WorldWideScience

Sample records for anti-stokes raman spectroscopic

  1. Coherent anti-Stokes Raman spectroscopic measurement of air entrainment in argon plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Fincke, J.R.; Rodriquez, R.; Pentecost, C.G.

    1990-01-01

    The concentration and temperature of air entrained into an argon plasma jet has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition to turbulence occurs, air is rapidly entrained into the jet core. The location of the transition region is thought to be driven by the rapid cooling of the jet and the resulting increase in Reynolds number. 8 refs., 6 figs.

  2. Raman optical activity spectroscopy by visible-excited coherent anti-Stokes Raman scattering.

    Science.gov (United States)

    Hiramatsu, Kotaro; Leproux, Philippe; Couderc, Vincent; Nagata, Takashi; Kano, Hideaki

    2015-09-01

    We developed a Raman optical activity (ROA) spectroscopic system with visible-excited coherent anti-Stokes Raman scattering (CARS). A supercontinuum within the visible region was generated with a photonic crystal fiber pumped with both 532 and 1064 nm excitation, generating a multiplexed CARS-ROA spectrum covering the whole fingerprint region. In visible excitation, the CARS-ROA spectrum of (-)-β-pinene shows a higher contrast ratio of the chirality-induced signal to the achiral background than that of the previously reported near-infrared CARS-ROA spectrum.

  3. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds.

    Science.gov (United States)

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-11-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp(3) vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.

  4. Investigation of enhanced forward and backward anti-stokes Raman signals in lithium niobate waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Da; Hong, Pengda; Ding, Yujie J., E-mail: yding300@gmail.com [Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Liu, Zhaojun; Wang, Lei [Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); School of Information Science and Engineering, Shandong University, Jinan, Shandong 250100 (China); Hua, Ping-Rang; Zhang, De-Long [School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China)

    2015-07-07

    We have observed enhancements of the anti-Stokes Raman signals generated in lithium niobate waveguides in the forward and backward configurations by at least one order of magnitude under the pump power of the microwatt level. These output signals were measured using a single photon detector. The forward and backward propagating anti-Stokes signals exhibited different spectral features.

  5. Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source

    DEFF Research Database (Denmark)

    Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.

    2003-01-01

    A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup is demonstra......A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup...

  6. A note on two-phonon coherent anti-stokes Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y. R. [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division

    1981-01-01

    Difference-frequency mixing of two pump waves can in principle excite two coherent phonon waves via the parametric process. Finally, only when the phonon excitation is small can the nonlinear susceptibility of two-phonon coherent anti-Stokes Raman scattering be described as proportional to the product of two Raman tensors.

  7. Resonant anti-Stokes Raman scattering in single-walled carbon nanotubes

    Science.gov (United States)

    Gordeev, Georgy; Jorio, Ado; Kusch, Patryk; Vieira, Bruno G. M.; Flavel, Benjamin; Krupke, Ralph; Barros, Eduardo B.; Reich, Stephanie

    2017-12-01

    The dependence of the anti-Stokes Raman intensity on the excitation laser energy in carbon nanotubes is studied by resonant Raman spectroscopy. The complete resonant anti-Stokes and Stokes Raman profiles of the high-energy longitudinal phonon (G+) are obtained for (8,3), (7,5), (6,4), and (6,5) single chirality enriched samples. A high asymmetry between the intensity of the incoming and outgoing resonance is observed in the resonant Raman profiles. In contrast to Stokes scattering, anti-Stokes scattering is more intense at the outgoing resonance then at the incoming resonance. The resonance profiles are explained by a Raman process that includes the phonon-mediated interactions with the dark excitonic state. The chirality dependence of the Raman profiles is due to the variation in the exciton-phonon matrix elements, in agreement with tight-binding calculations. Based on the asymmetric Raman profiles we present the resonance factors for the Stokes/anti-Stokes ratios in carbon nanotubes.

  8. Epi-detection of vibrational phase contrast coherent anti-Stokes Raman scattering

    NARCIS (Netherlands)

    Garbacik, E.T.; Korterik, Jeroen P.; Otto, Cornelis; Herek, Jennifer Lynn; Offerhaus, Herman L.

    2014-01-01

    We demonstrate a system for the phase-resolved epi-detection of coherent anti-Stokes Raman scattering (CARS) signals in highly scattering and/or thick samples. With this setup, we measure the complex vibrational responses of multiple components in a thick, highly-scattering pharmaceutical tablet in

  9. Ground-state depletion for subdiffraction-limited spatial resolution in coherent anti-Stokes Raman

    NARCIS (Netherlands)

    Cleff, C.; Groß, P.; Fallnich, C.; Offerhaus, H. L.; Herek, J.; Kruse, K.; Beeker, W. P.; Lee, C. J.; Boller, K. J.

    2012-01-01

    We theoretically investigate ground-state depletion for subdiffraction-limited spatial resolution in coherent anti-Stokes Raman scattering (CARS) microscopy. We propose a scheme based on ground-state depopulation, which is achieved via a control laser light field incident prior to the CARS

  10. Rapid identification of heterogeneous mixture components with hyperspectral coherent anti-Stokes Raman scattering imaging

    NARCIS (Netherlands)

    Garbacik, E.T.; Herek, Jennifer Lynn; Otto, Cornelis; Offerhaus, Herman L.

    2012-01-01

    For the rapid analysis of complicated heterogeneous mixtures, we have developed a method to acquire and intuitively display hyperspectral coherent anti-Stokes Raman scattering (CARS) images. The imaging is performed with a conventional optical setup based around an optical parametric oscillator.

  11. Coherent anti-Stokes Raman scattering (CARS) microscopy driving the future of loaded mesoporous silica imaging

    NARCIS (Netherlands)

    Fussell, A.L.; Mah, Pei Ting; Offerhaus, Herman L.; Niemi, Sanna-Mari; Salonen, Jarno; Santos, Helder A.; Strachan, Clare

    2014-01-01

    This study reports the use of variants of coherent anti-Stokes Raman scattering (CARS) microscopy as a novel method for improved physicochemical characterization of drug-loaded silica particles. Ordered mesoporous silica is a biomaterial that can be loaded to carry a number of biochemicals,

  12. Supercontinuum generation for coherent anti- Stokes Raman scattering microscopy with photonic crystal fibers

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.

    2011-01-01

    Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectru...

  13. Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman scattering microscopy

    OpenAIRE

    Zimmerley, Maxwell; Lin, Chia-Yu; Oertel, David C.; Marsh, Jennifer M.; Ward, Jimmie L.; Potma, Eric Olaf

    2009-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is used to determine the distribution and concentration of selected compounds in intact human hair. By generating images based on ratiometric CARS contrast, quantitative concentration maps of both water and externally applied d-glycine are produced in the cortex of human hair fibers. Both water and d-glycine are found to homogeneously distribute throughout the cortical regions of the hair. The ability to selectively detect molecular agen...

  14. Protein secondary structure imaging with ultrabroadband multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy.

    Science.gov (United States)

    Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; Tokuhara, Shihomi; Naito, Satoru; Masukawa, Yoshinori; Leproux, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o

    2012-02-02

    Protein secondary structures in human hair have been studied with ultrabroadband multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The CARS peak-shift mapping method has been developed and applied to hair samples with and without treatments by chemical reduction and mechanical extension. It clearly visualizes the treatment induced changes in protein secondary structures and their spatial distributions. Using the new imaging technique, we found a multilayered structure in the human hair cortex.

  15. Revealing silent vibration modes of nanomaterials by detecting anti-Stokes hyper-Raman scattering with femtosecond laser pulses.

    Science.gov (United States)

    Zeng, Jianhua; Chen, Lei; Dai, Qiaofeng; Lan, Sheng; Tie, Shaolong

    2016-01-21

    We proposed a scheme in which normal Raman scattering is coupled with hyper-Raman scattering for generating a strong anti-Stokes hyper-Raman scattering in nanomaterials by using femtosecond laser pulses. The proposal was experimentally demonstrated by using a single-layer MoS2 on a SiO2/Si substrate, a 17 nm-thick MoS2 on an Au/SiO2 substrate and a 9 nm-thick MoS2 on a SiO2-SnO2/Ag/SiO2 substrate which were confirmed to be highly efficient for second harmonic generation. A strong anti-Stokes hyper-Raman scattering was also observed in other nanomaterials possessing large second-order susceptibilities, such as silicon quantum dots self-assembled into "coffee" rings and tubular Cu-doped ZnO nanorods. In all the cases, many Raman inactive vibration modes were clearly revealed in the anti-Stokes hyper-Raman scattering. Apart from the strong anti-Stokes hyper-Raman scattering, Stokes hyper-Raman scattering with small Raman shifts was detected during the ablation process of thick MoS2 layers. It was also observed by slightly defocusing the excitation light. The detection of anti-Stokes hyper-Raman scattering may serve as a new technique for studying the Raman inactive vibration modes in nanomaterials.

  16. Analysis of organic pollutant degradation in pulsed plasma by coherent anti-Stokes Raman spectroscopy

    International Nuclear Information System (INIS)

    Bratescu, Maria Antoneta; Hieda, Junko; Umemura, Tomonari; Saito, Nagahiro; Takai, Osamu

    2011-01-01

    The degradation of p-benzoquinone (p-BQ) in water was investigated by the coherent anti-Stokes Raman spectroscopy (CARS) method, in which the change of the anti-Stokes signal intensity corresponding to the vibrational transitions of the molecule is monitored during and after solution plasma processing (SPP). In the beginning of SPP treatment, the CARS signal intensity of the ring vibrational molecular transitions at 1233 and 1660 cm -1 increases under the influence of the electric field of the plasma, depending on the delay time between the plasma pulse and the laser firing pulse. At the same time, the plasma contributes to the degradation of p-BQ molecules by generating hydrogen and hydroxyl radicals, which decompose p-BQ into different carboxylic acids. After SPP, the CARS signal intensity of the vibrational bands of p-BQ ceased and the degradation of p-BQ was confirmed by UV-visible absorption spectroscopy and liquid chromatography analysis.

  17. Wide-Field Vibrational Phase Contrast Imaging Based on Coherent Anti-Stokes Raman Scattering Holography

    International Nuclear Information System (INIS)

    Lv Yong-Gang; Ji Zi-Heng; Dong Da-Shan; Gong Qi-Huang; Shi Ke-Bin

    2015-01-01

    We propose and implement a wide-field vibrational phase contrast detection to obtain imaging of imaginary components of third-order nonlinear susceptibility in a coherent anti-Stokes Raman scattering (CARS) microscope with full suppression of the non-resonant background. This technique is based on the unique ability of recovering the phase of the generated CARS signal based on holographic recording. By capturing the phase distributions of the generated CARS field from the sample and from the environment under resonant illumination, we demonstrate the retrieval of imaginary components in the CARS microscope and achieve background free coherent Raman imaging. (paper)

  18. Width-Increased Dual-Pump Enhanced Coherent Anti-Stokes Raman Spectroscopy (WIDECARS)

    Science.gov (United States)

    Tedder, Sarah A.; Danehy, Paul M.; Cutler, Andrew D.

    2010-01-01

    WIDECARS is a dual-pump coherent anti-Stokes Raman Spectroscopy technique that is capable of simultaneously measuring temperature and species mole fractions of N2, O2, H2, C2H4, CO, and CO2. WIDECARS is designed for measurements of all the major species (except water) in supersonic combustion flows fueled with hydrogen and hydrogen/ethylene mixtures. The two lowest rotational energy levels of hydrogen detectable by WIDECARS are H2 S(3) and H2 S(4). The detection of these lines gives the system the capability to measure temperature and species concentrations in regions of the flow containing pure hydrogen fuel at room temperature.

  19. Study of high-temperature multiplex HCl coherent anti-Stokes Raman spectroscopy spectra.

    Science.gov (United States)

    Singh, J P; Yueh, F Y; Kao, W; Cook, R L

    1993-02-20

    A feasibility study of temperature measurement with multiplex HCl coherent anti-Stokes Raman spectroscopy (CARS) is investigated. The HCl CARS spectra of a 100% HCl gas sample are recorded in a quartz sample cell placed in a furnace at 1 atm pressure and at different temperatures. The nonlinear susceptibility of HCl (chi(nr)(HCl)), which is measured with the present CARS experimental setup, is reported. The experimental spectra are fit by using a library of simulated HCl CARS spectra with a least-squares-fitting program to infer the temperature. The inferred temperatures from HCl CARS spectra are in agreement with thermocouple temperatures.

  20. Diagnostics of silane and germane radio frequency plasmas by coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Perry, Joseph W.; Shing, Y. H.; Allevato, C. E.

    1988-01-01

    In situ plasma diagnostics using coherent anti-Stokes Raman spectroscopy have shown different dissociation characteristics for GeH4 and SiH4 in radio frequency (rf) plasma-enhanced chemical vapor deposition of amorphous silicon germanium alloy (a-SiGe:H) thin films. The GeH4 dissociation rate in rf plasmas is a factor of about 3 larger than that of SiH4. Plasma diagnostics have revealed that the hydrogen dilution of the SiH4 and GeH4 mixed plasma plays a critical role in suppressing the gas phase polymerization and enhancing the GeH4 dissociation.

  1. Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Zimmerley, Maxwell; Lin, Chia-Yu; Oertel, David C.; Marsh, Jennifer M.; Ward, Jimmie L.; Potma, Eric Olaf

    2009-07-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is used to determine the distribution and concentration of selected compounds in intact human hair. By generating images based on ratiometric CARS contrast, quantitative concentration maps of both water and externally applied d-glycine are produced in the cortex of human hair fibers. Both water and d-glycine are found to homogeneously distribute throughout the cortical regions of the hair. The ability to selectively detect molecular agents in hair fibers is of direct relevance to understanding the chemical and physical mechanisms that underlie the performance of hair-care products.

  2. Rapid spectro-polarimetry to probe molecular symmetry in multiplex coherent anti-Stokes Raman scattering.

    Science.gov (United States)

    Würthwein, Thomas; Brinkmann, Maximilian; Hellwig, Tim; Fallnich, Carsten

    2017-11-21

    We present the simultaneous detection of the spectrum and the complete polarization state of a multiplex coherent anti-Stokes Raman scattering signal with a fast division-of-amplitude spectro-polarimeter. The spectro-polarimeter is based on a commercial imaging spectrograph, a birefringent wedge prism, and a segmented polarizer. Compared to the standard rotating-retarder fixed-analyzer spectro-polarimeter, only a single measurement is required and an up to 21-fold reduced acquisition time is shown. The measured Stokes parameters allow us to differentiate between vibrational symmetries and to determine the depolarization ratio ρ by data post-processing.

  3. Coherent anti-Stokes Raman scattering (CARS) detection or hot atom reaction product internal energy distributions

    International Nuclear Information System (INIS)

    Quick, C.R. Jr.; Moore, D.S.

    1983-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is being utilized to investigate the rovibrational energy distributions produced by reactive and nonreactive collisions of translationally hot atoms with simple molecules. Translationally hot H atoms are produced by ArF laser photolysis of HBr. Using CARS we have monitored, in a state-specific and time-resolved manner, rotational excitation of HBr (v = 0), vibrational excitation of HBr and H 2 , rovibrational excitation of H 2 produced by the reaction H + HBr → H 2 + Br, and Br atom production by photolysis of HBr

  4. Tunable optical setup with high flexibility for spectrally resolved coherent anti-Stokes Raman scattering microscopy

    International Nuclear Information System (INIS)

    Bergner, G; Akimov, D; Bartelt, H; Dietzek, B; Popp, J; Schlücker, S

    2011-01-01

    A simplified setup for coherent anti-Stokes Raman scattering (CARS) microscopy is introduced, which allows for recording CARS images with 30 cm -1 excitation bandwidth for probing Raman bands between 500 and 900 cm -1 with minimal requirements for alignment. The experimental arrangement is based on electronic switching between CARS images recorded at different Raman resonances by combining a photonic crystal fiber (PCF) as broadband light source and an acousto-optical programmable dispersive filter (AOPDF) as tunable wavelength filter. Such spatial light modulator enables selection of a narrow-band spectrum to yield high vibrational contrast and hence chemical contrast in the resultant CARS images. Furthermore, an experimental approach to reconstruct spectral information from CARS image contrast is introduced

  5. Next generation hazard detection via ultrafast coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Brady, John J.; Pellegrino, Paul M.

    2013-05-01

    Multiplex coherent anti-Stokes Raman spectroscopy (MCARS) is used to detect an explosive precursor material and two chemical warfare simulants. The spectral bandwidth of the femtosecond laser pulse used in these studies is sufficient to coherently and simultaneously drive all the vibrational modes in the molecule of interest. The research performed here demonstrates that MCARS has the capability to detect an explosive precursor (e.g., acetone) and hazardous materials, such as dimethyl methylphosphonate and 2-chloroethyl methyl sulfide (a sarin and a mustard gas chemical warfare simulant, respectively), with high specificity. Evidence shows that MCARS is capable of overcoming common the sensitivity limitations of spontaneous Raman scattering, thus allowing for the detection of the target material in milliseconds with standard USB spectrometers as opposed to seconds with intensified spectrometers. The exponential increase in the number of scattered photons suggests that the MCARS technique may be capable of overcoming range detection challenges common to spontaneous Raman scattering.

  6. Stimulated-emission pumping enabling sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering microscopy

    NARCIS (Netherlands)

    Cleff, C.; Gross, P.; Fallnich, C.; Offerhaus, Herman L.; Herek, Jennifer Lynn; Kruse, K.; Beeker, W.P.; Lee, Christopher James; Boller, Klaus J.

    2013-01-01

    We present a theoretical investigation of stimulated emission pumping to achieve sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering (CARS) microscopy. A pair of control light fields is used to prepopulate the Raman state involved in the CARS process prior to the CARS

  7. Coherent anti-Stokes Raman scattering microscopy (CARS): Instrumentation and applications

    International Nuclear Information System (INIS)

    Djaker, Nadia; Lenne, Pierre-Francois; Marguet, Didier; Colonna, Anne; Hadjur, Christophe; Rigneault, Herve

    2007-01-01

    Recent advances in laser physics have permitted the development of a new kind of microscopy based on stimulated Raman scattering. This new technique known as Coherent anti-Stokes Raman scattering (CARS) microscopy allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capabilities. We review recent advances in CARS microscopy, with applications to chemical and biological systems. We also present an application of CARS microscopy with high optical resolution and spectral selectivity, in resolving structures in surface ex vivo stratum corneum by looking at the CH 2 stretching vibrational band. A strong CARS signal is backscattered from an intense forward generated CARS signal in thick samples. This makes noninvasive imaging of deep structures possible, without labeling or chemical treatments

  8. Quantitative assessment of spinal cord injury using circularly polarized coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Bae, Kideog; Zheng, Wei; Huang, Zhiwei

    2017-08-01

    We report the quantitative assessment of spinal cord injury using the circularly polarized coherent anti-Stokes Raman scattering (CP-CARS) technique together with Stokes parameters in the Poincaré sphere. The pump and Stokes excitation beams are circularly polarized to suppress both the linear polarization-dependent artifacts and the nonresonant background of tissue CARS imaging, enabling quantitative CP-CARS image analysis. This study shows that CP-CARS imaging uncovers significantly increased phase retardance of injured spinal cord tissue as compared to normal tissue, suggesting that CP-CARS is an appealing label-free imaging tool for determining the degree of tissue phase retardance, which could serve as a unique diagnostic parameter associated with nervous tissue injury.

  9. Broadband coherent anti-Stokes Raman spectroscopy with a modeless dye laser.

    Science.gov (United States)

    Hahn, J W; Park, C W; Park, S N

    1997-09-20

    We develop a modeless dye laser for broadband coherent anti-Stokes Raman spectroscopy (CARS) and investigate the operational characteristics of the modeless laser. The energy efficiency of the modeless laser is 6%, and the beam divergence is 0.65 mrad. We construct a compact movable CARS system with the modeless laser and a graphite tube furnace to assess the accuracy of the CARS temperature. It is found that the difference between the averaged CARS temperature and the radiation temperature measured with an optical pyrometer is <2% at a temperature range from 1000 to 2400 K. We also measure the averaged CARS temperature drift owing to the variation of the spectral distribution of the modeless laser, which is <1.5% during 5 h of operation.

  10. Femtosecond Coherent Anti-Stokes Raman Spectroscopy (CARS) As Next Generation Nonlinear LIDAR Spectroscopy and Microscopy

    International Nuclear Information System (INIS)

    Ooi, C. H. Raymond

    2009-01-01

    Nonlinear spectroscopy using coherent anti-Stokes Raman scattering and femtosecond laser pulses has been successfully developed as powerful tools for chemical analysis and biological imaging. Recent developments show promising possibilities of incorporating CARS into LIDAR system for remote detection of molecular species in airborne particles. The corresponding theory is being developed to describe nonlinear scattering of a mesoscopic particle composed of complex molecules by laser pulses with arbitrary shape and spectral content. Microscopic many-body transform theory is used to compute the third order susceptibility for CARS in molecules with known absorption spectrum and vibrational modes. The theory is combined with an integral scattering formula and Mie-Lorentz formulae, giving a rigorous formalism which provides powerful numerical experimentation of CARS spectra, particularly on the variations with the laser parameters and the direction of detection.

  11. Spatially dependent Rabi oscillations: An approach to sub-diffraction-limited coherent anti-Stokes Raman-scattering microscopy

    NARCIS (Netherlands)

    Beeker, Willem; Beeker, W.P.; Lee, Christopher James; Boller, Klaus J.; Gross, P.; Cleff, Carsten; Fallnich, Carsten; Offerhaus, Herman L.; Herek, Jennifer Lynn

    2010-01-01

    We present a theoretical investigation of coherent anti-Stokes Raman scattering (CARS) that is modulated by periodically depleting the ground-state population through Rabi oscillations driven by an additional control laser. We find that such a process generates optical sidebands in the CARS spectrum

  12. Visualizing Resonances in the Complex Plane with Vibrational Phase Contrast Coherent Anti-Stokes Raman Scattering (CARS)

    NARCIS (Netherlands)

    Jurna, M.; Garbacik, E.T.; Korterik, Jeroen P.; Herek, Jennifer Lynn; Otto, Cornelis; Offerhaus, Herman L.

    2010-01-01

    In coherent anti-Stokes Raman scattering (CARS), the emitted signal carries both amplitude and phase information of the molecules in the focal volume. Most CARS experiments ignore the phase component, but its detection allows for two advantages over intensity-only CARS. First, the pure resonant

  13. Coherent anti-Stokes Raman scattering microscopy: overcoming technical barriers for clinical translation.

    Science.gov (United States)

    Tu, Haohua; Boppart, Stephen A

    2014-01-01

    Clinical translation of coherent anti-Stokes Raman scattering microscopy is of great interest because of the advantages of noninvasive label-free imaging, high sensitivity, and chemical specificity. For this to happen, we have identified and review the technical barriers that must be overcome. Prior investigations have developed advanced techniques (features), each of which can be used to effectively overcome one particular technical barrier. However, the implementation of one or a small number of these advanced features in previous attempts for clinical translation has often introduced more tradeoffs than benefits. In this review, we outline a strategy that would integrate multiple advanced features to overcome all the technical barriers simultaneously, effectively reduce tradeoffs, and synergistically optimize CARS microscopy for clinical translation. The operation of the envisioned system incorporates coherent Raman micro-spectroscopy for identifying vibrational biomolecular markers of disease and single-frequency (or hyperspectral) Raman imaging of these specific biomarkers for real-time in vivo diagnostics and monitoring. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Dispersive Fourier transformation for megahertz detection of coherent stokes and anti-stokes Raman spectra

    Science.gov (United States)

    Bohlin, Alexis; Patterson, Brian D.; Kliewer, Christopher J.

    2017-11-01

    In many fields of study, from coherent Raman microscopy on living cells to time-resolved coherent Raman spectroscopy of gas-phase turbulence and combustion reaction dynamics, the need for the capability to time-resolve fast dynamical and nonrepetitive processes has led to the continued development of high-speed coherent Raman methods and new high-repetition rate laser sources, such as pulse-burst laser systems. However, much less emphasis has been placed on our ability to detect shot to shot coherent Raman spectra at equivalently high scan rates, across the kilohertz to megahertz regime. This is beyond the capability of modern scientific charge coupled device (CCD) cameras, for instance, as would be employed with a Czerny-Turner type spectrograph. As an alternative detection strategy with megahertz spectral detection rate, we demonstrate dispersive Fourier transformation detection of pulsed (∼90 ps) coherent Raman signals in the time-domain. Instead of reading the frequency domain signal out using a spectrometer and CCD, the signal is transformed into a time-domain waveform through dispersive Fourier transformation in a long single-mode fiber and read-out with a fast sampling photodiode and oscilloscope. Molecular O- and S-branch rotational sideband spectra from both N2 and H2 were acquired employing this scheme, and the waveform is fitted to show highly quantitative agreement with a molecular model. The total detection time for the rotational spectrum was 20 ns, indicating an upper limit to the detection frequency of ∼50 MHz, significantly faster than any other reported spectrally-resolved coherent anti-Stokes Raman detection strategy to date.

  15. Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

    Science.gov (United States)

    Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke

    2017-11-01

    High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

  16. Vibrational imaging and microspectroscopies based on coherent anti-Stokes Raman scattering microscopy

    International Nuclear Information System (INIS)

    Volkmer, Andreas

    2005-01-01

    For noninvasive characterization of chemical species or biological components within a complex heterogeneous system, their intrinsic molecular vibrational properties can be used in contrast mechanisms in optical microscopy. A series of recent advances have made coherent anti-Stokes Raman scattering (CARS) microscopy a powerful technique that allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capability. In this review, we discuss theoretical and experimental aspects of CARS microscopy in a collinear excitation beam geometry. Particular attention is given to the underlying physical principles behind the new features of CARS signal generation under tight focusing conditions. We provide a brief overview of the instrumentation of CARS microscopy and its experimental characterization by means of imaging of model systems and live unstained cells. CARS microscopy offers the possibility of spatially resolved vibrational spectroscopy, providing chemical and physical structure information of molecular specimens on the sub-micrometre length scale. We review multiplex CARS microspectroscopy allowing fast acquisition of frequency-resolved CARS spectra, time-resolved CARS microspectroscopy recording ultrafast Raman free induction decays and CARS correlation spectroscopy probing dynamical processes with chemical selectivity. (topical review)

  17. Surfactant uptake dynamics in mammalian cells elucidated with quantitative coherent anti-stokes Raman scattering microspectroscopy.

    Directory of Open Access Journals (Sweden)

    Masanari Okuno

    Full Text Available The mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL cells has been examined for a low surfactant concentration (0.01 w%. By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism.

  18. Insights into Caco-2 cell culture structure using coherent anti-Stokes Raman scattering (CARS) microscopy.

    Science.gov (United States)

    Saarinen, Jukka; Sözeri, Erkan; Fraser-Miller, Sara J; Peltonen, Leena; Santos, Hélder A; Isomäki, Antti; Strachan, Clare J

    2017-05-15

    We have used coherent anti-Stokes Raman scattering (CARS) microscopy as a novel and rapid, label-free and non-destructive imaging method to gain structural insights into live intestinal epithelial cell cultures used for drug permeability testing. Specifically we have imaged live Caco-2 cells in (bio)pharmaceutically relevant conditions grown on membrane inserts. Imaging conditions were optimized, including evaluation of suitable membrane materials and media solutions, as well as tolerable laser powers for non-destructive imaging of the live cells. Lipid structures, in particular lipid droplets, were imaged within the cells on the insert membranes. The size of the individual lipid droplets increased substantially over the 21-day culturing period up to approximately 10% of the volume of the cross section of individual cells. Variation in lipid content has important implications for intestinal drug permeation testing during drug development but has received limited attention to date due to a lack of suitable analytical techniques. CARS microscopy was shown to be well suited for such analysis with the potential for in situ imaging of the same individual cell-cultures that are used for permeation studies. Overall, the method may be used to provide important information about cell monolayer structure to better understand drug permeation results. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Femtosecond Coherent Anti-Stokes Raman Scattering Gas Phase Thermometry at 5 kHz

    Science.gov (United States)

    Fineman, Claresta; Lucht, Robert

    2014-05-01

    Understanding the thermal instabilities occurring in turbulent combustion, such as in modern gas turbine combustors, is critical for more reliable and fuel-efficient operation. Non-intrusive laser based spectroscopy methods have been documented as the techniques of choice for turbulent combustion diagnostics. Specifically, femtosecond coherent anti-Stokes Raman scattering (fs-CARS) thermometry has been established for temporal resolution of turbulent fluctuations in flame structure and provides accurate measurements across a wide range of temperatures. Experiments performed to date include 5 kHz pure vibrational N2 chirped probe-pulse fs-CARS thermometry on non-premixed hydrogen jet diffusion flames, methane jet diffusion flames, and the DLR gas turbine model combustor (GTMC). The fs-CARS signal generation process requires precise spatial and temporal overlap of tightly focused pulsed laser beams of less than 100 fs pulse duration. Here, signal loss due to beam steering, pressure fluctuations, or shear layer density gradients can become a problem. The effect of such interferences has been investigated using high velocity flow of compressed nitrogen gas from a converging-diverging nozzle. Resulting changes in fs-CARS spectra have been studied. Funding for this work was provided by the U.S. Department of Energy, Division of Chemical Sciences, Geosciences and Biosciences.

  20. Coherent anti-Stokes Raman spectroscopy temperature measurements in an internal combustion engine

    Science.gov (United States)

    Ball, Don; Driver, H. Steve T.; Hutcheon, Richard J.; Lockett, Russel J.; Robertson, Gerald N.

    1994-09-01

    Part of a project to investigate the physics and chemistry of alternative fuels in internal combustion engines is reported. Coherent anti-Stokes Raman spectroscopy (CARS) is used to probe the fuel-air mixture in the cylinder of a Richardo E6 variable compression ratio research engine. The laser system comprises a passively Q- switched single-longitudinal-mode frequency-doubled Nd:YAG laser and a broadband dye laser, both with a pulse length of 15 ns. A crankshaft encoder and electronic delay are used to fire the lasers at specified times during the engine cycle, and CARS spectra are acquired using a 0.75 m spectrometer and a 1024 optical multichannel analyzer. Because of the uncertainties associated with collisional narrowing in the theoretical modeling of high-pressure CARS spectra, temperatures are determined by comparing the engine spectra with a library of experimental CARS spectra from a calibrated high-pressure, high- temperature cell. This purely experimental technique is shown to be superior to two theoretical models under the considered conditions, giving temperatures during the compression stroke of the engine with standard deviations of typically 10 K and a possible systematic error of 15 K. Together with pressure records, this information is used as input data for chemical kinetic modeling of the combustion process.

  1. Nonequilibrium Supersonic Freestream Studied Using Coherent Anti-Stokes Raman Spectroscopy

    Science.gov (United States)

    Cutler, Andrew D.; Cantu, Luca M.; Gallo, Emanuela C. A.; Baurle, Rob; Danehy, Paul M.; Rockwell, Robert; Goyne, Christopher; McDaniel, Jim

    2015-01-01

    Measurements were conducted at the University of Virginia Supersonic Combustion Facility of the flow in a constant-area duct downstream of a Mach 2 nozzle. The airflow was heated to approximately 1200 K in the facility heater upstream of the nozzle. Dual-pump coherent anti-Stokes Raman spectroscopy was used to measure the rotational and vibrational temperatures of N2 and O2 at two planes in the duct. The expectation was that the vibrational temperature would be in equilibrium, because most scramjet facilities are vitiated air facilities and are in vibrational equilibrium. However, with a flow of clean air, the vibrational temperature of N2 along a streamline remains approximately constant between the measurement plane and the facility heater, the vibrational temperature of O2 in the duct is about 1000 K, and the rotational temperature is consistent with the isentropic flow. The measurements of N2 vibrational temperature enabled cross-stream nonuniformities in the temperature exiting the facility heater to be documented. The measurements are in agreement with computational fluid dynamics models employing separate lumped vibrational and translational/rotational temperatures. Measurements and computations are also reported for a few percent steam addition to the air. The effect of the steam is to bring the flow to thermal equilibrium, also in agreement with the computational fluid dynamics.

  2. Intracellular imaging of docosanol in living cells by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    You, Sixian; Liu, Yuan; Arp, Zane; Zhao, Youbo; Chaney, Eric J.; Marjanovic, Marina; Boppart, Stephen A.

    2017-07-01

    Docosanol is an over-the-counter topical agent that has proved to be one of the most effective therapies for treating herpes simplex labialis. However, the mechanism by which docosanol suppresses lesion formation remains poorly understood. To elucidate its mechanism of action, we investigated the uptake of docosanol in living cells using coherent anti-Stokes Raman scattering microscopy. Based on direct visualization of the deuterated docosanol, we observed highly concentrated docosanol inside living cells 24 h after drug treatment. In addition, different spatial patterns of drug accumulation were observed in different cell lines. In keratinocytes, which are the targeted cells of docosanol, the drug molecules appeared to be docking at the periphery of the cell membrane. In contrast, the drug molecules in fibroblasts appeared to accumulate in densely packed punctate regions throughout the cytoplasm. These results suggest that this molecular imaging approach is suitable for the longitudinal tracking of drug molecules in living cells to identify cell-specific trafficking and may also have implications for elucidating the mechanism by which docosanol suppresses lesion formation.

  3. Effect of scattering on coherent anti-Stokes Raman scattering (CARS) signals.

    Science.gov (United States)

    Ranasinghesagara, Janaka C; De Vito, Giuseppe; Piazza, Vincenzo; Potma, Eric O; Venugopalan, Vasan

    2017-04-17

    We develop a computational framework to examine the factors responsible for scattering-induced distortions of coherent anti-Stokes Raman scattering (CARS) signals in turbid samples. We apply the Huygens-Fresnel wave-based electric field superposition (HF-WEFS) method combined with the radiating dipole approximation to compute the effects of scattering-induced distortions of focal excitation fields on the far-field CARS signal. We analyze the effect of spherical scatterers, placed in the vicinity of the focal volume, on the CARS signal emitted by different objects (2μm diameter solid sphere, 2μm diameter myelin cylinder and 2μm diameter myelin tube). We find that distortions in the CARS signals arise not only from attenuation of the focal field but also from scattering-induced changes in the spatial phase that modifies the angular distribution of the CARS emission. Our simulations further show that CARS signal attenuation can be minimized by using a high numerical aperture condenser. Moreover, unlike the CARS intensity image, CARS images formed by taking the ratio of CARS signals obtained using x- and y-polarized input fields is relatively insensitive to the effects of spherical scatterers. Our computational framework provide a mechanistic approach to characterizing scattering-induced distortions in coherent imaging of turbid media and may inspire bottom-up approaches for adaptive optical methods for image correction.

  4. Coherent anti-Stokes Raman scattering imaging of lipids in cancer metastasis

    International Nuclear Information System (INIS)

    Le, Thuc T; Huff, Terry B; Cheng, Ji-Xin

    2009-01-01

    Lipid-rich tumours have been associated with increased cancer metastasis and aggressive clinical behaviours. Nonetheless, pathologists cannot classify lipid-rich tumours as a clinically distinctive form of carcinoma due to a lack of mechanistic understanding on the roles of lipids in cancer development. Coherent anti-Stokes Raman scattering (CARS) microscopy is employed to study cancer cell behaviours in excess lipid environments in vivo and in vitro. The impacts of a high fat diet on cancer development are evaluated in a Balb/c mice cancer model. Intravital flow cytometry and histology are employed to enumerate cancer cell escape to the bloodstream and metastasis to lung tissues, respectively. Cancer cell motility and tissue invasion capability are also evaluated in excess lipid environments. CARS imaging reveals intracellular lipid accumulation is induced by excess free fatty acids (FFAs). Excess FFAs incorporation onto cancer cell membrane induces membrane phase separation, reduces cell-cell contact, increases surface adhesion, and promotes tissue invasion. Increased plasma FFAs level and visceral adiposity are associated with early rise in circulating tumour cells and increased lung metastasis. Furthermore, CARS imaging reveals FFAs-induced lipid accumulation in primary, circulating, and metastasized cancer cells. Lipid-rich tumours are linked to cancer metastasis through FFAs-induced physical perturbations on cancer cell membrane. Most importantly, the revelation of lipid-rich circulating tumour cells suggests possible development of CARS intravital flow cytometry for label-free detection of early-stage cancer metastasis

  5. Macrophages interaction with pulmonary surfactant using coherent anti-Stokes Raman scattering (CARS) microscopy

    Science.gov (United States)

    Ocampo, Minette; Telesford, Dana Marie; Allen, Heather

    2012-04-01

    Alveolar pulmonary surfactant, composed mostly of phospholipids, is essential for maintenance of normal lung function. However, increased production of lung surfactant can lead to many pulmonary inflammatory disorders. Alveolar macrophages are responsible for the degradation of the surfactant and exhibit increased lipid uptake in inflamated lungs. Owing to their limited clearance capability, excessive accumulation of surfactant may impair their phagocytic function. In this study, the interaction of the macrophages with different lipid components was studied using coherent anti-Stokes Raman scattering (CARS) microscopy. CARS microscopy, a nonlinear vibrational technique which combines spectroscopy and microscopy, allows noninvasive characterization and imaging of chemical species without preparation or labeling. A monolayer of THP-1 macrophages and palmitic acid-d31 on phosphate buffer solution was transferred to a coverslip using the Langmuir-Blodgett method and then imaged using CARS by mapping the CH2 stretch signal of the lipid membrane of the macrophage and C-D stretch signal from palmitic acid-d31. Preliminary results showed CARS images of the macrophage on the solid substrate and thermal degradation of the sample due to long exposure to high laser power. A contrast image is expected to be observed by mapping the CH2 and C-D signals, which can show the lipid interaction and phagocytosis of the macrophage.

  6. Investigation of lipid homeostasis in living Drosophila by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

    2012-12-01

    To improve our understanding of lipid metabolism, Drosophila is used as a model animal, and its lipid homeostasis is monitored by coherent anti-Stokes Raman scattering microscopy. We are able to achieve in vivo imaging of larval fat body (analogous to adipose tissue in mammals) and oenocytes (analogous to hepatocytes) in Drosophila larvae at subcellular level without any labeling. By overexpressing two lipid regulatory proteins-Brummer lipase (Bmm) and lipid storage droplet-2 (Lsd-2)-we found different phenotypes and responses under fed and starved conditions. Comparing with the control larva, we observed more lipid droplet accumulation by ˜twofold in oenocytes of fat-body-Bmm-overexpressing (FB-Bmm-overexpressing) mutant under fed condition, and less lipid by ˜fourfold in oenocytes of fat-body-Lsd-2-overexpressing (FB-Lsd-2-overexpressing) mutant under starved condition. Moreover, together with reduced size of lipid droplets, the lipid content in the fat body of FB-Bmm-overexpressing mutant decreases much faster than that of the control and FB-Lsd-2-overexpressing mutant during starvation. From long-term starvation assay, we found FB-Bmm-overexpressing mutant has a shorter lifespan, which can be attributed to faster consumption of lipid in its fat body. Our results demonstrate in vivo observations of direct influences of Bmm and Lsd-2 on lipid homeostasis in Drosophila larvae.

  7. Temperature Measurements in Reacting Flows Using Time-Resolved Femtosecond Coherent Anti-Stokes Raman Scattering (fs-CARS) Spectroscopy (Postprint)

    National Research Council Canada - National Science Library

    Roy, Sukesh; Kinnius, Paul J; Lucht, Robert P; Gord, James R

    2007-01-01

    Time-resolved femtosecond coherent anti-Stokes Raman scattering (fs-CARS) spectroscopy of the nitrogen molecule is used for the measurement of temperature in atmospheric-pressure, near-adiabatic, hydrogen-air diffusion flames...

  8. Pure-rotational H2thermometry by ultrabroadband coherent anti-Stokes Raman spectroscopy.

    Science.gov (United States)

    Courtney, Trevor L; Bohlin, Alexis; Patterson, Brian D; Kliewer, Christopher J

    2017-06-14

    Coherent anti-Stokes Raman spectroscopy (CARS) is a sensitive technique for probing highly luminous flames in combustion applications to determine temperatures and species concentrations. CARS thermometry has been demonstrated for the vibrational Q-branch and pure-rotational S-branch of several small molecules. Practical advantages of pure-rotational CARS, such as multi-species detection, reduction of coherent line mixing and collisional narrowing even at high pressures, and the potential for more precise thermometry, have motivated experimental and theoretical advances in S-branch CARS of nitrogen (N 2 ), for example, which is a dominant species in air-fed combustion processes. Although hydrogen (H 2 ) is of interest given its prevalence as a reactant and product in many gas-phase reactions, laser bandwidth limitations have precluded the extension of CARS thermometry to the H 2 S-branch. We demonstrate H 2 thermometry using hybrid femtosecond/picosecond pure-rotational CARS, in which a broadband pump/Stokes pulse enables simultaneous excitation of the set of H 2 S-branch transitions populated at flame temperatures over the spectral region of 0-2200 cm -1 . We present a pure-rotational H 2 CARS spectral model for data fitting and compare extracted temperatures to those from simultaneously collected N 2 spectra in two systems of study: a heated flow and a diffusion flame on a Wolfhard-Parker slot burner. From 300 to 650 K in the heated flow, the H 2 and N 2 CARS extracted temperatures are, on average, within 2% of the set temperature. For flame measurements, the fitted H 2 and N 2 temperatures are, on average, within 5% of each other from 300 to 1600 K. Our results confirm the viability of pure-rotational H 2 CARS thermometry for probing combustion reactions.

  9. Multiplex coherent anti-Stokes Raman scattering microspectroscopy of brain tissue with higher ranking data classification for biomedical imaging

    Science.gov (United States)

    Pohling, Christoph; Bocklitz, Thomas; Duarte, Alex S.; Emmanuello, Cinzia; Ishikawa, Mariana S.; Dietzeck, Benjamin; Buckup, Tiago; Uckermann, Ortrud; Schackert, Gabriele; Kirsch, Matthias; Schmitt, Michael; Popp, Jürgen; Motzkus, Marcus

    2017-06-01

    Multiplex coherent anti-Stokes Raman scattering (MCARS) microscopy was carried out to map a solid tumor in mouse brain tissue. The border between normal and tumor tissue was visualized using support vector machines (SVM) as a higher ranking type of data classification. Training data were collected separately in both tissue types, and the image contrast is based on class affiliation of the single spectra. Color coding in the image generated by SVM is then related to pathological information instead of single spectral intensities or spectral differences within the data set. The results show good agreement with the H&E stained reference and spontaneous Raman microscopy, proving the validity of the MCARS approach in combination with SVM.

  10. A high-resolution two-pulse coherent anti-Stokes Raman scattering spectrum using a spectral amplitude modulation

    International Nuclear Information System (INIS)

    Lu, Chenhui; Zhang, Shian; Wu, Meizhen; Jia, Tianqing; Sun, Zhenrong; Qiu, Jianrong

    2013-01-01

    Femtosecond coherent anti-Stokes Raman scattering (CARS) spectra suffer from low spectral resolution because of the broadband laser spectrum. In this paper, we propose a feasible scheme to achieve a high-resolution two-pulse CARS spectrum by shaping both the pump and probe pulses using rectangular amplitude modulation. We show that a narrowband hole in the CARS spectrum can be created by the amplitude-shaped laser pulse, the position of which is correlated with the Raman resonant frequency of the molecule. Thus, by observing holes in the CARS spectrum, we are able to obtain a high-resolution CARS spectrum and the energy-level diagram of the molecule. (paper)

  11. Two-beam ultrabroadband coherent anti-Stokes Raman spectroscopy for high resolution gas-phase multiplex imaging

    International Nuclear Information System (INIS)

    Bohlin, Alexis; Kliewer, Christopher J.

    2014-01-01

    We propose and develop a method for wideband coherent anti-Stokes Raman spectroscopy (CARS) in the gas phase and demonstrate the single-shot measurement of N 2 , H 2 , CO 2 , O 2 , and CH 4 . Pure-rotational and vibrational O-, Q-, and S- branch spectra are collected simultaneously, with high spectral and spatial resolution, and within a single-laser-shot. The relative intensity of the rotational and vibrational signals can be tuned arbitrarily using polarization techniques. The ultrashort 7 fs pump and Stokes pulses are automatically overlapped temporally and spatially using a two-beam CARS technique, and the crossed probe beam allows for excellent spatial sectioning of the probed location

  12. Evans blue dye-enhanced imaging of the brain microvessels using spectral focusing coherent anti-Stokes Raman scattering microscopy.

    Directory of Open Access Journals (Sweden)

    Bo-Ram Lee

    Full Text Available We performed dye-enhanced imaging of mouse brain microvessels using spectral focusing coherent anti-Stokes Raman scattering (SF-CARS microscopy. The resonant signals from C-H stretching in forward CARS usually show high background intensity in tissues, which makes CARS imaging of microvessels difficult. In this study, epi-detection of back-scattered SF-CARS signals showed a negligible background, but the overall intensity of resonant CARS signals was too low to observe the network of brain microvessels. Therefore, Evans blue (EB dye was used as contrasting agent to enhance the back-scattered SF-CARS signals. Breakdown of brain microvessels by inducing hemorrhage in a mouse was clearly visualized using backward SF-CARS signals, following intravenous injection of EB. The improved visualization of brain microvessels with EB enhanced the sensitivity of SF-CARS, detecting not only the blood vessels themselves but their integrity as well in the brain vasculature.

  13. Combining deep learning and coherent anti-Stokes Raman scattering imaging for automated differential diagnosis of lung cancer

    Science.gov (United States)

    Weng, Sheng; Xu, Xiaoyun; Li, Jiasong; Wong, Stephen T. C.

    2017-10-01

    Lung cancer is the most prevalent type of cancer and the leading cause of cancer-related deaths worldwide. Coherent anti-Stokes Raman scattering (CARS) is capable of providing cellular-level images and resolving pathologically related features on human lung tissues. However, conventional means of analyzing CARS images requires extensive image processing, feature engineering, and human intervention. This study demonstrates the feasibility of applying a deep learning algorithm to automatically differentiate normal and cancerous lung tissue images acquired by CARS. We leverage the features learned by pretrained deep neural networks and retrain the model using CARS images as the input. We achieve 89.2% accuracy in classifying normal, small-cell carcinoma, adenocarcinoma, and squamous cell carcinoma lung images. This computational method is a step toward on-the-spot diagnosis of lung cancer and can be further strengthened by the efforts aimed at miniaturizing the CARS technique for fiber-based microendoscopic imaging.

  14. Effects of collisions on electronic-resonance-enhanced coherent anti-Stokes Raman scattering of nitric oxide

    Science.gov (United States)

    Patnaik, Anil K.; Roy, Sukesh; Gord, James R.; Lucht, Robert P.; Settersten, Thomas B.

    2009-06-01

    A six-level model is developed and used to study the effects of collisional energy transfer and dephasing on electronic-resonance-enhanced coherent anti-Stokes Raman scattering (ERE-CARS) in nitric oxide. The model includes the three levels that are coherently coupled by the three applied lasers as well as three additional bath levels that enable inclusion of the effects of electronic quenching and rotational energy transfer. The density-matrix equations that describe the evolution of the relevant populations and coherences are presented. The parametric dependencies of the ERE-CARS signal on collisional energy transfer and dephasing processes are described in terms of both a steady-state analytical solution and the numerical solutions to the governing equations. In the weak-field limit, the ERE-CARS signal scales inversely with the square of the dephasing rates for the electronic and Raman coherences. In accord with published experimental observations [Roy et al., Appl. Phys. Lett. 89, 104105 (2006)], the ERE-CARS signal is shown to be insensitive to the collisional quenching rate. Parametric dependencies on quenching, rotational energy transfer, and pure electronic dephasing are presented, demonstrating reduced collisional dependence for saturating laser fields.

  15. Effects of moderate pump and Stokes chirp on chirped-probe pulse femtosecond coherent anti-Stokes Raman scattering thermometry

    KAUST Repository

    Gu, Mingming

    2018-01-08

    The effects of moderate levels of chirp in the pump and Stokes pulses on chirped-probe-pulse femtosecond coherent anti-Stokes Raman scattering (CPP fs CARS) were investigated. The frequency chirp in the pump and Stokes pulses was introduced by placing SF11 glass disks with thicknesses of 10 mm or 20 mm in the optical path for these beams. The magnitude of the chirp in the probe beam was much greater and was induced by placing a 30-cm rod of SF10 glass in the beam path. The temperature measurements were performed in hydrogen/air non-premixed flames stabilized on a Hencken burner at equivalence ratios of 0.3, 0.5, 0.7, and 1.0. We performed measurements with no disks in pump and Stokes beam paths, and then with disks of 10 mm and 20 mm placed in both beam paths. The spectrum of the nonresonant background four-wave mixing signal narrowed considerably with increasing pump and Stokes chirp, while the resonant CARS signal was relatively unaffected. Consequently, the interference of the nonresonant background with the resonant CARS signal in the frequency-spread dephasing region of the spectrum was minimized. The increased rate of decay of the resonant CARS signal with increasing temperature was thus readily apparent. We have started to analyze the CPP fs CARS thermometry data and initial results indicate improved accuracy and precision are obtained due to moderate chirp in the pump and Stokes laser pulses.

  16. Quantitative chemical imaging with background-free multiplex coherent anti-Stokes Raman scattering by dual-soliton Stokes pulses

    Science.gov (United States)

    Chen, Kun; Wu, Tao; Wei, Haoyun; Zhou, Tian; Li, Yan

    2016-01-01

    Coherent anti-Stokes Raman microscopy (CARS) is a quantitative, chemically specific, and label-free optical imaging technique for studying inhomogeneous systems. However, the complicating influence of the nonresonant response on the CARS signal severely limits its sensitivity and specificity and especially limits the extent to which CARS microscopy has been used as a fully quantitative imaging technique. On the basis of spectral focusing mechanism, we establish a dual-soliton Stokes based CARS microspectroscopy and microscopy scheme capable of quantifying the spatial information of densities and chemical composition within inhomogeneous samples, using a single fiber laser. Dual-soliton Stokes scheme not only removes the nonresonant background but also allows robust acquisition of multiple characteristic vibrational frequencies. This all-fiber based laser source can cover the entire fingerprint (800-2200 cm−1) region with a spectral resolution of 15 cm−1. We demonstrate that quantitative degree determination of lipid-chain unsaturation in the fatty acids mixture can be achieved by the characterization of C = C stretching and CH2 deformation vibrations. For microscopy purposes, we show that the spatially inhomogeneous distribution of lipid droplets can be further quantitatively visualized using this quantified degree of lipid unsaturation in the acyl chain for contrast in the hyperspectral CARS images. The combination of compact excitation source and background-free capability to facilitate extraction of quantitative composition information with multiplex spectral peaks will enable wider applications of quantitative chemical imaging in studying biological and material systems. PMID:27867704

  17. Detection of Lipid-Rich Prostate Circulating Tumour Cells with Coherent Anti-Stokes Raman Scattering Microscopy

    International Nuclear Information System (INIS)

    Mitra, Ranjana; Chao, Olivia; Urasaki, Yasuyo; Goodman, Oscar B; Le, Thuc T

    2012-01-01

    Circulating tumour cells (CTC) are an important indicator of metastasis and associated with a poor prognosis. Detection sensitivity and specificity of CTC in the peripheral blood of metastatic cancer patient remain a technical challenge. Coherent anti-Stokes Raman scattering (CARS) microscopy was employed to examine the lipid content of CTC isolated from the peripheral blood of metastatic prostate cancer patients. CARS microscopy was also employed to evaluate lipid uptake and mobilization kinetics of a metastatic human prostate cancer cell line. One hundred CTC from eight metastatic prostate cancer patients exhibited strong CARS signal which arose from intracellular lipid. In contrast, leukocytes exhibited weak CARS signal which arose mostly from cellular membrane. On average, CARS signal intensity of prostate CTC was 7-fold higher than that of leukocytes (P<0.0000001). When incubated with human plasma, C4-2 metastatic human prostate cancer cells exhibited rapid lipid uptake kinetics and slow lipid mobilization kinetics. Higher expression of lipid transport proteins in C4-2 cells compared to non-transformed RWPE-1 and non-malignant BPH-1 prostate epithelial cells further indicated strong affinity for lipid of metastatic prostate cancer cells. Intracellular lipid could serve as a biomarker for prostate CTC which could be sensitively detected with CARS microscopy in a label-free manner. Strong affinity for lipid by metastatic prostate cancer cells could be used to improve detection sensitivity and therapeutic targeting of prostate CTC

  18. Paranodal myelin retraction in relapsing experimental autoimmune encephalomyelitis visualized by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Fu, Yan; Frederick, Terra J.; Huff, Terry B.; Goings, Gwendolyn E.; Miller, Stephen D.; Cheng, Ji-Xin

    2011-10-01

    How demyelination is initiated is a standing question for pathology of multiple sclerosis. By label-free coherent anti-Stokes Raman scattering (CARS) imaging of myelin lipids, we investigate myelin integrity in the lumbar spinal cord tissue isolated from naïve SJL mice, and from mice at the onset, peak acute, and remission stages of relapsing experimental autoimmune encephalomyelitis (EAE). Progressive demyelinating disease is initially characterized by the retraction of paranodal myelin both at the onset of disease and at the borders of acute demyelinating lesions. Myelin retraction is confirmed by elongated distribution of neurofascin proteins visualized by immunofluorescence. The disruption of paranodal myelin subsequently exposes Kv1.2 channels at the juxtaparanodes and lead to the displacement of Kv1.2 channels to the paranodal and nodal domains. Paranodal myelin is partially restored during disease remission, indicating spontaneous myelin regeneration. These findings suggest that paranodal domain injury precedes formation of internodal demyelinating lesions in relapsing EAE. Our results also demonstrate that CARS microscopy is an effective readout of myelin disease burden.

  19. Effects of phase and coupling between the vibrational modes on selective excitation in coherent anti-Stokes Raman scattering microscopy

    International Nuclear Information System (INIS)

    Patel, Vishesha; Malinovsky, Vladimir S.; Malinovskaya, Svetlana

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy has been a major tool of investigation of biological structures as it contains the vibrational signature of molecules. A quantum control method based on chirped pulse adiabatic passage was recently proposed for selective excitation of a predetermined vibrational mode in CARS microscopy [Malinovskaya and Malinovsky, Opt. Lett. 32, 707 (2007)]. The method utilizes the chirp sign variation at the peak pulse amplitude and gives a robust adiabatic excitation of the desired vibrational mode. Using this method, we investigate the impact of coupling between vibrational modes in molecules on controllability of excitation of the CARS signal. We analyze two models of two coupled two-level systems (TLSs) having slightly different transitional frequencies. The first model, featuring degenerate ground states of the TLSs, gives robust adiabatic excitation and maximum coherence in the resonant TLS for positive value of the chirp. In the second model, implying nondegenerate ground states in the TLSs, a population distribution is observed in both TLSs, resulting in a lack of selectivity of excitation and low coherence. It is shown that the relative phase and coupling between the TLSs play an important role in optimizing coherence in the desired vibrational mode and suppressing unwanted transitions in CARS microscopy.

  20. Exploring the interactions between peptides and lipid bilayers using coherent anti-Stokes Raman scattering and two-photon fluorescence

    Science.gov (United States)

    Mari, M.; Mouras, R.; Downes, A.; Elfick, A.

    2011-06-01

    We have used a versatile and powerful microscope[1] for multi-modal biomedical imaging on which we combine Coherent Anti-Stokes Raman Scattering (CARS) with Two Photon Excitation Fluorescence (TPEF) using a Nd: YVO4 pump laser. We acquired 2PEF, CARS, and phase contrast images of Multilamellar Vesicles (MLVs) and Giant Unilamellar Vesicles (GUVs), as well as Raman spectra of the constituent lipids. A wide range of peptides are harmful to cells by altering the structure of the biological membranes. This effect depends on the composition of the membrane and the chemical structure of the peptide. The peptide we studied is the beta amyloid Aβ which is a major component of the amyloid plaques deposited on neuronal membranes of Alzheimer's disease (AD) patients. AD is neurodegenerative disorder in which the hallmark symptoms include cognitive decline and dementia[2] and is characterized by the formation of extracellular amyloid fibrils on the neuronal membranes of the brain. Many questions still remain unanswered concerning the destabilization of cellular ionic homeostasis due to pores formed during the interactions of lipid membranes with peptides. In this project, biomimics of cell membranes are used. The structures that best mimic the plasma membranes are MLVs or GUVs. These vesicles are formed using the gentle hydration technique[3] or the electroformation technique[4] respectively and are composed of phospholipids such as DOPC, DPPC, D62PPC and their binary mixtures. The MLVs and GUVs imaging by CARS and TPEF microscopy not only permits the direct imaging of the leakage phenomenon caused by the toxic peptide (Aβ) on the lipid bilayer, but also records simultaneously the lateral structure of the bilayer and peptide distribution in the plane across the membrane.

  1. Raman and coherent anti-Stokes Raman scattering microscopy studies of changes in lipid content and composition in hormone-treated breast and prostate cancer cells

    Science.gov (United States)

    Potcoava, Mariana C.; Futia, Gregory L.; Aughenbaugh, Jessica; Schlaepfer, Isabel R.; Gibson, Emily A.

    2014-11-01

    Increasing interest in the role of lipids in cancer cell proliferation and resistance to drug therapies has motivated the need to develop better tools for cellular lipid analysis. Quantification of lipids in cells is typically done by destructive chromatography protocols that do not provide spatial information on lipid distribution and prevent dynamic live cell studies. Methods that allow the analysis of lipid content in live cells are therefore of great importance. Using micro-Raman spectroscopy and coherent anti-Stokes Raman scattering (CARS) microscopy, we generated a lipid profile for breast (T47D, MDA-MB-231) and prostate (LNCaP, PC3) cancer cells upon exposure to medroxyprogesterone acetate (MPA) and synthetic androgen R1881. Combining Raman spectra with CARS imaging, we can study the process of hormone-mediated lipogenesis. Our results show that hormone-treated cancer cells T47D and LNCaP have an increased number and size of intracellular lipid droplets and higher degree of saturation than untreated cells. MDA-MB-231 and PC3 cancer cells showed no significant changes upon treatment. Principal component analysis with linear discriminant analysis of the Raman spectra was able to differentiate between cancer cells that were treated with MPA, R1881, and untreated.

  2. In planta imaging of Δ9-tetrahydrocannabinolic acid in Cannabis sativa L. with hyperspectral coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Garbacik, Erik T.; Korai, Roza P.; Frater, Eric H.; Korterik, Jeroen P.; Otto, Cees; Offerhaus, Herman L.

    2013-04-01

    Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ9-tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question.

  3. Investigation of protein distribution in solid lipid particles and its impact on protein release using coherent anti-Stokes Raman scattering microscopy

    DEFF Research Database (Denmark)

    Christophersen, Philip C.; Birch, Ditlev; Saarinen, Jukka

    2015-01-01

    The aim of this study was to gain new insights into protein distribution in solid lipid microparticles (SLMs) and subsequent release mechanisms using a novel label-free chemical imaging method, coherent anti-Stokes Raman scattering (CARS) microscopy. Lysozyme-loaded SLMs were prepared using...... in the solid lipid matrix, which required full lipolysis of the entire matrix to release lysozyme completely. Therefore, SLMs with lysozyme incorporated in an aqueous solution released lysozyme much faster than with lysozyme incorporated as a solid. In conclusion, CARS microscopy was an efficient and non......-destructive method for elucidating the distribution of lysozyme in SLMs. The interpretation of protein distribution and release during lipolysis enabled elucidation of protein release mechanisms. In future, CARS microscopy analysis could facilitate development of a wide range of protein-lipid matrices with tailor...

  4. Coherent Anti-Stokes and Coherent Stokes in Raman Scattering by Superconducting Nanowire Single-Photon Detector for Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Annepu Venkata Naga Vamsi

    2016-01-01

    Full Text Available We have reported the measurement of temperature by using coherent anti-Stroke and coherent Stroke Raman scattering using superconducting nano wire single-photon detector. The measured temperatures by both methods (Coherent Anti-Raman scattering & Coherent Stroke Raman scattering and TC 340 are in good accuracy of ± 5 K temperature range. The length of the pipe line under test can be increased by increasing the power of the pump laser. This methodology can be widely used to measure temperatures at instantaneous positions in test pipe line or the entire temperature of the pipe line under test.

  5. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Kai [School of Science, Tianjin University of Technology and Education, Tianjin, 300222 (China); Lee, Soo-Y., E-mail: sooying@ntu.edu.sg [Division of Physics & Applied Physics, and Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-12-15

    Coherent anti-Stokes Raman spectroscopy (CARS) is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  6. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Science.gov (United States)

    Niu, Kai; Lee, Soo-Y.

    2015-12-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  7. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    International Nuclear Information System (INIS)

    Niu, Kai; Lee, Soo-Y.

    2015-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms

  8. Label-free assessment of adipose-derived stem cell differentiation using coherent anti-Stokes Raman scattering and multiphoton microscopy

    Science.gov (United States)

    Mouras, Rabah; Bagnaninchi, Pierre O.; Downes, Andrew R.; Elfick, Alistair P. D.

    2012-11-01

    Adult stem cells (SCs) hold great potential as likely candidates for disease therapy but also as sources of differentiated human cells in vitro models of disease. In both cases, the label-free assessment of SC differentiation state is highly desirable, either as a quality-control technology ensuring cells to be used clinically are of the desired lineage or to facilitate in vitro time-course studies of cell differentiation. We investigate the potential of nonlinear optical microscopy as a minimally invasive technology to monitor the differentiation of adipose-derived stem cells (ADSCs) into adipocytes and osteoblasts. The induction of ADSCs toward these two different cell lineages was monitored simultaneously using coherent anti-Stokes Raman scattering, two photon excitation fluorescence (TPEF), and second harmonic generation at different time points. Changes in the cell's morphology, together with the appearance of biochemical markers of cell maturity were observed, such as lipid droplet accumulation for adipo-induced cells and the formation of extra-cellular matrix for osteo-induced cells. In addition, TPEF of flavoproteins was identified as a proxy for changes in cell metabolism that occurred throughout ADSC differentiation toward both osteoblasts and adipocytes. These results indicate that multimodal microscopy has significant potential as an enabling technology for the label-free investigation of SC differentiation.

  9. Label-free imaging of Drosophila in vivo by coherent anti-Stokes Raman scattering and two-photon excitation autofluorescence microscopy

    Science.gov (United States)

    Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

    2011-01-01

    Drosophila is one of the most valuable model organisms for studying genetics and developmental biology. The fat body in Drosophila, which is analogous to the liver and adipose tissue in human, stores lipids that act as an energy source during its development. At the early stages of metamorphosis, the fat body remodeling occurs involving the dissociation of the fat body into individual fat cells. Here we introduce a combination of coherent anti-Stokes Raman scattering (CARS) and two-photon excitation autofluorescence (TPE-F) microscopy to achieve label-free imaging of Drosophila in vivo at larval and pupal stages. The strong CARS signal from lipids allows direct imaging of the larval fat body and pupal fat cells. In addition, the use of TPE-F microscopy allows the observation of other internal organs in the larva and autofluorescent globules in fat cells. During the dissociation of the fat body, the findings of the degradation of lipid droplets and an increase in autofluorescent globules indicate the consumption of lipids and the recruitment of proteins in fat cells. Through in vivo imaging and direct monitoring, CARS microscopy may help elucidate how metamorphosis is regulated and study the lipid metabolism in Drosophila.

  10. Dual-pump coherent anti-Stokes Raman scattering system for temperature and species measurements in an optically accessible high-pressure gas turbine combustor facility

    Science.gov (United States)

    Thariyan, Mathew P.; Bhuiyan, Aizaz H.; Meyer, Scott E.; Naik, Sameer V.; Gore, Jay P.; Lucht, Robert P.

    2011-01-01

    The development and implementation of a dual-pump coherent anti-Stokes Raman scattering (DP-CARS) system employing two optical sub-systems to measure temperature and major species concentrations at multiple locations in the flame zone of a high-pressure, liquid-fueled gas turbine combustor are discussed. An optically accessible gas turbine combustor facility (GTCF) was utilized to perform these experiments. A window assembly has been designed, fabricated, and assembled in the GTCF to allow optical access from three directions using a pair of thin and thick fused silica windows on each side. A lean direct injection (LDI) device consisting of an array of nine integrated air swirlers and fuel injectors was operated using Jet-A fuel at inlet air temperatures up to 725 K and combustor pressures up to 1.03 MPa. The DP-CARS system was used to measure temperature and CO2/N2 concentration ratio on single laser shots. An injection-seeded optical parametric oscillator (OPO) was used as a narrowband pump laser source in order to potentially reduce shot-to-shot fluctuations in the CARS data. Large prisms mounted on computer-controlled translation stages were used to direct the CARS beams either into the main leg optical system for measurements in the GTCF or to a reference leg optical system for measurements of the non-resonant spectrum and for alignment of the CARS system. The spatial maps of temperature and major species concentrations were obtained in high-pressure LDI flames by translating the CARS probe volume in the axial and vertical directions inside the combustor rig without loss of optical alignment.

  11. Coherent anti-Stokes Raman scattering for quantitative temperature and concentration measurements in a high-pressure gas turbine combustor rig

    Science.gov (United States)

    Thariyan, Mathew Paul

    Dual-pump coherent anti-Stokes Raman scattering (DP-CARS) temperature and major species (CO2/N2) concentration measurements have been performed in an optically-accessible high-pressure gas turbine combustor facility (GTCF) and for partially-premixed and non-premixed flames in a laminar counter-flow burner. A window assembly incorporating pairs of thin and thick fused silica windows on three sides was designed, fabricated, and assembled in the GTCF for advanced laser diagnostic studies. An injection-seeded optical parametric oscillator (OPO) was used as a narrowband pump laser source in the dual-pump CARS system. Large prisms on computer-controlled translation stages were used to direct the CARS beams either into the main optics leg for measurements in the GTCF or to a reference optics leg for measurements of the nonresonant CARS spectrum and for aligning the CARS system. Combusting flows were stabilized with liquid fuel injection only for the central injector of a 9-element lean direct injection (LDI) device developed at NASA Glenn Research Center. The combustor was operated using Jet A fuel at inlet air temperatures up to 725 K and combustor pressures up to 1.03 MPa. Single-shot DP-CARS spectra were analyzed using the Sandia CARSFT code in the batch operation mode to yield instantaneous temperature and CO2/N2 concentration ratio values. Spatial maps of mean and standard deviations of temperature and CO2/N2 concentrations were obtained in the high-pressure LDI flames by translating the CARS probe volume in axial and vertical directions inside the combustor rig. The mean temperature fields demonstrate the effect of the combustor conditions on the overall flame length and the average flame structure. The temperature relative standard deviation values indicate thermal fluctuations due to the presence of recirculation zones and/or flame brush fluctuations. The correlation between the temperature and relative CO 2 concentration data has been studied at various combustor

  12. CARS (Coherent Anti-stokes Raman Spectroscopy) diagnostics of high pressure combustion. Final technical report 15 Feb 1979-30 Sep 1982

    Energy Technology Data Exchange (ETDEWEB)

    Stufflebeam, J.H.; Shirley, J.A.; Hall, R.J.

    1982-11-01

    Under Contract DAAG29-79-C-0008 sponsored by the Army Research Office, the United Technologies Research Center (UTRC) has conducted basic research investigations into coherent anti-Stokes Human spectroscopy (CARS). CARS is a remote laser diagnostic technique for temperature and species measurements in hostile combustion environments. As such it possesses considerable relevance to the Army in the general areas of ballistics, propulsion and internal combustion engines. This final report describes the results of the investigation which were conducted in two specific areas. The first area concerns the effects of high pressure, specifically the phenomenon of collisional narrowing, on CARS spectra from which temperature and density information device. Experimental studies of CARS spectra are conducted in N2 and CO2 in a heated, high pressure cell. The experimental spectra were in excellent agreement with the theoretical model developed to describe high pressure CARS spectroscopy.

  13. Raman Spectroscopic Studies of Methane Gas Hydrates

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.

    2009-01-01

    A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory.......A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory....

  14. Observation of anomalous Stokes versus anti-Stokes ratio in MoTe2 atomic layers

    Science.gov (United States)

    Goldstein, Thomas; Chen, Shao-Yu; Xiao, Di; Ramasubramaniam, Ashwin; Yan, Jun

    We grow hexagonal molybdenum ditelluride (MoTe2), a prototypical transition metal dichalcogenide (TMDC) semiconductor, with chemical vapor transport methods and investigate its atomic layers with Stokes and anti-Stokes Raman scattering. We report observation of all six types of zone center optical phonons. Quite remarkably, the anti-Stokes Raman intensity of the low energy layer-breathing mode becomes more intense than the Stokes peak under certain experimental conditions, creating an illusion of 'negative temperature'. This effect is tunable, and can be switched from anti-Stokes enhancement to suppression by varying the excitation wavelength. We interpret this observation to be a result of resonance effects arising from the C excitons in the vicinity of the Brillouin zone center, which are robust even for multiple layers of MoTe2. The intense anti-Stokes Raman scattering provides a cooling channel for the crystal and opens up opportunities for laser cooling of atomically thin TMDC semiconductor devices. Supported by the University of Massachusetts Amherst, the National Science Foundation Center for Hierarchical Manufacturing (CMMI-1025020) and Office of Emerging Frontiers in Research and Innovation (EFRI-1433496).

  15. Raman spectroscopic studies on bacteria

    Science.gov (United States)

    Maquelin, Kees; Choo-Smith, Lin-P'ing; Endtz, Hubert P.; Bruining, Hajo A.; Puppels, Gerwin J.

    2000-11-01

    Routine clinical microbiological identification of pathogenic micro-organisms is largely based on nutritional and biochemical tests. Laboratory results can be presented to a clinician after 2 - 3 days for most clinically relevant micro- organisms. Most of this time is required to obtain pure cultures and enough biomass for the tests to be performed. In the case of severely ill patients, this unavoidable time delay associated with such identification procedures can be fatal. A novel identification method based on confocal Raman microspectroscopy will be presented. With this method it is possible to obtain Raman spectra directly from microbial microcolonies on the solid culture medium, which have developed after only 6 hours of culturing for most commonly encountered organisms. Not only does this technique enable rapid (same day) identifications, but also preserves the sample allowing it to be double-checked with traditional tests. This, combined with the speed and minimal sample handling indicate that confocal Raman microspectroscopy has much potential as a powerful new tool in clinical diagnostic microbiology.

  16. Raman Spectroscopic Investigation of Dyes in Spices

    Science.gov (United States)

    Uhlemann, Ute; Ramoji, Anuradha; Rösch, Petra; Da Costa Filho, Paulo Augusto; Robert, Fabien; Popp, Jürgen

    2010-08-01

    In this study, a number of synthetic colorants for spices have been investigated by means of Raman spectroscopy, resonance Raman spectroscopy, and surface enhanced (resonance) Raman spectroscopy (SER(S)). The aim of the study was the determination of limits of detection for each dye separately and in binary mixtures of dyes in spiked samples of the spices. Most of the investigated dyes have been azo dyes, some being water-soluble, the other being fat-soluble. Investigating the composition of food preparations is an ongoing and important branch of analytical sciences. On one hand, new ingredients have to be analyzed with regard to their contents, on the other hand, raw materials that have been tampered have to be eliminated from food production processes. In the last decades, the various Raman spectroscopic methods have proven to be successful in many areas of life and materials sciences. The ability of Raman spectroscopy to distinguish even structural very similar analytes by means of their vibrational fingerprint will also be important in this study. Nevertheless, Raman scattering is a very weak process that is oftentimes overlaid by matrix interferences or fluorescence. In order to achieve limits of detection in the nanomolar range, the signal intensity has to be increased. According to the well-known equations, there are several ways of achieving this increase: •increasing sample concentration •increasing laser power •decreasing the laser wavelength •using electronic resonance •increasing the local electromagnetic field In this study, nearly all of the above-mentioned principles were applied. In a first step, all dyes were investigated in solution at different concentrations to determine a limit of detection. In the second step, spiked spice samples have been extracted with a variety of solvents and process parameters tested. To lower the limit of detection even further, SERS spectroscopy has been used as well in as out of electronic resonance.

  17. Raman spectroscopic biochemical mapping of tissues

    Science.gov (United States)

    Stone, Nicholas; Hart Prieto, Maria C.; Kendall, Catherine A.; Shetty, Geeta; Barr, Hugh

    2006-02-01

    Advances in technologies have brought us closer to routine spectroscopic diagnosis of early malignant disease. However, there is still a poor understanding of the carcinogenesis process. For example it is not known whether many cancers follow a logical sequence from dysplasia, to carcinoma in situ, to invasion. Biochemical tissue changes, triggered by genetic mutations, precede morphological and structural changes. These can be probed using Raman or FTIR microspectroscopy and the spectra analysed for biochemical constituents. Local microscopic distribution of various constituents can then be visualised. Raman mapping has been performed on a number of tissues including oesophagus, breast, bladder and prostate. The biochemical constituents have been calculated at each point using basis spectra and least squares analysis. The residual of the least squares fit indicates any unfit spectral components. The biochemical distribution will be compared with the defined histopathological boundaries. The distribution of nucleic acids, glycogen, actin, collagen I, III, IV, lipids and others appear to follow expected patterns.

  18. Raman spectroscopic study of some chalcopyrite-xanthate flotation products

    CSIR Research Space (South Africa)

    Andreev, GN

    2003-12-16

    Full Text Available of normal vibrations of the corresponding individual compounds. The latter facilitated the Raman spectroscopic elucidation of the reaction products formed on the chalcopyrite surface in real industrial flotation conditions with a sodium isopropyl xanthate...

  19. Raman and surface enhanced Raman spectroscopic investigation on Lamiaceae plants

    Science.gov (United States)

    Rösch, P.; Popp, J.; Kiefer, W.

    1999-05-01

    The essential oils of Thymus vulgaris and Origanum vulgaris are studied by means of micro-Raman spectroscopy. The containing monoterpenes can be identified by their Raman spectra. Further the essential oils are investigated in their natural environment, the so-called oil cells of these Lamiaceae plants, with surface enhanced Raman spectroscopy (SERS). This method has the advantage to enhance Raman signals and furthermore the SERS effect leads to fluorescence quenching.

  20. Anti-Stokes shift luminescent materials for bio-applications.

    Science.gov (United States)

    Zhu, Xingjun; Su, Qianqian; Feng, Wei; Li, Fuyou

    2017-02-20

    Anti-Stokes shift luminescence is a special optical process, which converts long-wavelength excitation to short-wavelength emission. This unique ability is especially helpful for bio-applications, because the longer-wavelength light source, usually referring to near infrared light, has a larger penetration depth offering a longer working distance for in vivo applications. The anti-Stokes shift luminescence signal can also be distinguished from the auto-fluorescence of biological tissues, thus reducing background interference during bioimaging. Herein, we summarize recent advances in anti-Stokes shift luminescent materials, including lanthanide and triplet-triplet-annihilation-based upconversion nanomaterials, and newly improved hot-band absorption-based luminescent materials. We focus on the synthetic strategies, optical optimization and biological applications as well as present comparative discussions on the luminescence mechanisms and characteristics of these three types of luminescent materials.

  1. INFRARED AND RAMAN SPECTROSCOPIC STUDY OF ION ...

    African Journals Online (AJOL)

    Infrared and Raman spectroscopy techniques have been used to study the ionic interactions of strontium(II) and barium(II) with thiocyanate ion in liquid ammonia. A number of bands were observed in both n (CN) and n (CS) regions of infrared and Raman spectra and these were assigned to 1:1 contact ion pair, ...

  2. Resonance Raman spectroscopic investigation of MLCT character ...

    Indian Academy of Sciences (India)

    Administrator

    Resonance Raman spectroscopy, because of its utility in understanding resonant state dynamics and structure, is an ideal tool to investigate MLCT states of inorganic complexes. In particular, the tunability of the excitation wavelength and thus the resulting resonance Raman intensities provide information on the nuclear ...

  3. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Improved anti-Stokes energy transfer between rare earth ions in Er(0.5)Yb(9.5): FOV oxyfluoride vitroceramics explains the strong color reversal

    Science.gov (United States)

    Chen, Xiao-Bo; Wang, Ce; Gregory, Salamo J.; Naruhito, Sawanobori; Kang, Dong-Guo; Masaaki, Ohtsuka; Yang, Guo-Jian; Peng, Fang-Lin

    2009-12-01

    The widely used energy transfer theory is a foundation of luminescence, in which the rates of Stokes and anti-Stokes processes have the same calculation formula. An improvement on the anti-Stokes energy transfer to explain the fluorescence intensity reversal between the red and green fluorescence of Er(0.5)Yb(9.5):FOV is reported in the present article. The range of the intensity reversal σ was measured to be 877. Dynamic processes for 16 levels were simulated. A coefficient, the improvement factor of the intensity ratio of Stokes to anti-Stokes processes in quantum Raman theory compared to classical Raman theory, is introduced to successfully describe the anti-Stokes energy transfer. A new method to calculate the distance between the rare earth ions, which is critical for the energy transfer calculation, is proposed. The validity of these important improvements is also proved by experiment.

  4. Compact fibre-based coherent anti-Stokes Raman scattering ...

    Indian Academy of Sciences (India)

    Abstract. We demonstrate a new approach to CARS spectroscopy by efficiently syn- thesizing synchronized narrow-bandwidth (less than 10 cm−1) pump and Stokes pulses. (frequency difference continuously tunable upto ~3000 cm−1) based on spectral compres- sion together with second harmonic generation (in ...

  5. Compact fibre-based coherent anti-Stokes Raman scattering ...

    Indian Academy of Sciences (India)

    tral compression of femtosecond pulses emitted by a single highly compact fibre laser. Spectral compression of the broadband femtosecond pulses is achieved by generating narrow-band second harmonic (SH) pulses in crystals with large group- delay mismatch between the fundamental frequency (FF) and the SH pulses ...

  6. Compact fibre-based coherent anti-Stokes Raman scattering ...

    Indian Academy of Sciences (India)

    We demonstrate a new approach to CARS spectroscopy by efficiently synthesizing synchronized narrow-bandwidth (less than 10 cm-1) pump and Stokes pulses (frequency difference continuously tunable upto ∼ 3000 cm-1) based on spectral compression together with second harmonic generation (in periodically-poled ...

  7. Raman spectroscopic measurements on fluoromethane clathrate hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, T. [Hokkaido Univ., Sapporo (Japan). Graduate School of Engineering, Div. of Applied Physics; Ohmura, R. [Keio Univ., Kohoku-ku, Yokohama (Japan). Dept. of Mechanical Engineering; Hori, A. [Kitami Inst. of Technology, Kitami (Japan). Course of Civil Engineering

    2008-07-01

    The occupation of guest molecules in clathrate-structure cages is of interest to researchers, since this property is involved in the estimation of guest molecule density, the stability of clathrate hydrates, and other features. However, such occupation is known to be non-stoichiometric. It remains difficult to accurately estimate the total amount of natural gases in the hydrates located in the deep ocean or in permafrost. This paper discussed the systematic observations of fluoromethane clathrate hydrates using Raman spectroscopy in conjunction with previously obtained Raman spectra for methane (CH{sub 4}) hydrate. Four types of fluoromethane were utilized as standard guest molecules to investigate cage occupation in the hydrates, as all of them were included in the same crystal structure and shared similar functional groups. The types of fluoromethane that were used included fluoromethane (CH{sub 3}F), difluoromethane (CH{sub 2}F{sub 2}), trifluoromethane (CHF{sub 3}), and tetrafluoromethane (CF{sub 4}). The paper discussed the experimental methods including the temperature and pressure conditions of fluorocarbon hydrate formation. It was concluded that the summary of the Raman peak positions of fluoromethane molecules indicate that the influence of deuterized host molecules on the intramolecular vibration frequencies is less than that suggested by experimental error. The obtained data were confirmed to agree with the empirical model for the Raman peak positions on guest molecules, when the relative position of the guest molecule in a host cage structure is considered. 28 refs., 1 tab., 7 figs.

  8. Oral cancer screening: serum Raman spectroscopic approach

    Science.gov (United States)

    Sahu, Aditi K.; Dhoot, Suyash; Singh, Amandeep; Sawant, Sharada S.; Nandakumar, Nikhila; Talathi-Desai, Sneha; Garud, Mandavi; Pagare, Sandeep; Srivastava, Sanjeeva; Nair, Sudhir; Chaturvedi, Pankaj; Murali Krishna, C.

    2015-11-01

    Serum Raman spectroscopy (RS) has previously shown potential in oral cancer diagnosis and recurrence prediction. To evaluate the potential of serum RS in oral cancer screening, premalignant and cancer-specific detection was explored in the present study using 328 subjects belonging to healthy controls, premalignant, disease controls, and oral cancer groups. Spectra were acquired using a Raman microprobe. Spectral findings suggest changes in amino acids, lipids, protein, DNA, and β-carotene across the groups. A patient-wise approach was employed for data analysis using principal component linear discriminant analysis. In the first step, the classification among premalignant, disease control (nonoral cancer), oral cancer, and normal samples was evaluated in binary classification models. Thereafter, two screening-friendly classification approaches were explored to further evaluate the clinical utility of serum RS: a single four-group model and normal versus abnormal followed by determining the type of abnormality model. Results demonstrate the feasibility of premalignant and specific cancer detection. The normal versus abnormal model yields better sensitivity and specificity rates of 64 and 80% these rates are comparable to standard screening approaches. Prospectively, as the current screening procedure of visual inspection is useful mainly for high-risk populations, serum RS may serve as a useful adjunct for early and specific detection of oral precancers and cancer.

  9. Raman spectroscopic study of a genetically altered kidney cell

    Science.gov (United States)

    Joshi, Joel; Garcia, Francisco; Centeno, Silvia P.; Joshi, N. V.

    2008-02-01

    A Raman spectroscopic investigation of a genetically altered Human Embryonic Kidney Cell (HEK293) along with a pathologically normal cell has been carried out by a conventional method. The genetic alteration was carried out with a standard protocol by using a Green Fluorescence Protein (GFP). Raman spectra show that there are dramatic differences between the spectrum obtained from a genetically altered cell and that obtained from a pathologically normal cell. The former shows three broad bands; meanwhile the latter shows several sharp peaks corresponding to the ring vibrational modes of Phen, GFP and DNA. The present analysis provides an indication that the force field near Phen located at 64, 65 and 66 was altered during the genetic transformation. The Raman spectrum could be a direct experimental evidence for substantial modifications triggered due to the expression of specific genes.

  10. Rapid identification of single microbes by various Raman spectroscopic techniques

    Science.gov (United States)

    Rösch, Petra; Harz, Michaela; Schmitt, Michael; Peschke, Klaus-Dieter; Ronneberger, Olaf; Burkhardt, Hans; Motzkus, Hans-Walter; Lankers, Markus; Hofer, Stefan; Thiele, Hans; Popp, Jürgen

    2006-02-01

    A fast and unambiguous identification of microorganisms is necessary not only for medical purposes but also in technical processes such as the production of pharmaceuticals. Conventional microbiological identification methods are based on the morphology and the ability of microbes to grow under different conditions on various cultivation media depending on their biochemical properties. These methods require pure cultures which need cultivation of at least 6 h but normally much longer. Recently also additional methods to identify bacteria are established e.g. mass spectroscopy, polymerase chain reaction (PCR), flow cytometry or fluorescence spectroscopy. Alternative approaches for the identification of microorganisms are vibrational spectroscopic techniques. With Raman spectroscopy a spectroscopic fingerprint of the microorganisms can be achieved. Using UV-resonance Raman spectroscopy (UVRR) macromolecules like DNA/RNA and proteins are resonantly enhanced. With an excitation wavelength of e.g. 244 nm it is possible to determine the ratio of guanine/cytosine to all DNA bases which allows a genotypic identification of microorganisms. The application of UVRR requires a large amount of microorganisms (> 10 6 cells) e.g. at least a micro colony. For the analysis of single cells micro-Raman spectroscopy with an excitation wavelength of 532 nm can be used. Here, the obtained information is from all type of molecules inside the cells which lead to a chemotaxonomic identification. In this contribution we show how wavelength dependent Raman spectroscopy yields significant molecular information applicable for the identification of microorganisms on a single cell level.

  11. Monitoring the healing of combat wounds using Raman spectroscopic mapping.

    Science.gov (United States)

    Crane, Nicole J; Brown, Trevor S; Evans, Korboi N; Hawksworth, Jason S; Hussey, Sean; Tadaki, Doug K; Elster, Eric A

    2010-01-01

    Soldiers wounded in modern warfare present with extensive and complicated acute wounds, confounded by an overwhelming inflammatory response. The pathophysiology of acute wounds is unknown and timing of wound closure remains subjective. Collagen gene expression profiles are presented for 24 patients. Impaired healing wounds showed a twofold decrease in the up-regulation of COL1A1 and COL3A1 genes in the beginning of the wound healing process, compared with normal healing wounds. By the final debridement, however, collagen gene expression profiles for normal and impaired healing wounds were similar for COL1A1 and COL3A1. In addition, Raman spectroscopic maps were collected of biopsy tissue sections, from the first and last debridements of 10 wounds collected from nine patients. Tissue components obtained for the debridement biopsies were compared to elucidate whether or not a wound healed normally. Raman spectroscopy showed a loss of collagen in five patients, indicated by a negative percent difference in the 1,665/1,445 cm(-1) band area ratios. Four healed patients showed an increased or unchanged collagen content. Here, we demonstrate the potential of Raman spectroscopic analysis of wound biopsies for classification of wounds as normal or impaired healing. Raman spectroscopy has the potential to noninvasively monitor collagen deposition in the wound bed, during surgical wound debridements, to help determine the optimal time for wound closure.

  12. Raman spectroscopic study of cyclohexane at pressures below 1000 MPa

    Science.gov (United States)

    Qiao, Erwei; Zheng, Haifei

    2017-10-01

    At present, the room temperature freezing pressure of cyclohexane is still uncertain, and the phase transition pressure of solid I - solid III is not reliable at ambient temperature. In this work, we have performed a Raman spectroscopic study of cyclohexane in a Moissanite anvil cell at pressures below 1000 MPa at 25 °C, and analyzed the characteristic of Raman brands νs(CH2), νas(CH2) and νb(Ring). Two phase transition pressures 80 MPa and 550 MPa were determined by a quartz pressure gauge, and they are the room temperature freezing pressure of cyclohexane and the phase transition pressure of solid I to solid III, respectively. Furthermore, from the phase diagram of cyclohexane, it is inferred that pressure plays an important role on the stability of cyclohexane as the main constituent of oil, and it can be beneficial to understanding the formation, migration and preservation of petroleum in subterranean rock strata.

  13. [Raman spectroscopic study on silicone fluid as pressure gauge].

    Science.gov (United States)

    Liu, Jin; Sun, Qiang

    2010-09-01

    Within a diamond-anvil cell, the in-situ Raman spectroscopic study of silicone fluid was operated at room temperature 298. 1 K and under pressures from 0.1 to 5140.2 MPa. The present study analyzed the correlation of the modes 2906 and 2967 cm(-1) with different pressures, indicating that their wavenumbers linearly increased with increasing pressure. Therefore, this provided the potential to consider the pressure medium silicone fluid as a pressure gauge. The result suggested that silicone fluid could be used as a reliable pressure gauge in high-pressure experiments using diamond-anvil cells with Raman spectrometer, and the correlations between pressure and (delta nu p)2906, (delta nu p)2967 are, p = -0.05[(delta nu p)2967]2 + 73.07 (delta nu p)2967 + 91.54 and p = 0.14 [(delta nu p)2906]2 + 81.9 (delta nu p)2906 + 92.01, respectively.

  14. Raman spectroscopic study of "The Malatesta": a Renaissance painting?

    Science.gov (United States)

    Edwards, Howell G M; Vandenabeele, Peter; Benoy, Timothy J

    2015-02-25

    Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Raman spectroscopic analysis of a `noli me tangere' painting

    Science.gov (United States)

    Hibberts, Stephen; Edwards, Howell G. M.; Abdel-Ghani, Mona; Vandenabeele, Peter

    2016-12-01

    The discovery of an oil painting in seriously damaged condition with an important historical and a heterodox detail with possible origins in the late fifteenth century has afforded the opportunity for Raman microscopic analysis prior to its restoration being undertaken. The painting depicts a risen Christ following His crucifixion in a `noli me tangere' pose with three women in an Italian terrace garden with a stone balustrade overlooking a rural landscape and an undoubted view of late-medieval Florence. The picture has suffered much abuse and is in very poor condition, which is possibly attributable to its controversial portrayal of a polydactylic Christ with six toes on His right foot. By the late sixteenth century, after the Council of Trent, this portrayal would almost certainly have been frowned upon by the Church authorities or more controversially as a depiction of the holy. Raman spectroscopic analysis of the pigments places the painting as being consistent chronologically with the Renaissance period following the identification of cinnabar, haematite, red lead, lead white, goethite, verdigris, caput mortuum and azurite with no evidence of more modern synthetic pigments or of modern restoration having been carried out. An interesting pigment mixture found here is that of the organic dye carmine and cinnabar to produce a particular bright red pigment coloration. Stratigraphic examination of the paint fragments has demonstrated the presence of an orange resin layer immediately on top of the canvas substrate, effectively rendering the pigment as a sandwich between this substratal resin and the overlying varnish. The Raman spectroscopic evidence clearly indicates that an attribution of the artwork to the Renaissance is consistent with the scientific analysis of the pigment composition. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  16. Raman spectroscopic analysis of a 'noli me tangere' painting.

    Science.gov (United States)

    Hibberts, Stephen; Edwards, Howell G M; Abdel-Ghani, Mona; Vandenabeele, Peter

    2016-12-13

    The discovery of an oil painting in seriously damaged condition with an important historical and a heterodox detail with possible origins in the late fifteenth century has afforded the opportunity for Raman microscopic analysis prior to its restoration being undertaken. The painting depicts a risen Christ following His crucifixion in a 'noli me tangere' pose with three women in an Italian terrace garden with a stone balustrade overlooking a rural landscape and an undoubted view of late-medieval Florence. The picture has suffered much abuse and is in very poor condition, which is possibly attributable to its controversial portrayal of a polydactylic Christ with six toes on His right foot. By the late sixteenth century, after the Council of Trent, this portrayal would almost certainly have been frowned upon by the Church authorities or more controversially as a depiction of the holy. Raman spectroscopic analysis of the pigments places the painting as being consistent chronologically with the Renaissance period following the identification of cinnabar, haematite, red lead, lead white, goethite, verdigris, caput mortuum and azurite with no evidence of more modern synthetic pigments or of modern restoration having been carried out. An interesting pigment mixture found here is that of the organic dye carmine and cinnabar to produce a particular bright red pigment coloration. Stratigraphic examination of the paint fragments has demonstrated the presence of an orange resin layer immediately on top of the canvas substrate, effectively rendering the pigment as a sandwich between this substratal resin and the overlying varnish. The Raman spectroscopic evidence clearly indicates that an attribution of the artwork to the Renaissance is consistent with the scientific analysis of the pigment composition.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'. © 2016 The Author(s).

  17. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn

    2006-01-01

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration,...

  18. Microsecond Scale Vibrational Spectroscopic Imaging by Multiplex Stimulated Raman Scattering Microscopy

    OpenAIRE

    Liao, Chien-Sheng; Slipchenko, Mikhail N.; Wang, Ping; Li, Junjie; Lee, Seung-Young; Oglesbee, Robert A.; Cheng, Ji-Xin

    2015-01-01

    Real-time vibrational spectroscopic imaging is desired for monitoring cellular states and cellular processes in a label-free manner. Raman spectroscopic imaging of highly dynamic systems is inhibited by relatively slow spectral acquisition on millisecond to second scale. Here, we report microsecond scale vibrational spectroscopic imaging by lock-in free parallel detection of spectrally dispersed stimulated Raman scattering signal. Using a homebuilt tuned amplifier array, our method enables Ra...

  19. Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance

    Science.gov (United States)

    Edwards, Howell G. M.

    2011-10-01

    The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

  20. Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance.

    Science.gov (United States)

    Edwards, Howell G M

    2011-10-01

    The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope.

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10(-7) Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  2. Cutaneous porphyrins exhibit anti-stokes fluorescence that is detectable in sebum (Conference Presentation)

    Science.gov (United States)

    Tian, Giselle; Zeng, Haishan; Zhao, Jianhua; Wu, Zhenguo; Al Jasser, Mohammed; Lui, Harvey; Mclean, David I.

    2016-02-01

    Porphyrins produced by Propionibacterium acnes represent the principal fluorophore associated with acne, and appear as orange-red luminescence under the Wood's lamp. Assessment of acne based on Wood's lamp (UV) or visible light illumination is limited by photon penetration depth and has limited sensitivity for earlier stage lesions. Inducing fluorescence with near infrared (NIR) excitation may provide an alternative way to assess porphyrin-related skin disorders. We discovered that under 785 nm CW laser excitation PpIX powder exhibits fluorescence emission in the shorter wavelength range of 600-715 nm with an intensity that is linearly dependent on the excitation power. We attribute this shorter wavelength emission to anti-Stokes fluorescence. Similar anti-Stokes fluorescence was also detected focally in all skin-derived samples containing porphyrins. Regular (Stokes) fluorescence was present under UV and visible light excitation on ex vivo nasal skin and sebum from uninflamed acne, but not on nose surface smears or sebum from inflamed acne. Co-registered CW laser-excited anti-Stokes fluorescence and fs laser-excited multi-photon fluorescence images of PpIX powder showed similar features. In the skin samples because of the anti-Stokes effect, the NIR-induced fluorescence was presumably specific for porphyrins since there appeared to be no anti-Stokes emission signals from other typical skin fluorophores such as lipids, keratins and collagen. Anti-Stokes fluorescence under NIR CW excitation is more sensitive and specific for porphyrin detection than UV- or visible light-excited regular fluorescence and fs laser-excited multi-photon fluorescence. This approach also has higher image contrast compared to NIR fs laser-based multi-photon fluorescence imaging. The anti-Stokes fluorescence of porphyrins within sebum could potentially be applied to detecting and targeting acne lesions for treatment via fluorescence image guidance.

  3. Infrared and Raman Spectroscopic Study of Carbon-Cobalt Composites

    Directory of Open Access Journals (Sweden)

    André Tembre

    2011-01-01

    Full Text Available Analysis of carbon-cobalt thin films using infrared spectroscopy has shown existence of carbon-cobalt stretching mode and great porosity. The Raman spectroscopy and high-resolution transmission electron microscopy have been used in order to investigate the microstructure of the films. These films exhibit complex Raman spectra suggesting the presence of amorphous and crystallized phases. The different fractions of phases and the correlation between the atomic bond structures and the Raman features depend on the cobalt content.

  4. Infrared and Raman Spectroscopic Study of Carbon-Cobalt Composites

    OpenAIRE

    André Tembre; Jacques Hénocque; Martial Clin

    2011-01-01

    Analysis of carbon-cobalt thin films using infrared spectroscopy has shown existence of carbon-cobalt stretching mode and great porosity. The Raman spectroscopy and high-resolution transmission electron microscopy have been used in order to investigate the microstructure of the films. These films exhibit complex Raman spectra suggesting the presence of amorphous and crystallized phases. The different fractions of phases and the correlation between the atomic bond structures and the Raman feat...

  5. Raman spectroscopic characterization of multiwall carbon nanotubes and of composites

    Directory of Open Access Journals (Sweden)

    L. Bokobza

    2012-07-01

    Full Text Available In this work Raman spectroscopy was used for extensive characterization of multiwall carbon nanotube (MWNTs and of MWCNTs/rubber composites. We have measured the Raman spectra of bundled and dispersed multiwall carbon nanotubes. All the Raman bands of the carbon nanotubes are seen to shift to higher wavenumbers upon debundling on account of less intertube interactions. Effects of laser irradiation were also investigated. Strong effects are observed by changing the wavelength of the laser excitation. On the other hand, at a given excitation wavelength, changes on the Raman bands are observed by changing the laser power density due to sample heating during the measurement procedure.

  6. Raman spectroscopic analysis of real samples: Brazilian bauxite mineralogy

    Science.gov (United States)

    Faulstich, Fabiano Richard Leite; Castro, Harlem V.; de Oliveira, Luiz Fernando Cappa; Neumann, Reiner

    2011-10-01

    In this investigation, Raman spectroscopy with 1064 and 632.8 nm excitation was used to investigate real mineral samples of bauxite ore from mines of Northern Brazil, together with Raman mapping and X-rays diffraction. The obtained results show clearly that the use of microRaman spectroscopy is a powerful tool for the identification of all the minerals usually found in bauxites: gibbsite, kaolinite, goethite, hematite, anatase and quartz. Bulk samples can also be analysed, and FT-Raman is more adequate due to better signal-to-noise ratio and representativity, although not efficient for kaolinite. The identification of fingerprinting vibrations for all the minerals allows the acquisition of Raman-based chemical maps, potentially powerful tools for process mineralogy applied to bauxite ores.

  7. Two-Photon Infrared Resonance Can Enhance Coherent Raman Scattering

    Science.gov (United States)

    Traverso, Andrew J.; Hokr, Brett; Yi, Zhenhuan; Yuan, Luqi; Yamaguchi, Shoichi; Scully, Marlan O.; Yakovlev, Vladislav V.

    2018-02-01

    In this Letter we present a new technique for attaining efficient low-background coherent Raman scattering where the Raman coherence is mediated by a tunable infrared laser in two-photon resonance with a chosen vibrational transition. In addition to the traditional benefits of conventional coherent Raman schemes, this approach offers a number of advantages including potentially higher emission intensity, reduction of nonresonant four-wave mixing background, preferential excitation of the anti-Stokes field, and simplified phase matching conditions. In particular, this is demonstrated in gaseous methane along the ν1 (A1) and ν3 (T2) vibrational levels using an infrared field tuned between 1400 and 1600 cm-1 and a 532-nm pump field. This approach has broad applications, from coherent light generation to spectroscopic remote sensing and chemically specific imaging in microscopy.

  8. Spectroscopic Analysis of Neurotransmitters: A Theoretical and Experimental Raman Study

    Science.gov (United States)

    Alonzo, Matthew

    Surface-enhanced Raman spectroscopy (SERS) was applied to investigate the feasibility in the detection and monitoring of the dopamine (DA) neurotransmitter adsorbed onto silver nanoparticles (Ag NPs) at 10-11 molar, a concentration far below physiological levels. In addition, density functional theory (DFT) calculations were obtained with the Gaussian-09 analytical suite software to generate the theoretical molecular configuration of DA in its neutral, cationic, anionic, and dopaminequinone states for the conversion of computer-simulated Raman spectra. Comparison of theoretical and experimental results show good agreement and imply the presence of dopamine in all of its molecular forms in the experimental setting. The dominant dopamine Raman bands at 750 cm-1 and 795 cm-1 suggest the adsorption of dopaminequinone onto the silver nanoparticle surface. The results of this experiment give good insight into the applicability of using Raman spectroscopy for the biodetection of neurotransmitters.

  9. Infrared absorption and Raman scattering spectroscopic studies of condensed ions

    International Nuclear Information System (INIS)

    Dao, N.Q.; Knidiri, M.

    1975-01-01

    Infrared and Raman spectra of the complex K 5 (UO 2 ) 2 F 9 were recorded in the region 4000 to 80 cm -1 . Factor group analysis was used to classify the internal vibrations of the binuclear ion (UO 2 ) 2 F 9 5- . Infrared and Raman spectra were assigned and splitting of the internal modes of the (UO 2 ) 2 F 9 5- anion interpreted. (author)

  10. Stokes and anti-stokes stimulated Mie scattering on nanoparticle suspensions of latex

    Science.gov (United States)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-12-01

    Stokes and anti-Stokes shifts of stimulated concentration light scattering (SCLS, stimulated Mie scattering) in suspensions of various-sized latex nanoparticles in water were measured by the light guide scheme, under conditions of backscattering in the presence of convection.

  11. Raman Spectroscopic Methods for Classification of Normal and Malignant Hypopharyngeal Tissues: An Exploratory Study

    Directory of Open Access Journals (Sweden)

    Parul Pujary

    2011-01-01

    Full Text Available Laryngeal cancer is more common in males. The present study is aimed at exploration of potential of conventional Raman spectroscopy in classifying normal from a malignant laryngopharyngeal tissue. We have recorded Raman spectra of twenty tissues (aryepiglottic fold using an in-house built Raman setup. The spectral features of mean malignant spectrum suggests abundance proteins whereas spectral features of mean normal spectrum indicate redundancy of lipids. PCA was employed as discriminating algorithm. Both, unsupervised and supervised modes of analysis as well as match/mismatch “limit test” methodology yielded clear classification among tissue types. The findings of this study demonstrate the efficacy of conventional Raman spectroscopy in classification of normal and malignant laryngopharyngeal tissues. A rigorous evaluation of the models with development of suitable fibreoptic probe may enable real-time Raman spectroscopic diagnosis of laryngopharyngeal cancers in future.

  12. Raman spectroscopic analysis of Mexican natural artists' materials

    Science.gov (United States)

    Vandenabeele, Peter; Ortega-Avilès, Mayahuel; Castilleros, Dolores Tenorio; Moens, Luc

    2007-12-01

    This work represents the Raman spectra of 15 natural artists' materials that were obtained from local market in Mexico. Some of these products are not endemic to the region, but are often used in local conservation practice. Other materials are of local origin and have been used for centuries by local craftsmen. The Raman spectra that are reported here are: Chia oil, linseed oil, Campeche wax, beeswax, white copal, dammar, colophony, mastic, pixoy, chapopote, chucum, aje gum, gutta gum, peach gum and gum Arabic. The sample of pixoy was mixed with TiO 2, although it was not clear whether this was done intentionally or not. The Raman spectrum of chapopote, the local name for bitumen, contained features of carbonaceous and terpenoid matter. The Raman spectra of chapopote and chucum suffered severely from fluorescence, resulting in noisy Raman spectra. Aje gum and gutta gum are not gums, since they are resinous (terpenoid) in nature. Aje is a rare animal resin originating from Coccus axin.

  13. Raman spectroscopic study of plasma-treated salmon DNA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Joon; Kim, Yong Hee; Choi, Eun Ha [Plasma Bioscience Research Center, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of)

    2013-01-14

    In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

  14. Raman spectroscopic studies of lithium manganates with spinel structure

    CERN Document Server

    Julien, C M

    2003-01-01

    Raman scattering spectra of a set of lithium manganospinels Li sub 1 sub - sub x sub + sub z Mn sub 2 sub - sub z O sub 4 with 0 sup<= x sup<= 1 and 0 sup<= z sup<= 0.33 are reported and analysed. Structural changes have been investigated following the evolution of Raman spectra with the concentration of lithium cations. The local structure was characterized as a function of the mean oxidation state of manganese cations. The trigonal distortion of MnO sub 6 octahedra is evidenced by insertion of lithium ions into the [B sub 2]O sub 4 spinel framework. A comparison with tetragonal Mn sub 3 O sub 4 and Fe sub 3 O sub 4 spinels shows the influence of the Jahn-Teller effect on the Raman features for this class of materials.

  15. Fourier-transform Raman spectroscopic study of human hair

    Science.gov (United States)

    Akhtar, W.; Edwards, H. G. M.; Farwell, D. W.; Nutbrown, M.

    1997-07-01

    Fourier-transform Raman microscopic spectra of normal, untreated and bleached hair fibres are presented. Vibrational assignments are made and differences are ascribed to the production of cysteic acid from cysteine. Changes in conformation associated with the disulphide bond in the keratotic component are noted from the ν(CSSC) vibrational modes at wave numbers near 500 cm -1. Raman spectra of hair root ends have also been investigated with a diminution in cysteine content being observed. Application of the technique to the biomedical investigation of healthy and diseased hair is proposed.

  16. Raman spectroscopic determination of norbixin and tartrazine in sugar.

    Science.gov (United States)

    Uhlemann, Ute; Strelau, Katharina K; Weber, Karina; Da Costa Filho, Paulo Augusto; Rösch, Petra; Popp, Jürgen

    2012-08-01

    In this paper, a method for the detection of norbixin and tartrazine in sugar by means of resonance Raman spectroscopy is presented. The extraction was done in four steps using methanol and the measurements were performed in aqueous solution. The excitation wavelength was 514 nm for norbixin and 488 nm for tartrazine samples. The characteristic resonance Raman signals of the dyes were fitted by different functions. Depending on the R² values of the different fits, each spectrum was classified as positive or negative response. A detection limit of 250 ng g⁻¹ for norbixin and 989 ng g⁻¹ for tartrazine in solid sugar samples could be reached by logistic regression.

  17. Defects in individual semiconducting single wall carbon nanotubes: Raman spectroscopic and in situ Raman spectroelectrochemical study.

    Science.gov (United States)

    Kalbac, Martin; Hsieh, Ya-Ping; Farhat, Hootan; Kavan, Ladislav; Hofmann, Mario; Kong, Jing; Dresselhaus, Mildred S

    2010-11-10

    Raman spectroscopy and in situ Raman spectroelectrochemistry have been used to study the influence of defects on the Raman spectra of semiconducting individual single-walled carbon nanotubes (SWCNTs). The defects were created intentionally on part of an originally defect-free individual semiconducting nanotube, which allowed us to analyze how defects influence this particular nanotube. The formation of defects was followed by Raman spectroscopy that showed D band intensity coming from the defective part and no D band intensity coming from the original part of the same nanotube. It is shown that the presence of defects also reduces the intensity of the symmetry-allowed Raman features. Furthermore, the changes to the Raman resonance window upon the introduction of defects are analyzed. It is demonstrated that defects lead to both a broadening of the Raman resonance profile and a decrease in the maximum intensity of the resonance profile. The in situ Raman spectroelectrochemical data show a doping dependence of the Raman features taken from the defective part of the tested SWCNT.

  18. Raman spectroscopic characterization of wood and pulp fibers

    Science.gov (United States)

    Umesh Prasad Agarwal

    2008-01-01

    This chapter reviews applications of Raman spectroscopy in the field of wood and pulp fibers. Most of the literature examined was published between 1998 and 2006. In addition to introduction, this chapter contains sections on wood and components, mechanical pulp, chemical pulp, modified/treated wood, cellulose I crystallinity of wood fibers, and the self-absorption...

  19. Lanthanum trilactate: Vibrational spectroscopic study - infrared/Raman spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Švecová, M.; Novák, Vít; Bartůněk, V.; Člupek, M.

    2016-01-01

    Roč. 87, Nov (2016), s. 123-128 ISSN 0924-2031 Institutional support: RVO:61388963 Keywords : lanthanum trilactate * tris(2-hydroxypropanoato-O1,O2) * lanthanum tris[2-(hydroxy-kappa O)propanoato-kappa O] * Raman spectra * infrared spectra * DFT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.740, year: 2016

  20. Raman Spectroscopic Techniques for Planetary Exploration: Detecting Microorganisms through Minerals

    NARCIS (Netherlands)

    Verkaaik, M.F.C.; Hooijschuur, J.H.; Davies, G.R.; Ariese, F.

    2015-01-01

    Raman spectroscopy can provide highly specific chemical fingerprints of inorganic and organic materials and is therefore expected to play a significant role in interplanetary missions, especially for the search for life elsewhere in our solar system. A major challenge will be the unambiguous

  1. Raman spectroscopic study of solid solution spinel oxides

    Science.gov (United States)

    Hosterman, Brian D.

    Solid solution spinel oxides of composition MgxNi1-x Cr2O4, NiFexCr2-xO 4, and FexCr3-xO4 were synthesized and characterized using x-ray diffraction and Raman spectroscopy. Frequencies of the Raman-active modes are tracked as the metal cations within the spinel lattice are exchanged. This gives information about the dependence of the lattice vibrations on the tetrahedral and octahedral cations. The highest frequency Raman-active mode, A1g, is unaffected by substitution of the divalent tetrahedral cation, whereas the lower frequency vibrations are more strongly affected by substitution of the tetrahedral cation. The change in frequency of many phonons is nonlinear upon cation exchange. All detected modes of MgxNi1-xCr2O4 and FexCr3-xO4 exhibit one-mode behavior. Additional modes are detected in NiFexCr2-xO4 due to cation inversion of the spinel lattice. Results from the FexCr3-xO4 spinels are applied to identifying the corrosion layers of several stainless steel samples exposed to lead-bismuth eutectic in a high-temperature, oxygen controlled environment. The Raman spectrum of the outer corrosion layer in all steels is identified as Fe3O4. The position of the A 1g mode for the inner corrosion layer indicates an iron chromium spinel oxide. Micro-Raman spectroscopy proves capable of determining structural and compositional differences between complex corrosion layers of stainless steels.

  2. Raman spectroscopic study on the excystation process in a single unicellular organism amoeba (Acanthamoeba polyphaga)

    Science.gov (United States)

    Lin, Yu-Chung; Perevedentseva, Elena; Cheng, Chia-Liang

    2015-05-01

    An in vivo Raman spectroscopic study of amoeba (Acanthamoeba polyphaga) is presented. The changes of the spectra during the amoeba cyst activation and excystation are analyzed. The spectra show the changes of the relative intensities of bands corresponding to protein, lipid, and carotenoid components during cyst activation. The presence of carotenoids in the amoeba is observed via characteristic Raman bands. These signals in the Raman spectra are intense in cysts but decrease in intensity with cyst activation and exhibit a correlation with the life cycle of amoeba. This work demonstrates the feasibility of using Raman spectroscopy for the detection of single amoeba microorganisms in vivo and for the analysis of the amoeba life activity. The information obtained may have implications for the estimation of epidemiological situations and for the diagnostics and prognosis of the development of amoebic inflammations.

  3. Raman Spectroscopic Study on Decorative Glasses in Thailand

    International Nuclear Information System (INIS)

    Won-In, K.; Ponkrapan, S.; Dararutana, P.

    2011-01-01

    Glasses have been used as decorative objects in Thailand for several hundred years. Decorative glasses can generally be seen as architectural components in old styled palaces and Buddhist objects. There were various colors ranging from transparent to amber, blue, green and red with different shades among glass of different colors. Fragments of archaeological glass samples were characterized for the first time using Raman microscopy with the aim of obtaining information that would lead to identification of the glass samples by means of laser scattering. The samples were also investigated using other techniques, such as particle induced X-ray emission spectroscopy and scanning electron microscope operated with energy dispersive X-ray fluorescence spectrometer. They were mostly lead-silica based glasses. The colors resulted from metal ions. The difference in chemical composition was confirmed by Raman signature spectra. (author)

  4. Raman spectroscopic study of left-handed Z-RNA.

    Science.gov (United States)

    Trulson, M O; Cruz, P; Puglisi, J D; Tinoco, I; Mathies, R A

    1987-12-29

    The solvent conditions that induce the formation of a left-handed Z form of poly[r(G-C)] have been extended to include 6.5 M NaBr at 35 degrees C and 3.8 M MgCl2 at room temperature. The analysis of the A----Z transition in RNA by circular dichroism (CD), 1H and 31P NMR, and Raman spectroscopy shows that two distinct forms of left-handed RNA exist. The ZR-RNA structure forms in high concentrations of NaBr and NaClO4 and exhibits a unique CD signature. ZD-RNA is found in concentrated MgCl2 and has a CD signature similar to the Z form of poly[d(G-C)]. The loss of Raman intensity of the 813-cm-1 A-form marker band in both the A----ZR-RNA and A----ZD-RNA transitions parallels the loss of intensity at 835 cm-1 in the B----Z transition of DNA. A guanine vibration that is sensitive to the glycosyl torsion angle shifts from 671 cm-1 in A-RNA to 641 cm-1 in both ZD- and ZR-RNA, similar to the B----Z transition in DNA in which this band shifts from 682 to 625 cm-1. Significant differences in the glycosyl angle and sugar pucker between Z-DNA and Z-RNA are suggested by the 16-cm-1 difference in the position of this band. The Raman evidence for structural difference between ZD- and ZR-RNA comes from two groups of bands: First, Raman intensities between 1180 and 1600 cm-1 of ZD-RNA differ from those for ZR-RNA, corroborating the CD evidence for differences in base-stacking geometry. Second, the phosphodiester stretching bands near 815 cm-1 provide evidence of differences in backbone geometry between ZD- and ZR-RNA.

  5. HPLC assisted Raman spectroscopic studies on bladder cancer

    Science.gov (United States)

    Zha, W. L.; Cheng, Y.; Yu, W.; Zhang, X. B.; Shen, A. G.; Hu, J. M.

    2015-04-01

    We applied confocal Raman spectroscopy to investigate 12 normal bladder tissues and 30 tumor tissues, and then depicted the spectral differences between the normal and the tumor tissues and the potential canceration mechanism with the aid of the high-performance liquid chromatographic (HPLC) technique. Normal tissues were demonstrated to contain higher tryptophan, cholesterol and lipid content, while bladder tumor tissues were rich in nucleic acids, collagen and carotenoids. In particular, β-carotene, one of the major types of carotenoids, was found through HPLC analysis of the extract of bladder tissues. The statistical software SPSS was applied to classify the spectra of the two types of tissues according to their differences. The sensitivity and specificity of 96.7 and 66.7% were obtained, respectively. In addition, different layers of the bladder wall including mucosa (lumps), muscle and adipose bladder tissue were analyzed by Raman mapping technique in response to previous Raman studies of bladder tissues. All of these will play an important role as a directive tool for the future diagnosis of bladder cancer in vivo.

  6. Polarized Raman spectroscopic characterization of normal and oral cancer blood plasma

    Science.gov (United States)

    Pachaiappan, Rekha; Prakasarao, Aruna; Singaravelu, Ganesan

    2017-02-01

    In India oral cancer ranks the top due to the habitual usage of tobacco in its various forms and remains the major burden. Hence priority is given for early diagnosis as it is the better solution for cure or to improve the survival rate. For the past three decades, optical spectroscopic techniques have shown its capacity in the discrimination of normal and malignant samples. Many research works have conventional Raman in the effective detection of cancer using the variations in bond vibrations of the molecules. However in addition polarized Raman provides the orientation and symmetry of biomolecules. If so can polarized Raman be the better choice than the conventional Raman in the detection of cancer? The present study aimed to found the answer for the above query. The conventional and polarized Raman spectra were acquired for the same set of blood plasma samples of normal subjects and oral malignant (OSCC) patients. Thus, obtained Raman spectral data were compared using linear discriminant analysis coupled with artificial neural network (LDA-ANN). The depolarization ratio of biomolecules such as antioxidant, amino acid, protein and nucleic acid bases present in blood plasma was proven to be the best attributes in the categorization of the groups. The polarized Raman results were promising in discriminating oral cancer blood plasma from that of normal blood plasma with improved efficiency. The results will be discussed in detail.

  7. Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.

    Science.gov (United States)

    Padmaja, G; Kistaiah, P

    2009-03-19

    A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition.

  8. Method and system to measure temperature of gases using coherent anti-stokes doppler spectroscopy

    Science.gov (United States)

    Rhodes, Mark

    2013-12-17

    A method of measuring a temperature of a noble gas in a chamber includes providing the noble gas in the chamber. The noble gas is characterized by a pressure and a temperature. The method also includes directing a first laser beam into the chamber and directing a second laser beam into the chamber. The first laser beam is characterized by a first frequency and the second laser beam is characterized by a second frequency. The method further includes converting at least a portion of the first laser beam and the second laser beam into a coherent anti-Stokes beam, measuring a Doppler broadening of the coherent anti-Stokes beam, and computing the temperature using the Doppler broadening.

  9. Raman spectroscopic studies on exfoliated cells of oral and cervix

    Science.gov (United States)

    Hole, Arti; Sahu, Aditi; Shaikh, Rubina; Tyagi, Gunjan; Murali Krishna, C.

    2018-01-01

    Visual inspection followed by biopsy is the standard procedure for cancer diagnosis. Due to invasive nature of the current diagnostic methods, patients are often non-compliant. Hence, it is necessary to explore less invasive and rapid methods for early detection. Exfoliative cytology is a simple, rapid, and less invasive technique. It is thus well accepted by patients and is suitable for routine applications in population screening programs. Raman spectroscopy (RS) has been increasingly explored for disease diagnosis in the recent past. In vivo RS has previously shown promise in management of both oral and cervix cancers. In vivo applications require on-site instrumentation and stringent experimental conditions. Hence, RS of less invasive samples like exfoliated cells has been explored, as this facilitates collection at multiple screening centers followed by analysis at a centralized facility. In the present study, efficacy of Raman spectroscopy in classification of 15 normal and 29 abnormal oral exfoliated cells specimens and 28 normal and 38 abnormal cervix specimens were explored. Spectra were acquired by Raman microprobe (HE 785, Horiba-Jobin-Yvon, France) from several areas to span the pellet. Spectral acquisition parameters were: microscopic objective: 40X, power: 40 mW, acquisition time: 15 s and average: 3. PCA and PC-LDA of pre-processed spectra was carried out on a 4-model system of normal and tumor of both cervix and oral specimens. Leave-one-out-cross-validation findings indicate 73 % correct classification. Findings suggest RS of exfoliated cells may serve as a patient-friendly, non-invasive, rapid and objective method for management of cervix and oral cancers.

  10. Raman spectroscopic study of left-handed Z-RNA

    International Nuclear Information System (INIS)

    Trulson, M.O.; Cruz, P.; Puglisi, J.D.; Tinoco, I. Jr.; Mathies, R.A.

    1987-01-01

    The solvent conditions that induce the formation of a left-handed Z form of poly[r(G-C)] have been extended to include 6.5 M NaBr at 35 0 C and 3.8 M MgCl 2 at room temperature. The analysis of the A → Z transition in RNA by circular dichroism (CD), 1 H and 31 P NMR, and Raman spectroscopy shows that two distinct forms of left-handed RNA exist. The Z/sub R/-RNA structure forms in high concentrations of NaBr and NaClO 4 and exhibits a unique CD signature. Z/sub D/-RNA is found in concentrated MgCl 2 and has a CD signature similar to the Z form of poly[d(G-C)]. Significant differences in the glycosyl angle and sugar pucker between Z-DNA and Z-RNA are suggested by the 16-cm -1 difference in the position of this band. The Raman evidence for structural difference between Z/sub D/- and Z/sub R/-RNA comes from two groups of bands: First, Raman intensities between 1180 and 1600 cm -1 of Z/sub D/-RNA differ from those for Z/sub R/-RNA, corroborating the CD evidence for differences in base-stacking geometry. Second, the phosphodiester stretching bands near 815 cm -1 provide evidence of differences in backbone geometry between Z/sub D-/ and Z/sub R/-RNA

  11. Classification of inflammatory bowel diseases by means of Raman spectroscopic imaging of epithelium cells

    Science.gov (United States)

    Bielecki, Christiane; Bocklitz, Thomas W.; Schmitt, Michael; Krafft, Christoph; Marquardt, Claudio; Gharbi, Akram; Knösel, Thomas; Stallmach, Andreas; Popp, Juergen

    2012-07-01

    We report on a Raman microspectroscopic characterization of the inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC). Therefore, Raman maps of human colon tissue sections were analyzed by utilizing innovative chemometric approaches. First, support vector machines were applied to highlight the tissue morphology (=Raman spectroscopic histopathology). In a second step, the biochemical tissue composition has been studied by analyzing the epithelium Raman spectra of sections of healthy control subjects (n=11), subjects with CD (n=14), and subjects with UC (n=13). These three groups exhibit significantly different molecular specific Raman signatures, allowing establishment of a classifier (support-vector-machine). By utilizing this classifier it was possible to separate between healthy control patients, patients with CD, and patients with UC with an accuracy of 98.90%. The automatic design of both classification steps (visualization of the tissue morphology and molecular classification of IBD) paves the way for an objective clinical diagnosis of IBD by means of Raman spectroscopy in combination with chemometric approaches.

  12. Microsecond Scale Vibrational Spectroscopic Imaging by Multiplex Stimulated Raman Scattering Microscopy.

    Science.gov (United States)

    Liao, Chien-Sheng; Slipchenko, Mikhail N; Wang, Ping; Li, Junjie; Lee, Seung-Young; Oglesbee, Robert A; Cheng, Ji-Xin

    Real-time vibrational spectroscopic imaging is desired for monitoring cellular states and cellular processes in a label-free manner. Raman spectroscopic imaging of highly dynamic systems is inhibited by relatively slow spectral acquisition on millisecond to second scale. Here, we report microsecond scale vibrational spectroscopic imaging by lock-in free parallel detection of spectrally dispersed stimulated Raman scattering signal. Using a homebuilt tuned amplifier array, our method enables Raman spectral acquisition, within the window defined by the broadband pulse, at the speed of 32 microseconds and with close to shot-noise limited detection sensitivity. Incorporated with multivariate curve resolution analysis, our platform allows compositional mapping of lipid droplets in single live cells, observation of intracellular retinoid metabolism, discrimination of fat droplets from protein-rich organelles in Caenorhabditis elegans, spectral detection of fast flowing tumor cells, and monitoring drug diffusion through skin tissue in vivo . The reported technique opens new opportunities for compositional analysis of cellular compartment in a microscope setting and high-throughput spectral profiling of single cells in a flow cytometer setting.

  13. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  14. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Nobrega

    2012-01-01

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  15. Doping of C60 fullerene peapods with lithium: Raman spectroscopic and Raman spectroelectrochemical studies

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, L.

    2008-01-01

    Roč. 14, č. 20 (2008), s. 6231-5236 ISSN 0947-6539 R&D Projects: GA AV ČR KJB400400601 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * fullerenes * lithium * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 5.454, year: 2008

  16. Doping of C-70 fullerene peapods with lithium vapor: Raman spectroscopic and Raman spectroelectrochemical studies

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Valeš, Václav; Kavan, Ladislav; Dunsch, L.

    2014-01-01

    Roč. 25, č. 48 (2014), 485706 ISSN 0957-4484 R&D Projects: GA ČR GAP204/10/1677 Institutional support: RVO:61388955 Keywords : fullerene peapods * Raman spectroelectrochemistry * Li doping Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.821, year: 2014

  17. Simulation and analysis of spectroscopic filter of rotational Raman lidar for absolute measurement of atmospheric temperature

    Science.gov (United States)

    Li, Qimeng; Li, Shichun; Hu, Xianglong; Zhao, Jing; Xin, Wenhui; Song, Yuehui; Hua, Dengxin

    2018-01-01

    The absolute measurement technique for atmospheric temperature can avoid the calibration process and improve the measurement accuracy. To achieve the rotational Raman temperature lidar of absolute measurement, the two-stage parallel multi-channel spectroscopic filter combined a first-order blazed grating with a fiber Bragg grating is designed and its performance is tested. The parameters and the optical path structure of the core cascaded-device (micron-level fiber array) are optimized, the optical path of the primary spectroscope is simulated and the maximum centrifugal distortion of the rotational Raman spectrum is approximately 0.0031 nm, the centrifugal ratio of 0.69%. The experimental results show that the channel coefficients of the primary spectroscope are 0.67, 0.91, 0.67, 0.75, 0.82, 0.63, 0.87, 0.97, 0.89, 0.87 and 1 by using the twelfth channel as a reference and the average FWHM is about 0.44 nm. The maximum deviation between the experimental wavelength and the theoretical value is approximately 0.0398 nm, with the deviation degree of 8.86%. The effective suppression to elastic scattering signal are 30.6, 35.2, 37.1, 38.4, 36.8, 38.2, 41.0, 44.3, 44.0, 46.7 dB. That means, combined with the second spectroscope, the suppression at least is up to 65 dB. Therefore we can fine extract single rotational Raman line to achieve the absolute measurement technique.

  18. Raman spectroscopic identification of scytonemin and its derivatives as key biomarkers in stressed environments.

    Science.gov (United States)

    Varnali, Tereza; Edwards, Howell G M

    2014-12-13

    Raman spectroscopy has been identified as an important first-pass analytical technique for deployment on planetary surfaces as part of a suite of instrumentation in projected remote space exploration missions to detect extant or extinct extraterrestrial life signatures. Aside from the demonstrable advantages of a non-destructive sampling procedure and an ability to record simultaneously the molecular signatures of biological, geobiological and geological components in admixture in the geological record, the interrogation and subsequent interpretation of spectroscopic data from these experiments will be critically dependent upon the recognition of key biomolecular markers indicative of life existing or having once existed in extreme habitats. A comparison made with the characteristic Raman spectral wavenumbers obtained from standards is not acceptable because of shifts that can occur in the presence of other biomolecules and their host mineral matrices. In this paper, we identify the major sources of difficulty experienced in the interpretation of spectroscopic data centring on a key family of biomarker molecules, namely scytonemin and its derivatives; the parent scytonemin has been characterized spectroscopically in cyanobacterial colonies inhabiting some of the most extreme terrestrial environments and, with the support of theoretical calculations, spectra have been predicted for the characterization of several of its derivatives which could occur in novel extraterrestrial environments. This work will form the foundation for the identification of novel biomarkers and for their Raman spectroscopic discrimination, an essential step in the interpretation of potentially complex and hitherto unknown biological radiation protectants based on the scytoneman and scytonin molecular skeletons which may exist in niche geological scenarios in the surface and subsurface of planets and their satellites in our Solar System. © 2014 The Author(s) Published by the Royal Society

  19. Remote detection of chem/bio hazards via coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    2017-09-12

    Department of Physics & Engineering Physics Stevens Institute of Technology Hobokcn1 L J 07030 Ph.: (201) 216-8094, (734) 717-3604 Fa,x: (201) 216-5638...asynunetTic 2942 crri-1 (88.20THz) st.retch mode. The frequency of these viba1- tional modes is slightly different allowing to test t he chemical

  20. An integrated coherent anti-Stokes Raman scattering and multiphoton imaging technique for liver disease diagnosis

    Science.gov (United States)

    Lin, Jian; Lu, Fake; Zheng, Wei; Yu, Hanry; Sheppard, Colin; Huang, Zhiwei

    2012-03-01

    Liver steatosis and fibrosis are two prevalence liver diseases and may eventually develop into hepatocellular carcinoma (HCC) Due to their prevalence and severity, much work has been done to develop efficient diagnostic methods and therapies. Nonlinear optical microscopy has high sensitivity and chemical specificity for major biochemical compounds, making it a powerful tool for tissue imaging without staining. In this study, three nonlinear microscopy imaging modalities are applied to the study of liver diseases in a bile duct ligation rat modal. CARS shows the distributions of fats or lipids quantitatively across the tissue; SHG visualizes the collagens; and TPEF reveals the morphology of hepatic cells. The results clearly show the development of liver steatosis and fibrosis with time, and the hepatic fat and collagen fibrils are quantified. This study demonstrates the ability of multimodal nonlinear optical microscopy for liver disease diagnosis, and may provide new insights into the understanding of the mechanisms of steatosis/fibrosis transformations at the cellular and molecular levels.

  1. In situ dissolution analysis using coherent anti-Stokes Raman scattering (CARS) and hyperspectral CARS microscopy

    NARCIS (Netherlands)

    Fussell, A.L.; Garbacik, E.T.; Offerhaus, Herman L.; Kleinebudde, Peter; Strachan, Clare

    2013-01-01

    The solid-state form of an active pharmaceutical ingredient (API) in an oral dosage form plays an important role in determining the dissolution rate of the API. As the solid-state form can change during dissolution, there is a need to monitor the oral dosage form during dissolution testing. Coherent

  2. Analysis of detection limit to time-resolved coherent anti-Stokes Raman scattering nanoscopy

    International Nuclear Information System (INIS)

    Liu Wei; Liu Shuang-Long; Chen Dan-Ni; Niu Han-Ben

    2014-01-01

    In the implementation of CARS nanoscopy, signal strength decreases with focal volume size decreasing. A crucial problem that remains to be solved is whether the reduced signal generated in the suppressed focal volume can be detected. Here reported is a theoretical analysis of detection limit (DL) to time-resolved CARS (T-CARS) nanoscopy based on our proposed additional probe-beam-induced phonon depletion (APIPD) method for the low concentration samples. In order to acquire a detailed shot-noise limited signal-to-noise (SNR) and the involved parameters to evaluate DL, the T-CARS process is described with full quantum theory to estimate the extreme power density levels of the pump and Stokes beams determined by saturation behavior of coherent phonons, which are both actually on the order of ∼ 10 9 W/cm 2 . When the pump and Stokes intensities reach such values and the total intensity of the excitation beams arrives at a maximum tolerable by most biological samples in a certain suppressed focal volume (40-nm suppressed focal scale in APIPD method), the DL correspondingly varies with exposure time, for example, DL values are 10 3 and 10 2 when exposure times are 20 ms and 200 ms respectively. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. FTIR and Raman spectroscopic studies of selenium nanoparticles synthesised by the bacterium Azospirillum thiophilum

    Science.gov (United States)

    Tugarova, Anna V.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Kamnev, Alexander A.

    2018-03-01

    Vibrational (Fourier transform infrared (FTIR) and Raman) spectroscopic techniques can provide unique molecular-level information on the structural and compositional characteristics of complicated biological objects. Thus, their applications in microbiology and related fields are steadily increasing. In this communication, biogenic selenium nanoparticles (Se NPs) were obtained via selenite (SeO32-) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed the Se NPs to have average diameters within 160-250 nm; their zeta potential was measured to be minus 18.5 mV. Transmission FTIR spectra of the Se NPs separated from bacterial cells showed typical proteinacious, polysaccharide and lipid-related bands, in line with TEM data showing a thin layer covering the Se NPs surface. Raman spectra of dried Se NPs layer in the low-frequency region (under 500 cm-1 down to 150 cm-1) showed a single very strong band with a maximum at 250 cm-1 which, in line with its increased width (ca. 30 cm-1 at half intensity), can be attributed to amorphous elementary Se. Thus, a combination of FTIR and Raman spectroscopic approaches is highly informative in non-destructive analysis of structural and compositional properties of biogenic Se NPs.

  4. Defects in Individual Semiconducting Single Wall Carbon Nanotubes: Raman Spectroscopic and in Situ Raman Spectroelectrochemical Study

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Hsieh, Y. P.; Farhat, H.; Kavan, Ladislav; Hofmann, M.; Kong, J.; Dresselhaus, M. S.

    2010-01-01

    Roč. 10, č. 11 (2010), s. 4619-4626 ISSN 1530-6984 R&D Projects: GA ČR GC203/07/J067; GA AV ČR IAA400400804; GA AV ČR IAA400400911; GA AV ČR KAN200100801; GA MŠk ME09060 Institutional research plan: CEZ:AV0Z40400503 Keywords : single wall carbon nanotubes * Raman spectroscopy * defects Subject RIV: CG - Electrochemistry Impact factor: 12.186, year: 2010

  5. Doping of C70 fullerene peapods with lithium vapor: Raman spectroscopic and Raman spectroelectrochemical studies

    Science.gov (United States)

    Kalbáč, Martin; Vales, Vaclav; Kavan, Ladislav; Dunsch, Lothar

    2014-12-01

    Raman spectroscopy and in situ Raman spectroelectrochemistry were applied to study the lithium vapor doping of C70@SWCNTs (peapods). A strong degree of doping was proved by the vanishing of the single walled carbon nanotubes (SWCNT’s) radial breathing mode (RBM) and by the attenuation of the tangential (TG) band intensity. In contrast to potassium vapor doping, the strong downshift of the frequency of the TG band has not been observed for Li-doping. The Li vapor treated peapods remained partly doped even if they were exposed to humid air. This has been reflected by a reduced intensity of the nanotube and the fullerene modes and by the change of the shape of the RBM band as compared to that of the undoped sample. The modes of the intratubular fullerene were almost unresolved after the contact of the Li-doped sample with water. A lithium insertion into the interior of a peapod and its strong interaction with the intratubular fullerene is suggested to be responsible for the air-insensitive residual doping. This residual doping was studied by spectroelectrochemical measurements. The TG band of the Li doped peapods is partly upshifted during the anodic doping, which points to the different state of C70@SWCNTs and C60@SWCNTs studied previously.

  6. Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid

    Science.gov (United States)

    Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

    2015-03-01

    Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

  7. Combined FT-Raman spectroscopic and mass spectrometric study of ancient Egyptian sarcophagal fragments.

    Science.gov (United States)

    Edwards, Howell G M; Stern, Ben; Villar, Susana E Jorge; David, A Rosalie

    2007-02-01

    The application of combined Raman spectroscopic and GC-MS analytical techniques for the characterisation of organic varnish residues from Egyptian Dynastic funerary sarcophagal and cartonnage fragments from the Graeco-Roman period, ca. 2200 BP, is described. The nondestructive use of Raman spectroscopy was initially employed to derive information about the specific location of organic material on the specimens, which were then targeted in specific areas using minimal sampling for GC-MS analysis. In the case of the sarcophagal fragment, a degraded yellow-brown surface treatment was identified as a Pistacia spp. resin; this provides additional evidence for the use of this resin, which has previously been identified in Canaanite transport amphorae, varnishes and "incense" bowls in an Egyptian Late Bronze Age archaeological context. The cartonnage fragment also contained an organic coating for which the Raman spectrum indicated a degradation that was too severe to facilitate identification, but the GC-MS data revealed that it was composed of a complex mixture of fatty acid residues. The combined use of GC-MS and Raman spectroscopy for the characterisation of organic materials in an archaeological context is advocated for minimisation of sampling and restriction to specifically identified targets for museum archival specimens.

  8. Raman spectroscopic monitoring of the bioeffects of nitroglycerin on Hb-O II in single red blood cell

    Science.gov (United States)

    Chiang, Huihua Kenny; Ruan, Hung-Shiang; Cheng, Hung-You; Fang, Tung-Ting

    2007-02-01

    Raman spectroscopy has been shown to have the potential for providing oxygenated ability of erythrocytes. Raman line at 1638 cm-1 has also been reported as one significant oxygenic indicator for erythrocytes. In this research, we develop the Raman spectroscopic monitoring of the bioeffects of Nitroglycerin on hemoglobin oxygen saturation in a single red blood cell (RBC). Nitroglycerin has been frequently used in the management of angina pectoris. Nitroglycerin liberates nitric oxide (NO) to blood vessels. NO is an oxidizer that easily converts hemoglobin to methemoglobin. The conversion may cause the decrease of oxygenated ability of erythrocytes. In this study, we observed the oxidize state of erythrocytes caused by the over dosage of Nitroglycerin. When the dose of Nitroglycerin exceeds 2x10 -4 M, the oxygenic state of erythrocytes decreases significantly. The Raman spectroscopic results demonstrate the observation of the bioeffects of Nitroglycerin on hemoglobin.

  9. Raman spectroscopic analysis of phase-transformation and stress patterns in zirconia hip joints.

    Science.gov (United States)

    Pezzotti, Giuseppe; Porporati, Alessandro A

    2004-01-01

    Confocal Raman piezo-spectroscopy has been used for the quantitative assessments of phase transformation and residual stresses in zirconia made artificial hip joints. This work can be considered to be a first step towards the development of a fully quantitative technique for the spectroscopic characterization of zirconia femoral heads and other zirconia parts for biomedical applications. After establishing reliable calibration procedures, Raman microprobe spectroscopy could be extended to provide quantitative assessments of zirconia metastability and microscopic stress fields along the z axis perpendicular to the joint surface. For the first time, we have directly visualized patterns of phase-transformation and related residual stresses on the very surface and along the subsurface of both in vitro tested and retrieved hip implants. These spectroscopic assessments may open a completely new perspective in understanding the micromechanical wear behavior of zirconia ceramics in biological environment and in developing new zirconia-based biomaterials with superior stability characteristics. (c) 2004 Society of Photo-Optical Instrumentation Engineers.

  10. Multifunctional optofluidic lab-on-chip platform for Raman and fluorescence spectroscopic microfluidic analysis.

    Science.gov (United States)

    Persichetti, G; Grimaldi, I A; Testa, G; Bernini, R

    2017-07-25

    A multifunctional lab-on-a-chip platform for spectroscopic analysis of liquid samples based on an optofluidic jet waveguide is reported. The optofluidic detection scheme is achieved through the total internal reflection arising in a liquid jet of only 150 μm diameter, leading to highly efficient signal excitation and collection. This results in an optofluidic chip with an alignment-free spectroscopic detection scheme, which avoids any background from the sample container. This platform has been designed for multiwavelength fluorescence and Raman spectroscopy. The chip integrates a recirculation system that reduces the required sample volume. The evaluation of the device performance has been accomplished by means of fluorescence measurements performed on eosin Y in water solutions, achieving a limit of detection of 33 pM. The sensor has been applied in Raman spectroscopy of water-ethanol solutions, leading to a limit of detection of 0.18%. As additional application, analysis of riboflavin using fluorescence detection demonstrates the possibility of detecting this vitamin at the 560 pM level (0.21 ng l -1 ). Although measurements have been performed by means of a compact and low-cost spectrometer, in both cases the micro-jet optofluidic chip achieved similar performances if not better than high-end benchtop based laboratory equipment. This approach paves the way towards portable lab-on-a-chip devices for high sensitivity environmental and biochemical sensing, using optical spectroscopy.

  11. Raman spectroscopic analysis of human tissue engineered oral mucosa constructs (EVPOME) perturbed by physical and biochemical methods

    Science.gov (United States)

    Khmaladze, Alexander; Ganguly, Arindam; Raghavan, Mekhala; Kuo, Shiuhyang; Cole, Jacqueline H.; Marcelo, Cynthia L.; Feinberg, Stephen E.; Izumi, Kenji; Morris, Michael D.

    2012-01-01

    We show the application of near-infrared Raman Spectroscopy to in-vitro monitoring of the viability of tissue constructs (EVPOMEs). During their two week production period EVPOME may encounter thermal, chemical or biochemical stresses that could cause development to cease, rendering the affected constructs useless. We discuss the development of a Raman spectroscopic technique to study EVPOMEs noninvasively, with the ultimate goal of applying it in-vivo. We identify Raman spectroscopic failure indicators for EVPOMEs, which are stressed by temperature, and discuss the implications of varying calcium concentration and pre-treatment of the human keratinocytes with Rapamycin. In particular, Raman spectra show correlation of the peak height ratios of CH2 deformation to phenylalanine ring breathing, providing a Raman metric to distinguish between viable and nonviable constructs. We also show the results of singular value decomposition analysis, demonstrating the applicability of Raman spectroscopic technique to both distinguish between stressed and non-stressed EVPOME constructs, as well as between EVPOMEs and bare AlloDerm® substrates, on which the oral keratinocytes have been cultured. We also discuss complications arising from non-uniform thickness of the AlloDerm® substrate and the cultured constructs, as well as sampling protocols used to detect local stress and other problems that may be encountered in the constructs.

  12. Swiss bare mice: a suitable model for transcutaneous in vivo Raman spectroscopic studies of breast cancer.

    Science.gov (United States)

    Bhattacharjee, T; Kumar, Piyush; Maru, G; Ingle, A; Krishna, C Murali

    2014-01-01

    Breast cancer is the most common cancer affecting females worldwide. As early detection results in better prognosis, screening tools for breast cancer are being explored. Raman spectroscopy, a rapid, objective, and noninvasive tool, has shown promising results in the diagnosis of several cancers including breast cancer. For development as a screening tool, a study of spectral signatures associated with breast cancer progression is imperative. However, such studies are not possible in human subjects. Hence, there is a need for a suitable animal model, which is conducive to transcutaneous in vivo Raman spectroscopic measurements of breast with minimal interference from skin and hair and has contribution from functional mammary epithelium of breast. In this study, rodent models like C57, Swiss albino, Swiss bare, agouti mice, and Sprague-Dawley rats were evaluated. Among these models, transcutaneous breast spectra of hairless Swiss bare mice have the best signal-to-noise ratio and were closest to reported ex vivo as well as intraoperative in vivo human breast spectra. Principal component-linear discriminant analysis of several anatomical sites confirms minimal skin interference and suggests contribution from functional mammary epithelium of breast. Moreover, transcutaneous spectra from normal breast and breast tumors of Swiss bare mice could be classified with 99% efficiency, which is better than the previous reports. Thus, Swiss bare mice model may be better suited for transcutaneous in vivo Raman spectroscopic studies of breast physiology and pathology, especially breast cancer. Prospectively, in addition to cancer progression, breast-to-bone metastasis can also be studied, since these anatomical sites can be uniquely classified.

  13. In vivo Raman spectroscopic identification of premalignant lesions in oral buccal mucosa

    Science.gov (United States)

    Singh, S. P.; Deshmukh, Atul; Chaturvedi, Pankaj; Murali Krishna, C.

    2012-10-01

    Cancers of oral cavities are one of the most common malignancies in India and other south-Asian countries. Tobacco habits are the main etiological factors for oral cancer. Identification of premalignant lesions is required for improving survival rates related to oral cancer. Optical spectroscopy methods are projected as alternative/adjunct for cancer diagnosis. Earlier studies have demonstrated the feasibility of classifying normal, premalignant, and malignant oral ex-vivo tissues. We intend to evaluate potentials of Raman spectroscopy in detecting premalignant conditions. Spectra were recorded from premalignant patches, contralateral normal (opposite to tumor site), and cancerous sites of subjects with oral cancers and also from age-matched healthy subjects with and without tobacco habits. A total of 861 spectra from 104 subjects were recorded using a fiber-optic probe-coupled HE-785 Raman spectrometer. Spectral differences in the 1200- to 1800-cm-1 region were subjected to unsupervised principal component analysis and supervised linear discriminant analysis followed by validation with leave-one-out and an independent test data set. Results suggest that premalignant conditions can be objectively discriminated with both normal and cancerous sites as well as from healthy controls with and without tobacco habits. Findings of the study further support efficacy of Raman spectroscopic approaches in oral-cancer applications.

  14. RAMAN SPECTROSCOPIC STUDY ON PREDICTION OF TREATMENT RESPONSE IN CERVICAL CANCERS

    Directory of Open Access Journals (Sweden)

    S. RUBINA

    2013-04-01

    Full Text Available Concurrent chemoradiotherapy (CCRT is the choice of treatment for locally advanced cervical cancers; however, tumors exhibit diverse response to treatment. Early prediction of tumor response leads to individualizing treatment regimen. Response evaluation criteria in solid tumors (RECIST, the current modality of tumor response assessment, is often subjective and carried out at the first visit after treatment, which is about four months. Hence, there is a need for better predictive tool for radioresponse. Optical spectroscopic techniques, sensitive to molecular alteration, are being pursued as potential diagnostic tools. Present pilot study aims to explore the fiber-optic-based Raman spectroscopy approach in prediction of tumor response to CCRT, before taking up extensive in vivo studies. Ex vivo Raman spectra were acquired from biopsies collected from 11 normal (148 spectra, 16 tumor (201 spectra and 13 complete response (151 CR spectra, one partial response (8 PR spectra and one nonresponder (8 NR spectra subjects. Data was analyzed using principal component linear discriminant analysis (PC-LDA followed by leave-one-out cross-validation (LOO-CV. Findings suggest that normal tissues can be efficiently classified from both pre- and post-treated tumor biopsies, while there is an overlap between pre- and post-CCRT tumor tissues. Spectra of CR, PR and NR tissues were subjected to principal component analysis (PCA and a tendency of classification was observed, corroborating previous studies. Thus, this study further supports the feasibility of Raman spectroscopy in prediction of tumor radioresponse and prospective noninvasive in vivo applications.

  15. Sum-Frequency-Generation-Based Laser Sidebands for Tunable Femtosecond Raman Spectroscopy in the Ultraviolet

    Directory of Open Access Journals (Sweden)

    Liangdong Zhu

    2015-04-01

    Full Text Available Femtosecond stimulated Raman spectroscopy (FSRS is an emerging molecular structural dynamics technique for functional materials characterization typically in the visible to near-IR range. To expand its applications we have developed a versatile FSRS setup in the ultraviolet region. We use the combination of a narrowband, ~400 nm Raman pump from a home-built second harmonic bandwidth compressor and a tunable broadband probe pulse from sum-frequency-generation-based cascaded four-wave mixing (SFG-CFWM laser sidebands in a thin BBO crystal. The ground state Raman spectrum of a laser dye Quinolon 390 in methanol that strongly absorbs at ~355 nm is systematically studied as a standard sample to provide previously unavailable spectroscopic characterization in the vibrational domain. Both the Stokes and anti-Stokes Raman spectra can be collected by selecting different orders of SFG-CFWM sidebands as the probe pulse. The stimulated Raman gain with the 402 nm Raman pump is >21 times larger than that with the 550 nm Raman pump when measured at the 1317 cm−1 peak for the aromatic ring deformation and ring-H rocking mode of the dye molecule, demonstrating that pre-resonance enhancement is effectively achieved in the unique UV-FSRS setup. This added tunability in the versatile and compact optical setup enables FSRS to better capture transient conformational snapshots of photosensitive molecules that absorb in the UV range.

  16. A Peltier cooling diamond anvil cell for low-temperature Raman spectroscopic measurements

    Science.gov (United States)

    Noguchi, Naoki; Okuchi, Takuo

    2016-12-01

    A new cooling system using Peltier modules is presented for a low-temperature diamond anvil cell instrument. This cooling system has many advantages: it is vibration-free, low-cost, and compact. It consists of double-stacked Peltier modules and heat sinks, where a cooled ethylene glycol-water mixture flows through a chiller. Current is applied to the Peltier modules by two programmable DC power supplies. Sample temperature can be controlled within the range 210-300 K with a precision of ±0.1 K via a Proportional-Integral-Differential (PID) control loop. A Raman spectroscopic study for the H2O ice VII-VIII transition is shown as an example of an application of the Peltier cooling diamond anvil cell system.

  17. FT-Raman spectroscopic analysis of pigments from an Augustinian friary.

    Science.gov (United States)

    Edwards, Howell G M; Newton, Emma M; O'Connor, Sonia; Evans, D

    2010-08-01

    The Raman spectroscopic analysis of several stone samples with applied red pigments obtained from an archaeological excavation of an Augustinian friary discovered during the construction of an extension to Hull Magistrates Court in 1994 has revealed a surprising diversity of composition. Cinnabar, red lead and haematite have all been identified alone or in admixture; the cinnabar is exceptional in that it has only been found heavily adulterated with red ochre and red lead, as the other two pigments are found alone. There are signatures of limewash putty, which has been applied to the stone substrate prior to the painting, which is characteristic of the Roman method of wall painting, and there are no traces of gypsum found in the specimens studied. This evidence indicates an early mediaeval method of stone decoration.

  18. Raman spectroscopic study of alunite occurrences in the Sapes porphyry-epithermal deposit, NE Greece

    Science.gov (United States)

    Papazotos, Panagiotis; Perraki, Maria; Voudouris, Panagiotis; Skliros, Vasilios

    2017-04-01

    The Sapes area, Northeastern Greece, represent a deeply eroded Oligocene volcanic edifice built up of post-collisional intermediate-to-acidic intrusives and their volcanic equivalents. The area hosts a telescoped porphyry-epithermal system and associated high-sulfidation epithermal Au-Ag-Cu-Bi-Te mineralization within advanced argillic alteration lithocaps (Voudouris, 2014). Alunite is a common mineralogical constituent among the advanced argillic alteration assemblages and it is a hydrated aluminium potassium sulfate mineral with a general formula KAl3(SO4)2(OH)6. The objective of this work is to study the alunites samples in the Sapes porphyry-epithermal deposit by means of Raman spectroscopy, as it has been shown to be a useful tool in studying the alunite structure, either natural or synthetic (Frost et al., 2006; Maubec et al., 2012). Raman spectra were excited employing a 532 nm laser at a resolution of 2 cm-1 in the range of 100-4000 cm-1. Raman spectra exhibit distinguished bands at 162 cm-1, attributed to translational mode of cations and or librational and translational modes of SO42-, at 235 cm-1 suggesting framework deformations including the SO42- entities as a whole or attributed to OH/O hydrogen bond stretching mode, a weak band at 385 cm-1 may corresponding to Al-OH stretching vibrations, a moderate band at 564 cm-1 assigned to Al-O and OH deformation modes, bands at 484 and 653 cm-1 respectively due to v2(SO42-) and v4(SO42-) bending modes, a very strong vibration at 1025 cm-1 that is ascribed to the v1 stretching vibration of the SO42- bands located at 1080 and 1186 cm-1 due to v3(SO42-) stretching modes and finally two bands at 3480 cm-1 and 3502 cm-1 that are assigned to the OH stretching vibrations (Breitinger et al., 1997; Frost et al., 2006; Maubec et al., 2012 and references therein). A Raman and FTIR spectroscopic future work will focus on the comparative study among the alunites occurrences in Greece (Sapes, Limnos, Lesvos and Milos), so

  19. Solvatochromism of 9,10-phenanthrenequinone: An electronic and resonance Raman spectroscopic study

    Science.gov (United States)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-01

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-π1*; S1 state) and the shorter (1π-π1*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm-1) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2ν symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling.

  20. Solvatochromism of 9,10-phenanthrenequinone: an electronic and resonance Raman spectroscopic study.

    Science.gov (United States)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-14

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-π(1)*; S1 state) and the shorter (1π-π(1)*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm(-1)) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2ν symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling.

  1. LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

    Science.gov (United States)

    Rosa, Cristiane B.; Habib, Fernando Antonio L.; de Araújo, Telma M.; dos Santos, Jean N.; Cangussu, Maria Cristina T.; Barbosa, Artur Felipe S.; de Castro, Isabele Cardoso V.; Soares, Luiz Guilherme P.; Pinheiro, Antonio L. B.

    2015-03-01

    A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020" stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

  2. INSTRUMENTS AND METHODS OF INVESTIGATION: New nonlinear laser effects in α-quartz: generation of a two-octave Stokes and anti-Stokes comb and cascaded lasing in the spectral range of the second and third harmonics

    Science.gov (United States)

    Kaminskii, A. A.; Bohatý, L.; Becker, P.; Eichler, H. J.; Rhee, H.

    2008-09-01

    Crystals that are simultaneously χ(2)- and χ(3)-active offer a wide range of possibilities for the generation of new coherent wavelengths of light. Frequency conversion processes such as stimulated Raman scattering, second and third harmonic generation, or parametric sum and difference frequency mixing can be combined effectively in the same noncentrosymmetric crystal in cascaded χ(3) χ(2) lasing processes. We present several new manifestations of these effects under picosecond laser excitation in α-quartz (SiO2), the oldest nonlinear-laser crystal. Among them are 45 Stokes and anti-Stokes wavelength comb generation of more than two octaves (from 0.3692 μm to 1.5142 μm) and self-conversion of Raman-generation frequencies into the wavelength region of the second and third harmonics of one-micron pumping via many-step cascaded χ(3) χ(2) processes.

  3. Raman Spectroscopy and Microscopy of Individual Cells andCellular Components

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J; Fore, S; Wachsmann-Hogiu, S; Huser, T

    2008-05-15

    Raman spectroscopy provides the unique opportunity to non-destructively analyze chemical concentrations on the submicron length scale in individual cells without the need for optical labels. This enables the rapid assessment of cellular biochemistry inside living cells, and it allows for their continuous analysis to determine cellular response to external events. Here, we review recent developments in the analysis of single cells, subcellular compartments, and chemical imaging based on Raman spectroscopic techniques. Spontaneous Raman spectroscopy provides for the full spectral assessment of cellular biochemistry, while coherent Raman techniques, such as coherent anti-Stokes Raman scattering is primarily used as an imaging tool comparable to confocal fluorescence microscopy. These techniques are complemented by surface-enhanced Raman spectroscopy, which provides higher sensitivity and local specificity, and also extends the techniques to chemical indicators, i.e. pH sensing. We review the strengths and weaknesses of each technique, demonstrate some of their applications and discuss their potential for future research in cell biology and biomedicine.

  4. Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasma interaction

    Science.gov (United States)

    Feng, Q. S.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Wang, Q.; Zhang, H. C.; Cao, L. H.; He, X. T.

    2017-07-01

    Anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascades have been researched using the Vlasov-Maxwell simulation. In high-intensity laser-plasma interactions, stimulated anti-Stokes Brillouin scattering (SABS) will occur after second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. In the early phase of SBS evolution, only first stage SBS appears and total SBS reflectivity comes from first stage SBS. However, when high-stage SBS and SABS occur, SBS reflectivity will display burst behavior and the total reflectivity comes from the SBS cascade and SABS superimposition. The SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, SBS rescattering including SABS is an important saturation mechanism of SBS and should be taken into account in high-intensity laser-plasma interaction.

  5. Resonance Raman and EPR spectroscopic studies on heme-heme oxygenase complexes.

    Science.gov (United States)

    Sun, J; Wilks, A; Ortiz de Montellano, P R; Loehr, T M

    1993-12-28

    The binding of ferrous and ferric hemes and manganese(II)- and manganese(III)-substituted hemes to heme oxygenase has been investigated by optical absorption, resonance Raman, and EPR spectroscopy. The results are consistent with the presence of a six-coordinate heme moiety ligated to an essential histidine ligand and a water molecule. The latter ionizes with a pKa approximately 8.0 to give a mixture of high-spin and low-spin six-coordinate hydroxo adducts. Addition of excess cyanide converts the heme to a hexacoordinate low-spin species. The resonance Raman spectrum of the ferrous heme-heme oxygenase complex and that of the Mn(II)protoporphyrin-heme oxygenase complex shows bands at 216 and 212 cm-1, respectively, that are assigned to the metal-histidine stretching mode. The EPR spectrum of the oxidized heme-heme oxygenase complex has a strongly axial signal with g parallel of approximately 6 and g perpendicular approximately 2. 14NO and 15NO adducts of ferrous heme-heme oxygenase exhibit EPR hyperfine splittings of approximately 20 and approximately 25 Gauss, respectively. In addition, both nitrosyl complexes show additional superhyperfine splittings of approximately 7 Gauss from spin-spin interaction with the proximal histidine nitrogen. The heme environment in the heme-heme oxygenase enzyme-substrate complex has spectroscopic properties similar to those of the heme in myoglobin. Hence, there is neither a strongly electron-donating fifth (proximal) ligand nor an electron-withdrawing network on the distal side of the heme moiety comparable to that for cytochromes P-450 and peroxidases. This observation has profound implications about the nature of the oxygen-activating process in the heme-->biliverdin reaction that are discussed in this paper.

  6. Flow-through microdispenser for interfacing micro-HPLC to Raman and mid-IR spectroscopic detection.

    Science.gov (United States)

    Surowiec, Izabella; Baena, Josefa R; Frank, Johannes; Laurell, Thomas; Nilsson, Johan; Trojanowicz, Marek; Lendl, Bernhard

    2005-07-08

    A flow-through microdispenser has been coupled to a micro HPLC separation system and used as a solvent elimination interface for Fourier transform infrared (FTIR) and Raman spectroscopic detection of the separated compounds. Using the microdispenser picoliter sized droplets can be generated and deposited on an appropriate target placed on a computerized x, y-stage. Evaporation of volatile solvent and buffer is rapid and allows analysis of the obtained dry deposits by various techniques. Due to the destruction free character of Raman and FTIR spectroscopy they can be applied sequentially to interrogate the same deposit. In the reported application five phenolic acids typically present in wine have been separated on a C-18 column technique using a mixture of water, methanol and acetic acid as mobile phase. For spectrum acquisition infrared and Raman microscopes have been used. The spectra recorded from the dried deposits of the separated compounds agreed well with the reference spectra of corresponding components.

  7. Development, validation and comparison of near infrared and Raman spectroscopic methods for fast characterization of tablets with amlodipine and valsartan.

    Science.gov (United States)

    Casian, Tibor; Reznek, Andra; Vonica-Gligor, Andreea Loredana; Van Renterghem, Jeroen; De Beer, Thomas; Tomuță, Ioan

    2017-05-15

    The objective of this study was to develop, validate and compare NIR and Raman spectroscopic methods for fast characterization in terms of API content and tensile strength of fixed-dose combination tablets containing amlodipine and valsartan. For the APIs assay NIR-transmittance and Raman-reflectance methods were considered, whereas for the tensile strength assay Raman spectra were recorded in reflectance configuration and NIR spectra were recorded in both reflectance and transmittance. Multivariate calibration models (PLS) were built by applying different pre-processing methods (SNV, MSC, SD+SNV) on certain spectral regions. Correlating pre-processed spectral data with tablet properties resulted in highly predictive models except in the case of NIR-transmittance spectra for tensile strength estimation. The best models selected by cross-validation were further validated on independent samples in terms of linearity, trueness, accuracy and precision. Using Bland and Altman analysis the analytical performance of the NIR and Raman methods were compared, demonstrating their similarity considering the investigated applications. The two spectroscopic methods can be used in association to confirm each others results for at-line characterization of the pharmaceutical product. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Raman spectroscopic investigation of the chemopreventive response of naringenin and its nanoparticles in DMBA-induced oral carcinogenesis

    Science.gov (United States)

    Krishnakumar, N.; Sulfikkarali, N. K.; Manoharan, S.; Venkatachalam, P.

    2013-11-01

    Raman spectroscopy is a vibrational spectroscopic technique that can be used to optically probe the biomolecular changes associated with tumor progression. The aim of the present study is to investigate the biomolecular changes in chemopreventive response of prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) during 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis by Fourier Transform Raman (FT-Raman) spectroscopy. Oral squamous cell carcinoma (OSCC) was developed in the buccal pouch of golden Syrian hamsters by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Raman spectra differed significantly between the control and tumor tissues, with tumors showing higher percentage signals for nucleic acids, phenylalanine and tryptophan and a lower in the percentage of phospholipids. Moreover, oral administration of free NAR and NARNPs significantly increased phospholipids and decreased the levels of tryptophan, phenylalanine and nucleic acid contents. On a comparative basis, NARNPs was found to have a more potent antitumor effect than free NAR in completely preventing the formation of squamous cell carcinoma and in improving the biochemical status to a normal range in DMBA-induced oral carcinogenesis. The present study further suggest that Raman spectroscopy could be a valuable tool for rapid and sensitive detection of specific biomolecular changes in response to chemopreventive agents.

  9. Raman spectroscopic analyses of preserved historical specimens of human hair attributed to Robert Stephenson and Sir Isaac Newton.

    Science.gov (United States)

    Edwards, Howell G M; Hassan, Nik F N; Wilson, Andrew S

    2004-10-01

    The Raman spectra of two historical specimens of human hair attributed to the engineer Robert Stephenson and scientist Sir Isaac Newton, preserved in private collections are reported. Comparisons are made with the Raman spectra of modern hair specimens and with hair from archaeological excavations. The hair spectra collected with a laser excitation of 785 nm are of a better quality than those collected using 1064 nm. The historical hair specimens are remarkably well-defined spectroscopically in terms of the amide I vibrational mode and the [small nu](SS), ascribed to a predominantly gauche-gauche-gauche CSSC conformation. The contrast with degraded hair specimens recovered from archaeological excavations is striking. The presence of a weak feature near 2590 cm(-1) in the hair samples attributed to a [small nu](SH) vibration could be indicative of a reduction process operative on the CSSC cystine keratotic linkages and a possible origin of this is bacterial biodegradation identified histologically. This study demonstrates the molecular information available from non-destructive Raman spectroscopic analysis from single hair shafts or small bundles of fibres which complements information available from histological and destructive analytical techniques for rare biological specimens subjected to conservation or curation procedures in museums or private collections.

  10. Investigation of the Brill transition in nylon 6,6 by Raman, THz-Raman, and two-dimensional correlation spectroscopy

    Science.gov (United States)

    Bertoldo Menezes, D.; Reyer, A.; Musso, M.

    2018-02-01

    The Brill transition is a phase transition process in polyamides related with structural changes between the hydrogen bonds of the lateral functional groups (Cdbnd O) and (Nsbnd H). In this study, we have used the potential of Raman spectroscopy for exploring this phase transition in polyamide 6,6 (nylon 6,6), due to the sensitivity of this spectroscopic technique to small intermolecular changes affecting vibrational properties of relevant functional groups. During a step by step heating and cooling process of the sample we collected Raman spectra allowing us from two-dimensional Raman correlation spectroscopy to identify which spectral regions suffered the largest influence during the Brill transition, and from Terahertz Stokes and anti-Stokes Raman spectroscopy to obtain complementary information, e.g. on the temperature of the sample. This allowed us to grasp signatures of the Brill transition from peak parameters of vibrational modes associated with (Csbnd C) skeletal stretches and (CNH) bending, and to verify the Brill transition temperature at around 160 °C, as well as the reversibility of this phase transition.

  11. The biocompatibility of carbon hydroxyapatite/β-glucan composite for bone tissue engineering studied with Raman and FTIR spectroscopic imaging.

    Science.gov (United States)

    Sroka-Bartnicka, Anna; Kimber, James A; Borkowski, Leszek; Pawlowska, Marta; Polkowska, Izabela; Kalisz, Grzegorz; Belcarz, Anna; Jozwiak, Krzysztof; Ginalska, Grazyna; Kazarian, Sergei G

    2015-10-01

    The spectroscopic approaches of FTIR imaging and Raman mapping were applied to the characterisation of a new carbon hydroxyapatite/β-glucan composite developed for bone tissue engineering. The composite is an artificial bone material with an apatite-forming ability for the bone repair process. Rabbit bone samples were tested with an implanted bioactive material for a period of several months. Using spectroscopic and chemometric methods, we were able to determine the presence of amides and phosphates and the distribution of lipid-rich domains in the bone tissue, providing an assessment of the composite's bioactivity. Samples were also imaged in transmission using an infrared microscope combined with a focal plane array detector. CaF2 lenses were also used on the infrared microscope to improve spectral quality by reducing scattering artefacts, improving chemometric analysis. The presence of collagen and lipids at the bone/composite interface confirmed biocompatibility and demonstrate the suitability of FTIR microscopic imaging with lenses in studying these samples. It confirmed that the composite is a very good background for collagen growth and increases collagen maturity with the time of the bone growth process. The results indicate the bioactive and biocompatible properties of this composite and demonstrate how Raman and FTIR spectroscopic imaging have been used as an effective tool for tissue characterisation.

  12. Fourier transform Raman spectroscopic characterisation of cells of the plant-associated soil bacterium Azospirillum brasilense Sp7

    Science.gov (United States)

    Kamnev, A. A.; Tarantilis, P. A.; Antonyuk, L. P.; Bespalova, L. A.; Polissiou, M. G.; Colina, M.; Gardiner, P. H. E.; Ignatov, V. V.

    2001-05-01

    Structural and compositional features of bacterial cell samples and of lipopolysaccharide-protein complex isolated from the cell surface of the plant-growth-promoting rhizobacterium Azospirillum brasilense (wild-type strain Sp7) were characterised using Fourier transform (FT) Raman spectroscopy. The structural spectroscopic information obtained is analysed and considered together with analytical data on the content of metal cations (Co 2+, Cu 2+ and Zn 2+) in the bacterial cells grown in a standard medium as well as in the presence of each of the cations (0.2 mM). The latter, being taken up by bacterial cells from the culture medium in significant amounts, were shown to induce certain metabolic changes in the bacterium revealed in FT-Raman spectra, which is discussed from the viewpoint of bacterial response to environmental stresses.

  13. Raman and Terahertz Spectroscopic Investigation of Cocrystal Formation Involving Antibiotic Nitrofurantoin Drug and Coformer 4-aminobenzoic Acid

    Directory of Open Access Journals (Sweden)

    Yong Du

    2016-12-01

    Full Text Available Cocrystallization could improve most physicochemical properties of specific active pharmaceutical ingredients, which has great potential in pharmaceutical development. In this study, the cocrystal of nitrofurantoin and 4-aminobenzoic acid was prepared with solid-state (solvent-free or green-chemistry grinding approach, and the above cocrystal has been characterized by Raman and terahertz vibrational spectroscopic techniques. Spectral results show that the vibrational modes of the cocrystal within the whole spectral region are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman spectra. These results offer us unique means for characterizing the cocrystal conformation from the molecule-level, and provides us with rich information about the reaction dynamic of cocrystal formation within pharmaceutical fields.

  14. Book Review: Reiner Salzer and Heinz W. Siesler (Eds.): Infrared and Raman spectroscopic imaging, 2nd ed

    International Nuclear Information System (INIS)

    Moore, David Steven

    2015-01-01

    This second edition of 'Infrared and Raman Spectroscopic Imaging' propels practitioners in that wide-ranging field, as well as other readers, to the current state of the art in a well-produced and full-color, completely revised and updated, volume. This new edition chronicles the expanded application of vibrational spectroscopic imaging from yesterday's time-consuming point-by-point buildup of a hyperspectral image cube, through the improvements afforded by the addition of focal plane arrays and line scan imaging, to methods applicable beyond the diffraction limit, instructs the reader on the improved instrumentation and image and data analysis methods, and expounds on their application to fundamental biomedical knowledge, food and agricultural surveys, materials science, process and quality control, and many others

  15. Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasmas interaction

    Science.gov (United States)

    Feng, Qingsong; Zheng, Chunyang; Liu, Zhanjun; Xiao, Chengzhuo; Wang, Qing; Cao, Lihua; He, Xiantu

    2017-10-01

    The anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascade have been researched by the Vlasov-Maxwell simulation. In the high-intensity laser-plasmas interaction, the stimulated anti-Stokes Brillouin scattering (SABS) will occur after the second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. In the early time of SBS evolution, only the first stage SBS appears, and the total SBS reflectivity comes from the first stage SBS. However, when the high-stage SBS and SABS occur, the SBS reflectivity will appear a burst behavior, and the total reflectivity comes from the SBS cascade and SABS superimposition. The SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, the SBS rescattering including the SABS is an important saturation mechanism of SBS, and should be taken into account in the high-intensity laser-plasmas interaction. This research was supported by the National Natural Science Foundation of China (Grant Nos. 11375032, 11575035, 11475030 and 11435011), National Basic Research Program of China (Grant No. 2013CB834101) and Science Challenge Project, No. TZ2016005.

  16. Expanding Anti-Stokes Shifting in Triplet-Triplet Annihilation Upconversion for In Vivo Anticancer Prodrug Activation.

    Science.gov (United States)

    Huang, Ling; Zhao, Yang; Zhang, He; Huang, Kai; Yang, Jinyi; Han, Gang

    2017-11-13

    A strategy to expand anti-Stokes shifting from the far-red to deep-blue region in metal-free triplet-triplet annihilation upconversion (TTA-UC) is presented. The method is demonstrated by in vivo titration of the photorelease of an anticancer prodrug. This new TTA system has robust brightness and the longest anti-Stokes shift of any reported TTA system. TTA core-shell-structured prodrug delivery capsules that benefit from these properties were developed; they can operate with low-power density far-red light-emitting diode light. These capsules contain mesoporous silica nanoparticles preloaded with TTA molecules as the core, and amphiphilic polymers encapsulating anticancer prodrug molecules as the shell. When stimulated by far-red light, the intense TTA upconversion blue emission in the system activates the anticancer prodrug molecules and shows effective tumor growth inhibition in vivo. This work paves the way to new organic TTA upconversion techniques that are applicable to in vivo photocontrollable drug release and other biophotonic applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Infrared and Raman spectroscopic study of ion pairing of strontium(II ...

    African Journals Online (AJOL)

    ABSTRACT. Infrared and Raman spectroscopy techniques have been used to study the ionic interactions of strontium(II) and barium(II) with thiocyanate ion in liquid ammonia. A number of bands were observed in both ν(CN) and ν(CS) regions of infrared and Raman spectra and these were assigned to 1:1 contact ion pair, ...

  18. Using Raman spectroscopic imaging for non-destructive analysis of filler distribution in chalk filled polypropylene

    DEFF Research Database (Denmark)

    Boros, Evelin; Porse, Peter Bak; Nielsen, Inga

    2016-01-01

    A feasibility study on using Raman spectral imaging for visualization and analysis of filler distribution in chalk filled poly-propylene samples has been carried out. The spectral images were acquired using a Raman spectrometer with 785 nm light source.Eight injection-molded samples with concentr...

  19. A Simple Surface-Enhanced Raman Spectroscopic Method for on-Site Screening of Tetracycline Residue in Whole Milk

    Directory of Open Access Journals (Sweden)

    Sagar Dhakal

    2018-02-01

    Full Text Available Therapeutic and subtherapeutic use of veterinary drugs has increased the risk of residue contamination in animal food products. Antibiotics such as tetracycline are used for mastitis treatment of lactating cows. Milk expressed from treated cows before the withdrawal period has elapsed may contain tetracycline residue. This study developed a simple surface-enhanced Raman spectroscopic (SERS method for on-site screening of tetracycline residue in milk and water. Six batches of silver colloid nanoparticles were prepared for surface enhancement measurement. Milk-tetracycline and water-tetracycline solutions were prepared at seven concentration levels (1000, 500, 100, 10, 1, 0.1, and 0.01 ppm and spiked with silver colloid nanoparticles. A 785 nm Raman spectroscopic system was used for spectral measurement. Tetracycline vibrational modes were observed at 1285, 1317 and 1632 cm−1 in water-tetracycline solutions and 1322 and 1621 cm−1 (shifted from 1317 and 1632 cm−1, respectively in milk-tetracycline solutions. Tetracycline residue concentration as low as 0.01 ppm was detected in both the solutions. The peak intensities at 1285 and 1322 cm−1 were used to estimate the tetracycline concentrations in water and milk with correlation coefficients of 0.92 for water and 0.88 for milk. Results indicate that this SERS method is a potential tool that can be used on-site at field production for qualitative and quantitative detection of tetracycline residues.

  20. A microfluidic surface enhanced Raman spectroscopic biosensor using aptamer functionalized nanopillars

    DEFF Research Database (Denmark)

    Yang, J.; Palla, M.; Bosco, F. G.

    2013-01-01

    This paper presents a microchip incorporating an aptamer-functionalized nanopillar substrate, enabling the specific detection of low-abundance biomolecules using surface enhanced Raman spectroscopy (SERS). In a temperature controlled microchamber, aptamers immobilized on the nanostructure surface...

  1. Raman spectroscopic and mass spectrometric investigations of the hydrogen isotopes and isotopically labelled methanes

    International Nuclear Information System (INIS)

    Engelmann, U.

    1992-12-01

    Suitable analytical methods need to be developed and tested for process control and reliable tritium accountability within the fuel cycle of a fusion reactor. The analysis of all hydrogen isotopes and isotopically labelled methanes were taken as an example to examine the laser Raman spectroscopy combined with mass spectrometry using an Omegatron. The Omegatron is suitable for the analysis of all hydrogen isotopes and the stable helium isotopes. The limits of the applicability of this mass spectrometer were shown by the analysis of mixtures of deuterated methanes. The Omegatron was also used for experiments of the radiochemical 'Wilzbach' exchange reaction between tritium and methanes. A laser Raman spectrometer for the analysis of gaseous mixtures containing tritium was designed and build using the single components. A tritium compatible, metal sealed Raman cell with windows of high optical quality and additional measures to minimize stray light was successfully employed for the first time. The Raman spectra of the hydrogen isotopes were measured in the pure rotation and in the rotation vibration branches and used for calibration. The deuterated methanes (CH x D 4-x ) were investigated by Raman spectroscopy, the measured wavenumbers assigned to the corresponding normal vibrations and the wavenumbers of the rotational fine structure summarized in tables. The normal vibrations of the tritiated methanes (CH x T 4-x , CD x T 4-x ) produced via the 'Wilzbach' reaction were determined and assigned. The normal vibrations of the CD x T 4-x molecules were measured by Raman spectroscopy for the first time. (orig.)

  2. A Raman spectroscopic study of arsenite and thioarsenite species in aqueous solution at 25°C

    Directory of Open Access Journals (Sweden)

    Janecky David R

    2002-02-01

    Full Text Available The Raman spectra of thioarsenite and arsenite species in aqueous solution were obtained at room temperature. Solutions at constant ΣAs + ΣS of 0.1 and 0.5 mol kg-1 were prepared with various ΣS/ΣAs ratios (0.1–9.0 and pH values (~7–13.2. Our data suggest that the speciation of As under the conditions investigated is more complicated than previously thought. The Raman measurements offer evidence for at least six separate S-bearing As species whose principal bands are centered near 365, 385, 390, 400, 415 and 420 cm-1. The data suggest that at least two different species may give rise to bands at 385 cm-1, bringing the probable minimum number of species to seven. Several additional species are possible but could not be resolved definitively. In general, the relative proportions of these species are dependent on total As concentration, ΣS/ΣAs ratio and pH. At very low ΣS/ΣAs ratios we also observe Raman bands attributable to the dissociation products of H3AsO3(aq. Although we were unable to assign precise stoichiometries for the various thioarsenite species, we were able to map out general pH and ΣS/ΣAs conditions under which the various thioarsenite and arsenite species are predominant. This study provides a basis for more detailed Raman spectroscopic and other types of investigations of the nature of thioarsenite species.

  3. Development of an in-line Raman spectroscopic method for continuous API quantification during twin-screw wet granulation.

    Science.gov (United States)

    Harting, Julia; Kleinebudde, Peter

    2018-04-01

    Raman spectroscopy was evaluated as a process analytical technology (PAT) tool for continuous API quantification during twin-screw wet granulation. Therefore, a Raman probe was implemented in front of the granulator barrel. This setup enabled the collection of Raman spectra upon a constant granule flow. To develop an in-line PLS calibration model, eight binary mixtures of the API and lactose monohydrate with API contents between 5 and 50% were pre-blended and granulated in a twin-screw granulator with a screw speed of 150 rpm and a powder feed rate of 40 g/min. Water was used as a granulation liquid with different liquid to solid ratios depending on the API content. Ibuprofen and diclofenac sodium were chosen as model drugs and separated PLS models were built for each API. The predictive performance of the developed PLS models was determined by granulating and monitoring new test samples containing different API concentrations. This evaluation showed that the models were able to predict the API concentration with an RMSEP of 0.59% for ibuprofen and 1.5% for diclofenac sodium. In a second part, the developed in-line Raman spectroscopic method was used to determine the API concentration during a split feeding process. Therefore, the API and lactose monohydrate were added by two independently adjustable feeders into the twin-screw granulator barrel. The in-line spectroscopy analysis which was verified by UV-analysis indicated that the mixing ability of the twin-screw granulator was good for the used settings and all adjusted API concentrations. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Spectroscopic analysis (FTIR, Raman) of water in mafic and intermediate glasses and glass inclusions

    International Nuclear Information System (INIS)

    Mercier, Maxime; Di Muro, Andrea; Metrich, Nicole; Belhadj, Olfa; Giordano, Daniele; Mandeville, Charles W.

    2010-01-01

    Micro-Raman spectroscopy, even though a very promising technique, is not still routinely applied to analyse H 2 O in silicate glasses. The accuracy of Raman water determinations critically depends on the capability to predict and take into account both the matrix effects (bulk glass composition) and the analytical conditions on band intensities. On the other hand, micro-Fourier transform infrared spectroscopy is commonly used to measure the hydrous absorbing species (e.g., hydroxyl OH and molecular H 2 O) in natural glasses, but requires critical assumptions for the study of crystal-hosted glasses. Here, we quantify for the first time the matrix effect of Raman external calibration procedures for the quantification of the total H 2 O content (H 2 O(T) = OH - + H 2 O m ) in natural silicate glasses. The procedures are based on the calibration of either the absolute (external calibration) or scaled (parameterization) intensity of the 3550 cm -1 band. A total of 67 mafic (basanite, basalt) and intermediate (andesite) glasses hosted in olivines, having between 0.2 and 4.8 wt% of H 2 O, was analysed. Our new dataset demonstrates, for given water content, the height (intensity) of Raman H 2 OT band depends on glass density, reflectance and water environment. Hence this matrix effect must be considered in the quantification of H 2 O by Raman spectroscopy irrespective of the procedure, whereas the parameterization mainly helps to predict and verify the self-consistency of the Raman results. In addition, to validate the capability of the micro-Raman to accurately determine the H 2 O content of multicomponent aluminosilicate glasses, a subset of 23 glasses was analysed by both micro-Raman and micro-FTIR spectroscopy using the band at 3550 cm -1 . We provide new FTIR absorptivity coefficients ε 3550 ) for basalt (62.80 ± 0.8 L mol -1 cm -1 ) and basanite (43.96 ± 0.6 L mol -1 cm -1 ). These values, together with an exhaustive review of literature data, confirm the non

  5. Raman spectroscopic study of acute oxidative stress induced changes in mice skeletal muscles

    Science.gov (United States)

    Sriramoju, Vidyasagar; Alimova, Alexandra; Chakraverty, Rahul; Katz, A.; Gayen, S. K.; Larsson, L.; Savage, H. E.; Alfano, R. R.

    2008-02-01

    The oxidative stress due to free radicals is implicated in the pathogenesis of tissue damage in diseases such as muscular dystrophy, Alzheimer dementia, diabetes mellitus, and mitochrondrial myopathies. In this study, the acute oxidative stress induced changes in nicotinamide adenine dinucleotides in mouse skeletal muscles are studied in vitro using Raman spectroscopy. Mammalian skeletal muscles are rich in nicotinamide adenine dinucleotides in both reduced (NADH) and oxidized (NAD) states, as they are sites of aerobic and anaerobic respiration. The relative levels of NAD and NADH are altered in certain physiological and pathological conditions of skeletal muscles. In this study, near infrared Raman spectroscopy is used to identify the molecular fingerprints of NAD and NADH in five-week-old mice biceps femoris muscles. A Raman vibrational mode of NADH is identified in fresh skeletal muscle samples suspended in buffered normal saline. In the same samples, when treated with 1% H IIO II for 5 minutes and 15 minutes, the Raman spectrum shows molecular fingerprints specific to NAD and the disappearance of NADH vibrational bands. The NAD bands after 15 minutes were more intense than after 5 minutes. Since NADH fluoresces and NAD does not, fluorescence spectroscopy is used to confirm the results of the Raman measurements. Fluorescence spectra exhibit an emission peak at 460 nm, corresponding to NADH emission wavelength in fresh muscle samples; while the H IIO II treated muscle samples do not exhibit NADH fluorescence. Raman spectroscopy may be used to develop a minimally invasive, in vivo optical biopsy method to measure the relative NAD and NADH levels in muscle tissues. This may help to detect diseases of muscle, including mitochondrial myopathies and muscular dystrophies.

  6. Native alunogen: A Raman spectroscopic study of a well-described specimen

    Science.gov (United States)

    Košek, Filip; Culka, Adam; Žáček, Vladimír; Laufek, František; Škoda, Radek; Jehlička, Jan

    2018-04-01

    Alunogen (Al2(SO4)3 · 17H2O) is a common secondary mineral in the terrestrial environment (acid mine drainage, volcanic or coal-fire fumaroles), and is also formed through the acidic weathering of aluminosilicates. Moreover, alunogen has been suggested as a part of the Al-bearing deposits on Mars. The identification of alunogen in secondary sulfate mixtures by Raman spectroscopy strictly depends on good knowledge of alunogen spectral features and band positions. However, comprehensive Raman data of alunogen of natural origin are lacking. This study reports on Raman spectra obtained from two natural specimens originating from a burning coal dump at the Schoeller mine, Kladno, Czech Republic, along with the additional characterizations by infrared spectroscopy, X-ray diffraction, and electron microprobe. For comparison purposes, a Raman spectrum of a synthetic analogue was also obtained. The studied specimens have (Al1.99Fe3+0.01)2 (SO4)3·17H2O as their calculated empirical formula, and the structural parameters correspond to the previously reported data for alunogen. Both natural specimens and the synthetic analogue showed uniform Raman spectra with no extensive band splitting in the sulfate vibrational regions. The most intensive Raman band associated with the symmetric stretching vibration of the SO4 tetrahedra (ν1) is located at 992 cm-1. A multicomponent band was observable in the characteristic region for OH-related vibrations. A small variation in the spectral intensity of the hydroxyl bands suggests that the studied specimens could possibly be slightly dehydrated.

  7. Molten sodium vanadate attack of yttria-stabilized zirconia: A raman spectroscopic investigation

    International Nuclear Information System (INIS)

    Hamilton, J.C.; Nayelberg, A.S.

    1983-01-01

    The authors used Raman spectroscopy to study the attack by molten Na 2 V 2 O 6 of ceramics used as thermal barrier coatings in combustion systems. These ZrO 2 -Y 2 O 3 ceramics were transformed from cubic/tetragonal to monoclinic structures during 9-hr salt immersion at 900 0 C, because of leaching of yttria from the ceramic in the near surface region (approx. =50 um). Raman spectroscopy is a powerful tool to study this behavior, since it can simultaneously probe both salt chemistry and ceramic structure

  8. Raman Spectroscopic Study of the Vapour Phase of 1-Methylimidazolium Ethanoate, a Protic Ionic Liquid

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Canongia Lopes, Jose N.; Ferreira, Rui

    2010-01-01

    The gas phase over the ionic liquid 1-methylimidazolium ethanoate, [Hmim][O2CCH3], was studied by means of Raman spectroscopy. Raman spectra are presented, the species in the gas phase are identified, and their bands are assigned. The results are interpreted using ab initio quantum mechanical...... calculations that also predict vibrational spectra. The obtained data reinforce a previous interpretation, based on FT-ICR mass spectrometric data, that the vapor phase over [Hmim][O2CCH3] consists predominantly of two neutral molecules, monomeric ethanoic acid and 1-methylimidazole....

  9. Raman spectroscopic evaluation of meat batter structural changes induced by thermal treatment and salt addition.

    Science.gov (United States)

    Herrero, A M; Carmona, P; López-López, I; Jiménez-Colmenero, F

    2008-08-27

    Raman spectroscopy, texture, proximate composition, and water binding analysis were carried out to evaluate the effect of thermal treatment and/or salt addition to meat batter. For this purpose, different meat batters were elaborated: control meat batter (no salt) and meat batters with low (1.0%) and high (2.5%) NaCl content with and without thermal treatment (70 degrees C/30 min). Increase (P batter. Raman spectroscopy analysis revealed a significant (P batter. In this way, a significant correlation was found between beta-sheets, salt content, hardness, and chewiness in heated samples.

  10. The spectroscopic (FT-IR, FT-Raman, dispersive Raman and NMR) study of ethyl-6-chloronicotinate molecule by combined density functional theory.

    Science.gov (United States)

    Karabacak, Mehmet; Calisir, Zuhre; Kurt, Mustafa; Kose, Etem; Atac, Ahmet

    2016-01-15

    In this study, ethyl-6-chloronicotinate (E-6-ClN) molecule is recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1) (FT-IR, FT-Raman and dispersive Raman, respectively) in the solid phase. ((1))H and ((13))C nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The structural and spectroscopic data of the molecule are obtained for two possible isomers (S1 and S2) from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule is fully optimized, vibrational spectra are calculated and fundamental vibrations are assigned on the basis of the potential energy distribution (PED) of the vibrational modes. ((1))H and ((13))C NMR chemical shifts are calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strengths, wavelengths, HOMO and LUMO energies, are performed by time-dependent density functional theory (TD-DFT). Total and partial density of state and overlap population density of state diagrams analysis are presented for E-6-ClN molecule. Furthermore, frontier molecular orbitals (FMO), molecular electrostatic potential, and thermodynamic features are performed. In addition to these, reduced density gradient of the molecule is performed and discussed. As a conclusion, the calculated results are compared with the experimental spectra of the title compound. The results of the calculations are applied to simulate the vibrational spectra of the molecule, which show excellent agreement with the observed ones. The theoretical and tentative results will give us a detailed description of the structural and physicochemical properties of the molecule. Natural bond orbital analysis is done to have more information stability of the molecule arising from charge delocalization, and to reveal the information regarding charge transfer within the molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. raman

    Indian Academy of Sciences (India)

    also had the devoted and loyal assistance of Asutosh Dey, known to everyone in the Association as Ashu Babu. Raman soon ...... Even after reaching the hotel, the stream of photographers and news- paper reporters continued to show us their ...... My affection, loyalty and respect for him were something extraordinary and I ...

  12. A micro-Raman spectroscopic investigation of leukemic U-937 cells in aged cultures

    Science.gov (United States)

    Fazio, Enza; Trusso, Sebastiano; Franco, Domenico; Nicolò, Marco Sebastiano; Allegra, Alessandro; Neri, Fortunato; Musolino, Caterina; Guglielmino, Salvatore P. P.

    2016-04-01

    Recently it has been shown that micro-Raman spectroscopy combined with multivariate analysis is able to discriminate among different types of tissues and tumoral cells by the detection of significant alterations and/or reorganizations of complex biological molecules, such as nucleic acids, lipids and proteins. Moreover, its use, being in principle a non-invasive technique, appears an interesting clinical tool for the evaluation of the therapeutical effects and of the disease progression. In this work we analyzed molecular changes in aged cultures of leukemia model U937 cells with respect to fresh cultures of the same cell line. In fact, structural variations of individual neoplastic cells on aging may lead to a heterogeneous data set, therefore falsifying confidence intervals, increasing error levels of analysis and consequently limiting the use of Raman spectroscopy analysis. We found that the observed morphological changes of U937 cells corresponded to well defined modifications of the Raman contributions in selected spectral regions, where markers of specific functional groups, useful to characterize the cell state, are present. A detailed subcellular analysis showed a change in cellular organization as a function of time, and correlated to a significant increase of apoptosis levels. Besides the aforementioned study, Raman spectra were used as input for principal component analysis (PCA) in order to detect and classify spectral changes among U937 cells.

  13. Raman spectroscopic study on sodium hyaluronate: an effect of proton and gamma irradiation

    Czech Academy of Sciences Publication Activity Database

    Synytsya, A.; Alexa, P.; Wagner, Richard; Davídková, Marie; Volka, K.

    2011-01-01

    Roč. 42, č. 3 (2011), s. 544-550 ISSN 0377-0486 Institutional research plan: CEZ:AV0Z10480505 Keywords : sodium hyaluronate * proton irradiation * gamma irradiation * Raman spectroscopy Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.087, year: 2011 http://onlinelibrary.wiley.com/doi/10.1002/jrs.2724/full

  14. Raman spectroscopic analysis of Lactobacillus rhamnosus GG in response to dehydration reveals DNA conformation changes.

    Science.gov (United States)

    Myintzu Hlaing, Mya; Wood, Bayden; McNaughton, Don; Ying, DanYan; Augustin, Mary Ann

    2017-04-01

    Dehydration of bacterial cells elicits cellular stress responses in bacteria. Microencapsulation has been used to protect cells against the environmental stress. In this study, Confocal Raman Spectroscopy was used to examine DNA changes in the chemical composition of non-encapsulated and microencapsulated Lactobacillus rhamnosus GG and the reversibility of these changes upon freeze drying and rehydration. The viability of cells upon freeze drying was also enumerated using culture methods and membrane integrity was measured using BacLight Live/Dead staining. Raman analyses show changes in the spectral features associated with various biochemical compounds, which are interpreted as the result of detrimental freeze drying effects on the bacterial cells. Specifically, analyses based on Principal Components Analysis (PCA) of Raman spectra, confirm that microencapsulation protects cells from environmental stress. The results also reveal a B- to A-like DNA conformation change in dormant cells that provided insights into the extent of reversibility of this transition upon rehydration. The extent of this reversibility is less in non-encapsulated than in microencapsulated cells. These findings indicate the potential application of Raman spectroscopy in rapid sensing of microbial dehydration stress responses. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Diamond/carbon nanotube composites: Raman, FTIR and XPS spectroscopic studies

    Czech Academy of Sciences Publication Activity Database

    Varga, Marián; Ižák, Tibor; Vretenár, V.; Kozak, Halyna; Holovský, Jakub; Artemenko, Anna; Hulman, M.; Skákalová, V.; Lee, D. S.; Kromka, Alexander

    2016-01-01

    Roč. 111, Jan (2016), s. 54-61 ISSN 0008-6223 R&D Projects: GA ČR GC15-22102J; GA MŠk(CZ) 7AMB14SK037 Institutional support: RVO:68378271 Keywords : diamond * carbon nanotubes * spectroscopy * Raman * FTIR * XPS Subject RIV: JI - Composite Materials Impact factor: 6.337, year: 2016

  16. Raman Spectroscopic Signature Markers of Dopamine-Human Dopamine Transporter Interaction in Living Cells.

    Science.gov (United States)

    Silwal, Achut P; Yadav, Rajeev; Sprague, Jon E; Lu, H Peter

    2017-07-19

    Dopamine (DA) controls many psychological and behavioral activities in the central nervous system (CNS) through interactions with the human dopamine transporter (hDAT) and dopamine receptors. The roles of DA in the function of the CNS are affected by the targeted binding of drugs to hDAT; thus, hDAT plays a critical role in neurophysiology and neuropathophysiology. An effective experimental method is necessary to study the DA-hDAT interaction and effects of variety of drugs like psychostimulants and antidepressants that are dependent on this interaction. In searching for obtaining and identifying the Raman spectral signatures, we have used surface enhanced Raman scattering (SERS) spectroscopy to record SERS spectra from DA, human embryonic kidney 293 cells (HEK293), hDAT-HEK293, DA-HEK293, and DA-hDAT-HEK293. We have demonstrated a specific 2D-distribution SERS spectral analytical approach to analyze DA-hDAT interaction. Our study shows that the Raman modes at 807, 839, 1076, 1090, 1538, and 1665 cm -1 are related to DA-hDAT interaction, where Raman shifts at 807 and 1076 cm -1 are the signature markers for the bound state of DA to probe DA-hDAT interaction. On the basis of density function theory (DFT) calculation, Raman shift of the bound state of DA at 807 cm -1 is related to combination of bending modes α(C3-O10-H21), α(C2-O11-H22), α(C7-C8-H18), α(C6-C4-H13), α(C7-C8-H19), and α(C7-C8-N9), and Raman shift at 1076 cm -1 is related to combination of bending modes α(H19-N9-C8), γ(N9-H19), γ(C8-H19), γ(N9-H20), γ(C8-H18), and α(C7-C8-H18). These findings demonstrate that protein-ligand interactions can be confirmed by probing change in Raman shift of ligand molecules, which could be crucial to understanding molecular interactions between neurotransmitters and their receptors or transporters.

  17. Lichen biomarkers upon heating: a Raman spectroscopic study with implications for extra-terrestrial exploration

    Science.gov (United States)

    Miralles, I.; Capel Ferrón, C.; Hernández, V.; López-Navarrete, J. T.; Jorge-Villar, S. E.

    2017-01-01

    Lithopanspermia Theory has suggested that life was transferred among planets by meteorites and other rocky bodies. If the planet had an atmosphere, this transfer of life had to survive drastic temperature changes in a very short time in its entry or exit. Only organisms able to endure such a temperature range could colonize a planet from outer space. Many experiments are being carried out by NASA and European Space Agency to understand which organisms were able to survive and how. Among the suite of instruments designed for extraplanetary exploration, particularly for Mars surface exploration, a Raman spectrometer was selected with the main objective of looking for life signals. Among all attributes, Raman spectroscopy is able to identify organic and inorganic compounds, either pure or in admixture, without requiring sample manipulation. In this study, we used Raman spectroscopy to examine the lichen Squamarina lentigera biomarkers. We analyse spectral signature changes after sample heating under different experimental situations, such as (a) laser, (b) analysis accumulations over the same spot and (c) environmental temperature increase. Our goal is to evaluate the capability of Raman spectroscopy to identify unambiguously life markers even if heating has induced spectral changes, reflecting biomolecular transformations. Usnic acid, chlorophyll, carotene and calcium oxalates were identified by the Raman spectra. From our experiments, we have seen that usnic acid, carotene and calcium oxalates (the last two have been suggested to be good biomarkers) respond in a different way to environmental heating. Our main conclusion is that despite their abundance in nature or their inorganic composition the resistance to heat makes some molecules more suitable than others as biomarkers.

  18. Raman spectroscopic study of synthetic pyrope-grossular garnets: structural implications

    Science.gov (United States)

    Du, Wei; Han, Baofu; Clark, Simon Martin; Wang, Yichuan; Liu, Xi

    2017-06-01

    A study of the effect of substitution of Mg and Ca in garnet solid solution (Grtss) was carried out using Raman spectroscopy to probe changes to the crystal lattice. The garnet solid solutions with composition changing along pyrope (Py; Mg3Al2Si3O12) and grossular (Gr; Ca3Al2Si3O12) binary were synthesized from glass at 6 GPa and 1400 °C and a second series of Grtss with composition Py40Gr60 were synthesized at 6 GPa but different temperatures from 1000 to 1400 °C. Raman mode assignments were made based on a comparison with the two end members pyrope and grossular, which show consistent result with literature study on single crystals data. The correlation between the Raman mode frequencies and compositional changes along the pyrope-grossular binary suggests a two-mode behavior for Mg and Ca cations in the garnet structure. The full widths at half-maximum of selected Raman modes increase on moving away from the end members and are about double the end-member values in the mid-position, where the frequencies closely linearly change with composition. The frequencies of the translational modes of the SiO4 tetrahedron (T(SiO4)) show large deviations from linearity indicating a strong kinematic coupling with the translational modes of the Ca and Mg cations. The anomalies in T(SiO4) are linked to mixing unit cell volume, suggesting that the nonlinear mixing volume behavior along the pyrope-grossular binary is related to the resistance of the Si-O bond to expansion and compression, which is caused by substitution of Mg and Ca cations in the dodecahedral sites. Annealing temperature also shows effect on Raman mode frequencies, but the main factor controlling the changes in mode frequencies along pyrope-grossular binary is composition.

  19. Ring distributions in alkali- and alkaline-earth aluminosilicate framework glasses- a raman spectroscopic study

    Science.gov (United States)

    Sharma, S.K.; Philpotts, J.A.; Matson, D.W.

    1985-01-01

    Raman spectra of crystalline polymorphs of a number of tectosilicate minerals having various sizes of smallest rings of TO4 tetrahedra (T = Si, Al) have been investigated to identify the bands that are sensitive indicators of the smallest rings in the network. The information obtained from the Raman spectra of tectosilicate minerals (e.g., SiO2 polymorphs, NaAlSi3O8 (Ab), NaAlSiO4 (Ne), KAlSi3O8 (Or), and KAlSi2O6 (Lc)) is used to interpret the Raman spectra of the isochemical glasses. It is shown that the frequency of the dominant ??s (TOT) band in the spectra of both crystals and glasses is related to the dominant size of TO4 rings in the structure. In agreement with previous X-ray RDF work, it is found that in the glasses of Ab and Jd (NaAlSi2O6) compositions, six-membered rings of TO4 tetrahedra predominate. The Raman spectrum of Or glass, however, indicates that clusters of intermixed four- and six-membered rings of TO4 tetrahedra, similar to those existing in crystalline leucite, are also present in the glass. Raman evidence indicates that four-membered rings of TO4 tetrahedra predominate in the glass of An composition. Similarly, the higher frequency of the ??s (TOT) band in the spectrum of Ne glass as compared with the frequency the ??s (TOT) band in the spectra of crystalline cargenieite and nephelite indicates either an admixture of the four- and six-membered rings or the puckering of six-membered rings in the glass structure. ?? 1985.

  20. Raman spectroscopic study of synthetic pyrope-grossular garnets: structural implications

    Science.gov (United States)

    Du, Wei; Han, Baofu; Clark, Simon Martin; Wang, Yichuan; Liu, Xi

    2018-02-01

    A study of the effect of substitution of Mg and Ca in garnet solid solution (Grtss) was carried out using Raman spectroscopy to probe changes to the crystal lattice. The garnet solid solutions with composition changing along pyrope (Py; Mg3Al2Si3O12) and grossular (Gr; Ca3Al2Si3O12) binary were synthesized from glass at 6 GPa and 1400 °C and a second series of Grtss with composition Py40Gr60 were synthesized at 6 GPa but different temperatures from 1000 to 1400 °C. Raman mode assignments were made based on a comparison with the two end members pyrope and grossular, which show consistent result with literature study on single crystals data. The correlation between the Raman mode frequencies and compositional changes along the pyrope-grossular binary suggests a two-mode behavior for Mg and Ca cations in the garnet structure. The full widths at half-maximum of selected Raman modes increase on moving away from the end members and are about double the end-member values in the mid-position, where the frequencies closely linearly change with composition. The frequencies of the translational modes of the SiO4 tetrahedron (T(SiO4)) show large deviations from linearity indicating a strong kinematic coupling with the translational modes of the Ca and Mg cations. The anomalies in T(SiO4) are linked to mixing unit cell volume, suggesting that the nonlinear mixing volume behavior along the pyrope-grossular binary is related to the resistance of the Si-O bond to expansion and compression, which is caused by substitution of Mg and Ca cations in the dodecahedral sites. Annealing temperature also shows effect on Raman mode frequencies, but the main factor controlling the changes in mode frequencies along pyrope-grossular binary is composition.

  1. Raman spectroscopic insights into the chemical gradients within the wound plug of the green alga Caulerpa taxifolia.

    Science.gov (United States)

    Weissflog, Ina A; Grosser, Katharina; Bräutigam, Maximilian; Dietzek, Benjamin; Pohnert, Georg; Popp, Juergen

    2013-04-15

    The invasive unicellular green macroalga Caulerpa taxifolia has spread dramatically in the Mediterranean Sea over the last decades. Its success is based on rapid plug formation after wounding, to prevent the loss of cell content. This quick and efficient process involves the rapid transformation of the secondary metabolite caulerpenyne to the reactive 1,4-dialdehyde oxytoxin 2, which acts as a protein crosslinker. The main metabolites of the wound plug were identified as proteins, caulerpenyne derivatives, and sulfated polysaccharides. Because of a methodological deficit, however, the detailed distribution of the compounds within the wound plug of C. taxifolia was unknown. This study demonstrates the suitability of FT-Raman spectroscopy for the noninvasive in vivo determination of caulerpenyne and its derivatives, as well as β-carotene, from signals with special spectral features within the wound plug and the adjacent intact alga tissue, with a resolution of 100 μm. FT-Raman spectra allowed four different zones with distinct chemical compositions around the region of wounds to be characterized. Gradients of the investigated metabolites within the wound plug and the alga could be determined. Moreover, various caulerpenyne derivatives could be identified spectroscopically, and this has led to a mechanistic proposal for the internal and the external wound plug formation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Thermal stability and hot-stage Raman spectroscopic study of Ca-montmorillonite modified with different surfactants: A comparative study

    International Nuclear Information System (INIS)

    Sun, Zhiming; Park, Yuri; Zheng, Shuilin; Ayoko, Godwin A.; Frost, Ray L.

    2013-01-01

    Highlights: • A typical Ca-montmorillonite was modified with three surfactants through ion exchange. • The organoclays were characterized by XRD, TG and hot stage Raman. • The structural geometry and thermal properties of organoclays were analyzed. • The prepared organoclays show potential prospects in the environmental remediation. - Abstract: Three long chain cationic surfactants were intercalated into Ca-montmorillonite through ion exchange and the obtained organoclays were characterized by X-ray diffraction (XRD), high resolution thermogravimetric analysis (TG) and Raman spectroscopy. The intercalation of surfactants not only changes the surface properties of clay from hydrophilic to hydrophobic but also greatly increases the basal spacing of the interlayers based on XRD analysis. The thermal stability of organoclays intercalated with three surfactants (TTAB, DTAB and CTAB) and the different arrangements of the surfactant molecules intercalated into Ca-montmorillonite were determined by TG-DTG analysis. A Raman spectroscopic study on the Ca-montmorillonite modified by three surfactants prepared at different concentrations provided the detailed conformational ordering of different intercalated long-chain surfactants under different conditions. The wavenumber of the antisymmetric stretching mode is more sensitive than that of the symmetric stretching mode to the mobility of the tail of the amine chain. At room temperature, the conformational ordering is more easily affected by the packing density in the lateral model. With the increase of the temperature, the positions of both the antisymmetric and symmetric stretching bands shift to higher wavenumbers, which indicates a decrease of conformational ordering. This study offers new insights into the structure and properties of Ca-montmorillonite modified with different long chain surfactants. Moreover, the experimental results confirm the potential applications of organic Ca-montmorillonites for the removal

  3. Raman spectroscopic studies of Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Nithya, R., E-mail: nithya@igcar.gov.in; Ravindran, T. R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, TN (India); Daniel, D. J. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam-603110, TN (India)

    2015-06-24

    Single crystals of Nd{sub 1-x}Sm{sub x}GaO{sub 3} (x= 0 and 0.25) were grown by a four mirror IR image furnace using floating zone technique. The crystals are characterized by X-ray diffraction and Raman spectroscopic measurements. NGO adopts orthorhombic structure with Pbnm symmetry and samarium substituted compound also exhibited the same structure as that of the pristine compound without secondary phases. Polarized Raman spectra are measured at ambient temperature in a back scattering geometry. Spectra exhibit low intensity first-order Raman bands. In addition, several high intensity second-order Raman bands have been observed in the frequency range 2000 to 4000 cm{sup −1}.

  4. Raman spectroscopic analysis of human remains from a seventh century cist burial on Anglesey, UK.

    Science.gov (United States)

    Edwards, Howell G M; Wilson, Andrew S; Nik Hassan, Nik F; Davidson, Andrew; Burnett, Andrew

    2007-02-01

    Specimens from human remains exhibiting unusual preservation excavated from a seventh century stone cist burial at Towyn y Capel in Anglesey, UK, have been analysed using Raman spectroscopy with near-infrared laser excitation at 1,064 and 785 nm. Specimens of hair and bone provided evidence for severe degradation and microbial colonisation. The deposits within the stone cist showed that some microbially mediated compounds had been formed. Analysis of crystals found at the interface between the hair and the skeletal neck vertebrae revealed a mixture of newberyite and haematite, associated with decomposition products of the hair and bone. An interesting differential degradation was noted in the specimens analysed which could be related to the air-void and the presence of plant root inclusions into the stone cist. This is the first time that Raman spectroscopy has been used in the forensic archaeological evaluation of burial remains in complex and dynamic environments.

  5. Raman and X-Ray photoelectron spectroscopic studies of graphene devices for identification of doping

    Science.gov (United States)

    Aydogan Gokturk, Pinar; Kakenov, Nurbek; Kocabas, Coskun; Suzer, Sefik

    2017-12-01

    Tunability of electronic properties of graphene is one of the most promising properties to integrate it to high efficiency devices in the field of electronics. Here we demonstrate the substrate induced doping of CVD graphene devices using polymers with different functional groups. Both X-Ray secondary electron cut-off and Raman spectra confirm p-type doping of a PVC-Graphene film when compared to a PMMA-Graphene one. We also systematically analyzed the reversible doping effect of acid-base exposure and UV illumination to further dope/undope the polymer supported graphene devices. The shifts in the Raman 2D band towards lower and then to higher wavenumbers, with sequential exposure to ammonia and hydrochloric acid vapors, suggest n-type doing and restoration of graphene to its original state. Finally, the n-type doping with UV irradiation on half-covered samples was utilized and shown by both XPS and Raman to create two regions with different electronic properties and resistances. These type of controlled and reversible doping routes offer new paths for electronic devices especially towards fabricating graphene p-n junctions.

  6. NIR-FT-Raman spectroscopic studies of hexammine and pentammine chromium(III) complexes

    Science.gov (United States)

    Chen, Yuying; Christensen, Daniel H.; Sørensen, Georg O.; Nielsen, Ole Faurskov; Jacobsen, Claus J. H.; Hyldtoft, Jens

    1994-03-01

    The NIR-FT-Raman spectra are presented for the hexammine [Cr(NH 3) 6]X 3 (where X = Br -, NO -3), pentamminechloro [Cr(NH 3) 5Cl]X 2 (where X = Cl -, ClO -4), and pentammineaqua [Cr(NH 3) 5(H 2O)]X 3 (where X = ClO -4, CF 3SO -3) chromium(III) complexes. The NIR-FT-Raman spectra, with an excitation wavelength of 1064 nm, were obtained at room temperature without problems from the strongly colored samples, which often cause problems with excitation by lasers in the visible region. All the Raman frequencies observed from the complexes have been assigned to the skeleton vibrational region from 100 to 600 cm -1. The symmetry and the general valence force constants for the bonds chromium(III)nitrogen, chromium(III)oxygen and chromium(III)chloro have been obtained. The nature of the metalligand bond between chromium(III) ammine complexes has been compared with recent results obtained for similar cobalt(III) ammine complexes.

  7. High-pressure measuring cell for Raman spectroscopic studies of natural gas

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    A system for obtaining Raman spectra of gases at high pressure has been constructed. In order to ensure that a natural gas sample is totally representative, a high-pressure gas-measuring cell has been developed, built up by stainless steel fittings and a sapphire tube. The design and construction...... of this cell are described. A perfect pressure seal has been demonstrated up to 15.0 MPaA (MPa absolute). The cell has been successfully used to obtain Raman spectra of natural gas samples. Some of these spectra are presented and assigned. The most remarkable observation in the spectra is that it is possible...... to detect hydrogen sulfide at concentrations of 1-3 mg H2S/Nm(3). An attempt to make a quantitative analysis of natural gas by the so-called "ratio method" is presented. In addition to this, the relative normalized differential Raman scattering cross sections for ethane and i-butane molecules at 8.0 MPa...

  8. Raman spectroscopic analysis of cyanobacterial colonization of hydromagnesite, a putative martian extremophile

    Science.gov (United States)

    Edwards, Howell G. M.; Moody, Caroline D.; Newton, Emma M.; Villar, Susana E. Jorge; Russell, Michael J.

    2005-06-01

    Raman spectra of an extremophile cyanobacterial colony in hydromagnesite from Lake Salda in Turkey have revealed a biogeological modification which is manifest as aragonite in the stratum associated with the colony. The presence of key spectral biomarkers of organic protectant molecules such as β-carotene and scytonemin indicate that the survival strategy of the cyanobacteria is significantly one of UV-radiation protection. The terrestrial location of this extremophile is worthy of consideration further because of its possible putative link with the "White Rock" formations in Sabaea Terra and Juventae Chasma on Mars.

  9. Raman spectra and DFT calculations for botryococcene and methylsqualene hydrocarbons from the B race of the green microalga Botryococcus braunii

    Science.gov (United States)

    Tatli, Mehmet; Chun, Hye Jin; Camp, Charles H.; Li, Jingting; Cicerone, Marcus T.; Shih, Wei-Chuan; Laane, Jaan; Devarenne, Timothy P.

    2017-11-01

    Botryococcus braunii, a green colonial microalga, is a prodigious producer of liquid hydrocarbon oils that can be used as renewable feedstocks for producing combustion engine fuels. The B race of B. braunii mainly produces the triterpene hydrocarbons known as botryococcenes, which have over twenty known structures. Minor hydrocarbons in the B race include the triterpene methylsqualenes. Here we report an examination of the molecular structure for ten botryococcenes and five methylsqualenes using Raman spectroscopy and density functional theory (DFT) calculations in an effort to distinguish between these structurally similar molecules by spectroscopic approaches. The DFT calculations show that these molecules have between 243 and 271 vibrational frequencies. A comparison of the experimental Raman spectroscopy and DFT calculations indicates several spectral regions such as those for ν(Cdbnd C) stretching, CH2/CH3 bending, and ring bending can be used to distinguish between these molecules. In an extension of this analysis, a broadband coherent anti-Stokes Raman spectroscopy (BCARS) analysis was used to clearly distinguish between several botryococcenes isomers.

  10. Raman spectroscopic detection of peripheral nerves towards nerve-sparing surgery

    Science.gov (United States)

    Minamikawa, Takeo; Harada, Yoshinori; Takamatsu, Tetsuro

    2017-02-01

    The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery, namely nerve-sparing surgery, is now promising technique to avoid functional deficits of the limbs and organs following surgery as an aspect of the improvement of quality of life of patients. Detection of peripheral nerves including myelinated and unmyelinated nerves is required for the nerve-sparing surgery; however, conventional nerve identification scheme is sometimes difficult to identify peripheral nerves due to similarity of shape and color to non-nerve tissues or its limited application to only motor peripheral nerves. To overcome these issues, we proposed a label-free detection technique of peripheral nerves by means of Raman spectroscopy. We found several fingerprints of peripheral myelinated and unmyelinated nerves by employing a modified principal component analysis of typical spectra including myelinated nerve, unmyelinated nerve, and adjacent tissues. We finally realized the sensitivity of 94.2% and the selectivity of 92.0% for peripheral nerves including myelinated and unmyelinated nerves against adjacent tissues. Although further development of an intraoperative Raman spectroscopy system is required for clinical use, our proposed approach will serve as a unique and powerful tool for peripheral nerve detection for nerve-sparing surgery in the future.

  11. Conformational aspects of dibenzo-tetroxecin: A structural, Raman spectroscopic and computational study

    Science.gov (United States)

    Gordon, Keith C.; McAdam, C. John; Moratti, Stephen C.; Shillito, Georgina E.; Simpson, Jim

    2017-10-01

    Crystalline dibenzo-tetroxecin (I) has been prepared from a reaction between catechol and dichloromethane and its molecular and crystal structure, together with the Raman spectrum of the material in the solid state and in solution, is reported. The molecular structure shows the molecule adopts an anti or stepped conformation. Density functional theory (DFT) optimisation and frequency calculations using the B3LYP functional with the 6-31G(d) basis set showed the presence of syn- and anti-conformers of (I), with the anti-conformer predicted to be the lower in energy by 13.6 kJ mol-1. The vibrational frequencies and relative Raman intensities of the anti-conformer are well modelled by the DFT calculations. The bond lengths and angles obtained for the anti-conformer are also in good agreement with the crystal structure. The crystal structure of (I) is stabilised by intermolecular Csbnd H⋯O hydrogen bonds that generate a three dimensional network.

  12. Doping of C60 fullerene peapods with lithium vapor: Raman spectroscopic and spectroelectrochemical studies.

    Science.gov (United States)

    Kalbác, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, Lothar

    2008-01-01

    Raman spectroscopy and in situ Raman spectroelectrochemistry have been applied to the study of the lithium vapor doping of C60@SWCNTs (peapods; SWCNT=single-walled carbon nanotube). A strong degree of doping was proven by the disappearance of the radial breathing mode (RBM) of the SWCNTs and by the attenuation of the tangential (TG) band intensity by two orders of magnitude. The lithium doping causes a downshift of the Ag(2) mode of the intratubular C60 by 27 cm(-1) and changes the resonance condition of the encapsulated fullerene. In contrast to potassium vapor doping, the strong downshift of the TG band was not observed for lithium doping. The peapods treated with lithium vapor remained partially doped even when they were exposed to humid air. This was reflected by a reduction in the intensity of the nanotube and the fullerene modes and by the change in the shape of the RBM band compared with that of the undoped sample. The Ag(2) mode of the intratubular fullerene was not resolved after contact of the lithium-doped sample with water. Lithium insertion into the interior of a peapod and its strong interaction with the intratubular fullerene is suggested to be responsible for the air-insensitive residual doping. This residual doping was confirmed by in situ spectroelectrochemical measurements. The TG band of the lithium-doped peapods did not undergo an upshift during the anodic doping, which points to the formation of a stable exohedral metallofullerene peapod.

  13. Raman spectroscopic study of phosphogypsum thermal reduction with the carbonaceous material.

    Science.gov (United States)

    Msila, Xolani; Barnard, Werner; Billing, Dave G

    2015-10-05

    Elemental sulphur (S) can be produced from hydrogen sulphide (H2S) in a PiPco or Iron process. In turn H2S can be stripped with carbon dioxide (CO2) from calcium sulphide (CaS) obtained from the thermal reduction of phosphogypsum with carbon. The reaction pathway for the thermal reduction of the phosphogypsum with graphite was studied using thermogravimetric analysis and in situ Raman spectroscopy. The dehydration of the phosphogypsum to anhydrite was completed at about 142 °C. The dehydration was followed by the formation of the intermediate compound at about 860 °C which is characterised by a mass loss of about 11%. The intermediate compound, identified using the in situ Raman spectroscopy to be a dehydrated orschallite-type compound (Ca3[SO4][SO3]2), converted to CaS at about 935 °C. The presence of the metal impurities in the phosphogypsum: Ni(2+)(4 mg kg(-1)); Co(2+)(2 mg kg(-1)); Mn(2+)(5 mg kg(-1)); Cu(2+)(14 mg kg(-1)); Fe(2+)(200 mg kg(-1)) and Mg(2+)(300 mg kg(-1)) showed no influence the onset temperature for the reduction reaction. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, R.; Premkumar, S.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com [Department of Physics, N.M.S.S.V.N College, Madurai-625019, Tamilnadu, India. (India); Rekha, T. N. [PG and Research Department of Physics, Lady Doak College, Madurai-625 002, Tamilnadu, India. (India)

    2016-05-06

    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ∼55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  15. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    International Nuclear Information System (INIS)

    Premkumar, R.; Premkumar, S.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin; Rekha, T. N.

    2016-01-01

    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ∼55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  16. In situ Raman spectroscopic study of marble capitals in the Alhambra monumental ensemble

    Science.gov (United States)

    Arjonilla, Paz; Domínguez-Vidal, Ana; de la Torre López, María José; Rubio-Domene, Ramón; Ayora-Cañada, María José

    2016-12-01

    The marble capitals of five different sites in the Alhambra complex (Granada, Spain), namely the Mexuar, the Hall of the Abencerrages, the Hall of the Kings, the Court of the Myrtles and the Court of the Main Canal, have been investigated. The decoration of the capitals exhibits mainly blue, red, black and gilding motifs with different states of conservation. The work has been carried out in situ by means of a portable Raman micro-spectrometer with an excitation laser of 785 nm. In addition to preserving the artwork with a non-invasive study, the on-site investigation gives a more representative knowledge of the art objects because the measurements are not limited to the samples that can be taken (few and small). The obtained Raman spectra were of good quality despite challenging adverse conditions out of the laboratory. Cinnabar, minium, carbon black, natural lapis lazuli and azurite were the main pigments found. Synthetic ultramarine blue was also detected in a capital as a result of a modern restoration. Degradation products as tin oxide in the gildings and weddellite in the preparation layers were also identified. All the results together with a careful visual inspection can be combined to elucidate the different execution techniques employed to apply the pigments on the marble substrate of the capitals in the Nasrid and Christian periods.

  17. Anti-Stokes emissions and determination of Stark sub-level diagram of Er{sup 3+} ions in KY{sub 3}F{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Boulma, E [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Diaf, M [Departement de Physique, Universite Badji Mokhtar Annaba, BP12, 23000 Annaba, Algerie (Germany); Jouart, J P [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Bouffard, M [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Doualan, J L [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France); Moncorge, R [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France)

    2006-07-26

    We are interested, in this work, in determining the Stark sub-level of Er{sup 3+} ions doping a KY{sub 3}F{sub 10} single crystal with a molar concentration of 1%. We have used a new method of measurement of energies of the ground level and emitting levels from excitation and anti-Stokes emission spectra recorded at liquid nitrogen temperature. This technique is based on a spectral analysis of the anti-Stokes emissions recorded after selective excitation with a red dye tunable laser. Thus, we could determine the Stark sub-levels of the ground and the principal emitting levels in the infrared, visible and near-UV ranges with a very good precision.

  18. Anti-Stokes emissions and determination of Stark sub-level diagram of Er3+ ions in KY3F10

    International Nuclear Information System (INIS)

    Boulma, E; Diaf, M; Jouart, J P; Bouffard, M; Doualan, J L; Moncorge, R

    2006-01-01

    We are interested, in this work, in determining the Stark sub-level of Er 3+ ions doping a KY 3 F 10 single crystal with a molar concentration of 1%. We have used a new method of measurement of energies of the ground level and emitting levels from excitation and anti-Stokes emission spectra recorded at liquid nitrogen temperature. This technique is based on a spectral analysis of the anti-Stokes emissions recorded after selective excitation with a red dye tunable laser. Thus, we could determine the Stark sub-levels of the ground and the principal emitting levels in the infrared, visible and near-UV ranges with a very good precision

  19. Spectroscopic characterization of enzymatic flax retting: Factor analysis of FT-IR and FT-Raman data

    Science.gov (United States)

    Archibald, D. D.; Henrikssen, G.; Akin, D. E.; Barton, F. E.

    1998-06-01

    Flax retting is a chemical, microbial or enzymatic process which releases the bast fibers from the stem matrix so they can be suitable for mechanical processing before spinning into linen yarn. This study aims to determine the vibrational spectral features and sampling methods which can be used to evaluate the retting process. Flax stems were retted on a small scale using an enzyme mixture known to yield good retted flax. Processed stems were harvested at various time points in the process and the retting was evaluated by conventional methods including weight loss, color difference and Fried's test, a visual ranking of how the stems disintegrate in hot water. Spectroscopic measurements were performed on either whole stems or powders of the fibers that were mechanically extracted from the stems. Selected regions of spectra were baseline and amplitude corrected using a variant of the multiplicative signal correction method. Principal component regression and partial least-squares regression with full cross-validation were used to determine the spectral features and rate of spectral transformation by regressing the spectra against the retting time in hours. FT-Raman of fiber powders and FT-IR reflectance of whole stems were the simplest and most precise methods for monitoring the retting transformation. Raman tracks the retting by measuring the decrease in aromatic signal and subtle changes in the C-H stretching vibrations. The IR method uses complex spectral features in the fingerprint and carbonyl region, many of which are due to polysaccharide components. Both spectral techniques monitor the retting process with greater precision than the reference method.

  20. Raman spectroscopic analysis of oral cells in the high wavenumber region.

    Science.gov (United States)

    Carvalho, Luis Felipe C S; Bonnier, Franck; Tellez, Cláudio; Dos Santos, Laurita; O'Callaghan, Kate; O'Sullivan, Jeff; Soares, Luis Eduardo S; Flint, Stephen; Martin, Airton A; Lyng, Fiona M; Byrne, Hugh J

    2017-12-01

    Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with submicrometer spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1800cm -1 ) has been shown to be very promising for optical biopsy purposes. However, limitations for discrimination of dysplastic and inflammatory processes based on the fingerprint region have been demonstrated. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2800-3600cm -1 ) provides more specific information based on NH, OH and CH vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the high-wavenumber spectral region in this context by collecting Raman spectra of nucleolus, nucleus and cytoplasm from oral epithelial cancer (SCC-4) and dysplastic (DOK) cell lines and from normal oral epithelial primary cells, in vitro, in water immersion, which were then analyzed by principal components analysis as a method to discriminate the spectra. Analysis was performed before and after digital subtraction of the bulk water signal. In the normal cell line, the three subcellular regions are well differentiated before water subtraction, although the discrimination of the two nuclear regions is less well defined after water subtraction. Comparing the respective subcellular regions of the three cell lines, before water subtraction, the cell lines can be discriminated using sequential PCA and Feature Discriminant Analysis with up to ~100% sensitivity and 97% specificity for the cytoplasm, which is improved to 100% sensitivity and 99% specificity for the nucleus. The results are discussed in terms of discrimination comparing the

  1. An in situ resonance Raman and infrared spectroscopic study of hexacyanoferrate (II) ion adsorbed to aqueous colloidal TiO 2

    Science.gov (United States)

    Umapathy, S.; McQuillan, A. J.; Hester, R. E.

    1990-06-01

    Resonance Raman and Fourier-transform infrared spectroscopies have been used to study the charge-transfer reactions of adsorbed hexacyanoferrate(II) on colloidal TiO 2. The spectroscopic results are analysed in terms of the molecular symmetry imposed by the various possible orientations of hexacyanoferrate(II) on the TiO 2 surface. It is concluded that the hexacyanoferrate(II) is adsorbed onto colloidal TiO 2 via either one or two CN groups.

  2. Long-Term Structural Modification of Water under Microwave Irradiation: Low-Frequency Raman Spectroscopic Measurements

    Directory of Open Access Journals (Sweden)

    A. V. Yakunov

    2017-01-01

    Full Text Available Raman scattering has been used to study the influence of 2.45 GHz microwave on the structure of water. It has been shown that treatment of the distilled water samples by electromagnetic field leads to long-term changes in the vibrational density of states. It was established that the retention time of structural changes of the water samples depends on the sample volume. The experimental results have been interpreted on the basis of the percolation model. It has been suggested that the change in the chemical composition of the water treated by microwaves can lead to a change in the structure of the percolation cluster formed by the network of hydrogen bonds. The time of the equilibrium structure recovery of the percolation cluster after termination of the microwaves depends on the cluster size and is much slower than the recovery in the chemical composition of water.

  3. Synergistic effects of atmospheric pressure plasma-emitted components on DNA oligomers: a Raman spectroscopic study.

    Science.gov (United States)

    Edengeiser, Eugen; Lackmann, Jan-Wilm; Bründermann, Erik; Schneider, Simon; Benedikt, Jan; Bandow, Julia E; Havenith, Martina

    2015-11-01

    Cold atmospheric-pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi-resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X-jet technology separates plasma-generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro. Schematics of DNA oligomer treatment with cold atmospheric-pressure plasma. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. An analytical Raman spectroscopic study of an important english oil painting of the 18th Century

    Science.gov (United States)

    Edwards, Howell G. M.; Vandenabeele, Peter; Jehlicka, Jan; Benoy, Timothy J.

    2014-01-01

    An opportunity was afforded to analyse pigment specimens from an unrestored oil painting in the style of the English School of the mid-18th Century prior to conservation being undertaken. Raman spectroscopy was adopted to characterise the pigments and indicated the presence of a novel red pigment which was assigned to the complex chromium mineral, hemihedrite, in addition to other interesting materials found in combination. This is the first recorded identification of hemihedrite spectral signals in an art context in a range of mineral pigments that are otherwise typical of this period and some hypotheses are presented to explain its presence based on its occurrence with associated mineral pigments. It is suggested that the presence of powdered glass identified in certain areas of the painting enhanced the reflectivity of the pigment matrix.

  5. Understanding Sulfide Capacity of Molten Aluminosilicates via Structural Information from 'Raman' and 'NMR' Spectroscopic Methodologies

    Science.gov (United States)

    Park, Joo Hyun

    The effect of Ca-Mn substitution on the sulfide capacity of the MnO-CaO-SiO2 (-Al2O3-MgO) melts were explained from the Raman scattering data, from which the structure information for the network modifying role and sulfur stabilizing role of Ca2+ and Mn2+ ions were obtained. The effect of Ce2O3 on the sulfide capacity of the MnO-SiO2-Al2O3-Ce2O3 melts were understood based on the structure data, from which the charge compensating role of Ce3+ and the amphoteric behavior of alumina were obtained. Employing the structure analysis, the thermochemical properties such as capacity of the oxide melts with no thermodynamic data can be understood in terms of `composition-structure-property' relationship.

  6. Single molecule Raman spectroscopic assay to detect transgene from GM plants.

    Science.gov (United States)

    Kadam, Ulhas S; Chavhan, Rahul L; Schulz, Burkhard; Irudayaraj, Joseph

    2017-09-01

    Substantial concerns have been raised for the safety of transgenics on human health and environment. Many organizations, consumer groups, and environmental agencies advocate for stringent regulations to avoid transgene products' contamination in food cycle or in nature. Here we demonstrate a novel approach using surface enhanced Raman spectroscopy (SERS) to detect and quantify transgene from GM plants. We show a highly sensitive and accurate quantification of transgene DNA from multiple transgenic lines of Arabidopsis. The assay allows us to detect and quantify the transgenes as low as 0.10 pg without need for PCR-amplification. This technology is relatively cheap, quick, simple, and suitable for detection at low target concentration. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Controlled Clustering of Gold Nanoparticles using Solid-support for Surface-enhanced Raman Spectroscopic Probes

    International Nuclear Information System (INIS)

    Chang, Hyejin; Chae, Jinjoo; Jeong, Hong; Kang, Homan; Lee, Yoonsik

    2014-01-01

    We fabricated small clusters of gold nanoparticles by using solid-supported aggregation of gold nanoparticles. The fabricated Au nanoclusters consisting mainly of dimers showed homogeneous characteristics in cluster size and SERS intensity. The SERS enhancement of 4-ABT molecules in an effective area within 2-nm gap appeared to be approximately 10. Detachment process by ultrasonication was successively carried out in order to use the nanoclusters as SERS probes. The possibility of these clusters as SERS probe was proved in terms of signal and cluster size. Single molecule-level sensitivity of surface-enhanced Raman scattering (SERS) was known approximately fifteen years ago. Ever since there have been many different applications benefiting from the ultra-high sensitivity such as single molecule detection, chemical sensing and bio-molecular probes. Especially, SERS has drawn much attention in bio-multiplexing probes owing to its unique optical characteristics claiming extremely narrow bandwidth, high sensitivity of light signals, and non-bleaching feature

  8. Rapid bacterial antibiotic susceptibility test based on simple surface-enhanced Raman spectroscopic biomarkers

    Science.gov (United States)

    Liu, Chia-Ying; Han, Yin-Yi; Shih, Po-Han; Lian, Wei-Nan; Wang, Huai-Hsien; Lin, Chi-Hung; Hsueh, Po-Ren; Wang, Juen-Kai; Wang, Yuh-Lin

    2016-03-01

    Rapid bacterial antibiotic susceptibility test (AST) and minimum inhibitory concentration (MIC) measurement are important to help reduce the widespread misuse of antibiotics and alleviate the growing drug-resistance problem. We discovered that, when a susceptible strain of Staphylococcus aureus or Escherichia coli is exposed to an antibiotic, the intensity of specific biomarkers in its surface-enhanced Raman scattering (SERS) spectra drops evidently in two hours. The discovery has been exploited for rapid AST and MIC determination of methicillin-susceptible S. aureus and wild-type E. coli as well as clinical isolates. The results obtained by this SERS-AST method were consistent with that by the standard incubation-based method, indicating its high potential to supplement or replace existing time-consuming methods and help mitigate the challenge of drug resistance in clinical microbiology.

  9. Applying Full Spectrum Analysis to a Raman Spectroscopic Assessment of Fracture Toughness of Human Cortical Bone.

    Science.gov (United States)

    Makowski, Alexander J; Granke, Mathilde; Ayala, Oscar D; Uppuganti, Sasidhar; Mahadevan-Jansen, Anita; Nyman, Jeffry S

    2017-10-01

    A decline in the inherent quality of bone tissue is a † Equal contributors contributor to the age-related increase in fracture risk. Although this is well-known, the important biochemical factors of bone quality have yet to be identified using Raman spectroscopy (RS), a nondestructive, inelastic light-scattering technique. To identify potential RS predictors of fracture risk, we applied principal component analysis (PCA) to 558 Raman spectra (370-1720 cm -1 ) of human cortical bone acquired from 62 female and male donors (nine spectra each) spanning adulthood (age range = 21-101 years). Spectra were analyzed prior to R-curve, nonlinear fracture mechanics that delineate crack initiation (K init ) from crack growth toughness (K grow ). The traditional ν 1 phosphate peak per amide I peak (mineral-to-matrix ratio) weakly correlated with K init (r = 0.341, p = 0.0067) and overall crack growth toughness (J-int: r = 0.331, p = 0.0086). Sub-peak ratios of the amide I band that are related to the secondary structure of type 1 collagen did not correlate with the fracture toughness properties. In the full spectrum analysis, one principal component (PC5) correlated with all of the mechanical properties (K init : r = - 0.467, K grow : r = - 0.375, and J-int: r = - 0.428; p toughness, namely age and/or volumetric bone mineral density (vBMD), were included in general linear models as covariates, several PCs helped explain 45.0% (PC5) to 48.5% (PC7), 31.4% (PC6), and 25.8% (PC7) of the variance in K init , K grow , and J-int, respectively. Deriving spectral features from full spectrum analysis may improve the ability of RS, a clinically viable technology, to assess fracture risk.

  10. Femtosecond coherent nuclear dynamics of excited tetraphenylethylene: Ultrafast transient absorption and ultrafast Raman loss spectroscopic studies

    Science.gov (United States)

    Kayal, Surajit; Roy, Khokan; Umapathy, Siva

    2018-01-01

    Ultrafast torsional dynamics plays an important role in the photoinduced excited state dynamics. Tetraphenylethylene (TPE), a model system for the molecular motor, executes interesting torsional dynamics upon photoexcitation. The photoreaction of TPE involves ultrafast internal conversion via a nearly planar intermediate state (relaxed state) that further leads to a twisted zwitterionic state. Here, we report the photoinduced structural dynamics of excited TPE during the course of photoisomerization in the condensed phase by ultrafast Raman loss (URLS) and femtosecond transient absorption (TA) spectroscopy. TA measurements on the S1 state reveal step-wise population relaxation from the Franck-Condon (FC) state → relaxed state → twisted state, while the URLS study provides insights on the vibrational dynamics during the course of the reaction. The TA spectral dynamics and vibrational Raman amplitudes within 1 ps reveal vibrational wave packet propagating from the FC state to the relaxed state. Fourier transformation of this oscillation leads to a ˜130 cm-1 low-frequency phenyl torsional mode. Two vibrational marker bands, Cet=Cet stretching (˜1512 cm-1) and Cph=Cph stretching (˜1584 cm-1) modes, appear immediately after photoexcitation in the URLS spectra. The initial red-shift of the Cph=Cph stretching mode with a time constant of ˜400 fs (in butyronitrile) is assigned to the rate of planarization of excited TPE. In addition, the Cet=Cet stretching mode shows initial blue-shift within 1 ps followed by frequency red-shift, suggesting that on the sub-picosecond time scale, structural relaxation is dominated by phenyl torsion rather than the central Cet=Cet twist. Furthermore, the effect of the solvent on the structural dynamics is discussed in the context of ultrafast nuclear dynamics and solute-solvent coupling.

  11. Romano-British wall paintings: Raman spectroscopic analysis of fragments from two urban sites of early military colonisation

    Science.gov (United States)

    Edwards, H. G. M.; Middleton, P. S.; Hargreaves, M. D.

    2009-08-01

    Raman spectroscopic analyses of 1st century AD Romano-British villa wall-painting fragments from two important military and early urban centres at Colchester and Lincoln have demonstrated some interesting contrasts in technique and palette usage. Colchester, the earliest fortified settlement, developed a sophisticated painting and craft industry compared with Lincoln in the assimilation of novel substrate preparation ideas and pigment adoption. The earliest use of the rather rare purple mineral pigment, caput mortuum, hitherto reported in only a few Roman villas elsewhere in mainland Europe, is in evidence in this early phase settlement and the use of gypsum as a special ground preparation agent as an additive to the more common limewash putty to enhance the effect of the use of lazurite as a pigment is worthy of note in this context. Otherwise, the pigments are seen to be those that are quite normally encountered in Roman villas, namely, haematite, goethite, terre verte, and carbon. The results of this study indicate that at Colchester there was a continued development in technique into the colonial phase compared with a stagnation in Lincoln; these scientific results have created a stimulus for further historical research into pigment and techniques development for wall paintings at the fringe of the Roman Empire in the 1st-3rd Centuries AD.

  12. Romano-British wall paintings: Raman spectroscopic analysis of fragments from two urban sites of early military colonisation.

    Science.gov (United States)

    Edwards, H G M; Middleton, P S; Hargreaves, M D

    2009-08-01

    Raman spectroscopic analyses of 1st century AD Romano-British villa wall-painting fragments from two important military and early urban centres at Colchester and Lincoln have demonstrated some interesting contrasts in technique and palette usage. Colchester, the earliest fortified settlement, developed a sophisticated painting and craft industry compared with Lincoln in the assimilation of novel substrate preparation ideas and pigment adoption. The earliest use of the rather rare purple mineral pigment, caput mortuum, hitherto reported in only a few Roman villas elsewhere in mainland Europe, is in evidence in this early phase settlement and the use of gypsum as a special ground preparation agent as an additive to the more common limewash putty to enhance the effect of the use of lazurite as a pigment is worthy of note in this context. Otherwise, the pigments are seen to be those that are quite normally encountered in Roman villas, namely, haematite, goethite, terre verte, and carbon. The results of this study indicate that at Colchester there was a continued development in technique into the colonial phase compared with a stagnation in Lincoln; these scientific results have created a stimulus for further historical research into pigment and techniques development for wall paintings at the fringe of the Roman Empire in the 1st-3rd Centuries AD.

  13. Magnetoelectric and Raman spectroscopic studies of monocrystalline MnC r2O4

    Science.gov (United States)

    Lin, G. T.; Wang, Y. Q.; Luo, X.; Ma, J.; Zhuang, H. L.; Qian, D.; Yin, L. H.; Chen, F. C.; Yan, J.; Zhang, R. R.; Zhang, S. L.; Tong, W.; Song, W. H.; Tong, P.; Zhu, X. B.; Sun, Y. P.

    2018-02-01

    MnC r2O4 that exhibits spin frustration and complex spiral spin order is of great interest from both fundamental as well as application-oriented perspectives. Unlike CoC r2O4 , whose ground state presents the coexistence of commensurate spiral spin order (CSSO) and ferroelectric order, MnC r2O4 shows no multiferroicity. One reason is that the spiral spin order is highly sensitive to the oxygen concentration in MnC r2O4 . Here, we have successfully grown high-quality single-crystalline MnC r2O4 by the chemical vapor transport method. We observe a first-order magnetic transition from the incommensurate spiral spin order (ICSSO) at 19.4 K to the CSSO at 17.4 K. This magnetic transition is verified by magnetization, specific heat, and magnetoelectric measurements, which also confirm that the ground state exhibits the coexistence of the CSSO and magnetoelectricity below 17.4 K. Interestingly, the temperature evolution of Raman spectra between 5.4 and 300 K suggests that the structure remains the same. We also find that the phase-transition temperature of the CSSO decreases as applied magnetic field increases up to 45 kOe.

  14. Internal structure changes in bleached black human hair resulting from chemical treatments: A Raman spectroscopic investigation

    Science.gov (United States)

    Kuzuhara, Akio

    2014-11-01

    In order to investigate in detail the influence of chemical treatments (reduction, hydrolyzed eggwhite protein (HEWP) treatment, and oxidation) on damaged hair keratin fibers, the structure of cross-sections at various depths of excessively bleached (damaged) black human hair resulting from a permanent waving process was directly analyzed using Raman spectroscopy. It was found that L-cysteine (CYS) largely reacted with the gauche-gauche-gauche (GGG) conformation of disulfide (-SS-) groups (while CYS did not react with the trans-gauche-trans (TGT) conformation). In particular, not only the GGG content, but also the cysteic acid content existing throughout the cortex region of the excessively bleached human hair remarkably decreased by performing the oxidation process after reduction. On the other hand, the GGG content of the excessively bleached black human hair increased, while the TGT content decreased by performing the oxidation process after reduction and then HEWP treatment processes. From these experiments, the authors concluded that some of the keratin associated protein (KAP), which has a rich -SS- content and cysteic acid content was eluted from the cortex region along with the disconnection of -SS- groups, thereby leading to the remarkable reduction in the reconnection of -SS- groups of the excessively bleached black human hair after the permanent waving process (the reduction and oxidation processes). Also, the authors concluded that the HEWP treatment process in the permanent waving process caused the reconstruction of the KAP, thereby contributing to the acceleration of the reconnection of -SS- groups during the oxidation process.

  15. Resonance Raman Spectroscopic Evaluation of Skin Carotenoids as a Biomarker of Carotenoid Status for Human Studies

    Science.gov (United States)

    Mayne, Susan T.; Cartmel, Brenda; Scarmo, Stephanie; Jahns, Lisa; Ermakov, Igor V.; Gellermann, Werner

    2013-01-01

    Resonance Raman Spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of this biomarker, including its reproducibility, validity, feasibility for use in field settings, and factors that affect the biomarker such as diet, smoking, and adiposity. Recent studies have evaluated the response of the biomarker to controlled carotenoid interventions, both supplement-based and dietary [e.g., provision of a high-carotenoid fruit and vegetable (F/V)-enriched diet], demonstrating consistent response to intervention. The totality of evidence supports the use of skin carotenoid status as an objective biomarker of F/V intake, although in the cross-sectional setting, diet explains only some of the variation in this biomarker. However, this limitation is also a strength in that skin carotenoids may effectively serve as an integrated biomarker of health, with higher status reflecting greater F/V intake, lack of smoking, and lack of adiposity. Thus, this biomarker holds promise as both a health biomarker and an objective indicator of F/V intake, supporting its further development and utilization for medical and public health purposes. PMID:23823930

  16. Heating stage Raman and infrared emission spectroscopic study of the dehydroxylation of synthetic Mg-hydrotalcite

    International Nuclear Information System (INIS)

    Kloprogge, J.T.; Hickey, L.; Frost, R.L.

    1998-01-01

    Spectroscopy (IES) and heating stage Raman microscopy. Heating stage Raman microscopy reveals that upon heating and subsequent dehydration the bands at 553, 1052, 3503, 3603 and 3689 cm -1 associated with the (Mg, A1) 3 -OH translation, deformation and stretching vibrations decrease in intensity due to changes in the stacking order of the hydroxide layers. During this rearrangement around 150-175deg C the free interlayer nitrate forms a type of bridging nitrato complex with the metals in the hydroxide layers as evidenced by the disappearance of the normal free nitrate vibrations at 716, 1067 and 1386 cm -1 and the formation of a new band at 1039 cm -1 . Further heating to 300 deg C results in the dehydroxylation and decarbonisation of the hydrotalcite, which is only partially reversed upon cooling in air over a period of more than 12 hours. The Mg-hydrotalcite IES spectra show major changes around 350-400 deg C indicating the end of the dehydroxylation. In this temperature range Al-OH bands at 772, 923 and 1029 cm -1 disappear. New bands are observed around 713, 797 and 1075 cm -1 . The first and the last band plus the 545 cm -1 band indicate the formation of spinel (MgAl 2 O 4 ). The band around 713 cm -1 is also close to the ν LO position of MgO at 717 cm -1 , which is another product formed after dehydroxylation. However, decarbonisation is not complete at this stage as evidenced by both a continuing weight loss in the TGA up to at least 625 deg C and a decreasing carbonate signal in the IES up to 800 deg C

  17. Surface enhanced Raman spectroscopic direct determination of low molecular weight biothiols in umbilical cord whole blood.

    Science.gov (United States)

    Kuligowski, Julia; El-Zahry, Marwa R; Sánchez-Illana, Ángel; Quintás, Guillermo; Vento, Máximo; Lendl, Bernhard

    2016-04-07

    Biothiols play an essential role in a number of biological processes in living organisms including detoxification and metabolism. Fetal to neonatal transition poses a pro-oxidant threat for newborn infants, especially those born prematurely. A reliable and rapid tool for the direct determination of thiols in small volume whole blood (WB) samples would be desirable for its application in clinical practice. This study shows the feasibility of Surface Enhanced Raman Spectroscopy (SERS) using a silver colloid prepared by reduction of silver nitrate using hydroxylamine, as the SERS substrate for the quantification of thiols in WB samples after a simple precipitation step for protein removal. Bands originating from biothiols (790, 714 and 642 cm(-1)) were enhanced by the employed SERS substrate and the specificity of the detected SERS signal was tested for molecules presenting -SH functional groups. A statistically significant correlation between the obtained SERS signals and the thiol concentration measured using a chromatographic reference method in umbilical cord WB samples could be demonstrated. Using WB GSH concentrations obtained from the chromatographic reference procedure, a Partial Least Squares (PLS) regression model covering GSH concentrations from 13 to 2200 μM was calculated obtaining a root mean square error of prediction (RMSEP) of 381 μM when applied to an external test set. The developed approach uses small blood sample volumes (50 μL), which is important for clinical applications, especially in the field of neonatology. This feasibility study shows that the present approach combines all the necessary characteristics for its potential application in clinical practice.

  18. Sequence dependent DNA conformations: Raman spectroscopic studies and a model of action of restriction enzymes

    International Nuclear Information System (INIS)

    Nishimura, Y.

    1985-01-01

    Raman spectra have been examined to clarify the polymorphic forms of DNA, A, B, and Z forms. From an analysis the authors found that the guanine ring breathing vibration is sensitive to its local conformation. Examination of nine crystals of guanosine residues in which the local conformations are well established revealed that a guanosine residue with a C3'endo-anti gives a strong line at 666+-2 cm/sup -1/, O4'endo-anti at 682 cm/sup -1/, C1'exo-anti at 673 cm/sup -1/, C2'endo-anti at 677 cm/sup -1/ and syn-forms around 625 cm/sup -1/. Using this characteristic line, they were able to obtain the local conformations of guanosine moieties in poly(dG-dC). Such a sequence derived variation is suggested to be recognized by sequence specific proteins such as restriction enzymes. The authors found a correlation between sequence dependent DNA conformation and a mode of action of restriction enzymes. The cutting mode of restriction enzymes is classified into three groups. The classification of whether the products have blunt ends, two-base-long cohesive ends, or four-base-long cohesive ends depends primarily on the substrate, not on the enzyme. It is suggested that sequence dependent DNA conformation causes such a classification by the use of the Calladine-Dickerson analysis. In the recognition of restriction enzymes, the methyl group in a certain sequence is considered to play an important role by changing the local conformation of DNA

  19. Theory of Graphene Raman Scattering.

    Science.gov (United States)

    Heller, Eric J; Yang, Yuan; Kocia, Lucas; Chen, Wei; Fang, Shiang; Borunda, Mario; Kaxiras, Efthimios

    2016-02-23

    Raman scattering plays a key role in unraveling the quantum dynamics of graphene, perhaps the most promising material of recent times. It is crucial to correctly interpret the meaning of the spectra. It is therefore very surprising that the widely accepted understanding of Raman scattering, i.e., Kramers-Heisenberg-Dirac theory, has never been applied to graphene. Doing so here, a remarkable mechanism we term"transition sliding" is uncovered, explaining the uncommon brightness of overtones in graphene. Graphene's dispersive and fixed Raman bands, missing bands, defect density and laser frequency dependence of band intensities, widths of overtone bands, Stokes, anti-Stokes anomalies, and other known properties emerge simply and directly.

  20. Ultrafast surface-enhanced Raman spectroscopy.

    Science.gov (United States)

    Keller, Emily L; Brandt, Nathaniel C; Cassabaum, Alyssa A; Frontiera, Renee R

    2015-08-07

    Ultrafast surface-enhanced Raman spectroscopy (SERS) with pico- and femtosecond time resolution has the ability to elucidate the mechanisms by which plasmons mediate chemical reactions. Here we review three important technological advances in these new methodologies, and discuss their prospects for applications in areas including plasmon-induced chemistry and sensing at very low limits of detection. Surface enhancement, arising from plasmonic materials, has been successfully incorporated with stimulated Raman techniques such as femtosecond stimulated Raman spectroscopy (FSRS) and coherent anti-Stokes Raman spectroscopy (CARS). These techniques are capable of time-resolved measurement on the femtosecond and picosecond time scale and can be used to follow the dynamics of molecules reacting near plasmonic surfaces. We discuss the potential application of ultrafast SERS techniques to probe plasmon-mediated processes, such as H2 dissociation and solar steam production. Additionally, we discuss the possibilities for high sensitivity SERS sensing using these stimulated Raman spectroscopies.

  1. Spectroscopic (NMR, UV, FT-IR and FT-Raman) analysis and theoretical investigation of nicotinamide N-oxide with density functional theory.

    Science.gov (United States)

    Atac, Ahmet; Karabacak, Mehmet; Kose, Etem; Karaca, Caglar

    2011-12-01

    The spectroscopic properties of the nicotinamide N-oxide (abbreviated as NANO, C(6)H(6)N(2)O(2)) were examined by FT-IR, FT-Raman, NMR and UV techniques. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. The (1)H and (13)C NMR spectra were recorded in DMSO. The UV absorption spectrum of the compound that dissolved in water was recorded in the range of 200-800 nm. The structural and spectroscopic data of the molecule in the ground state were calculated by using Density Functional Theory (DFT) employing B3LYP methods with the 6-311++G(d,p) basis set. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The optimized structure of compound was interpreted and compared with the reported experimental values. The observed vibrational wavenumbers, absorption wavelengths and chemical shifts were compared with calculated values. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Diffusion Raman et luminescence dans des aerogels de silice purs ou dopes Dy

    Science.gov (United States)

    Guerri, F.; Fabre, F.; Zwick, A.; Bournett, D.

    1994-02-01

    Light scattering studies of pure and Dy doped aerogels are presented. Careful examination of Stokes and anti-Stokes spectra allow the discrimination between Raman and luminescence processes. It is shown that in pure aerogels, scattered intensity is due to Raman processes only, and the density of vibrational states does not exhibit any singularity. The fractal properties of the structure imply modifications not only in the spectral distribution of the low frequency modes (usually labelled phonons and fractons) but alsoin the high frequency one, at least up to 600 cm-1. In Dy-doped dense silica, coupling between electronic and vibronic excitations is evidenced by the presence of anti-Stokes luminescence. In Dy-doped aerogels, the enlarged Dy3+ electronic levels, strongly coupled with vibrational states give rise to emission processes traducing the response of the sample as a whole, rather than resonant Raman scattering or luminescence processes.

  3. Raman spectroscopic analysis of the carotenoid concentration in egg yolks depending on the feeding and housing conditions of the laying hens.

    Science.gov (United States)

    Hesterberg, Karoline; Schanzer, Sabine; Patzelt, Alexa; Sterry, Wolfram; Fluhr, Joachim W; Meinke, Martina C; Lademann, Jürgen; Darvin, Maxim E

    2012-01-01

    Resonance Raman spectroscopic measurements are suited to analyze the concentration of carotenoid antioxidants in biological samples. Previously, it has been shown that the carotenoid concentration of nutritional egg yolks has a direct influence on the carotenoid content of human skin in vivo. In the present study, resonance Raman spectroscopy was used to analyze the carotenoid concentration in the yolks of hen eggs, which were housed in battery cages or alternatively on free-range grassland. The egg yolks of hens, which had access to grassland, contained approximately double the amount of carotenoid concentration than the egg yolks of hens housed in battery cages (p egg yolks, depending on fodder, housing and weather conditions, were investigated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Micro-Raman spectroscopic studies on the adhesive-dentine interface and the degree of conversion of dental adhesives

    OpenAIRE

    Miletic, Vesna

    2010-01-01

    A series of studies on monomer to polymer conversion in adhesive systems was undertaken using micro-Raman spectroscopy. A database of micro-Raman spectra was compiled for identification of tooth tissues and materials. The degree of conversion was assessed as a function of time and light source. Linear and two-dimensional micro- Raman characterisations of the adhesive-dentine and resin-based composite-adhesivedentine interfaces were performed. The degree of monomer to polymer co...

  5. Broadband Fiber Raman Power-Amplifier for Narrow Linewidth Tunable Seed Lasers Used in Spectroscopic Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an energy and space efficient high power continuous wave (cw) narrow linewidth broadband fiber Raman amplifier (FRA) with spectrally tunable...

  6. FTIR, Raman, and UV-Vis spectroscopic and DFT investigations of the structure of iron-lead-tellurate glasses.

    Science.gov (United States)

    Rada, Simona; Dehelean, Adriana; Culea, Eugen

    2011-08-01

    In this work, the effects of iron ion intercalations on lead-tellurate glasses were investigated via FTIR, Raman and UV-Vis spectroscopies. This homogeneous glass system has compositions xFe(2)O(3)·(100-x)[4TeO(2)·PbO(2)], where x = 0-60 mol%. The presented observations in these mechanisms show that the lead ions have a pronounced affinity towards [TeO(3)] structural units, resulting in the deformation of the Te-O-Te linkages, and leading to the intercalation of [PbO( n )] (n = 3, 4) and [FeO( n )] (n = 4, 6) entities in the [TeO(4)] chain network. The formation of negatively charged [FeO(4)](1-) structural units implies the attraction of Pb(2+) ions in order to compensate for this electrical charge. Upon increasing the Fe(2)O(3) content to 60 mol%, the network can accommodate an excess of oxygen through the formation of [FeO(6)] structural units and the conversion of [TeO(4)] into [TeO(3)] structural units. For even higher Fe(2)O(3) contents, Raman spectra indicate a greater degree of depolymerization of the vitreous network than FTIR spectra do. The bands due to the Pb-O bond vibrations are very strongly polarized and the [TeO(4)] structural units convert into [TeO(3)] units via an intermediate coordination stage termed "[TeO(3+1)]" structural units. Our UV-Vis spectroscopic data show two mechanisms: (i) the conversion of the Fe(3+) to Fe(2+) at the same time as the oxidation of Pb(2+) to Pb(+4) ions for samples with low Fe(2)O(3) contents; (ii) when the Fe(2)O(3) content is high (x ≥ 50 mol%), the Fe(2+) ions capture positive holes and are transferred to Fe(3+) ions through a photochemical reaction, while the Pb(2+) ions are formed by the reduction of Pb(4+) ions. DFT calculations show that the addition of Fe(2)O(3) to lead-tellurate glasses seems to break the axial Te-O bonds, and the [TeO(4)] structural units are gradually transformed into [TeO(3+1)]- and [TeO(3)]-type polyhedra. Analyzing these data further indicates a gradual

  7. In Situ Raman Spectroscopic Study of Barite as a Pressure Gauge Using a Hydrothermal Diamond Anvil Cell.

    Science.gov (United States)

    Liu, Chuanjiang; Wang, Duojun; Zheng, Haifei

    2016-02-01

    In situ Raman measurements of barite were performed at temperatures in the range of 298-673 K and pressures in the range of 105-1217 MPa using a hydrothermal diamond anvil cell combined with laser Raman spectroscopy. The Raman frequency and the full width at half maximum (FWHM) of the most intense ν1 Raman peak for barite as a function of pressure and temperature were obtained. In the experimental P-T ranges, the ν1Raman band systematically shifted toward low wavenumbers with increasing pressure and temperature. The positive pressure dependence of ν1Raman frequency indicates stress-induced shortening of the S-O bond, whereas the negative temperature dependence shows temperature-induced expansion of the S-O bond. In contrast, the observed ν1Raman band became broadened, which should be attributed to the reduced ordering of molecular structure. Based on the obtained data, the established relationships among the Raman shift or the FWHM, pressure and temperature can be used to obtain good estimates of the internal pressure in natural barite-bearing fluid inclusions or hydrothermal diamond anvil cell. This is a sensitive and reliable approach to the accurate determination of geological pressure. © The Author(s) 2015.

  8. Will Raman meet bacteria on Mars? An overview of the optimal Raman spectroscopic techniques for carotenoid biomarkers detection on mineral backgrounds

    NARCIS (Netherlands)

    Hooijschuur, J.H.; Verkaaik, M.F.C.; Davies, G.R.; Ariese, F.

    2016-01-01

    Raman spectroscopy appears to be an ideal technique for the initial detection of biomarkers, molecules that are potentially indicative of life on planetary bodies elsewhere in our solar system. Carotenoids are particularly useful biomarkers as they are used widely across the species, relatively

  9. Raman spectroscopic analysis of cyanogenic glucosides in plants: development of a Flow Injection Surface-Enhanced Raman Scatter (FI-SERS) method for determination of cyanide

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; Jørgensen, Kirsten; Møller, Birger Lindberg

    2004-01-01

    -dried sorghum leaf was also obtained using this instrument. Surface-enhanced Raman Spectroscopy (SERS) was demonstrated to be a more sensitive method that enabled determination of the cyanogenic potential of plant tissue. The SERS method was optimized by flow injection (FI) using a colloidal gold dispersion...... as effluent. Potential problems and pitfalls of the method are discussed....

  10. Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Hassan Refat H. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom); Edwards, Howell G.M. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)], E-mail: H.G.M.Edwards@bradford.ac.uk; Hargreaves, Michael D.; Munshi, Tasnim; Scowen, Ian J.; Telford, Richard J. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)

    2008-07-14

    Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting {beta}-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488-1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectroscopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control.

  11. Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Ali, Hassan Refat H.; Edwards, Howell G.M.; Hargreaves, Michael D.; Munshi, Tasnim; Scowen, Ian J.; Telford, Richard J.

    2008-01-01

    Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting β-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488-1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectroscopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control

  12. Automatic and objective oral cancer diagnosis by Raman spectroscopic detection of keratin with multivariate curve resolution analysis

    Science.gov (United States)

    Chen, Po-Hsiung; Shimada, Rintaro; Yabumoto, Sohshi; Okajima, Hajime; Ando, Masahiro; Chang, Chiou-Tzu; Lee, Li-Tzu; Wong, Yong-Kie; Chiou, Arthur; Hamaguchi, Hiro-O.

    2016-01-01

    We have developed an automatic and objective method for detecting human oral squamous cell carcinoma (OSCC) tissues with Raman microspectroscopy. We measure 196 independent Raman spectra from 196 different points of one oral tissue sample and globally analyze these spectra using a Multivariate Curve Resolution (MCR) analysis. Discrimination of OSCC tissues is automatically and objectively made by spectral matching comparison of the MCR decomposed Raman spectra and the standard Raman spectrum of keratin, a well-established molecular marker of OSCC. We use a total of 24 tissue samples, 10 OSCC and 10 normal tissues from the same 10 patients, 3 OSCC and 1 normal tissues from different patients. Following the newly developed protocol presented here, we have been able to detect OSCC tissues with 77 to 92% sensitivity (depending on how to define positivity) and 100% specificity. The present approach lends itself to a reliable clinical diagnosis of OSCC substantiated by the “molecular fingerprint” of keratin.

  13. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    OpenAIRE

    Shahabi, Sima; Fekrazad, Reza; Johari, Maryam; Chiniforoush, Nasim; Rezaei, Yashar

    2016-01-01

    Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-cariou...

  14. Raman spectroscopic features of Al- Fe3+- poor magnesiochromite and Fe2+- Fe3+- rich ferrian chromite solid solutions

    Science.gov (United States)

    Kharbish, Sherif

    2017-08-01

    Naturally occurring Al- Fe3 +- poor magnesiochromite and Fe2+- Fe3 +- rich ferrian chromite solid solutions have been analyzed by micro-Raman spectroscopy. The results reflect a strong positive correlation between the Fe3 + # [Fe3+/(Fe3 ++Cr + Al)] and the positions of all Raman bands. A positive correlation of the Raman band positions with Mg# [Mg/(Mg + Fe2 +)] is less stringent. Raman spectra of magnesiochromite and ferrian chromite show seven and six bands, respectively, in the spectral region of 800 - 100 cm- 1. The most intense band in both minerals is identified as symmetric stretching vibrational mode, ν 1(A 1g ). In the intermediate Raman-shift region (400-600 cm- 1), the significant bands are attributed to the ν 3(F 2g ) > ν 4(F 2g ) > ν 2(E g ) modes. The bands with the lowest Raman shifts (< 200 cm- 1) are assigned to F 2g (trans) translatory lattice modes. Extra bands in magnesiochromite (two bands) and in ferrian chromite (one weak band) are attributed to lowering in local symmetry and order/disorder effects.

  15. The intermediate frequency modes of single- and double-walled carbon nanotubes: a Raman spectroscopic and in situ Raman spectroelectrochemical study.

    Science.gov (United States)

    Kalbac, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, Lothar

    2006-05-24

    The intermediate frequency modes (IFM) of single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were analyzed by Raman spectroscopy and in situ Raman spectroelectrochemistry. The inner and outer tubes of DWCNTs manifested themselves as distinct bands in the IFM region. This confirmed the diameter dependence of IFM frequencies. Furthermore, the analysis of inner tubes of DWCNTs allowed a more-precise assignment of the bands in the IFM region to features intrinsic for carbon nanotubes. Although the inner tubes in DWCNTs are assumed to be structurally perfect, the role of defects on IFM was discussed. The dependence of IFM on electrochemical charging was also studied. In situ spectroelectrochemical data provide a means to distinguish the bands of the outer and inner tubes.

  16. The joined use of n.i. spectroscopic analyses - FTIR, Raman, visible reflectance spectrometry and EDXRF - to study drawings and illuminated manuscripts

    Energy Technology Data Exchange (ETDEWEB)

    Bruni, S.; Guglielmi, V. [Universita degli Studi di Milano, Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Milano (Italy); Caglio, S. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); Poldi, G. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); LAM, Universita degli Studi di Bergamo, Bergamo (Italy)

    2008-07-15

    Some art objects being small and very precious prevents conservators and conservation scientists from whatever kind of sampling, so that only completely non-invasive (n.i.) studies are permitted. Besides, also moving the object is sometimes forbidden: this happens for jewels as well as for manuscripts, illuminated codices, drawings and paintings. Some important physical n.i. analyses, such as PIXE and PIGE, therefore cannot be used in many cases. With these limitations, only imaging techniques in X, UV, Visible and IR bands, and a few spectroscopic methods that can be carried out with portable instruments can be applied, i.e. molecular spectroscopies like Fourier transform infrared (FTIR), Raman, UV visible and near IR reflectance spectrometry (UV-Vis-NIR RS) and atomic spectroscopy like energy dispersive X-ray fluorescence (EDXRF). The use of only one or two of these techniques is usually far from giving all the information required to achieve a full characterization of materials used by the artist or during restorations, and to understand some conservative problems of the object. On the contrary, a joined use of n.i. analyses can supply a larger set of data, allowing for cross checks. With this aim we show a fully integrated spectroscopic approach to polychrome objects, and, in particular, to drawings and illuminated manuscripts, using portable instruments, specifically {mu}-FTIR, {mu}-Raman, Vis-RS and EDXRF, where also the Raman signal does not suffer fluorescence caused by varnish coating and from binder. We propose the joined use of all these four physical analyses to characterize materials - support, pigments, dyes, binders, etc. - on a complex case: a painted and drawn parchment of the late 15th century, or the beginning of the 16th, partly attributed to Andrea Mantegna. The collected spectroscopic data have been compared to proper spectral databases, some of which specifically realized in our laboratories. Also, mixtures of pigments and their

  17. Raman and Surface Enhanced Raman of Biological Material

    National Research Council Canada - National Science Library

    Guicheteau, Jason A; Gonser, Kristina; Christesen, Steven Dale

    2004-01-01

    .... Vibrational spectroscopic methods such as Raman and surface enhanced Raman scattering (SERS) provide rapid detailed fingerprint information about the molecular composition of biomaterial in a non-destructive manner...

  18. Measuring changes in chemistry, composition, and molecular structure within hair fibers by infrared and Raman spectroscopic imaging

    Science.gov (United States)

    Zhang, Guojin; Senak, Laurence; Moore, David J.

    2011-05-01

    Spatially resolved infrared (IR) and Raman images are acquired from human hair cross sections or intact hair fibers. The full informational content of these spectra are spatially correlated to hair chemistry, anatomy, and structural organization through univariate and multivariate data analysis. Specific IR and Raman images from untreated human hair describing the spatial dependence of lipid and protein distribution, protein secondary structure, lipid chain conformational order, and distribution of disulfide cross-links in hair protein are presented in this study. Factor analysis of the image plane acquired with IR microscopy in hair sections, permits delineation of specific micro-regions within the hair. These data indicate that both IR and Raman imaging of molecular structural changes in a specific region of hair will prove to be valuable tools in the understanding of hair structure, physiology, and the effect of various stresses upon its integrity.

  19. Applications of coherent Raman scattering microscopies to clinical and biological studies.

    Science.gov (United States)

    Schie, Iwan W; Krafft, Christoph; Popp, Jürgen

    2015-06-21

    Coherent anti-Stokes Raman scattering (CARS) microscopy and stimulated Raman scattering (SRS) microscopy are two nonlinear optical imaging modalities that are at the frontier of label-free and chemical specific biological and clinical diagnostics. The applications of coherent Raman scattering (CRS) microscopies are multifold, ranging from investigation of basic aspects of cell biology to the label-free detection of pathologies. This review summarizes recent progress of biological and clinical applications of CRS between 2008 and 2014, covering applications such as lipid droplet research, single cell analysis, tissue imaging and multiphoton histopathology of atherosclerosis, myelin sheaths, skin, hair, pharmaceutics, and cancer and surgical margin detection.

  20. In-situ plasmon-driven chemical reactions revealed by high vacuum tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Sun, Mengtao; Zhang, Zhenglong; Zheng, Hairong; Xu, Hongxing

    2012-01-01

    With strong surface plasmons excited at the metallic tip, tip-enhanced Raman spectroscopy (TERS) has both high spectroscopic sensitivity and high spatial resolution, and is becoming an essential tool for chemical analysis. It is a great challenge to combine TERS with a high vacuum system due to the poor optical collection efficiency. We used our innovatively designed home-built high vacuum TERS (HV-TERS) to investigate the plasmon-driven in-situ chemical reaction of 4-nitrobenzenethiol dimerizing to dimercaptoazobenzene. The chemical reactions can be controlled by the plasmon intensity, which in turn can be controlled by the incident laser intensity, tunneling current and bias voltage. The temperature of such a chemical reaction can also be obtained by the clearly observed Stokes and Anti-Stokes HV-TERS peaks. Our findings offer a new way to design a highly efficient HV-TERS system and its applications to chemical catalysis and synthesis of molecules, and significantly extend the studies of chemical reactions.

  1. Deep-UV Raman spectroscopic analysis of structure and dissolution rates of silica-rich sodium borosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Eric M [ORNL; WindischJr., Charles F. [Pacific Northwest National Laboratory (PNNL); Burton, Sarah D. [Pacific Northwest National Laboratory (PNNL); Bovaird, Chase C. [Pacific Northwest National Laboratory (PNNL)

    2010-01-01

    As part of ongoing studies to evaluate relationships between structure and rates of dissolution of silicate glasses in aqueous media, sodium borosilicate glasses of composition Na2O xB2O3 (3 x)SiO2, with x 1 (Na2O/B2O3 ratio 1), were analyzed using deep-UV Raman spectroscopy. Results were quantified in terms of the fraction of SiO4 tetrahedra with one non-bridging oxygen (Q3) and then correlated with Na2O and B2O3 content. The Q3 fractionwas found to increase with increasing Na2O content, in agreement with studies on related glasses, and, as long as the value of x was not too high, this contributed to higher rates of dissolution in single pass flow-through testing. In contrast, dissolution rates were less strongly determined by the Q3 fraction when the value of x was near unity, and appeared to grow larger upon further reduction of the Q3 fraction. Results were interpreted to indicate the increasingly important role of network hydrolysis in the glass dissolution mechanism as the BO4 tetrahedron replaces the Q3 unit as the charge-compensating structure for Na+ ions. Finally, the use of deep-UV Raman spectroscopy was found to be advantageous in studying finely powdered glasses in cases where visible Raman spectroscopy suffered from weak Raman scattering and fluorescence interference.

  2. Surface-enhanced Raman spectroscopic studies of the Au-pentacene interface: a combined experimental and theoretical investigation.

    Science.gov (United States)

    Adil, D; Guha, S

    2013-07-28

    It has recently been shown [D. Adil and S. Guha, J. Phys. Chem. C 116, 12779 (2012)] that a large enhancement in the Raman intensity due to surface-enhanced Raman scattering (SERS) is observed from pentacene when probed through the Au contact in organic field-effect transistors (OFET) structures. Here, the SERS spectrum is shown to exhibit a high sensitivity to disorder introduced in the pentacene film by Au atoms. The Raman signature of the metal-semiconductor interface in pentacene OFETs is calculated with density-functional theory by explicitly considering the Au-pentacene interaction. The observed enhancement in the 1380 cm(-1) and the 1560 cm(-1) regions of the experimental Raman spectrum of pentacene is successfully modeled by Au-pentacene complexes, giving insights into the nature of disorder in the pentacene sp(2) network. Finally, we extend our previous work on high-operating voltage pentacene OFETs to low-operating voltage pentacene OFETs. No changes in the SERS spectra before and after subjecting the OFETs to a bias stress are observed, concurrent with no degradation in the threshold voltage. This shows that bias stress induced performance degradation is, in part, caused by field-induced structural changes in the pentacene molecule. Thus, we confirm that the SERS spectrum can be used as a visualization tool for correlating transport properties to structural changes, if any, in organic semiconductor based devices.

  3. Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

    Directory of Open Access Journals (Sweden)

    Myeongsu Seong

    2017-01-01

    Full Text Available The cancer field effect (CFE has been highlighted as one of indirect indications for tissue variations that are insensitive to conventional diagnostic techniques. In this research, we had a hypothesis that chemotherapy for breast cancer would affect skin biochemical compositions that would be reflected by Raman spectral changes. We used a fiber-optic probe-based Raman spectroscopy to perform preliminary animal experiments to validate the hypothesis. Firstly, we verified the probing depth of the fiber-optic probe (~800 μm using a simple intravenous fat emulsion-filled phantom having a silicon wafer at the bottom inside a cuvette. Then, we obtained Raman spectra during breast cancer treatment by chemotherapy from a small animal model in longitudinal manner. Our results showed that the treatment causes variations of biochemical compositions in the skin. For further validation, the Raman spectra will have to be collected from more populations and spectra will need to be compared with immunohistochemistry of the breast tissue.

  4. Surface-enhanced Raman spectroscopic study of DNA and 6-mercapto-1-hexanol interactions using large area mapping

    DEFF Research Database (Denmark)

    Frøhling, Kasper Bayer; Alstrøm, Tommy Sonne; Bache, Michael

    2016-01-01

    intensities and peak positions it is possible to directly inspect the interplay between DNA and 6-mercapto-1-hexanol on gold covered nanopillars. It is demonstrated that optimised functionalization parameters can be extracted from the Raman spectra directly. Using the peak-fitting approach it is possible...

  5. Development and comparative assessment of Raman spectroscopic classification algorithms for lesion discrimination in stereotactic breast biopsies with microcalcifications

    Science.gov (United States)

    Dingari, Narahara Chari; Barman, Ishan; Saha, Anushree; McGee, Sasha; Galindo, Luis H.; Liu, Wendy; Plecha, Donna; Klein, Nina; Dasari, Ramachandra Rao; Fitzmaurice, Maryann

    2014-01-01

    Microcalcifications are an early mammographic sign of breast cancer and a target for stereotactic breast needle biopsy. Here, we develop and compare different approaches for developing Raman classification algorithms to diagnose invasive and in situ breast cancer, fibrocystic change and fibroadenoma that can be associated with microcalcifications. In this study, Raman spectra were acquired from tissue cores obtained from fresh breast biopsies and analyzed using a constituent-based breast model. Diagnostic algorithms based on the breast model fit coefficients were devised using logistic regression, C4.5 decision tree classification, k-nearest neighbor (k-NN) and support vector machine (SVM) analysis, and subjected to leave-one-out cross validation. The best performing algorithm was based on SVM analysis (with radial basis function), which yielded a positive predictive value of 100% and negative predictive value of 96% for cancer diagnosis. Importantly, these results demonstrate that Raman spectroscopy provides adequate diagnostic information for lesion discrimination even in the presence of microcalcifications, which to the best of our knowledge has not been previously reported. Raman spectroscopy and multivariate classification provide accurate discrimination among lesions in stereotactic breast biopsies, irrespective of microcalcification status. PMID:22815240

  6. Surface-enhanced Raman spectroscopic studies of the Au-pentacene interface: A combined experimental and theoretical investigation

    Science.gov (United States)

    Adil, D.; Guha, S.

    2013-07-01

    It has recently been shown [D. Adil and S. Guha, J. Phys. Chem. C 116, 12779 (2012)], 10.1021/jp3031804 that a large enhancement in the Raman intensity due to surface-enhanced Raman scattering (SERS) is observed from pentacene when probed through the Au contact in organic field-effect transistors (OFET) structures. Here, the SERS spectrum is shown to exhibit a high sensitivity to disorder introduced in the pentacene film by Au atoms. The Raman signature of the metal-semiconductor interface in pentacene OFETs is calculated with density-functional theory by explicitly considering the Au-pentacene interaction. The observed enhancement in the 1380 cm-1 and the 1560 cm-1 regions of the experimental Raman spectrum of pentacene is successfully modeled by Au-pentacene complexes, giving insights into the nature of disorder in the pentacene sp2 network. Finally, we extend our previous work on high-operating voltage pentacene OFETs to low-operating voltage pentacene OFETs. No changes in the SERS spectra before and after subjecting the OFETs to a bias stress are observed, concurrent with no degradation in the threshold voltage. This shows that bias stress induced performance degradation is, in part, caused by field-induced structural changes in the pentacene molecule. Thus, we confirm that the SERS spectrum can be used as a visualization tool for correlating transport properties to structural changes, if any, in organic semiconductor based devices.

  7. Raman Spectroscopic Analysis of Biochemical Changes in Individual Triglyceride-Rich Lipoproteins in the Pre- and Postprandial State

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J; Motton, D; Rutledge, J; Keim, N; Huser, T

    2004-09-13

    Individual triglyceride-rich lipoprotein (TGRL) particles derived from human volunteers are non-destructively analyzed by laser tweezers Raman microspectroscopy and information on their composition and distribution is obtained. The Raman signature of single optically trapped very low-density lipoproteins (VLDL), a subclass of TGRL, which play an important role in cardiovascular disease, exhibits distinct peaks associated with molecular vibrations of fatty acids, proteins, lipids, and structural rearrangements of lipids. Our analysis of pre- and postprandial VLDL exhibits the signature of biochemical changes in individual lipoprotein particles following the consumption of meals. Interaction of VLDL with endothelium leads to the breakdown of complex triacylglycerols and the formation of a highly ordered core of free saturated fatty acids in the particle. A particle distribution analysis reveals trends in the degree to which this process has occurred in particles at different times during the postprandial period. Differences in particle distributions based on the different ratios of polyunsaturated to saturated fats in the consumed meals are also easily discerned. Individual lipoprotein particles hydrolyzed in-vitro through addition of lipoprotein lipase (LpL) exhibit strikingly similar changes in their Raman spectra. These results demonstrate the feasibility of monitoring the dynamics of lipid metabolism of individual TGRL particles as they interact with LpL in the endothelial cell wall using Raman spectroscopy.

  8. Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings.

    Science.gov (United States)

    García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

    2016-12-13

    Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'. © 2016 The Author(s).

  9. CARS (Coherent Anti-Stokes Raman Scattering) Spectroscopy of the Reaction Zone of Methane-Nitrous Oxide and RDX Propellant Flames.

    Science.gov (United States)

    1986-01-01

    mospheric pressure--perhaps due to the adsorption by NO2 in the region of the laser beams used in these experiments. Additional experiments are needed (laser...Engineering * ATTN: S. Temkin University Heights Campus New Brunswick, NJ 08903 SRI International ATTN: Technical Library * D. Crosley J. Barker D. Golden G

  10. Pigment analyses of a portrait and paint box of Turkish artist Feyhaman Duran (1886-1970): The EDXRF, FT-IR and micro Raman spectroscopic studies

    Science.gov (United States)

    Akyuz, Sevim; Akyuz, Tanil; Emre, Gulder; Gulec, Ahmet; Basaran, Sait

    2012-04-01

    The samples obtained from nine different places of Ataturk portrait (oil on canvas, 86 cm × 136 cm) by Feyhaman Duran (1886-1970), one of the famous Turkish painters of the 20th century, together with five pigment samples (two different white, two different yellow and blue), obtained as powders from artist's paint box, were analysed by EDXRF, FT-IR and micro-Raman spectroscopic methods, in order to characterise the pigments used by the artist. Informative Raman signals were not obtained from most of the samples of the portrait, due to huge fluorescence caused by the presence of impurities and organic materials in the samples, however the Raman spectrum of the sample from skin coloured part of the portrait and the pigment samples obtained from the paint box of the artist were found to be very informative to shed light on the determination of the pigments used. Analysis revealed the presences of chrome yellow (PbCrO4), strontium yellow (SrCrO4) and Cadmium yellow (CdS) as yellow, chromium oxides (Cr2O3 and Cr2O3·2H2O) as green, natural red ochre as red, brown ochre as brown and ivory black or bone black (C + Ca3(PO4)2) and manganese oxides (Mn2O3 and MnO2) as black pigments, in the composition of the Ataturk portrait. Lead white (2PbCO3·Pb(OH)2), calcite (CaCO3), barite (BaSO4), zinc white (ZnO) and titanium white (TiO2) were used as extenders to lighten the colours and/or as for ground level painting. Powder pigment samples, obtained from the paint box of artist, were found to be mixed pigments rather than pure ones.

  11. Raman Spectroscopic Analysis of Fingernail Clippings Can Help Differentiate between Postmenopausal Women who Have and Have Not Suffered a Fracture

    Directory of Open Access Journals (Sweden)

    James R. Beattie

    2016-01-01

    Full Text Available Raman spectroscopy was applied to nail clippings from 633 postmenopausal British and Irish women, from six clinical sites, of whom 42% had experienced a fragility fracture. The objective was to build a prediction algorithm for fracture using data from four sites (known as the calibration set and test its performance using data from the other two sites (known as the validation set. Results from the validation set showed that a novel algorithm, combining spectroscopy data with clinical data, provided area under the curve (AUC of 74% compared to an AUC of 60% from a reduced QFracture score (a clinically accepted risk calculator and 61% from the dual-energy X-ray absorptiometry T -score, which is in current use for the diagnosis of osteoporosis. Raman spectroscopy should be investigated further as a noninvasive tool for the early detection of enhanced risk of fragility fracture.

  12. Surface-enhanced Raman spectroscopic analysis of phorate and fenthion pesticide in apple skin using silver nanoparticles.

    Science.gov (United States)

    Li, Xiaozhou; Zhang, Su; Yu, Zhuang; Yang, Tianyue

    2014-01-01

    Traditional pesticide residue detection methods are usually complicated, time consuming, and expensive. Rapid, portable, online, and real-time detection kits are the developing direction of pesticide testing. In this paper, we used a surface-enhanced Raman spectroscopy (SERS) technique to detect the organophosphate pesticide residue of phorate and fenthion in apple skin, for the purpose of finding a fast, simple, and convenient detection method for pesticide detection. The results showed that the characteristic wavenumbers of the two organophosphorus pesticides are more easily identified using SERS. We selected the Raman peaks at 728 cm(-1) of phorate and 1215 cm(-1) of fenthion as the target peaks for quantitative analysis, and utilized internal standards to establish linear regression models for phorate and fenthion. The detection limit was 0.05 mg/L for phorate and 0.4 mg/L for fenthion. This method can be used as a quantitative analytical reference for the detection of phorate and fenthion.

  13. Deep-UV Raman spectroscopic analysis of structure and dissolution rates of silica-rich sodium borosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Pierce, Eric M.; Burton, Sarah D.; Bovaird, Chase C.

    2011-03-24

    As part of ongoing studies to evaluate the relationships between structural variations in silicate glasses and rates of glass dissolution in aqueous media, molecular structures present in sodium borosilicate glasses of composition Na2O.xB2O3.(3-x)SiO2, with x 1 (Na2O/B2O3 ratio 1), were analyzed using deep-UV Raman spectroscopy. The results were quantified in terms of the fraction of SiO4 tetrahedra with one non-bridging oxygen (Q3) and then correlated with Na2O and B2O3 content. Increasing Na2O was found to raise the fraction of Q3 units in the glasses systematically, in agreement with studies on related glasses, and, as long as the value of x was not too high, contribute to higher rates of dissolution in single pass flow-through testing. The finding was obtained across more than one series of silica-rich glasses prepared for independent dissolution studies. In contrast, dissolution rates were less strongly determined by the Q3 fraction when the value of x was near unity and appeared to grow larger upon further reduction of the Q3 fraction. The results were interpreted to indicate the increasingly important role of network hydrolysis in the glass dissolution mechanism as the BO4 tetrahedron replaces the Q3 unit as the charge-compensating structure for Na+ ions. Finally, the use of deep-UV Raman spectroscopy was found to be advantageous in studying finely powdered glasses in cases where visible Raman spectroscopy suffered from weak Raman scattering and fluorescence interference.

  14. Infrared, Raman and Magnetic Resonance Spectroscopic study of SiO.sub.2./sub.:C nanopowders

    Czech Academy of Sciences Publication Activity Database

    Savchenko, Dariia; Vorlíček, Vladimír; Kalabukhova, E.; Sitnikov, A.; Vasin, A.; Kysil, D.; Sevostianov, S.; Tertykh, V.; Nazarov, A.

    2017-01-01

    Roč. 12, č. 1 (2017), 1-12, č. článku 292. ISSN 1931-7573 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : EPR * Raman spectroscopy * carbosil * carbon nanodots * carbon-related defects Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.)

  15. Raman spectroscopic investigation of the effects of cosmetic formulations on the constituents and properties of human skin.

    Science.gov (United States)

    Tosato, Maira G; Alves, Rani S; Dos Santos, Edson A P; Raniero, Leandro; Menezes, Priscila F C; Belletti, Klésia M S; Praes, Carlos Eduardo O; Martin, Airton A

    2012-02-01

    This study aimed to investigate the biochemical alterations in hydration and skin proteins, which are associated with the skin aging process, caused by cosmetic use. Many techniques have been used to assess the effectiveness of cosmetics' hydrating and anti-aging effects on skin. Recently, Raman spectroscopy has been shown to be a powerful, noninvasive tool that can monitor changes in the biomolecules of the skin in real time. Were analyzed human skin in vivo at the beginning of the experiment (T0) and after 30 (T30) and 60 (T60) days of continuous use of a cosmetic product. Fourier-transform and dispersive Raman spectroscopy were the used to examine the periorbicular right lateral eye region of 16 female Brazilian volunteers, aged 60-75 years. Multivariate statistical analysis of principal components analysis (PCA) and linear discriminant analysis were performed on all Raman spectra. Using the cosmetic product for 30 days increased the intensity of the Raman bands for collagen, amide III (1250-1350 cm(-1)) for proteins, and the water (OH) stretching mode at 3250 cm(-1), suggesting that the treatment was effective. The changes observed at T30 were not sustained at the same intensity for 60 days. Intensity variations in other bands may be related to changes in the organization of the epidermis at the dermal matrix. The application of cosmetics with active moisturizing and anti-aging properties helps to maintain the skin's protective barrier and to slow the intrinsic and extrinsic aging processes of the skin.

  16. Raman spectroscopic study of the aging and nitration of actinide processing anion-exchange resins in concentrated nitric acid

    International Nuclear Information System (INIS)

    Buscher, C. T.; Donohoe, R. J.; Mecklenburg, S. L.; Berg, J. M.; Tait, C. D.; Huchton, K. M.; Morris, D. E.

    1999-01-01

    Degradation of two types of anion exchange resins, Dowex 11 and Reillex HPQ, from the action of concentrated nitric acid (4 to 12 M) and radiolysis [from depleted uranium as UO 2 2+ nitrate species and 239 Pu as Pu(IV) nitrate species] was followed as a function of time with Raman vibrational spectroscopy. Elevated temperatures (∼50 degree sign C) were used in the absence of actinide metal loading to simulate longer exposures of the resin to a HNO 3 process stream and waste storage conditions. In the absence of actinide loading, only minor changes in the Dowex resin at acid concentrations ≤10 M were observed, while at 12 M acid concentration, the emergence of a Raman peak at 1345 cm-1 indicates the addition of nitro functional groups to the resin. Similar studies with the Reillex resin show it to be more resistant to nitric acid attack at all acid concentrations. Incorporation of weakly radioactive depleted uranium as the UO 2 2+ nitrate species to the ion-exchange sites of Dowex 11 under differing nitric acid concentrations (6 to 12 M) at room temperature showed no Raman evidence of resin degradation or nitration, even after several hundred days of contact. In contrast, Raman spectra for Dowex 11 in the presence of 239 Pu as Pu(IV) nitrate species reveal numerous changes indicating resin alterations, including a new mode at 1345 cm-1 consistent with a Pu(IV)-nitrate catalyzed addition of nitro groups to the resin backbone. (c) 2000 Society for Applied Spectroscopy

  17. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2016-12-01

    Full Text Available Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group; Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm–1 exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm-1 area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention.

  18. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers.

    Science.gov (United States)

    Shahabi, Sima; Fekrazad, Reza; Johari, Maryam; Chiniforoush, Nasim; Rezaei, Yashar

    2016-01-01

    Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group); Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm -1 ) exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm -1 ) area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention.

  19. Raman spectroscopic analysis of oral squamous cell carcinoma and oral dysplasia in the high-wavenumber region

    Science.gov (United States)

    Carvalho, Luis Felipe C. S.; Bonnier, Franck; O'Callaghan, Kate; O'Sullivan, Jeff; Flint, Stephen; Neto, Lazaro P. M.; Soto, Cláudio A. T.; dos Santos, Laurita; Martin, Airton A.; Byrne, Hugh J.; Lyng, Fiona M.

    2015-06-01

    Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with excellent spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1,800 cm-1) has been shown to be very promising for optical biopsy purposes. However, limitations to discrimination of dysplastic and inflammatory processes based on the fingerprint region still persist. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2,800-3,600 cm-1) provides more specific information based on N-H, O-H and C-H vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the highwavenumber spectral region by collecting Raman spectra of nucleoli, nucleus and cytoplasm from oral epithelial cancer (SCC-4) and dysplastic (DOK) cell lines and from normal oral epithelial primary cells, in vitro, which were then analyzed by area under the curve as a method to discriminate the spectra. In this region, we will show the discriminatory potential of the CH vibrational modes of nucleic acids, proteins and lipids. This technique demonstrated more efficient discrimination than the fingerprint region when we compared the cell cultures.

  20. Single pulse vibrational Raman scattering by a broadband KrF excimer laser in a hydrogen-air flame

    Science.gov (United States)

    Pitz, Robert W.; Wehrmeyer, Joseph A.; Bowling, J. M.; Cheng, Tsarng-Sheng

    1990-01-01

    Spontaneous vibrational Raman scattering (VRS) is produced by a broadband excimer laser at 248 nm (KrF) in a H2-air flame, and VRS spectra are recorded for lean, stoichiometric, and rich flames. Except at very lean flame conditions, laser-induced fluorescence (LIF) processes interfere with VRS Stokes lines from H2, H2O, and O2. No interference is found for the N2 Stokes and N2 anti-Stokes lines. In a stoichiometric H2/air flame, single-pulse measurements of N2 concentration and temperature (by the VRS Stokes to anti-Stokes ratio) have a relative standard deviation of 7.7 and 10 percent, respectively. These single pulse measurement errors compare well with photon statistics calculations using measured Raman cross sections.

  1. Some experiences with absorption, phonon Raman, and luminescence spectroscopic probes of crystal structure of f-element compounds

    International Nuclear Information System (INIS)

    Peterson, J.R.

    1992-01-01

    Structural information is crucial to the study and understanding of the basic chemical properties of the f elements. X-ray diffraction (XRD) techniques are usually used to obtain crystal structure information. However, the transuranium (5f) elements, because of their radioactivity and limited availability, present problems for standard XRD analysis. For some time now we have been developing and using various spectroscopic probes of crystal structure; an overview of our research in this area is presented here

  2. Application of spectroscopic methods (FT-IR, Raman, ECD and NMR) in studies of identification and optical purity of radezolid

    Science.gov (United States)

    Michalska, Katarzyna; Gruba, Ewa; Mizera, Mikołaj; Lewandowska, Kornelia; Bednarek, Elżbieta; Bocian, Wojciech; Cielecka-Piontek, Judyta

    2017-08-01

    In the presented study, N-{[(5S)-3-(2-fluoro-4‧-{[(1H-1,2,3-triazol-5-ylmethyl)amino]methyl}biphenyl-4-yl)-2-oxo-1,3-oxazolidin-5-yl]methyl}acetamide (radezolid) was synthesized and characterized using FT-IR, Raman, ECD and NMR. The aim of this work was to assess the possibility of applying classical spectral methods such as FT-IR, Raman, ECD and NMR spectroscopy for studies on the identification and optical purity of radezolid. The experimental interpretation of FT-IR and Raman spectra of radezolid was conducted in combination with theoretical studies. Density functional theory (DFT) with the B3LYP hybrid functional was used for obtaining radezolid spectra. Full identification was carried out by COSY, 1H {13C} HSQC and 1H {13C} HMBC experiments. The experimental NMR chemical shifts and spin-spin coupling constants were compared with theoretical calculations using the DFT method and B3LYP functional employing the 6-311 ++G(d,p) basis set and the solvent polarizable continuum model (PCM). The experimental ECD spectra of synthesized radezolid were compared with experimental spectra of the reference standard of radezolid. Theoretical calculations enabled us to conduct HOMO and LUMO analysis and molecular electrostatic potential maps were used to determine the active sites of microbiologically active form of radezolid enantiomer. The relationship between results of ab initio calculations and knowledge about chemical-biological properties of S-radezolid and other oxazolidinone derivatives are also discussed.

  3. Raman and IR spectroscopic structural characterization of LiAlO2 powders prepared using a liquid mix technique

    International Nuclear Information System (INIS)

    Cornilsen, B.C.; Loyselle, P.L.; Saporta, J.D.

    1990-01-01

    γ-LiAlO 2 and β-LiAlO 2 have been characterized using Raman and infrared spectroscopy. Powders have been prepared using two different preparation techniques: a solution method known as the liquid mix technique (LMT) and the traditional ceramic method. The authors find that the LMT allows direct production of single phase γ-LiAlO 2 at 600 degrees C, below that found using other preparation methods. Furthermore, this solution technique appears to avoid formation of the β-LiAlO 2 intermediate phase. At lower temperatures, the LMT product is a disordered precursor of γ- LiAlO 2

  4. The spectroscopic (FTIR, FT-Raman and UV-Vis spectra), DFT and normal coordinate computations of m-nitromethylbenzoate.

    Science.gov (United States)

    Gnanasambandan, T; Gunasekaran, S; Seshadri, S

    2013-08-01

    A combined experimental and theoretical study on molecular structure, vibrational spectra, NBO and UV-spectral analysis of m-nitromethylbenzoate (MNMB) has been reported in the present work. The FT-IR solid phase (4000-400 cm(-1)) and FT-Raman spectra (3500-100 cm(-1)) of MNMB was recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of MNMB in the ground-state have been calculated by using the density functional method B3LYP with 6-31G (d,p) and 6-31+G(d,p) basis sets. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). Stability of the molecule arising from hyperconjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the σ* antibonding orbitals and E(2) energies confirms the occurrence of ICT (Intra-molecular Charge Transfer) within the molecule. The UV spectrum was measured in ethyl acetate solution. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally the calculation results were applied to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Spectroscopic properties of neuroleptics: IR and Raman spectra of Risperidone (Risperdal) and of its mono- and di-protonated forms

    Science.gov (United States)

    Alparone, Andrea

    2011-10-01

    Structures and IR and Raman spectra of Risperidone in its neutral, mono- and di-protonated forms were calculated in gas phase by DFT-B3LYP/6-31G* level. Mono-protonation occurs at the nitrogen atom of the piperidine ring, while nitrogen atom of the pyrimidine ring is the preferred site for the second protonation. The lowest-energy structure of the mono-protonated Risperidone is characterized by formation of a strong seven-membered O(pyrimidine ring)⋯ +H-N(piperidine ring) intramolecular hydrogen-bonded cycle. In the high-energy spectral region (3500-2500 cm -1), the bands of the N-H + stretches and the changes in wavenumbers and IR intensities of the C-H stretches near to the piperidine nitrogen atom (Bohlmann effect) are potentially useful to discriminate conformations and protonation states. Di-protonated structures can be identified by the presence of an isolated absorption peak located in the low-energy IR region (660-690 cm -1), attributed to the out-of-plane N-H +(pyrimidine ring) bending deformation. The most intense Raman band of neutral Risperidone placed at ca. 1500 cm -1, assigned to C dbnd C(pyrimidine ring) stretch + C dbnd N(pyrimidine ring) stretch, can be a useful vibrational marker to distinguish the neutral from the protonated forms.

  6. Energy profile, spectroscopic (FT-IR, FT-Raman and FT-NMR) and DFT studies of 4-bromoisophthalic acid

    Science.gov (United States)

    Arjunan, V.; Thirunarayanan, S.; Mohan, S.

    2018-04-01

    The stable conformer of 4-bromoisophthalic acid (BIPA) has been identified by potential energy profile analysis. All the structural parameters of 4-bromoisophthalic acid are determined by B3LYP method with 6-311++G**, 6-31G** and cc-pVTZ basis sets. The fundamental vibrations are analysed with the use of FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm-1) spectra. The harmonic vibrational frequencies are theoretically calculated and compared with experimental FTIR and FT-Raman frequencies. The 1H and 13C NMR spectra have been analysed and compared with theoretical 1H and 13C NMR chemical shifts calculated by gauge independent atomic orbital (GIAO) method. The electronic properties, such as HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies are determined by B3LYP/cc-pVTZ method. The electron density distribution and site of chemical reactivity of BIPA molecule have been obtained by mapping electron density isosurface with molecular electrostatic potential (MEP). Stability of the molecules arising from hyperconjugative interactions, charge delocalizations have been analysed by using natural bond orbital (NBO) analysis. The thermodynamic properties and atomic natural charges of the compound are analysed and the reactive sites of the molecule are identified. The global and local reactivity descriptors are evaluated to analyse the chemical reactivity and site selectivity of molecule through Fukui functions.

  7. Comparison of stratum corneum thickness between two proposed methods of calculation using Raman spectroscopic depth profiling of skin water content.

    Science.gov (United States)

    Lee, M; Won, K; Kim, E J; Hwang, J S; Lee, H K

    2018-02-20

    The stratum corneum (SC) is the most important layer for the barrier function of skin, so investigation of the SC is very important in cosmetic and medical research. Here, we calculated the SC thickness using the depth profile of the skin's water concentration based on previously described methods, and then compared the results. Seven Korean women in their 30s participated in this study. Raman spectroscopy was used to measure the in vivo depth profile of skin water concentration. A total of 21 areas were measured at forearm. Microsoft Excel 2007 was used to calculate SC thickness based on the slope and intersection methods. The slope method and the intersection method gave a forearm SC thickness calculated at 21.3 ± 2.6 μm and 17.6 ± 2.8 μm, respectively. There was a significant difference between the two calculation methods but the two methods showed strong correlation of SC thickness results (r = .899). Although there was a difference in calculated SC thickness of about 20% between the two methods, these results reveal that the two SC thickness calculation methods using Raman spectroscopy were suitable for measuring SC thickness, a finding consistent with other published results. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Spectroscopic [FT-IR and FT-Raman] and molecular modeling (MM) study of benzene sulfonamide molecule using quantum chemical calculations

    Science.gov (United States)

    Vinod, K. S.; Periandy, S.; Govindarajan, M.

    2016-07-01

    The spectroscopic and molecular modeling (MM) study includes, FT-IR, FT-Raman and 13C NMR and 1H NMR spectra of the Benzene sulfonamide were recorded for the analysis. The observed experimental and theoretical frequencies (IR and Raman) were assigned according to their distinctive region. The present study of this title molecule have been carried out by hybrid computational calculations of HF and DFT (B3LYP) methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are tabulated. The structural modifications of the compound due to the substitutions of NH2 and SO2 were investigated. The minimum energy conformers of the compound were studied using conformational analysis. The alternations of the vibrational pattern of the base structure related to the substitutions were analyzed. The thermodynamic parameters (such as zero-point vibrational energy, thermal energy, specific heat capacity, rotational constants, entropy, and dipole moment) of Benzene sulfonamide have been calculated. The donor acceptor interactions of the compound and the corresponding UV transitions are found out using NBO analysis. The NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts related to TMS were compared. A quantum computational study on the electronic and optical properties absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by HF and DFT methods. The energy gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand group. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures were calculated in gas phase and

  9. A Nd:YAG Laser-Pumped Hydrogen Raman Shifter with Capillary Waveguide

    Directory of Open Access Journals (Sweden)

    Maria Leilani Torres

    2005-06-01

    Full Text Available Operation of a 355/532 nm Nd:YAG laser-pumped hydrogen Raman shifter with capillary waveguide (CWG is demonstrated. For both pump wavelengths, more laser lines are generated using the Raman shifter with CWG compared to a conventional Raman shifter. Both 355 and 532 nm pumps showed a 60% decrease in threshold power for the generated first Stokes (S1 Laser line. The 355 nm-pumped Raman shifter with CWG generated S1 at 2.1 mW pump power at a hydrogen pressure of 1.38 MPa. On the other hand, for the 532 nm pumped waveguide Raman shifter at a hydrogen pressure of 1.72 MPa, the threshold power for S1 is at 8.3 mW. In addition, an improvement of the output powers is observed for the Stokes and anti-Stokes generated by Raman shifter with CWG.

  10. Spectroscopic (UV/VIS, Raman) and Electrophoresis Study of Cytosine-Guanine Oligonucleotide DNA Influenced by Magnetic Field.

    Science.gov (United States)

    Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Boon Tong, Goh; Abdul Rahman, Saadah

    2016-01-01

    Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100), is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT). As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.

  11. Spectroscopic (UV/VIS, Raman and Electrophoresis Study of Cytosine-Guanine Oligonucleotide DNA Influenced by Magnetic Field.

    Directory of Open Access Journals (Sweden)

    Seyedeh Maryam Banihashemian

    Full Text Available Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100, is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT. As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.

  12. Raman spectroscopic studies on matrix-isolated arsenic and antimony molecules As 4 and Sb 4 in noble gas matrices

    Science.gov (United States)

    Kornath, Andreas J.; Kaufmann, Alexander; Cappellacci, Sebastian

    2009-06-01

    The Raman spectra of As 4 and Sb 4 molecules have been studied in neon, argon, krypton, and xenon matrices at 7 K. The vibrational frequencies of the As 4 molecule are up to 17 cm -1 higher than the experimental gas phase data. This evident blue-shift is not caused by matrix effects but originates from an underestimation of the fundamentals in the gas phase as a course of the elevated temperatures. The observed frequencies of As 4 and Sb 4 show a linear dependence toward the matrix host polarizability. Extrapolated values for zero polarizability which best represent a free molecule, are considered fundamental frequencies. The general valence force fields of As 4 and Sb 4 were calculated from the extrapolated frequencies.

  13. Raman spectroscopic analysis of human skin tissue sections ex-vivo: evaluation of the effects of tissue processing and dewaxing

    Science.gov (United States)

    Ali, Syed M.; Bonnier, Franck; Tfayli, Ali; Lambkin, Helen; Flynn, Kathleen; McDonagh, Vincent; Healy, Claragh; Clive Lee, T.; Lyng, Fiona M.; Byrne, Hugh J.

    2013-06-01

    Raman spectroscopy coupled with K-means clustering analysis (KMCA) is employed to elucidate the biochemical structure of human skin tissue sections and the effects of tissue processing. Both hand and thigh sections of human cadavers were analyzed in their unprocessed and formalin-fixed, paraffin-processed (FFPP), and subsequently dewaxed forms. In unprocessed sections, KMCA reveals clear differentiation of the stratum corneum (SC), intermediate underlying epithelium, and dermal layers for sections from both anatomical sites. The SC is seen to be relatively rich in lipidic content; the spectrum of the subjacent layers is strongly influenced by the presence of melanin, while that of the dermis is dominated by the characteristics of collagen. For a given anatomical site, little difference in layer structure and biochemistry is observed between samples from different cadavers. However, the hand and thigh sections are consistently differentiated for all cadavers, largely based on lipidic profiles. In dewaxed FFPP samples, while the SC, intermediate, and dermal layers are clearly differentiated by KMCA of Raman maps of tissue sections, the lipidic contributions to the spectra are significantly reduced, with the result that respective skin layers from different anatomical sites become indistinguishable. While efficient at removing the fixing wax, the tissue processing also efficiently removes the structurally similar lipidic components of the skin layers. In studies of dermatological processes in which lipids play an important role, such as wound healing, dewaxed samples are therefore not appropriate. Removal of the lipids does however accentuate the spectral features of the cellular and protein components, which may be more appropriate for retrospective analysis of disease progression and biochemical analysis using tissue banks.

  14. Enhanced Control of Transient Raman Scattering Using Buffered Hydrogen in Hollow-Core Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-12-01

    Many reports on stimulated Raman scattering in mixtures of Raman-active and noble gases indicate that the addition of a dispersive buffer gas increases the phase mismatch to higher-order Stokes and anti-Stokes sidebands, resulting in a preferential conversion to the first few Stokes lines, accompanied by a significant reduction in the Raman gain due to collisions with gas molecules. Here we report that, provided the dispersion can be precisely controlled, the effective Raman gain in a gas-filled hollow-core photonic crystal fiber can actually be significantly enhanced when a buffer gas is added. This counterintuitive behavior occurs when the nonlinear coupling between the interacting fields is strong and can result in a performance similar to that of a pure Raman-active gas, but at a much lower total gas pressure, allowing competing effects such as Raman backscattering to be suppressed. We report high modal purity in all the emitted sidebands, along with anti-Stokes conversion efficiencies as high as 5% in the visible and 2% in the ultraviolet. This new class of gas-based waveguide device, which allows the nonlinear optical response to be beneficially pressure-tuned by the addition of buffer gases, may find important applications in laser science and spectroscopy.

  15. High-resolution inverse Raman and resonant-wave-mixing spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

  16. Raman spectroscopic analysis of the increase of the carotenoid antioxidant concentration in human skin after a 1-week diet with ecological eggs

    Science.gov (United States)

    Hesterberg, Karoline; Lademann, Jürgen; Patzelt, Alexa; Sterry, Wolfram; Darvin, Maxim E.

    2009-03-01

    Skin aging is mainly caused by the destructive action of free radicals, produced by the UV light of the sun. The human skin has developed a protection system against these highly reactive molecules in the form of the antioxidative potential. Carotenoids are one of the main components of the antioxidants of the human skin. From former studies, it is known that skin aging is reduced in individuals with high levels of carotenoids. Because most of the antioxidants cannot be produced by the human organism, they must be up taken by nutrition. Using noninvasive Raman spectroscopic measurements it is demonstrated that not only fruits and vegetables but also eggs contain high concentrations of antioxidants including carotenoids, which are even doubled in the case of ecological eggs. After a 1-week diet with ecological eggs performed by six volunteers, it is found that the concentration of the carotenoids in the skin of the volunteers increased by approx. 20%. Our study does not intend to recommend exorbitant egg consumption, as eggs also contain harmful cholesterol. But in the case of egg consumption, ecological eggs from hens kept on pasture should be preferred to also receive a benefit for the skin.

  17. FT-IR and FT-Raman, NMR and UV spectroscopic investigation and hybrid computational (HF and DFT) analysis on the molecular structure of mesitylene.

    Science.gov (United States)

    Kose, E; Atac, A; Karabacak, M; Nagabalasubramanian, P B; Asiri, A M; Periandy, S

    2013-12-01

    The spectroscopic properties of mesitylene were investigated by FT-IR, FT-Raman, UV, (1)H and (13)C NMR techniques. The geometrical parameters and energies have been obtained from density functional theory (DFT) B3LYP method and Hartree-Fock (HF) method with 6-311++G(d,p) and 6-311G(d,p) basis sets calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. (13)C and (1)H NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. Reduced density gradient (RDG) of the mesitylene was also given to investigate interactions of the molecule. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation on 1-phenyl-2-nitropropene by quantum computational calculations.

    Science.gov (United States)

    Xavier, S; Periandy, S

    2015-01-01

    In this paper, the spectral analysis of 1-phenyl-2-nitropropene is carried out using the FTIR, FT Raman, FT NMR and UV-Vis spectra of the compound with the help of quantum mechanical computations using ab-initio and density functional theories. The FT-IR (4000-400 cm(-1)) and FT-Raman (4000-100 cm(-1)) spectra were recorded in solid phase, the (1)H and (13)C NMR spectra were recorded in CDCl3 solution phase and the UV-Vis (200-800 nm) spectrum was recorded in ethanol solution phase. The different conformers of the compound and their minimum energies are studied using B3LYP functional with 6-311+G(d,p) basis set and two stable conformers with lowest energy were identified and the same was used for further computations. The computed wavenumbers from different methods are scaled so as to agree with the experimental values and the scaling factors are reported. All the modes of vibrations are assigned and the structure the molecule is analyzed in terms of parameters like bond length, bond angle and dihedral angle predicted by both B3LYP and B3PW91 methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets. The values of dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the molecule are reported, using which the non-linear property of the molecule is discussed. The HOMO-LUMO mappings are reported which reveals the different charge transfer possibilities within the molecule. The isotropic chemical shifts predicted for (1)H and (13)C atoms using gauge invariant atomic orbital (GIAO) theory show good agreement with experimental shifts. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. The local reactivity of the molecule has been studied using the Fukui function. The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Surface enhanced Raman spectroscopic studies on magnetic Fe3O4@AuAg alloy core-shell nanoparticles

    Science.gov (United States)

    Sun, Hai-Long; Xu, Min-Min; Guo, Qing-Hua; Yuan, Ya-Xian; Shen, Li-Ming; Gu, Ren-Ao; Yao, Jian-Lin

    2013-10-01

    A facile approach has been developed to fabricate multifunctional Fe3O4@AuAg alloy core-shell nanoparticles, owning the magnetism of the core and the surface enhanced Raman spectroscopy (SERS) activities of the alloy shell. By changing the amount of HAuCl4 and AgNO3, Fe3O4@AuAg alloy nanoparticles with different component ratios of Au and Ag were successfully prepared. The surface plasmon resonance of the composition was linearly tuned in a wide range by varying the molar fraction of Ag and Au, suggesting the formation of AuAg alloy shell. SERS and magnetic enrichment effects were investigated by using thiophenol (TP) as the probe molecule. The SERS intensity was strongly dependent on the molar ratios of Au and Ag and the excitation line. Enrichment for the molecules with low concentration and on line SERS monitoring experiments were performed through combining the magnetism of the core and the SERS effect of the alloy shell. The results revealed that the magnetic enrichment efficiency was dramatically increased due to the strong magnetism of Fe3O4 core. In addition, the Fe3O4@AuAg nanoparticles were also used in the microfluidic chip to continuously detect different flowing solution in the channel. The detection time and amount of analyte were successfully decreased.

  20. Micro-Raman spectroscopic identification of natural mineral phases and their weathering products inside an abandoned zinc/lead mine.

    Science.gov (United States)

    Goienaga, N; Arrieta, N; Carrero, J A; Olivares, M; Sarmiento, A; Martinez-Arkarazo, I; Fernández, L A; Madariaga, J M

    2011-10-01

    Mining activities provide a good source of minerals of different nature. On the one hand, the primary minerals for whose formation a geological time-scale is required. On the other hand, secondary minerals, formed from removed products after the earlier weathering and alteration states. These are characteristic of the local geology and the environment context that commonly appears due to the low chemical stability of their original primary minerals. This work shows how quickly the reactions promoting secondary minerals may have taken place, due to the fact that these were found in newly formed solid materials called efflorescences. To achieve this purpose, the sampling is crucial. It was carried out in such a way that tried to guarantee that the samples collected consisted in the very top soil matter (first 2 cm depth). Thus, unlike the deeper soil, the material analysed may have been newly formed due to the interactions that they had with the place weathering agents (i.e. air oxygen, humidity, and microbial activities). Raman spectroscopy has emerged as a good and fast non-destructive technique that provides molecular information of the local mineralogy without the need of any pre-treatment of the samples. At the same time, the work looked for information on the variety of non-stable lead and-or zinc containing minerals due to the possible health and environmental risks they convey. Among the different minerals identified, 16 were of primary nature while 23 may be classified as secondary minerals, probably formed in the last decades as the result of the extractive activities. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Insilico molecular modeling, docking and spectroscopic [FT-IR/FT-Raman/UV/NMR] analysis of Chlorfenson using computational calculations.

    Science.gov (United States)

    Ramalingam, S; Periandy, S; Sugunakala, S; Prabhu, T; Bououdina, M

    2013-11-01

    In the present work, the recorded FT-IR/FT-Raman spectra of the Chlorfenson (4-Chorophenyl-4-chlorobenzenesulfonate) are analysed. The observed vibrational frequencies are assigned and the computational calculations are carried out by DFT (LSDA, B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are investigated with the UV/NMR data. The fluctuation of structure of Chlorobenzenesulfonate due to the substitution of C6H4Cl is investigated. The vibrational sequence pattern of the molecule related to the substitutions is intensely analysed. Moreover, (13)C NMR and (1)H NMR chemical shifts are calculated by using the gage independent atomic orbital (GIAO) technique with HF/B3LYP/B3PW91 methods on same basis set. A study on the electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The calculated energy of Kubo gap (HOMO and LUMO) ensures that the charge transfer occurs within the molecule. Besides frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) is executed. NLO properties and Mulliken charges of the Chlorfenson is also calculated and interpreted. Biological properties like the target receptor identification, and Identification of interacting residues, of this compound is identified and analysed by using SWISSMODEL, Castp, Hex and Pdb Sum. By using these properties, the mechanism of action of this compound on ATP Synthase of Tetranychus urticae is found and it is very much useful to develop efficient pesticides having less toxic to the environment. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  2. FT-Raman spectroscopic study of skin wound healing in diabetic rats treated with Cenostigma macrophyllum Tul

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Nayana Pinheiro Machado de Freitas; Martins, Marcelino, E-mail: nayanamachado@oi.com.br [Faculdade Diferencial Integral (FACID), Teresina, PI (Brazil); Costa, Charlytton Luis Sena da; Maia Filho, Antonio Luis [Universidade Estadual do Piaui (UESPI), Teresina, PI (Brazil); Raniero, Leandro; Martin, Airton Abrahao; Arisawa, Emilia Angela Loschiavo [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil). Instituto de Pesquisa e Desenvolvimento

    2014-07-01

    Introduction: patients with diabetes mellitus exhibit a delay in the lesion repair process. The active components of Cenostigma macrophyllum may represent a viable alternative to facilitate the recovery of these lesions. The aim of this study was to evaluate the effects of emulsion oil-water Cenostigma macrophyllum in the repair process of lesions in rats with induced diabetes. Methods: 63 male rats (Wistar, 200-250 g body weight, 30-40 days old) were distributed into the following groups: control (C), diabetic (D) and diabetic treated with Cenostigma macrophyllum (P), subdivided based on the experimental times, days 7, 14 and 28, with 21 animals per main group. Diabetes mellitus (DM) was induced by administration of streptozotocin (50 mg/kg via penile vein and 12-h fasting) and confirmed at day 21 (glycemic index > 240 mg/dL). In the animals of group P, 0.5 ml of the oil-water emulsion obtained from the plant seed was used. The samples were removed and hemisectioned, and one portion was used for the quantitative histological analysis of collagen using Masson's trichrome staining, while another portion was analyzed by FT-Raman spectroscopy. Results: A higher percentage area of the volume of collagen fibers was observed for the experimental time Day 14 in group P compared with group D (p < 0.001). Regarding the ratio of areas of the amides I (1700-1600 cm{sup -1}) and III (1245-1345 cm{sup -1}), the groups D and P show the opposite behavior. Conclusion: Cenostigma macrophyllum accelerated the repair process in skin of diabetic ratsfor14 days. (author)

  3. Spectroscopic (far or terahertz, mid-infrared and Raman) investigation, thermal analysis and biological activity of piplartine

    Science.gov (United States)

    Srivastava, Anubha; Karthick, T.; Joshi, B. D.; Mishra, Rashmi; Tandon, Poonam; Ayala, A. P.; Ellena, Javier

    2017-09-01

    Research in the field of medicinal plants including Piper species like long pepper (Piper longum L.- Piperaceae) is increasing all over the world due to its use in traditional and Ayurvedic medicine. Piplartine (piperlongumine, 5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone), a biologically active alkaloid/amide was isolated from the phytochemical investigations of Piper species, as long pepper. This alkaloid has cytotoxic, anti-fungal, anti-diabetic, anti-platelet aggregation, anti-tumoral, anxiolytic, anti-depressant, anti-leishmanial, and genotoxic activities, but, its anticancer property is the most promising and has been widely explored. The main purpose of the work is to present a solid state characterization of PPTN using thermal analysis and vibrational spectroscopy. Quantum mechanical calculations based on the density functional theory was also applied to investigate the molecular conformation and vibrational spectrum, which was compared with experimental results obtained by Raman scattering, far (terahertz) and mid-infrared adsorption spectroscopy. NBO analysis has been performed which predict that most intensive interactions in PPTN are the hyperconjugative interactions between n(1) N6 and π*(O1sbnd C7) having delocalization energy of 50.53 kcal/mol, Topological parameters have been analyzed using 'AIM' analysis which governs the three bond critical points (BCPs), one di-hydrogen, and four ring critical points (RCPs). MEP surface has been plotted which forecast that the most negative region is associated with the electronegative oxygen atoms (sites for nucleophilic activity). Theoretically, to confirm that the title compound has anti-cancer, anti-diabetic and anti-platelet aggregation activities, it was analyzed by molecular docking interactions with the corresponding target receptors. The obtained values of H-bonding parameters and binding affinity prove that its anti-cancer activity is the more prominent than the

  4. Protein structural changes in keratin fibers induced by chemical modification using 2-iminothiolane hydrochloride: a Raman spectroscopic investigation.

    Science.gov (United States)

    Kuzuhara, Akio

    2005-11-01

    For the purpose of investigating in detail the influence of chemical modification using 2-iminothiolane hydrochloride (2-IT) on keratin fibers, the structure of cross-sections at various depths of white human hair, treated with 2-IT and then oxidized, was directly analyzed without isolating the cuticle and cortex, using Raman spectroscopy. In particular, the beta-sheet and/or random coil content (beta/R) and the alpha-helix (alpha) content in human hair fibers were estimated by amide I band analysis. The S-S band intensity, amide III (unordered) band intensity, and beta/R content existing from the cuticle region to the center of cortex region of virgin white human hair remarkably increased by performing the chemical modification using 2-IT. On the other hand, not only the S-S band intensity, but also S-O band intensity existing throughout the cortex region of the bleached (damaged) white human hair increased by performing chemical modification using 2-IT. In particular, beta/R content existing throughout the cortex region of the bleached white human hair decreased, while the skeletal C-C stretch (alpha) band intensity at 935 cm(-1) and the alpha content remarkably increased. This indicates a secondary structural change from the random coil form to the alpha-helix form in the proteins existing throughout the cortex region. From these experiments, we concluded that the formation of new disulfide (-SS-) groups resulting from chemical modification using 2-IT induced the secondary structural changes of proteins existing throughout the cortex region. Copyright 2005 Wiley Periodicals, Inc

  5. A Raman spectroscopic investigation of the mechanism of the reduction in hair with thioglycerol and the accompanying disulphide conformational changes.

    Science.gov (United States)

    Kuzuhara, A

    2018-02-01

    The objective of our research was to investigate the reduction mechanism of thioglycerol (TG) on hair keratin fibres. The structure of cross-sections at various depths of virgin white human hair resulting from the permanent waving process with TG was directly analysed at the molecular level using Raman spectroscopy. Also, the penetration of TG for the cross-sectional samples dyed with methylene blue was observed by optical microscopy. The gauche-gauche-gauche (GGG) and gauche-gauche-trans (GGT) conformations of disulphide (-SS-) groups remarkably decreased, while the trans-gauche-trans (TGT) conformation increased by performing the reduction process with TG. In addition, the disconnected -SS- content at various depths of the hair sample reduced with TG adjusted to pH 9.0 with ammonia solution was clearly increased compared with that of the hair sample reduced with TG adjusted to pH 9.0 with monoethanolamine. In the case of adjusting to pH 9.0 with ammonia solution, the tensile strength of the waved hair treated with TG was strong compared with that of the waved hair treated with thioglycolic acid (TGA), but the waving efficiency of the waved hair treated with TG was nevertheless higher than that of the waved hair treated with TGA. The author concluded that the waved virgin human hair treated with TG adjusted to pH 9.0 with ammonia solution was less damaged as compared with the waved hair treated with TGA, despite its good waving efficiency, as not only were the GGG and GGT conformations disconnected, but they were also changed to the TGT conformation by performing the reduction process with TG. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  6. Internal structural changes in keratin fibres resulting from combined hair waving and stress relaxation treatments: a Raman spectroscopic investigation.

    Science.gov (United States)

    Kuzuhara, A

    2016-04-01

    The objective of our research was to investigate the influence of chemical treatments (reduction, stress relaxation and oxidation) on hair keratin fibres. The structure of cross-sections at various depths of virgin white human hair resulting from permanent waving treatments with stress relaxation process was directly analysed at a molecular level using Raman spectroscopy. In particular, the three disulphide (-SS-) conformations in human hair were compared by S-S band analysis. The gauche-gauche-gauche (GGG) and gauche-gauche-trans (GGT) contents of -SS- groups remarkably decreased, while the trans-gauche-trans (TGT) content was not changed by performing the reduction process with thioglycolic acid. In addition, the high-temperature stress relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups in the human hair, while the low-temperature stress relaxation process after reduction accelerated the reconnection of -SS- (GGG and GGT) groups. Moreover, the S-O band intensity at 1042 cm(-1) , assigned to cysteic acid, existing in the cuticle region and the surface of the cortex region increased, while the GGG content significantly decreased by performing the oxidation process after the reduction and the high-temperature stress relaxation processes. The author concluded that the high-temperature relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups, thereby leading to the remarkable local molecular disorganization (an increase in the cysteic acid content and a decrease in the GGG content) on the cuticle and cortex cells during the oxidation process. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  7. Raman Spectroscopic Online Investigation of Respiratory Quotients in Pinus Sylvestris and Picea Abies during Drought and Shading

    Science.gov (United States)

    Hanf, S.; Fischer, S.; Hartmann, H.; Trumbore, S.; Popp, J.; Frosch, T.

    2014-12-01

    Drought and heat waves have been linked to forest mortality event across the globe. The underlying physiological processes are still not elucidated but both tree carbon and water relations have been identified as the driving forces. While studies on tree hydraulics are straightforward, studies on the tree carbon balance are not. For example, the use of different carbon compounds for maintenance respiration during drought cannot be assessed with measurements of carbon pools but requires real-time analyses of respiration stoichiometry. However, so far there were no technical solutions for such applications. Here we introduce cavity-enhanced Raman spectrometry (CERS) for simultaneous real-time monitoring of O2 and CO2 and rapid and continuous quantification of dark respiration rates and the respiratory quotient (RQ), i.e. the ratio of CO2 produced over O2 consumed during respiration. This ratio indicates the proportions of different substrates (carbohydrates [COH], lipids, proteins) used during respiration and allows fundamental insights into tree physiology. CERS combines high temporal resolution with a high dynamic concentration range for all important gases, ranging from few ppm to 100 vol. % with a single measurement every few seconds. The respiration analysis of tree branches was performed in a closed chamber for two species of different drought tolerance, Pinus sylvestris and Picea abies. We applied not only drought but also a shading treatment because both cause reductions in carbon assimilation rates but have different effects on tree hydraulics. Declines in RQ during shading in both species indicate a switch from pure COH metabolism to a mixture of COH, lipids and proteins. During drought such declines occurred only in the drought-tolerant pine but not in spruce and the underlying more dynamic carbon use strategy in pine may provide a physiological basis for its drought tolerance, more detailed investigation still pending. Our study highlights the suitability

  8. Formation of hydrothermal tin deposits: Raman spectroscopic evidence for an important role of aqueous Sn(IV) species

    Science.gov (United States)

    Schmidt, Christian

    2018-01-01

    The speciation of tin and the solubility of cassiterite in H2O + HCl were determined at temperatures to 600 °C using in situ Raman spectroscopy. In addition, information on the fluid-melt partition of Sn was obtained at 700 °C and indicated a preference of the fluid only at HCl concentrations that are much higher than in fluids exsolved from natural felsic melts. Dissolution of cassiterite generally resulted in formation of Sn(IV) species unless reduced conditions were generated by hydrogen permeation or carbohydrates in the starting material. The prevalent aqueous Sn(IV) species was [SnCl4(H2O)2]0, with additional [SnCl3(H2O)3]+ and [SnCl5(H2O)]-. The only detectable Sn(II) species was very likely [Sn(II)Cl3]-. Cassiterite solubility increased with HCl concentration and was generally high in H2O+HCl fluids, with no strong dependencies on temperature, pressure, or the oxidation state of tin in the fluid. The Sn(IV) concentrations at 500 and 600 °C determined from the integrated ν1[Sn(IV)sbnd Cl] band intensity are in good agreement with literature data on the cassiterite solubility in H2O + HCl at oxygen fugacities along the hematite-magnetite buffer. The combined results from previous experimental studies and this study demonstrate that HCl molality is a crucial parameter for hydrothermal mobilization and transport of tin and for cassiterite precipitation, and that pH, pressure and temperature are less important. Current models on hydrothermal tin deposit formation need to be augmented to include Sn(IV)sbnd Cl complexes as significant tin-transporting species. Irrespective of the oxidation state of tin in the fluid, cassiterite precipitates due to reaction of the hydrothermal fluid with the wall rock (greisen or skarn formation), dilution (mixing with meteoric water) or a decrease in the HCl activity in the aqueous liquid by boiling. A redox reaction is only required for tin transported as Sn(II) to be converted to Sn(IV).

  9. In Situ Raman Spectroscopic Observations of Gas-Saturated Rising Oil droplets: Simulation with Decane as an Oil-Equivalent Substitute

    Science.gov (United States)

    Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

    2016-02-01

    Oil droplets rising from the sea floor, whether from seeps or well leakage, contain very large quantities of dissolved gas that profoundly affects their density and critical oil-water interfacial characteristics. The primary dissolved gas is methane which may be up to 30% of the molar volume. This can create a hydrate skin as the methane gas is shed from the oil as it rises through the water column, thus decreasing in pressure and increasing in temperature, and steadily changing the rising droplet buoyancy. We have explored this phenomenon by executing controlled ROV based experiments with a "bubble cup" technique in which a small volume of gas saturated decane (saturated with pure methane, a mix of methane and nitrogen , or a mix of methane and CO2) is interrogated by laser Raman spectroscopy. The use of decane as an oil "substitute" is required since natural oil samples are highly fluorescent due to the presence of polycyclic aromatic hydrocarbons. We have devised Matlab techniques for extracting the spectroscopic dissolved methane signal from the thicket of decane peaks that surround it. We have directly observed the rate at which gases are lost from the "oil" per unit area at depths in the water column that are both within and outside the hydrate forming phase boundary. We have compared the behavior of both a non-hydrate forming dissolved gas (nitrogen) with CO2 where the hydrate phase boundary is at significantly shallower depth. The results indicate complex interfacial behavior and physical chemistry. We did not observe direct gas bubble formation on the decane outer surface but did observe gas bubble formation within the oil droplets as they rose through the water column. Because there are significant energy barriers for homogeneous bubble formation within the decane phase, we took this as evidence of significant gas super-saturation within the oil droplet. The gas loss rates increased significantly in all cases when the hydrate phase boundary was crossed.

  10. Synthesis, spectroscopic (FT-IR, FT-Raman, UV and NMR) and computational studies on 3t-pentyl-2r,6c-diphenylpiperidin-4-one semicarbazone.

    Science.gov (United States)

    Arockia doss, M; Savithiri, S; Rajarajan, G; Thanikachalam, V; Saleem, H

    2015-09-05

    The structural and spectroscopic studies of 3t-pentyl-2r,6c-diphenylpiperidin-4-one semicarbazone (PDPOSC) were made by adopting B3LYP/HF levels theory using 6-311++G(d,p) basis set. The FT-IR and Raman spectra were recorded in solid phase, the fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. DFT method indicates that B3LYP is superior to HF method for molecular vibrational analysis. UV-vis spectrum of the compound was recorded in different solvents in the region of 200-800 nm and the electronic properties such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies were evaluated by time-dependent DFT (TD-DFT) approach. The polarizability and first order hyperpolarizability of the title molecule were calculated and interpreted. The hyperconjugative interaction energy (E((2))) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. In addition, MEP and atomic charges of carbon, nitrogen and oxygen were calculated using B3LYP/6-311++G(d,p) level theory. Moreover, thermodynamic properties of the title compound were calculated by B3LYP/HF, levels using 6-311++G(d,p) basis set. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid

    Science.gov (United States)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.

    2014-03-01

    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  12. Synthesis, spectroscopic characterization (FT-IR, FT-Raman, and NMR), quantum chemical studies and molecular docking of 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione

    Science.gov (United States)

    Avdović, Edina H.; Milenković, Dejan; Dimitrić Marković, Jasmina M.; Đorović, Jelena; Vuković, Nenad; Vukić, Milena D.; Jevtić, Verica V.; Trifunović, Srećko R.; Potočňák, Ivan; Marković, Zoran

    2018-04-01

    The experimental and theoretical investigations of structure of the 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione were performed. X-ray structure analysis and spectroscopic methods (FTIR and FT-Raman, 1H and 13C NMR), along with the density functional theory calculations (B3LYP functional with empirical dispersion corrections D3BJ in combination with the 6-311 + G(d,p) basis set), were used in order to characterize the molecular structure and spectroscopic behavior of the investigated coumarin derivative. Molecular docking analysis was carried out to identify the potency of inhibition of the title molecule against human's Ubiquinol-Cytochrome C Reductase Binding Protein (UQCRB) and Methylenetetrahydrofolate reductase (MTHFR). The inhibition activity was obtained for ten conformations of ligand inside the proteins.

  13. Molecular structure, vibrational spectroscopic analysis (IR & Raman), HOMO-LUMO and NBO analysis of anti-cancer drug sunitinib using DFT method

    Science.gov (United States)

    Mıhçıokur, Özlem; Özpozan, Talat

    2017-12-01

    Oxindole and its derivatives have wide applications in different industries such as in synthetic & natural fibers, dyes for hair and plastic materials in addition to their biological importance. In the present study, one of the oxindole derivatives, N-(2-diethylaminoethyl)-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide (Sunitinib), which is used as an anti-cancer drug, was investigated in terms of structural, vibrational spectroscopic and theoretical analysis. The calculations have been performed for gaseous, aqueous and DMSO phases, respectively. Potential Energy Surface (PES) scan has been carrried out to obtain the most stable structures of all the phases of the title molecule using B3LYP/6-31G(d,p) level and the geometrical variations among them are discussed. The solvent effect for Sunitinib in aqueous and DMSO phases have been performed by means of the self-consistent recognition reaction field (SCRF) method as implemented in the integral equation formalism polarized continuum model (IEFPCM). On the other hand, NBO analysis has been carried out to understand probable hydrogen bonding sites and charge transfers. Additionally, the HOMO and the LUMO energies are calculated using B3LYP/6-31G(d,p) to determine the intra molecular charge transfers (ICT) within the molecule and the kinetic stabilities for each phases. The molecular electrostatic potential surface (MESP) has been plotted over the optimized structure to estimate the reactive sites of electrophilic and nucleophilic attacks regarding Sunitinib molecule. The potential energy distribution (PED) has been calculated using VEDA4 program and vibrational assignments of the experimental spectra (IR & Raman) have been elucidated by means of the calculated vibrational spectra. The observed vibrational spectra of Sunitinib is compared with the calculated spectra obtained by using B3LYP functional both with 6-31G(d,p) and 6-311++G(d,p) basis sets. Theoretical results

  14. Inverse Raman scattering in silicon: A free-carrier enhanced effect

    International Nuclear Information System (INIS)

    Solli, D. R.; Koonath, P.; Jalali, B.

    2009-01-01

    Stimulated Raman scattering has been harnessed to produce the first silicon lasers and amplifiers. The Raman effect can also produce intensity-dependent nonlinear loss through a corollary process, inverse Raman scattering (IRS). This process has never been observed in a semiconductor. We demonstrate IRS in silicon--a process that is substantially modified by optically generated free carriers--achieving attenuation levels >15 dB with a pump intensity of 4 GW/cm 2 . Surprisingly, free-carrier absorption, the detrimental effect that generally suppresses nonlinear effects in silicon, actually facilitates IRS by delaying the onset of contamination from coherent anti-Stokes Raman scattering. Silicon-based IRS could be a valuable tool for chip-scale signal processing.

  15. Raman scattering of a photon with frequency doubling by a channelled positron

    Energy Technology Data Exchange (ETDEWEB)

    Kalashnikov, N P [National Research Nuclear University ' ' MEPhI' ' (Russian Federation); Krokhin, O N [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-12-31

    We have analysed the possibility of appearance of anti-Stokes lines in the spectrum of Raman scattering of a photon by a 'quasi-bound' charged particle in the regime of planar (axial) channelling. It is shown that radiation may emerge at the frequency, which is a combination of the incident photon frequency ω{sub 0} and transition frequency ω{sub i} in the transverse quantised motion of a channelled particle: ω = ω{sub 0} ± 2γ{sup 2}ω{sub i}, where γ is the relativistic (Lorentz) factor of a channelled particle. (nonlinear optical phenomena)

  16. Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators.

    Science.gov (United States)

    Farnesi, Daniele; Berneschi, Simone; Cosi, Franco; Righini, Giancarlo C; Soria, Silvia; Nunzi Conti, Gualtiero

    2016-04-04

    Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres can be thought as a store of energy with a huge variety of applications: compact laser sources, highly sensitive biochemical sensors and nonlinear phenomena. A protocol for the fabrication of both the microspheres and coupling system is given. The couplers described here are tapered fibers. Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility Χ((3)) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS). A proof of the cavity-enhanced phenomenon is given by the lack of correlation among the pump, signal and idler: a resonant mode has to exist in order to obtain the pair of signal and idler. In the case of hyperparametric oscillations (four wave mixing and stimulated anti-stokes Raman scattering), the modes must fulfill the energy and momentum conservation and, last but not least, have a good spatial overlap.

  17. Raman and infrared spectroscopic studies of the structure of water (H2O, HOD, D2O) in stoichiometric crystalline hydrates and in electrolyte solutions

    International Nuclear Information System (INIS)

    Buanam-Om, C.

    1981-01-01

    The chapter of reviews presents in particular the Badger-Bauer-rule, distance and angle dependence of O-H...Y hydrogen bond and the structure of aqueous electrolyte solutions. A chapter of vibrational spectroscopic investigations of crystalline hydrates - metal perchlorate hydrates follows. Two further chapters just so investigate metal halide hydrates and some sulfate hydrates and related systems. The following chapter describes near infrared spectroscopic investigations of HOD(D 2 O) and its electrolyte solutions. The concluding chapter contains thermodynamic consequences and some properties of electrolyte solutions from vibrational spectroscopic investigations. (SPI) [de

  18. Non-invasive in vivo determination of the carotenoids beta-carotene and lycopene concentrations in the human skin using the Raman spectroscopic method

    Energy Technology Data Exchange (ETDEWEB)

    Darvin, M E [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Gersonde, I [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Meinke, M [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Sterry, W [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Lademann, J [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany)

    2005-08-07

    Resonance Raman spectroscopy was used as a fast and non-invasive optical method of measuring the absolute concentrations of beta-carotene and lycopene in living human skin. Beta-carotene and lycopene have different absorption values at 488 and 514.5 nm and, consequently, the Raman lines for beta-carotene and lycopene have different scattering efficiencies at 488 and 514.5 nm excitations. These differences were used for the determination of the concentrations of beta-carotene and lycopene. Using multiline Ar{sup +} laser excitation, clearly distinguishable carotenoid Raman spectra can be obtained which are superimposed on a large fluorescence background. The Raman signals are characterized by two prominent Stokes lines at 1160 and 1525 cm{sup -1}, which have nearly identical relative intensities. Both substances were detected simultaneously. The Raman spectra are obtained rapidly, i.e. within about 10 s, and the required laser light exposure level is well within safety standards. The disturbance of the measurements by non-homogeneous skin pigmentation was avoided by using a relatively large measuring area of 35 mm{sup 2}. It was shown that beta-carotene and lycopene distribution in human skin strongly depends upon the skin region studied and drastically changed inter-individually. Skin beta-carotene and lycopene concentrations are lower in smokers than in non-smokers and higher in the vegetarian group.

  19. Vibrational spectroscopic (FTIR and FT-Raman), first-order hyperpolarizablity, HOMO, LUMO, NBO, Mulliken charge analyses of 2-ethylimidazole based on Hartree-Fock and DFT calculations.

    Science.gov (United States)

    Arivazhagan, M; Manivel, S; Jeyavijayan, S; Meenakshi, R

    2015-01-05

    The FTIR and FT-Raman spectra of 2-ethylimidazole (2EIDZ) have been recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. The optimized molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities, were calculated by ab initio Hartree-Fock (HF) and density functional theory (DFT/B3LYP) methods with 6-311++G(d,p) basis set. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of 2EIDZ is also reported based on total energy distribution (TED). The values of the total dipole moment (μ) and the first-order hyperpolarizability (β) of the compound were computed. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. Besides, HOMO and LUMO analysis, Mulliken's charge analysis and several thermodynamic properties have been calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Voltammetric and surface-enhanced resonance Raman spectroscopic characterization of cytochrome C adsorbed on a 4-mercaptopyridine monolayer on silver electrodes

    NARCIS (Netherlands)

    Millo, D.; Bonifacio, A.; Ranieri, A.; Borsari, M.; Gooijer, C.; van der Zwan, G.

    2007-01-01

    To combine voltammetric techniques with surface-enhanced resonance Raman scattering (SERRS), cytochrome c (cyt c) was immobilized on a roughened silver electrode chemically modified with a self-assembled monolayer (SAM) of 4-mercaptopyridine (PySH). All measurements were performed on the same

  1. A Raman scattering and FT-IR spectroscopic study on the effect of the solar radiation in Antarctica on bovine cornea

    Science.gov (United States)

    Yamamoto, Tatsuyuki; Murakami, Naoki; Yoshikiyo, Keisuke; Takahashi, Tetsuya; Yamamoto, Naoyuki

    2010-01-01

    The Raman scattering and FT-IR spectra of the corneas, transported to the Syowa station in Antarctica and exposed to the solar radiation of the mid-summer for four weeks, were studied to reveal that type IV collagen involved in corneas were fragmented. The amide I and III Raman bands were observed at 1660 and 1245 cm -1, respectively, and the amide I and II infrared bands were observed at 1655 and 1545 cm -1, respectively, for original corneas before exposure. The background of Raman signals prominently increased and the ratio of amide II infrared band versus amide I decreased by the solar radiation in Antarctica. The control experiment using an artificial UV lamp was also performed in laboratory. The decline rate of the amide II/amide I was utilized for estimating the degree of fragmentation of collagen, to reveal that the addition of vitamin C suppressed the reaction while the addition of sugars promoted it. The effect of the solar radiation in Antarctica on the corneas was estimated as the same as the artificial UV lamp of four weeks (Raman) or one week (FT-IR) exposure.

  2. Infrared and Raman spectroscopic characterization of the silicate mineral olmiite CaMn2+[SiO3(OH)](OH) - implications for the molecular structure

    Science.gov (United States)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Granja, Amanda; Žigovečki Gobac, Željka; Lima, Rosa Malena Fernandes

    2013-12-01

    We have studied the mineral olmiite CaMn[SiO3(OH)](OH) which forms a series with its calcium analogue poldervaartite CaCa[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is pure and contains only calcium and manganese in the formula. Thermogravimetric analysis proves the mineral decomposes at 502 °C with a mass loss of 8.8% compared with the theoretical mass loss of 8.737%. A strong Raman band at 853 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations. Two intense Raman bands observed at 3511 and 3550 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of olmiite.

  3. Spectroscopic (FT-IR, FT-Raman, UV-Vis) analysis, conformational, HOMO-LUMO, NBO and NLO calculations on monomeric and dimeric structures of 4-pyridazinecarboxylic acid by HF and DFT methods

    Science.gov (United States)

    Eşme, A.; Sağdınç, S. G.

    2017-11-01

    In this study, the Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 4-pyridazinecarboxylic acid (4PCA) in solid phase were recorded and analyzed. Quantum chemical calculations of the optimized molecular structure, energies, conformational, UV-Vis, nonlinear optical (NLO) and natural bond orbital (NBO) analysis, molecular surfaces, Mulliken charges, and vibrational studies for 4PCA were performed using the ab initio Hartree-Fock (HF) and density functional theory (DFT/B3LYP) methods with 6-311++G(d,p) basis set. Obtained results on the geometric structure and vibrational frequencies are compared with observed data. The dimeric structure of 4PCA with DFT/B3LYP/6-311++G(d,p) level caused by the shifts of Osbnd H and Cdbnd O bands in the vibrational spectra of 4PCA were also studied. Moreover, the spectroscopic and theoretical results were compared with the corresponding properties for monomeric and dimeric structures of 4PCA. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies also confirm that charge transfer occurs within the molecule. NBO analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. The detailed vibrational assignments were performed with the HF and DFT calculations, and the potential energy distribution (PED) was obtained by the Vibrational Energy Distribution Analysis (VEDA4) program.

  4. Global approach for the validation of an in-line Raman spectroscopic method to determine the API content in real-time during a hot-melt extrusion process.

    Science.gov (United States)

    Netchacovitch, L; Thiry, J; De Bleye, C; Dumont, E; Cailletaud, J; Sacré, P-Y; Evrard, B; Hubert, Ph; Ziemons, E

    2017-08-15

    Since the Food and Drug Administration (FDA) published a guidance based on the Process Analytical Technology (PAT) approach, real-time analyses during manufacturing processes are in real expansion. In this study, in-line Raman spectroscopic analyses were performed during a Hot-Melt Extrusion (HME) process to determine the Active Pharmaceutical Ingredient (API) content in real-time. The method was validated based on a univariate and a multivariate approach and the analytical performances of the obtained models were compared. Moreover, on one hand, in-line data were correlated with the real API concentration present in the sample quantified by a previously validated off-line confocal Raman microspectroscopic method. On the other hand, in-line data were also treated in function of the concentration based on the weighing of the components in the prepared mixture. The importance of developing quantitative methods based on the use of a reference method was thus highlighted. The method was validated according to the total error approach fixing the acceptance limits at ±15% and the α risk at ±5%. This method reaches the requirements of the European Pharmacopeia norms for the uniformity of content of single-dose preparations. The validation proves that future results will be in the acceptance limits with a previously defined probability. Finally, the in-line validated method was compared with the off-line one to demonstrate its ability to be used in routine analyses. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Spectroscopic investigations (FT-IR & FT-Raman) and molecular docking analysis of 6-[1-methyl-4-nitro-1H-imidazol-5-yl) sulfonyl]-7H-purine

    Science.gov (United States)

    Prasath, M.; Govindammal, M.; Sathya, B.

    2017-10-01

    The Azathioprine is used as anticancer agent. Azathioprine is chemically called 6-[1-methyl-4-nitro-1H-imidazol-5-yl) sulfonyl]-7H-purine (6M4N5P). The vibrational analysis of the 6M4N5P compound was carried out by using FT-IR and FT-Raman spectroscopic techniques and compared with aspects. The optimized geometry, frequency and intensity of the vibrational bands of 6M4N5P were obtained from the HF and DFT methods with 6-31G (d,p) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The calculated Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energies show that charge transfer occur within the molecule. MEP (Molecular Electrostatic Potential) is very useful in the investigation of the charge distributions and molecular structure. The molecule orbital contributions were determined by using the total density of states (TDOS). A molecular docking analysis has been carried out to understand the conformational change and electrostatic properties of 6M4N5P in the active site of Rac1-Receptor.

  6. Raman Microscopy: A Noninvasive Method to Visualize the Localizations of Biomolecules in the Cornea.

    Science.gov (United States)

    Kaji, Yuichi; Akiyama, Toshihiro; Segawa, Hiroki; Oshika, Tetsuro; Kano, Hideaki

    2017-11-01

    In vivo and in situ visualization of biomolecules without pretreatment will be important for diagnosis and treatment of ocular disorders in the future. Recently, multiphoton microscopy, based on the nonlinear interactions between molecules and photons, has been applied to reveal the localizations of various molecules in tissues. We aimed to use multimodal multiphoton microscopy to visualize the localizations of specific biomolecules in rat corneas. Multiphoton images of the corneas were obtained from nonlinear signals of coherent anti-Stokes Raman scattering, third-order sum frequency generation, and second-harmonic generation. The localizations of the adhesion complex-containing basement membrane and Bowman layer were clearly visible in the third-order sum frequency generation images. The fine structure of type I collagen was observed in the corneal stroma in the second-harmonic generation images. The localizations of lipids, proteins, and nucleic acids (DNA/RNA) was obtained in the coherent anti-Stokes Raman scattering images. Imaging technologies have progressed significantly and been applied in medical fields. Optical coherence tomography and confocal microscopy are widely used but do not provide information on the molecular structure of the cornea. By contrast, multiphoton microscopy provides information on the molecular structure of living tissues. Using this technique, we successfully visualized the localizations of various biomolecules including lipids, proteins, and nucleic acids in the cornea. We speculate that multiphoton microscopy will provide essential information on the physiological and pathological conditions of the cornea, as well as molecular localizations in tissues without pretreatment.

  7. Parametrization of optimum filter passbands for rotational Raman temperature measurements.

    Science.gov (United States)

    Hammann, Eva; Behrendt, Andreas

    2015-11-30

    We revisit the methodology of rotational Raman temperature measurements covering both lidar and non-range-resolved measurements, e.g., for aircraft control. The results of detailed optimization calculations are presented for the commonly used extraction of signals from the anti-Stokes branch. Different background conditions and realistic shapes of the filter transmission curves are taken into account. Practical uncertainties of the central passbands and widths are discussed. We found a simple parametrization for the optimum filter passband shifts depending on the atmospheric temperature range of interest and the background. The approximation errors of this parametrization are smaller than 2% for temperatures between 200 and 300 K and smaller than 4% between 180 and 200 K.

  8. Raman spectroscopic and low-temperature calorimetric investigation of the low-energy vibrational dynamics of hen egg-white lysozyme

    Science.gov (United States)

    Crupi, C.; D'Angelo, G.; Wanderlingh, U.; Vasi, C.

    2011-05-01

    The low-frequency vibrational dynamics of chicken hen egg-white lysozyme were investigated using Raman spectroscopy and low-temperature calorimetry. An amorphous-like behaviour of low-frequency dynamics was observed in this protein. By using inelastic light scattering data and resorting to a fitting procedure, the low-temperature specific heat trend was theoretically reproduced, confirming that, as in disordered systems, the same low-energy excitations give rise to the observed anomalies in low-frequency vibrational and low-temperature thermal properties. A further study of polarised and depolarised Raman spectra has allowed us to infer information about the symmetry of these modes. The frequency dependence of the light-vibrational coupling constant has also been analysed.

  9. Density functional theory, restricted Hartree-Fock simulations and FTIR, FT-Raman and UV-Vis spectroscopic studies on lamotrigine.

    Science.gov (United States)

    Ramya, T; Gunasekaran, S; Ramkumaar, G R

    2013-10-01

    The Fourier Transform Infrared (FTIR) and FT Raman spectra of lamotrigine have been recorded in the region 4000-450 cm(-1) and 4000-50 cm(-1), respectively. The title compound is used as Antiepileptic drug. The optimized geometry, frequency, and intensities of the vibrational bands of the lamotrigine were obtained by Density Functional Theory (DFT) using B3LYP/631G** basis set and ab initio method at the restricted Hartree Fock/6-31** level. The harmonic vibrational frequencies, Natural population analysis, HOMO-LUMO energy gap, infra red intensities and Raman scattering activities, force constant were calculated by DFT and RHF methods. The quality of lamotrigine under different storage containers were analyzed using UV-Vis spectral technique. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Thermal, conductivity, NMR, and Raman spectroscopic measurements and phase diagram of the Cs2S2O7-CsHSO4 system

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Hama, Hind; Lapina, Olga

    2003-01-01

    thermodynamic properties of the pure compounds and the heat of liquid-liquid mixing measured for X(CsHSO4) = 0.5 and 1.0. Cs-113 and O-17 NMR spectra and Raman spectra of the liquid Cs2S2O7-CsHSO4 system indicate the presence of a temperature sensitive equilibrium 2HSO(4) reversible arrow S2O72- + H2O Where...

  11. Thermal degradation of polyaniline films prepared in solutions of strong and weak acids and in water – FTIR and Raman spectroscopic studies

    Czech Academy of Sciences Publication Activity Database

    Šeděnková, Ivana; Trchová, Miroslava; Stejskal, Jaroslav

    2008-01-01

    Roč. 93, č. 12 (2008), s. 2147-2157 ISSN 0141-3910 R&D Projects: GA ČR GA202/06/0419; GA ČR GA203/08/0686 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * infrared spectroscopy * Raman spectroscopy * conducting polymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.320, year: 2008

  12. Quantum mechanical, spectroscopic studies (FT-IR, FT-Raman, NMR, UV) and normal coordinates analysis on 3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide

    Science.gov (United States)

    Muthu, S.; Uma Maheswari, J.; Sundius, Tom

    2013-05-01

    Famotidine (3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide) is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD). Quantum chemical calculations of the equilibrium geometry of famotidine in the ground state were carried out using density functional theory (DFT/B3LYP) with the 6-311G(d,p) basis set. In addition, harmonic vibrational frequencies, infrared intensities and Raman activities were calculated at the same level of theory. A detailed interpretation of the infrared and Raman spectrum of the drug is also reported. Theoretical simulations of the FT-IR, and FT-Raman spectra of the title compound have been calculated. Good correlations between the experimental 1H and 13C NMR chemical shifts and calculated GIAO shielding tensors were found. The results of the energy and oscillator strength calculations by time-dependent density functional theory (TD-DFT) supplement the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. The dipole moment, linear polarizability and first order hyperpolarizability values were also computed. The linear polarizability and first order hyperpolarizabilities of the studied molecule indicate that the compound is a good candidate for nonlinear optical materials.

  13. Quantum mechanical, spectroscopic studies (FT-IR, FT-Raman, NMR, UV) and normal coordinates analysis on 3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide.

    Science.gov (United States)

    Muthu, S; Uma Maheswari, J; Sundius, Tom

    2013-05-01

    Famotidine (3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide) is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD). Quantum chemical calculations of the equilibrium geometry of famotidine in the ground state were carried out using density functional theory (DFT/B3LYP) with the 6-311G(d,p) basis set. In addition, harmonic vibrational frequencies, infrared intensities and Raman activities were calculated at the same level of theory. A detailed interpretation of the infrared and Raman spectrum of the drug is also reported. Theoretical simulations of the FT-IR, and FT-Raman spectra of the title compound have been calculated. Good correlations between the experimental (1)H and (13)C NMR chemical shifts and calculated GIAO shielding tensors were found. The results of the energy and oscillator strength calculations by time-dependent density functional theory (TD-DFT) supplement the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. The dipole moment, linear polarizability and first order hyperpolarizability values were also computed. The linear polarizability and first order hyperpolarizabilities of the studied molecule indicate that the compound is a good candidate for nonlinear optical materials. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Raman spectroscopy using a spatial heterodyne spectrometer: proof of concept.

    Science.gov (United States)

    Gomer, Nathaniel R; Gordon, Christopher M; Lucey, Paul; Sharma, Shiv K; Carter, J Chance; Angel, S Michael

    2011-08-01

    The use of a spatial heterodyne interferometer-based spectrometer (SHS) for Raman spectroscopy is described. The motivation for this work is to develop a small, rugged, high-resolution ultraviolet (UV) Raman spectrometer that is compatible with pulsed laser sources and that is suitable for planetary space missions. UV Raman is a particular technical challenge for space applications because dispersive (grating) approaches require large spectrographs and very narrow slits to achieve the spectral resolution required to maximize the potential of Raman spectroscopy. The heterodyne approach of the SHS has only a weak coupling of resolution and throughput, so a high-resolution UV SHS can both be small and employ a wide slit to maximize throughput. The SHS measures all optical path differences in its interferogram simultaneously with a detector array, so the technique is compatible with gated detection using pulsed lasers, important to reject ambient background and mitigate fluorescence (already low in the UV) that might be encountered on a planetary surface where samples are uncontrolled. The SHS has no moving parts, and as the spectrum is heterodyned around the laser wavelength, it is particularly suitable for Raman measurements. In this preliminary report we demonstrate the ability to measure visible wavelength Raman spectra of liquid and solid materials using an SHS Raman spectrometer and a visible laser. Spectral resolution and bandpass are also discussed. Separation of anti-Stokes and Stokes Raman bands is demonstrated using two different approaches. Finally spectral bandpass doubling is demonstrated by forming an interference pattern in both directions on the ICCD detector followed by analysis using a two-dimensional Fourier transform.

  15. Implementation of Rotational Raman Channel in Multiwavelength Aerosol Lidar to Improve Measurements of Particle Extinction and Backscattering at 532 NM

    Directory of Open Access Journals (Sweden)

    Veselovskii Igor

    2016-01-01

    Full Text Available We describe a practical implementation of rotational Raman (RR measurements in an existing Mie-Raman lidar to obtain measurements of aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.0% in the 230-300K range making accurate correction for this dependence quite easy. With this upgrade, the NASA/GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics will be given in presentation.

  16. Determination of Sudan I in paprika powder by molecularly imprinted polymers-thin layer chromatography-surface enhanced Raman spectroscopic biosensor.

    Science.gov (United States)

    Gao, Fang; Hu, Yaxi; Chen, Da; Li-Chan, Eunice C Y; Grant, Edward; Lu, Xiaonan

    2015-10-01

    Sudan I is a carcinogenic and mutagenic azo-compound that has been utilized as a common adulterant in spice and spice blends to impart a desirable red color to foods. A novel biosensor combining molecularly imprinted polymers (MIPs), thin layer chromatography (TLC) and surface enhanced Raman spectroscopy (SERS) could determine Sudan I levels in paprika powder to 1 ppm (or 2 ng/spot). Sudan I spiked paprika extracts (spiking levels: 0, 1, 5, 10, 40, 70 and 100 ppm) were prepared. Sudan I imprinted polymers were synthesized by employing the interaction between Sudan I (template) and methacrylic acid (functional monomer), followed by washing to remove Sudan I leaving the Sudan I-binding sites exposed. MIPs were used as a stationary phase for TLC and could selectively retain Sudan I at the original spot with little interference. A gold colloid SERS substrate could enhance Raman intensity for Sudan I in this MIP-TLC system. Principal component analysis plot and partial least squares regression (R(2)=0.978) models were constructed and a linear regression model (R(2)=0.983) correlated spiking levels (5, 10, 40, 70 and 100 ppm) with the peak intensities (721 cm(-1)) of Sudan I SERS spectra. Both separation (30-40s) and detection (1s or 0.1s) were extremely fast by using both commercial bench-top and custom made portable Raman spectrometers. This biosensor can be applied as a rapid, low-cost and reliable tool for screening Sudan I adulteration in foods. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Validation of an in-line Raman spectroscopic method for continuous active pharmaceutical ingredient quantification during pharmaceutical hot-melt extrusion.

    Science.gov (United States)

    Saerens, L; Segher, N; Vervaet, C; Remon, J P; De Beer, T

    2014-01-02

    A calibration model for in-line API determination was developed based on Raman spectra collected during hot-melt extrusion. This predictive model was validated by calculating the accuracy profile based on the analysis results of validation experiments. Furthermore, based on the data of the accuracy profile, the measurement uncertainty was determined. Finally, the robustness of the model was evaluated. A Raman probe was implemented in the die of a twin-screw extruder, to monitor the drug concentration during extrusion of physical mixtures containing 15, 20, 25, 30 and 35% (w/w) metoprolol tartrate (MPT) in Eudragit(®) RS PO, an amorphous copolymer of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, which are present as salts. Several different calibration models for the prediction of the MPT content were developed, based on the use of single spectra or averaged spectra, and using partial least squares (PLS) regression or multivariate curve resolution (MCR). These predictive models were validated by extruding and monitoring mixtures containing 17.5, 22.5, 25.0, 27.5 and 32.5% (w/w) MPT. Each validated concentration was monitored on three different days, by two different operators. The β-expectation tolerance intervals were calculated for each model and for each of the validated MPT concentration levels (β was set at 95%), and acceptance limits were set at 10% (relative bias), indicating that at least 95% of future measurements should not deviate more than 10% from the true value. The only model where these acceptance limits were not exceeded was the MCR model based on averaged Raman spectra. The uncertainty measurements for this model showed that the unknown true value can be found at a maximum of ±7.00% around the measured result, with a confidence level of 95%. The robustness of this model was evaluated via an experimental design varying throughput, screw speed and barrel temperature. The robustness designs showed no

  18. Enhanced Raman spectroscopic study of the coordination chemistry of malononitrile on copper surfaces - Removal of nu(C=N) degeneracy through pi-coordination

    Science.gov (United States)

    Loo, B. H.; Lee, Y. G.; Frazier, D. O.

    1985-01-01

    Surface-enhanced Raman spectroscopy has been used to study the molecular interactions of malononitrile with copper electrode surfaces. The doubly degenerate CN stretching frequency at 2263/cm is removed when malononitrile adsorbs on copper. Two nu(CN) bands are observed at 2096 and 2204/cm at -0.6 V(SCE). The result shows that only one CN group is pi-coordinated with Cu, which contributes to the observed large shift (-167/cm) in nu(CN). The other CN group is not coordinated to the metal surface.

  19. Calibration transfer of a Raman spectroscopic quantification method from at-line to in-line assessment of liquid detergent compositions.

    Science.gov (United States)

    Brouckaert, D; Uyttersprot, J-S; Broeckx, W; De Beer, T

    2017-06-08

    The industrial production of liquid detergent compositions entails delicate balance of ingredients and process steps. In order to assure high quality and productivity in the manufacturing line, process analytical technology tools such as Raman spectroscopy are to be implemented. Marked chemical specificity, negligible water interference and high robustness are ascribed to this process analytical technique. Previously, at-line calibration models have been developed for determining the concentration levels of the being studied liquid detergents main ingredients from Raman spectra. A strategy is now proposed to transfer such at-line developed regression models to an in-line set-up, allowing real-time dosing control of the liquid detergent composition under production. To mimic in-line manufacturing conditions, liquid detergent compositions are created in a five-liter vessel with an overhead mixer. Raman spectra are continuously acquired by pumping the detergent under production via plastic tubing towards a Raman superhead probe, which is incorporated into a metal frame with a sapphire window facing the detergent fluid. Two at-line developed partial least squares (PLS) models are aimed at transferring, predicting the concentration of surfactant 1 and polymer 2 in the examined liquid detergent composition. A univariate slope/bias correction (SBC) is investigated, next to three well-acknowledged multivariate transformation methods: direct, piecewise and double-window piecewise direct standardization. Transfer is considered successful when the magnitude of the validation sets root mean square error of prediction (RMSEP) is similar to or smaller than the corresponding at-line prediction error. The transferred model offering the most promising outcome is further subjected to an exhaustive statistical evaluation, in order to appraise the applicability of the suggested calibration transfer method. Interval hypothesis tests are thereby performed for method comparison. It is

  20. ATR-FTIR and Raman spectroscopic investigation of the electroporation-mediated transdermal delivery of a nanocarrier system containing an antitumour drug.

    Science.gov (United States)

    Balázs, Boglárka; Sipos, Péter; Danciu, Corina; Avram, Stefana; Soica, Codruta; Dehelean, Cristina; Varju, Gábor; Erős, Gábor; Budai-Szűcs, Mária; Berkó, Szilvia; Csányi, Erzsébet

    2016-01-01

    The aim of the present work was the optimization of the transdermal delivery of a lyotropic liquid crystal genistein-based formulation (LLC-GEN). LLC was chosen as medium in view of the poor solubility of GEN in water. Membrane diffusion and penetration studies were carried out with a Franz diffusion cell, through a synthetic membrane in vitro, a chick chorioallantoic membrane ex ovo, and ex vivo excised human epidermis. Thereafter, LLC-GEN was combined with electroporation (EP) to enhance the transdermal drug delivery. The synergistic effect of EP was verified by in vivo ATR-FTIR and ex vivo Raman spectroscopy on hairless mouse skin.

  1. High precision stress measurements in semiconductor structures by Raman microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Uhlig, Benjamin

    2009-07-01

    Stress in silicon structures plays an essential role in modern semiconductor technology. This stress has to be measured and due to the ongoing miniaturization in today's semiconductor industry, the measuring method has to meet certain requirements. The present thesis deals with the question how Raman spectroscopy can be used to measure the state of stress in semiconductor structures. In the first chapter the relation between Raman peakshift and stress in the material is explained. It is shown that detailed stress maps with a spatial resolution close to the diffraction limit can be obtained in structured semiconductor samples. Furthermore a novel procedure, the so called Stokes-AntiStokes-Difference method is introduced. With this method, topography, tool or drift effects can be distinguished from stress related influences in the sample. In the next chapter Tip-enhanced Raman Scattering (TERS) and its application for an improvement in lateral resolution is discussed. For this, a study is presented, which shows the influence of metal particles on the intensity and localization of the Raman signal. A method to attach metal particles to scannable tips is successfully applied. First TERS scans are shown and their impact on and challenges for high resolution stress measurements on semiconductor structures is explained. (orig.)

  2. DFT-assisted spectroscopic characterization of pyrazosulfuron-ethyl: FT-Raman, FTIR and UV-vis studies of a sulfonyl urea herbicide

    Science.gov (United States)

    Monicka, J. Clemy; James, C.

    2014-10-01

    Raman and IR spectra of pyrazosulfuron-ethyl have been reported here, and it is shown that the spectra has been fully interpreted in terms of assigning normal modes to the various spectral features by using density functional theory calculations. The Raman bands observed for PY in solid phase are characteristic for the carbonyl group, Csbnd C, Csbnd H and Nsbnd H stretching and deformation vibrations. The dimer structure of PY was optimized, including the Nsbnd H…N and Csbnd H…O intermolecular interactions. Stability of the molecule arising from hyperconjugative interactions leading to its bioactivity and charge delocalization have been analyzed using natural bond orbital analysis. Spectral analysis reveals the substantial effect of non-bonding interaction, conjugation and induction effects in the molecule which in turn influences the bioactivity of the compound. Red shifting of (∼94 cm-1) Nsbnd H stretching band substantiates the presence of strong Nsbnd H…N intramolecular hydrogen bonding in the molecule. The aromatic behavior of pyrimidine and pyrazole ring has been calculated using the HOMA method.

  3. Combined experimental and quantum chemical studies on spectroscopic (FT-IR, FT-Raman, UV-Vis, and NMR) and structural characteristics of quinoline-5-carboxaldehyde

    Science.gov (United States)

    Kumru, Mustafa; Altun, Ahmet; Kocademir, Mustafa; Küçük, Vesile; Bardakçı, Tayyibe; Şaşmaz, İbrahim

    2016-12-01

    Comparative experimental and theoretical studies have been performed on the structure and spectral (FT-IR, FT-Raman, UV-Vis and NMR) features of quinoline-5-carboxaldehyde. Quantum chemical calculations have been carried out at Hartree-Fock and density functional B3LYP levels with the triple-zeta 6-311++G** basis set. Two stable conformers of quinoline-5-carboxaldehyde arising from the orientation of the carboxaldehyde moiety have been located at the room temperature. The energetic separation of these conformers is as small as 2.5 kcal/mol with a low transition barrier (around 9 kcal/mol). Therefore, these conformers are expected to coexist at the room temperature. Several molecular characteristics of quinoline-5-carboxaldehyde obtained through B3LYP and time-dependent B3LYP calculations, such as conformational stability, key geometry parameters, vibrational frequencies, IR and Raman intensities, UV-Vis vertical excitation energies and the corresponding oscillator strengths have been analyzed. The 1H and 13C NMR chemical shifts of quinoline-5-carboxaldehyde were also investigated.

  4. QM/MM methodology, docking and spectroscopic (FT-IR/FT-Raman, NMR, UV) and Fukui function analysis on adrenergic agonist.

    Science.gov (United States)

    Uma Maheswari, J; Muthu, S; Sundius, Tom

    2015-02-25

    The Fourier transform infrared, FT-Raman, UV and NMR spectra of Ternelin have been recorded and analyzed. Harmonic vibrational frequencies have been investigated with the help of HF with 6-31G (d,p) and B3LYP with 6-31G (d,p) and LANL2DZ basis sets. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. The polarizability (α) and the first hyperpolarizability (β) values of the investigated molecule have been computed using DFT quantum mechanical calculations. Stability of the molecule arising from hyper conjugative interactions, and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in Ternelin. Finally the calculated results were compared to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra. Molecular docking studies have been carried out in the active site of Ternelin and reactivity with ONIOM was also investigated. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Application of spectroscopic methods for identification (FT-IR, Raman spectroscopy) and determination (UV, EPR) of quercetin-3-O-rutinoside. Experimental and DFT based approach.

    Science.gov (United States)

    Paczkowska, Magdalena; Lewandowska, Kornelia; Bednarski, Waldemar; Mizera, Mikołaj; Podborska, Agnieszka; Krause, Anna; Cielecka-Piontek, Judyta

    2015-04-05

    Vibrational (FT-IR, Raman) and electronic (UV, EPR) spectral measurements were performed for an analysis of rutin (quercetin-3-O-rutinoside) obtained from Rutaofficinalis. The identification of rutin was done with the use of FT-IR and Raman spectra. Those experimental spectra were determined with the support of theoretical calculations based on a DFT method with the B3LYP hybrid functional and 6-31G(d,p) basis set. The application of UV and EPR spectra was found to be a suitable analytical approach to the evaluation of changes in rutin exposed to certain physicochemical factors. Differences in absorbance observed in direct UV spectra were used to monitor changes in the concentration of rutin in degraded samples. Spectra of electron paramagnetic resonance allowed studying the process of free-radical quenching in rutin following its exposure to light. The molecular electrostatic potential (MEP) and frontier molecular orbitals (LUMO-HOMO) were also determined in order to predict structural changes and reactive sites in rutin. Copyright © 2015. Published by Elsevier B.V.

  6. A micro-Raman spectroscopic investigation of leukemic U-937 cells treated with Crotalaria agatiflora Schweinf and the isolated compound madurensine

    Science.gov (United States)

    le Roux, Karlien; Prinsloo, Linda C.; Hussein, Ahmed A.; Lall, Namrita

    In South Africa traditional medicine plays an important role in primary health care and therefore it is very important that the medicinal use of plants is scientifically tested for toxicity and effectiveness. It was established that the ethanolic extract of the leaves of Crotalaria agatiflora, as well as the isolated compound madurensine, is moderately toxic against leukemic U-937 cells. Light microscopic investigations indicated that symptoms of cell death are induced during treatments, but flow cytometry analysis of treated cells, using annexin-V and propidium iodide, showed that apoptosis and necrosis are insignificantly induced. The Raman results suggested that protein extraction and DNA melting occur in the cells during treatment with the ethanolic extracts (IC50 value 73.9 μg/mL), drastically changing the molecular content of the cells. In contrast, treatment with madurensine (IC50 value 136.5 μg/mL), an isolated pyrrolizidine alkaloid from the ethanolic extract of the leaves, did not have the same effect. The results are also compared to that of cells treated with actinomycin D, a compound known to induce apoptosis. The investigation showed that micro-Raman spectroscopy has great promise to be used for initial screening of samples to determine the effects of different treatments on cancerous cell lines together with conventional methods. The results highlight the fact that for many natural products used for medicinal purposes, the therapeutic effect of the crude plant extract tends to be significantly more effective than the particular action of its individual constituents.

  7. Effects of laser photherapy on bone defects grafted with mineral trioxide aggregate, bone morphogenetic proteins, and guided bone regeneration: a Raman spectroscopic study.

    Science.gov (United States)

    Pinheiro, Antonio L B; Aciole, Gilberth T S; Cangussú, Maria Cristina T; Pacheco, Marcos T T; Silveira, Landulfo

    2010-12-15

    We have used Raman analysis to assess bone healing on different models. Benefits on the isolated or combined use of mineral trioxide aggregate, bone morphogenetic proteins, guided bone regeneration and laser on bone repair have been reported, but not their combination. We studied peaks of hydroxyapatite and CH groups on defects grafted with MTA, treated or not with laser, BMPs, and GBR. Ninety rats were divided in 10 groups each, subdivided into three subgroups. Laser (λ850 nm) was applied at every other day for 2 weeks. Raman readings were taken at the surface of the defect. Statistical analysis (CHA) showed significant differences between all groups (p = 0.001) and between Group II and all other (p bone is because of increased secretion of calcium hydroxyapatite (CHA) that is indicative of greater calcification and resistance of the bone. We conclude that the association of the MTA with laser phototherapy (LPT) and/or not with GBR resulted in a better bone repair. The use of the MTA associated to IR LPT resulted in a more advanced and quality bone repair. Copyright © 2010 Wiley Periodicals, Inc.

  8. The spectroscopic (FT-IR, FT-Raman, UV and NMR) first order hyperpolarizability and HOMO-LUMO analysis of dansyl chloride.

    Science.gov (United States)

    Karabacak, M; Cinar, M; Kurt, M; Poiyamozhi, A; Sundaraganesan, N

    2014-01-03

    The solid phase FT-IR and FT-Raman spectra of dansyl chloride (DC) have been recorded in the regions 400-4000 and 50-4000 cm(-1), respectively. The spectra have been interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule has been optimized and the structural characteristics have been determined by density functional theory (B3LYP) method with 6-311++G(d,p) as basis set. The vibrational frequencies were calculated for most stable conformer and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra have also been predicted from the calculated intensities. (1)H and (13)CNMR spectra were recorded and (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Visible spectrum of the compound was recorded in the region 200-600 nm and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Exploiting the benefit of S0→ T1excitation in triplet-triplet annihilation upconversion to attain large anti-stokes shifts: tuning the triplet state lifetime of a tris(2,2'-bipyridine) osmium(ii) complex.

    Science.gov (United States)

    Liu, Dongyi; Zhao, Yingjie; Wang, Zhijia; Xu, Kejing; Zhao, Jianzhang

    2018-03-07

    Os(ii) complexes are particularly interesting for triplet-triplet annihilation (TTA) upconversion, due to the strong direct S 0 → T 1 photoexcitation, as in this way, energy loss is minimized and large anti-Stokes shift can be achieved for TTA upconversion. However, Os(bpy) 3 has an intrinsic short T 1 state lifetime (56 ns), which is detrimental for the intermolecular triplet-triplet energy transfer (TTET), one of the crucial steps in TTA upconversion. In order to prolong the triplet state lifetime, we prepared an Os(ii) tris(bpy) complex with a Bodipy moiety attached, so that an extended T 1 state lifetime is achieved by excited state electronic configuration mixing or triplet state equilibrium between the coordination center-localized state ( 3 MLCT state) and Bodipy ligand-localized state ( 3 IL state). With steady-state and time-resolved transient absorption/emission spectroscopy, we proved that the 3 MLCT is slightly above the 3 IL state (by 0.05 eV), and the triplet state lifetime was prolonged by 31-fold (from 56 ns to 1.73 μs). The TTA upconversion quantum yield was increased by 4-fold as compared to that of the unsubstituted Os(ii) complex.

  10. Development of laser Raman and x-ray photoelectron spectroscopic parameters as an additional thermal maturity indicator to the conodont alteration index

    International Nuclear Information System (INIS)

    Marshall, C.P.; Wilson, M.A.

    1999-01-01

    Full text: Laser Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) was applied in an attempt to quantify and elucidate the chemical transformations of the conodont alteration index (CAI) in artificially matured conodonts. Coniform elements of the genus Drepanodus from the Ordovician Emanuel Formation and pectiniform elements of the genus Polygnathus from the Devonian Napier Formation, both from the Canning Basin were used in this investigation. Samples where specifically chosen to study the effects of genus, element morphology, geological age, lithology and depositional environment upon the CAI. The first order Raman spectra (900-1800 cm-1) of both sets of conodonts show three bands. These are assigned to apatite at 965 cm-1, D band (defects present in the structural units and disorder) at 1345 cm-1 and the G band (carbon-carbon in plane stretching vibration or structural ordered carbon) at 1600 cm-1. The Raman spectra recorded for both sample sets, CAI range of 1-7 are characteristic of poorly/ highly disordered carbon within the conodont organic matter. Further more, the D band becomes progressively narrower and more intense the higher the thermal treatment. The G band becomes narrower until CAI 4 and after that has no systematic change apart from the intensity decreasing with temperature. The most noteworthy spectral characteristic in relation to thermal maturity is the clearly defined linear trend of decreasing D band line-width with increasing rank. The carbon 1s photoelectron regions acquired from both sample sets contain three peaks. These peaks are assigned to carbon bonded to sp3 and sp2 hybridized carbon (284.7 eV), alcohol (287.2 eV) and carboxyl (288.3 eV) functional groups. With increasing thermal treatment all the carbon constituents show a linear decrease in abundance. The poorly/ highly disordered carbon shows no progressive ordering with increasing thermal treatment. This is also in agreement with the XPS results, in which the aliphatic

  11. The spectroscopic (FT-IR, FT-Raman, UV) and first order hyperpolarizability, HOMO and LUMO analysis of 3-aminobenzophenone by density functional method.

    Science.gov (United States)

    Karabacak, M; Kurt, M; Cinar, M; Ayyappan, S; Sudha, S; Sundaraganesan, N

    2012-06-15

    In this work, experimental and theoretical study on the molecular structure and the vibrational spectra of 3-aminobenzophenone (3-ABP) is presented. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the region of 400-4000 cm(-1) and with Fourier Transform Raman spectrum in the region of 50-4000 cm(-1). Complete vibrational assignments, analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Micro-Raman and FT-IR spectroscopic studies of ceramic shards excavated from ancient Stratonikeia city at Eskihisar village in West-South Turkey

    Science.gov (United States)

    Bahçeli, Semiha; Güleç, Gamze; Erdoğan, Hasan; Söğüt, Bilal

    2016-02-01

    In this study, micro-Raman and Fourier transformed infrared (FT-IR) spectroscopies, X-ray diffraction (XRD) and scanning electron microscope with energy dispersive X-ray (SEM-EDX) were used to characterize the mineralogical structures of pigments of four ceramic fragments in which one of them belongs to Hellenistic period (1st - IVth century BC) and other three ceramic shards belong to Early Rome (IVth century BC- 1st century AD) excavated from Stratonikeia ancient city. In the results of investigations on these four ceramic fragments, the various phases were identified: quartz, kaolinite, albit (or Na-feldspar), calcite, anastase, hematite and magnetite. Furthermore, the obtained findings indicate that firing temperature is about 800-850 °C for all the shards.

  13. Effects of LED phototherapy on bone defects grafted with MTA, bone morphogenetic proteins and guided bone regeneration: a Raman spectroscopic study.

    Science.gov (United States)

    Pinheiro, Antonio L B; Soares, Luiz G P; Cangussú, Maria Cristina T; Santos, Nicole R S; Barbosa, Artur Felipe S; Silveira Júnior, Landulfo

    2012-09-01

    We studied peaks of calcium hydroxyapatite (CHA) and protein and lipid CH groups in defects grafted with mineral trioxide aggregate (MTA) treated or not with LED irradiation, bone morphogenetic proteins and guided bone regeneration. A total of 90 rats were divided into ten groups each of which was subdivided into three subgroups (evaluated at 15, 21 and 30 days after surgery). Defects were irradiated with LED light (wavelength 850 ± 10 nm) at 48-h intervals for 15 days. Raman readings were taken at the surface of the defects. There were no statistically significant differences in the CHA peaks among the nonirradiated defects at any of the experimental time-points. On the other hand, there were significant differences between the defects filled with blood clot and the irradiated defects at all time-points (p LED light irradiation improves the deposition of CHA in healing bone grafted or not with MTA.

  14. The spectroscopic (FT-IR, FT-IR gas phase, FT-Raman and UV) and NBO analysis of 4-Hydroxypiperidine by density functional method.

    Science.gov (United States)

    Sebastian, S; Sundaraganesan, N

    2010-03-01

    In this work, we report a combined experimental and theoretical study on molecular structure, vibrational spectra, NBO and UV-spectral analysis of 4-Hydroxypiperidine (4-HP). The FT-IR solid phase (4000-400 cm(-1)), FT-IR gas phase (5000-400 cm(-1)) and FT-Raman spectra (3500-50 cm(-1)) of 4-HP was recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of 4-HP in the ground-state have been calculated by using the density functional methods (BLYP, B3LYP) with 6-311G (d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). Stability of the molecule arising from hyperconjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the sigma* antibonding orbitals and E (2) energies confirms the occurrence of ICT (Intra-molecular Charge Transfer) within the molecule. The UV spectrum was measured in ethanol solution. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally the calculation results were applied to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra. Copyright 2009 Elsevier B.V. All rights reserved.

  15. Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation and NLO, HOMO-LUMO, NBO analysis of organic 2,4,5-trichloroaniline.

    Science.gov (United States)

    Govindarajan, M; Karabacak, M; Periandy, S; Tanuja, D

    2012-11-01

    In this work, the experimental and theoretical study on the molecular structure and vibrational spectra of 2,4,5-trichloroaniline (C(6)H(4)NCl(3), abbreviated as 2,4,5-TClA) were studied. The FT-IR and FT-Raman spectra were recorded. The molecular geometry and vibrational frequencies in the ground state were calculated by using the Hartree-Fock (HF) and density functional theory (DFT) methods (B3LYP) with 6-311++G(d,p) basis set. Comparison of the observed fundamental vibrational frequencies of 2,4,5-TClA with calculated results by HF and DFT indicates that B3LYP is superior to HF method for molecular vibrational problems. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. The theoretically predicted FT-IR and FT-Raman spectra of the title molecule have been constructed. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and the first hyperpolarizability (β) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results also show that the 2,4,5-TClA molecule may have microscopic nonlinear optical (NLO) behavior with non-zero values. Mulliken atomic charges of 2,4,5-TClA was calculated and compared with aniline and chlorobenzene molecules. The (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Molecular structure, spectroscopic characterization (FT-IR, FT-Raman, UV and NMR), HOMO and LUMO analysis of 3-ethynylthiophene with DFT quantum chemical calculations.

    Science.gov (United States)

    Karabacak, Mehmet; Bilgili, Sibel; Mavis, Tugba; Eskici, Mustafa; Atac, Ahmet

    2013-11-01

    In this work, FT-IR, FT-Raman, UV and NMR spectra of 3-ethynylthiophene (3-ETP, C6H4S) were carried out by using density functional theory DFT/B3LYP method with the 6-311++G(d,p), 6-311+G(d,p), 6-311G(d,p), 6-31++G(d,p), 6-31+G(d,p), 6-31G(d,p) basis sets. FT-IR and FT-Raman spectra were recorded in the regions of 3500-400cm(-1) and 3500-50cm(-1), respectively. The geometrical parameters, energies and wavenumbers were obtained and the complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The (1)H, (13)C and HMQC ((1)H-(13)C correlation) NMR spectra in chloroform (CDCl3) were recorded and calculated. The UV spectrum of investigated compound were recorded in the region of 200-400nm in ethanol solution. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies were performed by DFT/B3LYP approach and the results were compared with experimental observations. The thermodynamic properties such zero-point vibrational energy, thermal energy, specific heat capacity, rotational constants, entropy, and dipole moment of the studied compound were calculated. As a result, the calculated results were compared with the observed data and found to be in good agreement. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Molecular structure, vibrational spectroscopic (FT-IR, FT-Raman), UV and NBO analysis of 2-chlorobenzonitrile by density functional method.

    Science.gov (United States)

    Krishnan, Akhil R; Saleem, H; Subashchandrabose, S; Sundaraganesan, N; Sebastain, S

    2011-02-01

    In this work, we will report a combined experimental and theoretical study on molecular structure, vibrational spectra, NBO and UV spectral analysis of 2-chlorobenzonitrile (2-ClBN). The FT-IR solid phase (4000-400 cm(-1)), and FT-Raman spectra (3500-50 cm(-1)) of 2-ClBN was recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of 2-ClBN in the ground state have been calculated by using the density functional methods (BLYP, B3LYP) with 6-31G(d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the σ* and π* anti bonding orbitals and E2 energies confirms the occurrence of ICT (Intra molecular Charge Transfer) within the molecule. The UV spectrum was measured in ethanol solution. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. Finally calculated results were applied to simulated Infrared and Raman spectra of the title compound which show good agreement with observed spectra. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

    Science.gov (United States)

    Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

    2015-03-15

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  19. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations

    Science.gov (United States)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-03-01

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The 13C and 1H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

  20. Raman spectroscopic measurements of CO2 density: Experimental calibration with high-pressure optical cell (HPOC) and fused silica capillary capsule (FSCC) with application to fluid inclusion observations

    Science.gov (United States)

    Wang, X.; Chou, I-Ming; Hu, W.; Burruss, Robert; Sun, Q.; Song, Y.

    2011-01-01

    Raman spectroscopy is a powerful method for the determination of CO2 densities in fluid inclusions, especially for those with small size and/or low fluid density. The relationship between CO2 Fermi diad split (Δ, cm−1) and CO2 density (ρ, g/cm3) has been documented by several previous studies. However, significant discrepancies exist among these studies mainly because of inconsistent calibration procedures and lack of measurements for CO2fluids having densities between 0.21 and 0.75 g/cm3, where liquid and vapor phases coexist near room temperature.In this study, a high-pressure optical cell and fused silica capillary capsules were used to prepare pure CO2 samples with densities between 0.0472 and 1.0060 g/cm3. The measured CO2 Fermi diad splits were calibrated with two well established Raman bands of benzonitrile at 1192.6 and 1598.9 cm−1. The relationship between the CO2 Fermi diad split and density can be represented by: ρ = 47513.64243 − 1374.824414 × Δ + 13.25586152 × Δ2 − 0.04258891551 × Δ3(r2 = 0.99835, σ = 0.0253 g/cm3), and this relationship was tested by synthetic fluid inclusions and natural CO2-rich fluid inclusions. The effects of temperature and the presence of H2O and CH4 on this relationship were also examined.

  1. Conformational stability, spectroscopic (FT-IR, FT-Raman and UV-Vis) analysis, NLO, NBO, FMO and Fukui function analysis of 4-hexylacetophenone by density functional theory.

    Science.gov (United States)

    Saravanan, S; Balachandran, V

    2015-03-05

    The experimental and theoretical study on the structures and vibrations of 4-hexylacetophenone (abbreviated as 4HAP) are presented. The FT-IR and FT-Raman spectra of the title compound have been recorded in the region 4000-400cm(-1) and 3500-100cm(-1) respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) method with 6-311++G(d,p) basis set. The most stable conformer of 4HAP is identified from the computational results. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMEF). The linear polarizability (α) and the first hyperpolarizability (βtot) values of the investigated molecule have been computed using B3LYP and LSDA with 6-311++G(d,p) basis set. Stability of the molecule arising from hyper conjugative interaction and charge transfer delocalization has been analyzed using natural bond orbital (NBO) analysis. The molecule orbital contributions are studied by density of energy states (DOSs). UV-Vis spectrum and effects of solvents have been discussed effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach. Fukui function and Mulliken analysis on atomic charges of the title compound have been calculated. Finally, electrophilic and nucleophilic descriptors of the title molecule have been calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Calibration transfer of a Raman spectroscopic quantification method for the assessment of liquid detergent compositions between two at-line instruments installed at two liquid detergent production plants.

    Science.gov (United States)

    Brouckaert, D; Uyttersprot, J-S; Broeckx, W; De Beer, T

    2017-09-01

    Calibration transfer of partial least squares (PLS) quantification models is established between two Raman spectrometers located at two liquid detergent production plants. As full recalibration of existing calibration models is time-consuming, labour-intensive and costly, it is investigated whether the use of mathematical correction methods requiring only a handful of standardization samples can overcome the dissimilarities in spectral response observed between both measurement systems. Univariate and multivariate standardization approaches are investigated, ranging from simple slope/bias correction (SBC), local centring (LC) and single wavelength standardization (SWS) to more complex direct standardization (DS) and piecewise direct standardization (PDS). The results of these five calibration transfer methods are compared reciprocally, as well as with regard to a full recalibration. Four PLS quantification models, each predicting the concentration of one of the four main ingredients in the studied liquid detergent composition, are aimed at transferring. Accuracy profiles are established from the original and transferred quantification models for validation purposes. A reliable representation of the calibration models performance before and after transfer is thus established, based on β-expectation tolerance intervals. For each transferred model, it is investigated whether every future measurement that will be performed in routine will be close enough to the unknown true value of the sample. From this validation, it is concluded that instrument standardization is successful for three out of four investigated calibration models using multivariate (DS and PDS) transfer approaches. The fourth transferred PLS model could not be validated over the investigated concentration range, due to a lack of precision of the slave instrument. Comparing these transfer results to a full recalibration on the slave instrument allows comparison of the predictive power of both Raman

  3. Raman spectrum of asphaltene

    KAUST Repository

    Abdallah, Wael A.

    2012-11-05

    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  4. Local structure of amorphous Ag5In5Sb60Te30 and In3SbTe2 phase change materials revealed by X-ray photoelectron and Raman spectroscopic studies

    Science.gov (United States)

    Sahu, Smriti; Manivannan, Anbarasu; Shaik, Habibuddin; Mohan Rao, G.

    2017-07-01

    Reversible switching between highly resistive (binary "0") amorphous phase and low resistive (binary "1") crystalline phase of chalcogenide-based Phase Change Materials is accredited for the development of next generation high-speed, non-volatile, data storage applications. The doped Sb-Te based materials have shown enhanced electrical/optical properties, compared to Ge-Sb-Te family for high-speed memory devices. We report here the local atomic structure of as-deposited amorphous Ag5In5Sb60Te30 (AIST) and In3SbTe2 (IST) phase change materials using X-ray photoelectron and Raman spectroscopic studies. Although AIST and IST materials show identical crystallization behavior, they differ distinctly in their crystallization temperatures. Our experimental results demonstrate that the local environment of In remains identical in the amorphous phase of both AIST and IST material, irrespective of its atomic fraction. In bonds with Sb (˜44%) and Te (˜56%), thereby forming the primary matrix in IST with a very few Sb-Te bonds. Sb2Te constructs the base matrix for AIST (˜63%) along with few Sb-Sb bonds. Furthermore, an interesting assimilation of the role of small-scale dopants such as Ag and In in AIST, reveals rare bonds between themselves, while showing selective substitution in the vicinity of Sb and Te. This results in increased electronegativity difference, and consequently, the bond strength is recognized as the factor rendering stability in amorphous AIST.

  5. Nondestructive spectroscopic characterization of building materials

    Science.gov (United States)

    Kassu, Aschalew; Walker, Lauren; Sanders, Rachel; Farley, Carlton; Mills, Jonathan; Sharma, Anup

    2017-04-01

    The purpose of this research project is to demonstrate the application of Raman spectroscopy technique for characterization and identification of the distinct Raman signatures of construction materials. The results reported include the spectroscopic characterization of building materials using compact Raman system with 785 nm wavelength laser. The construction materials studied include polyblend sanded grout, fire barrier sealant, acrylic latex caulk plus and white silicone. It is found that, both fire barrier sealant and acrylic latex caulk plus has a prominent Raman band at 1082 cm-1, and three minor Raman signatures located at 275, 706 and 1436 cm-1. On the other hand, sand grout has three major Raman bands at 1265, 1368 and 1455 cm-1, and four minor peaks at 1573, 1683, 1762, and 1868 cm-1. White silicone, which is a widely used sealant material in construction industry, has two major Raman bands at 482 and 703 cm-1, and minor Raman characteristic bands at 783 and 1409 cm-1.

  6. Raman spectroscopy in pharmaceutical product design

    DEFF Research Database (Denmark)

    Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

    2015-01-01

    molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant...... application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed....

  7. Raman-based imaging uncovers the effects of alginate hydrogel implants in spinal cord injury

    Science.gov (United States)

    Galli, Roberta; Tamosaityte, Sandra; Koch, Maria; Sitoci-Ficici, Kerim H.; Later, Robert; Uckermann, Ortrud; Beiermeister, Rudolf; Gelinsky, Michael; Schackert, Gabriele; Kirsch, Matthias; Koch, Edmund; Steiner, Gerald

    2015-07-01

    The treatment of spinal cord injury by using implants that provide a permissive environment for axonal growth is in the focus of the research for regenerative therapies. Here, Raman-based label-free techniques were applied for the characterization of morphochemical properties of surgically induced spinal cord injury in the rat that received an implant of soft unfunctionalized alginate hydrogel. Raman microspectroscopy followed by chemometrics allowed mapping the different degenerative areas, while multimodal multiphoton microscopy (e.g. the combination of coherent anti-Stokes Raman scattering (CARS), endogenous two-photon fluorescence and second harmonic generation on the same platform) enabled to address the morphochemistry of the tissue at cellular level. The regions of injury, characterized by demyelination and scarring, were retrieved and the distribution of key tissue components was evaluated by Raman mapping. The alginate hydrogel was detected in the lesion up to six months after implantation and had positive effects on the nervous tissue. For instance, multimodal multiphoton microscopy complemented the results of Raman mapping, providing the micromorphology of lipid-rich tissue structures by CARS and enabling to discern lipid-rich regions that contained myelinated axons from degenerative regions characterized by myelin fragmentation and presence of foam cells. These findings demonstrate that Raman-based imaging methods provide useful information for the evaluation of alginate implant effects and have therefore the potential to contribute to new strategies for monitoring degenerative and regenerative processes induced in SCI, thereby improving the effectiveness of therapies.

  8. Spectroscopic (FTIR, FT-Raman, UV and NMR) investigation and NLO, HOMO-LUMO, NBO analysis of 2-Benzylpyridine based on quantum chemical calculations.

    Science.gov (United States)

    Mathammal, R; Sudha, N; Guru Prasad, L; Ganga, N; Krishnakumar, V

    2015-02-25

    In this work, the vibrational characteristics of 2-Benzylpyridine have been investigated. The structure of the molecule has been optimized and the structural characteristics of the molecule have been determined by density functional theory B3LYP method with 6-31G(d,p) basis set. The infrared and Raman spectra have been simulated from calculated intensities. Both the experimental and theoretical vibrational data confirms the presence of functional groups in the title compound. The (1)H and (13)C NMR spectra were recorded and (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital method. UV-Visible spectrum of the title compound was recorded in the region 190-1100 nm and the electronic properties HOMO and LUMO energies were calculated by CIS approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Preparation and characterizations of SnO2 nanopowder and spectroscopic (FT-IR, FT-Raman, UV-Visible and NMR) analysis using HF and DFT calculations.

    Science.gov (United States)

    Ayeshamariam, A; Ramalingam, S; Bououdina, M; Jayachandran, M

    2014-01-24

    In this work, pure and singe phase SnO2 Nano powder is successfully prepared by simple sol-gel combustion route. The photo luminescence and XRD measurements are made and compared the geometrical parameters with calculated values. The FT-IR and FT-Raman spectra are recorded and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (LSDA, B3LYP and B3PW91) theory in bulk phase of SnO2 and are compared with its Nano phase. The vibrational frequency pattern in nano phase gets realigned and the frequencies are shifted up to higher region of spectra when compared with bulk phase. The NMR and UV-Visible spectra are simulated and analyzed. Transmittance studies showed that the HOMO-LUMO band gap (Kubo gap) is reduced from 3.47 eV to 3.04 eV while it is heated up to 800°C. The Photoluminescence spectra of SnO2 powder showed a peak shift towards lower energy side with the change of Kubo gap from 3.73 eV to 3.229 eV for as-prepared and heated up to 800°C. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  10. Quaternary ammonium oxidative demethylation: X-ray crystallographic, resonance Raman, and UV-visible spectroscopic analysis of a Rieske-type demethylase.

    Science.gov (United States)

    Daughtry, Kelly D; Xiao, Youli; Stoner-Ma, Deborah; Cho, Eunsun; Orville, Allen M; Liu, Pinghua; Allen, Karen N

    2012-02-08

    Herein, the structure resulting from in situ turnover in a chemically challenging quaternary ammonium oxidative demethylation reaction was captured via crystallographic analysis and analyzed via single-crystal spectroscopy. Crystal structures were determined for the Rieske-type monooxygenase, stachydrine demethylase, in the unliganded state (at 1.6 Å resolution) and in the product complex (at 2.2 Å resolution). The ligand complex was obtained from enzyme aerobically cocrystallized with the substrate stachydrine (N,N-dimethylproline). The ligand electron density in the complex was interpreted as proline, generated within the active site at 100 K by the absorption of X-ray photon energy and two consecutive demethylation cycles. The oxidation state of the Rieske iron-sulfur cluster was characterized by UV-visible spectroscopy throughout X-ray data collection in conjunction with resonance Raman spectra collected before and after diffraction data. Shifts in the absorption band wavelength and intensity as a function of absorbed X-ray dose demonstrated that the Rieske center was reduced by solvated electrons generated by X-ray photons; the kinetics of the reduction process differed dramatically for the liganded complex compared to unliganded demethylase, which may correspond to the observed turnover in the crystal.

  11. Quantum chemical studies on molecular structure, spectroscopic (IR, Raman, UV-Vis), NBO and HOMO-LUMO analysis of 1-benzyl-3-(2-furoyl) thiourea.

    Science.gov (United States)

    Gil, Diego M; Defonsi Lestard, M E; Estévez-Hernández, O; Duque, J; Reguera, E

    2015-06-15

    Vibrational and electronic spectra for 1-benzyl-3-(2-furoyl) thiourea were calculated by using density functional method (B3LYP) with different basis sets. The complete assignment of all vibrational modes was performed on basis of the calculated frequencies and comparing with the reported IR and Raman spectra for that thiourea derivative. UV-visible absorption spectra of the compound dissolved in methanol were recorded and analyzed using time dependent density functional theory (TD-DFT). The calculated values for the geometrical parameters of the title compound are consistent with the ones reported from XRD studies. The stability of the molecule, related to hyper-conjugative interactions, and electron delocalization were evaluated using natural bond orbital (NBO) analysis. Intra-molecular interactions were studied by AIM approach. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. Molecular electrostatic potential map was performed by the DFT method. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Spectroscopic [FT-IR and FT-Raman] and theoretical [UV-Visible and NMR] analysis on α-Methylstyrene by DFT calculations

    Science.gov (United States)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-05-01

    In the present research work, the FT-IR, FT-Raman and 13C and 1H NMR spectra of the α-Methylstyrene were recorded. The observed fundamental frequencies in finger print as well as functional group regions were assigned according to their uniqueness region. The Gaussian computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The impact of the presence of vinyl group in phenyl structure of the compound is investigated. The modified vibrational pattern of the molecule associated vinyl group was analyzed. Moreover, 13C NMR and 1H NMR were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed.

  13. High capacity lithium ion batteries composed of cobalt oxide nanoparticle anodes and Raman spectroscopic analysis of nanoparticle strain dynamics in batteries.

    Science.gov (United States)

    Islam, Mohammad A; Zuba, Mateusz; DeBiase, Vincent; Noviasky, Nicholas; Hawley, Christopher J

    2018-02-16

    Cobalt nanoparticle thin films were electrophoretically deposited on copper current collectors and were annealed into thin films of hollow Co 3 O 4 nanoparticles. These thin films were directly used as the anodes of lithium ion batteries (LIBs) without the addition of conducting carbons and bonding agents. LIBs thus fabricated show high gravimetric capacities and long cycle lives. For ≈1.0 μm thick Co 3 O 4 nanoparticle films the gravimetric capacities of the batteries were more than 800 mAh g -1 at a current rate of C/15, which is about 90% of the theoretical maximum. Additionally, the batteries were able to undergo 200 charge/discharge cycles at a relatively fast rate of C/5 and maintain 50% of the initial capacity. In order to understand the electrochemistry of lithiation in the context of nanoparticles, Raman spectra were collected at different stages of the electrode cycles to determine the chemical and structural changes in the nanomaterials. Our results indicate that initially the electrode nanoparticles were under significant strain and as the battery underwent many cycles of charging/discharging the nanoparticles experienced progressive strain relaxation.

  14. Infrared and Raman spectroscopic studies of tris-[3-(trimethoxysilyl)propyl] isocyanurate, its sol-gel process, and coating on aluminum and copper.

    Science.gov (United States)

    Li, Ying-Sing; Church, Jeffrey S; Woodhead, Andrea L; Vecchio, Nicolas E; Yang, Johnny

    2014-11-11

    Tris-[3-(trimethoxysilyl)propyl] isocyanurate (TTPI) has been used as a precursor to prepare a sol using ethanol as the solvent under acidic conditions. The sol-gel was applied for the surface treatment of aluminum and copper. Infrared and Raman spectra have been recorded for pure TTPI and the TTPI sol, xerogel and TTPI sol-gel coated metals. From the vibrational spectra, TTPI is likely to have the C1 point group. Vibrational assignments are suggested based on group frequencies, the expected reactions in the sol-gel process and the vibrational studies of some related molecules. From the experimental infrared spectra of xerogels annealed at different temperatures and from the thermal-gravimetric analysis, it is found that the TTPI xerogel decomposes at around 450°C with silica being the major decomposition product. A cyclic voltammetric study of the metal electrodes coated with different concentrations of TTPI ranging from 5% to 42% (v/v) has shown that the films with high concentrations of sol would provide better corrosion protection for aluminum and copper. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Determination of diffusion coefficients of carbon dioxide in water between 268 and 473 K in a high-pressure capillary optical cell with in situ Raman spectroscopic measurements

    Science.gov (United States)

    Lu, Wanjun; Guo, Huirong; Chou, I.-Ming; Burruss, R.C.; Li, Lanlan

    2013-01-01

    Accurate values of diffusion coefficients for carbon dioxide in water and brine at reservoir conditions are essential to our understanding of transport behavior of carbon dioxide in subsurface pore space. However, the experimental data are limited to conditions at low temperatures and pressures. In this study, diffusive transfer of carbon dioxide in water at pressures up to 45 MPa and temperatures from 268 to 473 K was observed within an optical capillary cell via time-dependent Raman spectroscopy. Diffusion coefficients were estimated by the least-squares method for the measured variations in carbon dioxide concentration in the cell at various sample positions and time. At the constant pressure of 20 MPa, the measured diffusion coefficients of carbon dioxide in water increase with increasing temperature from 268 to 473 K. The relationship between diffusion coefficient of carbon dioxide in water [D(CO2) in m2/s] and temperature (T in K) was derived with Speedy–Angell power-law approach as: D(CO2)=D0[T/Ts-1]m where D0 = 13.942 × 10−9 m2/s, Ts = 227.0 K, and m = 1.7094. At constant temperature, diffusion coefficients of carbon dioxide in water decrease with pressure increase. However, this pressure effect is rather small (within a few percent).

  16. Crystal growth of barium nitrate on thiol-terminated self-assembled monolayers and a Raman spectroscopic investigation of the crystal facets

    Science.gov (United States)

    Lu, Fei; Zhao, Bing; Li, Ran; Ruan, Weidong

    2015-09-01

    Self-assembled monolayers (SAMs) of (3-mercaptopropyl)trimethoxysilane (MPTS) were used as templates to induce the nucleation and growth of Ba(NO3)2 microcrystals. X-ray diffraction (XRD) patterns and optical microscopy images were employed to investigate the crystallinity and morphology of the microcrystals. It is interesting that the soaking direction of the templates plays an important role in the crystal growth process. When the MPTS-modified substrates were soaked in a vertical manner, square-like microcrystals with the (100) orientation were synthesized; however, when the substrates were soaked in a horizontal manner, triangular-like microcrystals with the (111) orientation were obtained. These differences may be due to the different regulatory mechanisms involved in the modulation of the crystal growth by the SAMs. These mechanistic discoveries pave a new way to control and design new crystals. Another interesting phenomenon is that the Raman intensity of the (111) facet of the triangular Ba(NO3)2 microcrystals is five times that of the (100) facet. By using this difference, the crystal facet index can be rapidly determined.

  17. Fourier transform infrared and Raman spectroscopic study of the effect of the thermal treatment and extraction methods on the characteristics of ayocote bean starches.

    Science.gov (United States)

    Bernardino-Nicanor, Aurea; Acosta-García, Gerardo; Güemes-Vera, Norma; Montañez-Soto, José Luis; de Los Ángeles Vivar-Vera, María; González-Cruz, Leopoldo

    2017-03-01

    Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm -1 in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm -1 indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm -1 , indicating the product of the retrogradation process. The thermal treatment reduced the crystallinity as well as short-range order. Raman spectroscopy revealed that acute changes occurred in the polysaccharide bonds after thermal treatment. This study showed that the thermal treatment affected the structural properties of ayocote bean starches, the interactions of the lipids and proteins with starch molecules and the retrogradation process of starch.

  18. FT-IR, FT-Raman and UV spectroscopic investigation, electronic properties, electric moments, and NBO analysis of anethole using quantum chemical calculations.

    Science.gov (United States)

    Sinha, L; Prasad, O; Chand, S; Sachan, A K; Pathak, S K; Shukla, V K; Karabacak, M; Asiri, A M

    2014-12-10

    FT-IR and FT-Raman spectra of anethole (1-Methoxy-4-(1-propenyl)benzene), a flavoring agent of commercial value, have been recorded in the regions 4000-400 and 4000-100cm(-1) respectively. The structure of the title molecule has been optimized and the structural parameters have been calculated by DFT/B3LYP method with 6-311++G(d,p) basis set. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and scaled calculated wavenumbers has been achieved. UV-Vis spectrum of the title compound was recorded in the region 200-500nm and the electronic properties such as HOMO and LUMO energies and associated energy gap were calculated by Time dependent-density functional theory (TD-DFT) approach. Nonlinear optical (NLO) study divulges the nonlinear properties of the molecule. Stability of the title molecule arising from hyper-conjugative interactions and charge delocalization has been investigated using natural bond orbital (NBO) analysis. The theoretical results were found to be in coherence with the measured experimental data. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Tackling field-portable Raman spectroscopy of real world samples

    Science.gov (United States)

    Shand, Neil C.

    2008-10-01

    A major challenge confronting first responders, customs authorities and other security-related organisations is the accurate, rapid, and safe identification of potentially hazardous chemicals outside a laboratory environment. Currently, a range of hand portable Raman equipment is commercially available that is low cost and increasingly more sophisticated. These systems are generally based on the 785nm Stokes shifted Raman technique with many using dispersive grating spectrometers. This technique offers a broad range of capabilities including the ability to analyse illicit drugs, explosives, chemical weapons and pre-cursors but still has some fundamental constraints. 'Real world' samples, such as those found at a crime scene, will often not be presented in the most accessible manner. Simple issues such as glass fluorescence can make an otherwise tractable sample impossible to analyse in-situ. A new generation of portable Raman equipment is currently being developed to address these issues. Consideration is given to the use of longer wavelength for fluorescence reduction. Alternative optical designs are being tested to compensate for the signal reduction incurred by moving to longer wavelengths. Furthermore, the use of anti-Stokes spectroscopy is being considered as well as investigating the robustness and portability of traditional Fourier Transform interferometer designs along with future advances in detector technology and ultra small spectrometers.

  20. Spectroscopic [FT-IR and FT-Raman] and theoretical [UV-Visible and NMR] analysis on α-Methylstyrene by DFT calculations.

    Science.gov (United States)

    Karthikeyan, N; Joseph Prince, J; Ramalingam, S; Periandy, S

    2015-05-15

    In the present research work, the FT-IR, FT-Raman and (13)C and (1)H NMR spectra of the α-Methylstyrene were recorded. The observed fundamental frequencies in finger print as well as functional group regions were assigned according to their uniqueness region. The Gaussian computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The impact of the presence of vinyl group in phenyl structure of the compound is investigated. The modified vibrational pattern of the molecule associated vinyl group was analyzed. Moreover, (13)C NMR and (1)H NMR were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  1. Spectroscopic (FT-IR, FT-Raman, UV, NMR, NLO) investigation, molecular docking and molecular simulation dynamics on 1-Methyl-3-Phenylpiperazine

    Science.gov (United States)

    Subashini, K.; Periandy, S.

    2017-09-01

    The title compound was analyzed, by recording FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm-1) spectra in solid phase, 1H and 13C NMR in CDCl3 (deuterated chloroform) and UV spectrum (200-400 nm) in solid phase and in ethanol solution. Conformational analysis was done using semi-empirical method PM6. The computed wavenumbers obtained from B3LYP and B3PW91 functionals along with 6-311++G (d, p) basis sets were scaled so as to agree with the experimental values and the scaling factors have been reported. All fundamental modes have been assigned based on the potential energy distribution (PED) values and the structure of the molecule was analyzed in terms of parameters like bond length, bond angle and dihedral angles through B3LYP and B3PW91 functionals along with 6-311++G(d,p) basis set. The observed HOMO-LUMO mappings reveal the different charge transfer possibilities within the molecule. The percentage contribution of a group to each molecular orbital was calculated using Gauss Sum program. Natural bond orbital analysis was computed and possible transition were correlated with the electronic transitions. Mulliken charges, electrostatic potential charges and natural charges are also predicted. The theoretical 1H and 13C NMR chemical shifts were computed using B3LYP functionals using 6-311++G (2d, p) basis sets. The temperature dependence of the thermodynamic properties; heat capacity, entropy and enthalpy for the title compound were also determined by B3LYP functional with 6-311++G (d, p) basis set. Molecular docking study shows that the title compound might exhibit inhibitory activity against Clostridium botulinum (2J3X). The interaction of the ligand (title molecule) with 2J3X for 2 ns duration and radial distribution function have been observed through molecular dynamics simulations.

  2. Infrared and Raman spectroscopic methods for characterization of Taxus baccata L.--Improved taxane isolation by accelerated quality control and process surveillance.

    Science.gov (United States)

    Gudi, Gennadi; Krähmer, Andrea; Koudous, Iraj; Strube, Jochen; Schulz, Hartwig

    2015-10-01

    Different yew species contain poisonous taxane alkaloids which serve as resources for semi-synthesis of anticancer drugs. The highly variable amounts of taxanes demand new methods for fast characterization of the raw plant material and the isolation of the target structures during phyto extraction. For that purpose, applicability of different vibrational spectroscopy methods in goods receipt of raw plant material and in process control was investigated and demonstrated in online tracking isolation and purification of the target taxane 10-deacetylbaccatin III (10-DAB) during solvent extraction. Applying near (NIRS) and mid infrared spectroscopy (IRS) the amount of botanical impurities in mixed samples of two different yew species (R(2)=0.993), the leave-to-wood ratio for Taxus baccata material (R(2)=0.94) and moisture in dried yew needles (R(2)=0.997) can be quantified. By partial least square analysis (PCA) needles of different Coniferales species were successfully discriminated by Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FT-IR). The analytical potential of ATR-FT-IR and Fourier Transform-Raman Spectroscopy (FT-RS) in process control of extraction and purification of taxanes is demonstrated for determination of the water content in methanolic yew extracts (R(2)=0.999) and for quantification of 10-DAB (R(2)=0.98) on a highly sophisticated level. The decrease of 10-DAB in the plant tissue during extraction was successfully visualized by FT-IR imaging of thin cross sections providing new perspectives for process control and design. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Effects of LED or laser phototherapy on bone defects grafted with MTA and irradiated with laser or LED light: a comparative Raman spectroscopic study

    Science.gov (United States)

    Pinheiro, Antonio L. B.; Soares, Luiz G. P.; Barbosa, Artur Felipe S.; Silveira, Landulfo, Jr.

    2012-03-01

    We studied peaks of calcium hydroxyapatite - CHA on defects grafted with MTA, treated or not with Light Emitting Diode - LED or IR Laser. 54 rats were divided in 6 groups each subdivided into 3 subgroups (15,21,30d). LED (λ850 +/- 10nm) or IR Laser (λ850 nm) was applied over (LED) or in 4 points around the defect at 48 h intervals for 15 days. Raman readings were taken at the surface of the defect. The smaller overall intensity of the peak was found in Group MTA + Laser (1510.2 +/- 274.1) and the highest on Group LED (2322 +/- 715). There were no statistically significant differences between non-irradiated subjects on regards the CHA peaks. On the other hand, there were statistically significant differences between the Group Clot and LED, Clot and Laser, and Clot and MTA + Laser (p =0.01, p = 0.02, p = 0.003). There were no significant differences between Group MTA and MTA + LED (p=0.2) but significant differences were seen between Groups MTA and MTA + Laser (p=0.01). Significant differences were also observed between Groups LED and Laser (p LED and MTA + Laser (p=0.009). MTA, due to its characteristics, seemed to be directly affected by the light. However, the use of either phototherapy positively affected bone healing similarly as observed on different studies using other biomaterials. The overall analysis of our results indicated that the use of either light source resulted in a better, more advanced, and of quality bone repair.

  4. Conformational analysis, spectroscopic study (FT-IR, FT-Raman, UV, 1H and 13C NMR), molecular orbital energy and NLO properties of 5-iodosalicylic acid.

    Science.gov (United States)

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-02-05

    In this study, 5-iodosalicylic acid (5-ISA, C7H5IO3) is structurally characterized by FT-IR, FT-Raman, NMR and UV spectroscopies. There are eight conformers, Cn, n=1-8 for this molecule therefore the molecular geometry for these eight conformers in the ground state are calculated by using the ab-initio density functional theory (DFT) B3LYP method approach with the aug-cc-pVDZ-PP basis set for iodine and the aug-cc-pVDZ basis set for the other elements. The computational results identified that the most stable conformer of 5-ISA is the C1 form. The vibrational spectra are calculated DFT method invoking the same basis sets and fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method with PQS program. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis for C1 conformer were calculated using the same method. The energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT) results complement with the experimental findings. Besides, charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, molecular electrostatic potential (MEP) are calculated and presented. The NMR chemical shifts ((1)H and (13)C) spectra are recorded and calculated using the gauge independent atomic orbital (GIAO) method. Mulliken atomic charges of the title molecule are also calculated, interpreted and compared with salicylic acid. The optimized bond lengths, bond angles and calculated NMR and UV, vibrational wavenumbers showed the best agreement with the experimental results. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. STRUCTURE FEATURES OF THE SODIUM-GERMANATE GLASSES DOPED WITH YTTERBIUM ERBIUM RETRIEVED FROM RAMAN SPECTROSCOPY

    Directory of Open Access Journals (Sweden)

    I. M. Sevastianova

    2016-09-01

    Full Text Available Subject of Research.The paper deals with study of Raman spectra and luminescence spectra in the visible region of the sodium-germanate glass: 49 GeO2 – 13 Na2O – 27 Yb2O3 – 11 La2O3 - 0,25 Er2O3 and presents research results. In addition, this glass is doped with 5 mol% of the following components MgO, BaO, Al2O3, PbO, Nb2O5, TiO2, SiO2, P2O5 in order to study the effect of these additives on the structure of the glassy matrix and the anti-Stokes luminescence spectra of erbium ions. Method. Raman scatteringspectra were recorded by Renishaw inVia Raman Microscope. Excitation source is a helium neon laser (λ= 633 nm with power equal to 50Wt. Anti-Stokes luminescence of erbium ions was registered in spectral region of 450–750 nm at room temperature (excitation laser wavelength is 975 nm, power is 1Wt. Main Results. It was shown that the structure of the initial glass does not change with the introduction of niobium as Nb2O5 in any coordination plays a role of network forming, building a single mixed grid with tetrahedrons [GeO4]. Introduction of the second glass former P2O5 leads to loosening germanate structure due to the appearance of the phosphate sublattice. This leads to a redistribution of the relative intensity of up-conversion luminescence bands with maxima at 540 and 670 nm compared with the initial glass. Introduction of additives PbO, MgO, Al2O3, TiO2 results in a multicenter structure. In case of titanium oxide addition it leads to a change in the relative intensities of the erbium luminescence.

  6. In situ optical and Raman spectroscopic observations of the effects of pressure and fluid composition on liquid-liquid phase separation in aqueous cadmium sulfate solutions (≤400 °C, 50 MPa) with geological and geochemical implications

    Science.gov (United States)

    Wan, Ye; Wang, Xiaolin; Hu, Wenxuan; Chou, I.-Ming; Wang, Xiaoyu; Chen, Ying; Xu, Zhimin

    2017-08-01

    This study presents the first description of liquid-liquid phase separation in a vapor-saturated CdSO4 solution at temperatures above 222.2 °C in fused silica capillary tubing, in which a sulfate-rich liquid (Srich) phase separates from an initially homogeneous aqueous solution and coexists with the remaining sulfate-poor liquid (Spoor) phase and a vapor phase. This phase behavior is characterized by a lower critical solution temperature (∼222.2 °C), which is a macroscale property of polymer mixtures. In situ Raman spectroscopy shows an increase in Cd2+-SO42- associations with increasing temperature, especially in the immiscible Srich phase. Phase behavior observations and in situ Raman spectroscopic analyses confirm our previous conclusion that strong ion associations are responsible for the liquid-liquid phase separation in inorganic solutions. The effects of pressure and the fluid composition on liquid-liquid phase separation are also investigated. The temperature of liquid-liquid phase separation increases almost linearly with pressure at a rate of ∼0.5 °C/MPa and decreases with the addition of methanol. Both decreases in pressure and increases in the methanol concentration decrease the dielectric constant of the solutions, favoring the Cd2+-SO42- interaction and thus liquid-liquid phase separation. The capillary size also exerts a strong influence on liquid-liquid phase separation because the immiscible Srich phase is more stable in fused silica capillary tubing with an inner diameter of ≤300 μm. Therefore, liquid-liquid phase separation can occur in hydrothermal fluids hosted in porous rocks/sediments, especially those that are rich in low-dielectric-constant components and/or at low pressures. Liquid-liquid phase separation may play an important role in the formation of Mississippi-valley-type ore deposits because the ore-forming fluids are enriched in low-dielectric-constant components. The occurrence of liquid-liquid phase separation can promote

  7. Raman spectroscopy

    Science.gov (United States)

    Raman spectroscopy has gained increased use and importance in recent years for accurate and precise detection of physical and chemical properties of food materials, due to the greater specificity and sensitivity of Raman techniques over other analytical techniques. This book chapter presents Raman s...

  8. Interfacing capillary electrophoresis and surface-enhanced resonance Raman spectroscopy for the determination of dye compounds

    NARCIS (Netherlands)

    Arraez Roman, D.; Efremov, E.V.; Ariese, F.; Segura Carretero, A.; Gooijer, C.

    2005-01-01

    The at-line coupling of capillary electrophoresis (CE) and surface-enhanced resonance Raman spectroscopy (SERRS) was optimized for the separation and subsequent spectroscopic identification of charged analytes (dye compounds). Raman spectra were recorded following deposition of the electropherogram

  9. Universality of Coherent Raman Gain Suppression in Gas-Filled Broadband-Guiding Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Mridha, M. K.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-03-01

    As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via a pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via a pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves—synchronized vibrations of a large population of molecules—have identical propagation constants for both processes; i.e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero-dispersion wavelength provides an ideal system for observing this effect. Here we report that Raman gain suppression is actually a universal feature of SRS in gas-filled hollow-core fibers and that it can strongly impair SRS even when the phase mismatch is high, particularly at high pump powers when it is normally assumed that nonlinear processes become more (not less) efficient. This counterintuitive result means that intermodal stimulated Raman scattering (for example, between LP01 and LP11 core modes) begins to dominate at high power levels. The results reported have important implications for fiber-based Raman shifters, amplifiers, or frequency combs, especially for operation in the ultraviolet, where the Raman gain is much higher.

  10. Raman spectroscopy of white wines.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Raman scattering study of the anharmonic effects in CeO2-y nanocrystals

    Science.gov (United States)

    Popović, Z. V.; Dohčević-Mitrović, Z.; Cros, A.; Cantarero, A.

    2007-12-01

    We have studied the temperature dependence of the F2g Raman mode phonon frequency and broadening in CeO2-y nanocrystals. The phonon softening and phonon linewidth are calculated using a model which takes into account the three-and four-phonon anharmonic processes. A detailed comparison of the experimental data with theoretical calculations revealed the predominance of four-phonon anharmonic processes in the temperature dependence of the phonon energy and broadening of the nanocrystals. On the other hand, three-phonon processes dominate the temperature behavior of phonons in polycrystalline samples. The anti-Stokes/Stokes peak intensity ratio was also investigated and found to be smaller for nanosized CeO2 powders than in the bulk counterpart.

  12. Raman scattering study of the anharmonic effects in CeO2-y nanocrystals

    International Nuclear Information System (INIS)

    Popovic, Z V; Dohcevic-Mitrovic, Z; Cros, A; Cantarero, A

    2007-01-01

    We have studied the temperature dependence of the F 2g Raman mode phonon frequency and broadening in CeO 2-y nanocrystals. The phonon softening and phonon linewidth are calculated using a model which takes into account the three-and four-phonon anharmonic processes. A detailed comparison of the experimental data with theoretical calculations revealed the predominance of four-phonon anharmonic processes in the temperature dependence of the phonon energy and broadening of the nanocrystals. On the other hand, three-phonon processes dominate the temperature behavior of phonons in polycrystalline samples. The anti-Stokes/Stokes peak intensity ratio was also investigated and found to be smaller for nanosized CeO 2 powders than in the bulk counterpart

  13. Raman scattering study of the anharmonic effects in CeO{sub 2-y} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Z V [Center for Solid State Physics and New Materials, Institute of Physics, Pregrevica 118, 11080 Belgrade (Serbia); Dohcevic-Mitrovic, Z [Center for Solid State Physics and New Materials, Institute of Physics, Pregrevica 118, 11080 Belgrade (Serbia); Cros, A [Materials Science Institute, University of Valencia, P O Box 22085, E-46071, Valencia (Spain); Cantarero, A [Materials Science Institute, University of Valencia, P O Box 22085, E-46071, Valencia (Spain)

    2007-12-12

    We have studied the temperature dependence of the F{sub 2g} Raman mode phonon frequency and broadening in CeO{sub 2-y} nanocrystals. The phonon softening and phonon linewidth are calculated using a model which takes into account the three-and four-phonon anharmonic processes. A detailed comparison of the experimental data with theoretical calculations revealed the predominance of four-phonon anharmonic processes in the temperature dependence of the phonon energy and broadening of the nanocrystals. On the other hand, three-phonon processes dominate the temperature behavior of phonons in polycrystalline samples. The anti-Stokes/Stokes peak intensity ratio was also investigated and found to be smaller for nanosized CeO{sub 2} powders than in the bulk counterpart.

  14. Multiple Raman up-conversion of radiation from pre-existing Langmuir turbulence

    Science.gov (United States)

    Russell, D.; Goldman, M.; Newman, D.

    1985-07-01

    Little is known regarding the mechanisms involved in the production of radiation at frequencies which are much higher than the maximum plasma frequency in nonmagnetic plasmas. It is pointed out that radiation at high multiples of the plasma frequency has been observed in laser-pellet experiments, in relativistic beam-plasma interactions, and in low-energy beam-plasma interactions. Radiation at twice the plasma frequency can be produced by coalescence of two Langmuir waves. Another approach is based on radiation near the plasma frequency or its second harmonic, produced by instability or by external sources. Raman scatter from preexisting Langmuir turbulence is permitted repeatedly. At each step such scattering will produce frequency upshifts (anti-Stokes process) and downshifts (Stokes process). The present paper is concerned with this process. Attention is given to equilibrium spectra, analytic approximations, laser-plasma interaction and coherent radiation from relativistic electron beams.

  15. Impact of firing temperature on multi-wavelength selective Stokes and anti-Stokes luminescent behavior by Gd2O2S:Er,Yb phosphor and its application in solar energy harvesting

    Science.gov (United States)

    Kataria, V.; Mehta, D. S.

    2018-04-01

    Erbium (Er3+)-ytterbium (Yb3+) doped gadolinium oxysulphide (Gd2O2S) phosphor has been developed via a facile method of solid-state flux fusion, and offers two-fold spectrum modification with highly intense Stokes and anti-Stokes shift. The effect of the firing cycle on the photoluminescent response and morphology of Gd2O2S:Er,Yb is scrutinized, wherein the firing temperature was varied (1000 °C-1250 °C), keeping firing time and all other parameters constant. Interestingly, the nanostructures fired below 1150 °C showed nanorods of diameter ~200 nm and length ~1-2 µm, whereas firing at 1150 °C and above rendered nanospheres with small diameter, ~350 nm. Highly bright upconversion (UC) emission was achieved even under an extremely low excitation power density of 800 µW cm-2 from a 980 nm laser, and was comfortably visible to the naked eye. The incident power dependent studies disclosed increase in UC-emission intensity with increasing excitation power and a quasi-linear dependence on excitation power density. Intense characteristic UC-emission of Er3+ excited states at 525 nm, 556 nm and 668 nm were observed, and the green emission band was found to be dominant over the red band in intensity. Concurrently, downconversion (DC) emission at 556 nm and 669 nm was also exhibited under ultraviolet excitation (285 nm and 380 nm), with the red band being more powerful than the green, unlike UC-emission. Firing temperature dependent studies divulged the dependence of luminescence intensity on the firing cycle of the luminophore and formation of the respective luminescent phase. The UC-emission intensity was found to be maximum for samples fired at 1150 °C, whereas samples fired at 1000 °C showed the highest DC-emission intensity. The excitation and emission profile of single Gd2O2S:Er,Yb phosphor lying in the desired spectral region and as a dual spectral converter marks its possible application for enhanced harvesting of sunlight.

  16. Surface-Enhanced Raman Scattering Physics and Applications

    CERN Document Server

    Kneipp, Katrin; Kneipp, Harald

    2006-01-01

    Almost 30 years after the first reports on surface-enhanced Raman signals, the phenomenon of surface-enhanced Raman scattering (SERS) is now well established. Yet, explaining the enhancement of a spectroscopic signal by fouteen orders of magnitude continues to attract the attention of physicists and chemists alike. And, at the same time and rapidly growing, SERS is becoming a very useful spectroscopic tool with exciting applications in many fields. SERS gained particular interest after single-molecule Raman spectroscopy had been demonstrated. This bookl summarizes and discusses present theoretical approaches that explain the phenomenon of SERS and reports on new and exciting experiments and applications of the fascinating spectroscopic effect.

  17. Raman facility

    Data.gov (United States)

    Federal Laboratory Consortium — Raman scattering is a powerful light scattering technique used to diagnose the internal structure of molecules and crystals. In a light scattering experiment, light...

  18. Raman Scattering Temperature Probe of Laser Disk Marking.

    Science.gov (United States)

    Chan, Pui Kwong

    Laser Raman backscattering has been used to measure the marking temperature on optical disks due to laser-induced heating. Continuous tracks are written on organic films using a 70mW CW HeNe laser. The laser beam that writes is used to collect the Raman scattering data. The beam is processed through a double spectrometer and a standard photon counting system, and the ratio of the anti-Stokes to the Stokes Raman line intensities provides a measure of the temperature of the region being marked. A table of computer simulated, laser-induced temperature distribution and its corresponding Raman intensity ratio as a function of laser power is first prepared. The actual laser induced temperature developed on the films is obtained by matching the measured ratio and the calculated one. Experiments have been done at laser powers below and up to the point for threshold of marking. It is concluded that marking occurs at about 20^circC above the softening point (221^circC) of the organic films. However, these have not reached their decomposition point (>350^circ C). The temperature rise on the films is found to be linearly proportional to the incident laser power. For weakly absorptive films and long marking period, computer simulations show that the thicker the films the more effective in raising the surface temperature. However, for the dye/polymer films studied, a thickness of 0.45 μm gives the optimal heating efficiency. Similar simulations for a realistic marking process (for highly absorptive films) using laser diode pulses of 100 ns show that the heating efficiency is governed by the thin film anti-reflection effect and is optimal at a thickness of 0.12 mum.

  19. Raman Spectroscopy.

    Science.gov (United States)

    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…

  20. Raman active components of skin cancer

    OpenAIRE

    Feng, Xu; Moy, Austin J; Nguyen, Hieu T. M.; Zhang, Jason; Fox, Matthew C.; Sebastian, Katherine R.; Reichenberg, Jason S.; Markey, Mia K.; Tunnell, James W.

    2017-01-01

    Raman spectroscopy (RS) has shown great potential in noninvasive cancer screening. Statistically based algorithms, such as principal component analysis, are commonly employed to provide tissue classification; however, they are difficult to relate to the chemical and morphological basis of the spectroscopic features and underlying disease. As a result, we propose the first Raman biophysical model applied to in vivo skin cancer screening data. We expand upon previous models by utilizing in situ...

  1. Spectroscopic studies (FTIR, FT-Raman and UV), potential energy surface scan, normal coordinate analysis and NBO analysis of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl) piperidine-3,4,5-triol by DFT methods.

    Science.gov (United States)

    Isac Paulraj, E; Muthu, S

    2013-05-01

    This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR spectrum (4000-400 cm(-1)) and FT-Raman spectrum (4000-100 cm(-1)) in solid phase was recorded for HEHMPT. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water was recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule were obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Crystallization and spectroscopic studies of manganese malonate

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The preparation of manganese malonate crystals by gel method and its spectroscopic studies are reported. X-ray diffraction (XRD) pattern reveals the crystalline nature. The FTIR and FT Raman spectra of the crystals are recorded and the vibrational assignments are given with possible explanations. Diffuse reflec-.

  3. Raman spectroscopy of bone metastasis

    Science.gov (United States)

    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.

  4. Raman Chandrasekar

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Raman Chandrasekar. Articles written in Resonance – Journal of Science Education. Volume 13 Issue 5 May 2008 pp 430-439 General Article. How Children Learn to Use Language - An Overview of R. Narasimhan's Ideas on Child Language Acquisition.

  5. CV Raman

    Indian Academy of Sciences (India)

    style, philosophy and motivations. We thus have here an authoritative biography of the most .... What motivated Raman to do the extraordinary things he did against all odds? What was the secret of his success? ... to Professor S. Chandrasekhar for permission to quote some of his statements. I am very indebted to Prof.

  6. Molecular structure, spectroscopic (FTIR, FT-Raman, 13C and 1H NMR, UV), polarizability and first-order hyperpolarizability, HOMO-LUMO analysis of 2,4-difluoroacetophenone.

    Science.gov (United States)

    Jeyavijayan, S

    2015-02-05

    The FTIR and FT-Raman spectra of 2,4-difluoroacetophenone (DFAP) have been recorded in the regions 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. The optimum molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities, were calculated by density functional theory (DFT/B3LYP) method with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of DFAP is also reported based on total energy distribution (TED). Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The MEP map shows the negative potential sites are on oxygen atom as well as the positive potential sites are around the hydrogen atoms. The UV-Vis spectral analysis of DFAP has also been done which confirms the charge transfer of DFAP. The chemical shifts of H atoms and C atoms were calculated using NMR analysis. Furthermore, the polarizability, the first hyperpolarizability and total dipole moment of the molecule have been calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. On the emergence of Raman signals characterizing multicenter nanoscale interactions

    Science.gov (United States)

    Williams, Mathew D.; Bradshaw, David S.; Andrews, David L.

    2016-04-01

    Raman scattering is most commonly associated with a change in vibrational state within one molecule, with signals in the corresponding spectrum widely used to identify material structures. When the corresponding theory is developed using quantum electrodynamics, the fundamental scattering process is described by a single photon of one radiation mode being annihilated with the concurrent creation of another photon; the two photon energies differ by an amount corresponding to the transfer of vibrational energy within the system. Here, we consider nanoscale interactions between neighboring molecules to mediate the process, by way of a virtual photon exchange to connect the evolution of the two molecular states. We consider both a single and pair of virtual photon exchanges. Our analysis deploys two realistic assumptions: in each pairwise interaction the two components are considered to be (i) chemically different and (ii) held in a fixed orientation with respect to each other, displaced by an amount equivalent to the near-field region; resulting in higher order dependences on displacement R becoming increasingly significant, and at the limit the short-range R-6 term can even dominate over R-3 dependence. In our investigation one center undergoes a change in vibrational energy; each neighboring molecule returns to the electronic and vibrational state in which it began. For the purposes of providing results, a Stokes transition has been assumed; analogous principles hold for the anti-Stokes counterpart. Experimentally, there is no change to the dependence on the intensity of laser light. However, the various mechanisms presented herein lead to different selection rules applying in each instance. In some cases specifically identifiable mechanisms will be active for a given transition, leading to new and characteristic lines in the Raman spectrum. A thorough investigation of all physically achievable mechanisms will be detailed in this work.

  8. Photodynamics and physics behind tunable solid-state lasers

    Science.gov (United States)

    Alfano, R. R.; Petricevic, V.; Demos, S. G.

    1991-02-01

    Research was focused in two areas. The use of excite-and-probe anti-Stokes Raman scattering apparatus, the nonequilibrium phonons which participate in the overall complex nonradiative decay in tunable solid state laser crystals, were directly identified. Rise and decay behavior of different Raman-active phonon modes were measured. A new laser ion, Chromium 4(+) in chromium-doped forsterite was discovered, and its spectroscopic and laser characteristics were investigated.

  9. Raman Spectroscopic Study of Tungsten(VI) Oxosulfato Complexes in WO3–K2S2O7–K2SO4 Molten Mixtures: Stoichiometry, Vibrational Properties and Molecular Structure

    DEFF Research Database (Denmark)

    Paulson, Andreas L.; Kalampounias, Angelos G.; Berg, Rolf W.

    2011-01-01

    The dissolution reaction of WO3 in pure molten K2S2O7 and in molten K2S2O7-K2SO4 mixtures is studied under static equilibrium conditions in the XWO3 0 = 0-0.33 mol fraction range at temperatures up to 860 C. High temperature Raman spectroscopy shows that the dissolution leads to formation of WVI...

  10. The spectroscopic (FT-IR, FT-Raman, (l3)C, (1)H NMR and UV) and NBO analyses of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid.

    Science.gov (United States)

    Vitnik, Vesna D; Vitnik, Željko J

    2015-03-05

    In this work, we will report a combined experimental and theoretical study on molecular and vibrational structure of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid (BEPA). BEPA has been characterized by FT-IR, FT-Raman, (1)H NMR, (13)C NMR and UV spectroscopy. The FT-IR and FT-Raman spectra of BEPA were recorded in the solid phase. The optimized geometry was calculated by B3LYP and M06-2X methods using 6-311G(d,p) basis set. The FT-IR and FT-Raman spectra of BEPA were calculated at the same level and were interpreted in terms of Potential Energy Distribution (PED) analysis. The scaled theoretical wavenumber showed very good agreement with the experimental values. The (1)H and (l3)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge-Independent Atomic Orbital (GIAO) method. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. Density plots over the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) energy surface directly identifies the donor and acceptor atoms in the molecule. It also provides information about the charge transfer within the molecule. To obtain chemical reactivity of the molecule, the molecular electrostatic potential (MEP) surface map is plotted over the optimized geometry of the molecule. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Spectroscopic (FT-IR, FT-Raman, UV absorption, 1H and 13C NMR) and theoretical (in B3LYP/6-311++G** level) studies on alkali metal salts of caffeic acid.

    Science.gov (United States)

    Świsłocka, Renata

    2013-01-01

    The effect of some metals on the electronic system of benzoic and nicotinic acids has recently been investigated by IR, Raman and UV spectroscopy [1-3]. Benzoic and nicotinic acids are regarded model systems representing a wide group of aromatic ligands which are incorporated into enzymes. In this work the FT-IR (in solid state and in solution), FT-Raman, UV absorption and (1)H and (13)C NMR spectra of caffeic acid (3,4-dihydroxycinnamic acid) and its salts with lithium, sodium, potassium, rubidium and caesium were registered, assigned and analyzed. The effect of alkali metals on the electronic system of ligands was discussed. Studies of differences in the number and position of bands from the IR, Raman, UV absorption spectra and chemical shifts from NMR spectra allowed to conclude on the distribution of electronic charge in the molecules, the delocalization energy of π electrons and the reactivity of ligands in metal complexes. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G** basis set. Bond lengths, angles and dipole moments for the optimized structures of caffeic acid and lithium, sodium, potassium caffeinates were also calculated. The theoretical wavenumbers and intensities of IR spectra were obtained. The calculated parameters were compared to the experimental characteristics of investigated compounds. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Quantum mechanical, spectroscopic study (FT-IR and FT - Raman), NBO analysis, HOMO-LUMO, first order hyperpolarizability and docking studies of a non-steroidal anti-inflammatory compound

    Science.gov (United States)

    Sakthivel, S.; Alagesan, T.; Muthu, S.; Abraham, Christina Susan; Geetha, E.

    2018-03-01

    Experimental and theoretical studies on the optimized geometrical structure, electronic and vibrational characteristics of (+)-(S)-2-(6-methoxynaphthalen-2-yl) propanoic acid are presented employing B3LYP/6-311++G (d,p) basis set. Simulated FT-IR and FT-Raman spectra were in concurrence with the observed spectra attained in a spectral range of FT-IR (4000 - 400 cm-1) and FT-Raman (4000 - 100 cm-1). Quantum chemical calculations and the comprehensive vibrational assignments of wavenumbers of the optimized geometry using Potential Energy Distribution (PED) were calculated with scaled quantum mechanics. The infrared intensities and Raman intensities of (+)-(S)-2-(6-methoxynaphthalen-2-yl) propanoic acid were reported. Frontier molecular orbital analysis and reactivity parameters were calculated. Molecular Electrostatic Potential (MEP), Natural Bond Orbital (NBO) analysis, Non Linear Optical (NLO) behavior and thermodynamic properties were studied. In addition, the Mulliken charge distribution and Fukui function were analyzed. Molecular docking was used to dock in the title molecule into the active site of the protein 5L9B which belongs to the class of proteins exhibiting the property as a HIF1A (Hypoxia-inducible factor 1-alpha) expression inhibitor and the minimum binding energy was detected to be -6.2 kcal/mol.

  13. Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation, conformational stability, NLO properties, HOMO-LUMO and NBO analysis of hydroxyquinoline derivatives by density functional theory calculations.

    Science.gov (United States)

    Prabavathi, N; Nilufer, A; Krishnakumar, V

    2013-10-01

    The FTIR and FT-Raman spectra of 2-hydroxyquinoline and its derivatives have been recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The optimized geometry, frequency and intensity of the vibrational bands of these compounds were obtained by the density functional theory using 6-311++G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. A detailed interpretation of the infrared and Raman spectra were also reported based on total energy distribution (TED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically simulated spectra. (1)H and (13)C NMR spectra were recorded and its corresponding nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. UV-visible spectrum of the compound was recorded and the electronic properties HOMO and LUMO energies were measured by time-dependent (TD-DFT) approach. Molecular stability and bond strength were investigated by applying the natural bond orbital analysis (NBO). The calculated HOMO and LUMO energies show that charge transfer occurs in the molecules. In addition, the non-linear optical properties were discussed from the dipole moment values and excitation wavelength in the UV-visible region. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Vibrational Spectroscopic Techniques for Probing Bioelectrochemical Systems.

    Science.gov (United States)

    Ash, Philip A; Vincent, Kylie A

    A more complete understanding of bioelectrochemical interfaces is of increasing importance in both fundamental studies and biotechnological applications of proteins. Bioelectrochemical methods provide detailed information about the activity or rate of a process, but in situ spectroscopic methods are needed to gain direct structural insight into functionally relevant states. A number of methods have been reported that allow electrochemical and spectroscopic data to be collected from the same electrode, providing direct spectroscopic 'snapshots' of protein function, and here we focus on the application of infrared and Raman spectroscopies to the study of electrode-immobilised species. The ability to probe coordination at metal centres, protonation changes in amino acid side chains, reaction-induced changes in organic cofactors or substrates, protein orientation and subtle changes in protein secondary structure simultaneously, rapidly and at room temperature means that vibrational spectroscopic approaches are almost uniquely applicable to answering a wide range of questions in bioelectrochemistry.

  15. Raman active components of skin cancer.

    Science.gov (United States)

    Feng, Xu; Moy, Austin J; Nguyen, Hieu T M; Zhang, Jason; Fox, Matthew C; Sebastian, Katherine R; Reichenberg, Jason S; Markey, Mia K; Tunnell, James W

    2017-06-01

    Raman spectroscopy (RS) has shown great potential in noninvasive cancer screening. Statistically based algorithms, such as principal component analysis, are commonly employed to provide tissue classification; however, they are difficult to relate to the chemical and morphological basis of the spectroscopic features and underlying disease. As a result, we propose the first Raman biophysical model applied to in vivo skin cancer screening data. We expand upon previous models by utilizing in situ skin constituents as the building blocks, and validate the model using previous clinical screening data collected from a Raman optical fiber probe. We built an 830nm confocal Raman microscope integrated with a confocal laser-scanning microscope. Raman imaging was performed on skin sections spanning various disease states, and multivariate curve resolution (MCR) analysis was used to resolve the Raman spectra of individual in situ skin constituents. The basis spectra of the most relevant skin constituents were combined linearly to fit in vivo human skin spectra. Our results suggest collagen, elastin, keratin, cell nucleus, triolein, ceramide, melanin and water are the most important model components. We make available for download (see supplemental information) a database of Raman spectra for these eight components for others to use as a reference. Our model reveals the biochemical and structural makeup of normal, nonmelanoma and melanoma skin cancers, and precancers and paves the way for future development of this approach to noninvasive skin cancer diagnosis.

  16. Ex vivo and in vivo coherent Raman imaging of the peripheral and central nervous system

    Science.gov (United States)

    Huff, Terry Brandon

    A hallmark of nervous system disorders is damage or degradation of the myelin sheath. Unraveling the mechanisms underlying myelin degeneration and repair represent one of the great challenges in medicine. This thesis work details the development and utilization of advanced optical imaging methods to gain insight into the structure and function of myelin in both healthy and diseased states in the in vivo environment. This first part of this thesis discusses ex vivo studies of the effects of high-frequency stimulation of spinal tissues on the structure of the node of Ranvier as investigated by coherent anti-Stokes Raman scattering (CARS) imaging (manuscript submitted to Journal of Neurosciece). Reversible paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation, beginning minutes after the onset and continuing for up to 10 min after stimulation was ceased. A mechanistic study revealed a Ca2+ dependent pathway: high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down. Also, the construction of dual-scanning CARS microscope for large area mapping of CNS tissues is detailed (Optics Express, 2008, 16:19396-193409). A confocal scanning head equipped with a rotating polygon mirror provides high speed, high resolution imaging and is coupled with a motorized sample stage to generate high-resolution large-area images of mouse brain coronal section and guinea pig spinal cord cross section. The polygon mirror decreases the mosaic acquisition time significantly without reducing the resolution of individual images. The ex vivo studies are then extended to in vivo imaging of mouse sciatic nerve tissue by CARS and second harmonic generation (SHG) imaging (Journal of Microscopy, 2007, 225: 175-182). Following a minimally invasive surgery to open the skin, CARS imaging of myelinated axons and SHG imaging of the

  17. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    Science.gov (United States)

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Fast and highly sensitive fiber-enhanced Raman spectroscopic monitoring of molecular H2 and CH4 for point-of-care diagnosis of malabsorption disorders in exhaled human breath.

    Science.gov (United States)

    Hanf, Stefan; Bögözi, Timea; Keiner, Robert; Frosch, Torsten; Popp, Jürgen

    2015-01-20

    Breath gas analysis is a novel powerful technique for noninvasive, early-stage diagnosis of metabolic disorders or diseases. Molecular hydrogen and methane are biomarkers for colonic fermentation, because of malabsorption of oligosaccharides (e.g., lactose or fructose) and for small intestinal bacterial overgrowth. Recently, the presence of these gases in exhaled breath was also correlated with obesity. Here, we report on the highly selective and sensitive detection of molecular hydrogen and methane within a complex gas mixture (consisting of H2, CH4, N2, O2, and CO2) by means of fiber-enhanced Raman spectroscopy (FERS). An elaborate FERS setup with a microstructured hollow core photonic crystal fiber (HCPCF) provided a highly improved analytical sensitivity. The simultaneous monitoring of H2 with all other gases was achieved by a combination of rotational (H2) and vibrational (other gases) Raman spectroscopy within the limited spectral transmission range of the HCPCF. The HCPCF was combined with an adjustable image-plane aperture pinhole, in order to separate the H2 rotational Raman bands from the silica background signal and improve the sensitivity down to a limit of detection (LOD) of 4.7 ppm (for only 26 fmol H2). The ability to monitor the levels of H2 and CH4 in a positive hydrogen breath test (HBT) was demonstrated. The FERS sensor possesses a high dynamic range (∼5 orders of magnitude) with a fast response time of few seconds and provides great potential for miniaturization. We foresee that this technique will pave the way for fast, noninvasive, and painless point-of-care diagnosis of metabolic diseases in exhaled human breath.

  19. Nanophotonics with Surface Enhanced Coherent Raman Microscopy

    Science.gov (United States)

    Fast, Alexander

    Nonlinear nanophotonics is a rapidly developing field of research that aims at detecting and disentangling weak congested optical signatures on the nanoscale. Sub-wavelength field confinement of the local electromagnetic fields and the resulting field enhancement is achieved by utilizing plasmonic near-field antennas. This allows for probing nanoscopic volumes, a property unattainable by conventional far-field microscopy techniques. Combination of plasmonics and nonlinear optical microscopy provides a path to visualizing a small chemical and spatial subset of target molecules within an ensemble. This is achieved while maintaining rapid signal acquisition, which is necessary for capturing biological processes in living systems. Herein, a novel technique, wide-field surface enhanced coherent anti-Stokes Raman scattering (wfSE-CARS) is presented. This technique allows for isolating weak vibrational signals in nanoscopic proximity to the surface by using chemical sensitivity of coherent Raman microspectroscopy (CRM) and field confinement from surface plasmons supported on a thin gold film. Uniform field enhancement over a large field of view, achieved with surface plasmon polaritons (SPP) in wfSE-CARSS, allows for biomolecular imaging demonstrated on extended structures like phospholipid droplets and live cells. Surface selectivity and chemical contrast are achieved at 70 fJ/mum2 incident energy densities, which is over five orders of magnitude lower than used in conventional point scanning CRM. Next, a novel surface sensing imaging technique, local field induced metal emission (LFIME), is introduced. Presence of a sample material at the surface influences the local fields of a thin flat gold film, such that nonlinear fluorescence signal of the metal can be detected in the far-field. Nanoscale nonmetallic, nonfluorescent objects can be imaged with high signal-to-background ratio and diffraction limited lateral resolution using LFIME. Additionally, structure of the

  20. Spectroscopic (FT-IR, FT-Raman, NMR and UV-Visible) and quantum chemical studies of molecular geometry, Frontier molecular orbital, NLO, NBO and thermodynamic properties of salicylic acid.

    Science.gov (United States)

    Suresh, S; Gunasekaran, S; Srinivasan, S

    2014-11-11

    The solid phase FT-IR and FT-Raman spectra of 2-hydroxybenzoic acid (salicylic acid) have been recorded in the region 4000-400 and 4000-100 cm(-1) respectively. The optimized molecular geometry and fundamental vibrational frequencies are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) method and a comparative study between Hartree Fork (HF) method at 6-311++G(d,p) level basis set. The calculated harmonic vibrational frequencies are scaled and they are compared with experimentally obtained FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The time dependent DFT method is employed to predict its absorption energy and oscillator strength. The linear polarizability (α) and the first order hyper polarizability (β) values of the investigated molecule have been computed. The electronic properties, such as HOMO and LUMO energies, molecular electrostatic potential (MEP) are also performed. Stability of the molecule arising from hyper conjugative interaction, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Published by Elsevier B.V.

  1. Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane

    Science.gov (United States)

    Arjunan, V.; Anitha, R.; Devi, L.; Mohan, S.; Yang, Haifeng

    2015-01-01

    Aromatic epoxides are causative factors for mutagenic and carcinogenic activity of polycyclic arenes. The 1,2- or 2,3-epoxy compounds are widely used to a considerable extent in the textile, plastics, pharmaceutical, cosmetics, detergent and photochemical industries. The FTIR and FT-Raman spectra of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane are recorded in the regions 4000-400 cm-1 and 4000-100 cm-1, respectively. The observed fundamentals are assigned to different normal modes of vibration. The structure of the compound has been optimised with B3LYP method using 6-311++G** and cc-pVTZ basis sets. The IR and Raman intensities are determined. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron + nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of the compounds has been performed to indicate the presence of intramolecular charge transfer. The 1H and 13C NMR chemical shifts of the molecules have been analysed.

  2. Molecular structure, spectroscopic (FT-IR, FT-Raman, NMR, UV) studies and first-order molecular hyperpolarizabilities of 1,2-bis(3-methoxy-4-hydroxybenzylidene)hydrazine by density functional method

    Science.gov (United States)

    Subramanian, N.; Sundaraganesan, N.; Jayabharathi, J.

    2010-07-01

    Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 1,2-bis(3-methoxy-4-hydroxybenzylidene)hydrazine [vanillin azine (VA)] were carried out by using density functional (DFT/B3LYP) method with 6-31G(d) as basis set. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The vibrational spectral data obtained from solid phase FT-IR and FT-Raman spectra are assigned based on the results of the theoretical calculations. The observed spectra are found to be in good agreement with calculated values. The electric dipole moment ( μ) and the first hyperpolarizability ( β) values of the investigated molecule have been computed using ab initio quantum mechanical calculations. The calculation results also show that the VA molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. A detailed interpretation of the infrared and Raman spectra of VA was also reported. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The theoretical NMR chemical shifts complement with experimentally measured ones.

  3. The effect of the association of near infrared laser therapy, bone morphogenetic proteins, and guided bone regeneration on tibial fractures treated with internal rigid fixation: a Raman spectroscopic study.

    Science.gov (United States)

    Lopes, Cibele B; Pacheco, Marcos T T; Silveira, Landulfo; Cangussú, Maria Cristina T; Pinheiro, Antonio L B

    2010-09-15

    Fractures have different etiology and treatment and may be associated or not to bone losses. Laser light has been shown to improve bone healing. We aimed to assess, through Raman spectroscopy, the level of CHA (approximately 958 cm(-1)) on complete fractures animals treated with IRF treated or not with Low Level Laser Therapy-LLLT and associated or not to BMPs and GBR. Complete tibial fractures were created on 15 animals that were divided into five groups. LLLT (Laser Unit, Kondortech, São Carlos, SP, Brazil, lambda790 nm, 4 J/cm(2)/point, 40 mW, phi approximately 0.5 cm(2), 16 J/cm(2) session) started immediately after surgery and repeated at 48 h interval (2 weeks). Animal death occurred after 30 days. Raman spectroscopy was performed at the surface of the fracture. Our results showed significant differences between the groups IRF + BL /IRF_NBL (p = 0.05); between all experimental groups and untreated bone; bone/IRF + BL; IRF + BL + Bio + GBR; IRF + BL + LLLT; IRF + BL + Bio + GBR + LLLT; IRF_NBL (p bone healing on fractured bones due to increased levels of CHA. (c) 2010 Wiley Periodicals, Inc.

  4. Synthesis, spectroscopic (FT-IR, FT-Raman, 13C, 1H, UV) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone.

    Science.gov (United States)

    Sheela, N R; Sampathkrishnan, S; Thirumalai Kumar, M; Muthu, S

    2013-05-15

    The title compound, 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone (2HPN4MPN) was synthesized and characterized by FT-IR, FT-Raman, UV-Vis and (1)HNMR, (13)CNMR spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at three parameter hybrid functional Lee-Yang-Parr/6-311++G(d,p) levels of theory. The most stable conformer of 2HPN4MPN is identified from the computational results. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The UV-Vis spectrum was recorded in chloroform solution. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements the experimental findings. The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. In addition, DFT calculations of the compound, Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and non-linear optical (NLO) properties are performed at B3LYP/6-311++G(d,p) level of theory. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Surface-enhanced Raman scattering: a new optical probe in molecular biophysics and biomedicine

    DEFF Research Database (Denmark)

    Kneipp, J.; Wittig, B.; Bohr, Henrik

    2010-01-01

    Sensitive and detailed molecular structural information plays an increasing role in molecular biophysics and molecular medicine. Therefore, vibrational spectroscopic techniques, such as Raman scattering, which provide high structural information content are of growing interest in biophysical...

  6. FT-IR, Raman and DFT studies on the vibrational spectra of 2,2-bis ...

    African Journals Online (AJOL)

    propane (baep) were examined both experimentally and theoretically including FT-IR and Raman spectroscopic methods. Among the possible structural configurations, 30 of them were handled in the framework of this study. The structural ...

  7. Spectroscopic data

    CERN Document Server

    Melzer, J

    1976-01-01

    During the preparation of this compilation, many people contributed; the compilers wish to thank all of them. In particular they appreciate the efforts of V. Gilbertson, the manuscript typist, and those of K. C. Bregand, J. A. Kiley, and W. H. McPherson, who gave editorial assistance. They would like to thank Dr. J. R. Schwartz for his cooperation and encouragement. In addition, they extend their grati­ tude to Dr. L. Wilson of the Air Force Weapons Laboratory, who gave the initial impetus to this project. v Contents I. I ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . 11. Organization ofthe Spectroscopic Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Methods of Production and Experimental Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Band Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2...

  8. Vibrational spectroscopic (FT-IR, FT-Raman) and quantum mechanical study of 4-(2-chlorophenyl)-2-ethyl-9-methyl-6H-thieno[3,2-f] [1,2,4]triazolo[4,3-a][1,4] diazepine

    Science.gov (United States)

    Kuruvilla, Tintu K.; Prasana, Johanan Christian; Muthu, S.; George, Jacob

    2018-04-01

    The spectroscopic properties of 4-(2-chlorophenyl)-2-ethyl-9-methyl-6H-thieno [3,2-f] [1,2,4] triazolo [4,3-a] [1,4] diazepine were investigated in the present study using FT-IR and FT-Raman techniques. The results obtained were compared with quantum mechanical methods, as it serves as an important tool in interpreting and predicting vibrational spectra. The optimized molecular geometry, the vibrational wavenumbers, the infrared intensities and Raman scattering were calculated using density functional theory B3LYP method with 6-311++g (d,p) basis set. All the experimental results were in line with the theoretical data. The molecular electrostatic potential (MEP) and HOMO LUMO energies of the title compound were accounted. The results indicated that the title compound has a lower softness value (0.27) and high electrophilicity index (4.98) hence describing its biological activity. Further, natural bond orbital was also analyzed as part of the work. Fukui functions were calculated in order to explain the chemical selectivity or the reactivity site in 4-(2-chlorophenyl)-2-ethyl-9-methyl-6H-thieno [3,2-f] [1,2,4] triazolo [4,3-a] [1,4] diazepine. The thermodynamic properties of the title compound were closely examined at different temperatures. It revealed the correlations between heat capacity (C), entropy (S) and enthalpy changes (H) with temperatures. The paper further explains that the title compound can act as good antidepressant through molecular docking studies.

  9. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor); Lane, Arthur L. (Inventor)

    2017-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  10. Surface-enhanced FAST CARS: en route to quantum nano-biophotonics

    Science.gov (United States)

    Voronine, Dmitri V.; Zhang, Zhenrong; Sokolov, Alexei V.; Scully, Marlan O.

    2018-02-01

    Quantum nano-biophotonics as the science of nanoscale light-matter interactions in biological systems requires developing new spectroscopic tools for addressing the challenges of detecting and disentangling weak congested optical signals. Nanoscale bio-imaging addresses the challenge of the detection of weak resonant signals from a few target biomolecules in the presence of the nonresonant background from many undesired molecules. In addition, the imaging must be performed rapidly to capture the dynamics of biological processes in living cells and tissues. Label-free non-invasive spectroscopic techniques are required to minimize the external perturbation effects on biological systems. Various approaches were developed to satisfy these requirements by increasing the selectivity and sensitivity of biomolecular detection. Coherent anti-Stokes Raman scattering (CARS) and surface-enhanced Raman scattering (SERS) spectroscopies provide many orders of magnitude enhancement of chemically specific Raman signals. Femtosecond adaptive spectroscopic techniques for CARS (FAST CARS) were developed to suppress the nonresonant background and optimize the efficiency of the coherent optical signals. This perspective focuses on the application of these techniques to nanoscale bio-imaging, discussing their advantages and limitations as well as the promising opportunities and challenges of the combined coherence and surface enhancements in surface-enhanced coherent anti-Stokes Raman scattering (SECARS) and tip-enhanced coherent anti-Stokes Raman scattering (TECARS) and the corresponding surface-enhanced FAST CARS techniques. Laser pulse shaping of near-field excitations plays an important role in achieving these goals and increasing the signal enhancement.

  11. Prospects for in vivo Raman spectroscopy

    International Nuclear Information System (INIS)

    Hanlon, E.B.; Manoharan, R.; Koo, T.-W.; Shafer, K.E.; Motz, J.T.; Fitzmaurice, M.; Kramer, J.R.; Itzkan, I.; Dasari, R.R.; Feld, M.S.

    2000-01-01

    Raman spectroscopy is a potentially important clinical tool for real-time diagnosis of disease and in situ evaluation of living tissue. The purpose of this article is to review the biological and physical basis of Raman spectroscopy of tissue, to assess the current status of the field and to explore future directions. The principles of Raman spectroscopy and the molecular level information it provides are explained. An overview of the evolution of Raman spectroscopic techniques in biology and medicine, from early investigations using visible laser excitation to present-day technology based on near-infrared laser excitation and charge-coupled device array detection, is presented. State-of-the-art Raman spectrometer systems for research laboratory and clinical settings are described. Modern methods of multivariate spectral analysis for extracting diagnostic, chemical and morphological information are reviewed. Several in-depth applications are presented to illustrate the methods of collecting, processing and analysing data, as well as the range of medical applications under study. Finally, the issues to be addressed in implementing Raman spectroscopy in various clinical applications, as well as some long-term directions for future study, are discussed. (author)

  12. Analysis of molecular structure, spectroscopic properties (FT-IR, micro-Raman and UV-vis) and quantum chemical calculations of free and ligand 2-thiopheneglyoxylic acid in metal halides (Cd, Co, Cu, Ni and Zn).

    Science.gov (United States)

    Gökce, Halil; Bahçeli, Semiha

    2013-12-01

    In this study, molecular geometries, experimental vibrational wavenumbers, electronic properties and quantum chemical calculations of 2-thiopheneglyoxylic acid molecule, (C6H4O3S), and its metal halides (Cd, Co, Cu, Ni and Zn) which are used as pharmacologic agents have been investigated experimentally by FT-IR, micro-Raman and UV-visible spectroscopies and elemental analysis. Meanwhile the vibrational calculations were verified by DFT/B3LYP method with 6-311++G(d,p) and LANL2DZ basis sets in the ground state, for free TPGA molecule and its metal halide complexes, respectively, for the first time. The calculated fundamental vibrational frequencies for the title compounds are in a good agreement with the experimental data. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO analysis and molecular docking study of 1-hydroxy-4,5,8-tris(4-methoxyphenyl) anthraquinone

    Science.gov (United States)

    Renjith, R.; Sheena Mary, Y.; Tresa Varghese, Hema; Yohannan Panicker, C.; Thiemann, Thies; Shereef, Anas; Al-Saadi, Abdulaziz A.

    2015-12-01

    FT-IR and FT-Raman spectra of 1-hydroxy-4,5,8-tris(4-methoxyphenyl)anthraquinone were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations were used to assign the vibrational bands obtained experimentally. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. From the MEP plot it is clear that the negative electrostatic potential regions are mainly localized over carbonyl group. There is some evidence of a region of negative electrostatic potential due to π-electron density of the benzo groups. Molecular docking study shows that methoxy groups attached to the phenyl rings and hydroxyl group are crucial for binding and the title compound might exhibit inhibitory activity against PI3K and may act as an anti-neoplastic agent.

  14. Raman spectroscopic study of structure and crystallisation behaviour of MoO3-La2O3-B2O3 and MoO3-ZnO-B2O3 glasses

    Science.gov (United States)

    Aleksandrov, L.; Komatsu, T.; Nagamine, K.; Oishi, K.

    2011-03-01

    In this study, we focus on the structure and crystallization behavior of MoO3-La2O3-B2O3 and MoO3-ZnO-B2O3 glasses. Glasses of both systems were prepared by a melt-quenching method. The thermal stability of the glasses was examined using differential thermal anaysis (DTA) measurements, and the crystalline phases formed by heat treatments were identified by X-ray diffraction (XRD) analysis. Raman scattering spectra at room temperature for the glasses and crystallized samples were measured with a laser microscope operated with an Ar+ (wavelength: 488 nm) laser. DTA measurements indicated that the thermal stability against crystallization of the glasses decreases drastically with increasing MoO3 content. XRD analysis confirmed that crystallization at 600°C for 3 h of glass with the nominal composition of 50MoO3-25La2O3-25B2O3 resulted in the formation of monoclinic LaMoBO6. Crystallization of 50ZnO-xMoO3-(50-x)B2O3 glasses formed triclinic α-ZnMoO4 as an initial crystalline phase. Moreover, for 30 mol% MoO3 glass, transmission electron microscopy observations showed the formation of α-ZnMoO4 nanocrystals with a diameter of ~ 5 nm. Raman bands at 860, 930 and 950 cm-1 suggested that the coordination state of Mo6+ ions in the glasses were mainly (MoO4)2- tetrahedral units. Therefore, MoO3-containing glasses have good potential for optical applications.

  15. Whispering Gallery Optical Resonator Spectroscopic Probe and Method

    Science.gov (United States)

    Anderson, Mark S. (Inventor)

    2014-01-01

    Disclosed herein is a spectroscopic probe comprising at least one whispering gallery mode optical resonator disposed on a support, the whispering gallery mode optical resonator comprising a continuous outer surface having a cross section comprising a first diameter and a second diameter, wherein the first diameter is greater than the second diameter. A method of measuring a Raman spectrum and an Infra-red spectrum of an analyte using the spectroscopic probe is also disclosed.

  16. Spectroscopic study

    International Nuclear Information System (INIS)

    Flores, M.; Rodriguez, R.; Arroyo, R.

    1999-01-01

    This work is focused about the spectroscopic properties of a polymer material which consists of Polyacrylic acid (Paa) doped at different concentrations of Europium ions (Eu 3+ ). They show that to stay chemically joined with the polymer by a study of Nuclear Magnetic Resonance (NMR) of 1 H, 13 C and Fourier Transform Infrared Spectroscopy (Ft-IR) they present changes in the intensity of signals, just as too when this material is irradiated at λ = 394 nm. In according with the results obtained experimentally in this type of materials it can say that is possible to unify chemically the polymer with this type of cations, as well as, varying the concentration of them, since that these are distributed homogeneously inside the matrix maintaining its optical properties. These materials can be obtained more quickly and easy in solid or liquid phase and they have the best conditions for to make a quantitative analysis. (Author)

  17. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR insights, electronic profiling and DFT computations on ({(E-[3-(1H-imidazol-1-yl-1-phenylpropylidene] amino}oxy(4-nitrophenylmethanone, an imidazole-bearing anti-Candida agent

    Directory of Open Access Journals (Sweden)

    Al-Wahaibi Lamya H.

    2018-02-01

    Full Text Available The anti-Candida agent, ({(E-[3-(1H-imidazol-1-yl-1-phenylpropylidene]amnio}oxy(4-nitropheny methanone (IPAONM, was subjected to comprehensive spectroscopic (FT-IR, FT-Raman, UV–Vis 1H and 13C NMR characterization as well as Hartree Fock and density functional theory computation studies. The selected optimized geometric bond lengths and bond angles of the IPAONM molecule were compared with the experimental values. The calculated wavenumbers have been scaled and compared with the experimental spectra. Mulliken charges and natural bond orbital analysis of the title molecule were calculated and interpreted. The energy and oscillator strengths of the IPAONM molecule were calculated by time-dependent density functional theory (TD-DFT. In addition, frontier molecular orbitals and molecular electrostatic potential diagram of the title compound were computed and analyzed. A study on the electronic properties, such as HOMO, HOMO-1, LUMO and LUMO+1 energies was carried out using TD-DFT approach. The 1H and 13C NMR chemical shift values of the title compound were calculated by the gauge independent atomic orbital method and compared with the experimental results.

  18. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    Science.gov (United States)

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  19. Spectroscopic (FT-IR, FT-Raman, and UV-visible) and quantum chemical studies on molecular geometry, Frontier molecular orbitals, NBO, NLO and thermodynamic properties of 1-acetylindole.

    Science.gov (United States)

    Shukla, Vikas K; Al-Abdullah, Ebtehal S; El-Emam, Ali A; Sachan, Alok K; Pathak, Shilendra K; Kumar, Amarendra; Prasad, Onkar; Bishnoi, Abha; Sinha, Leena

    2014-12-10

    Quantum chemical calculations of ground state energy, geometrical structure and vibrational wavenumbers of 1-acetylindole were carried out using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. The FT-IR and FT-Raman spectra were recorded in the condensed state. The fundamental vibrational wavenumbers were calculated and a good correlation between experimental and scaled calculated wavenumbers has been accomplished. Electric dipole moment, polarizability and first static hyperpolarizability values of 1-acetylindole have been calculated at the same level of theory and basis set. The results show that the 1-acetylindole molecule possesses nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. UV-Visible spectrum of the molecule was recorded in the region 200-500nm and the electronic properties like HOMO and LUMO energies and composition were obtained using TD-DFT method. The calculated energies and oscillator strengths are in good correspondence with the experimental data. The thermodynamic properties of the compound under investigation were calculated at different temperatures. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Spectroscopic studies (FT-IR, FT-Raman, UV-Visible), normal co-ordinate analysis, first-order hyperpolarizability and HOMO, LUMO studies of 3,4-dichlorobenzophenone by using Density Functional Methods.

    Science.gov (United States)

    Venkata Prasad, K; Samatha, K; Jagadeeswara Rao, D; Santhamma, C; Muthu, S; Mark Heron, B

    2015-01-01

    The vibrational frequencies of 3,4-dichlorobenzophenone (DCLBP) were obtained from the FT-IR and Raman spectral data, and evaluated based on the Density Functional Theory using the standard method B3LYP with 6-311+G(d,p) as the basis set. On the basis of potential energy distribution together with the normal-co-ordinate analysis and following the scaled quantum mechanical force methodology, the assignments for the various frequencies were described. The values of the electric dipole moment (μ) and the first-order hyperpolarizability (β) of the molecule were computed. The UV-absorption spectrum was also recorded to study the electronic transitions. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The NBO analysis, to study the intramolecular hyperconjugative interactions, was carried out. Mulliken's net charges were evaluated. The MEP and thermodynamic properties were also calculated. The electron density-based local reactivity descriptor, such as Fukui functions, was calculated to explain the chemical selectivity or reactivity site in 3,4-dichlorobenzophenone. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) profiling and computational studies on methyl 5-methoxy-1H-indole-2-carboxylate: A potential precursor to biologically active molecules

    Science.gov (United States)

    Almutairi, Maha S.; Xavier, S.; Sathish, M.; Ghabbour, Hazem A.; Sebastian, S.; Periandy, S.; Al-Wabli, Reem I.; Attia, Mohamed I.

    2017-04-01

    Methyl 5-methoxy-1H-indole-2-carboxylate (MMIC) was prepared via esterification of commercially available 5-methoxyindole-2-carboxylic acid. The title molecule MMIC was characterised using FT-IR and FT-Raman in the ranges of 4000-500 and 4000-50 cm-1, respectively. The fundamental modes of the vibrations were assigned and the UV-visible spectrum of the MMIC molecule was recorded in the range of 200-400 nm to explore its electronic nature. The HOMO-LUMO energy distribution was calculated and the bonding and anti-bonding structures of the title molecule were studied and analysed using the natural bond orbital (NBO) approach. The reactivity of the MMIC molecule was also investigated and both the positive and negative centres of the molecule were identified using chemical descriptors and molecular electrostatic potential (MEP) analysis. The chemical shifts of the 1H and 13C NMR spectra were noted and the magnetic field environment of the MMIC molecule are discussed. The non-linear optical (NLO) properties of the title molecule were studied based on its calculated values of polarisability and hyperpolarisability. All computations were obtained by DFT methods using the 6-311++G (d,p) basis set.

  2. Raman Spectroscopic Measurements of Dermal Carotenoids in Breast Cancer Operated Patients Provide Evidence for the Positive Impact of a Dietary Regimen Rich in Fruit and Vegetables on Body Oxidative Stress and BC Prognostic Anthropometric Parameters: A Five-Year Study.

    Science.gov (United States)

    Perrone, A; Pintaudi, A M; Traina, A; Carruba, G; Attanzio, A; Gentile, C; Tesoriere, L; Livrea, M A

    2016-01-01

    Dermal carotenoids are a feasible marker of the body antioxidative network and may reveal a moderate to severe imbalance of the redox status, thereby providing indication of individual oxidative stress. In this work noninvasive Resonance Raman Spectroscopy (RRS) measurements of skin carotenoids (skin carotenoid score (SCS)) were used to provide indications of individual oxidative stress, each year for five years, in 71 breast cancer (BC) patients at high risk of recurrence. Patients' SCS has been correlated with parameters relevant to BC risk, waist circumference (WC), and body mass index (BMI), in the aim of monitoring the effect of a dietary regimen intended to positively affect BC risk factors. The RRS methodological approach in BC patients appeared from positive correlation between patients' SCS and blood level of lycopene. The level of skin carotenoids was inversely correlated with the patients' WC and BMI. At the end of the 5 y observation BC patients exhibited a significant reduction of WC and BMI and increase of SCS, when strictly adhering to the dietary regimen. In conclusion, noninvasive measurements of skin carotenoids can (i) reveal an oxidative stress condition correlated with parameters of BC risk and (ii) monitor dietary-related variations in BC patients.

  3. Raman Spectroscopic Measurements of Dermal Carotenoids in Breast Cancer Operated Patients Provide Evidence for the Positive Impact of a Dietary Regimen Rich in Fruit and Vegetables on Body Oxidative Stress and BC Prognostic Anthropometric Parameters: A Five-Year Study

    Directory of Open Access Journals (Sweden)

    A. Perrone

    2016-01-01

    Full Text Available Dermal carotenoids are a feasible marker of the body antioxidative network and may reveal a moderate to severe imbalance of the redox status, thereby providing indication of individual oxidative stress. In this work noninvasive Resonance Raman Spectroscopy (RRS measurements of skin carotenoids (skin carotenoid score (SCS were used to provide indications of individual oxidative stress, each year for five years, in 71 breast cancer (BC patients at high risk of recurrence. Patients’ SCS has been correlated with parameters relevant to BC risk, waist circumference (WC, and body mass index (BMI, in the aim of monitoring the effect of a dietary regimen intended to positively affect BC risk factors. The RRS methodological approach in BC patients appeared from positive correlation between patients’ SCS and blood level of lycopene. The level of skin carotenoids was inversely correlated with the patients’ WC and BMI. At the end of the 5 y observation BC patients exhibited a significant reduction of WC and BMI and increase of SCS, when strictly adhering to the dietary regimen. In conclusion, noninvasive measurements of skin carotenoids can (i reveal an oxidative stress condition correlated with parameters of BC risk and (ii monitor dietary-related variations in BC patients.

  4. Geometric phase and entanglement of Raman photon pairs in the presence of photonic band gap

    International Nuclear Information System (INIS)

    Berrada, K.; Ooi, C. H. Raymond; Abdel-Khalek, S.

    2015-01-01

    Robustness of the geometric phase (GP) with respect to different noise effects is a basic condition for an effective quantum computation. Here, we propose a useful quantum system with real physical parameters by studying the GP of a pair of Stokes and anti-Stokes photons, involving Raman emission processes with and without photonic band gap (PBG) effect. We show that the properties of GP are very sensitive to the change of the Rabi frequency and time, exhibiting collapse phenomenon as the time becomes significantly large. The system allows us to obtain a state which remains with zero GP for longer times. This result plays a significant role to enhance the stabilization and control of the system dynamics. Finally, we investigate the nonlocal correlation (entanglement) between the pair photons by taking into account the effect of different parameters. An interesting correlation between the GP and entanglement is observed showing that the PBG stabilizes the fluctuations in the system and makes the entanglement more robust against the change of time and frequency

  5. In vivo coherent Raman imaging of the melanomagenesis-associated pigment pheomelanin

    Science.gov (United States)

    Wang, Hequn; Osseiran, Sam; Igras, Vivien; Nichols, Alexander J.; Roider, Elisabeth M.; Pruessner, Joachim; Tsao, Hensin; Fisher, David E.; Evans, Conor L.

    2016-11-01

    Melanoma is the most deadly form of skin cancer with a yearly global incidence over 232,000 patients. Individuals with fair skin and red hair exhibit the highest risk for developing melanoma, with evidence suggesting the red/blond pigment known as pheomelanin may elevate melanoma risk through both UV radiation-dependent and -independent mechanisms. Although the ability to identify, characterize, and monitor pheomelanin within skin is vital for improving our understanding of the underlying biology of these lesions, no tools exist for real-time, in vivo detection of the pigment. Here we show that the distribution of pheomelanin in cells and tissues can be visually characterized non-destructively and noninvasively in vivo with coherent anti-Stokes Raman scattering (CARS) microscopy, a label-free vibrational imaging technique. We validated our CARS imaging strategy in vitro to in vivo with synthetic pheomelanin, isolated melanocytes, and the Mc1re/e, red-haired mouse model. Nests of pheomelanotic melanocytes were observed in the red-haired animals, but not in the genetically matched Mc1re/e; Tyrc/c (“albino-red-haired”) mice. Importantly, samples from human amelanotic melanomas subjected to CARS imaging exhibited strong pheomelanotic signals. This is the first time, to our knowledge, that pheomelanin has been visualized and spatially localized in melanocytes, skin, and human amelanotic melanomas.

  6. Experimental spectroscopic (FTIR, FT-Raman, FT-NMR, UV-Visible) and DFT studies of 1-ethyl-1,4-dihydro-7-methyl-4oxo-1,8 napthyridine-3-carboxylic acids.

    Science.gov (United States)

    Muthu, S; Elamurugu Porchelvi, E

    2013-12-01

    The solid phase FTIR and FT-Raman spectra of 1-ethyl-1,4-dihydro-7-methyl-4oxo-1,8 napthyridine-3-carboxylic acid (EDMONCA) have been recorded in the regions 4000-500 and 4000-400 cm(-1) respectively. The equilibrium geometry, harmonic vibrational frequencies have been investigated by DFT/B3LYP and B3PW91 methods with 6-311G (d,p) basis set. The different between the observed and scaled wave number values of most of the fundamental is very small. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFFM). Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. UV-Visible spectrum of the compound was recorded and the electronic properties HOMO and LOMO energies were measured. The electric dipole moment (μD) and first hyperpolarizability (βtot) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results also show that the EDMONCA molecule may have microscopic nonlinear optics (NLO) behavior with non-zero values. (1)H and (13)C NMR spectra were recorded and (1)H and (13)C nuclear magnetic resonance chemical shift of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. Thermal stability of EDMONCA was studied by thermogravimetric analysis (TGA). Next Fukui function was calculated to explain the chemical selectivity or reactivity site in EDMONCA. Finally molecular electrostatic potential (MEP) and other molecular properties were performed. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Infrared, Raman and laser fluorescence studies on large molecules

    International Nuclear Information System (INIS)

    Venkateswaran, Sugandhi

    2000-01-01

    In the present thesis, infrared and Raman spectroscopic studies on large molecules, molecular assemblies and crystalline solids, as a function of temperature, pressure and added materials have been carried out. Spectral changes observed in our studies are interpreted in terms of intermolecular interaction, phase transition and conformational changes taking place in the molecules studied

  8. Raman spectroscopy in the analysis of cellulose nanomaterials

    Science.gov (United States)

    Umesh P. Agarwal

    2017-01-01

    Cellulose nanomaterials (CNs) are new types of materials derived from celluloses and offer unique challenges and opportunities for Raman spectroscopic investigations. CNs can be classified into the categories of cellulose nanocrystals (CNCs, also known as cellulose whisker) and cellulose nanofibrils (CNFs, also known as nanofibrillated cellulose or NFCs) which when...

  9. Spectroscopic characterization of manganese-doped alkaline earth ...

    Indian Academy of Sciences (India)

    Alkaline earth lead zinc phosphate glasses doped with Mn(II) are characterized by spectroscopic techniques like X-ray diffraction (XRD), UV–visible, differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and Raman. Optical absorption spectrum exhibits four ...

  10. An empirical evaluation of three vibrational spectroscopic methods for detection of aflatoxins in maize.

    Science.gov (United States)

    Lee, Kyung-Min; Davis, Jessica; Herrman, Timothy J; Murray, Seth C; Deng, Youjun

    2015-04-15

    Three commercially available vibrational spectroscopic techniques, including Raman, Fourier transform near infrared reflectance (FT-NIR), and Fourier transform infrared (FTIR) were evaluated to help users determine the spectroscopic method best suitable for aflatoxin analysis in maize (Zea mays L.) grain based on their relative efficiency and predictive ability. Spectral differences of Raman and FTIR spectra were more marked and pronounced among aflatoxin contamination groups than those of FT-NIR spectra. From the observations and findings in our current and previous studies, Raman and FTIR spectroscopic methods are superior to FT-NIR method in terms of predictive power and model performance for aflatoxin analysis and they are equally effective and accurate in predicting aflatoxin concentration in maize. The present study is considered as the first attempt to assess how spectroscopic techniques with different physical processes can influence and improve accuracy and reliability for rapid screening of aflatoxin contaminated maize samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Planetary Laser Raman Spectroscopy for Surface Exploration on C/D-Type Asteroids — A Case Study

    Science.gov (United States)

    Kong, W. G.; Wang, A.

    2010-03-01

    A laser Raman spectroscopic study on Murchison and Allende meteorites provide detailed information on major, minor, and trace minerals information. This study demonstrates the feasibility of LR for surface exploration missions to C/D-type asteroids.

  12. First principal studies of spectroscopic (IR and Raman, UV-visible), molecular structure, linear and nonlinear optical properties of L-arginine p-nitrobenzoate monohydrate (LANB): A new non-centrosymmetric material

    Science.gov (United States)

    Shkir, Mohd.; AlFaify, S.; Abbas, Haider; Muhammad, Shabbir

    2015-08-01

    In current work, the authors have been applied the density functional theory (DFT) using B3LYP and CAM-B3LYP exchange-correlation functional with 6-31G∗ basis set on L-arginine p-nitrobenzoate monohydrate (LANB) molecule for the first time to optimize its geometry and study the spectroscopic, electronic structure, nonlinear optical properties. Vibrational modes were found in good agreement with experimental reports. The calculated UV spectra by B3LYP/6-31G∗ and CAM-B3LYP/6-31G∗ level of theory shows an electronic transition at ∼268 nm (4.63 eV) and 264 nm (4.70 eV) respectively. To explain the charge interaction taking place within the molecule highest occupied molecular orbital and lowest unoccupied molecular orbital were analyzed and their calculated energy gap was found to be 4.3 eV with an oscillatory strength 0.3796 at B3LYP/6-31G∗ level of theory. The dipole moment (μtot), average and anisotropy of polarizability (αtot, Δα) and static and total first hyperpolarizability (β0, βtot) values were calculated. The value of μtot and βtot are found to be 4.124D and 1.630 × 10-30 esu and 4.127D and 1.133 × 10-30 esu using B3LYP/6-31G∗ and CAM-B3LYP/6-31G∗ functional respectively. The value of βtot is >4 and >3 times higher than prototype urea molecule calculated at both level of theory, respectively. The molecular electrostatic potential (MEP), frontier molecular orbital's (FMOs), global reactivity descriptors and thermodynamic properties are also calculated and discussed. The properties of LANB calculated at B3LYP are in good correlation with experimental than the CAM-B3LYP level of theory. The obtained results show that LANB molecule can be treated as a good candidate for nonlinear optical devices.

  13. Integrated confocal Raman probe combined with a free-form reflector based lab-on-chip

    Science.gov (United States)

    Liu, Qing; Barbieri, Giancarlo; Thienpont, Hugo; Ottevaere, Heidi

    2017-08-01

    Raman spectroscopy is a powerful tool for analytical measurements in many applications. Traditional Raman spectroscopic analyses require bulky equipment, considerable time of signal acquisition and manual sampling of substances under test. In this paper, we take a step from bulky and manual consuming laboratory testing towards lab-on-chip (LOC) analyses. We miniaturize the Raman spectroscopic system by combining a free-form reflector based polymer LOC with a customized Raman probe. By using the confocal detection principle, we aim to enhance the detection of the Raman signals from the substance of interest due to the suppression of the background Raman signal from the polymer of the chip. Next to the LOC we miniaturize the external optical components, surrounding the reflector embedding optofluidic chip, and assemble these in a Raman probe. We evaluate the misalignment tolerance of internal optics (LOC) and external optics (Raman probe) by non-sequential ray tracing which shows that off-axis misalignment is around ±400μm and the maximum working distance of our Raman probe is 71mm. Using this probe, the system could be implemented as a portable reader unit containing the external optics, in which a low-cost, robust and mass manufacturable microfluidic LOC containing a freeform reflector is inserted, to enable confocal Raman spectroscopy measurements.

  14. Application of Raman Spectroscopy for Quality Monitoring in the Meat Processing Industry

    DEFF Research Database (Denmark)

    Berhe, Daniel Tsegay

    The objective of this thesis was to test the potential application of Raman spectroscopy for quality monitoring in the meat processing industry. Raman spectroscopy is a spectroscopic technique, which can provide rapid chemical information at the molecular level. It can, therefore, be used for non......-destructive quality monitoring in the meat processing industry as it requires no further sample preparation. Water, which is the main component of meat, is also not a problem for Raman spectroscopic measurement because water is a poor Raman scatter. Two major product quality related issues, cooking of meat and fat...... in water bath then stored under vacuum packaging for day- 0, -4 and -8 (paper-II). Secondly, the thesis work examined the use of Raman spectroscopy in combination with chemometrics to determine the gross FA parameters and individual FAs in pork backfat. Non-targeted predictions of highly collinear...

  15. Coherent Raman spectroscopy

    CERN Document Server

    Eesley, G L

    1981-01-01

    Coherent Raman Spectroscopy provides a unified and general account of the fundamental aspects of nonlinear Raman spectroscopy, also known as coherent Raman spectroscopy. The theoretical basis from which coherent Raman spectroscopy developed is described, along with its applications, utility, and implementation as well as advantages and disadvantages. Experimental data which typifies each technique is presented. This book is comprised of four chapters and opens with an overview of nonlinear optics and coherent Raman spectroscopy, followed by a discussion on nonlinear transfer function of matter

  16. Spectroscopic and theoretical investigations of phenolic acids in white wines.

    Science.gov (United States)

    Martin, Coralie; Bruneel, Jean-Luc; Castet, Frédéric; Fritsch, Alain; Teissedre, Pierre-Louis; Jourdes, Michael; Guillaume, François

    2017-04-15

    Model solutions of white wines containing phenolic acids have been investigated by means of UV-vis, laser induced fluorescence and Raman spectroscopic techniques. In order to interpret the spectra, density functional theory calculations of phenolic acids have been performed. This work demonstrates that only hydroxynamic acids are in resonance with a laser excitation line with 325nm wavelength and are therefore at the origin of the strong enhancement of the Raman light scattering. Real white wines also display such resonance Raman scattering so that their content in hydroxycinnamic acids may be quite precisely determined. The analysis of the Raman spectrum of a real dry white wine reveals qualitatively the preponderance in its composition of p-coumaric and caftaric acids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Raman spectroscopy in cervical cancers: An update

    Directory of Open Access Journals (Sweden)

    S Rubina

    2015-01-01

    Full Text Available Cervical cancer is the third most common cancer among women worldwide. Developing countries contribute more than 80% towards global burden. Over the last 2 decades, Raman spectroscopy (RS has been actively pursued for cervical cancer detection. In view of latest development in Raman spectroscopic applications in cervical cancers, especially in vivo studies, an update of the same is presented in this article. This articles opens with a brief note on Anatomy of cervix followed by Etiology, and conventional Screening and Diagnosis of Cervical cancers. In subsequent sections, brief description of Theory and Instrumentation of RS is followed by a review of recent developments in cervical cancer detection; with emphasis on cell lines, exfoliated cells, ex vivo and in vivo, and therapeutic response monitoring applications in cervical cancer.

  18. Application of Raman spectroscopy for cancer diagnosis

    International Nuclear Information System (INIS)

    Krishnakumar, N.

    2011-01-01

    Cancer is the second leading causes of death next to heart diseases, Half of all cancer cases occur in developing countries. The conventional histopathology is usually the most trustable gold standard for pre-cancer and cancer diagnosis. However, the applicability of this method is more or less restricted because of the requirement of removing human tissues and the difficulty of real time diagnosis. Recently, there has been increased interest in 'optical biopsy' system using tissue spectroscopy to establish the pathological changes. Among optical based methods, Raman spectroscopy is a unique vibrational spectroscopic technique capable of probing biomolecular structures and conformation of tissues, and has excelled in the early detection of pre-cancer and cancer in the number of organs with high diagnostic specificity. Raman spectroscopy offers certain distinct advantages over than other optical diagnostic techniques such as high spatial resolution, use of less harmful NIR radiation, less or no sample preparation, no influence of water bands which facilitates in vivo/in situ measurements. This makes Raman spectroscopy also very useful for biomedical applications. Several research groups have demonstrated the efficacy of this technique in biomedical applications. The background and principle of these techniques will be discussed with some examples and discussions on how Raman spectroscopy can act as a promising technique for rapid in vivo diagnosis and detection of various cancers at the molecular level. (author)

  19. Raman Spectra of Nanodiamonds: New Treatment Procedure Directed for Improved Raman Signal Marker Detection

    Directory of Open Access Journals (Sweden)

    Raoul R. Nigmatullin

    2013-01-01

    Full Text Available Detonation nanodiamonds (NDs have shown to be promising agents in several industries, ranging from electronic to biomedical applications. These NDs are characterized by small particle size ranging from 3 to 6 nm, while having a reactive surface and a stable inert core. Nanodiamonds can exhibit novel intrinsic properties such as fluorescence, high refractive index, and unique Raman signal making them very attractive imaging agents. In this work, we used several nanodiamond preparations for Raman spectroscopic studies. We exposed these nanodiamonds to increasing temperature treatments at constant heating rates (425–575°C aiding graphite release. We wanted to correlate changes in the nanodiamond surface and properties with Raman signal which could be used as a detection marker. These observations would hold potential utility in biomedical imaging applications. First, the procedure of optimal linear smoothing was applied successfully to eliminate the high-frequency fluctuations and to extract the smoothed Raman spectra. After that we applied the secondary Fourier transform as the fitting function based on some significant set of frequencies. The remnant noise was described in terms of the beta-distribution function. We expect this data treatment to provide better results in biomolecule tracking using nanodiamond base Raman labeling.

  20. Confocal Raman Microscopy

    CERN Document Server

    Dieing, Thomas; Toporski, Jan

    2011-01-01

    Confocal Raman Microscopy is a relatively new technique that allows chemical imaging without specific sample preparation. By integrating a sensitive Raman spectrometer within a state-of-the-art microscope, Raman microscopy with a spatial resolution down to 200nm laterally and 500nm vertically can be achieved using visible light excitation. Recent developments in detector and computer technology as well as optimized instrument design have reduced integration times of Raman spectra by orders of magnitude, so that complete images consisting of tens of thousands of Raman spectra can be acquired in seconds or minutes rather than hours, which used to be standard just one decade ago. The purpose of this book is to provide the reader a comprehensive overview of the rapidly developing field of Confocal Raman Microscopy and its applications.

  1. In vivo Raman spectroscopy of cervix cancers

    Science.gov (United States)

    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.

  2. Characterization of a hazardous eyeliner (kohl) by confocal Raman microscopy

    International Nuclear Information System (INIS)

    Jallad, Karim N.; Hedderich, Hartmut G.

    2005-01-01

    A new method of analyzing kohl, a cosmetic eyeliner, using confocal Raman microscopy is reported. This technique offers an important alternative to conventional spectroscopic techniques that provide elemental/atomic composition. Raman spectra of three kohl samples have been measured between 150 and 3000 cm -1 at room temperature. The main component of two kohl samples was found to be lead(II) sulfide (PbS). Kohl is used as a traditional cosmetic and remedy in the Middle East, Far East, and Northern Africa. Since kohl products contain very high concentrations of lead, they constitute a risk for public health, particularly for children

  3. V V Raman

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. V V Raman. Articles written in Resonance – Journal of Science Education. Volume 13 Issue 6 June 2008 pp 596-605 Reflections. The Scientific Enterprise - Science: Some Definitions and Views · V V Raman · More Details Fulltext PDF. Volume 13 Issue 8 August ...

  4. Raman crystallography of RNA.

    Science.gov (United States)

    Gong, Bo; Chen, Jui-Hui; Yajima, Rieko; Chen, Yuanyuan; Chase, Elaine; Chadalavada, Durga M; Golden, Barbara L; Carey, Paul R; Bevilacqua, Philip C

    2009-10-01

    Raman crystallography is the application of Raman spectroscopy to single crystals. This technique has been applied to a variety of protein molecules where it has provided unique information about biopolymer folding, substrate binding, and catalysis. Here, we describe the application of Raman crystallography to functional RNA molecules. RNA represents unique opportunities and challenges for Raman crystallography. One issue that confounds studies of RNA is its tendency to adopt multiple non-functional folds. Raman crystallography has the advantage that it isolates a single state of the RNA within the crystal and can evaluate its fold, metal ion binding properties (ligand identity, stoichiometry, and affinity), proton binding properties (identity, stoichiometry, and affinity), and catalytic potential. In particular, base-specific stretches can be identified and then associated with the binding of metal ions and protons. Because measurements are carried out in the hanging drop at ambient, rather than cryo, conditions and because RNA crystals tend to be approximately 70% solvent, RNA dynamics and conformational changes become experimentally accessible. This review focuses on experimental setup and procedures, acquisition and interpretation of Raman data, and determination of physicochemical properties of the RNA. Raman crystallographic and solution biochemical experiments on the HDV RNA enzyme are summarized and found to be in excellent agreement. Remarkably, characterization of the crystalline state has proven to help rather than hinder functional characterization of functional RNA, most likely because the tendency of RNA to fold heterogeneously is limited in a crystalline environment. Future applications of Raman crystallography to RNA are briefly discussed.

  5. Karthik Raman Nagasuma Chandra

    Indian Academy of Sciences (India)

    Karthik Raman1 Nagasuma Chandra2. Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Switzerland; Bioinformatics Centre, Raman building, Indian Institute of Science, Bangalore 560 012, India. Resonance – Journal of Science Education. Current Issue : Vol. 23, Issue 2. Current Issue

  6. Raman fiber lasers

    CERN Document Server

    2017-01-01

    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  7. Hydrate formation during wet granulation studied by spectroscopic methods and multivariate analysis

    DEFF Research Database (Denmark)

    Jørgensen, Anna; Rantanen, Jukka; Karjalainen, Milja

    2002-01-01

    PURPOSE: The aim was to follow hydrate formation of two structurally related drugs, theophylline and caffeine, during wet granulation using fast and nondestructive spectroscopic methods. METHODS: Anhydrous theophylline and caffeine were granulated with purified water. Charge-coupled device (CCD......) Raman spectroscopy was compared with near-infrared spectroscopy (NIR) in following hydrate formation of drugs during wet granulation (off-line). To perform an at-line process analysis, the effect of water addition was monitored by NIR spectroscopy and principal components analysis (PCA). The changes...... in the crystal arrangements were verified by using X-ray powder diffraction (XRPD). RESULTS: Hydrate formation of theophylline and caffeine could be followed by CCD Raman spectroscopy. The NIR and Raman spectroscopic results were consistent with each other. NIR revealed the state of water, and Raman spectroscopy...

  8. Infrared and Raman spectroscopic studies of glasses with NASICON ...

    Indian Academy of Sciences (India)

    Unknown

    The glass spectrum of NTP consists of all the important features present in the spectrum of the crystal. But in the case of NFP,. Figure 7. IR absorption spectra of some alkali phosphate glasses. The compositions are NP53 = 5Na2O-3P2O5, NP = NaPO3, NLP = 4Na2O-1Li2O-3P2O5, NCP = 4Na2O-. 1CuO-3P2O5, NKP ...

  9. RAMAN SCATTERING BY MOLECULAR HYDROGEN AND NITROGEN IN EXOPLANETARY ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Oklopčić, Antonija [California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, California 91125 (United States); Hirata, Christopher M. [Center for Cosmology and Astroparticle Physics, Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio 43210 (United States); Heng, Kevin, E-mail: oklopcic@astro.caltech.edu [Center for Space and Habitability, University of Bern, Sidlerstrasse 5, CH-3012, Bern (Switzerland)

    2016-11-20

    An important source of opacity in exoplanet atmospheres at short visible and near-UV wavelengths is Rayleigh scattering of light on molecules. It is accompanied by a related, albeit weaker process—Raman scattering. We analyze the signatures of Raman scattering imprinted in the reflected light and the geometric albedo of exoplanets, which could provide information about atmospheric properties. Raman scattering affects the geometric albedo spectra of planets in the following ways. First, it causes filling-in of strong absorption lines in the incident radiation, thus producing sharp peaks in the albedo. Second, it shifts the wavelengths of spectral features in the reflected light causing the so-called Raman ghost lines. Raman scattering can also cause a broadband reduction of the albedo due to wavelength shifting of a stellar spectrum with red spectral index. Observing the Raman peaks in the albedo could be used to measure the column density of gas, thus providing constraints on the presence of clouds in the atmosphere. Observing the Raman ghost lines could be used to spectroscopically identify the main scatterer in the atmosphere, even molecules like H{sub 2} or N{sub 2}, which do not have prominent spectral signatures in the optical wavelength range. If detected, ghost lines could also provide information about the temperature of the atmosphere. In this paper, we investigate the effects of Raman scattering in hydrogen- and nitrogen-dominated atmospheres. We analyze the feasibility of detecting the signatures of Raman scattering with the existing and future observational facilities, and of using these signatures as probes of exoplanetary atmospheres.

  10. A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement

    DEFF Research Database (Denmark)

    Lenz, Robin; Enders, Kristina; Stedmon, Colin

    2015-01-01

    (n = 1279) were spectroscopically confirmed being plastic. The percentage varied with type, colour and size of the MP. Fibres had a higher success rate (75%) than particles (64%).We tested Raman micro-spectroscopy applicability for MP identification with respect to varying chemical composition...... (additives), degradation state and organic matter coating. Partially UV-degraded postconsumer plastics provided identifiable Raman spectra for polymers most common among marine MP, i.e. polyethylene and polypropylene...

  11. Raman spectroscopy for skin cancer diagnosis and characterisation of thin supported lipid films

    OpenAIRE

    Larraona-Puy, Marta

    2012-01-01

    Raman spectroscopy is a powerful tool in oncological imaging. Optical biopsies in which an accurate diagnosis of the tumour areas is spectroscopically performed are especially interesting for application to skin cancer treatments. In the first part of this dissertation a study on automated Raman spectral imaging allowed accurate diagnosis and delineation of the borders of a common type of skin cancer, basal cell carcinoma (BCC). Automated detection and imaging of BCC in skin sections exci...

  12. Application of spectroscopic methods in mineralogical and gemmological research of gem tourmalines

    OpenAIRE

    Peter Bačík; Jana Fridrichová; Ján Štubňa; Peter Antal

    2015-01-01

    Faceted tourmaline gemstones obtained from commercial sources as elbaites were studied with non-destructive spectroscopic methods. We applied Raman spectroscopy for mineral identification and UV/Vis/NIR spectroscopy for determination of chromophores. We identified the most of samples as fluor-elbaite to elbaite by Raman spectroscopy except one sample which has likely fluor-dravitic to fluor-uvitic composition. In green elbaitic tourmalines divalent iron is the most significant chromophore. Ye...

  13. Spectroscopic properties for identifying sapphire samples from Ban Bo Kaew, Phrae Province, Thailand

    Science.gov (United States)

    Mogmued, J.; Monarumit, N.; Won-in, K.; Satitkune, S.

    2017-09-01

    Gemstone commercial is a high revenue for Thailand especially ruby and sapphire. Moreover, Phrae is a potential gem field located in the northern part of Thailand. The studies of spectroscopic properties are mainly to identify gemstone using advanced techniques (e.g. UV-Vis-NIR spectrophotometry, FTIR spectrometry and Raman spectroscopy). Typically, UV-Vis-NIR spectrophotometry is a technique to study the cause of color in gemstones. FTIR spectrometry is a technique to study the functional groups in gem-materials. Raman pattern can be applied to identify the mineral inclusions in gemstones. In this study, the natural sapphires from Ban Bo Kaew were divided into two groups based on colors including blue and green. The samples were analyzed by UV-Vis-NIR spectrophotometer, FTIR spectrometer and Raman spectroscope for studying spectroscopic properties. According to UV-Vis-NIR spectra, the blue sapphires show higher Fe3+/Ti4+ and Fe2+/Fe3+ absorption peaks than those of green sapphires. Otherwise, green sapphires display higher Fe3+/Fe3+ absorption peaks than blue sapphires. The FTIR spectra of both blue and green sapphire samples show the absorption peaks of -OH,-CH and CO2. The mineral inclusions such as ferrocolumbite and rutile in sapphires from this area were observed by Raman spectroscope. The spectroscopic properties of sapphire samples from Ban Bo Kaew, Phrae Province, Thailand are applied to be the specific evidence for gemstone identification.

  14. Spectroscopic classification of transients

    DEFF Research Database (Denmark)

    Stritzinger, M. D.; Fraser, M.; Hummelmose, N. N.

    2017-01-01

    We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017.......We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017....

  15. Spectroscopic analysis and control

    Energy Technology Data Exchange (ETDEWEB)

    Tate; , James D.; Reed, Christopher J.; Domke, Christopher H.; Le, Linh; Seasholtz, Mary Beth; Weber, Andy; Lipp, Charles

    2017-04-18

    Apparatus for spectroscopic analysis which includes a tunable diode laser spectrometer having a digital output signal and a digital computer for receiving the digital output signal from the spectrometer, the digital computer programmed to process the digital output signal using a multivariate regression algorithm. In addition, a spectroscopic method of analysis using such apparatus. Finally, a method for controlling an ethylene cracker hydrogenator.

  16. Potential of Raman and Infrared Spectroscopy for Plant Analysis

    Science.gov (United States)

    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.

  17. Confocal Raman microscopy

    CERN Document Server

    Dieing, Thomas; Hollricher, Olaf

    2018-01-01

    This second edition provides a cutting-edge overview of physical, technical and scientific aspects related to the widely used analytical method of confocal Raman microscopy. The book includes expanded background information and adds insights into how confocal Raman microscopy, especially 3D Raman imaging, can be integrated with other methods to produce a variety of correlative microscopy combinations. The benefits are then demonstrated and supported by numerous examples from the fields of materials science, 2D materials, the life sciences, pharmaceutical research and development, as well as the geosciences.

  18. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    Science.gov (United States)

    Bagnall, Kevin R.; Wang, Evelyn N.

    2016-06-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E2 high and A1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse

  19. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bagnall, Kevin R.; Wang, Evelyn N. [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-06-15

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E{sub 2} high and A{sub 1} (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the

  20. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    International Nuclear Information System (INIS)

    Bagnall, Kevin R.; Wang, Evelyn N.

    2016-01-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E 2 high and A 1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse

  1. New imaging-based biomarkers for melanoma diagnosis using coherent Raman Scattering microscopy (Conference Presentation)

    Science.gov (United States)

    Wang, Hequn; Osseiran, Sam; Roider, Elisabeth; Fisher, David E.; Evans, Conor L.

    2016-02-01

    Recently, pheomelanin has been found to play a critical role in melanoma progression given its pro-oxidant chemical properties as well as its marked presence in pre-cancerous and malignant melanoma lesions, even in the absence of ultraviolet radiation. In addition, epidemiological evidence indicates a strong correlation between melanoma incidence and skin type, with the highest incidence occurring in individuals of the red-haired/fair-skinned phenotype. Interestingly, nevus count correlates well with melanoma incidence and skin type, except in the population most prone to developing melanoma, where nevus count strikingly drops. As such, a current hypothesis proposes that fair-skinned red-haired individuals, who are unable to stimulate production of eumelanin due to a mutation in MC1R in melanocytes, may actually harbor numerous "invisible", pheomelanin-rich nevi that evade clinical detection, supporting the high incidence of melanoma in that population. Here, we show for the very first time that melanocytes extracted from genetically modified MC1R-mutant, red-haired mice displayed bright perinuclear distributions of signal within the cells under coherent anti-Stokes Raman scattering (CARS) microscopy. Changes in pheomelanin production in siRNA knockdowns of cultured human melanoma cells were also sensed. We then successfully imaged pheomelanin distributions in both ex vivo and in vivo mouse ear skin. Finally, melanosomes within amelanotic melanoma patient tissue sections were found to show bright pheomelanin signals. This is the first time, to our knowledge, that pheomelanin has been found spatially localized in a human amelanotic melanoma sample. These pheomelanotic CARS features may be used as potential biomarkers for melanoma detection, especially for amelanotic melanomas.

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

    Science.gov (United States)

    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.

  3. Nanodiamonds and silicate minerals in ordinary chondrites as determined by micro-Raman spectroscopy

    Science.gov (United States)

    Saikia, Bhaskar J.; Parthasarathy, Gopalakrishnarao; Borah, Rashmi R.

    2017-06-01

    We present here the Raman spectroscopic study of silicate and carbonaceous minerals in three ordinary chondrites with the aim to improve our understanding the impact process including the peak metamorphic pressures present in carbon-bearing ordinary chondites. The characteristic Raman vibrational peaks of olivines, pyroxenes, and plagioclase have been determined on three ordinary chondrites from India, Dergaon (H5), Mahadevpur (H4/5), and Kamargaon (L6). The Raman spectra of these meteorite samples show the presence of nanodiamonds at 1334-1345 cm-1 and 1591-1619 cm-1. The full-width at half maximum (FWHM) of Raman peaks for Mahadevpur and Dergaon reflect the nature of shock metamorphism in these meteorites. The frequency shift in Raman spectra might be because of shock effects during the formation of the diamond/graphite grains.

  4. Spectroscopic properties of new luminescent system based on vanadate(V) crystal doped with erbium ions

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk, Marcin, E-mail: marcin@wchuwr.p [Faculty of Chemistry, University of Wroclaw, ul. F. Joliot-Curie 14, 50-383 Wroclaw (Poland); Lisiecki, RadosLaw; Solarz, Piotr; Ryba-Romanowski, Witold [Institute of Low Temperature and Structure Research Polish Academy of Sciences, ul. Okolna 2, 50-422 Wroclaw (Poland)

    2010-04-15

    Er{sup 3+}-doped KCaY(VO{sub 4}){sub 2} microcrystalline samples were synthesized using a high temperature solid-state reaction technique. Spectroscopic properties of Er{sup 3+}: KCaY(VO{sub 4}){sub 2} are studied and the nature of emissions is discussed. A strong green and infrared luminescence were observed under excitation at 314 nm in the O{sup 2-}->V{sup 5+} charge-transfer transitions and direct excitation of Er{sup 3+} ions at 435 nm. A strong emission lines in the blue region are due to the transitions of VO{sub 4}{sup 3-} ions have been observed at 77 K. The Judd-Ofelt parametrization scheme has been applied to the analysis of the room temperature absorption spectra in order to evaluate the intensity parameters, the branching ratios and the radiative lifetimes of the {sup 4}I{sub 13/2}, {sup 4}I{sub 11/2}, {sup 4}F{sub 9/2} and {sup 4}S{sub 3/2} emitting levels. The effective cross-section has been calculated for the {sup 4}I{sub 13/2}->{sup 4}I{sub 15/2} transition, indicating that the title compounds is a promising active medium for application in the three-level laser system. The up-conversion emission in Er{sup 3+}: KCaY(VO{sub 4}){sub 2} was investigated at 300 K. The decay profiles of the Stokes and anti-Stokes emissions were measured and the mechanism of up-conversion luminescence is discussed.

  5. Raman spectroscopy and oral exfoliative cytology

    Science.gov (United States)

    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.

  6. Spectroscopic Dosimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Analysis of Phase I test data demonstrates that the Photogenics Spectroscopic Dosimeter will detect neutron energies from 0.8 up to 600 MeV. The detector...

  7. Communication: atomic force detection of single-molecule nonlinear optical vibrational spectroscopy.

    Science.gov (United States)

    Saurabh, Prasoon; Mukamel, Shaul

    2014-04-28

    Atomic Force Microscopy (AFM) allows for a highly sensitive detection of spectroscopic signals. This has been first demonstrated for NMR of a single molecule and recently extended to stimulated Raman in the optical regime. We theoretically investigate the use of optical forces to detect time and frequency domain nonlinear optical signals. We show that, with proper phase matching, the AFM-detected signals closely resemble coherent heterodyne-detected signals. Applications are made to AFM-detected and heterodyne-detected vibrational resonances in Coherent Anti-Stokes Raman Spectroscopy (χ((3))) and sum or difference frequency generation (χ((2))).

  8. Propagation of a strong x-ray pulse: Pulse compression, stimulated Raman scattering, amplified spontaneous emission, lasing without inversion, and four-wave mixing

    International Nuclear Information System (INIS)

    Sun Yuping; Wang Chuankui; Liu Jicai; Gel'mukhanov, Faris

    2010-01-01

    We study the compression of strong x-ray pulses from x-ray free-electron lasers (XFELs) propagating through the resonant medium of atomic argon. The simulations are based on the three-level model with the frequency of the incident x-ray pulse tuned in the 2p 3/2 -4s resonance. The pulse propagation is accompanied by the self-seeded stimulated resonant Raman scattering (SRRS). The SRRS starts from two channels of amplified spontaneous emission (ASE), 4s-2p 3/2 and 3s-2p 3/2 , which form the extensive ringing pattern and widen the power spectrum. The produced seed field triggers the Stokes ASE channel 3s-2p 3/2 . The population inversion is quenched for longer propagation distances where the ASE is followed by the lasing without inversion (LWI), which amplifies the Stokes component. Both ASE and LWI reshape the input pulse: The compressed front part of the pulse (up to 100 as) is followed by the long tail of the ringing and beating between the pump and Stokes frequencies. The pump pulse also generates weaker Stokes and anti-Stokes fields caused by four-wave mixing. These four spectral bands have fine structures caused by the dynamical Stark effect. A slowdown of the XFEL pulse up to 78% of the speed of light in vacuum is found because of a large nonlinear refractive index.

  9. Combined raman/laser-induced breakdown spectrometer: space and non-space applications

    NARCIS (Netherlands)

    Sandtke, M.; Laan, E.C.; Ahlers, B.

    2010-01-01

    TNO has developed the combination of two spectroscopic analysis methods in one instrument. Raman spectroscopy and Laser-induced Breakdown Spectroscopy (LIBS) were brought together for an instrument to be flown on the ExoMars mission from the European Space Agency (ESA) to investigate the Martian

  10. Nanoparticle detection in aqueous solutions using Raman and Laser Induced Breakdown Spectroscopy

    NARCIS (Netherlands)

    Sovago, M.; Buis, E.-J.; Sandtke, M.

    2013-01-01

    We show the chemical identification and quantification of the concentration and size of nanoparticle (NP) dispersions in aqueous solutions by using a combination of Raman Spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). The two spectroscopic techniques are applied to demonstrate the NP

  11. Raman study on single-walled carbon nanotubes with different laser ...

    Indian Academy of Sciences (India)

    TECS

    identify the nature of carbon nanotubes in a bundle. In this study, we have used the Raman spectroscopic analysis on vertically aligned single-walled carbon nanotubes (SWCNTs) grown by the chemical vapour depo- sition (CVD) technique. The grown sample is excited with two laser excitation wavelengths, 633 nm from ...

  12. On the Increasing Fragility of Human Teeth with Age: ADeep-Ultraviolet Resonance Raman Study

    Energy Technology Data Exchange (ETDEWEB)

    Ager III, J.W.; Nalla, R.K.; Balooch, G.; Kim, G.; Pugach, M.; Habelitz, S.; Marshall, G.W.; Kinney, J.H.; Ritchie, R.O.

    2006-07-14

    Ultraviolet resonance Raman spectroscopy (UVRRS) using 244nm excitation was used to investigate the impact of aging on humandentin. The intensity of a spectroscopic feature from the peptide bondsin the collagen increases with tissue age, similar to a finding reportedpreviously for human cortical bone.

  13. Raman study on single-walled carbon nanotubes with different laser ...

    Indian Academy of Sciences (India)

    TECS

    Abstract. The industrial use of carbon nanotubes is increasing day by day; therefore, it is very important to identify the nature of carbon nanotubes in a bundle. In this study, we have used the Raman spectroscopic analysis on vertically aligned single-walled carbon nanotubes (SWCNTs) grown by the chemical vapour depo-.

  14. Spectroscopic sensors for in-line bioprocess monitoring in research and pharmaceutical industrial application.

    Science.gov (United States)

    Claßen, Jens; Aupert, Florian; Reardon, Kenneth F; Solle, Dörte; Scheper, Thomas

    2017-01-01

    The use of spectroscopic sensors for bioprocess monitoring is a powerful tool within the process analytical technology (PAT) initiative of the US Food and Drug Administration. Spectroscopic sensors enable the simultaneous real-time bioprocess monitoring of various critical process parameters including biological, chemical, and physical variables during the entire biotechnological production process. This potential can be realized through the combination of spectroscopic measurements (UV/Vis spectroscopy, IR spectroscopy, fluorescence spectroscopy, and Raman spectroscopy) with multivariate data analysis to obtain relevant process information out of an enormous amount of data. This review summarizes the newest results from science and industry after the establishment of the PAT initiative and gives a critical overview of the most common in-line spectroscopic techniques. Examples are provided of the wide range of possible applications in upstream processing and downstream processing of spectroscopic sensors for real-time monitoring to optimize productivity and ensure product quality in the pharmaceutical industry.

  15. Raman fiberoptic probe for monitoring human tissue engineered oral mucosa constructs

    Science.gov (United States)

    Khmaladze, Alexander; Kuo, Shiuhyang; Okagbare, Paul; Marcelo, Cynthia L.; Feinberg, Stephen E.; Morris, Michael D.

    2013-02-01

    In oral and maxillofacial surgery, there is a need for tissue engineered constructs for dental implants, reconstructions due to trauma, oral cancer or congenital defects. A non-invasive quality monitoring of the fabrication of tissue engineered constructs during their production and implantation is a required component of any successful tissue engineering technique. We demonstrate the design and application of a Raman spectroscopic probe for rapid and noninvasive monitoring of Ex Vivo Produced Oral Mucosa Equivalent constructs (EVPOMEs). We conducted in vivo studies to identify Raman spectroscopic failure indicators for EVPOMEs (already developed in vitro), and found that Raman spectra of EVPOMEs exposed to thermal stress showed correlation of the band height ratio of CH2 deformation to phenylalanine ring breathing modes, providing a Raman metric to distinguish between viable and nonviable constructs. This is the first step towards the ultimate goal to design a stand-alone system, which will be usable in a clinical setting, as the data processing and analysis will be performed with minimal user intervention, based on already established and tested Raman spectroscopic indicators for EVPOMEs.

  16. Spectroscopic studies of anthracyclines: Structural characterization and in vitro tracking.

    Science.gov (United States)

    Szafraniec, Ewelina; Majzner, Katarzyna; Farhane, Zeineb; Byrne, Hugh J; Lukawska, Malgorzata; Oszczapowicz, Irena; Chlopicki, Stefan; Baranska, Malgorzata

    2016-12-05

    A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488nm and 785nm as source wavelengths, with submicrometer spatial resolution, although the cellular accumulation of the drug is different in each case. The high information content of Raman spectra allows studies of the drug-cell interactions, and so the method seems very suitable for monitoring drug uptake and mechanisms of interaction with cellular compartments at the subcellular level. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Surface-Enhanced Raman Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Surface-Enhanced Raman Spectroscopy - Recent Advancement of Raman Spectroscopy. Ujjal Kumar Sur. General Article Volume 15 Issue 2 February 2010 pp 154-164 ...

  18. Development of Raman spectrophotometer

    International Nuclear Information System (INIS)

    Adam, A.I.

    2008-05-01

    In this work, the Raman spectrophotometer HG.2S Jobin Yvon rebuilt and developed, the Raman setup provided as a gift for Neelian University from Amsterdam University. The main parts, which were replaced, include monochromator, an air-cooled photomultiplier tube RCA IP 28, log amplifier, hand scanning lab VIEW card for computer interfacing. The components assembled and the whole device was tested successfully. The developed setup was checked using some standard solutions, which showed perfect consistency with literature in the references and published papers. Solutions included hexane, cyclohexane, carbon tetrachloride, benzene and sodium sulfate.(Author)

  19. Transcutaneous Raman spectroscopy of murine bone in vivo.

    Science.gov (United States)

    Schulmerich, Matthew V; Cole, Jacqueline H; Kreider, Jaclynn M; Esmonde-White, Francis; Dooley, Kathryn A; Goldstein, Steven A; Morris, Michael D

    2009-03-01

    Raman spectroscopy can provide valuable information about bone tissue composition in studies of bone development, biomechanics, and health. In order to study the Raman spectra of bone in vivo, instrumentation that enhances the recovery of subsurface spectra must be developed and validated. Five fiber-optic probe configurations were considered for transcutaneous bone Raman spectroscopy of small animals. Measurements were obtained from the tibia of sacrificed mice, and the bone Raman signal was recovered for each probe configuration. The configuration with the optimal combination of bone signal intensity, signal variance, and power distribution was then evaluated under in vivo conditions. Multiple in vivo transcutaneous measurements were obtained from the left tibia of 32 anesthetized mice. After collecting the transcutaneous Raman signal, exposed bone measurements were collected and used as a validation reference. Multivariate analysis was used to recover bone spectra from transcutaneous measurements. To assess the validity of the transcutaneous bone measurements cross-correlations were calculated between standardized spectra from the recovered bone signal and the exposed bone measurements. Additionally, the carbonate-to-phosphate height ratios of the recovered bone signals were compared to the reference exposed bone measurements. The mean cross-correlation coefficient between the recovered and exposed measurements was 0.96, and the carbonate-to-phosphate ratios did not differ significantly between the two sets of spectra (p > 0.05). During these first systematic in vivo Raman measurements, we discovered that probe alignment and animal coat color influenced the results and thus should be considered in future probe and study designs. Nevertheless, our noninvasive Raman spectroscopic probe accurately assessed bone tissue composition through the skin in live mice.

  20. Surface-Enhanced Raman Scattering Using Silica Whispering-Gallery Mode Resonators

    Science.gov (United States)

    Anderson, Mark S.

    2013-01-01

    The motivation of this work was to have robust spectroscopic sensors for sensitive detection and chemical analysis of organic and molecular compounds. The solution is to use silica sphere optical resonators to provide surface-enhanced spectroscopic signal. Whispering-gallery mode (WGM) resonators made from silica microspheres were used for surface-enhanced Raman scattering (SERS) without coupling to a plasmonic mechanism. Large Raman signal enhancement is observed by exclusively using 5.08-micron silica spheres with 785-nm laser excitation. The advantage of this non-plasmonic approach is that the active substrate is chemically inert silica, thermally stable, and relatively simple to fabricate. The Raman signal enhancement is broadly applicable to a wide range of molecular functional groups including aliphatic hydrocarbons, siloxanes, and esters. Applications include trace organic analysis, particularly for in situ planetary instruments that require robust sensors with consistent response.