comparison with results of electron scanning microscopy.

  5. Surface-enhanced Raman spectroscopy of peptides

    NASA Astrophysics Data System (ADS)

    Garrell, Robin L.; Herne, Tonya M.; Ahern, Angela M.; Sullenberger, Eve L.

    1990-07-01

    Surface-enhanced Raman (SER) spectroscopy has been used to probe the adsorption, surface interactions, and orientations of peptides on metal surfaces. Amino acids in homodipeptides give SER spectra with unique features that can be used to characterize the surface interactions of specific functional groups in more complicated peptides. In heterodipeptides, there is a hierarchy of functional group-surface interactions that prescribe their orientation and conformation on metal surfaces. By establishing this hierarchy, it is now possible to predict the interactions that occur between larger peptides and surfaces. Furthermore, the observed trends suggest that it should be possible to control these interactions by varying the solution pH, the charge on the surface, and other parameters of the measurement in order to adsorb species selectively from mixtures of peptides in solution. Potential biomedical applications of this technique will be described.

  6. Detection of hazardous chemicals using field-portable Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wright, Cherylyn W.; Harvey, Scott D.; Wright, Bob W.

    2003-07-01

    A major challenge confronting emergency response, border control, and other security-related functions is the accurate, rapid, and safe identification of potentially hazardous chemicals outside a laboratory environment. Raman spectroscopy is a rapid, non-intrusive technique that can be used to confidently identify many classes of hazardous and potentially explosive compounds based on molecular vibration information. Advances in instrumentation now allow reliable field - portable measurements to be made. Before the Raman technique can be effectively applied and be accepted within the scientific community, realistic studies must be performed to develop methods, define limitations, and rigorously evaluate its effectiveness. Examples of a variety of chemicals (including neat and diluted chemical warfare [CW] agents, a CW agent precursor, a biological warfare (BW)-related compound, an illicit drug, and explosives) identified using Raman spectroscopy in various types of containers and on surfaces are given, as well as results from a blind field test of 29 unknown samples which included CW agent precursors and/or degradation products, solvents associated with CW agent production, pesticides, explosives, and BW toxins (mostly mycotoxins). Additionally, results of experimental studies to evaluate the analysis of flammable organic solvents, propellants, military explosives, mixtures containing military explosives, shock-sensitive explosives, and gun powders are described with safety guidelines. Spectral masks for screening unknown samples for explosives and nerve agents are given.

  7. [The Quantitative Analysis of Raman Spectroscopy to Sulfate Ion in Aqueous Solution].

    PubMed

    Wang, Qian-qian; Sun, Qiang

    2016-02-01

    As a non-destructive and non-contact method, Raman spectroscopy has been widely applied in many research fields. Based on vibrational wavenumber, Raman spectroscopy is usually applied to determine the molecular species. Therefore, Raman quantitative analysis is necessary. In this study, according to the theoretical analysis of Raman intensity, Raman quantitative measurement should be fulfilled by relative intensity ratio, which can be divided into internal and external standards. This eliminates the influence of the measurement conditions. For aqueous solution, it is reasonable to treat the OH stretching band of water as an internal standard to determine the solute concentrations in aqueous solution. The Raman spectra of Na₂SO₄-H₂O, K₂SO₄-H₂O and NaCl-Na₂SO₄-H₂O are recorded in the paper. In addition, the Raman OH stretching band of water can be fitted into two Gaussian sub-bands. The intensity proportion I(SO₄²⁻)/I(W) is used to determine the molarity of sulfate in aqueous solution, where I(SO₄²⁻) represents the intensity of sulfate band and I(W) represents the sum of the two sub-bands of Raman OH stretching bands of water. Therefore, Raman spectroscopy can be utilized to measure the SO₄²⁻concentrations in aqueous solutions. PMID:27209744

  8. FT-Raman, surface-enhanced Raman spectroscopy and theoretical investigations of diclofenac sodium

    NASA Astrophysics Data System (ADS)

    Iliescu, T.; Baia, M.; Kiefer, W.

    2004-03-01

    Raman and surface-enhanced Raman (SER) spectroscopies have been applied to the vibrational characterization of diclofenac sodium (DCF-Na). Theoretical calculations (DFT and ab initio) of two DCF-Na conformers have been performed to find the optimized structure and computed vibrational wavenumbers of the most stable one. SER spectra in silver colloid at different pH values have been also recorded and analyzed. Good SER spectra have been obtained in acidic and neutral environments, proving the chemisorption of the DCF-Na molecule on the silver surface. In the investigated pH range the carboxylate anion has been bonded to the silver surface through the lone pair oxygen electrons. The phenyl rings' orientation with respect to the silver surface changed on passing from acidic to neutral pH from a tilted close to flat to a more perpendicular one.

  9. Raman spectroscopy of human saliva for acute myocardial infarction detection

    NASA Astrophysics Data System (ADS)

    Chen, Maowen; Chen, Yuanxiang; Wu, Shanshan; Huang, Wei; Lin, Jinyong; Weng, Guo-Xing; Chen, Rong

    2014-09-01

    Raman spectroscopy is a rapidly non-invasive technique with great potential for biomedical research. The aim of this study was to evaluate the feasibility of using Raman spectroscopy of human saliva for acute myocardial infarction (AMI) detection. Raman spectroscopy measurements were performed on two groups of saliva samples: one group from patients (n=30) with confirmed AMI and the other group from healthy controls (n=31). The diagnostic performance for differentiating AMI saliva from normal saliva was evaluated by multivariate statistical analysis. The combination of principal component analysis (PCA) and linear discriminate analysis (LDA) of the measured Raman spectra separated the spectral features of the two groups into two distinct clusters with little overlaps, rendering the sensitivity of 80.0% and specificity of 80.6%. The results from this exploratory study demonstrated that Raman spectroscopy of human saliva can serve as a potentially clinical tool for rapid AMI detection and screening.

  10. Raman spectroscopy for optical diagnosis of laryngeal cancer

    NASA Astrophysics Data System (ADS)

    Teh, Seng Khoon; Zheng, Wei; Lau, David P.; Huang, Zhiwei

    2008-02-01

    In this report, the diagnostic ability of near-infrared (NIR) Raman spectroscopy for identifying the malignant tumors from normal tissues in the larynx was studied. A rapid NIR Raman system was utilized. Multivariate statistical techniques were employed to develop effective diagnostic algorithms. Raman spectra in the range of 800-1,800 cm-1 differed significantly between normal and malignant tumor tissues. The diagnostic algorithms can yielded a diagnostic sensitivity of 92.9% and specificity 83.3% for separating malignant tumors from normal laryngeal tissues. NIR Raman spectroscopy with multivariate statistical techniques has a potential for the non-invasive detection of malignant tumors in the larynx.

  11. From Femtosecond Dynamics to Breast Cancer Diagnosis by Raman Spectroscopy

    SciTech Connect

    Abramczyk, H.; Placek, I.; Brozek-Pluska, B.; Kurczewski, K.; Morawiec, Z.; Tazbir, M.

    2007-12-26

    This paper presents new results based on Raman spectroscopy and demonstrates its utilisation as a diagnostic and development tool with the key advantage in breast cancer research. Applications of Raman spectroscopy in cancer research are in the early stages of development. However, research presented here as well as performed in a few other laboratories demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The main goals of bio-Raman spectroscopy at this stage are threefold. Firstly, the aim is to develop the diagnostic ability of Raman spectroscopy so it can be implemented in a clinical environment, producing accurate and rapid diagnoses. Secondly, the aim is to optimize the technique as a diagnostic tool for the non-invasive real time medical applications. Thirdly, the aim is to formulate some hypothesis based on Raman spectroscopy on the molecular mechanism which drives the transformation of normal human cells into highly malignant derivatives. To the best of our knowledge, this is the most statistically reliable report on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

  12. From Femtosecond Dynamics to Breast Cancer Diagnosis by Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Abramczyk, H.; Placek, I.; BroŻek-Płuska, B.; Kurczewski, K.; Morawiec, Z.; Tazbir, M.

    2007-12-01

    This paper presents new results based on Raman spectroscopy and demonstrates its utilisation as a diagnostic and development tool with the key advantage in breast cancer research. Applications of Raman spectroscopy in cancer research are in the early stages of development. However, research presented here as well as performed in a few other laboratories demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The main goals of bio-Raman spectroscopy at this stage are threefold. Firstly, the aim is to develop the diagnostic ability of Raman spectroscopy so it can be implemented in a clinical environment, producing accurate and rapid diagnoses. Secondly, the aim is to optimize the technique as a diagnostic tool for the non-invasive real time medical applications. Thirdly, the aim is to formulate some hypothesis based on Raman spectroscopy on the molecular mechanism which drives the transformation of normal human cells into highly malignant derivatives. To the best of our knowledge, this is the most statistically reliable report on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

  13. The many facets of Raman spectroscopy for biomedical analysis.

    PubMed

    Krafft, Christoph; Popp, Jürgen

    2015-01-01

    A critical review is presented on the use of linear and nonlinear Raman microspectroscopy in biomedical diagnostics of bacteria, cells, and tissues. This contribution is combined with an overview of the achievements of our research group. Linear Raman spectroscopy offers a wealth of chemical and molecular information. Its routine clinical application poses a challenge due to relatively weak signal intensities and confounding overlapping effects. Nonlinear variants of Raman spectroscopy such as coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) have been recognized as tools for rapid image acquisition. Imaging applications benefit from the fact that contrast is based on the chemical composition and molecular structures in a label-free and nondestructive manner. Although not label-free, surface enhanced Raman scattering (SERS) has also been recognized as a complementary biomedical tool to increase sensitivity. The current state of the art is evaluated, illustrative examples are given, future developments are pointed out, and important reviews and references from the current literature are selected. The topics are identification of bacteria and single cells, imaging of single cells, Raman activated cell sorting, diagnosis of tissue sections, fiber optic Raman spectroscopy, and progress in coherent Raman scattering in tissue diagnosis. The roles of networks-such as Raman4clinics and CLIRSPEC on a European level-and early adopters in the translation, dissemination, and validation of new methods are discussed. PMID:25428454

  14. Raman spectroscopy of gliomas: an exploratory study

    NASA Astrophysics Data System (ADS)

    Shenoy, Mahesh; Hole, Arti R.; Shridhar, E.; Moiyadi, Aliasgar V.; Krishna, C. Murali

    2014-03-01

    Gliomas are extremely infiltrative type of brain cancers, the borders of which are difficult to locate. Gliomas largely consist of tumors of astrocytic or oligodendroglial lineage. Usually stereotactic surgery is performed to obtain tumor tissue sample. Complete excision of these tumors with preservation of uninvolved normal areas is important during brain tumor surgeries. The present study was undertaken to explore feasibility of classifying abnormal and normal glioma tissues with Raman spectroscopy (RS). RS is a nondestructive vibrational spectroscopic technique, which provides information about molecular composition, molecular structures and molecular interactions in tissue. Postoperated 33 (20-abnormal and 13-normal) gliomas tissue samples of different grades were collected under clinical supervision. Five micron section from tissue sample was used for confirmatory histopathological diagnosis while the remaining tissue was placed on CaF2 window and spectra were acquired using a fiberoptic-probe-coupled HE-785 Raman-spectrometer. Spectral acquisition parameters were laser power-80mW, integration-20s and averaged over 3 accumulations. Spectra were pre-processed and subjected to unsupervised Principal-Component Analysis (PCA) to identify trends of classification. Supervised PC-LDA (Principal-Component-Linear-Discriminant Analysis) was used to develop standard-models using spectra of 12 normal and abnormal specimens each. Leave-one-out crossvalidation yielded classification-efficiency of 90% and 80% for normal and abnormal conditions, respectively. Evaluation with an independent-test data-set comprising of 135 spectra of 9 samples provided sensitivity of 100% and specificity of 70%. Findings of this preliminary study may pave way for objective tumor margin assessment during brain surgery.

  15. New Applications of Portable Raman Spectroscopy in Agri-Bio-Photonics

    NASA Astrophysics Data System (ADS)

    Voronine, Dmitri; Scully, Rob; Sanders, Virgil

    2014-03-01

    Modern optical techniques based on Raman spectroscopy are being used to monitor and analyze the health of cattle, crops and their natural environment. These optical tools are now available to perform fast, noninvasive analysis of live animals and plants in situ. We will report new applications of a portable handheld Raman spectroscopy to identification and taxonomy of plants. In addition, detection of organic food residues will be demonstrated. Advantages and limitations of current portable instruments will be discussed with suggestions for improved performance by applying enhanced Raman spectroscopic schemes.

  16. Nanoparticle Based Surface-Enhanced Raman Spectroscopy

    SciTech Connect

    Talley, C E; Huser, T R; Hollars, C W; Jusinski, L; Laurence, T; Lane, S M

    2005-01-03

    Surface-enhanced Raman scattering is a powerful tool for the investigation of biological samples. Following a brief introduction to Raman and surface-enhanced Raman scattering, several examples of biophotonic applications of SERS are discussed. The concept of nanoparticle based sensors using SERS is introduced and the development of these sensors is discussed.

  17. Periodontitis diagnostics using resonance Raman spectroscopy on saliva

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Biryukova, T.; Tsvetkov, M.; Bagratashvily, V.

    2013-07-01

    In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm-1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva.

  18. Investigation of biomineralization by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Fatscher, Robert William

    Biomineralization is a process in which living organism grow composite materials consisting of inorganic and organic materials. This produces a composite material consisting of both inorganic and organic components, with superior mechanical properties. In the human body bone and dentin are both examples of biominerals. In this research Raman spectroscopy was used to characterize dentin from mice and human teeth, to determine composition. In the mouse tooth samples areas of irregular dentin were found, along the inside of the tooth, to be in the process of mineralization. By analyzing the samples along these areas we were able to determine the composition of dentin and track how it changed in these area. By analysis of the mineral to matrix ratio the areas of irregular dentin were determined to have less mineral present. Observations of other organic components and collagen in increased concentrations in this area suggested these area were in the process of biomineralization. The understanding of the structure of dentin and its biomineralization process is of crucial importance when trying reproduce dentin. Scientists and engineers are able to produce dentin minerals in vitro by culturing various dental stem cells. The ability to create dentin mineral from cells could lead to methods of repairing dentin in patients, or even lead to the creation of a completely engineered tooth. While dentin-like materials can be produced in a laboratory environment, analysis and comparison of the composition of these materials must be performed to ensure the mineral produced is consistent with dentin. Mineralized nodules from six different dental stem cell lines were cultured to produce a mineralized deposit. Utilizing Raman spectroscopy, we were able to determine cell source dependent differences in a variety of dental stem cells, and compare the mineral produced to native dentin. Orthopedic implants are implants used to replace damaged bone, examples include knee, hip and dental

  19. Sensitivity of Raman spectroscopy to normal patient variability

    NASA Astrophysics Data System (ADS)

    Vargis, Elizabeth; Byrd, Teresa; Logan, Quinisha; Khabele, Dineo; Mahadevan-Jansen, Anita

    2011-11-01

    Many groups have used Raman spectroscopy for diagnosing cervical dysplasia; however, there have been few studies looking at the effect of normal physiological variations on Raman spectra. We assess four patient variables that may affect normal Raman spectra: Race/ethnicity, body mass index (BMI), parity, and socioeconomic status. Raman spectra were acquired from a diverse population of 75 patients undergoing routine screening for cervical dysplasia. Classification of Raman spectra from patients with a normal cervix is performed using sparse multinomial logistic regression (SMLR) to determine if any of these variables has a significant effect. Results suggest that BMI and parity have the greatest impact, whereas race/ethnicity and socioeconomic status have a limited effect. Incorporating BMI and obstetric history into classification algorithms may increase sensitivity and specificity rates of disease classification using Raman spectroscopy. Studies are underway to assess the effect of these variables on disease.

  20. Clinical instrumentation and applications of Raman spectroscopy.

    PubMed

    Pence, Isaac; Mahadevan-Jansen, Anita

    2016-04-01

    Clinical diagnostic devices provide new sources of information that give insight about the state of health which can then be used to manage patient care. These tools can be as simple as an otoscope to better visualize the ear canal or as complex as a wireless capsule endoscope to monitor the gastrointestinal tract. It is with tools such as these that medical practitioners can determine when a patient is healthy and to make an appropriate diagnosis when he/she is not. The goal of diagnostic medicine then is to efficiently determine the presence and cause of disease in order to provide the most appropriate intervention. The earliest form of medical diagnostics relied on the eye - direct visual observation of the interaction of light with the sample. This technique was espoused by Hippocrates in his 5th century BCE work Epidemics, in which the pallor of a patient's skin and the coloring of the bodily fluids could be indicative of health. In the last hundred years, medical diagnosis has moved from relying on visual inspection to relying on numerous technological tools that are based on various types of interaction of the sample with different types of energy - light, ultrasound, radio waves, X-rays etc. Modern advances in science and technology have depended on enhancing technologies for the detection of these interactions for improved visualization of human health. Optical methods have been focused on providing this information in the micron to millimeter scale while ultrasound, X-ray, and radio waves have been key in aiding in the millimeter to centimeter scale. While a few optical technologies have achieved the status of medical instruments, many remain in the research and development phase despite persistent efforts by many researchers in the translation of these methods for clinical care. Of these, Raman spectroscopy has been described as a sensitive method that can provide biochemical information about tissue state while maintaining the capability of delivering

  1. Clinical instrumentation and applications of Raman spectroscopy

    PubMed Central

    Pence, Isaac

    2016-01-01

    Clinical diagnostic devices provide new sources of information that give insight about the state of health which can then be used to manage patient care. These tools can be as simple as an otoscope to better visualize the ear canal or as complex as a wireless capsule endoscope to monitor the gastrointestinal tract. It is with tools such as these that medical practitioners can determine when a patient is healthy and to make an appropriate diagnosis when he/she is not. The goal of diagnostic medicine then is to efficiently determine the presence and cause of disease in order to provide the most appropriate intervention. The earliest form of medical diagnostics relied on the eye – direct visual observation of the interaction of light with the sample. This technique was espoused by Hippocrates in his 5th century BCE work Epidemics, in which the pallor of a patient’s skin and the coloring of the bodily fluids could be indicative of health. In the last hundred years, medical diagnosis has moved from relying on visual inspection to relying on numerous technological tools that are based on various types of interaction of the sample with different types of energy – light, ultrasound, radio waves, X-rays etc. Modern advances in science and technology have depended on enhancing technologies for the detection of these interactions for improved visualization of human health. Optical methods have been focused on providing this information in the micron to millimeter scale while ultrasound, X-ray, and radio waves have been key in aiding in the millimeter to centimeter scale. While a few optical technologies have achieved the status of medical instruments, many remain in the research and development phase despite persistent efforts by many researchers in the translation of these methods for clinical care. Of these, Raman spectroscopy has been described as a sensitive method that can provide biochemical information about tissue state while maintaining the capability of

  2. [Water Raman spectrum suppression with low-pass filter in underwater in-situ Raman spectroscopy].

    PubMed

    Guo, Jin-Jia; Liu, Zhi-Shen

    2011-09-01

    As a powerful tool for studying chemical structures, Raman spectroscopy has been used in aquatic environments in-situ measurement widely, and has been used in deep sea research recently. For underwater in-situ detection, O-H vibration Raman peak of water is inherent and strong compared with other dissolved matter's Raman signals. When the authors want to get a good SNR Raman signal of dissolved matter by increasing detection time, O-H vibration Raman peak of water will get to saturation easily, which influences other Raman signal's detection. In the present paper, a specially designed short-pass optical filter was used for suppression of water's O-H vibration Raman peak. The authors calculated the suppression effect of short-pass optical filter with linear and exponential edges. The simulation shows that exponential edge filter has better performance and can suppress water's O-H vibration Raman peak effectively. The experiment also proves the calculation results. With the suppression optical filter, the intensity of water's O-H vibration Raman signal and other dissolved matters' become similar. And the influence of suppression optical filter on other dissolved matters' Raman signal is little. So the suppression optical filter is feasible for in-situ underwater Raman spectroscopy. PMID:22097842

  3. Application of Raman Spectroscopy for Nondestructive Evaluation of Composite Materials

    NASA Technical Reports Server (NTRS)

    Washer, Glenn A.; Brooks, Thomas M. B.; Saulsberry, Regor

    2007-01-01

    This paper will present an overview of efforts to investigate the application of Raman spectroscopy for the characterization of Kevlar materials. Raman spectroscopy is a laser technique that is sensitive to molecular interactions in materials such as Kevlar, graphite and carbon used in composite materials. The overall goal of this research reported here is to evaluate Raman spectroscopy as a potential nondestructive evaluation (NDE) tool for the detection of stress rupture in Kevlar composite over-wrapped pressure vessels (COPVs). Characterization of the Raman spectra of Kevlar yarn and strands will be presented and compared with analytical models provided in the literature. Results of testing to investigate the effects of creep and high-temperature aging on the Raman spectra will be presented.

  4. Applications of spatially offset Raman spectroscopy to defense and security

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason; Hopkins, Rebecca

    2016-05-01

    Spatially offset Raman spectroscopy (SORS) allows for sub-surface and through barrier detection and has applications in drug analysis, cancer detection, forensic science, as well as defense and security. This paper reviews previous efforts in SORS and other through barrier Raman techniques and presents a discussion on current research in defense and security applications.

  5. Cryoprotectant redistribution along the frozen straw probed by Raman spectroscopy.

    PubMed

    Karpegina, Yu A; Okotrub, K A; Brusentsev, E Yu; Amstislavsky, S Ya; Surovtsev, N V

    2016-04-01

    The distribution of cryoprotectant (10% glycerol) and ice along the frozen plastic straw (the most useful container for freezing mammalian semen, oocytes and embryos) was studied by Raman scattering technique. Raman spectroscopy being a contactless, non-invasive tool was applied for the straws filled with the cryoprotectant solution and frozen by controlled rate programs commonly used for mammalian embryos freezing. Analysis of Raman spectra measured at different points along the straw reveals a non-uniform distribution of the cryoprotectant. The ratio between non-crystalline solution and ice was found to be increased by several times at the bottom side of the solution column frozen by the standard freezing program. The increase of the cryoprotectant fraction occurs in the area where embryos or oocytes are normally placed during their freezing. Possible effects of the cooling rate and the ice nucleation temperature on the cryoprotectant fraction at the bottom side of the solution column were considered. Our findings highlight that the ice fraction around cryopreserved embryos or oocytes can differ significantly from the averaged one in the frozen plastic straws. PMID:26794460

  6. [Identification of B jade by Raman spectroscopy].

    PubMed

    Zu, En-dong; Chen, Da-peng; Zhang, Peng-xiang

    2003-02-01

    Raman spectroscopy has been found to be a useful tool for identification of bleached and polymer-impregnated jadeites (so-called B jade). The major advantage of this system over classical methods of gem testing is the non-destructive identification of inclusions in gemstones and the determination of organic fracture filling in jade. Fissures in jadeites have been filled with oils and various resins to enhance their clarity, such as paraffin wax, paraffin oil, AB glue and epoxy resins. They show different peaks depending on their chemical composition. The characteristic spectrum ranges from 1,200-1,700 cm-1 to 2,800-3,100 cm-1. The spectra of resins show that they all have four strongest peaks related with phenyl: two C-C stretching modes at 1,116 and 1,609 cm-1, respectively, one C-H stretching mode at 3,069 cm-1, and a in-plane C-H bending mode at 1,189 cm-1. In addition, other two -CH2, -CH3 stretching modes at 2,906 and 2,869 cm-1, respectively, are very similar to paraffin. Therefore, the peaks at 1,116, 1,609, 1,189 and 3,069 cm-1 are important in distinguishing resin from paraffin, and we can identify B jade depending on them. PMID:12939970

  7. Electrochemical Tip-Enhanced Raman Spectroscopy.

    PubMed

    Zeng, Zhi-Cong; Huang, Sheng-Chao; Wu, De-Yin; Meng, Ling-Yan; Li, Mao-Hua; Huang, Teng-Xiang; Zhong, Jin-Hui; Wang, Xiang; Yang, Zhi-Lin; Ren, Bin

    2015-09-23

    Interfacial properties are highly important to the performance of some energy-related systems. The in-depth understanding of the interface requires highly sensitive in situ techniques that can provide fingerprint molecular information at nanometer resolution. We developed an electrochemical tip-enhanced Raman spectroscopy (EC-TERS) by introduction of the light horizontally to the EC-STM cell to minimize the optical distortion and to keep the TERS measurement under a well-controlled condition. We obtained potential-dependent EC-TERS from the adsorbed aromatic molecule on a Au(111) surface and observed a substantial change in the molecule configuration with potential as a result of the protonation and deprotonation of the molecule. Such a change was not observable in EC-SERS (surface-enhanced), indicating EC-TERS can more faithfully reflect the fine interfacial structure than EC-SERS. This work will open a new era for using EC-TERS as an important nanospectroscopy tool for the molecular level and nanoscale analysis of some important electrochemical systems including solar cells, lithium ion batteries, fuel cells, and corrosion. PMID:26351986

  8. Wavelength dependent resonance Raman band intensity of broadband stimulated Raman spectroscopy of malachite green in ethanol

    NASA Astrophysics Data System (ADS)

    Cen, Qiongyan; He, Yuhan; Xu, Mei; Wang, Jingjing; Wang, Zhaohui

    2015-03-01

    Resonance broadband stimulated Raman spectroscopy of malachite green in ethanol has been performed. With a tuning picosecond visible laser source and a broadband Raman probe, the Raman gain and loss spectra have been measured simultaneously. By scanning the Raman pump across the first absorption band of the molecule, we found that the resonant Raman bands could be only seen when the pump laser tuned in the range of the red edge of the S1←S0 transition. Dispersive lineshapes of resonant Raman bands have been observed in the Raman loss spectra, while the line shape is normal (same as spontaneous Raman) in the Raman gain spectra. Although, the resonant bands in the loss spectrum are usually stronger than that in the gain spectrum, the band intensities of both loss and gain linearly increase with the pump energy. The relative magnitude of each corresponding resonant band in the Raman loss and gain varies with the pump wavelength. Mode specified Raman excitation profiles have been obtained through broadband stimulated Raman measurement.

  9. Raman Spectroscopy for the Investigation of Carbon Based Black Pigments

    NASA Astrophysics Data System (ADS)

    Coccato, A.; Jehlicka, J.; Moens, L.; Vandenabeele, P.

    2014-06-01

    Carbon based black pigments play an important role among artists' materials. The disordered structure of these materials is investigated by means of Raman spectroscopy, which helps in the comprehension of their production processes.

  10. Analysis of Arctic Carbonates Profiles by Raman Spectroscopy using Exomars Raman Laser Spectrometer

    NASA Astrophysics Data System (ADS)

    Sansano, A.; López, G.; Medina, J.; Rull, F.

    2011-10-01

    This work details the analysis performed by Raman spectroscopy on carbonate samples from the Svalbard Islands (Norway) in the Arctic. This place is considered a potential Martian analog because the carbonate formation show close similarities with the formation in ALH84001 meteorite. The results obtained illustrate the performances of the Raman instrument included in the Exomars (ESA) mission.

  11. Spatially offset Raman spectroscopy based on a line-scan hyperspectral Raman system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatially offset Raman spectroscopy (SORS) is a technique that can obtain subsurface layered information by collecting Raman spectra from a series of surface positions laterally offset from the excitation laser. The current methods of SORS measurement are typically either slow due to mechanical move...

  12. Quantitative Raman spectroscopy in turbid media

    NASA Astrophysics Data System (ADS)

    Reble, Carina; Gersonde, Ingo; Andree, Stefan; Eichler, Hans Joachim; Helfmann, Jürgen

    2010-05-01

    Intrinsic Raman spectra of biological tissue are distorted by the influences of tissue absorption and scattering, which significantly challenge signal quantification. A combined Raman and spatially resolved reflectance setup is introduced to measure the absorption coefficient μa and the reduced scattering coefficient μs' of the tissue, together with the Raman signals. The influence of μa and μs' on the resonance Raman signal of β-carotene is measured at 1524 cm-1 by tissue phantom measurements and Monte Carlo simulations for μa=0.01 to 10 mm-1 and μs'=0.1 to 10 mm-1. Both methods show that the Raman signal drops roughly proportional to 1/μa for μa>0.2 mm-1 in the measurement geometry and that the influence of μs' is weaker, but not negligible. Possible correction functions dependent on the elastic diffuse reflectance are investigated to correct the Raman signal for the influence of μa and μs', provided that μa and μs' are measured as well. A correction function based on the Monte Carlo simulation of Raman signals is suggested as an alternative. Both approaches strongly reduce the turbidity-induced variation of the Raman signals and allow absolute Raman scattering coefficients to be determined.

  13. Micro-Raman spectroscopy for meat type detection

    NASA Astrophysics Data System (ADS)

    De Biasio, M.; Stampfer, P.; Leitner, R.; Huck, C. W.; Wiedemair, V.; Balthasar, D.

    2015-06-01

    The recent horse meat scandal in Europe increased the demand for optical sensors that can identify meat type. Micro-Raman spectroscopy is a promising technique for the discrimination of meat types. Here, we present micro-Raman measurements of chicken, pork, turkey, mutton, beef and horse meat test samples. The data was analyzed with different combinations of data normalization and classification approaches. Our results show that Raman spectroscopy can discriminate between different meat types. Red and white meat are easily discriminated, however a sophisticated chemometric model is required to discriminate species within these groups.

  14. Dispersive Raman spectroscopy allows the identification and quantification of melanin types.

    PubMed

    Galván, Ismael; Jorge, Alberto

    2015-04-01

    Melanins are the most prevalent pigments in animals and are involved in visual communication by producing colored traits that often evolve as intraspecific signals of quality. Identifying and quantifying melanins are therefore essential to understand the function and evolution of melanin-based signals. However, the analysis of melanins is difficult due to their insolubility and the lack of simple methods that allow the identification of their chemical forms. We recently proposed the use of Raman spectroscopy as a simple, noninvasive technique that can be used to identify and quantify melanins in feathers and hairs. Contrarily, other authors later stated that melanins are characterized by a lack of defined Raman signals. Here, we use confocal Raman microscopy to confirm previous analyses showing that the two main chemical forms of melanins (eumelanin and pheomelanin) exhibit distinct Raman signal and compare different excitation wavelengths to analyze synthetic pheomelanin and natural melanins in feathers of different species of birds. Our analyses indicate that only laser excitation wavelengths below 1064 nm are useful for the analysis of melanins by Raman spectroscopy, and only 780-nm laser in the case of melanins in feathers. These findings show that the capacity of Raman spectroscopy to distinguish different chemical forms of melanins depends on laser power and integration time. As a consequence, Raman spectroscopy should be applied after preliminar analyses using a range of these parameters, especially in fragile biological tissues such as feathers. PMID:25897382

  15. Dispersive Raman spectroscopy allows the identification and quantification of melanin types

    PubMed Central

    Galván, Ismael; Jorge, Alberto

    2015-01-01

    Melanins are the most prevalent pigments in animals and are involved in visual communication by producing colored traits that often evolve as intraspecific signals of quality. Identifying and quantifying melanins are therefore essential to understand the function and evolution of melanin-based signals. However, the analysis of melanins is difficult due to their insolubility and the lack of simple methods that allow the identification of their chemical forms. We recently proposed the use of Raman spectroscopy as a simple, noninvasive technique that can be used to identify and quantify melanins in feathers and hairs. Contrarily, other authors later stated that melanins are characterized by a lack of defined Raman signals. Here, we use confocal Raman microscopy to confirm previous analyses showing that the two main chemical forms of melanins (eumelanin and pheomelanin) exhibit distinct Raman signal and compare different excitation wavelengths to analyze synthetic pheomelanin and natural melanins in feathers of different species of birds. Our analyses indicate that only laser excitation wavelengths below 1064 nm are useful for the analysis of melanins by Raman spectroscopy, and only 780-nm laser in the case of melanins in feathers. These findings show that the capacity of Raman spectroscopy to distinguish different chemical forms of melanins depends on laser power and integration time. As a consequence, Raman spectroscopy should be applied after preliminar analyses using a range of these parameters, especially in fragile biological tissues such as feathers. PMID:25897382

  16. Nanogap structures: combining enhanced Raman spectroscopy and electronic transport.

    PubMed

    Natelson, Douglas; Li, Yajing; Herzog, Joseph B

    2013-04-21

    Surface-enhanced Raman spectroscopy (SERS) is an experimental tool for accessing vibrational and chemical information, down to the single molecule level. SERS typically relies on plasmon excitations in metal nanostructures to concentrate the incident radiation and to provide an enhanced photon density of states to couple emitted radiation to the far field. Many common SERS platforms involve metal nanoparticles to generate the required electromagnetic enhancements. Here we concentrate on an alternative approach, in which the relevant plasmon excitations are supported at a truly nanoscale gap between extended electrodes, rather than discrete subwavelength nanoparticles. The ability to fabricate precise gaps on demand, and in some cases to tune the gap size in situ, combined with the additional capability of simultaneous electronic transport measurements of the nanogap, provides access to information not previously available in standard SERS. We summarize the rich plasmonic physics at work in these extended systems and highlight the recent state of the art including tip-enhanced Raman spectroscopy (TERS) and the application of mechanical break junctions and electromigrated junctions. We describe in detail how we have performed in situ gap-enhanced Raman measurements of molecular-scale junctions while simultaneously subjecting these structures to electronic transport. These extended electrode structures allow us to study the pumping of vibrational modes by the flow of tunneling electrons, as well as the shifting of vibrational energies due to the applied bias. These experiments extend SERS into a tool for examining fundamental processes of dissipation, and provide insight into the mechanisms behind SERS spectral diffusion. We conclude with a brief discussion of future directions. PMID:23385304

  17. Coherent and spontaneous Raman spectroscopy in shocked and unshocked liquids

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.; Schiferl, D.; Chatelet, M.; Turner, T.P.; Shaner, J.W.; Shampine, D.L.; Holt, W.T.

    1985-01-01

    Coherent and non-coherent Raman spectroscopy is being used to study the structure and energy transfer in molecular liquids at high pressures. Stimulated Raman scattering, coherent anti-Stokes Raman scattering, and Raman induced Kerr effect scattering measurements have been performed in liquid benzene and liquid nitromethane shocked to pressures up to 11 GPa. Frequency shifts were observed for the 992 cm/sup -1/ ring stretching mode of benzene and the 920 cm/sup -1/ CN stretching mode of nitromethane. Results of these dynamic experiments are compared to spontaneous Raman scattering measurements made in a high temperature diamond anvil cell. Also, a picosecond infrared pump/spontaneous anti-Strokes Raman probe experiment is being used to measure CH stretch vibrational relaxation times in liquid halogenated methanes statically compressed to a few tenths GPa. 87 refs., 17 figs.

  18. Micro-Raman spectroscopy on oral tissues

    NASA Astrophysics Data System (ADS)

    Zenone, F.; Lepore, M.; Perna, G.; Carmone, P.; Riccio, R.; Gaeta, G. M.; Capozzi, V.

    2006-02-01

    Micro-Raman Spectroscopy (μ-RS) provides a unique tool in medicine for a not invasive and real time analysis of biological tissue for biopsy and "in vivo" investigation. Based on the evaluation of molecular vibration frequencies, the μ-RS is able to detect the main molecular bonds of protein constituents, as the C-H and C-C ones. Changes in frequency or in the relative intensity of the vibration modes revealed by μ-RS can be related to changes of chemical bond and of protein structure induced by pathology. The μ-RS has been performed on samples of oral tissue from informed patients, affected by pemphigus vulgaris (an oral pathology) in an advanced regression state. The biopsies were thin slices (about 1mm thick) with 6mm diameter. The sample was measured through a 170 μm thick cover-glass. The experimental set-up was mainly composed by a He-Ne laser and a monochromator equipped with a Peltier cell and with a grating of 1800 grooves/mm. The laser light was focused on the sample surface by means of a long focal length 50X optical objective. The main protein bonds are clearly detectable in the considered samples and this give important information on the integrity and on the state of tissue components (lipids and proteins), and consequently on the occurrence of pathology. The potential application of this method for in vivo analysis is an invaluable alternative to biopsy and pathological examinations for many medical application as screening diagnostic, therapy progress examination, and surgical support.

  19. Raman and surface-enhanced Raman spectroscopy for renal condition monitoring

    NASA Astrophysics Data System (ADS)

    Li, Jingting; Li, Ming; Du, Yong; Santos, Greggy M.; Mohan, Chandra; Shih, Wei-Chuan

    2016-03-01

    Non- and minimally-invasive techniques can provide advantages in the monitoring and clinical diagnostics in renal diseases. Although renal biopsy may be useful in establishing diagnosis in several diseases, it is an invasive approach and impractical for longitudinal disease monitoring. To address this unmet need, we have developed two techniques based on Raman spectroscopy. First, we have investigated the potential of diagnosing and staging nephritis by analyzing kidney tissue Raman spectra using multivariate techniques. Secondly, we have developed a urine creatinine sensor based on surface-enhanced Raman spectroscopy with performance near commercial assays which require relatively laborious sample preparation and longer time.

  20. Raman spectroscopy for label-free identification of calciphylaxis.

    PubMed

    Lloyd, William R; Agarwal, Shailesh; Nigwekar, Sagar U; Esmonde-White, Karen; Loder, Shawn; Fagan, Shawn; Goverman, Jeremy; Olsen, Bjorn R; Jumlongras, Dolrudee; Morris, Michael D; Levi, Benjamin

    2015-08-01

    Calciphylaxis is a painful, debilitating, and premorbid condition, which presents as calcified vasculature and soft tissues. Traditional diagnosis of calciphylaxis lesions requires an invasive biopsy, which is destructive, time consuming, and often leads to exacerbation of the condition and infection. Furthermore, it is difficult to find small calcifications within a large wound bed. To address this need, a noninvasive diagnostic tool may help clinicians identify ectopic calcified mineral and determine the disease margin. We propose Raman spectroscopy as a rapid, point-of-care, noninvasive, and label-free technology to detect calciphylaxis mineral. Debrided calciphylactic tissue was collected from six patients and assessed by microcomputed tomography (micro-CT). Micro-CT confirmed extensive deposits in three specimens, which were subsequently examined with Raman spectroscopy. Raman spectra confirmed that deposits were consistent with carbonated apatite, consistent with the literature. Raman spectroscopy shows potential as a noninvasive technique to detect calciphylaxis in a clinical environment. PMID:26263412

  1. Raman spectroscopy for label-free identification of calciphylaxis

    PubMed Central

    Lloyd, William R.; Agarwal, Shailesh; Nigwekar, Sagar U.; Esmonde-White, Karen; Loder, Shawn; Fagan, Shawn; Goverman, Jeremy; Olsen, Bjorn R.; Jumlongras, Dolrudee; Morris, Michael D.; Levi, Benjamin

    2015-01-01

    Abstract. Calciphylaxis is a painful, debilitating, and premorbid condition, which presents as calcified vasculature and soft tissues. Traditional diagnosis of calciphylaxis lesions requires an invasive biopsy, which is destructive, time consuming, and often leads to exacerbation of the condition and infection. Furthermore, it is difficult to find small calcifications within a large wound bed. To address this need, a noninvasive diagnostic tool may help clinicians identify ectopic calcified mineral and determine the disease margin. We propose Raman spectroscopy as a rapid, point-of-care, noninvasive, and label-free technology to detect calciphylaxis mineral. Debrided calciphylactic tissue was collected from six patients and assessed by microcomputed tomography (micro-CT). Micro-CT confirmed extensive deposits in three specimens, which were subsequently examined with Raman spectroscopy. Raman spectra confirmed that deposits were consistent with carbonated apatite, consistent with the literature. Raman spectroscopy shows potential as a noninvasive technique to detect calciphylaxis in a clinical environment. PMID:26263412

  2. Ultrafast and nonlinear surface-enhanced Raman spectroscopy.

    PubMed

    Gruenke, Natalie L; Cardinal, M Fernanda; McAnally, Michael O; Frontiera, Renee R; Schatz, George C; Van Duyne, Richard P

    2016-04-21

    Ultrafast surface-enhanced Raman spectroscopy (SERS) has the potential to study molecular dynamics near plasmonic surfaces to better understand plasmon-mediated chemical reactions such as plasmonically-enhanced photocatalytic or photovoltaic processes. This review discusses the combination of ultrafast Raman spectroscopic techniques with plasmonic substrates for high temporal resolution, high sensitivity, and high spatial resolution vibrational spectroscopy. First, we introduce background information relevant to ultrafast SERS: the mechanisms of surface enhancement in Raman scattering, the characterization of plasmonic materials with ultrafast techniques, and early complementary techniques to study molecule-plasmon interactions. We then discuss recent advances in surface-enhanced Raman spectroscopies with ultrafast pulses with a focus on the study of molecule-plasmon coupling and molecular dynamics with high sensitivity. We also highlight the challenges faced by this field by the potential damage caused by concentrated, highly energetic pulsed fields in plasmonic hotspots, and finally the potential for future ultrafast SERS studies. PMID:26848784

  3. Phenotypic Profiling of Antibiotic Response Signatures in Escherichia coli Using Raman Spectroscopy

    PubMed Central

    Athamneh, A. I. M.; Alajlouni, R. A.; Wallace, R. S.; Seleem, M. N.

    2014-01-01

    Identifying the mechanism of action of new potential antibiotics is a necessary but time-consuming and costly process. Phenotypic profiling has been utilized effectively to facilitate the discovery of the mechanism of action and molecular targets of uncharacterized drugs. In this research, Raman spectroscopy was used to profile the phenotypic response of Escherichia coli to applied antibiotics. The use of Raman spectroscopy is advantageous because it is noninvasive, label free, and prone to automation, and its results can be obtained in real time. In this research, E. coli cultures were subjected to three times the MICs of 15 different antibiotics (representing five functional antibiotic classes) with known mechanisms of action for 30 min before being analyzed by Raman spectroscopy (using a 532-nm excitation wavelength). The resulting Raman spectra contained sufficient biochemical information to distinguish between profiles induced by individual antibiotics belonging to the same class. The collected spectral data were used to build a discriminant analysis model that identified the effects of unknown antibiotic compounds on the phenotype of E. coli cultures. Chemometric analysis showed the ability of Raman spectroscopy to predict the functional class of an unknown antibiotic and to identify individual antibiotics that elicit similar phenotypic responses. Results of this research demonstrate the power of Raman spectroscopy as a cellular phenotypic profiling methodology and its potential impact on antibiotic drug development research. PMID:24295982

  4. Applications of Fourier transform Raman and infrared spectroscopy in forensic sciences

    NASA Astrophysics Data System (ADS)

    Kuptsov, Albert N.

    2000-02-01

    First in the world literature comprehensive digital complementary vibrational spectra collection of polymer materials and search system was developed. Non-destructive combined analysis using complementary FT-Raman and FTIR spectra followed by cross-parallel searching on digital spectral libraries, was applied in different fields of forensic sciences. Some unique possibilities of Raman spectroscopy has been shown in the fields of examination of questioned documents, paper, paints, polymer materials, gemstones and other physical evidences.

  5. In situ cell cycle phase determination using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Oshima, Yusuke; Takenaka, Tatsuji; Sato, Hidetoshi; Furihata, Chie

    2010-02-01

    Raman spectroscopy is a powerful tool for analysis of the chemical composition in living tissue and cells without destructive processes such as fixation, immunostaining, and fluorescence labeling. Raman microspectroscopic technique enables us to obtain a high quality spectrum from a single living cell. We demonstrated in situ cell cycle analysis with Raman microspectroscopy with the excitation wavelength of 532 nm. Cell cycle phases, G0/G1 and G2/M were able to be identified in the present study. The result of in situ Raman analysis was evaluated with flow cytometry analysis. Although the Raman spectra of living cells showed complex patterns during cell cycle, several Raman bands could be useful as markers for the cell cycle identification. A single cell analysis using Raman microspectroscopy predicted a possibility to observe directly molecular dynamics intracellular molecules of proteins, lipids and nucleic acids. Our current study focused on cytoplasm region and resonant Raman signals of cytochrome c in mitochondrion, and discussed how the Raman signals from cellular components contribute to the Raman spectral changes in cell cycle change in the human living cell (lung cancer cell).

  6. [Fast discrimination of edible vegetable oil based on Raman spectroscopy].

    PubMed

    Zhou, Xiu-Jun; Dai, Lian-Kui; Li, Sheng

    2012-07-01

    A novel method to fast discriminate edible vegetable oils by Raman spectroscopy is presented. The training set is composed of different edible vegetable oils with known classes. Based on their original Raman spectra, baseline correction and normalization were applied to obtain standard spectra. Two characteristic peaks describing the unsaturated degree of vegetable oil were selected as feature vectors; then the centers of all classes were calculated. For an edible vegetable oil with unknown class, the same pretreatment and feature extraction methods were used. The Euclidian distances between the feature vector of the unknown sample and the center of each class were calculated, and the class of the unknown sample was finally determined by the minimum distance. For 43 edible vegetable oil samples from seven different classes, experimental results show that the clustering effect of each class was more obvious and the class distance was much larger with the new feature extraction method compared with PCA. The above classification model can be applied to discriminate unknown edible vegetable oils rapidly and accurately. PMID:23016334

  7. Application of Raman spectroscopy technology to studying Sudan I

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhang, Guoping; Chen, Chen

    2006-06-01

    Being an industrial dye, the Sudan I may have a toxic effect after oral intake on the body, and has recently been shown to cause cancer in rats, mice and rabbits. Because China and some other countries have detected the Sudan I in samples of the hot chilli powder and the chilli products, it is necessary to study the characteristics of this dye. As one kind of molecule scattering spectroscopy, Raman spectroscopy is characterized by the frequency excursion caused by interactions of molecules and photons. The frequency excursion reflects the margin between certain two vibrational or rotational energy states, and shows the information of the molecule. Because Raman spectroscopy can provides quick, easy, reproducible, and non-destructive analysis, both qualitative and quantitative, with no sample preparation required, Raman spectroscopy has been a particularly promising technique for analyzing the characteristics and structures of molecules, especially organic ones. Now, it has a broad application in biological, chemical, environmental and industrial applications. This paper firstly introduces Sudan I dye and the Raman spectroscopy technology, and then describes its application to the Sudan I. Secondly, the fingerprint spectra of the Sudan I are respectively assigned and analyzed in detail. Finally, the conclusion that the Raman spectroscopy technology is a powerful tool to determine the Sudan I is drawn.

  8. Applications of Raman scattering spectroscopy to halide glasses

    NASA Astrophysics Data System (ADS)

    Bendow, B.; Banerjee, P. K.; Drexhage, M. G.

    1983-04-01

    Polarized Raman scattering spectroscopy is a useful tool for investigating fundamental vibrational properties, structure and bonding, origins of IR edge absorption, and dispersion of the IR refractive index. In this paper, the application of Raman spectroscopy to halide glasses and, in particular, heavy metal fluoride glasses, is described. The spectra of the latter differ substantially from those of simple oxide, halide or chalcogenide glasses and, moreover, display a wide range of vibrational characteristics, depending on composition. In combination with infrared spectroscopy, useful guidelines can be developed for tailoring glass compositions for specific applications.

  9. Raman spectroscopy of carboranes and polycarboranesiloxanes

    SciTech Connect

    Shelnutt, J.A.

    1986-01-01

    Raman spectra of some m-carboranesiloxane polymers are compared with each other and with the spectrum of o-carborane and boron carbide. The comparisons and additional polarization studies allow the assignment of some vibrations to the icosahedral 1,7-dicarboranyl units, siloxy polymer connecting units, and substituent groups of the silicon atoms. The Raman investigation is directed toward understanding the interaction of carborane icosahedral units of boron-carbide semiconductor materials.

  10. Raman spectroscopy of fluoropolymer conformal coatings on electronic boards

    NASA Astrophysics Data System (ADS)

    Rodošek, Mirjana; Perše, Lidija Slemenik; Mihelčič, Mohor; Koželj, Matjaž; Orel, Boris; Bengű, Başak; Sunetci, Onder; Pori, Pauli; Vuk, Angela Šurca

    2014-09-01

    Fluoropolymer conformal coatings were applied to electronic boards (EBs) and cured at room temperature or 80°C. The coatings were first deposited on model substrate, i.e. aluminium alloy AA 2024 and tested for their anticorrosion properties with a potentiodynamic polarisation technique. The cathodic current densities ranged from 10-9-10-10 A/cm2, approaching the lower current limit after the addition of TiO2 nanoparticles into the formulation. Application of fluoropolymer-based formulation was performed via spray-coating deposition. Examination of the coverage of EBs under UV light, which is commonly used in industry, revealed that some components might not be entirely covered. In the search for other possible analytical tools of coverage with protective coatings, optical microscopy and confocal Raman spectroscopy were investigated.

  11. Study of spin-ordering and spin-reorientation transitions in hexagonal manganites through Raman spectroscopy

    PubMed Central

    Chen, Xiang-Bai; Hien, Nguyen Thi Minh; Han, Kiok; Nam, Ji-Yeon; Huyen, Nguyen Thi; Shin, Seong-Il; Wang, Xueyun; Cheong, S. W.; Lee, D.; Noh, T. W.; Sung, N. H.; Cho, B. K.; Yang, In-Sang

    2015-01-01

    Spin-wave (magnon) scattering, when clearly observed by Raman spectroscopy, can be simple and powerful for studying magnetic phase transitions. In this paper, we present how to observe magnon scattering clearly by Raman spectroscopy, then apply the Raman method to study spin-ordering and spin-reorientation transitions of hexagonal manganite single crystal and thin films and compare directly with the results of magnetization measurements. Our results show that by choosing strong resonance condition and appropriate polarization configuration, magnon scattering can be clearly observed, and the temperature dependence of magnon scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions. Especially, the Raman method would be very helpful for investigating the weak spin-reorientation transitions by selectively probing the magnons in the Mn3+ sublattices, while leaving out the strong effects of paramagnetic moments of the rare earth ions. PMID:26300075

  12. Study of spin-ordering and spin-reorientation transitions in hexagonal manganites through Raman spectroscopy.

    PubMed

    Chen, Xiang-Bai; Hien, Nguyen Thi Minh; Han, Kiok; Nam, Ji-Yeon; Huyen, Nguyen Thi; Shin, Seong-Il; Wang, Xueyun; Cheong, S W; Lee, D; Noh, T W; Sung, N H; Cho, B K; Yang, In-Sang

    2015-01-01

    Spin-wave (magnon) scattering, when clearly observed by Raman spectroscopy, can be simple and powerful for studying magnetic phase transitions. In this paper, we present how to observe magnon scattering clearly by Raman spectroscopy, then apply the Raman method to study spin-ordering and spin-reorientation transitions of hexagonal manganite single crystal and thin films and compare directly with the results of magnetization measurements. Our results show that by choosing strong resonance condition and appropriate polarization configuration, magnon scattering can be clearly observed, and the temperature dependence of magnon scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions. Especially, the Raman method would be very helpful for investigating the weak spin-reorientation transitions by selectively probing the magnons in the Mn(3+) sublattices, while leaving out the strong effects of paramagnetic moments of the rare earth ions. PMID:26300075

  13. Tip-enhanced Raman spectroscopy and near-field polarization

    NASA Astrophysics Data System (ADS)

    Saito, Yuika; Mino, Toshihiro; Verma, Prabhat

    2015-12-01

    Tip-enhanced Raman spectroscopy (TERS) is a powerful tool for High-resolution Raman spectroscopy. In this method, a metal coated nano-tip acts as a plasmonic antenna to enhance the originally weak Raman scattering from a nanometric volume of a sample. The technique enables to detect Raman scattering light from nano-scale area and also enhance the light intensity with combination of near-filed light and localized surface plasmon generated at a metallized tip apex. Nowadays TERS is used to investigate various nano-scale samples, for examples, carbon nanotubes, graphenes DNA and biomaterials. As the TERS developed, there is high demand to investigate the properties of near-field light e.g. polarization properties. We have analyzed the polarization properties of near-field light in TERS and successfully realized the quantitative nano-imaging by visible light.

  14. Remote cure monitoring of polymeric resins by laser Raman spectroscopy

    SciTech Connect

    Hong, K.C.; Vess, T.M.; Lyon, R.E.; Myrick, M.L.

    1993-05-01

    The validity of using Raman spectroscopy to monitor the cure chemistries of amine-cured epoxy is demonstrated by correlating NIR absorbance measurements with Raman measurements for a concentration series of bisphenol-A diglycidylether in its own reaction product with diethylamine. The intensity of a normalized Raman peak at 1240 cm{sup {minus}l}, assigned to the epoxide functionality, was found to be linearly related to the concentration of epoxide groups in the resin mixtures. Also, it is shown that the Ciba-Geigy Matrimid 5292 system can be monitored by ex-situ FT-Raman spectroscopy by observing changes in the carbonyl stretching (1773 cm{sup {minus}1}) or the C=C stretching of maleimide (1587 cm{sup {minus}1}) during the cure reaction.

  15. Raman and Infrared Spectroscopy of Pyridine under High Pressure

    SciTech Connect

    Zhuravlev, K.; Traikov, K; Dong, Z; Xie, S; Song, Y; Liu, Z

    2010-01-01

    We report the structural transitions of pyridine as a function of pressure up to 26 GPa using in situ Raman spectroscopy and infrared absorption spectroscopy. By monitoring changes in the Raman shifts in the lattice region as well as the band profiles in both Raman and IR spectra, a liquid-to-solid transition at 1 GPa followed by solid-to-solid transitions at 2, 8, 11, and 16 GPa were observed upon compression. These transitions were found to be reversible upon decompression from 22 GPa. A further chemical transformation was observed when compressed beyond 22 GPa as evidenced by the substantial and irreversible changes in the Raman and infrared spectra, which could be attributed to the destruction of the ring structure. The observed transformations in pyridine were also compared to those for benzene. The similar transition sequence with well-aligned transition pressures suggests that these isoelectronic aromatics may have similar structures and stabilities under high pressure.

  16. Monitoring the influence of antibiotic exposure using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Zemanek, Pavel; Bernatova, Silvie; Jezek, Jan; Sery, Mojmir; Jakl, Petr; Siler, Martin; Ruzicka, Filip

    2014-03-01

    Here we report on combination of the data obtained from MICs (minimum inhibitory concentrations) with infor- mation of microoragnisms fingerprint provided by Raman spectroscopy. In our feasibility study we could follow mechanisms of the bacteriostatic versus bactericidal action on biofilm-positive Staphylococcus epidermidis simply by monitoring Raman bands corresponding to DNA translating the changes introduced by selected antibiotics. The Raman spectra of Staphylococcus epidermidis treated with a bacteriostatic agent show little effect on DNA which is in contrast with the action of a bactericidal agent where decreased in dedicated Raman spectra signal strength suggests DNA fragmentation. Moreover, we demonstrate that Raman tweezers are indeed able to distinguish strains of biofilm-forming (biofilm-positive) and biofilm-negative Staphylococcus epidermidis strains using principal component analysis (PCA).

  17. Proximal and point detection of contaminated surfaces using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason A.; Christesen, Steven D.; Tripathi, Ashish; Emmons, Erik D.; Wilcox, Phillip G.; Emge, Darren K.; Pardoe, Ian J.; Fountain, Augustus W., III

    2011-11-01

    We are actively investigating the use of Raman spectroscopy for proximal standoff detection of chemicals and explosive materials on surfaces. These studies include Raman Chemical Imaging of contaminated fingerprints for forensic attribution and the assessments of commercial handheld or portable Raman instruments operating with near-infrared (IR) as well as ultraviolet (UV) laser excitation specifically developed for on-the-move reconnaissance of chemical contamination. As part of these efforts, we have measured the Raman cross sections of chemical agents, toxic industrial chemicals, and explosives from the UV to NIR. We have also measured and modeled the effect interrogation angle has on the Raman return from droplets on man-made surfaces. Realistic droplet distributions have been modeled and tested against variations in surface scan patterns and laser spot size for determining the optimum scan characteristics for detection of relevant surface contamination.

  18. Single Molecule Raman Spectroscopy Under High Pressure

    NASA Astrophysics Data System (ADS)

    Fu, Yuanxi; Dlott, Dana

    2014-06-01

    Pressure effects on surface-enhanced Raman scattering spectra of Rhdoamine 6G adsorbed on silver nanoparticle surfaces was studied using a confocal Raman microscope. Colloidal silver nanoparticles were treated with Rhodamine 6G (R6G) and its isotopically substituted partner, R6G-d4. Mixed isotopomers let us identify single-molecule spectra, since multiple-molecule spectra would show vibrational transitions from both species. The nanoparticles were embedded into a poly vinyl alcohol film, and loaded into a diamond anvil cell for the high-pressure Raman scattering measurement. Argon was the pressure medium. Ambient pressure Raman scattering spectra showed few single-molecule spectra. At moderately high pressure ( 1GPa), a surprising effect was observed. The number of sites with observable spectra decreased dramatically, and most of the spectra that could be observed were due to single molecules. The effects of high pressure suppressed the multiple-molecule Raman sites, leaving only the single-molecule sites to be observed.

  19. Single bacteria identification by Raman spectroscopy.

    PubMed

    Strola, Samy Andrea; Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne Catherine; Allier, Cédric; Espagnon, Isabelle; Jary, Dorothée; Dinten, Jean-Marc

    2014-01-01

    We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300 cm⁻¹. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24 mm². The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ~90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications. PMID:25028774

  20. Identification and discrimination of polycyclic aromatic hydrocarbons using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cloutis, Edward; Szymanski, Paul; Applin, Daniel; Goltz, Douglas

    2016-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely present throughout the Solar System and beyond. They have been implicated as a contributor to unidentified infrared emission bands in the interstellar medium, comprise a substantial portion of the insoluble organic matter in carbonaceous chondrites, are expected stable components of organic matter on Mars, and are present in a wide range of terrestrial hydrocarbons and as components of biomolecules. However, PAH structures can be very complicated, making their identification challenging. Raman spectroscopy is known to be especially sensitive to the highly polarizable C-C and C=C bonds found in PAHs, and therefore, can be a powerful tool for PAH structural and compositional elucidation. This study examined Raman spectra of 48 different PAHs to determine the degree to which Raman spectroscopy could be used to uniquely identify different species, factors that control the positions of major Raman peaks, the degree to which induced fluorescence affects the intensity of Raman peaks, its usefulness for PAH discrimination, and the effects of varying excitation wavelength on some PAH Raman spectra. It was found that the arrangement and composition of phenyl (benzene) rings, and the type and position of functional groups can greatly affect fluorescence, positions and intensities of Raman peaks associated with the PAH backbone, and the introduction of new Raman peaks. Among the functional groups found on many of the PAHs that were analyzed, only a few Raman peaks corresponding to the molecular vibrations of these groups could be clearly distinguished. Comparison of the PAH Raman spectra that were acquired with both 532 and 785 nm excitation found that the longer wavelength resulted in reduced fluorescence, consistent with previous studies.

  1. Detection of Sphingomyelin Clusters by Raman Spectroscopy.

    PubMed

    Shirota, Koichiro; Yagi, Kiyoshi; Inaba, Takehiko; Li, Pai-Chi; Murata, Michio; Sugita, Yuji; Kobayashi, Toshihide

    2016-09-01

    Sphingomyelin (SM) is a major sphingolipid in mammalian cells that forms specific lipid domains in combination with cholesterol (Chol). Using molecular-dynamics simulation and density functional theory calculation, we identified a characteristic Raman band of SM at ∼1643 cm(-1) as amide I of the SM cluster. Experimental results indicate that this band is sensitive to the hydration of SM and the presence of Chol. We showed that this amide I Raman band can be utilized to examine the membrane distribution of SM. Similarly to SM, ceramide phosphoethanolamine (CerPE) exhibited an amide I Raman band in almost the same region, although CerPE lacks three methyl groups in the phosphocholine moiety of SM. In contrast to SM, the amide I band of CerPE was not affected by Chol, suggesting the importance of the methyl groups of SM in the SM-Chol interaction. PMID:27602727

  2. Raman spectroscopy of blood in-vitro

    NASA Astrophysics Data System (ADS)

    Villanueva-Luna, A. E.; Castro-Ramos, J.; Vazquez-Montiel, S.; Flores-Gil, A.; Ortiz-Lima, C. M.; Delgado-Atencio, J. A.

    2012-03-01

    We present Raman spectra from a sample of 8 volunteers that have different type of blood. The experimental data were carried out using a 785 nm excitation laser and an ocean optics spectrometer of 6 cm-1 resolution, with a used spectral region from 1000 to 1800 cm-1. We find Raman features at 1000 and 1542 cm-1 regarded with hemoglobin and its derivatives. Also we find Raman features at 1248 and 1342 cm-1 that are now regarded with pure fibrin. In this work, we use Principal Component analysis (PCA) to determine all variations of our samples, which allows us to define a classification of the influence of the blood type. Finally, we found vibrational lines of cholesterol, glucose and triglycerides that are reported in literature.

  3. Differentiation of lipsticks by Raman spectroscopy.

    PubMed

    Salahioglu, Fatma; Went, Michael J

    2012-11-30

    Dispersive Raman spectra have been obtained using a Raman microscope and an excitation wavelength of 632.8 nm from 69 lipsticks of various colours and from a range of manufacturers without any pre-treatment of the samples. 10% of the samples were too fluorescent to give Raman spectra. 22% of the samples gave spectra which were unique to the brand and colour within the collected sample set. The remaining 68% of the samples gave spectra which could be classified into seven distinct groups. Discrimination of red lipsticks by this technique was the most difficult. The spectra of deposited lipstick samples remained unchanged over a period of a least a year. PMID:22959771

  4. Raman spectroscopy of vapors at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Laane, Jaan; Haller, Kristjan; Sakurai, Sachie; Morris, Kevin; Autrey, Daniel; Arp, Zane; Chiang, Whe-Yi; Combs, Amanda

    2003-05-01

    The most effective way to obtain high quality vapor-phase Raman spectra is to heat the samples to increase their vapor pressure. Many samples can be heated to 350 °C and higher without decomposition. We have designed a simple Raman cell to allow these high temperature studies to be carried out. The high-temperature Raman spectra of nine molecules will be presented and discussed. Most of these are non-rigid molecules containing aromatic rings for which vibrational potential energy surfaces have been determined from their spectra. Two molecules ( p-cresol and 3-methylindole) are model compounds for amino acids and their vapor-phase spectra are characteristic of environments with no hydrogen bonding.

  5. Raman Spectroscopy Analysis Of Mechanical Stress Near Cu-TSVs

    NASA Astrophysics Data System (ADS)

    De Wolf, Ingrid

    2011-09-01

    This paper discusses Raman spectroscopy measurements of stress near Cu-TSVs (Through Silicon Vias) used in 3D stacking of thinned chips. It discusses the resolution and penetration depth of the technique and the relation between the measured Raman shift and stress. Using a simple model, the various stress components near TSVs are discussed and the relation between the measured Raman shift and these stress components is analyzed. Results obtained on TSVs with nearby shallow-trench isolation, with different Cu chemistry, with and without SiO2 layer on top, and with different aspect ratio are discussed and analyzed using the simple model.

  6. Pharmaceutical Analysis from Start to Finish by Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Donahue, Michael; Smith, Wayne; Patient, Michael; Farquharson, Stuart

    2010-08-01

    During the past decade Raman spectroscopy has become a widely used analytical tool in the laboratory, process environment and on-line. This is largely due to the fact that virtually every chemical produces a unique Raman signature, sample preparation is generally not required, and analyses can be performed in 1 minute or less. This presentation will describe the value of fluorescent free and x-axis stable Raman spectra in confirming the identity of raw materials, tracking reaction kinetics during drug discovery and product synthesis, monitoring and controlling batch and continuous feed reactors, and determining product properties using chemometrics.

  7. Raman spectroscopy of polyhedral carbon nano-onions

    NASA Astrophysics Data System (ADS)

    Codorniu Pujals, Daniel; Arias de Fuentes, Olimpia; Desdín García, Luis F.; Cazzanelli, Enzo; Caputi, Lorenzo S.

    2015-09-01

    The Raman spectra of polyhedral carbon nano-onions (PCO), obtained by underwater arc discharge of graphite electrodes, are studied. While the general Raman spectrum of PCO is very similar to those of other carbon nanostructures, including spherical nano-onions, the fine structure of the G and 2D bands gives valuable information that allows using Raman spectroscopy for differentiating the PCO from other carbon structures. The interpretation of the features of the fine structure of the spectra is supported by evidences obtained by TEM.

  8. Power Budget Analysis for Waveguide-Enhanced Raman Spectroscopy.

    PubMed

    Wang, Zilong; Pearce, Stuart J; Lin, Yung-Chun; Zervas, Michalis N; Bartlett, Philip N; Wilkinson, James S

    2016-08-01

    Waveguide-enhanced Raman spectroscopy (WERS) is emerging as an attractive alternative to plasmonic surface-enhanced Raman spectroscopy approaches as it can provide more reproducible quantitative spectra on a robust chip without the need for nanostructured plasmonic materials. Realizing portable WERS systems with high sensitivity using low-cost laser diodes and compact spectrometers requires a detailed analysis of the power budget from laser to spectrometer chip. In this paper, we describe theoretical optimization of planar waveguides for maximum Raman excitation efficiency, demonstrate WERS for toluene on a silicon process compatible high index contrast tantalum pentoxide waveguide, measure the absolute conversion efficiency from pump power to received power in an individual Raman line, and compare this with a power budget analysis of the complete system including collection with an optical fiber and interfacing to a compact spectrometer. Optimized 110 nm thick Ta2O5 waveguides on silica substrates excited at a wavelength of 637 nm are shown experimentally to yield overall system power conversion efficiency of ∼0.5 × 10(-12) from the pump power in the waveguide to the collected Raman power in the 1002 cm(-1) Raman line of toluene, in comparison with a calculated efficiency of 3.9 × 10(-12) Collection efficiency is dictated by the numerical and physical apertures of the spectral detection system but may be improved by further engineering the spatial and angular Raman scattering distributions. PMID:27301326

  9. Sensitive algorithm for multiple-excitation-wavelength resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Yellampalle, Balakishore; Wu, Hai-Shan; McCormick, William; Sluch, Mikhail; Martin, Robert; Ice, Robert; Lemoff, Brian E.

    2014-05-01

    Raman spectroscopy is a widely used spectroscopic technique with a number of applications. During the past few years, we explored the use of simultaneous multiple-excitation-wavelengths (MEW) in resonance Raman spectroscopy. This approach takes advantage of Raman band intensity variations across the Resonance Raman spectra obtained from two or more excitation wavelengths. Amplitude variations occur between corresponding Raman bands in Resonance Raman spectra due to complex interplay of resonant enhancement, self-absorption and laser penetration depth. We have developed a very sensitive algorithm to estimate concentration of an analyte from spectra obtained using the MEW technique. The algorithm uses correlations and least-square minimization approach to calculate an estimate for the concentration. For two or more excitation wavelengths, measured spectra were stacked in a two dimensional matrix. In a simple realization of the algorithm, we approximated peaks in the ideal library spectra as triangles. In this work, we present the performance of the algorithm with measurements obtained from a dual-excitation-wavelength Resonance Raman sensor. The novel sensor, developed at WVHTCF, detects explosives from a standoff distance. The algorithm was able to detect explosives with very high sensitivity even at signal-to-noise ratios as low as ~1.6. Receiver operating characteristics calculated using the algorithm showed a clear benefit in using the dual-excitation-wavelength technique over single-excitation-wavelength techniques. Variants of the algorithm that add more weight to amplitude variation information showed improved specificity to closely resembling spectra.

  10. Fiber-optic Raman Spectroscopy of Joint Tissues

    PubMed Central

    Esmonde-White, Karen A.; Esmonde-White, Francis W.L.; Morris, Michael D.

    2011-01-01

    In this study, we report adaptation of Raman spectroscopy for arthroscopy of joint tissues using a custom-built fiber optic probe. Differentiation of healthy and damaged tissue or examination of subsurface tissue, such as subchondral bone, is a challenge in arthroscopy because visual inspection may not provide sufficient contrast. Discrimination of healthy versus damaged tissue may be improved by incorporating point spectroscopy or hyperspectral imaging into arthroscopy where contrast is based on molecular structure or chemical composition. Articular joint surfaces of knee cadaveric human tissue and tissue phantoms were examined using a custom-designed Raman fiber optic probe. Fiber-optic Raman spectra were compared against reference spectra of cartilage, subchondral bone and cancellous bone collected using Raman microspectroscopy. In fiber-optic Raman spectra of the articular surface, there was an effect of cartilage thickness on recovery of signal from subchondral bone. At sites with intact cartilage, the bone mineralization ratio decreased but there was a minimal effect in the bone mineral chemistry ratios. Tissue phantoms were prepared as experimental models of the osteochondral interface. Raman spectra of tissue phantoms suggested that optical scattering of cartilage has a large effect on the relative cartilage and bone signal. Finite element analysis modeling of light fluence in the osteochondral interface confirmed experimental findings in human cadaveric tissue and tissue phantoms. These first studies demonstrate proof of principle for Raman arthroscopic measurement of joint tissues and provide a basis for future clinical or animal model studies. PMID:21359366

  11. Surface and waveguide collection of Raman emission in waveguide-enhanced Raman spectroscopy.

    PubMed

    Wang, Zilong; Zervas, Michalis N; Bartlett, Philip N; Wilkinson, James S

    2016-09-01

    We demonstrate Raman spectroscopy on a high index thin film tantalum pentoxide waveguide and compare collection of Raman emission from the waveguide end with that from the waveguide surface. Toluene was used as a convenient model analyte, and a 40-fold greater signal was collected from the waveguide end. Simulations of angular and spatial Raman emission distributions showed good agreement with experiments, with the enhancement resulting from efficient collection of power from dipoles near the surface into the high-index waveguide film and substrate, combined with long interaction length. The waveguide employed was optimized at the excitation wavelength but not at emission wavelengths, and full optimization is expected to lead to enhancements comparable to surface-enhanced Raman spectroscopy in robust low-cost metal-free and nanostructure-free chips. PMID:27607994

  12. The substrate matters in the Raman spectroscopy analysis of cells

    NASA Astrophysics Data System (ADS)

    Mikoliunaite, Lina; Rodriguez, Raul D.; Sheremet, Evgeniya; Kolchuzhin, Vladimir; Mehner, Jan; Ramanavicius, Arunas; Zahn, Dietrich R. T.

    2015-08-01

    Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research.

  13. The substrate matters in the Raman spectroscopy analysis of cells

    PubMed Central

    Mikoliunaite, Lina; Rodriguez, Raul D.; Sheremet, Evgeniya; Kolchuzhin, Vladimir; Mehner, Jan; Ramanavicius, Arunas; Zahn, Dietrich R.T.

    2015-01-01

    Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research. PMID:26310910

  14. Dengue blood analysis by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rehman, A.; Anwar, S.; Firdous, S.; Ahmed, M.; Rasheed, R.; Nawaz, M.

    2012-06-01

    In this work Raman spectra of normal and dengue infected serum and whole blood were analyzed. In normal whole blood and serum characteristic peaks were observed when excited at 442 and 532 nm. In dengue whole blood and serum all peaks found to be blue shifted with reduced Raman intensity. Dengue whole blood and serum shows two peaks at 1614 and 1750 cm-1 which are due to presence of Immunoglobulin antibodies IgG and IgM. Whole study provides a route of information for diagnosis of dengue viral infection.

  15. Metallized Capillaries as Probes for Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Pelletier, Michael

    2003-01-01

    A class of miniature probes has been proposed to supplant the fiber-optic probes used heretofore in some Raman and fluorescence spectroscopic systems. A probe according to the proposal would include a capillary tube coated with metal on its inside to make it reflective. A microlens would be hermetically sealed onto one end of the tube. A spectroscopic probe head would contain a single such probe, which would both deliver laser light to a sample and collect Raman or fluorescent light emitted by the sample.

  16. Two-dimensional Raman-terahertz spectroscopy of water

    PubMed Central

    Savolainen, Janne; Ahmed, Saima; Hamm, Peter

    2013-01-01

    Two-dimensional Raman-terahertz (THz) spectroscopy is presented as a multidimensional spectroscopy directly in the far-IR regime. The method is used to explore the dynamics of the collective intermolecular modes of liquid water at ambient temperatures that emerge from the hydrogen-bond networks water forming. Two-dimensional Raman-THz spectroscopy interrogates these modes twice and as such can elucidate couplings and inhomogeneities of the various degrees of freedoms. An echo in the 2D Raman-THz response is indeed identified, indicating that a heterogeneous distribution of hydrogen-bond networks exists, albeit only on a very short 100-fs timescale. This timescale appears to be too short to be compatible with more extended, persistent structures assumed within a two-state model of water. PMID:24297930

  17. Femtosecond broadband stimulated Raman spectroscopy: Apparatus and methods

    PubMed Central

    McCamant, David W.; Kukura, Philipp; Yoon, Sangwoon; Mathies, Richard A.

    2005-01-01

    The laser, detection system, and methods that enable femtosecond broadband stimulated Raman spectroscopy (FSRS) are presented in detail. FSRS is a unique tool for obtaining high time resolution (<100 fs) vibrational spectra with an instrument response limited frequency resolution of <10 cm–1. A titanium:Sapphire-based laser system produces the three different pulses needed for FSRS: (1) A femtosecond visible actinic pump that initiates the photochemistry, (2) a narrow bandwidth picosecond Raman pump that provides the energy reservoir for amplification of the probe, and (3) a femtosecond continuum probe that is amplified at Raman resonances shifted from the Raman pump. The dependence of the stimulated Raman signal on experimental parameters is explored, demonstrating the expected exponential increase in Raman intensity with concentration, pathlength, and Raman pump power. Raman spectra collected under different electronic resonance conditions using highly fluorescent samples highlight the fluorescence rejection capabilities of FSRS. Data are also presented illustrating our ability: (i) To obtain spectra when there is a large transient absorption change by using a shifted excitation difference technique and (ii) to obtain high time resolution vibrational spectra of transient electronic states. PMID:17183413

  18. Characterization of uranium tetrafluoride (UF4) with Raman spectroscopy

    DOE PAGESBeta

    Villa-Aleman, Eliel; Wellons, Matthew S.

    2016-03-22

    The Raman spectrum of uranium tetrafluoride (UF4) is unambiguously characterized with multiple Raman excitation laser sources for the first time. Across different laser excitation wavelengths, UF4 demonstrates 16 distinct Raman bands within the 50-400 cm-1 region. The observed Raman bands are representative of various F-F vibrational modes. UF4 also shows intense fluorescent bands in the 325 – 750 nm spectral region. Comparison of the UF4 spectrum with the ZrF4 spectrum, its crystalline analog, demonstrates a similar Raman band structure consistent with group theory predictions for expected Raman bands. Additionally, a demonstration of combined scanning electron microscopy (SEM) and in situmore » Raman spectroscopy microanalytical measurements of UF4 particulates shows that despite the inherent weak intensity of Raman bands, identification and characterization are possible for micron-sized particulates with modern instrumentation. The published well characterized UF4 spectrum is extremely relevant to nuclear materials and nuclear safeguard applications.« less

  19. Characterization of uranium tetrafluoride (UF 4 ) with Raman spectroscopy

    DOE PAGESBeta

    Villa-Aleman, Eliel; Wellons, Matthew S.

    2016-03-22

    The Raman spectrum of uranium tetrafluoride (UF4) is unambiguously characterized with multiple Raman excitation laser sources for the first time. Across different laser excitation wavelengths, UF4 demonstrates 16 distinct Raman bands within the 50-400 cm-1 region. The observed Raman bands are representative of various F-F vibrational modes. UF4 also shows intense fluorescent bands in the 325 – 750 nm spectral region. Comparison of the UF4 spectrum with the ZrF4 spectrum, its crystalline analog, demonstrates a similar Raman band structure consistent with group theory predictions for expected Raman bands. Additionally, a demonstration of combined scanning electron microscopy (SEM) and in situmore » Raman spectroscopy microanalytical measurements of UF4 particulates shows that despite the inherent weak intensity of Raman bands, identification and characterization are possible for micron-sized particulates with modern instrumentation. The published well characterized UF4 spectrum is extremely relevant to nuclear materials and nuclear safeguard applications.« less

  20. Understanding the application of Raman spectroscopy to the detection of traces of life.

    PubMed

    Marshall, Craig P; Edwards, Howell G M; Jehlicka, Jan

    2010-03-01

    Investigating carbonaceous microstructures and material in Earth's oldest sedimentary rocks is an essential part of tracing the origins of life on our planet; furthermore, it is important for developing techniques to search for traces of life on other planets, for example, Mars. NASA and ESA are considering the adoption of miniaturized Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for fossil or extant biomolecules. Recently, Raman spectroscopy has been used to infer a biological origin of putative carbonaceous microfossils in Early Archean rocks. However, it has been demonstrated that the spectral signature obtained from kerogen (of known biological origin) is similar to spectra obtained from many poorly ordered carbonaceous materials that arise through abiotic processes. Yet there is still confusion in the literature as to whether the Raman spectroscopy of carbonaceous materials can indeed delineate a signature of ancient life. Despite the similar nature in spectra, rigorous structural interrogation between the thermal alteration products of biological and nonbiological organic materials has not been undertaken. Therefore, we propose a new way forward by investigating the second derivative, deconvolution, and chemometrics of the carbon first-order spectra to build a database of structural parameters that may yield distinguishable characteristics between biogenic and abiogenic carbonaceous material. To place Raman spectroscopy as a technique to delineate a biological origin for samples in context, we will discuss what is currently accepted as a spectral signature for life; review Raman spectroscopy of carbonaceous material; and provide a historical overview of Raman spectroscopy applied to Archean carbonaceous materials, interpretations of the origin of the ancient carbonaceous material, and a future way forward for Raman spectroscopy. PMID:20402584

  1. Surface enhanced Raman spectroscopy of neurotransmitters

    NASA Astrophysics Data System (ADS)

    McGlashen, Michael L.; Davis, Kevin L.; Morris, Michael D.

    1989-10-01

    The surface-enhanced Raman spectra (SERS) of neurotransmitters in biological matrices and synthetic solutions are described. The effects of protein adsorption on cathecholamine SERS intensity are discussed. Techniques for obtaining dopamine SERS spectra in cerebrospinal fluid and rat brain dialysate are demonstrated. Preliminary SERS of histamine and tel-methylhistamine are presented.

  2. Raman spectroscopy of garnet-group minerals

    USGS Publications Warehouse

    Mingsheng, P.; Mao, Ho-kwang; Dien, L.; Chao, E.C.T.

    1994-01-01

    The Raman spectra of the natural end members of the garnet-group minerals, which include pyrope, almandine and spessarite of Fe-Al garnet series and grossularite, andradite and uvarovite of Ca-Fe garnet series, have been studied. Measured Raman spectra of these minerals are reasonably and qualitatively assigned to the internal modes, translational and rotatory modes of SiO4 tetrahedra, as well as the translational motion of bivalent cations in the X site. The stretch and rotatory Alg modes for the Fe-Al garnet series show obvious Raman shifts as compared with those for the Ca-Fe garnet series, owing to the cations residing in the X site connected with SiO4 tetrahedra by sharing the two edges. The Raman shifts of all members within either of the series are attributed mainly to the properties of cations in the X site for the Fe-Al garnet series and in the Y site for the Ca-Fe garnet series. ?? 1994 Institute of Geochemistry, Chinese Academy of Sciences.

  3. Resonance Raman Spectroscopy of Beta-Carotene and Lycopene: A Physical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Hoskins, L. C.

    1984-01-01

    Discusses the theory of resonance Raman (RR) spectroscopy as it applies to beta-carotene and lycopene pigments (found in tomatoes and carrots, respectively). Also discusses an experiment which demonstrates the theoretical principles involved. The experiment has been tested over a three-year period and has received excellent acceptance by physical…

  4. Trace vapour detection at room temperature using Raman spectroscopy.

    PubMed

    Chou, Alison; Radi, Babak; Jaatinen, Esa; Juodkazis, Saulius; Fredericks, Peter M

    2014-04-21

    A miniaturized flow-through system consisting of a gold coated silicon substrate based on enhanced Raman spectroscopy has been used to study the detection of vapour from model explosive compounds. The measurements show that the detectability of the vapour molecules at room temperature depends sensitively on the interaction between the molecule and the substrate. The results highlight the capability of a flow system combined with Raman spectroscopy for detecting low vapour pressure compounds with a limit of detection of 0.2 ppb as demonstrated by the detection of bis(2-ethylhexyl)phthalate, a common polymer additive emitted from a commercial polyvinyl chloride (PVC) tubing at room temperature. PMID:24588003

  5. Review on the Raman spectroscopy of different types of layered materials

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Tan, Qing-Hai; Wu, Jiang-Bin; Shi, Wei; Tan, Ping-Heng

    2016-03-01

    Two-dimensional layered materials, such as graphene and transition metal dichalcogenides (TMDs), have been under intensive investigation. The rapid progress of research on graphene and TMDs is now stimulating the exploration of different types of layered materials (LMs). Raman spectroscopy has shown its great potential in the characterization of layer numbers, interlayer coupling and layer-stacking configurations and will benefit the future explorations of other LMs. Lattice vibrations or Raman spectra of many LMs in bulk have been discussed since the 1960s. However, different results were obtained because of differences or limitations in the Raman instruments at early stages. The developments of modern Raman spectroscopy now allow us to revisit the Raman spectra of these LMs under the same experimental conditions. Moreover, to the best of our knowledge, there were limitations in detailed reviews on the Raman spectra of these different LMs. Here, we provide a review on Raman spectra of various LMs, including semiconductors, topological insulators, insulators, semi-metals and superconductors. We firstly introduce a unified method based on symmetry analysis and polarization measurements to assign the observed Raman modes and characterize the crystal structure of different types of LMs. Then, we revisit and update the positions and assignments of vibration modes by re-measuring the Raman spectra of different types of LMs and by comparing our results to those reported in previous papers. We apply the recent advances on the interlayer vibrations of graphene and TMDs to these various LMs and obtain their shear modulus. The observation of the shear modes of LMs in bulk facilitates an accurate and fast characterization of layer numbers during preparation processes in the future by a robust layer-number dependency on the frequencies of the shear modes. We also summarize the recent advances on the layer-stacking dependence on the intensities of interlayer shear vibrations

  6. Condition Assessment of Kevlar Composite Materials Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

    2007-01-01

    This viewgraph presentation includes the following main concepts. Goal: To evaluate Raman spectroscopy as a potential NDE tool for the detection of stress rupture in Kevlar. Objective: Test a series of strand samples that have been aged under various conditions and evaluate differences and trends in the Raman response. Hypothesis: Reduction in strength associated with stress rupture may manifest from changes in the polymer at a molecular level. If so, than these changes may effect the vibrational characteristics of the material, and consequently the Raman spectra produced from the material. Problem Statement: Kevlar composite over-wrapped pressure vessels (COPVs) on the space shuttles are greater than 25 years old. Stress rupture phenomena is not well understood for COPVs. Other COPVs are planned for hydrogen-fueled vehicles using Carbon composite material. Raman spectroscopy is being explored as an non-destructive evaluation (NDE) technique to predict the onset of stress rupture in Kevlar composite materials. Test aged Kevlar strands to discover trends in the Raman response. Strength reduction in Kevlar polymer will manifest itself on the Raman spectra. Conclusions: Raman spectroscopy has shown relative changes in the intensity and FWHM of the 1613 cm(exp -1) peak. Reduction in relative intensity for creep, fleet leader, and SIM specimens compared to the virgin strands. Increase in FWHM has been observed for the creep and fleet leader specimens compared to the virgin strands. Changes in the Raman spectra may result from redistributing loads within the material due to the disruption of hydrogen bonding between crystallites or defects in the crystallites from aging the Kevlar strands. Peak shifting has not been observed to date. Analysis is ongoing. Stress measurements may provide a tool in the short term.

  7. Kerr-gated picosecond Raman spectroscopy and Raman photon migration of equine bone tissue with 400-nm excitation

    NASA Astrophysics Data System (ADS)

    Morris, Michael D.; Goodship, Allen E.; Draper, Edward R. C.; Matousek, Pavel; Towrie, Michael; Parker, Anthony W.

    2004-07-01

    We show that Raman spectroscopy with visible lasers, even in the deep blue is possible with time-gated Raman spectroscopy. A 4 picosec time gate allows efficient fluorescence rejection, up to 1000X, and provides almost background-free Raman spectra with low incident laser power. The technology enables spectroscopy with better than 10X higher scattering efficiency than is possible with the NIR (785 nm and 830 nm) lasers that are conventionally used. Raman photon migration is shown to allow depth penetration. We show for the first time that Kerr-gated Raman spectra of bone tissue with blue laser excitation enables both fluorescence rejection and depth penetration.

  8. Simulated Raman correlation spectroscopy for quantifying nucleic acid-silver composites

    NASA Astrophysics Data System (ADS)

    Freeman, Lindsay M.; Smolyaninov, Alexei; Pang, Lin; Fainman, Yeshaiahu

    2016-03-01

    Plasmonic devices are of great interest due to their ability to confine light to the nanoscale level and dramatically increase the intensity of the electromagnetic field, functioning as high performance platforms for Raman signal enhancement. While Raman spectroscopy has been proposed as a tool to identify the preferential binding sites and adsorption configurations of molecules to nanoparticles, the results have been limited by the assumption that a single binding site is responsible for molecular adsorption. Here, we develop the simulated Raman correlation spectroscopy (SRCS) process to determine which binding sites of a molecule preferentially bind to a plasmonic material and in what capacity. We apply the method to the case of nucleic acids binding to silver, discovering that multiple atoms are responsible for adsorption kinetics. This method can be applied to future systems, such as to study the molecular orientation of adsorbates to films or protein conformation upon adsorption.

  9. Simulated Raman correlation spectroscopy for quantifying nucleic acid-silver composites

    PubMed Central

    Freeman, Lindsay M.; Smolyaninov, Alexei; Pang, Lin; Fainman, Yeshaiahu

    2016-01-01

    Plasmonic devices are of great interest due to their ability to confine light to the nanoscale level and dramatically increase the intensity of the electromagnetic field, functioning as high performance platforms for Raman signal enhancement. While Raman spectroscopy has been proposed as a tool to identify the preferential binding sites and adsorption configurations of molecules to nanoparticles, the results have been limited by the assumption that a single binding site is responsible for molecular adsorption. Here, we develop the simulated Raman correlation spectroscopy (SRCS) process to determine which binding sites of a molecule preferentially bind to a plasmonic material and in what capacity. We apply the method to the case of nucleic acids binding to silver, discovering that multiple atoms are responsible for adsorption kinetics. This method can be applied to future systems, such as to study the molecular orientation of adsorbates to films or protein conformation upon adsorption. PMID:27010074

  10. Raman spectroscopy for bacterial identification and characterization

    NASA Astrophysics Data System (ADS)

    Bernatová, Silvie; Samek, Ota; Pilát, Zdeněk.; Šerý, Mojmír.; Ježek, Jan; Krzyžánek, Vladislav; Zemánek, Pavel; Ružička, Filip

    2012-01-01

    The main goal of our investigation is to use Raman tweezers technique so that the responce of Raman scattering on microorganisms suspended in liquid media (bacteria, algae and yeast cells in microfluidic chips) can be used to identify different species. The investigations presented here include identification of different bacteria strains (biofilm-positive and biofilm-negative) and yeast cells by using principal component analysis (PCA). The main driving force behind our investigation was a common problem in the clinical microbiology laboratory - how to distinguish between contaminant and invasive isolates. Invasive bacterial/yeast isolates can be assumed to form a biofilm, while isolates which do not form a biofilm can be treated as contaminant. Thus, the latter do not represent an important virulence factor.

  11. Novel developments in laser diode Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Claps, Ricardo Javier

    2000-11-01

    This thesis presents the last developments of a laser diode Raman spectrometer for gases, gas flows and vapors, at medium-low pressures. Results are shown for atmospheric gases under STP conditions, and also gas flows from nozzles in subsonic-sonic regimes. The system is unique in that it uses a high power laser diode passively locked by an external grating cavity in Littman/Metcalf configuration, with side-band modes suppressed by 1:10-5, and a reduced bandwidth of <500MHz. The use of Rb vapor cells as notch filters with unprecedented narrow bandwidth (<7 cm-1), allow to collect Stokes and a-Stokes rotational Raman spectra simultaneously. The spectrometer is used to perform studies of thermodynamic equilibrium of gas flows; further studies of samples seeded in the flow (alkali- halides) are discussed, together with potential applications for environmental and industrial monitoring.

  12. Raman and optical spectroscopy of eumelanin films

    NASA Astrophysics Data System (ADS)

    Capozzi, V.; Perna, G.; Gallone, A.; Biagi, P. F.; Carmone, P.; Fratello, A.; Guida, G.; Zanna, P.; Cicero, R.

    2005-06-01

    Melanin obtained from the liver of Rana esculenta L., was isolated from melanosomes and deposited as thin film on quartz substrate, in order to perform Raman, absorption and photoluminescence measurements at room temperature. The Raman spectrum was analysed by considering the contribution of the vibrational modes from different functional groups of the melanin structure. The absorption and photoluminescence measurements support the model that melanin consists of nano-aggregates of oligomeric structures rather than extended heteropolymer. An optical gap value of about 0.6 eV was estimated by considering the Tauc model. The largest size group of clusters mainly contribute to determine the optical gap value, whereas the PL emission is due to groups of clusters which are selectively pumped.

  13. Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Galván, Ismael; Jorge, Alberto; Solano, Francisco; Wakamatsu, Kazumasa

    2013-06-01

    We characterize for the first time the vibrational state of natural pheomelanin using Raman spectroscopy and model pigment synthesized from 5-S-cysteinyldopa. The shape of the Raman spectrum was very different from that of eumelanin. Four Raman bands were visible in the 500-2000 cm-1 wavenumber region about 500, 1150, 1490 and 2000 cm-1, which we assigned to the out-of-plane deformation and the stretching vibration of the phenyl rings, to the stretching vibration of C-N bonds or the stretching and wagging vibration of CH2, and to overtone or combination bands. Interestingly, we also show that the Raman spectrum of synthetic trichochrome F, a pigment that may be produced along with pheomelanin during pheomelanogenesis, is different from that of pheomelanin and similar to the spectrum of eumelanin. We could detect Raman signal of both eumelanin and pheomelanin in feathers and hairs where both pigments simultaneously occur without the need of isolating the pigment. This indicates that Raman spectroscopy represents a non-invasive method to detect pheomelanin and distinguish it from other pigments. This may be especially relevant to detect pheomelanin in animal skin including humans, where it has been associated with animal appearance and classification, human phototypes, prevention of skin diseases and cancer risk.

  14. Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy.

    PubMed

    Galván, Ismael; Jorge, Alberto; Solano, Francisco; Wakamatsu, Kazumasa

    2013-06-01

    We characterize for the first time the vibrational state of natural pheomelanin using Raman spectroscopy and model pigment synthesized from 5-S-cysteinyldopa. The shape of the Raman spectrum was very different from that of eumelanin. Four Raman bands were visible in the 500-2000 cm(-1) wavenumber region about 500, 1150, 1490 and 2000 cm(-1), which we assigned to the out-of-plane deformation and the stretching vibration of the phenyl rings, to the stretching vibration of C-N bonds or the stretching and wagging vibration of CH2, and to overtone or combination bands. Interestingly, we also show that the Raman spectrum of synthetic trichochrome F, a pigment that may be produced along with pheomelanin during pheomelanogenesis, is different from that of pheomelanin and similar to the spectrum of eumelanin. We could detect Raman signal of both eumelanin and pheomelanin in feathers and hairs where both pigments simultaneously occur without the need of isolating the pigment. This indicates that Raman spectroscopy represents a non-invasive method to detect pheomelanin and distinguish it from other pigments. This may be especially relevant to detect pheomelanin in animal skin including humans, where it has been associated with animal appearance and classification, human phototypes, prevention of skin diseases and cancer risk. PMID:23563634

  15. [Study on the treatment turquoise using Raman spectroscopy].

    PubMed

    Chen, Quan-li; Yuan, Xin-qiang; Chen, Jing-zhong; Qi, Li-jian

    2010-07-01

    Due to a variety of the enhancement and treatment turquoises discovered in gem markets, the identification of turquoise is becoming more and more difficult. By using laser Raman spectroscopy analysis, the characteristics of Raman spectra of the pressed and filled turquoises were studied. The results show that laser Raman spectroscopy is an effective technique to identify the enhancement and treatment turquoises and the natural ones, moreover, it's a non-destructive testing method. The Raman spectra of the enhancement and treatment turquoises are resulted mainly from the vibrational mode and frequency of water, hydroxyl units, PO4 tetrahedron and CH2 units. Besides, they have the characteristic Raman spectra peaks at 2,937, 2,883 and 1,451 cm(-1) which are attributed to the stretching vibration and the bending vibration of CH2, respectively. These characteristic Raman vibration bands, it will help to distinguish the natural turquoises and the treatment ones. The study provides a new train of thought on the rapid, accurate, and non-destructive identification of turquoise. PMID:20827971

  16. Raman spectroscopy and oral exfoliative cytology

    NASA Astrophysics Data System (ADS)

    Sahu, Aditi; Shah, Nupur; Mahimkar, Manoj; Garud, Mandavi; Pagare, Sandeep; Nair, Sudhir; Krishna, C. Murali

    2014-03-01

    Early detection of oral cancers can substantially improve disease-free survival rates. Ex vivo and in vivo Raman spectroscopic (RS) studies on oral cancer have demonstrated the applicability of RS in identifying not only malignant and premalignant conditions but also cancer-field-effects: the earliest events in oral carcinogenesis. RS has also been explored for cervical exfoliated cells analysis. Exfoliated cells are associated with several advantages like non-invasive sampling, higher patient compliance, transportation and analysis at a central facility: obviating need for on-site instrumentation. Thus, oral exfoliative cytology coupled with RS may serve as a useful adjunct for oral cancer screening. In this study, exfoliated cells from healthy controls with and without tobacco habits, premalignant lesions (leukoplakia and tobacco-pouch-keratosis) and their contralateral mucosa were collected using a Cytobrush. Cells were harvested by vortexing and centrifugation at 6000 rpm. The cellular yield was ascertained using Neubauer's chamber. Cell pellets were placed on a CaF2 window and Raman spectra were acquired using a Raman microprobe (40X objective) coupled HE-785 Raman spectrometer. Approximately 7 spectra were recorded from each pellet, following which pellet was smeared onto a glass slide, fixed in 95% ethanol and subjected to Pap staining for cytological diagnosis (gold standard). Preliminary PC-LDA followed by leave-one-out cross validation indicate delineation of cells from healthy and all pathological conditions. A tendency of classification was also seen between cells from contralateral, healthy tobacco and site of premalignant lesions. These results will be validated by cytological findings, which will serve as the basis for building standard models of each condition.

  17. X-ray resonant Raman spectroscopy

    SciTech Connect

    Cowan, P.L.; LeBrun, T.; Deslattes, R.D.

    1995-08-01

    X-ray resonant Raman scattering presents great promise as a high-resolution spectroscopic probe of the electronic structure of matter. Unlike other methods, the technique avoids the loss of energy resolution resulting from the lifetime broadening of short-lived core-excited states. In addition, measurements of polarization and angular anisotropies yield information on the symmetries of electronic states of atoms and molecules. We studied the L{sub 3} edge of xenon, where the lifetime broadening is a major feature of the spectra recorded previously. X-ray fluorescence spectra were taken of both the L{alpha}{sub l,2} and L{beta}{sub 2,15} peaks over a range of energies from 10 eV below the edge to 40 eV above. These spectra show the evolution of resonant Raman scattering into characteristic fluorescence as the photon energy is scanned across the edge, and confirm several features of these spectra such as asymmetries in resonant peak shapes due to the onset of the ionization continuum. These results constitute the most comprehensive study of X-ray resonant Raman scattering to date, and were submitted for publication. Studies of other cases are under way, and new instruments that would match the unique characteristics of the APS - and thus render a new range of experiments possible - are under consideration.

  18. 1064 nm FT-Raman spectroscopy for investigations of plant cell walls and other biomass materials

    PubMed Central

    Agarwal, Umesh P.

    2014-01-01

    Raman spectroscopy with its various special techniques and methods has been applied to study plant biomass for about 30 years. Such investigations have been performed at both macro- and micro-levels. However, with the availability of the Near Infrared (NIR) (1064 nm) Fourier Transform (FT)-Raman instruments where, in most materials, successful fluorescence suppression can be achieved, the utility of the Raman investigations has increased significantly. Moreover, the development of several new capabilities such as estimation of cellulose-crystallinity, ability to analyze changes in cellulose conformation at the local and molecular level, and examination of water-cellulose interactions have made this technique essential for research in the field of plant science. The FT-Raman method has also been applied to research studies in the arenas of biofuels and nanocelluloses. Moreover, the ability to investigate plant lignins has been further refined with the availability of near-IR Raman. In this paper, we present 1064-nm FT-Raman spectroscopy methodology to investigate various compositional and structural properties of plant material. It is hoped that the described studies will motivate the research community in the plant biomass field to adapt this technique to investigate their specific research needs. PMID:25295049

  19. Detection of nasopharyngeal cancer using confocal Raman spectroscopy and genetic algorithm technique

    NASA Astrophysics Data System (ADS)

    Li, Shao-Xin; Chen, Qiu-Yan; Zhang, Yan-Jiao; Liu, Zhi-Ming; Xiong, Hong-Lian; Guo, Zhou-Yi; Mai, Hai-Qiang; Liu, Song-Hao

    2012-12-01

    Raman spectroscopy (RS) and a genetic algorithm (GA) were applied to distinguish nasopharyngeal cancer (NPC) from normal nasopharyngeal tissue. A total of 225 Raman spectra are acquired from 120 tissue sites of 63 nasopharyngeal patients, 56 Raman spectra from normal tissue and 169 Raman spectra from NPC tissue. The GA integrated with linear discriminant analysis (LDA) is developed to differentiate NPC and normal tissue according to spectral variables in the selected regions of 792-805, 867-880, 996-1009, 1086-1099, 1288-1304, 1663-1670, and 1742-1752 cm-1 related to proteins, nucleic acids and lipids of tissue. The GA-LDA algorithms with the leave-one-out cross-validation method provide a sensitivity of 69.2% and specificity of 100%. The results are better than that of principal component analysis which is applied to the same Raman dataset of nasopharyngeal tissue with a sensitivity of 63.3% and specificity of 94.6%. This demonstrates that Raman spectroscopy associated with GA-LDA diagnostic algorithm has enormous potential to detect and diagnose nasopharyngeal cancer.

  20. Remote sensing of subsurface water temperature by laser Raman spectroscopy

    NASA Technical Reports Server (NTRS)

    Leonard, D. A.; Caputo, B.; Guagliardo, J. L.; Hoge, F. E.

    1980-01-01

    This paper describes experimental remote sensing of subsurface water temperature using the Raman spectroscopic technique. By the use of a pulsed laser and range gating detection techniques, Raman scattering is analyzed as a function of depth in a radar-like echo mode, and thus subsurface profiles of temperature and transmission are obtained. Experiments are described in which Raman data using polarization spectroscopy has been obtained from a ship as a function of depth in ocean water near Grand Bahama Island. A spectral temperature accuracy of + or - 1 C has been obtained from this data in the first two optical attenuation lengths. Raman data obtained from ocean water using the NASA airborne oceanographic lidar is also presented.

  1. [Measurement of nasopharyngeal carcinoma tissue ex vivo by Raman spectroscopy].

    PubMed

    Huang, Wei; Pan, Jian-ji; Chen, Rong; Li, Yong-zeng; Feng, Shang-yuan; Xie, Shu-sen; Zeng, Hai-shan

    2009-05-01

    Raman spectroscopy has shown its potential and advantages in detecting molecular changes associated with tissue pathology, which makes it possible to diagnose with optical methods non-invasively and real-time. A compact and rapid near-infrared (NIR)Raman system was developed using 785 nm diode laser, volume phase technology (VPT)holographic grating system and NIR intensified charge-coupled device (CCD)with a specially designed Raman fibre probe which can effectively reduce the interference of fluorescence and Rayleigh scattering, maximize the ability of Raman collection as well as correct the image aberration of a planar grating diffraction. Adopting this method, signal-to-noise ratio has been greatly improved and human tissue signals can be acquired in a short time. Raman signals from fat and musculature of fresh pork were measured and referenced for further optimization, then Raman spectra of nasopharyngeal carcinoma in vitro and the effect of storage time on them were measured in 1-5 s and discussed. The sensitivities and performance of the system will be further enhanced and more Raman data will be acquired and compared between normal and cancerous nasopharyngeal tissue, expecting to discover the statistical characteristics, which will benefit the diagnosis and treatment of early nasopharyngeal carcinoma or other tumors. PMID:19650477

  2. Fluorescence suppression using micro-scale spatially offset Raman spectroscopy.

    PubMed

    Conti, Claudia; Botteon, Alessandra; Colombo, Chiara; Realini, Marco; Matousek, Pavel

    2016-09-21

    We present a new concept of fluorescence suppression in Raman microscopy based on micro-spatially offset Raman spectroscopy which is applicable to thin stratified turbid (diffusely scattering) matrices permitting the retrieval of the Raman signals of sublayers below intensely fluorescing turbid over-layers. The method is demonstrated to yield good quality Raman spectra with dramatically suppressed fluorescence backgrounds enabling the retrieval of Raman sublayer signals even in situations where conventional Raman microscopy spectra are fully overwhelmed by intense fluorescence. The concept performance was studied theoretically using Monte Carlo simulations indicating the potential of up to an order or two of magnitude suppression of overlayer fluorescence backgrounds relative to the Raman sublayer signals. The technique applicability was conceptually demonstrated on layered samples involving paints, polymers and stones yielding fluorescence suppression factors between 12 to above 430. The technique has potential applications in a number of analytical areas including cultural heritage, archaeology, polymers, food, pharmaceutical, biological, biomedical, forensics and catalytic sciences and quality control in manufacture. PMID:27338230

  3. Raman-spectroscopy-based biosensing for applications in ophthalmology

    NASA Astrophysics Data System (ADS)

    Rusciano, Giulia; Capriglione, Paola; Pesce, Giuseppe; Zito, Gianluigi; Del Prete, Antonio; Cennamo, Giovanni; Sasso, Antonio

    2013-05-01

    Cell-based biosensors rely on the detection and identification of single cells as well as monitoring of changes induced by interaction with drugs and/or toxic agents. Raman spectroscopy is a powerful tool to reach this goal, being non-destructive analytical technique, allowing also measurements of samples in aqueous environment. In addition, micro-Raman measurements do not require preliminary sample preparation (as in fluorescence spectroscopy), show a finger-print spectral response, allow a spatial resolution below typical cell sizes, and are relatively fast (few s or even less). All these properties make micro-Raman technique particularly promising for high-throughput on-line analysis integrated in lab-on-a-chip devices. Herein, we demonstrate some applications of Raman analysis in ophthalmology. In particular, we demonstrate that Raman analysis can provide useful information for the therapeutic treatment of keratitis caused by Acanthamoeba Castellanii (A.), an opportunistic protozoan that is widely distributed in the environment and is known to produce blinding keratitis and fatal encephalitis. In particular, by combining Raman analysis with Principal Component Analysis (PCA), we have demonstrated that is possible to distinguish between live and dead cells, enabling, therefore to establish the effectiveness of therapeutic strategies to vanquish the protozoa. As final step, we have analyzed the presence of biochemical differences in the conjunctival epithelial tissues of patients affected by keratitis with respect to healthy people. As a matter of facts, it is possible to speculate some biochemical alterations of the epithelial tissues, rendering more favorable the binding of the protozoan. The epithelial cells were obtained by impression cytology from eyes of both healthy and keratitis-affected individuals. All the samples were analyzed by Raman spectroscopy within a few hours from cells removal from eyes. The results of this analysis are discussed.

  4. Raman spectroscopy for in-situ monitoring of electrode processes

    SciTech Connect

    Varma, R; Cook, G M; Yao, N P

    1982-04-01

    The theoretical and experimental applications of Raman spectroscopic techniques to the study of battery electrode processes are described. In particular, the potential of Raman spectroscopy as an in-situ analytical tool for the characterization of the structure and composition of electrode surface layers at electrode-electrolyte interfaces during electrolysis is examined. It is anticipated that this understanding of the battery electrode processes will be helpful in designing battery active material with improved performance. The applications of Raman spectroscopy to the in-situ study of electrode processes has been demonstrated in a few selected areas, including: (1) the anodic corrosion of lead in sulfuric acid and (2) the anodization and sulfation of tetrabasicleadsulfate in sulfuric acid. Preliminary results on the anodization of iron and on the electrochemical behavior of nickel positive-electrode active material in potassium hydroxide electrolytes are presented in the Appendix.

  5. Imaging EGFR distribution using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucas, L.; Chen, X. K.; Smith, A.; Korbelik, M.; Zeng, H.; Lee, P. W. K.; Hewitt, K. C.

    2009-02-01

    The purpose of this study is to explore the feasibility of using Surface Enhanced Raman Spectroscopy (SERS) to image the distribution of Epidermal Growth Factor Receptor (EGFR) in cells. To accomplish this task, 30 nm gold nanoparticles (AuNPs) tagged with antibodies to EGFR (1012 per ml) are incubated with cells (106 per ml) of the A431 human epidermoid carcinoma cell line and normal human bronchial epithelial (NHBE) cells. Using the 632.8 nm excitation line of a He-Ne laser, Raman spectroscopy measurements are performed using a point mapping scheme. SERS signals are observed with an overall enhancement of 4-7 orders of magnitude. Raman intensity maps of the 1480 and 1583 cm-1 peaks correlate well with the expected distribution of AuNPs and EGFR. Normal cells show little to no enhancement. The results therefore present a simple yet effective means to image EGFR over-expression.

  6. Principle, system, and applications of tip-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, MingQian; Wang, Rui; Wu, XiaoBin; Wang, Jia

    2012-08-01

    Raman spectroscopy is a powerful technique in chemical information characterization. However, this spectral method is subject to two obstacles in nano-material detection. One is diffraction limited spatial resolution, and the other is its inherent small Raman cross section and weak signaling. To resolve these problems, a new approach has been developed, denoted as tip-enhanced Raman spectroscopy (TERS). TERS is capable of high-resolution and high-sensitivity detection and demonstrated to be a promising spectroscopic and micro-topographic method to characterize nano-materials and nanostructures. In this paper, the principle and experimental system of TERS are discussed. The latest application of TERS in molecule detection, biological specimen identification, nanao-material characterization, and semi-conductor material determination with some specific experimental examples are presented.

  7. Cone penetrometer fiber optic raman spectroscopy probe assembly

    DOEpatents

    Kyle, Kevin R.; Brown, Steven B.

    2000-01-01

    A chemically and mechanically robust optical Raman spectroscopy probe assembly that can be incorporated in a cone penetrometer (CPT) for subsurface deployment. This assembly consists of an optical Raman probe and a penetrometer compatible optical probe housing. The probe is intended for in-situ chemical analysis of chemical constituents in the surrounding environment. The probe is optically linked via fiber optics to the light source and the detection system at the surface. A built-in broadband light source provides a strobe method for direct measurement of sample optical density. A mechanically stable sapphire window is sealed directly into the side-wall of the housing using a metallic, chemically resistant, hermetic seal design. This window permits transmission of the interrogation light beam and the resultant signal. The spectroscopy probe assembly is capable of accepting Raman, Laser induced Fluorescence, reflectance, and other optical probes with collimated output for CPT deployment.

  8. Cone penetrometer fiber optic Raman spectroscopy probe assembly

    SciTech Connect

    Kyle, K.R.; Brown, S.B.

    2000-01-25

    A chemically and mechanically robust optical Raman spectroscopy probe assembly is described that can be incorporated in a cone penetrometer (CPT) for subsurface deployment. This assembly consists of an optical Raman probe and a penetrometer compatible optical probe housing. The probe is intended for in-situ chemical analysis of chemical constituents in the surrounding environment. The probe is optically linked via fiber optics to the light source and the detection system at the surface. A built-in broadband light source provides a strobe method for direct measurement of sample optical density. A mechanically stable sapphire window is sealed directly into the side-wall of the housing using a metallic, chemically resistant, hermetic seal design. This window permits transmission of the interrogation light beam and the resultant signal. The spectroscopy probe assembly is capable of accepting Raman, Laser induced Fluorescence, reflectance, and other optical probes with collimated output for CPT deployment.

  9. Stress Analysis of SiC MEMS Using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ness, Stanley J.; Marciniak, M. A.; Lott, J. A.; Starman, L. A.; Busbee, J. D.; Melzak, J. M.

    2003-03-01

    During the fabrication of Micro-Electro-Mechanical Systems (MEMS), residual stress is often induced in the thin films that are deposited to create these systems. These stresses can cause the device to fail due to buckling, curling, or fracture. Industry is looking for ways to characterize the stress during the deposition of thin films in order to reduce or eliminate device failure. Micro-Raman spectroscopy has been successfully used to characterize poly-Si MEMS devices made with the MUMPS® process. Raman spectroscopy was selected because it is nondestructive, fast and has the potential for in situ stress monitoring. This research attempts to use Raman spectroscopy to analyze the stress in SiC MEMS made with the MUSiC® process. Raman spectroscopy is performed on 1-2-micron-thick SiC thin films deposited on silicon, silicon nitride, and silicon oxide substrates. The most common poly-type of SiC found in thin film MEMS made with the MUSiC® process is 3C-SiC. Research also includes baseline spectra of 6H, 4H, and 15R poly-types of bulk SiC.

  10. FT-Raman spectroscopy of lichen species from the Antarctic

    NASA Astrophysics Data System (ADS)

    Holder, J. M.; Edwards, H. G. M.; Wynn-Williams, D. D.

    1998-06-01

    In this investigation, FT-Raman spectroscopy has been utilized to characterize pigments and chemicals produced by Antarctic lichens, which have been exposed to increasing levels of UV-B radiation and other environmental conditions. The presence of calcium oxalate in some lichen species has also been confirmed spectroscopically.