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Sample records for matrix fluorescence spectroscopy

  1. Light emitting diode excitation emission matrix fluorescence spectroscopy.

    Science.gov (United States)

    Hart, Sean J; JiJi, Renée D

    2002-12-01

    An excitation emission matrix (EEM) fluorescence instrument has been developed using a linear array of light emitting diodes (LED). The wavelengths covered extend from the upper UV through the visible spectrum: 370-640 nm. Using an LED array to excite fluorescence emission at multiple excitation wavelengths is a low-cost alternative to an expensive high power lamp and imaging spectrograph. The LED-EEM system is a departure from other EEM spectroscopy systems in that LEDs often have broad excitation ranges which may overlap with neighboring channels. The LED array can be considered a hybrid between a spectroscopic and sensor system, as the broad LED excitation range produces a partially selective optical measurement. The instrument has been tested and characterized using fluorescent dyes: limits of detection (LOD) for 9,10-bis(phenylethynyl)-anthracene and rhodamine B were in the mid parts-per-trillion range; detection limits for the other compounds were in the low parts-per-billion range (LED-EEMs were analyzed using parallel factor analysis (PARAFAC), which allowed the mathematical resolution of the individual contributions of the mono- and dianion fluorescein tautomers a priori. Correct identification and quantitation of six fluorescent dyes in two to six component mixtures (concentrations between 12.5 and 500 ppb) has been achieved with root mean squared errors of prediction (RMSEP) of less than 4.0 ppb for all components.

  2. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  3. Fluorescence excitation-emission matrix spectroscopy for degradation monitoring of machinery lubricants

    Science.gov (United States)

    Sosnovski, Oleg; Suresh, Pooja; Dudelzak, Alexander E.; Green, Benjamin

    2018-02-01

    Lubrication oil is a vital component of heavy rotating machinery defining the machine's health, operational safety and effectiveness. Recently, the focus has been on developing sensors that provide real-time/online monitoring of oil condition/lubricity. Industrial practices and standards for assessing oil condition involve various analytical methods. Most these techniques are unsuitable for online applications. The paper presents the results of studying degradation of antioxidant additives in machinery lubricants using Fluorescence Excitation-Emission Matrix (EEM) Spectroscopy and Machine Learning techniques. EEM Spectroscopy is capable of rapid and even standoff sensing; it is potentially applicable to real-time online monitoring.

  4. Fluorescence excitation-emission matrix spectroscopy of vitiligo skin in vivo (Conference Presentation)

    Science.gov (United States)

    Zhao, Jianhua; Richer, Vincent; Al Jasser, Mohammed; Zandi, Soodabeh; Kollias, Nikiforos; Kalia, Sunil; Zeng, Haishan; Lui, Harvey

    2016-02-01

    Fluorescence signals depend on the intensity of the exciting light, the absorption properties of the constituent molecules, and the efficiency with which the absorbed photons are converted to fluorescence emission. The optical features and appearance of vitiligo have been explained primarily on the basis of reduced epidermal pigmentation, which results in abnormal white patches on the skin. The objective of this study is to explore the fluorescence properties of vitiligo and its adjacent normal skin using fluorescence excitation-emission matrix (EEM) spectroscopy. Thirty five (35) volunteers with vitiligo were acquired using a double-grating spectrofluorometer with excitation and emission wavelengths of 260-450 nm and 300-700 nm respectively. As expected, the most pronounced difference between the spectra obtained from vitiligo lesions compared to normally pigmented skin was that the overall fluorescence was much higher in vitiligo; these differences increased at shorter wavelengths, thus matching the characteristic spectral absorption of epidermal melanin. When comparing the fluorescence spectra from vitiligo to normal skin we detected three distinct spectral bands centered at 280nm, 310nm, and 335nm. The 280nm band may possibly be related to inflammation, whereas the 335 nm band may arise from collagen or keratin cross links. The source of the 310 nm band is uncertain; it is interesting to note its proximity to the 311 nm UV lamps used for vitiligo phototherapy. These differences are accounted for not only by changes in epidermal pigment content, but also by other optically active cutaneous biomolecules.

  5. Characterization of dissolved organic matter in fogwater by excitation-emission matrix fluorescence spectroscopy

    Science.gov (United States)

    Birdwell, J.E.; Valsaraj, K.T.

    2010-01-01

    Dissolved organic matter (DOM) present in fogwater samples collected in southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix fluorescence spectroscopy. The goal of the study was to illustrate the utility of fluorescence for obtaining information on the large fraction of organic carbon in fogwaters (typically >40% by weight) that defies characterization in terms of specific chemical compounds without the difficulty inherent in obtaining sufficient fogwater volume to isolate DOM for assessment using other spectroscopic and chemical analyses. Based on the findings of previous studies using other characterization methods, it was anticipated that the unidentified organic carbon fraction would have characteristic peaks associated with humic substances and fluorescent amino acids. Both humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices for the fogwater had similar values to those of soil and sediment porewater. Greater biological character was observed in samples with higher organic carbon concentrations. Fogwaters are shown to contain a mixture of terrestrially- and microbially-derived fluorescent organic material, which is expected to be derived from an array of different sources, such as suspended soil and dust particles, biogenic emissions and organic substances generated by atmospheric processes. The fluorescence results indicate that much of the unidentified organic carbon present in fogwater can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems, though it should be noted that fluorescent signatures representative of DOM produced by atmospheric processing of organic aerosols may be contributing to or masked by humic-like fluorophores. ?? 2010.

  6. [Fluorescence excitation-emission matrix spectroscopy of CDOM from Yundang Lagoon and its indication for organic pollution].

    Science.gov (United States)

    Zhuo, Jian-Fu; Guo, Wei-Dong; Deng, Xun; Zhang, Zhi-Ying; Xu, Jing; Huang, Ling-Feng

    2010-06-01

    Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with absorption spectroscopy were applied to study the optical properties of CDOM samples from highly-polluted Yundang Lagoon in Xiamen in order to demonstrate the feasibility of using these spectral properties as a tracer of the degree of organic pollution in similar polluted coastal waters. Surface water samples were collected from 13 stations 4 times during April and May, 2008. Parallel factor analysis (PARAFAC) model was used to resolve the EEMs of CDOM. Five separate fluorescent components were identified, including two humic-like components (C1: 240, 325/422 nm; C5: 260, 380/474 nm), two protein-like components (C2: 225, 275/350 nm; C4: 240, 300/354 nm) and one xenobiotic-like component (C3: 225/342 nm), which could be used as a good tracer for the input of the anthropogenic organic, pollutants. The concentrations of component C3 and dissolved organic carbon (DOC) are much higher near the inlet of sewage discharge, demonstrating that the discharge of surrounding sewage is a major source of organic pollutants in Yundang Lagoon. CDOM absorption coefficient alpha (280) and the score of humic-like component C1 showed significant linear relationships with COD(Mn), and a strong positive correlation was also found between the score of protein-like component C2 and BOD5. This suggested that the optical properties of CDOM may provide a fast in-situ way to monitor the variation of the water quality in Yundang Lagoon and that of similar polluted coastal waters.

  7. Fluorescence excitation-emission matrix (EEM) spectroscopy for rapid identification and quality evaluation of cell culture media components.

    Science.gov (United States)

    Li, Boyan; Ryan, Paul W; Shanahan, Michael; Leister, Kirk J; Ryder, Alan G

    2011-11-01

    The application of fluorescence excitation-emission matrix (EEM) spectroscopy to the quantitative analysis of complex, aqueous solutions of cell culture media components was investigated. These components, yeastolate, phytone, recombinant human insulin, eRDF basal medium, and four different chemically defined (CD) media, are used for the formulation of basal and feed media employed in the production of recombinant proteins using a Chinese Hamster Ovary (CHO) cell based process. The comprehensive analysis (either identification or quality assessment) of these materials using chromatographic methods is time consuming and expensive and is not suitable for high-throughput quality control. The use of EEM in conjunction with multiway chemometric methods provided a rapid, nondestructive analytical method suitable for the screening of large numbers of samples. Here we used multiway robust principal component analysis (MROBPCA) in conjunction with n-way partial least squares discriminant analysis (NPLS-DA) to develop a robust routine for both the identification and quality evaluation of these important cell culture materials. These methods are applicable to a wide range of complex mixtures because they do not rely on any predetermined compositional or property information, thus making them potentially very useful for sample handling, tracking, and quality assessment in biopharmaceutical industries.

  8. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs

  9. Fluorescence fluctuation spectroscopy (FFS)

    CERN Document Server

    Tetin, Sergey

    2012-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial with quality chapters authored by leaders in the field. This volume covers fluorescence fluctuation spectroscopy and includes chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells. Continues the legacy of this premier serial with quality chapters authored by leaders in the field Covers fluorescence fluctuation spectroscopy Contains chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells.

  10. [Study on optical characteristics of chromophoric dissolved organic matter (CDOM) in rainwater by fluorescence excitation-emission matrix and absorbance spectroscopy].

    Science.gov (United States)

    Cheng, Yuan-yue; Guo, Wei-dong; Long, Ai-min; Chen, Shao-yong

    2010-09-01

    The optical characteristics of chromophoric dissolved organic matter (CDOM) were determined in rain samples collected in Xiamen Island, during a rainy season in 2007, using fluorescence excitation-emission matrix spectroscopy associated with UV-Vis absorbance spectra. Results showed that the absorbance spectra of CDOM in rain samples decreased exponentially with wavelength. The absorbance coefficient at 300 nm [a(300)] ranged from 0.27 to 3.45 m(-1), which would be used as an index of CDOM abundance, and the mean value was 1.08 m(-1). The content of earlier stage of precipitation events was higher than that of later stage of precipitation events, which implied that anthropogenic sources or atmospheric pollution or air mass types were important contributors to CDOM levels in precipitation. EEMs spectra showed 4 types of fluorescence signals (2 humic-like fluorescence peaks and 2 protein-like fluorescence peaks) in rainwater samples, and there were significant positive correlations of peak A with C and peak B with S, showing their same sources or some relationship of the two humic-like substance and the two protein-like substance. The strong positive correlations of the two humic-like fluorescence peaks with a(300), suggested that the chromophores responsible for absorbance might be the same as fluorophores responsible for fluorescence. Results showed that the presence of highly absorbing and fluorescing CDOM in rainwater is of significant importance in atmospheric chemistry and might play a previously unrecognized role in the wavelength dependent spectral attenuation of solar radiation by atmospheric waters.

  11. Characteristics of the fluorescent substances in the Yodo River system by three-dimensional excitation emission matrix spectroscopy; Sanjigen reiki/keiko kodoho ni yoru yodogawa suikeichu no keiko busshitsu no tokucho

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y.; Nakaguchi, Y.; Hiraki, K.; Kudo, M.; Kimura, M.; Nagao, S. [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1998-08-01

    Organic substances in the river water in Yodo River system were analyzed by three-dimensional excitation emission matrix spectroscopy. Fluorescent substances were taken as an index of organic substances. The amount of fluorescent substances varied widely depending on the environment of river basin. It is suggested that the fluorescent substances are composed of organic substances which is not directly originated from biological activity. It is suggested that the fluorescent substances were produced by leaching of river bottom sediment. The fluorescent substances in Yodo River system consists of fulvic acid-like substances and protein. The analysis of fluorescent substances in river water by three-dimensional excitation emission matrix spectroscopy can be useful means for estimation of variation and origin of fluorescent substances. For better understanding of features of fluorescent substances in the surface water into which various kinds of substances enter, it is necessary to determine the exact sampling points based on the consideration of different sources and to make a database of peak positions for identification of fluorescent substances from fluorescence intensity peak. 29 refs., 3 figs., 2 tabs.

  12. Fluorescence excitation-emission matrix (EEM) spectroscopy and cavity ring-down (CRD) absorption spectroscopy of oil-contaminated jet fuel using fiber-optic probes.

    Science.gov (United States)

    Omrani, Hengameh; Barnes, Jack A; Dudelzak, Alexander E; Loock, Hans-Peter; Waechter, Helen

    2012-06-21

    Excitation emission matrix (EEM) and cavity ring-down (CRD) spectral signatures have been used to detect and quantitatively assess contamination of jet fuels with aero-turbine lubricating oil. The EEM spectrometer has been fiber-coupled to permit in situ measurements of jet turbine oil contamination of jet fuel. Parallel Factor (PARAFAC) analysis as well as Principal Component Analysis and Regression (PCA/PCR) were used to quantify oil contamination in a range from the limit of detection (10 ppm) to 1000 ppm. Fiber-loop cavity ring-down spectroscopy using a pulsed 355 nm laser was used to quantify the oil contamination in the range of 400 ppm to 100,000 ppm. Both methods in combination therefore permit the detection of oil contamination with a linear dynamic range of about 10,000.

  13. Characterization of DOM adsorption of CNTs by using excitation-emission matrix fluorescence spectroscopy and multiway analysis.

    Science.gov (United States)

    Peng, Mingguo; Li, Huajie; Li, Dongdong; Du, Erdeng; Li, Zhihong

    2017-06-01

    Carbon nanotubes (CNTs) were utilized to adsorb DOM in micro-polluted water. The characteristics of DOM adsorption on CNTs were investigated based on UV 254 , TOC, and fluorescence spectrum measurements. Based on PARAFAC (parallel factor) analysis, four fluorescent components were extracted, including one protein-like component (C4) and three humic acid-like components (C1, C2, and C3). The adsorption isotherms, kinetics, and thermodynamics of DOM adsorption on CNTs were further investigated. A Freundlich isotherm model fit the adsorption data well with high values of correlation. As a type of macro-porous and meso-porous adsorbent, CNTs preferably adsorb humic acid-like substances rather than protein-like substances. The increasing temperature will speed up the adsorption process. The self-organizing map (SOM) analysis further explains the fluorescent properties of water samples. The results provide a new insight into the adsorption behaviour of DOM fluorescent components on CNTs.

  14. Multimodal fluorescence imaging spectroscopy

    NARCIS (Netherlands)

    Stopel, Martijn H W; Blum, Christian; Subramaniam, Vinod; Engelborghs, Yves; Visser, Anthonie J.W.G.

    2014-01-01

    Multimodal fluorescence imaging is a versatile method that has a wide application range from biological studies to materials science. Typical observables in multimodal fluorescence imaging are intensity, lifetime, excitation, and emission spectra which are recorded at chosen locations at the sample.

  15. Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Kapusta, Peter; Hof, Martin

    Roč. 406 , č. 20 (2014), s. 4797-4813 ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

  16. Fluorescence fluctuation spectroscopy (FFS), part A

    CERN Document Server

    Tetin, Sergey

    2013-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial by containing quality chapters authored by leaders in the field. This volume covers Fluorescence Fluctuation SpectroscopyContains chapters on such topics as Time-integrated fluorescence cumulant analysis, Pulsed Interleaved Excitation, and raster image correlation spectroscopy and number and brightness analysis.Continues the legacy of this premier serial with quality chapters authored by leaders in the fieldCovers fluorescence fluctuation spectroscopyContains chapte

  17. Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy with regional integration analysis for assessing waste sludge hydrolysis treated with multi-enzyme and thermophilic bacteria.

    Science.gov (United States)

    Guo, Liang; Lu, Mingmin; Li, Qianqian; Zhang, Jiawen; Zong, Yan; She, Zonglian

    2014-11-01

    The hydrolysis effect of waste sludge after multi-enzyme and thermophilic bacteria pretreatments is investigated using excitation-emission matrix (EEM) with fluorescence regional integration (FRI) in this study. The compositional characteristics of extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed to evaluate the sludge disintegration. The EPS and cell wall in sludge were disrupted after hydrolysis which led to carbohydrate, protein and soluble chemical oxygen demand (SCOD) of DOM increasing in sludge supernatant. The bio-degradability level in the extracted fractions of EPS and DOM depending on the fluorescence zones was found after hydrolysis. The highest proportion of percent fluorescence response (Pi,n) in EPS and DOM was soluble microbial by-product and humic acid-like organics. A significant increase of humic acid-like organics in DOM after thermophilic bacteria hydrolysis was obtained. The assessment of hydrolysis using EEM coupled with FRI provided a new insight toward the bio-utilization process of waste sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Force spectroscopy of hepatocytic extracellular matrix components

    Energy Technology Data Exchange (ETDEWEB)

    Yongsunthon, R., E-mail: YongsuntR@Corning.com [Corning Incorporated, SP-FR-01, R1S32D, Corning, NY 14831 (United States); Baker, W.A.; Bryhan, M.D.; Baker, D.E.; Chang, T.; Petzold, O.N.; Walczak, W.J.; Liu, J.; Faris, R.A.; Senaratne, W.; Seeley, L.A.; Youngman, R.E. [Corning Incorporated, SP-FR-01, R1S32D, Corning, NY 14831 (United States)

    2009-07-15

    We present atomic force microscopy and force spectroscopy data of live hepatocytes (HEPG2/C3A liver cell line) grown in Eagle's Minimum Essential Medium, a complex solution of salts and amino acids commonly used for cell culture. Contact-mode imaging and force spectroscopy of this system allowed correlation of cell morphology and extracellular matrix (ECM) properties with substrate properties. Force spectroscopy analysis of cellular 'footprints' indicated that the cells secrete large polymers (e.g., 3.5 {mu}m contour length and estimated MW 1000 kDa) onto their substrate surface. Although definitive identification of the polymers has not yet been achieved, fluorescent-labeled antibody staining has specified the presence of ECM proteins such as collagen and laminin in the cellular footprints. The stretched polymers appear to be much larger than single molecules of known ECM components, such as collagen and heparan sulfate proteoglycan, thus suggesting that the cells create larger entangled, macromolecular structures from smaller components. There is strong evidence which suggests that the composition of the ECM is greatly influenced by the hydrophobicity of the substrate surface, with preferential production and/or adsorption of larger macromolecules on hydrophobic surfaces.

  19. Fluorescence spectroscopy of dental calculus

    International Nuclear Information System (INIS)

    Bakhmutov, D; Gonchukov, S; Sukhinina, A

    2010-01-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined

  20. Fluorescence spectroscopy of dental calculus

    Science.gov (United States)

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

    2010-05-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined.

  1. Quantitative fluorescence spectroscopy in turbid media using fluorescence differential path length spectroscopy

    NARCIS (Netherlands)

    Amelink, Arjen; Kruijt, Bastiaan; Robinson, Dominic J.; Sterenborg, Henricus J. C. M.

    2008-01-01

    We have developed a new technique, fluorescence differential path length spectroscopy (FDPS), that enables the quantitative investigation of fluorophores in turbid media. FDPS measurements are made with the same probe geometry as differential path length spectroscopy (DPS) measurements. Phantom

  2. Time-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gustavsson, Thomas; Mialocq, Jean-Claude

    2007-01-01

    This article addresses the evolution in time of light emitted by a molecular system after a brief photo-excitation. The authors first describe fluorescence from a photo-physical point of view and discuss the characterization of the excited state. Then, they explain some basic notions related to fluorescence characterization (lifetime and decays, quantum efficiency, so on). They present the different experimental methods and techniques currently used to study time-resolved fluorescence. They discuss basic notions of time resolution and spectral reconstruction. They briefly present some conventional methods: intensified Ccd cameras, photo-multipliers and photodiodes associated with a fast oscilloscope, and phase modulation. Other methods and techniques are more precisely presented: time-correlated single photon counting (principle, examples, and fluorescence lifetime imagery), streak camera (principle, examples), and optical methods like the Kerr optical effect (principle and examples) and fluorescence up-conversion (principle and theoretical considerations, examples of application)

  3. Fluorescence spectroscopy for neoplasms control

    Science.gov (United States)

    Bratchenko, I. A.; Kristoforova, Yu. A.; Myakinin, O. O.; Artemyev, D. N.; Kozlov, S. V.; Moryatov, A. A.; Zakharov, V. P.

    2016-04-01

    Investigation of malignant skin tumors diagnosis was performed involving two setups for native tissues fluorescence control in visible and near infrared regions. Combined fluorescence analysis for skin malignant melanomas and basal cell carcinomas was performed. Autofluorescence spectra of normal skin and oncological pathologies stimulated by 457 nm and 785 nm lasers were registered for 74 skin tissue samples. Spectra of 10 melanomas and 27 basal cell carcinomas were registered ex vivo. Skin tumors analysis was made on the basis of autofluorescence spectra intensity and curvature for analysis of porphyrins, lipo-pigments, flavins and melanin. Separation of melanomas and basal cell carcinomas was performed on the basis of discriminant analysis. Overall accuracy of basal cell carcinomas and malignant melanomas separation in current study reached 86.5% with 70% sensitivity and 92.6% specificity.

  4. Xanthines Studied via Femtosecond Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    Pascale Changenet-Barret

    2016-12-01

    Full Text Available Xanthines represent a wide class of compounds closely related to the DNA bases adenine and guanine. Ubiquitous in the human body, they are capable of replacing natural bases in double helices and give rise to four-stranded structures. Although the use of their fluorescence for analytical purposes was proposed, their fluorescence properties have not been properly characterized so far. The present paper reports the first fluorescence study of xanthine solutions relying on femtosecond spectroscopy. Initially, we focus on 3-methylxanthine, showing that this compound exhibits non-exponential fluorescence decays with no significant dependence on the emission wavelength. The fluorescence quantum yield (3 × 10−4 and average decay time (0.9 ps are slightly larger than those found for the DNA bases. Subsequently, we compare the dynamical fluorescence properties of seven mono-, di- and tri-methylated derivatives. Both the fluorescence decays and fluorescence anisotropies vary only weakly with the site and the degree of methylation. These findings are in line with theoretical predictions suggesting the involvement of several conical intersections in the relaxation of the lowest singlet excited state.

  5. Fluorescence spectroscopy for medical and environmental diagnostics

    International Nuclear Information System (INIS)

    Johansson, Jonas.

    1993-09-01

    Fluorescence spectroscopy can be used for diagnostics in medical and environmental applications. The many aspects of fluorescence emission are utilized to enhance the accuracy of the diagnosis. A fluorescence detection system, based on nitrogen laser or dye laser excitation and optical multichannel detection, was constructed, and fluorescence spectra from human malignant tumours of various origins, were recorded. Tumour demarcation was observed using exogenous chromophores, as well as the endogenous tissue fluorescence. In particular, δ-amino levulinic acid was found to provide very good tumour demarcation. A multi-colour imaging system capable of simultaneous recording of four fluorescence images at selected wavelengths, was developed. Examples of processed images, based on the four sub-images, are shown for malignant tumours. In addition, data from photodynamic treatment of human malignant tumours are presented. Autofluorescence spectra from excised pieces of human atherosclerotic aorta and atherosclerotic coronary segment were found to be different from those of non-diseased vessels. Furthermore, fluorescence decay curves from atherosclerotic samples were found to differ from those of non-diseased samples. It is concluded that both spectral and temporal information should be utilized to enhance the demarcation. Methods for obtaining fluorescence data free from interference from blood, with applications to in vivo laser angioplasty of atherosclerosis, are discussed. The optical multichannel system and the multi-colour imaging system were integrated with a remote sensing system, originally used for environmental measurements, to obtain fluorescence spectra as well as fluorescence images of plants at a distance of up to 100 m. The fluorescence data from plants subject to environmental stress or senescent plants were found to differ from those obtained from healthy vegetation. 359 refs

  6. Total Internal Reflection Fluorescence Microscopy Imaging-Guided Confocal Single-Molecule Fluorescence Spectroscopy

    OpenAIRE

    Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter

    2013-01-01

    We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...

  7. Ultraviolet, Visible, and Fluorescence Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  8. Detecting Kerogen as a Biosignature Using Colocated UV Time-Gated Raman and Fluorescence Spectroscopy.

    Science.gov (United States)

    Shkolyar, Svetlana; Eshelman, Evan J; Farmer, Jack D; Hamilton, David; Daly, Michael G; Youngbull, Cody

    2018-04-01

    The Mars 2020 mission will analyze samples in situ and identify any that could have preserved biosignatures in ancient habitable environments for later return to Earth. Highest priority targeted samples include aqueously formed sedimentary lithologies. On Earth, such lithologies can contain fossil biosignatures as aromatic carbon (kerogen). In this study, we analyzed nonextracted kerogen in a diverse suite of natural, complex samples using colocated UV excitation (266 nm) time-gated (UV-TG) Raman and laser-induced fluorescence spectroscopies. We interrogated kerogen and its host matrix in samples to (1) explore the capabilities of UV-TG Raman and fluorescence spectroscopies for detecting kerogen in high-priority targets in the search for possible biosignatures on Mars; (2) assess the effectiveness of time gating and UV laser wavelength in reducing fluorescence in Raman spectra; and (3) identify sample-specific issues that could challenge rover-based identifications of kerogen using UV-TG Raman spectroscopy. We found that ungated UV Raman spectroscopy is suited to identify diagnostic kerogen Raman bands without interfering fluorescence and that UV fluorescence spectroscopy is suited to identify kerogen. These results highlight the value of combining colocated Raman and fluorescence spectroscopies, similar to those obtainable by SHERLOC on Mars 2020, to strengthen the confidence of kerogen detection as a potential biosignature in complex natural samples. Key Words: Raman spectroscopy-Laser-induced fluorescence spectroscopy-Mars Sample Return-Mars 2020 mission-Kerogen-Biosignatures. Astrobiology 18, 431-453.

  9. Uranium concentrate analysis by X-ray fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Diaz-Guerra, J.P.; Bayon, A.; Roca, R.

    1978-01-01

    The determination of As, Ca, Fe, Mo, P, S, Si. Th, V and U in uranium concentrates by X-ray fluorescence spectroscopy has been studied. As and U are determined in nitric solutions and for the rest of elements analysis is performed by a bead fusion technique using Li 2 B 4 O 7 and Li 2 CO 3 as fluxes. Although the uranium matrix minimizes the absorption and enhancement effects, because of the content variations of this element it is advisable to operate at a constant level of U 3 O 8 . Despite the high matrix absorption and the large dilution of the samples, sensitivity and speed are found to be satisfactory as the result of the use of a high sensitivity automatic spectrometer. The spectral interferences of Mo on S and P, and of Pb on As have been particularly considered. (author) [es

  10. Laser induced fluorescence spectroscopy for FTU

    International Nuclear Information System (INIS)

    Hughes, T.P.

    1995-07-01

    Laser induced fluorescence spectroscopy (LIFS) is based on the absorption of a short pulse of tuned laser light by a group of atoms and the observation of the resulting fluorescence radiation from the excited state. Because the excitation is resonant it is very efficient, and the fluorescence can be many times brighter than the normal spontaneous emission, so low number densities of the selected atoms can be detected and measured. Good spatial resolution can be achieved by using a narrow laser beam. If the laser is sufficiently monochromatic, and it can be tuned over the absorption line profile of the selected atoms, information can also be obtained about the velocities of the atoms from the Doppler effect which can broaden and shift the line. In this report two topics are examined in detail. The first is the effect of high laser irradiance, which can cause 'power broadening' of the apparent absorption line profile. The second is the effect of the high magnetic field in FTU. Detailed calculations are given for LIFS of neutral iron and molybdenum atoms, including the Zeeman effect, and the implementation of LIFS for these atoms on FTU is discussed

  11. APD detectors for biological fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Mazeres, S.; Borrel, V.; Magenc, C.; Courrech, J.L.; Bazer-Bachi, R.

    2006-01-01

    Fluorescence spectroscopy is a very convenient and widely used method for studying the molecular background of biological processes [L. Salome, J.L. Cazeil, A. Lopez, J.F. Tocanne, Eur. Biophys. J. 27 (1998) 391-402]. Chromophores are included in the structure under study and a flash of laser light induces fluorescence (Fluorescence Recovery After Photo-bleaching), the decay of which yields information on the polarity, the speed of rotation, and the speed of diffusion as well as on the temporal and spatial evolution of interactions between molecular species. The method can even be used to study living cells [J.F. Tocanne, L. Cezanne, A. Lopez, Prog. Lipid Res. 33 (1994) 203-237, L. Cezanne, A. Lopez, F. Loste, G. Parnaud, O. Saurel, P. Demange, J.F. Tocanne, Biochemistry 38 (1999) 2779-2786]. This is classically performed with a PM-based system. For biological reasons a decrease of the excitation of the cells is highly desirable. Because the fluorescence response then becomes fainter a significant improvement in detector capability would be welcome. We present here results obtained with an Avalanche Photo Diode (APD)-based system. The small sensitive area of detection allows a very significant improvement in signal/noise ratio, improvement in gain, and the opening-up of a new parameter space. With these new detectors we can begin the study of information transmission between cells through morphine receptors. This work involves both electronics engineers and biophysicists, so results and techniques in both fields will be presented here

  12. Laser fluorescence spectroscopy of sputtered uranium atoms

    International Nuclear Information System (INIS)

    Wright, R.B.; Pellin, M.J.; Gruen, D.M.; Young, C.E.

    1979-01-01

    Laser induced fluorescence (LIF) spectroscopy was used to study the sputtering of 99.8% 238 U metal foil when bombarded by normally incident 500 to 3000 eV Ne + , Ar + , Kr + , and O 2 + . A three-level atom model of the LIF processes is developed to interpret the observed fluorescent emission from the sputtered species. The model shows that close attention must be paid to the conditions under which the experiment is carried out as well as to the details of the collision cascade theory of sputtering. Rigorous analysis shows that when properly applied, LIF can be used to investigate the predictions of sputtering theory as regards energy distributions of sputtered particles and for the determination of sputtering yields. The possibility that thermal emission may occur during sputtering can also be tested using the proposed model. It is shown that the velocity distribution (either the number density or flux density distribution, depending upon the experimental conditions) of the sputtered particles can be determined using the LIF technique and that this information can be used to obtain a description of the basic sputtering mechanisms. These matters are discussed using the U-atom fluorescence measurements as a basis. The relative sputtering yields for various incident ions on uranium were also measured for the first time using the LIF technique. A surprisingly high fraction of the sputtered uranium atoms were found to occupy the low lying metastable energy levels of U(I). The population of the sputtered metastable atoms were found approximately to obey a Boltzman distribution with an effective temperature of 920 +- 100 0 K. 41 references

  13. Single Molecule Spectroscopy of Fluorescent Proteins

    NARCIS (Netherlands)

    Blum, Christian; Subramaniam, Vinod

    2009-01-01

    The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject to intense research. Understanding the

  14. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

    Science.gov (United States)

    Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

    2017-04-15

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Two-focus fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Dertinger, T.

    2007-05-01

    Fluorescence Correlation Spectroscopy (FCS) has been invented more than 30 years ago and experienced a renaissance after stable and affordable laser sources and low-noise single-photon detectors have become available. Its ability to measure diffusion coefficients at nanomolar concentrations of analyte made it a widely used tool in biophysics. However, in recent years it has been shown by many authors that aberrational (e.g. astigmatism) and photophysical effects (e.g. optical saturation) may influence the result of an FCS experiment dramatically, so that a precise and reliable estimation of the diffusion coefficient is no longer possible. In this thesis, we report on the development, implementation, and application of a new and robust modification of FCS that we termed two-focus FCS (2fFCS) and which fulfils two requirements: (i) It introduces an external ruler into the measurement by generating two overlapping laser foci of precisely known and fixed distance. (ii) These two foci and corresponding detection regions are generated in such a way that the corresponding molecule detection functions (MDFs) are sufficiently well described by a simple two-parameter model yielding accurate diffusion coefficients when applied to 2fFCS data analysis. Both these properties enable us to measure absolute values of the diffusion coefficient with an accuracy of a few percent. Moreover, it will turn out that the new technique is robust against refractive index mismatch, coverslide thickness deviations, and optical saturation effects, which so often trouble conventional FCS measurements. This thesis deals mainly with the introduction of the new measurement scheme, 2fFCS, but also presents several applications with far-reaching importance. (orig.)

  16. Two-focus fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dertinger, T.

    2007-05-15

    Fluorescence Correlation Spectroscopy (FCS) has been invented more than 30 years ago and experienced a renaissance after stable and affordable laser sources and low-noise single-photon detectors have become available. Its ability to measure diffusion coefficients at nanomolar concentrations of analyte made it a widely used tool in biophysics. However, in recent years it has been shown by many authors that aberrational (e.g. astigmatism) and photophysical effects (e.g. optical saturation) may influence the result of an FCS experiment dramatically, so that a precise and reliable estimation of the diffusion coefficient is no longer possible. In this thesis, we report on the development, implementation, and application of a new and robust modification of FCS that we termed two-focus FCS (2fFCS) and which fulfils two requirements: (i) It introduces an external ruler into the measurement by generating two overlapping laser foci of precisely known and fixed distance. (ii) These two foci and corresponding detection regions are generated in such a way that the corresponding molecule detection functions (MDFs) are sufficiently well described by a simple two-parameter model yielding accurate diffusion coefficients when applied to 2fFCS data analysis. Both these properties enable us to measure absolute values of the diffusion coefficient with an accuracy of a few percent. Moreover, it will turn out that the new technique is robust against refractive index mismatch, coverslide thickness deviations, and optical saturation effects, which so often trouble conventional FCS measurements. This thesis deals mainly with the introduction of the new measurement scheme, 2fFCS, but also presents several applications with far-reaching importance. (orig.)

  17. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    Directory of Open Access Journals (Sweden)

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  18. Fluorescence Lifetime Correlation Spectroscopy (FLCS): Concepts, Applications and Outlook

    Czech Academy of Sciences Publication Activity Database

    Kapusta, Peter; Macháň, Radek; Benda, A.; Hof, Martin

    2012-01-01

    Roč. 13, č. 10 (2012), s. 12890-12910 E-ISSN 1422-0067 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : fluorescence correlation spectroscopy (FCS) * time correlated single photon counting (TCSPC) * fluorescence cross-correlation spectroscopy (FCCS) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.464, year: 2012

  19. Detection of Counterfeit Tequila by Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    José Manuel de la Rosa Vázquez

    2015-01-01

    Full Text Available An ultraviolet (UV light induced fluorescence study to discriminate fake tequila from genuine ones is presented. A portable homemade system based on four light emitting diodes (LEDs from 255 to 405 nm and a miniature spectrometer was used. It has been shown that unlike fake and silver tequila, which produce weak fluorescence signal, genuine mixed, rested, and aged tequilas show high fluorescence emission in the range from 400 to 750 nm. The fluorescence intensity grows with aging in 100% agave tequila. Such fluorescence differences can even be observed with naked eyes. The presented results demonstrate that the fluorescence measurement could be a good method to detect counterfeit tequila.

  20. Monitoring organic loading to swimming pools by fluorescence excitation–emission matrix with parallel factor analysis (PARAFAC)

    DEFF Research Database (Denmark)

    Seredynska-Sobecka, Bozena; Stedmon, Colin; Boe-Hansen, Rasmus

    2011-01-01

    Fluorescence Excitation–Emission Matrix spectroscopy combined with parallel factor analysis was employed to monitor water quality and organic contamination in swimming pools. The fluorescence signal of the swimming pool organic matter was low but increased slightly through the day. The analysis...... revealed that the organic matter fluorescence was characterised by five different components, one of which was unique to swimming pool organic matter and one which was specific to organic contamination. The latter component had emission peaks at 420nm and was found to be a sensitive indicator of organic...... loading in swimming pool water. The fluorescence at 420nm gradually increased during opening hours and represented material accumulating through the day....

  1. Experimental station for gas phase fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Stankiewicz, M.; Garcia, E. Melero; Ruiz, J. Alvarez; Erman, P.; Hatherly, P.A.; Kivimaeki, A.; Rachlew, E.; Rius i Riu, J.

    2004-01-01

    The details of an experimental setup for gas phase atomic and molecular fluorescence measurements using synchrotron radiation are described in this article. The most significant part of the apparatus is an optical arrangement, which allows for simultaneous measurements of dispersed as well as total fluorescence intensity using an effusive gas jet and an inbuilt gas cell assembled in a convenient plug and measure configuration. The first measurements concerning fluorescence of the N 2 molecule around the N 1s edge obtained with this setup are presented

  2. Fluorescence Intrinsic Characterization of Excitation-Emission Matrix Using Multi-Dimensional Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Tzu-Chien Hsiao

    2013-11-01

    Full Text Available Excitation-emission matrix (EEM fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds due to overlapping features. Conventional studies use principal component analysis (PCA for EEM fluorescence analysis, and the relationship between the EEM features extracted by PCA and diseases has been examined. The spectral features of different tissue constituents are not fully separable or clearly defined. Recently, a non-stationary method called multi-dimensional ensemble empirical mode decomposition (MEEMD was introduced; this method can extract the intrinsic oscillations on multiple spatial scales without loss of information. The aim of this study was to propose a fluorescence spectroscopy system for EEM measurements and to describe a method for extracting the intrinsic characteristics of EEM by MEEMD. The results indicate that, although PCA provides the principal factor for the spectral features associated with chemical compounds, MEEMD can provide additional intrinsic features with more reliable mapping of the chemical compounds. MEEMD has the potential to extract intrinsic fluorescence features and improve the detection of biochemical changes.

  3. [Rapid identification of hogwash oil by using synchronous fluorescence spectroscopy].

    Science.gov (United States)

    Sun, Yan-Hui; An, Hai-Yang; Jia, Xiao-Li; Wang, Juan

    2012-10-01

    To identify hogwash oil quickly, the characteristic delta lambda of hogwash oil was analyzed by three dimensional fluorescence spectroscopy with parallel factor analysis, and the model was built up by using synchronous fluorescence spectroscopy with support vector machines (SVM). The results showed that the characteristic delta lambda of hogwash oil was 60 nm. Collecting original spectrum of different samples under the condition of characteristic delta lambda 60 nm, the best model was established while 5 principal components were selected from original spectrum and the radial basis function (RBF) was used as the kernel function, and the optimal penalty factor C and kernel function g were 512 and 0.5 respectively obtained by the grid searching and 6-fold cross validation. The discrimination rate of the model was 100% for both training sets and prediction sets. Thus, it is quick and accurate to apply synchronous fluorescence spectroscopy to identification of hogwash oil.

  4. U(IV) fluorescence spectroscopy. A new speciation tool

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

  5. Assessment of the unidentified organic matter fraction in fogwater using fluorescence spectroscopy

    Science.gov (United States)

    Valsaraj, K.; Birdwell, J.

    2010-07-01

    Dissolved organic matter (DOM) in fogwaters from southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix (EEM) fluorescence spectroscopy. The results demonstrate that fluorescence spectroscopy can be used to obtain a qualitative assessment of the large fraction of fogwater organic carbon (~40 - 80% by weight) that cannot be identified in terms of specific chemical compounds. The method has the principle advantage that it can be applied at natural abundance concentrations, thus eliminating the need for large sample volumes required to isolate DOM for characterization by other spectroscopic (NMR, FTIR) and chemical (elemental) analyses. It was anticipated that the fogwater organic matter fluorescence spectra would resemble those of surface and rain waters, containing peaks indicative of both humic substances and fluorescent amino acids. Humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices had values comparable to other natural waters. Biological character (intensity of tyrosine and tryptophan peaks) was found to increase with organic carbon concentration. Fogwater organic matter appears to contain a mixture of terrestrially- and microbially-derived material. The fluorescence results show that most of the unidentified fogwater organic carbon can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems.

  6. Distribution of diffusion times determined by fluorescence (lifetime) correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Pánek, Jiří; Loukotová, Lenka; Hrubý, Martin; Štěpánek, Petr

    2018-01-01

    Roč. 51, č. 8 (2018), s. 2796-2804 ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : polymer solution * fluorescence correlation spectroscopy * diffusion time distribution Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 5.835, year: 2016

  7. "FluSpec": A Simulated Experiment in Fluorescence Spectroscopy

    Science.gov (United States)

    Bigger, Stephen W.; Bigger, Andrew S.; Ghiggino, Kenneth P.

    2014-01-01

    The "FluSpec" educational software package is a fully contained tutorial on the technique of fluorescence spectroscopy as well as a simulator on which experiments can be performed. The procedure for each of the experiments is also contained within the package along with example analyses of results that are obtained using the software.

  8. Matrix Isolation Spectroscopy Applied to Positron Moderatioin in Cryogenic Solids

    Science.gov (United States)

    2011-07-01

    Current Positron Applications • 2-γ decay exploited in Positron Emission Tomography (PET) scanners. • Positrons localize & annihilate preferentially at...Air Force  Eglin Air Force Base AFRL-RW-EG-TP-2011-024 Matrix Isolation Spectroscopy Applied to Positron Moderation in Cryogenic Solids Distribution... Spectroscopy Applied to Positron Moderation in Cryogenic Solids 5a. CONTRACT NUMBER 5b. GRANT NUMBER 62602F 5c. PROGRAM ELEMENT NUMBER 6

  9. Emerging biomedical applications of time-resolved fluorescence spectroscopy

    Science.gov (United States)

    Lakowicz, Joseph R.; Szmacinski, Henryk; Koen, Peter A.

    1994-07-01

    Time-resolved fluorescence spectroscopy is presently regarded as a research tool in biochemistry, biophysics, and chemical physics. Advances in laser technology, the development of long-wavelength probes, and the use of lifetime-based methods are resulting in the rapid migration of time-resolved fluorescence to the clinical chemistry lab, to the patient's bedside, to flow cytometers, to the doctor's office, and even to home health care. Additionally, time-resolved imaging is now a reality in fluorescence microscopy, and will provide chemical imaging of a variety of intracellular analytes and/or cellular phenomena. In this overview paper we attempt to describe some of the opportunities available using chemical sensing based on fluorescence lifetimes, and to predict those applications of lifetime-based sensing which are most likely in the near future.

  10. Application of fluorescent and vibration spectroscopy for septic serum human albumin structure deformation during pathology

    Science.gov (United States)

    Zyubin, A.; Konstantinova, E.; Slezhkin, V.; Matveeva, K.; Samusev, I.; Bryukhanov, V.

    2017-12-01

    In this paper we perform results of conformational analysis of septic human serum albumin (HSA) carried out by Raman spectroscopy (RS), infrared (IR) spectroscopy and fluorescent spectroscopy. The main vibrational groups were identified and analyzed for septic HSA and its health control. Comparison between Raman and IR results were done. Fluorescent spectral changes of Trp-214 group were analyzed. Application of Raman, IR spectroscopy, fluorescent spectroscopy for conformational changes study of HSA during pathology were shown.

  11. Emerging applications of fluorescence spectroscopy in medical microbiology field.

    Science.gov (United States)

    Shahzad, Aamir; Köhler, Gottfried; Knapp, Martin; Gaubitzer, Erwin; Puchinger, Martin; Edetsberger, Michael

    2009-11-26

    There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

  12. Emerging applications of fluorescence spectroscopy in medical microbiology field

    Directory of Open Access Journals (Sweden)

    Gaubitzer Erwin

    2009-11-01

    Full Text Available Abstract There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity.

  13. The measurement of X-rays radiation temperature with a new developed filter-fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Zhang Chuanfei; Lin Libin; Lou Fuhong; Peng Taiping

    2001-01-01

    The author introduces how to measure the energy spectra of X-rays by filter-fluorescence spectroscopy. The design principle and structure of new-developed double diaphragms and filter-fluorescence spectroscopy with 5 channels are depicted. The parameters of optimized spectroscopy by numerical method are given. The filter-fluorescence spectroscopy designed according as Rousseau balance principle improves signal-noises ratio

  14. Laser-excited fluorescence spectroscopy of oxide glasses

    International Nuclear Information System (INIS)

    Weber, M.J.

    1977-01-01

    Laser-induced fluorescence line narrowing was applied to investigate the local fields and interactions of paramagnetic ions in oxide glasses. Studies included the site dependence of energy levels, radiative and nonradiative transition probabilities, homogeneous line broadening, and ion--ion energy transfer of rare earth ions. These results and the experimental techniques are reviewed briefly; the use of paramagnetic ions other than the rare earths is also considered. Recently, laser-excited fluorescence spectroscopy was used to investigate modifications in the local structure of lithium borate glass caused by compositional changes and phase separation and the site dependence of nonradiative relaxation of paramagnetic ions by multiphonon processes. These results and their implications are discussed. 6 figures

  15. Quantum process tomography by 2D fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pachón, Leonardo A. [Grupo de Física Atómica y Molecular, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Andrew H. [Department of Chemistry and Biochemistry, Oregon Center for Optics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 (United States); Aspuru-Guzik, Alán [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-06-07

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

  16. Quantum process tomography by 2D fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Pachón, Leonardo A.; Marcus, Andrew H.; Aspuru-Guzik, Alán

    2015-01-01

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed

  17. Determination of antioxidant content in biodiesel by fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Keurison F.; Caires, Anderson R.L. [Universidade Federal da Grande Dourados, MS (Brazil). Grupo de Optica Aplicada; Oliveira, Samuel L. [Universidade Federal de Mato Grosso do Sul (UFMS), MS (Brazil). Grupo de Optica e Fotonica

    2011-07-01

    Full text. Biodiesel is an alternative fuel composed by mono-alkyl esters obtained from vegetable oils or animal fats. Due to its chemical structure, biodiesel is highly susceptible to oxidation which leads to formation of insoluble gums and sediments that can block the filter system of fuel injection. Biodiesel made from vegetable oils typically has a small amount of natural antioxidants so that it is necessary to add synthetic antioxidants to enhance its stability and retain their properties for a longer period. The main antioxidants are synthetic phenolic compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) as well as natural antioxidants as tocopherols. The fluorescence spectroscopy has been applied for determination of phenolic compounds in oils. Here, a method based on fluorescence is proposed to quantify the BHA and TBHQ antioxidant concentration in biodiesel produced from sunflower and soybean oils. Soybean and sunflower biodiesel were obtained by transesterification of fatty alcohol in the presence of NaOH as catalyst. The reactions were carried out in the molar ratio of 6:1 methanol/oil. After the production and purification, biodiesel samples were stored. Biodiesel samples with BHA and TBHQ concentrations from 1000 to 8000 ppm (m/m) were pre- pared. These samples were diluted in ethanol (95%) in order to measure the fluorescence spectra. Fluorescence and excitation spectra of the solutions were recorded at room temperature using a spectrofluorimeter. The emission spectra were obtained under excitation at about 310nm and fluorescence in the 320-800nm range was evaluated. Biodiesel samples without BHA and TBHQ showed fluorescence band at about 420nm, which can be attributed to tocopherols inherent to the vegetable oils used in the biodiesel production. The addition of BHA and/or TBHQ is responsible for the appearance of a fluorescence band around 330nm. It was verified that the fluorescence

  18. Time-resolved laser fluorescence spectroscopy of organic ligands by europium: Fluorescence quenching and lifetime properties

    Science.gov (United States)

    Nouhi, A.; Hajjoul, H.; Redon, R.; Gagné, J. P.; Mounier, S.

    2018-03-01

    Time-resolved Laser Fluorescence Spectroscopy (TRLFS) has proved its usefulness in the fields of biophysics, life science and geochemistry to characterize the fluorescence probe molecule with its chemical environment. The purpose of this study is to demonstrate the applicability of this powerful technique combined with Steady-State (S-S) measurements. A multi-mode factor analysis, in particular CP/PARAFAC, was used to analyze the interaction between Europium (Eu) and Humic substances (HSs) extracted from Saint Lawrence Estuary in Canada. The Saint Lawrence system is a semi-enclosed water stream with connections to the Atlantic Ocean and is an excellent natural laboratory. CP/PARAFAC applied to fluorescence S-S data allows introspecting ligands-metal interactions and the one-site 1:1 modeling gives information about the stability constants. From the spectral signatures and decay lifetimes data given by TRLFS, one can deduce the fluorescence quenching which modifies the fluorescence and discuss its mechanisms. Results indicated a relatively strong binding ability between europium and humic substances samples (Log K value varies from 3.38 to 5.08 at pH 7.00). Using the Stern-Volmer plot, it has been concluded that static and dynamic quenching takes places in the case of salicylic acid and europium interaction while for HSs interaction only a static quenching is observed.

  19. Assessment of hyaline cartilage matrix composition using near infrared spectroscopy.

    Science.gov (United States)

    Palukuru, Uday P; McGoverin, Cushla M; Pleshko, Nancy

    2014-09-01

    Changes in the composition of the extracellular matrix (ECM) are characteristic of injury or disease in cartilage tissue. Various imaging modalities and biochemical techniques have been used to assess the changes in cartilage tissue but lack adequate sensitivity, or in the case of biochemical techniques, result in destruction of the sample. Fourier transform near infrared (FT-NIR) spectroscopy has shown promise for the study of cartilage composition. In the current study NIR spectroscopy was used to identify the contributions of individual components of cartilage in the NIR spectra by assessment of the major cartilage components, collagen and chondroitin sulfate, in pure component mixtures. The NIR spectra were obtained using homogenous pellets made by dilution with potassium bromide. A partial least squares (PLS) model was calculated to predict composition in bovine cartilage samples. Characteristic absorbance peaks between 4000 and 5000 cm(-1) could be attributed to components of cartilage, i.e. collagen and chondroitin sulfate. Prediction of the amount of collagen and chondroitin sulfate in tissues was possible within 8% (w/dw) of values obtained by gold standard biochemical assessment. These results support the use of NIR spectroscopy for in vitro and in vivo applications to assess matrix composition of cartilage tissues, especially when tissue destruction should be avoided. Copyright © 2014. Published by Elsevier B.V.

  20. Classification of plum spirit drinks by synchronous fluorescence spectroscopy.

    Science.gov (United States)

    Sádecká, J; Jakubíková, M; Májek, P; Kleinová, A

    2016-04-01

    Synchronous fluorescence spectroscopy was used in combination with principal component analysis (PCA) and linear discriminant analysis (LDA) for the differentiation of plum spirits according to their geographical origin. A total of 14 Czech, 12 Hungarian and 18 Slovak plum spirit samples were used. The samples were divided in two categories: colorless (22 samples) and colored (22 samples). Synchronous fluorescence spectra (SFS) obtained at a wavelength difference of 60 nm provided the best results. Considering the PCA-LDA applied to the SFS of all samples, Czech, Hungarian and Slovak colorless samples were properly classified in both the calibration and prediction sets. 100% of correct classification was also obtained for Czech and Hungarian colored samples. However, one group of Slovak colored samples was classified as belonging to the Hungarian group in the calibration set. Thus, the total correct classifications obtained were 94% and 100% for the calibration and prediction steps, respectively. The results were compared with those obtained using near-infrared (NIR) spectroscopy. Applying PCA-LDA to NIR spectra (5500-6000 cm(-1)), the total correct classifications were 91% and 92% for the calibration and prediction steps, respectively, which were slightly lower than those obtained using SFS. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Rapid measurement of meat spoilage using fluorescence spectroscopy

    Science.gov (United States)

    Wu, Binlin; Dahlberg, Kevin; Gao, Xin; Smith, Jason; Bailin, Jacob

    2017-02-01

    Food spoilage is mainly caused by microorganisms, such as bacteria. In this study, we measure the autofluorescence in meat samples longitudinally over a week in an attempt to develop a method to rapidly detect meat spoilage using fluorescence spectroscopy. Meat food is a biological tissue, which contains intrinsic fluorophores, such as tryptophan, collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) etc. As meat spoils, it undergoes various morphological and chemical changes. The concentrations of the native fluorophores present in a sample may change. In particular, the changes in NADH and FAD are associated with microbial metabolism, which is the most important process of the bacteria in food spoilage. Such changes may be revealed by fluorescence spectroscopy and used to indicate the status of meat spoilage. Therefore, such native fluorophores may be unique, reliable and nonsubjective indicators for detection of spoiled meat. The results of the study show that the relative concentrations of all above fluorophores change as the meat samples kept in room temperature ( 19° C) spoil. The changes become more rapidly after about two days. For the meat samples kept in a freezer ( -12° C), the changes are much less or even unnoticeable over a-week-long storage.

  2. Fluorescence Spectroscopy and Chemometric Modeling for Bioprocess Monitoring

    Directory of Open Access Journals (Sweden)

    Saskia M. Faassen

    2015-04-01

    Full Text Available On-line sensors for the detection of crucial process parameters are desirable for the monitoring, control and automation of processes in the biotechnology, food and pharma industry. Fluorescence spectroscopy as a highly developed and non-invasive technique that enables the on-line measurements of substrate and product concentrations or the identification of characteristic process states. During a cultivation process significant changes occur in the fluorescence spectra. By means of chemometric modeling, prediction models can be calculated and applied for process supervision and control to provide increased quality and the productivity of bioprocesses. A range of applications for different microorganisms and analytes has been proposed during the last years. This contribution provides an overview of different analysis methods for the measured fluorescence spectra and the model-building chemometric methods used for various microbial cultivations. Most of these processes are observed using the BioView® Sensor, thanks to its robustness and insensitivity to adverse process conditions. Beyond that, the PLS-method is the most frequently used chemometric method for the calculation of process models and prediction of process variables.

  3. Fluorescence Spectroscopy and Chemometric Modeling for Bioprocess Monitoring

    Science.gov (United States)

    Faassen, Saskia M.; Hitzmann, Bernd

    2015-01-01

    On-line sensors for the detection of crucial process parameters are desirable for the monitoring, control and automation of processes in the biotechnology, food and pharma industry. Fluorescence spectroscopy as a highly developed and non-invasive technique that enables the on-line measurements of substrate and product concentrations or the identification of characteristic process states. During a cultivation process significant changes occur in the fluorescence spectra. By means of chemometric modeling, prediction models can be calculated and applied for process supervision and control to provide increased quality and the productivity of bioprocesses. A range of applications for different microorganisms and analytes has been proposed during the last years. This contribution provides an overview of different analysis methods for the measured fluorescence spectra and the model-building chemometric methods used for various microbial cultivations. Most of these processes are observed using the BioView® Sensor, thanks to its robustness and insensitivity to adverse process conditions. Beyond that, the PLS-method is the most frequently used chemometric method for the calculation of process models and prediction of process variables. PMID:25942644

  4. Mapping the dynamical organization of the cell nucleus through fluorescence correlation spectroscopy.

    Science.gov (United States)

    Stortz, Martin; Angiolini, Juan; Mocskos, Esteban; Wolosiuk, Alejandro; Pecci, Adali; Levi, Valeria

    2018-05-01

    The hierarchical organization of the cell nucleus into specialized open reservoirs and the nucleoplasm overcrowding impose restrictions to the mobility of biomolecules and their interactions with nuclear targets. These properties determine that many nuclear functions such as transcription, replication, splicing or DNA repair are regulated by complex, dynamical processes that do not follow simple rules. Advanced fluorescence microscopy tools and, in particular, fluorescence correlation spectroscopy (FCS) provide complementary and exquisite information on the dynamics of fluorescent labeled molecules moving through the nuclear space and are helping us to comprehend the complexity of the nuclear structure. Here, we describe how FCS methods can be applied to reveal the dynamical organization of the nucleus in live cells. Specifically, we provide instructions for the preparation of cellular samples with fluorescent tagged proteins and detail how FCS can be easily instrumented in commercial confocal microscopes. In addition, we describe general rules to set the parameters for one and two-color experiments and the required controls for these experiments. Finally, we review the statistical analysis of the FCS data and summarize the use of numerical simulations as a complementary approach that helps us to understand the complex matrix of molecular interactions network within the nucleus. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Two-dimensional fluorescence lifetime correlation spectroscopy. 2. Application.

    Science.gov (United States)

    Ishii, Kunihiko; Tahara, Tahei

    2013-10-03

    In the preceding article, we introduced the theoretical framework of two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS). In this article, we report the experimental implementation of 2D FLCS. In this method, two-dimensional emission-delay correlation maps are constructed from the photon data obtained with the time-correlated single photon counting (TCSPC), and then they are converted to 2D lifetime correlation maps by the inverse Laplace transform. We develop a numerical method to realize reliable transformation, employing the maximum entropy method (MEM). We apply the developed actual 2D FLCS to two real systems, a dye mixture and a DNA hairpin. For the dye mixture, we show that 2D FLCS is experimentally feasible and that it can identify different species in an inhomogeneous sample without any prior knowledge. The application to the DNA hairpin demonstrates that 2D FLCS can disclose microsecond spontaneous dynamics of biological molecules in a visually comprehensible manner, through identifying species as unique lifetime distributions. A FRET pair is attached to the both ends of the DNA hairpin, and the different structures of the DNA hairpin are distinguished as different fluorescence lifetimes in 2D FLCS. By constructing the 2D correlation maps of the fluorescence lifetime of the FRET donor, the equilibrium dynamics between the open and the closed forms of the DNA hairpin is clearly observed as the appearance of the cross peaks between the corresponding fluorescence lifetimes. This equilibrium dynamics of the DNA hairpin is clearly separated from the acceptor-missing DNA that appears as an isolated diagonal peak in the 2D maps. The present study clearly shows that newly developed 2D FLCS can disclose spontaneous structural dynamics of biological molecules with microsecond time resolution.

  6. Fluorescence Spectroscopy, Exciton Dynamics and Photochemistry of Single Allophycocyanin Trimers

    International Nuclear Information System (INIS)

    Ying, Liming; Xie, Xiaoliang

    1998-01-01

    We report a study of the spectroscopy and exciton dynamics of the allophycocyanin trimer (APC), a light harvesting protein complex from cyanobacteria, by room-temperature single-molecule measurements of fluorescence spectra, lifetimes, intensity trajectories and polarization modulation. Emission spectra of individual APC trimers are found to be homogeneous on the time scale of seconds. In contrast, their emission lifetimes are found to be widely distributed, because of generation of exciton traps during the course of measurements. The intensity trajectories and polarization modulation experiments indicate reversible ixciton trap formation within the three quasi-independent pairs of strong interacting a84 and B84 chromophores in APC, as well a photobleaching of individual chromophores. Comparison experiments under continuous wave and pulsed excitation reveal a two-photon mechanism for generating exciton traps and/or photobleaching, which involves exciton-exciton annihilation. These single-molecule experiments provide new insights into exciton dynamics and photochemistry of light-harvesting complexes

  7. Application of ultraviolet fluorometry and excitation-emission matrix spectroscopy (EEMS) to fingerprint oil and chemically dispersed oil in seawater.

    Science.gov (United States)

    Bugden, J B C; Yeung, C W; Kepkay, P E; Lee, K

    2008-04-01

    Excitation-emission matrix spectroscopy (EEMS) was used to characterize the ultra violet fluorescence fingerprints of eight crude oils (with a 14,470-fold range of dynamic viscosity) in seawater. When the chemical dispersant Corexit 9500 was mixed with the oils prior to their dispersion in seawater, the fingerprints of each oil changed primarily as an increase in fluorescence over an emission band centered on 445 nm. In order to simplify the wealth of information available in the excitation-emission matrix spectra (EEMs), two ratios were calculated. A 66-90% decrease in the slope ratio was observed with the addition of Corexit. When the slope ratios were reduced in complexity to intensity ratios, similar trends were apparent. As a result either of the ratios could be used as a simple and rapid means of identifying and monitoring chemically dispersed oil in the open ocean.

  8. Feasibility of the simultaneous determination of polycyclic aromatic hydrocarbons based on two-dimensional fluorescence correlation spectroscopy

    Science.gov (United States)

    Yang, Renjie; Dong, Guimei; Sun, Xueshan; Yang, Yanrong; Yu, Yaping; Liu, Haixue; Zhang, Weiyu

    2018-02-01

    A new approach for quantitative determination of polycyclic aromatic hydrocarbons (PAHs) in environment was proposed based on two-dimensional (2D) fluorescence correlation spectroscopy in conjunction with multivariate method. 40 mixture solutions of anthracene and pyrene were prepared in the laboratory. Excitation-emission matrix (EEM) fluorescence spectra of all samples were collected. And 2D fluorescence correlation spectra were calculated under the excitation perturbation. The N-way partial least squares (N-PLS) models were developed based on 2D fluorescence correlation spectra, showing a root mean square error of calibration (RMSEC) of 3.50 μg L- 1 and root mean square error of prediction (RMSEP) of 4.42 μg L- 1 for anthracene and of 3.61 μg L- 1 and 4.29 μg L- 1 for pyrene, respectively. Also, the N-PLS models were developed for quantitative analysis of anthracene and pyrene using EEM fluorescence spectra. The RMSEC and RMSEP were 3.97 μg L- 1 and 4.63 μg L- 1 for anthracene, 4.46 μg L- 1 and 4.52 μg L- 1 for pyrene, respectively. It was found that the N-PLS model using 2D fluorescence correlation spectra could provide better results comparing with EEM fluorescence spectra because of its low RMSEC and RMSEP. The methodology proposed has the potential to be an alternative method for detection of PAHs in environment.

  9. Fluorescence spectroscopy and confocal microscopy of the mycotoxin citrinin in condensed phase and hydrogel films.

    Science.gov (United States)

    Lauer, Milena H; Gehlen, Marcelo H; de Jesus, Karen; Berlinck, Roberto G S

    2014-05-01

    The emission spectra, quantum yields and fluorescence lifetimes of citrinin in organic solvents and hydrogel films have been determined. Citrinin shows complex fluorescence decays due to the presence of two tautomers in solution and interconversion from excited-state double proton transfer (ESDPT) process. The fluorescence decay times associated with the two tautomers have values near 1 and 5 ns depending on the medium. In hydrogel films of agarose and alginate, fluorescence imaging showed that citrinin is not homogeneously dispersed and highly emissive micrometer spots may be formed. Fluorescence spectrum and decay analysis are used to recognize the presence of citrinin in hydrogel films using confocal fluorescence microscopy and spectroscopy.

  10. Quantitative analysis by X-ray fluorescence using first principles for matrix correction

    International Nuclear Information System (INIS)

    Hulett, L.D.; Dunn, H.W.; Tarter, J.G.

    1978-01-01

    The quantitative interpretation of X-ray fluorescence (XRF) data is often difficult because of matrix effects. The intensity of fluorescence measured for a given element is not only dependent on the element's concentration, but also on the mass absorption coefficients of the sample for the excitation and fluorescence radiation. Also, there are interelement effects in which high-energy fluorescence from heavier elements is absorbed by lighter elements with a resulting enhancement of their fluorescence. Recent theoretical treatments of this problem have shown that X-ray fluorescence data can be corrected for these matrix effects by calculations based on first principles. Fundamental constants, available in atomic physics data tables, are the only parameters needed. It is not necessary to make empirical calibrations. The application of this correctional procedure to alloys and alumina-supported catalysts is described. A description is given of a low-background spectrometer which uses monochromatic Ag Ksub(α) radiation for excitation. Matrix corrections by first principles can be easily applied to data from instruments of this type because fluorescence excitation cross-sections and mass absorption coefficients can be accurately defined for monochromatic radiation. (author)

  11. Characterization of type I, II, III, IV, and V collagens by time-resolved laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Marcu, Laura; Cohen, David; Maarek, Jean-Michel I.; Grundfest, Warren S.

    2000-04-01

    The relative proportions of genetically distinct collagen types in connective tissues vary with tissue type and change during disease progression, development, wound healing, aging. This study aims to 1) characterize the spectro- temporal fluorescence emission of fiber different types of collagen and 2) assess the ability of time-resolved laser- induced fluorescence spectroscopy to distinguish between collagen types. Fluorescence emission of commercially available purified samples was induced with nitrogen laser excitation pulses and detected with a MCP-PMT connected to a digital storage oscilloscope. The recorded time-resolved emission spectra displayed distinct fluorescence emission characteristics for each collagen type. The time domain information complemented the spectral domain intensity data for improved discrimination between different collagen types. Our results reveal that analysis of the fluorescence emission can be used to characterize different species of collagen. Also, the results suggest that time-resolved spectroscopy can be used for monitoring of connective tissue matrix composition changes due to various pathological and non-pathological conditions.

  12. Inference of protein diffusion probed via fluorescence correlation spectroscopy

    Science.gov (United States)

    Tsekouras, Konstantinos

    2015-03-01

    Fluctuations are an inherent part of single molecule or few particle biophysical data sets. Traditionally, ``noise'' fluctuations have been viewed as a nuisance, to be eliminated or minimized. Here we look on how statistical inference methods - that take explicit advantage of fluctuations - have allowed us to draw an unexpected picture of single molecule diffusional dynamics. Our focus is on the diffusion of proteins probed using fluorescence correlation spectroscopy (FCS). First, we discuss how - in collaboration with the Bustamante and Marqusee labs at UC Berkeley - we determined using FCS data that individual enzymes are perturbed by self-generated catalytic heat (Riedel et al, Nature, 2014). Using the tools of inference, we found how distributions of enzyme diffusion coefficients shift in the presence of substrate revealing that enzymes performing highly exothermic reactions dissipate heat by transiently accelerating their center of mass following a catalytic reaction. Next, when molecules diffuse in the cell nucleus they often appear to diffuse anomalously. We analyze FCS data - in collaboration with Rich Day at the IU Med School - to propose a simple model for transcription factor binding-unbinding in the nucleus to show that it may give rise to apparent anomalous diffusion. Here inference methods extract entire binding affinity distributions for the diffusing transcription factors, allowing us to precisely characterize their interactions with different components of the nuclear environment. From this analysis, we draw key mechanistic insight that goes beyond what is possible by simply fitting data to ``anomalous diffusion'' models.

  13. Fluorescence spectroscopy and multi-way techniques. PARAFAC

    DEFF Research Database (Denmark)

    Murphy, Kathleen R.; Stedmon, Colin A.; Graeber, Daniel

    2013-01-01

    PARAllel FACtor analysis (PARAFAC) is increasingly used to decompose fluorescence excitation emission matrices (EEMs) into their underlying chemical components. In the ideal case where fluorescence conforms to Beers Law, this process can lead to the mathematical identification and quantification...

  14. A combined matrix isolation spectroscopy and cryosolid positron moderation apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Molek, Christopher D.; Michael Lindsay, C.; Fajardo, Mario E. [Air Force Research Laboratory, Munitions Directorate, Ordnance Division, Energetic Materials Branch, AFRL/RWME, 2306 Perimeter Road, Eglin AFB, Florida 32542-5910 (United States)

    2013-03-15

    We describe the design, construction, and operation of a novel apparatus for investigating efficiency improvements in thin-film cryogenic solid positron moderators. We report results from solid neon, argon, krypton, and xenon positron moderators which illustrate the capabilities and limitations of our apparatus. We integrate a matrix isolation spectroscopy diagnostic within a reflection-geometry positron moderation system. We report the optical thickness, impurity content, and impurity trapping site structures within our moderators determined from infrared absorption spectra. We use a retarding potential analyzer to modulate the flow of slow positrons, and report positron currents vs. retarding potential for the different moderators. We identify vacuum ultraviolet emissions from irradiated Ne moderators as the source of spurious signals in our channel electron multiplier slow positron detection channel. Our design is also unusual in that it employs a sealed radioactive Na-22 positron source which can be translated relative to, and isolated from, the cryogenic moderator deposition substrate. This allows us to separate the influences on moderator efficiency of surface contamination by residual gases from those of accumulated radiation damage.

  15. Membrane mobility and microdomain association of the dopamine transporter studied with fluorescence correlation spectroscopy and fluorescence recovery after photobleaching

    DEFF Research Database (Denmark)

    Adkins, Erika M; Samuvel, Devadoss J; Fog, Jacob U

    2007-01-01

    To investigate microdomain association of the dopamine transporter (DAT), we employed FCS (fluorescence correlation spectroscopy) and FRAP (fluorescence recovery after photobleaching). In non-neuronal cells (HEK293), FCS measurements revealed for the YFP-DAT (DAT tagged with yellow fluorescent...... protein) a diffusion coefficient (D) of approximately 3.6 x 10(-9) cm2/s, consistent with a relatively freely diffusible protein. In neuronally derived cells (N2a), we were unable to perform FCS measurements on plasma membrane-associated protein due to photobleaching, suggesting partial immobilization...

  16. Membrane mobility and microdomain association of the dopaminetransporter studied with fluorescence correlation spectroscopy and fluorescence recovery after photobleaching

    DEFF Research Database (Denmark)

    Adkins, Erika; Samuvel, Devadoss; Fog, Jacob

    2007-01-01

    To investigate microdomain association of the dopamine transporter (DAT), we employed FCS (fluorescence correlation spectroscopy) and FRAP (fluorescence recovery after photobleaching). In non-neuronal cells (HEK293), FCS measurements revealed for the YFP-DAT (DAT tagged with yellow fluorescent...... protein) a diffusion coefficient (D) of ~3.6 × 10-9 cm2/s, consistent with a relatively freely diffusible protein. In neuronally derived cells (N2a), we were unable to perform FCS measurements on plasma membrane-associated protein due to photobleaching, suggesting partial immobilization...

  17. The endogenous fluorescence of fibroblast in collagen gels as indicator of stiffness of the extracellular matrix

    Science.gov (United States)

    Padilla-Martinez, J. P.; Ortega-Martinez, A.; Franco, W.

    2016-03-01

    The stiffness or rigidity of the extracellular matrix (ECM) regulates cell response. Established mechanical tests to measure stiffness, such as indentation and tensile tests, are invasive and destructive to the sample. Endogenous or native molecules to cells and ECM components, like tryptophan and cross-links of collagen, display fluorescence upon irradiation with ultraviolet light. Most likely, the concentration of these endogenous fluorophores changes as the stiffness of the ECM changes. In this work we investigate the endogenous fluorescence of collagen gels containing fibroblasts as a non-invasive non-destructive method to measure stiffness of the ECM. Human fibroblast cells were cultured in three-dimensional gels of type I collagen (50,000 cells/ml). This construct is a simple model of tissue contraction. During contraction, changes in the excitation-emission matrix (a fluorescence map in the 240-520/290-530 nm range) of constructs were measured with a spectrofluoremeter, and changes in stiffness were measured with a standard indentation test over 16 days. Results show that a progressive increase in fluorescence of the 290/340 nm excitation-emission pair correlates with a progressive increase in stiffness (r=0.9, α=0.5). The fluorescence of this excitation-emission pair is ascribed to tryptophan and variations in the fluorescence of this pair correlate with cellular proliferation. In this tissue model, the endogenous functional fluorescence of proliferating fibroblast cells is a biomechanical marker of stiffness of the ECM.

  18. Discrimination of several Indonesian specialty coffees using Fluorescence Spectroscopy combined with SIMCA method

    Science.gov (United States)

    Suhandy, D.; Yulia, M.

    2018-03-01

    Indonesia is one of the important producers of several specialty coffees, which have a particularly high economic value, including Civet coffee (‘kopi luwak’ in Indonesian language) and Peaberry coffee (‘kopi lanang’ in Indonesian language). The production of Civet and Peaberry coffee is very limited. In order to provide authentication of Civet and Peaberry coffee and protect consumers from adulteration, a robust and easy method for evaluating ground Civet and Peaberry coffee and detection of its adulteration is needed. In this study, we investigate the use of fluorescence spectroscopy combined with SIMCA (soft independent modelling of class analogies) method to discriminate three Indonesian specialty coffee: ground Peaberry, Civet and Pagar Alam coffee. Total 90 samples were used (30 samples for Civet, Peaberry and Pagar Alam coffee, respectively). All coffee samples were ground using a home-coffee-grinder. Since particle size in coffee powder has a significant influence on the spectra obtained, we sieved all coffee samples through a nest of U. S. standard sieves (mesh number of 40) on a Meinzer II sieve shaker for 10 minutes to obtain a particle size of 420 µm. The experiments were performed at room temperature (around 27-29°C). All samples were extracted with distilled water and then filtered. For each samples, 3 mL of extracted sample then was pipetted into 10 mm cuvettes for spectral data acquisition. The EEM (excitation-emission matrix) spectral data of coffee samples were acquired using JASCO FP-8300 Fluorescence Spectrometer. The principal component analysis (PCA) result shows that it is possible to discriminate types of coffee based on information from EEM (excitation-emission matrix) spectral data. Using SIMCA method, the discrimination model of Indonesian specialty coffee was successfully developed and resulted in high performance of discrimination with 100% of sensitivity and specificity for Peaberry, Civet and Pagar Alam coffee. This research

  19. Semiconductor Nanomaterials-Based Fluorescence Spectroscopic and Matrix-Assisted Laser Desorption/Ionization (MALDI Mass Spectrometric Approaches to Proteome Analysis

    Directory of Open Access Journals (Sweden)

    Suresh Kumar Kailasa

    2013-12-01

    Full Text Available Semiconductor quantum dots (QDs or nanoparticles (NPs exhibit very unusual physico-chemcial and optical properties. This review article introduces the applications of semiconductor nanomaterials (NMs in fluorescence spectroscopy and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS for biomolecule analysis. Due to their unique physico-chemical and optical properties, semiconductors NMs have created many new platforms for investigating biomolecular structures and information in modern biology. These semiconductor NMs served as effective fluorescent probes for sensing proteins and cells and acted as affinity or concentrating probes for enriching peptides, proteins and bacteria proteins prior to MALDI-MS analysis.

  20. Fluorescent Water Soluble Polymers for Isozyme-Selective Interactions with Matrix Metalloproteinase-9

    Science.gov (United States)

    Dutta, Rinku; Scott, Michael D.; Haldar, Manas K.; Ganguly, Bratati; Srivastava, D. K.; Friesner, Daniel L.; Mallik, Sanku

    2011-01-01

    Matrix metalloproteinases (MMPs) are overexpressed in various pathological conditions, including various cancers. Although these isozymes have similar active sites, the patterns of exposed amino acids on their surfaces are different. Herein, we report the synthesis and molecular interactions of two water-soluble, fluorescent polymers which demonstrate selective interactions with MMP-9 compared to MMP-7 and -10. PMID:21367603

  1. Quantification of leakage from large unilamellar lipid vesicles by fluorescence correlation spectroscopy

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2014-01-01

    Fluorescence correlation spectroscopy (FCS) is a powerful experimental technique that in recent years has found numerous applications for studying biological phenomena. In this article, we scrutinize one of these applications, namely, FCS as a technique for studying leakage of fluorescent molecul...

  2. Using Quenching to Detect Corrosion on Sculptural Metalwork: A Real-World Application of Fluorescence Spectroscopy

    Science.gov (United States)

    Hensen, Cory; Clare, Tami Lasseter; Barbera, Jack

    2018-01-01

    Fluorescence spectroscopy experiments are a frequently taught as part of upper-division teaching laboratories. To expose undergraduate students to an applied fluorescence technique, a corrosion detection method, using quenching, was adapted from authentic research for an instrumental analysis laboratory. In the experiment, students acquire…

  3. Endogenous synchronous fluorescence spectroscopy (SFS) of basal cell carcinoma-initial study

    Science.gov (United States)

    Borisova, E.; Zhelyazkova, Al.; Keremedchiev, M.; Penkov, N.; Semyachkina-Glushkovskaya, O.; Avramov, L.

    2016-01-01

    The human skin is a complex, multilayered and inhomogeneous organ with spatially varying optical properties. Analysis of cutaneous fluorescence spectra could be a very complicated task; therefore researchers apply complex mathematical tools for data evaluation, or try to find some specific approaches, that would simplify the spectral analysis. Synchronous fluorescence spectroscopy (SFS) allows improving the spectral resolution, which could be useful for the biological tissue fluorescence characterization and could increase the tumour detection diagnostic accuracy.

  4. Visualizing the dental biofilm matrix by means of fluorescence lectin-binding analysis

    DEFF Research Database (Denmark)

    Tawakoli, Pune Nina; Neu, Thomas R; Busck, Mette Marie

    2017-01-01

    lectins to visualize and quantify extracellular glycoconjugates in dental biofilms. Lectin binding was screened on pooled supragingival biofilm samples collected from 76 subjects using confocal microscopy. FLBA was then performed with 10 selected lectins on biofilms grown in situ for 48 h in the absence......The extracellular matrix is a poorly studied, yet important component of dental biofilms. Fluorescence lectin-binding analysis (FLBA) is a powerful tool to characterize glycoconjugates in the biofilm matrix. This study aimed to systematically investigate the ability of 75 fluorescently labeled......-biofilms: Aleuria aurantia (AAL), Calystega sepiem (Calsepa), Lycopersicon esculentum (LEA), Morniga-G (MNA-G) and Helix pomatia (HPA). No significant correlation between the binding of specific lectins and bacterial composition was found. Fluorescently labeled lectins enable the visualization of glycoconjugates...

  5. The role of total-reflection x-ray fluorescence in atomic spectroscopy

    International Nuclear Information System (INIS)

    Toelg, G.; Klockenkaemper, R.

    1993-01-01

    Total-reflection X-ray fluorescence (TXRF) is a universal and economic method for the simultaneous determination of elements with atomic numbers > 11 down to the lower pg-level. It is a microanalytical tool for the analysis of small sample amounts placed on flat carriers and for contaminations on flat sample surfaces. Analyses of stratified near-surface layers are made possible by varying the incident angle of the primary beam in the region of total-reflection. This non-destructive method is especially suitable for thin layers of a few nanometres, deposited on wafer material although not usable as a microprobe method with a high lateral resolution. Furthermore, depth profiles of biological samples can be recorded by means of microtome sectioning of only a few micrometres, as, for example in the gradient analysis of human organs. In addition to micro- and surface-layer analysis, TXRF is effectively applied to element trace analysis. Homogeneous solutions, for example aqueous solutions, high-purity acids or body fluids, are pipetted onto carriers and, after evaporation, the dry residues are analyzed directly down to the pg/ml region. Particularly advantageous is the absence of matrix effects, so that an easy calibration can be carried out by adding a single internal standard element. A digestion or separation step preceding the actual determination becomes necessary if a more complex matrix is to be analysed or especially low detection limits have to be reached. A critical evaluation of the recent developments in atomic spectroscopy places TXRF in a leading position. Its outstanding features compete with those of e.g. electrothermal atomic absorption spectrometry (ETAAS), microwave induced plasma optical emission spectroscopy (MIP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) in the field of micro- and trace analysis and with Rutherford backscattering (RBS) and secondary ion mass spectrometry (SIMS) in the surface-layer analysis. (author)

  6. Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

    International Nuclear Information System (INIS)

    Anglos, D.; Nevin, A.

    2006-01-01

    Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to auto fluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

  7. A fluorescence spectroscopy study of traditional Chinese medicine Angelica

    Science.gov (United States)

    Zhao, Hongyan; Song, Feng; Liu, Shujing; Chen, Guiyang; Wei, Chen; Liu, Yanling; Liu, Jiadong

    2013-10-01

    By measuring the fluorescence spectra of Chinese medicine (CM) Angelica water solutions with different concentrations from 0.025 to 2.5 mg/mL, results showed that the fluorescence intensity was proportional to the concentration. Through fluorescence spectra of Angelica solution under different pH values, results indicated coumarin compounds were the active ingredients of Angelica. We also observed fluorescence quenching of the Angelica solution in the presence of spherical silver nanoparticles with radius of 12 nm. Keeping a certain value for the volume of the silver nanoparticles, the fluorescence intensity at 402 nm was linearly proportional to the Angelica in the range of 1-3 mg/mL.

  8. Laser resonant ionization spectroscopy and laser-induced resonant fluorescence spectra of samarium atom

    International Nuclear Information System (INIS)

    Jin, Changtai

    1995-01-01

    We have measured new high-lying levels of Sm atom by two-colour resonant photoionisation spectroscopy; we have observed the isotope shifts of Sm atom by laser-induced resonant fluorescence spectroscopy; the lifetime of eight low-lying levels of Sm atom were measured by using pulsed laser-Boxcar technique in atomic beam.

  9. Detection of mechanical and disease stresses in citrus plants by fluorescence spectroscopy

    Science.gov (United States)

    Belasque, J., Jr.; Gasparoto, M. C. G.; Marcassa, L. G.

    2008-04-01

    We have investigated the detection of mechanical and disease stresses in citrus plants (Citrus limonia [L.] Osbeck) using laser-induced fluorescence spectroscopy. Due to its economic importance we have chosen to investigate the citrus canker disease, which is caused by the Xanthomonas axonopodis pv. citri bacteria. Mechanical stress was also studied because it plays an important role in the plant's infection by such bacteria. A laser-induced fluorescence spectroscopy system, composed of a spectrometer and a 532 nm10 mW excitation laser was used to perform fluorescence spectroscopy. The ratio of two chlorophyll fluorescence bands allows us to detect and discriminate between mechanical and disease stresses. This ability to discriminate may have an important application in the field to detect citrus canker infected trees.

  10. Application of fluorescence spectroscopy and imaging in the detection of a photosensitizer in photodynamic therapy

    Science.gov (United States)

    Zang, Lixin; Zhao, Huimin; Zhang, Zhiguo; Cao, Wenwu

    2017-02-01

    Photodynamic therapy (PDT) is currently an advanced optical technology in medical applications. However, the application of PDT is limited by the detection of photosensitizers. This work focuses on the application of fluorescence spectroscopy and imaging in the detection of an effective photosenzitizer, hematoporphyrin monomethyl ether (HMME). Optical properties of HMME were measured and analyzed based on its absorption and fluorescence spectra. The production mechanism of its fluorescence emission was analyzed. The detection device for HMME based on fluorescence spectroscopy was designed. Ratiometric method was applied to eliminate the influence of intensity change of excitation sources, fluctuates of excitation sources and photo detectors, and background emissions. The detection limit of this device is 6 μg/L, and it was successfully applied to the diagnosis of the metabolism of HMME in the esophageal cancer cells. To overcome the limitation of the point measurement using fluorescence spectroscopy, a two-dimensional (2D) fluorescence imaging system was established. The algorithm of the 2D fluorescence imaging system is deduced according to the fluorescence ratiometric method using bandpass filters. The method of multiple pixel point addition (MPPA) was used to eliminate fluctuates of signals. Using the method of MPPA, SNR was improved by about 30 times. The detection limit of this imaging system is 1.9 μg/L. Our systems can be used in the detection of porphyrins to improve the PDT effect.

  11. Fluorescence spectroscopy of gastrointestinal tumors using δ-ALA

    Science.gov (United States)

    Borisova, E. G.; Vladimirov, B. G.; Angelov, I. G.; Avramov, L. A.

    2007-03-01

    In the recent study delta-aminolevulinic acid/Protoporphyrin IX (δ-ALA/PpIX) is used as fluorescent marker for dysplasia and tumor detection in esophagus and stomach. The δ-ALA is administered per os six hours before measurements at dose 20mg/kg weight. High-power light-emitting diode at 405 nm is used as an excitation source. Special opto-mechanical device is built to use the light guide of standard video-endoscopic system (Olimpus Corp.). Through endoscopic instrumental channel a fiber is applied to return information about fluorescence to microspectrometer (USB4000, OceanOptics Inc.). The fluorescence detected from tumor sites has very complex spectral origins. It consists of autofluorescence, fluorescence from exogenous fluorophores and re-absorption from the chromophores accumulated in the tissue investigated. Mucosa autofluorescence lies at 450-600 nm region. The fluorescence of PpIX is clearly pronounced at the 630-710 nm region. Deep minima in the tumor fluorescence signals are observed in the region 540-575 nm, related to hemoglobin re-absorption. Such high hemoglobin content is an indication of the tumors neovascularisation and it is clearly pronounced in all dysplastic and tumor sites investigated. The lack of fluorescence peaks in the red spectral area for normal mucosa is an indication for selective accumulation of δ-ALA/PpIX only in abnormal sites and gives high contrast when lesion borders are determined from clinicians during video observation in the process of diagnostic procedure. Very good correlation between fluorescence signals and histology examination results of the lesions investigated is achieved.

  12. Spectroscopy and nonclassical fluorescence properties of single trapped Ba+ ions

    International Nuclear Information System (INIS)

    Bolle, J.

    1998-06-01

    This thesis reports on the setup and application of an experimental apparatus for spectroscopic and quantum optical investigations of a single Barium ion in a Paul trap. The realization of the apparatus, which consists of the ion trap in ultra high vacuum, two laser systems, and a photon counting detection system, is described in detail, with particular consideration of the noise sources like stray light and laser frequency instabilities. The two lasers at 493 nm and 650 nm needed to continuously excite resonance fluorescence from the Barium ion have been realized using diode lasers only. The preparation of a single localized Barium ion is described, in particular its optical cooling with the laser light and the minimization of induced vibration in the trapping potential. The purely quantum mechanical property of antibunching is observed by measuring the intensity correlation function of resonance fluorescence from the trapped and cooled ion. Interference properties of the single ion resonance fluorescence are investigated with a Mach-Zehnder interferometer. From the measured high-contrast interference signal it is proven that each individual fluorescence photon interferes with itself. The fluorescence excitation spectrum, on varying one laser frequency, is also measured and exhibits dark resonances. These measurements are compared to calculations based on optical Bloch equations for the 8 atomic levels involved. Future experiments, in particular the detection of reduced quantum fluctuations (squeezing) in one quadrature component of the resonance fluorescence, are discussed. (author)

  13. Application of fluorescence spectroscopy for dissolved organic matter characterization in constructed wetlands

    Science.gov (United States)

    Sardana, A.; Aziz, T. N.; Cottrell, B. A.

    2017-12-01

    In this presentation we will discuss our ongoing work to characterize the photochemical behavior of dissolved organic matter (DOM) from wastewater treated in constructed wetlands. We have used a suite of spectroscopic and chromatographic techniques to characterize the DOM and to quantify the potential production of reactive oxygenated species (ROS). In the present study, DOM was fractionated based on its hydrophobicity and both the natural water isolates and fractionated DOM were characterized using SUVA254, spectral slope ratios, excitation emission matrix fluorescence spectroscopy (EEMs) and proton nuclear magnetic resonance (1H NMR). Photodegradation of wetland DOM and the formation of the hydroxyl radical (*OH), singlet oxygen (1O2), and the triplet-excited state (3DOM*) was also determined to assess the reactivity of DOM. EEM spectra exhibited the four main fluorescence peaks that are characteristic of DOM: peak A humic-like DOM, Peak C (fulvic or chromophoric DOM), Peak M (marine-like DOM), and peak T (tryptophan or protein-like absorbance). Two additional observed peaks with shorter emission wavelengths (A' Ex/Em = 243/278 nm and T' Ex/Em = 272/319 nm) were attributed to the microbial DOM in wastewater effluent. The spectral slope ratios decreased from 1.46 at the wetland inlet to 0.89 at the wetland outlet. The protein-like Peak T fluorescence decreased from 50% at the wetland inlet to 6.7% at the Wetland 2 outlet. A negative correlation between the percent fluorescence of Peak T and Peaks A, C and M confirmed the transition from the spectrum of pure wastewater with a primarily protein-like signature to a spectrum characteristic of terrestrially derived DOM. This transition coincided with enhanced formation rates and steady state concentrations of photochemically produced reactive intermediates (PPRIs). Size Exclusion Chromatography demonstrated that the influent wastewater had a lower molecular weight as compared to downstream wetland locations

  14. Evaluation of CDOM sources and their links with water quality in the lakes of Northeast China using fluorescence spectroscopy

    Science.gov (United States)

    Zhao, Ying; Song, Kaishan; Wen, Zhidan; Fang, Chong; Shang, Yingxin; Lv, Lili

    2017-07-01

    The spatial distributions of the fluorescence intensities Fmax for chromophoric dissolved organic matter (CDOM) components, the fluorescence indices (FI370 and FI310) and their correlations with water quality of 19 lakes in the Songhua River Basin (SHRB) across semiarid regions of Northeast China were examined with the data collected in September 2012 and 2015. The 19 lakes were divided into two groups according to EC (threshold value = 800 μS cm-1): fresh water (N = 13) and brackish water lakes (N = 6). The fluorescent characteristics of CDOM in the 19 lakes were investigated using excitation-emission matrix fluorescence spectroscopy (EEM) coupled with parallel factor (PARAFAC) and multivariate analysis. Two humic-like components (C1 and C3), one tryptophan-like component (C2), and one tyrosine-like component (C4) were identified by PARAFAC. The component C4 was not included in subsequent analyses due to the strong scatter in some colloidal water samples from brackish water lakes. The correlations between Fmax for the three EEM-PARAFAC extracted CDOM components C1-C3, the fluorescence indices (FI370 and FI310) and the water quality parameters (i.e., TN, TP, Chl-a, pH, EC, turbidity (Turb) and dissolved organic carbon (DOC)) were determined by redundancy analysis (RDA). The results of RDA analysis showed that spatial variation in land cover, pollution sources, and salinity/EC gradients in water quality affected Fmax for the fluorescent components C1-C3 and the fluorescence indices (FI370 and FI310). Further examination indicated that the CDOM fluorescent components and the fluorescence indices (FI370 and FI310) did not significantly differ (t-test, p > 0.05) in fresh water (N = 13) and brackish water lakes (N = 6). There was a difference in the distribution of the average Fmax for the CDOM fluorescent components between C1 to C3 from agricultural sources and urban wastewater sources in hypereutrophic brackish water lakes. The Fmax for humic-like components C1 and

  15. Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics

    Science.gov (United States)

    Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan

    2011-03-01

    We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

  16. Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Song, Wenjuan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong

    2013-01-01

    Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K a (×10 5 /M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K b (×10 4 /M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb

  17. Complexation of HSA with different forms of antimony (Sb): An application of fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Wenjuan [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Zhang, Daoyong [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Pan, Xiangliang, E-mail: xlpan@ms.xjb.ac.cn [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Lee, Duu-Jong [State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

    2013-04-15

    Antimony (Sb) pollution has been of a great environmental concern in some areas in China. Sb enters human body via drinking water, inhalation and food chain, unavoidably interacts with human serum albumin (HSA) in blood plasma, and consequently does harm to human health. The harmful effects of Sb on human health depend on the Sb species and their binding ability to HSA. In the present study, binding of three forms of Sb with HSA was investigated by excitation-emission matrix (EEM) spectroscopy. All of antimony potassium tartrate, antimony trichloride and potassium pyroantimonate quenched fluorescence of HSA. Values of conditional stability constant K{sub a} (×10{sup 5}/M) for Sb and HSA systems were 8.13–9.12 for antimony potassium tartrate, 2.51–4.27 for antimony trichloride and 3.63–9.77 for potassium pyroantimonate. The binding constant K{sub b} (×10{sup 4}/M) values of HSA with antimony potassium tartrate, antimony trichloride and potassium pyroantimonate were 0.02–0.07, 3.55–5.01, and 0.07–1.08, respectively. There was one independent class of binding site for antimony trichloride towards HSA. There was more than one Sb binding site and negative cooperativity between multiple binding sites for potassium pyroantimonate and antimony potassium tartrate towards HSA. The binding ability of HSA to complex Sb followed the order: antimony trichloride>potassium pyroantimonate>antimony potassium tartrate. -- Highlights: ► The first study reporting interaction of Sb with HSA. ► Sb can effectively quench the fluorescence of HSA. ► The binding ability of HSA to Sb was dependent on the form of Sb. ► Binding differences indicate differences in toxicity of various forms Sb to human. ► HAS-Sb binding parameters are important for understanding toxicity of Sb.

  18. Hybrid phosphorescence and fluorescence native spectroscopy for breast cancer detection.

    Science.gov (United States)

    Alimova, Alexandra; Katz, A; Sriramoju, Vidyasagar; Budansky, Yuri; Bykov, Alexei A; Zeylikovich, Roman; Alfano, R R

    2007-01-01

    Fluorescence and phosphorescence measurements are performed on normal and malignant ex vivo human breast tissues using UV LED and xenon lamp excitation. Tryptophan (trp) phosphorescence intensity is higher in both normal glandular and adipose tissue when compared to malignant tissue. An algorithm based on the ratio of trp fluorescence intensity at 345 nm to phosphorescence intensity at 500 nm is successfully used to separate normal from malignant tissue types. Normal specimens consistently exhibited a low I(345)I(500) ratio (15). The ratio analysis correlates well with histopathology. Intensity ratio maps with a spatial resolution of 0.5 mm are generated in which local regions of malignancy could be identified.

  19. Quantitative analysis of essential oils of Thymus daenensis using laser-induced fluorescence and Raman spectroscopy.

    Science.gov (United States)

    Khoshroo, H; Khadem, H; Bahreini, M; Tavassoli, S H; Hadian, J

    2015-11-10

    Laser-induced fluorescence and Raman spectroscopy are used for the investigation of different genotypes of Thymus daenensis native to the Ilam province of Iran. Different genotypes of T. daenensis essential oils, labeled T1 through T7, possess slight differences with regard to the composition of the thymol. The gas chromatography-mass spectrometry (GC-MS) method is performed to determine the concentration of each constituent as a reference method. The Raman spectra of different concentrations of pure thymol dissolved in hexane as standard samples are obtained via a laboratory prototype Raman spectroscopy setup for the calculation of the calibration curve. The regression coefficient and limit of detection are calculated. The possibility of the differentiation of different genotypes of T. daenensis is also examined by laser-induced fluorescence spectroscopy, although we do not know the exact amounts of their components. All the fluorescence spectral information is used jointly by cluster analysis to differentiate between 7 genotypes. Our results demonstrate the acceptable precision of Raman spectroscopy with GC-MS and corroborate the capacity of Raman spectroscopy in applications in the quantitative analysis field. Furthermore, the cluster analysis results show that laser-induced fluorescence spectroscopy is an acceptable technique for the rapid classification of different genotypes of T. daenensis without having any previous information of their exact amount of constituents. So, the ability to rapidly and nondestructively differentiate between genotypes makes it possible to efficiently select high-quality herbs from many samples.

  20. [Resolving excitation emission matrix spectroscopy of estuarine CDOM with parallel factor analysis and its application in organic pollution monitoring].

    Science.gov (United States)

    Guo, Wei-Dong; Huang, Jian-Ping; Hong, Hua-Sheng; Xu, Jing; Deng, Xun

    2010-06-01

    The distribution and estuarine behavior of fluorescent components of chromophoric dissolved organic matter (CDOM) from Jiulong Estuary were determined by fluorescence excitation emission matrix spectroscopy (EEMs) combined with parallel factor analysis (PARAFAC). The feasibility of these components as tracers for organic pollution in estuarine environments was also evaluated. Four separate fluorescent components were identified by PARAFAC, including three humic-like components (C1: 240, 310/382 nm; C2: 230, 250, 340/422 nm; C4: 260, 390/482 nm) and one protein-like components (C3: 225, 275/342 nm). These results indicated that UV humic-like peak A area designated by traditional "peak-picking method" was not a single peak but actually a combination of several fluorescent components, and it also had inherent links to so-called marine humic-like peak M or terrestrial humic-like peak C. Component C2 which include peak M decreased with increase of salinity in Jiulong Estuary, demonstrating that peak M can not be thought as the specific indicator of the "marine" humic-like component. Two humic-like components C1 and C2 showed additional behavior in the turbidity maximum region (salinity CDOM may provide a fast in-situ way to monitor the variation of the degree of organic pollution in estuarine environments.

  1. Analysis of Spectral Features of Seawaterbiooptical Components Fluorescence from the Excitation-emission Matrix

    Science.gov (United States)

    Salyuk, P. A.; Nagorny, I. G.

    The paper presents the method for processing of excitation-emission matrix of sea water and the allocation of the spectral characteristics of different types of colored dissolved organic matter (CDOM) and phytoplankton cells in seawater. The method consists of identification of regularly observed fluorescence peaks of CDOM in marine waters of different type and definition of the spectral ranges, where the predominant influence of these peaks are observed.

  2. Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy for Characterization of Dendritic Polymer Nanoparticles and Applications in Nanomedicine

    Directory of Open Access Journals (Sweden)

    Alexander Boreham

    2016-12-01

    Full Text Available The emerging field of nanomedicine provides new approaches for the diagnosis and treatment of diseases, for symptom relief and for monitoring of disease progression. One route of realizing this approach is through carefully constructed nanoparticles. Due to the small size inherent to the nanoparticles a proper characterization is not trivial. This review highlights the application of time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy (FLIM for the analysis of nanoparticles, covering aspects ranging from molecular properties to particle detection in tissue samples. The latter technique is particularly important as FLIM allows for distinguishing of target molecules from the autofluorescent background and, due to the environmental sensitivity of the fluorescence lifetime, also offers insights into the local environment of the nanoparticle or its interactions with other biomolecules. Thus, these techniques offer highly suitable tools in the fields of particle development, such as organic chemistry, and in the fields of particle application, such as in experimental dermatology or pharmaceutical research.

  3. Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy for Characterization of Dendritic Polymer Nanoparticles and Applications in Nanomedicine.

    Science.gov (United States)

    Boreham, Alexander; Brodwolf, Robert; Walker, Karolina; Haag, Rainer; Alexiev, Ulrike

    2016-12-24

    The emerging field of nanomedicine provides new approaches for the diagnosis and treatment of diseases, for symptom relief and for monitoring of disease progression. One route of realizing this approach is through carefully constructed nanoparticles. Due to the small size inherent to the nanoparticles a proper characterization is not trivial. This review highlights the application of time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy (FLIM) for the analysis of nanoparticles, covering aspects ranging from molecular properties to particle detection in tissue samples. The latter technique is particularly important as FLIM allows for distinguishing of target molecules from the autofluorescent background and, due to the environmental sensitivity of the fluorescence lifetime, also offers insights into the local environment of the nanoparticle or its interactions with other biomolecules. Thus, these techniques offer highly suitable tools in the fields of particle development, such as organic chemistry, and in the fields of particle application, such as in experimental dermatology or pharmaceutical research.

  4. Study of high density polyethylene under UV irradiation or mechanical stress by fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Douminge, L.

    2010-05-01

    Due to their diversity and their wide range of applications, polymers have emerged in our environment. For technical applications, these materials can be exposed to aggressive environment leading to an alteration of their properties. The effects of this degradation are linked to the concept of life duration, corresponding to the time required for a property to reach a threshold below which the material becomes unusable. Monitoring the ageing of polymer materials constitute a major challenge. Fluorescence spectroscopy is a technique able to provide accurate information concerning this issue. In this study, emphasis was placed on the use of fluorescence spectroscopy to study the phenomena involved in either the UV radiation or mechanical stresses of a polymer. In the case of high density polyethylene, the lack of intrinsic fluorescent signal leads to the use of a dye. This dye gives a fluorescent response depending on its microenvironment. All modifications in the macromolecular chain generate a shift of the fluorescent peak. This work can be dissociated in two major parts, on one hand the influence of UV aging on the fluorescent response and in another hand the influence of mechanical stresses. In the first part, complementary analyses like FTIR or DSC are used to correlate fluorescent results with known photo degradation mechanisms. The results show the great sensibility of the technique to the microstructural rearrangement in the polymer. In the second part, the dependence between the stress and the fluorescence emission gives opportunity to evaluate internal stresses in the material during cyclic solicitations. (author)

  5. X-ray emission spectroscopy. X-ray fluorescence

    International Nuclear Information System (INIS)

    Despujols, J.

    1992-01-01

    Principles of X-ray emission spectrometry are first recalled, then wave-length dispersive and energy dispersive X-ray fluorescence spectrometer are described. They are essentially designed for qualitative and quantitative analysis of elements (Z>10). Sample preparation, calibration, corrections, interferences, accuracy are reviewed. Examples of use in different industries are given. (71 refs.)

  6. Fluorescence spectroscopy of conformational changes of single LH2 complexes

    NARCIS (Netherlands)

    Rutkauskas, D.; Novoderezhkin, V.; Cogdell, R.J.; van Grondelle, R.

    2005-01-01

    We have investigated the energy landscape of the bacterial photosynthetic peripheral light-harvesting complex LH2 of purple bacterium Rhodopseudomonas acidophila by monitoring sequences of fluorescence spectra of single LH2 assemblies, at room temperature, with different excitation intensities as

  7. Fluorescence spectroscopy of Rhodamine 6G: concentration and solvent effects.

    Science.gov (United States)

    Zehentbauer, Florian M; Moretto, Claudia; Stephen, Ryan; Thevar, Thangavel; Gilchrist, John R; Pokrajac, Dubravka; Richard, Katherine L; Kiefer, Johannes

    2014-01-01

    Rhodamine 6G (R6G), also known as Rhodamine 590, is one of the most frequently used dyes for application in dye lasers and as a fluorescence tracer, e.g., in the area of environmental hydraulics. Knowing the spectroscopic characteristics of the optical emission is key to obtaining high conversion efficiency and measurement accuracy, respectively. In this work, solvent and concentration effects are studied. A series of eight different organic solvents (methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pentanol, acetone, and dimethyl sulfoxide (DMSO)) are investigated at constant dye concentration. Relatively small changes of the fluorescence spectrum are observed for the different solvents; the highest fluorescence intensity is observed for methanol and lowest for DMSO. The shortest peak wavelength is found in methanol (568 nm) and the longest in DMSO (579 nm). Concentration effects in aqueous R6G solutions are studied over the full concentration range from the solubility limit to highly dilute states. Changing the dye concentration provides tunability between ∼550 nm in the dilute case and ∼620 nm at high concentration, at which point the fluorescence spectrum indicates the formation of R6G aggregates. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Fluorescence relaxation spectroscopy : light on dynamical structures of flavoproteins

    NARCIS (Netherlands)

    Burten - Bastiaens, P.I.H.

    1992-01-01

    Refinements in technique and data analysis have opened new avenues for a detailed interpretation of protein fluorescence. What is more, by combining new insights in protein structure and dynamics with improved knowledge of photophysics of biological chromophores, the coupling between

  9. Limitations of fluorescence spectroscopy to characterize organic matter in engineered systems

    Science.gov (United States)

    Korak, J.

    2017-12-01

    Fluorescence spectroscopy has been widely used to characterize dissolved organic matter (DOM) in engineered systems, such as drinking water, municipal wastewater and industrial water treatment. While fluorescence data collected in water treatment applications has led to the development of strong empirical relationships between fluorescence responses and process performance, the use of fluorescence to infer changes in the underlying organic matter chemistry is often oversimplified and applied out of context. Fluorescence only measures a small fraction of DOM as fluorescence quantum yields are less than 5% for many DOM sources. Relying on fluorescence as a surrogate for DOM presence, character or reactivity may not be appropriate for systems where small molecular weight, hydrophilic constituents unlikely to fluoresce are important. In addition, some methods rely on interpreting fluorescence signals at different excitation wavelengths as a surrogate for operationally-defined humic- and fulvic-acids in lieu of traditional XAD fractionation techniques, but these approaches cannot be supported by other lines of evidence considering natural abundance and fluorescence quantum yields of these fractions. These approaches also conflict with parallel factor analysis (PARAFAC), a statistical approach that routinely identifies fluorescence components with dual excitation behavior. Lastly, methods developed for natural systems are often applied out of context to engineered systems. Fluorescence signals characteristic of phenols or indoles are often interpreted as indicators for biological activity in natural systems due to fluorescent amino acids and peptides, but this interpretation is may not be appropriate in engineering applications where non-biological sources of phenolic functional groups may be present. This presentation explores common fluorescence interpretation approaches, discusses the limitations and provides recommendations related to engineered systems.

  10. Quantitative frequency-domain fluorescence spectroscopy in tissues and tissue-like media

    Science.gov (United States)

    Cerussi, Albert Edward

    1999-09-01

    In the never-ending quest for improved medical technology at lower cost, modern near-infrared optical spectroscopy offers the possibility of inexpensive technology for quantitative and non-invasive diagnoses. Hemoglobin is the dominant chromophore in the 700-900 nm spectral region and as such it allows for the optical assessment of hemoglobin concentration and tissue oxygenation by absorption spectroscopy. However, there are many other important physiologically relevant compounds or physiological states that cannot be effectively sensed via optical methods because of poor optical contrast. In such cases, contrast enhancements are required. Fluorescence spectroscopy is an attractive component of optical tissue spectroscopy. Exogenous fluorophores, as well as some endogenous ones, may furnish the desperately needed sensitivity and specificity that is lacking in near-infrared optical tissue spectroscopy. The main focus of this thesis was to investigate the generation and propagation of fluorescence photons inside tissues and tissue-like media (i.e., scattering dominated media). The standard concepts of fluorescence spectroscopy have been incorporated into a diffusion-based picture that is sometimes referred to as photon migration. The novelty of this work lies in the successful quantitative recovery of fluorescence lifetimes, absolute fluorescence quantum yields, fluorophore concentrations, emission spectra, and both scattering and absorption coefficients at the emission wavelength from a tissue-like medium. All of these parameters are sensitive to the fluorophore local environment and hence are indicators of the tissue's physiological state. One application demonstrating the capabilities of frequency-domain lifetime spectroscopy in tissue-like media is a study of the binding of ethidium bromide to bovine leukocytes in fresh milk. Ethidium bromide is a fluorescent dye that is commonly used to label DNA, and hence visualize chromosomes in cells. The lifetime of

  11. Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues

    Science.gov (United States)

    Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

    2017-12-01

    Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics.

  12. Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues.

    Science.gov (United States)

    Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

    2017-10-01

    Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  13. Integrated optical measurement system for fluorescence spectroscopy in microfluidic channels

    DEFF Research Database (Denmark)

    Hübner, Jörg; Mogensen, Klaus Bo; Jørgensen, Anders Michael

    2001-01-01

    A transportable miniaturized fiber-pigtailed measurement system is presented which allows quantitative fluorescence detection in microliquid handling systems. The microliquid handling chips are made in silica on silicon technology and the optical functionality is monolithically integrated with th...... with two dyes, fluorescein, and Bodipy 650/665 X, showed good linear behavior over a wide range of concentrations. Minimally detected concentrations were 250 pM for fluorescein and 100 nM for Bodipy....

  14. Lipid diffusion in planar membranes investigated by fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Hof, Martin

    2010-01-01

    Roč. 1798, č. 7 (2010), s. 1377-1391 ISSN 0005-2736 R&D Projects: GA ČR GA203/08/0114; GA AV ČR GEMEM/09/E006 Institutional research plan: CEZ:AV0Z40400503 Keywords : supported lipid bilayer * giant unilamellar vesicle * fluorescence recovery after photobleaching Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.647, year: 2010

  15. International conference on matrix isolation spectroscopy. Extended Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-01

    Seventy-five extended abstracts are arranged under the following headings: generation of reactive species and their isolation in matrices, spectra of metal atoms and cluster formation, stable molecules in matrices, Raman- and IR-spectroscopy, high-temperature molecules, reactive matrices, relaxation phenomena studied in matrices, and physical properties of matrices. (DLC)

  16. Impurity studies in fusion devices using laser-fluorescence-spectroscopy

    International Nuclear Information System (INIS)

    Husinsky, W.R.

    1980-08-01

    Resonance fluorescence excitation of neutral atoms using tunable radiation from dye lasers offers a number of unique advantages for impurity studies in fusion devices. Using this technique, it is possible to perform local, time-resolved measurements of the densities and velocity distributions of metallic impurities in fusion devices without disturbing the plasma. Velocities are measured by monitoring the fluorescence intensity while tuning narrow bandwidth laser radiation through the Doppler - broadened absorbtion spectrum of the transition. The knowledge of the velocity distribution of neutral impurities is particularly useful for the determination of impurity introduction mechanisms. The laser fluorescence technique will be described in terms of its application to metallic impurities in fusion devices and related laboratory experiments. Particular attention will be given to recent results from the ISX-B tokamak using pulsed dye lasers where detection sensitivities for neutral Fe of 10 6 atoms/cm 3 with a velocity resolution of 600 m/sec (0.1 eV) have been achieved. Techniques for exciting plasma particles (H,D) will also be discussed

  17. Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

    Directory of Open Access Journals (Sweden)

    M. Z. Bieroza

    2010-04-01

    Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

  18. Very High Spectral Resolution Imaging Spectroscopy: the Fluorescence Explorer (FLEX) Mission

    Science.gov (United States)

    Moreno, Jose F.; Goulas, Yves; Huth, Andreas; Middleton, Elizabeth; Miglietta, Franco; Mohammed, Gina; Nedbal, Ladislav; Rascher, Uwe; Verhoef, Wouter; Drusch, Matthias

    2016-01-01

    The Fluorescence Explorer (FLEX) mission has been recently selected as the 8th Earth Explorer by the European Space Agency (ESA). It will be the first mission specifically designed to measure from space vegetation fluorescence emission, by making use of very high spectral resolution imaging spectroscopy techniques. Vegetation fluorescence is the best proxy to actual vegetation photosynthesis which can be measurable from space, allowing an improved quantification of vegetation carbon assimilation and vegetation stress conditions, thus having key relevance for global mapping of ecosystems dynamics and aspects related with agricultural production and food security. The FLEX mission carries the FLORIS spectrometer, with a spectral resolution in the range of 0.3 nm, and is designed to fly in tandem with Copernicus Sentinel-3, in order to provide all the necessary spectral / angular information to disentangle emitted fluorescence from reflected radiance, and to allow proper interpretation of the observed fluorescence spatial and temporal dynamics.

  19. In vivo study of the human skin by the method of laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Borisova, E.; Avramov, L.

    2000-01-01

    The goals of this study are to perform a preliminary evaluation of the diagnostic potential of noninvasive laser-induced auto-fluorescence spectroscopy (LIAFS) for human skin and optimize of detection and diagnosis of hollow organs and skin. In recent years, there has been growing interest in the use of laser-induced fluorescence to discriminate disease from normal surrounding tissue. The most fluorescence studies have used exogenous fluorophores of this discrimination. The laser-induced auto-fluorescence which is used for diagnosis of tissues in the human body avoids administration of any drugs. In this study a technique for optical biopsy of in vivo human skin is presented. The auto-fluorescence characterization of tissue relies on different spectral properties of tissues. It was demonstrated a differentiation between normal skin and skin with vitiligo. Two main endogenous fluorophores in the human skin account for most of the cellular auto-fluorescence for excitation wavelength 337 nm reduced from of nicotinamide adenine dinucleotide and collagen. The auto-fluorescence spectrum of human skin depend on main internal absorbers which are blood and melanin. In this study was described the effect caused by blood and melanin content on the shape of the auto-fluorescence spectrum of human skin. Human skin fluorescence spectrum might provide dermatologists with important information and such investigations are successfully used now in skin disease diagnostics, in investigation of the environmental factor impact or for evaluation of treatment efficiency. (authors)

  20. Investigation of matrix-isolated species: spectroscopy and molecular modelling

    International Nuclear Information System (INIS)

    Nemukhin, A V; Grigorenko, B L; Bochenkova, A V; Khriachtchev, L Yu; Raesaenen, M

    2007-01-01

    The results of experimental and theoretical approaches to the study of some stable and unstable chemical species in low-temperature noble gas matrices are considered. The characteristic features of matrix effects manifested in the spectra of the SH radicals in krypton matrices are discussed. The structure and the spectra of HArF in argon matrices and the structure and dynamics of the intermolecular complexes HXeOH with water are analysed.

  1. Effect of the sample matrix on measurement uncertainty in X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Morgenstern, P.; Brueggemann, L.; Wennrich, R.

    2005-01-01

    The estimation of measurement uncertainty, with reference to univariate calibration functions, is discussed in detail in the Eurachem Guide 'Quantifying Uncertainty in Analytical Measurement'. The adoption of these recommendations to quantitative X-ray fluorescence analysis (XRF) involves basic problems which are above all due to the strong influence of the sample matrix on the analytical response. In XRF-analysis, the proposed recommendations are consequently applicable only to the matrix corrected response. The application is also restricted with regard to both the matrices and analyte concentrations. In this context the present studies are aimed at the problems to predict measurement uncertainty also with reference to more variable sample compositions. The corresponding investigations are focused on the use of the intensity of the Compton scattered tube line as an internal standard to assess the effect of the individual sample matrix on the analytical response relatively to a reference matrix. Based on this concept the estimation of the measurement uncertainty of an analyte presented in an unknown specimen can be predicted in consideration of the data obtained under defined matrix conditions

  2. Fluorescence spectroscopy for throat cancer detection using human saliva

    Science.gov (United States)

    Kumar, Pavan; Singh, Ashutosh; Zaffar, Mohammad; Pradhan, Asima

    2018-02-01

    Throat precancer detection using fluorescence from human saliva is reported here. It may be noted that accessing the throat for investigation is cumbersome and use of saliva as a diagnostic medium may ease the process. The study has been conducted on three groups of patients: oral squamous cell carcinoma (OSCC), dysplasia, and normal (control). An in-house developed compact set-up has been used for fluorescence measurements. The compact system consist of a 375 nm laser diode, collimating lens, long pass filter, fibers, and cuvette holder. Major and minor bands of flavin adenine dinucleotide (FAD) and porphyrin are observed in the spectra. A receiver operating characteristic (ROC) analysis has been used to evaluate the diagnostic performance. Area under the spectra has been chosen for discrimination among the groups and is able to differentiate OSCC to normal, dysplasia to normal, and OSCC to dysplasia with sensitivities 100% (48/48), 92% (32/35), 77% (37/48), and specificities 96% (50/52), 96% (50/52), 89% (31/35) with the accuracy of 98%, 94% and 82% respectively. Sensitivity and specificity, when differentiating OSCC to normal and dysplasia to normal, are significantly large, which indicates that human saliva may be an excellent diagnostic medium for early detection of throat cancer.

  3. A Pyrene- and Phosphonate-Containing Fluorescent Probe as Guest Molecule in a Host Polymer Matrix

    Directory of Open Access Journals (Sweden)

    Jacqueline Marchand-Brynaert

    2013-02-01

    Full Text Available New host-guest materials have been prepared by incorporation of a home-made organic probe displaying a pyrene motif and a phosphonate function into a regular amphiphilic copolymer. Using powder X-Ray diffraction, photoluminescence and FT-IR spectroscopy, we have been able to study the non-covalent interactions between the host matrix and the guest molecule in the solid state. Interestingly, we have shown that the matrix directs the guest spatial localization and alters its properties. Thanks to the comparison of pyrene vs. N-pyrenylmaleimide derivatives, the influence of the chemical nature of the guest molecules on the non-covalent interactions with the host have been studied. In addition, using polyethylene glycol as a reference host, we have been able to evidence a true matrix effect within our new insertion materials. The phosphonated guest molecule appears to be a novel probe targeting the hydrophilic domain of the host copolymer.

  4. Detection of Water Contamination Events Using Fluorescence Spectroscopy and Alternating Trilinear Decomposition Algorithm

    Directory of Open Access Journals (Sweden)

    Jie Yu

    2017-01-01

    Full Text Available The method based on conventional index and UV-vision has been widely applied in the field of water quality abnormality detection. This paper presents a qualitative analysis approach to detect the water contamination events with unknown pollutants. Fluorescence spectra were used as water quality monitoring tools, and the detection method of unknown contaminants in water based on alternating trilinear decomposition (ATLD is proposed to analyze the excitation and emission spectra of the samples. The Delaunay triangulation interpolation method was used to make the pretreatment of three-dimensional fluorescence spectra data, in order to estimate the effect of Rayleigh and Raman scattering; ATLD model was applied to establish the model of normal water sample, and the residual matrix was obtained by subtracting the measured matrix from the model matrix; the residual sum of squares obtained from the residual matrix and threshold was used to make qualitative discrimination of test samples and distinguish drinking water samples and organic pollutant samples. The results of the study indicate that ATLD modeling with three-dimensional fluorescence spectra can provide a tool for detecting unknown organic pollutants in water qualitatively. The method based on fluorescence spectra can be complementary to the method based on conventional index and UV-vision.

  5. 2D fluorescence spectroscopy for monitoring ion-exchange membrane based technologies - Reverse electrodialysis (RED).

    Science.gov (United States)

    Pawlowski, Sylwin; Galinha, Claudia F; Crespo, João G; Velizarov, Svetlozar

    2016-01-01

    Reverse electrodialysis (RED) is one of the emerging, membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operation constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detection is one of the main challenges for successful RED technology implementation. In the present study, two-dimensional (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitation-emission matrices (EEMs) of ion-exchange membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operation. Fouling evolvement on the ion-exchange membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). Additionally, the efficiency of cleaning strategy was assessed by measuring the membrane fluorescence emission intensity before and after cleaning. The anion-exchange membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and membrane cleaning efficiency in ion exchange membrane processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Time-Gated Raman Spectroscopy for Quantitative Determination of Solid-State Forms of Fluorescent Pharmaceuticals.

    Science.gov (United States)

    Lipiäinen, Tiina; Pessi, Jenni; Movahedi, Parisa; Koivistoinen, Juha; Kurki, Lauri; Tenhunen, Mari; Yliruusi, Jouko; Juppo, Anne M; Heikkonen, Jukka; Pahikkala, Tapio; Strachan, Clare J

    2018-04-03

    Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals. Time-gated Raman spectroscopy with a 128 × (2) × 4 CMOS SPAD detector was applied for quantitative analysis of ternary mixtures of solid-state forms of the model drug, piroxicam (PRX). Partial least-squares (PLS) regression allowed quantification, with Raman-active time domain selection (based on visual inspection) improving performance. Model performance was further improved by using kernel-based regularized least-squares (RLS) regression with greedy feature selection in which the data use in both the Raman shift and time dimensions was statistically optimized. Overall, time-gated Raman spectroscopy, especially with optimized data analysis in both the spectral and time dimensions, shows potential for sensitive and relatively routine quantitative analysis of photoluminescent pharmaceuticals during drug development and manufacturing.

  7. Macromolecule biosynthesis assay and fluorescence spectroscopy methods to explore antimicrobial peptide mode(s) of action

    DEFF Research Database (Denmark)

    Jana, Bimal; Baker, Kristin Renee; Guardabassi, Luca

    2017-01-01

    the biosynthesis rate of macromolecules (e.g., DNA, RNA, protein, and cell wall) and the cytoplasmic membrane proton motive force (PMF) energy can help to unravel the diverse modes of action of AMPs. Here, we present an overview of macromolecule biosynthesis rate measurement and fluorescence spectroscopy methods...

  8. Study of the interaction of Tb (III) with dextran through fluorescence spectroscopy and optical rotatory dispersion

    International Nuclear Information System (INIS)

    Vasconcelos, Sandra S.; Rodrigues, J.F.

    1984-01-01

    A study of the interaction of Tb(III) with dextran in aqueous solution was perform using fluorescence spectroscopy and optical rotatory dispersion. The results indicate the formation of a complex with the displacent of water from the cation coordinated sphere by hydroxyl groups at the second and third carbon atoms of the monomer unit. (Author) [pt

  9. Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shear, Trevor A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-16

    This literature review will focus on both laboratory and synchrotron based X-ray tomography of materials and highlight the inner workings of these instruments. X-ray fluorescence spectroscopy will also be reviewed and applications of the tandem use of these techniques will be explored. The real world application of these techniques during the internship will also be discussed.

  10. Fluorescence spectral correlation spectroscopy (FSCS) for probes with highly overlapping emission spectra

    Czech Academy of Sciences Publication Activity Database

    Benda, A.; Kapusta, Peter; Hof, Martin; Gaus, K.

    2014-01-01

    Roč. 22, č. 3 (2014), s. 2973-2988 ISSN 1094-4087 R&D Projects: GA AV ČR KJB400400904; GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : spectroscopy * fluorescence and luminiscence * confocal microscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.488, year: 2014

  11. Fluorescence spectroscopy: a tool to characterize humic substances in soil colonized by microorganisms?

    Czech Academy of Sciences Publication Activity Database

    Řezáčová, Veronika; Gryndler, Milan

    2006-01-01

    Roč. 51, č. 3 (2006), s. 215-221 ISSN 0015-5632 R&D Projects: GA ČR GA526/03/0188 Institutional research plan: CEZ:AV0Z50200510 Keywords : fluorescence spectroscopy * humic substances * microorganism Subject RIV: EE - Microbiology, Virology Impact factor: 0.963, year: 2006

  12. A statistical strategy to assess cleaning level of surfaces using fluorescence spectroscopy and Wilks’ ratio

    DEFF Research Database (Denmark)

    Stoica, Iuliana-Madalina; Babamoradi, Hamid; van den Berg, Frans

    2017-01-01

    •A statistical strategy combining fluorescence spectroscopy, multivariate analysis and Wilks’ ratio is proposed.•The method was tested both off-line and on-line having riboflavin as a (controlled) contaminant.•Wilks’ ratio signals unusual recordings based on shifts in variance and covariance...... structure described in in-control data....

  13. Speciation of actinides in aqueous solution by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    International Nuclear Information System (INIS)

    Kimura, Takaumi; Kato, Yoshiharu; Meinrath, G.; Yoshida, Zenko; Choppin, G.R.

    1995-01-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) as a sensitive and selective method has been applied to the speciation of actinides in aqueous solution. Studies on hydrolysis and carbonate complexation of U(VI) and on determination of hydration number of Cm(III) are reported. (author)

  14. Method for rapid multidiameter single-fiber reflectance and fluorescence spectroscopy through a fiber bundle

    NARCIS (Netherlands)

    Amelink, A.; Hoy, C.L.; Gamm, U.A.; Sterenborg, H.J.C.M.; Robinson, D.J.

    2014-01-01

    We have recently demonstrated a means for quantifying the absorption and scattering properties of biological tissue through multidiameter single-fiber reflectance (MDSFR) spectroscopy. These measurements can be used to correct single-fiber fluorescence (SFF) spectra for the influence of optical

  15. Bilayer Localization of Membrane-Active Peptides Studied in Biomimetic Vesicles by Visible and Fluorescence Spectroscopies

    Czech Academy of Sciences Publication Activity Database

    Sheynis, T.; Sýkora, Jan; Benda, Aleš; Kolusheva, S.; Hof, Martin; Jelinek, R.

    2003-01-01

    Roč. 270, č. 22 (2003), s. 4478-4487 ISSN 0014-2956 R&D Projects: GA MŠk LN00A032 Institutional research plan: CEZ:AV0Z4040901 Keywords : solvent relaxation * fluorescence correlation spectroscopy * lipid bilayers Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.001, year: 2003

  16. Biological Interaction of Molybdenocene Dichloride with Bovine Serum Albumin Using Fluorescence Spectroscopy

    Science.gov (United States)

    Domínguez, Moralba; Cortes-Figueroa, Jose´ E.; Meléndez, Enrique

    2018-01-01

    Bioinorganic topics are ubiquitous in the inorganic chemistry curriculum; however, experiments to enhance understanding of related topics are scarce. In this proposed laboratory, upper undergraduate students assess the biological interaction of molybdenocene dichloride (Cp2MoCl2) with bovine serum albumin (BSA) by fluorescence spectroscopy.…

  17. Ultratrace analysis of actinides via coprecipitation/laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Miller, S.M.

    1982-01-01

    Actinides were selectively preconcentrated by coprecipitating each out of solution with a fluoride matrix and calcining each sample at 800 0 C. The fluorescence spectrum of each sample was recorded by illuminating the sample with laser light and detecting fluorescence with either a fluorescence/Raman spectrometer, an infrared spectrometer or in certain cases a filter fluorimeter. Three previously unobserved actinide spectra were recorded. Narrow lines at 546.9 nm, 564.6 nm, and 569.6 nm were found for CaF 2 :PuO 2++ at 10K. CaF 2 :Am + 3 displayed two broadband fluorescent peaks at 625 nm and 746 nm at room temperature and CaF 2 :Pu + 3 possessed a fluorescent peak at 1.22 microns at 10K. Energy transfer was observed in the form of Tb fluorescence quenching in TbF 3 :Pu + 3 when Pu was present in quantities of 10 ppM or more and in the form of Tb fluorescence enhancement in TbF 3 :Am + 3 when 1 ppM or more of Am was present. Careful sample preparation and the use of temporal as well as a spectral discrimination system extended the detection limit of U from 1 ml samples to the subfemtogram level. The fluorescence detection limits for Pu and Am were extended to 0.48 and 0.032 pg/ml. 39 figures, 9 tables

  18. Solvent induced fluorescence enhancement of graphene oxide studied by ultrafast spectroscopy

    Science.gov (United States)

    Zhao, Litao; Chen, Jinquan; He, Xiaoxiao; Yu, Xiantong; Yan, Shujun; Zhang, Sanjun; Pan, Haifeng; Xu, Jianhua

    2018-05-01

    Femtosecond transient absorption (TA) spectroscopy combined with picosecond time resolved fluorescence (TRF) were used to reveal the fluorescence kinetics of graphene oxide (GO) in water, ethanol and water-ethanol mixtures. Size-independent fluorescence of GO were observed in water, and pH-dependent fluorescence spectra could be fitted well by a triple emission relaxation with peaks around 440 nm, 500 nm, and 590 nm respectively. The results indicate that polycyclic aromatic hydrocarbons (PAHs) linked by oxygen-containing functional groups dominate GO's fluorescence emission. GO's fluorescence quantum yield was measured to be 2.8% in ethanol but 1.2% in water. The three decay components fluorescence decay, as well as the transient absorption dynamics with an offset, confirmed this solvent induced fluorescence enhancement. GO's Raman spectral signals showed that GO in ethanol has a smaller average size of PAHs than that of GO in water. Therefore, besides other enhancement effects reported in literatures, we proposed that solvents could also change the size of PAHs, resulting in a photoluminescence enhancement. Our experimental data demonstrates that GO's quantum yield could be up to 2.8% in water and 8.4% in ethanol and this observation may help ones to improve GO's photoluminescence efficiency as well as its applications in solution.

  19. Fluorescence kinetics of Trp-Trp dipeptide and its derivatives in water via ultrafast fluorescence spectroscopy.

    Science.gov (United States)

    Jia, Menghui; Yi, Hua; Chang, Mengfang; Cao, Xiaodan; Li, Lei; Zhou, Zhongneng; Pan, Haifeng; Chen, Yan; Zhang, Sanjun; Xu, Jianhua

    2015-08-01

    Ultrafast fluorescence dynamics of Tryptophan-Tryptophan (Trp-Trp/Trp2) dipeptide and its derivatives in water have been investigated using a picosecond resolved time correlated single photon counting (TCSPC) apparatus together with a femtosecond resolved upconversion spectrophotofluorometer. The fluorescence decay profiles at multiple wavelengths were fitted by a global analysis technique. Nanosecond fluorescence kinetics of Trp2, N-tert-butyl carbonyl oxygen-N'-aldehyde group-l-tryptophan-l-tryptophan (NBTrp2), l-tryptophan-l-tryptophan methyl ester (Trp2Me), and N-acetyl-l-tryptophan-l-tryptophan methyl ester (NATrp2Me) exhibit multi-exponential decays with the average lifetimes of 1.99, 3.04, 0.72 and 1.22ns, respectively. Due to the intramolecular interaction between two Trp residues, the "water relaxation" lifetime was observed around 4ps, and it is noticed that Trp2 and its derivatives also exhibit a new decay with a lifetime of ∼100ps, while single-Trp fluorescence decay in dipeptides/proteins shows 20-30ps. The intramolecular interaction lifetime constants of Trp2, NBTrp2, Trp2Me and NATrp2Me were then calculated to be 3.64, 0.93, 11.52 and 2.40ns, respectively. Candidate mechanisms (including heterogeneity, solvent relaxation, quasi static self-quenching or ET/PT quenching) have been discussed. Copyright © 2015. Published by Elsevier B.V.

  20. Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

    Science.gov (United States)

    Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

    2017-10-30

    Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

  1. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

    2015-01-01

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

  2. Reactions of laser ablated uranium with nitrogen studied using matrix isolation spectroscopy

    International Nuclear Information System (INIS)

    Sankaran, K.; Sundararajan, K.; Viswanathan, K.S.

    1999-01-01

    Unusual reactions were found to occur when uranium was laser ablated in the presence of nitrogen. The reaction products were trapped in a rigid inert gas matrix and studied using infrared spectroscopy. The species formed were strongly dependent on the partial pressure of nitrogen in the matrix gas used during the ablation process; at low nitrogen partial pressures uranium dinitride (NUN) was the major reaction product, while at high partial pressures of nitrogen the mononitride, UN, was the predominant product. (author)

  3. On-Line Monitoring of Fermentation Processes by Near Infrared and Fluorescence Spectroscopy

    DEFF Research Database (Denmark)

    Svendsen, Carina

    Monitoring and control of fermentation processes is important to ensure high product yield, product quality and product consistency. More knowledge on on-line analytical techniques such as near infrared and fluorescence spectroscopy is desired in the fermentation industry to increase the efficiency...... of on-line monitoring systems. The primary aim of this thesis is to elucidate and explore the dynamics in fermentation processes by spectroscopy. Though a number of successful on-line lab-scale monitoring systems have been reported, it seems that several challenges are still met, which limits the number...... of full-scale systems implemented in industrial fermentation processes. This thesis seeks to achieve a better understanding of the techniques near infrared and fluorescence spectroscopy and thereby to solve some of the challenges that are encountered. The thesis shows the advantages of applying real...

  4. Feasibility of Raman spectroscopy in vitro after 5-ALA-based fluorescence diagnosis in the bladder

    Science.gov (United States)

    Grimbergen, M. C. M.; van Swol, C. F. P.; van Moorselaar, R. J. A.; Mahadevan-Jansen, A.,; Stone, N.

    2006-02-01

    Photodynamic diagnosis (PDD) has become popular in bladder cancer detection. Several studies have however shown an increased false positive biopsies rate under PDD guidance compared to conventional cystoscopy. Raman spectroscopy is an optical technique that utilizes molecular specific, inelastic scattering of light photons to interrogate biological tissues, which can successfully differentiate epithelial neoplasia from normal tissue and inflammations in vitro. This investigation was performed to show the feasibility of NIR Raman spectroscopy in vitro on biopsies obtained under guidance of 5-ALA induced PPIX fluorescence imaging. Raman spectra of a PPIX solution was measured to obtain a characteristic signature for the photosensitzer without contributions from tissue constituents. Biopsies were obtained from patients with known bladder cancer instilled with 50ml, 5mg 5-ALA two hours prior to trans-urethral resection of tumor (TURT). Additional biopsies were obtained at a fluorescent and non-fluorescent area, snap-frozen in liquid nitrogen and stored at -80 °C. Each biopsy was thawed before measurements (10sec integration time) with a confocal Raman system (Renishaw Gloucestershire, UK). The 830 nm excitation (300mW) source is focused on the tissue by a 20X ultra-long-working-distance objective. Differences in fluorescence background between the two groups were removed by means of a special developed fluorescence subtraction algorithm. Raman spectra from ALA biopsies showed different fluorescence background which can be effectively removed by a fluorescence subtraction algorithm. This investigation shows that the interaction of the ALA induced PPIX with Raman spectroscopy in bladder samples. Combination of these techniques in-vivo may lead to a viable method of optical biopsies in bladder cancer detection.

  5. Elimination of matrix effect in quantitative analysis of elements using x-ray fluorescence

    International Nuclear Information System (INIS)

    Sampaio, R.V.

    1973-07-01

    The emission-transmission method of Leroux and Mahmud, an experimental technique for compensating matrix effects in photon excited X-ray fluorescence analysis, was used to determine the concentration of lead and antimony in pellets of galalith. The effect of interfering elements was studied by adding various concentrations of mercury and tin to the respective pellets. To illustrate possible environmental applications, a number of pellets was prepared from leaves of almond trees located in different regions of Rio de Janeiro. Lead concentrations were determined for the dried leaf material and showed values ranging from 50 to 145 parts per million [pt

  6. Interaction of Chelerythrine with Keyhole Limpet Hemocyanin: a Fluorescence Spectroscopy and Molecular Docking Study

    Science.gov (United States)

    Zhong, M.; Long, R. Q.; Wang, Y. H.; Chen, C. L.

    2018-05-01

    The quenching mechanism between chelerythrine (CHE) and keyhole limpet hemocyanin (KLH) was investigated using fluorescence spectroscopy and molecular docking. The experiments were conducted at three different temperatures (293, 298, and 303 K). The results revealed that the intrinsic fluorescence of KLH was strongly quenched by CHE through a static quenching mechanism. The thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction were calculated, indicating that the interaction between CHE and KLH was spontaneous and that van der Waals forces and hydrogen bond formation played major roles in the binding process. The intrinsic fluorescence of the tyrosine and tryptophan residues in KLH was studied by synchronous fluorescence, which suggested that CHE changed the conformation of KLH. Finally, molecular docking was used to obtain detailed information on the binding sites and binding affinities between CHE and KLH.

  7. Front-face fluorescence spectroscopy study of globular proteins in emulsions: influence of droplet flocculation.

    Science.gov (United States)

    Rampon, V; Genot, C; Riaublanc, A; Anton, M; Axelos, M A V; McClements, D J

    2003-04-23

    Measurement of the intensity (I(MAX)) and/or wavelength (lambda(MAX)) of the maximum in the tryptophan (TRP) emission spectrum using front-face fluorescence spectroscopy (FFFS) can be used to provide information about the molecular environment of proteins in nondiluted emulsions. Many protein-stabilized emulsions in the food industry are flocculated, and therefore, we examined the influence of droplet flocculation on FFFS. Stock oil-in-water emulsions stabilized by bovine serum albumin were prepared by high-pressure valve homogenization (30 wt % n-hexadecane, 0.35 wt % BSA, pH 7). These emulsions were used to create model systems with different degrees of droplet flocculation, either by changing the pH, adding surfactant, or adding xanthan. Emulsions (21 wt % n-hexadecane, 0.22 wt % BSA) with different pH (5 and 7) and molar ratios of Tween 20 to BSA (R = 0-131) were prepared by dilution of the stock emulsion. As the surfactant concentration was increased, the protein was displaced from the droplet surfaces, which caused an increase in both I(MAX) and lambda(MAX), because of the change in TRP environment. The dependence of I(MAX) and lambda(MAX) on surfactant concentration followed a similar pattern in emulsions that were initially flocculated (pH 5) and nonflocculated (pH 7). Relatively small changes in FFFS emission spectra were observed in emulsions (21 wt % n-hexadecane, 0.22 wt % BSA, pH 7) with different levels of depletion flocculation induced by adding xanthan. These results suggested that droplet flocculation did not have a major impact on FFFS. This study shows that FFFS is a powerful technique for nondestructively providing information about the molecular environment of proteins in concentrated and flocculated protein-stabilized emulsions. Nevertheless, in general the suitability of the technique may also depend on protein type and the nature of the physicochemical matrix surrounding the proteins.

  8. Rapid screening test for porphyria diagnosis using fluorescence spectroscopy

    Science.gov (United States)

    Lang, A.; Stepp, H.; Homann, C.; Hennig, G.; Brittenham, G. M.; Vogeser, M.

    2015-07-01

    Porphyrias are rare genetic metabolic disorders, which result from deficiencies of enzymes in the heme biosynthesis pathway. Depending on the enzyme defect, different types of porphyrins and heme precursors accumulate for the different porphyria diseases in erythrocytes, liver, blood plasma, urine and stool. Patients with acute hepatic porphyrias can suffer from acute neuropathic attacks, which can lead to death when undiagnosed, but show only unspecific clinical symptoms such as abdominal pain. Therefore, in addition to chromatographic methods, a rapid screening test is required to allow for immediate identification and treatment of these patients. In this study, fluorescence spectroscopic measurements were conducted on blood plasma and phantom material, mimicking the composition of blood plasma of porphyria patients. Hydrochloric acid was used to differentiate the occurring porphyrins (uroporphyrin-III and coproporphyrin-III) spectroscopically despite their initially overlapping excitation spectra. Plasma phantom mixtures were measured using dual wavelength excitation and the corresponding concentrations of uroporphyrin-III and coproporphyrin-III were determined. Additionally, three plasma samples of porphyria patients were examined and traces of coproporphyrin-III and uroporphyrin-III were identified. This study may therefore help to establish a rapid screening test method with spectroscopic differentiation of the occurring porphyrins, which consequently allows for the distinction of different porphyrias. This may be a valuable tool for clinical porphyria diagnosis and rapid or immediate treatment.

  9. Quantitative fluorescence lifetime spectroscopy in turbid media: comparison of theoretical, experimental and computational methods

    International Nuclear Information System (INIS)

    Vishwanath, Karthik; Mycek, Mary-Ann; Pogue, Brian

    2002-01-01

    A Monte Carlo model developed to simulate time-resolved fluorescence propagation in a semi-infinite turbid medium was validated against previously reported theoretical and computational results. Model simulations were compared to experimental measurements of fluorescence spectra and lifetimes on tissue-simulating phantoms for single and dual fibre-optic probe geometries. Experiments and simulations using a single probe revealed that scattering-induced artefacts appeared in fluorescence emission spectra, while fluorescence lifetimes were unchanged. Although fluorescence lifetime measurements are generally more robust to scattering artefacts than are measurements of fluorescence spectra, in the dual-probe geometry scattering-induced changes in apparent lifetime were predicted both from diffusion theory and via Monte Carlo simulation, as well as measured experimentally. In all cases, the recovered apparent lifetime increased with increasing scattering and increasing source-detector separation. Diffusion theory consistently underestimated the magnitude of these increases in apparent lifetime (predicting a maximum increase of ∼15%), while Monte Carlo simulations and experiment were closely matched (showing increases as large as 30%). These results indicate that quantitative simulations of time-resolved fluorescence propagation in turbid media will be important for accurate recovery of fluorophore lifetimes in biological spectroscopy and imaging applications. (author)

  10. Evaluating Activated Carbon Adsorption of Dissolved Organic Matter and Micropollutants Using Fluorescence Spectroscopy.

    Science.gov (United States)

    Shimabuku, Kyle K; Kennedy, Anthony M; Mulhern, Riley E; Summers, R Scott

    2017-03-07

    Dissolved organic matter (DOM) negatively impacts granular activated carbon (GAC) adsorption of micropollutants and is a disinfection byproduct precursor. DOM from surface waters, wastewater effluent, and 1 kDa size fractions were adsorbed by GAC and characterized using fluorescence spectroscopy, UV-absorption, and size exclusion chromatography (SEC). Fluorescing DOM was preferentially adsorbed relative to UV-absorbing DOM. Humic-like fluorescence (peaks A and C) was selectively adsorbed relative to polyphenol-like fluorescence (peaks T and B) potentially due to size exclusion effects. In the surface waters and size fractions, peak C was preferentially removed relative to peak A, whereas the reverse was found in wastewater effluent, indicating that humic-like fluorescence is associated with different compounds depending on DOM source. Based on specific UV-absorption (SUVA), aromatic DOM was preferentially adsorbed. The fluorescence index (FI), if interpreted as an indicator of aromaticity, indicated the opposite but exhibited a strong relationship with average molecular weight, suggesting that FI might be a better indicator of DOM size than aromaticity. The influence of DOM intermolecular interactions on adsorption were minimal based on SEC analysis. Fluorescence parameters captured the impact of DOM size on the fouling of 2-methylisoborneol and warfarin adsorption and correlated with direct competition and pore blockage indicators.

  11. In-vivo optical detection of cancer using chlorin e6 – polyvinylpyrrolidone induced fluorescence imaging and spectroscopy

    International Nuclear Information System (INIS)

    Chin, William WL; Thong, Patricia SP; Bhuvaneswari, Ramaswamy; Soo, Khee Chee; Heng, Paul WS; Olivo, Malini

    2009-01-01

    Photosensitizer based fluorescence imaging and spectroscopy is fast becoming a promising approach for cancer detection. The purpose of this study was to examine the use of the photosensitizer chlorin e6 (Ce6) formulated in polyvinylpyrrolidone (PVP) as a potential exogenous fluorophore for fluorescence imaging and spectroscopic detection of human cancer tissue xenografted in preclinical models as well as in a patient. Fluorescence imaging was performed on MGH human bladder tumor xenografted on both the chick chorioallantoic membrane (CAM) and the murine model using a fluorescence endoscopy imaging system. In addition, fiber optic based fluorescence spectroscopy was performed on tumors and various normal organs in the same mice to validate the macroscopic images. In one patient, fluorescence imaging was performed on angiosarcoma lesions and normal skin in conjunction with fluorescence spectroscopy to validate Ce6-PVP induced fluorescence visual assessment of the lesions. Margins of tumor xenografts in the CAM model were clearly outlined under fluorescence imaging. Ce6-PVP-induced fluorescence imaging yielded a specificity of 83% on the CAM model. In mice, fluorescence intensity of Ce6-PVP was higher in bladder tumor compared to adjacent muscle and normal bladder. Clinical results confirmed that fluorescence imaging clearly captured the fluorescence of Ce6-PVP in angiosarcoma lesions and good correlation was found between fluorescence imaging and spectral measurement in the patient. Combination of Ce6-PVP induced fluorescence imaging and spectroscopy could allow for optical detection and discrimination between cancer and the surrounding normal tissues. Ce6-PVP seems to be a promising fluorophore for fluorescence diagnosis of cancer

  12. Fluorescence lifetime spectroscopy in multiple-scattering environments: an application to biotechnology

    Science.gov (United States)

    Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio

    1999-07-01

    Over the past few years, there has been significant research activity devoted to the application of fluorescence spectroscopy to strongly scattering media, where photons propagate diffusely. Much of this activity focused on fluorescence as a source of contrast enhancement in optical tomography. Our efforts have emphasized the quantitative recovery of fluorescence parameters for spectroscopy. Using a frequency-domain diffusion-based model, we have successfully recovered the lifetime, the absolute quantum yield, the fluorophore concentration, and the emission spectrum of the fluorophore, as well as the absorption and the reduced scattering coefficients at the emission wavelength of the medium in different measurements. In this contribution, we present a sensitive monitor of the binding between ethidium bromide and bovine cells in fresh milk. The spectroscopic contrast was the approximately tenfold increase in the ethidium bromide lifetime upon binding to DNA. The measurement clearly demonstrated that we could quantitatively measure the density of cells in the milk, which is an application vital to the tremendous economic burden of bovine subclinical mastitis detection. Furthermore, we may in principle use the spirit of this technique as a quantitative monitor of the binding of fluorescent drugs inside tissues. This is a first step towards lifetime spectroscopy in tissues.

  13. Comparison of fluorescence rejection methods of baseline correction and shifted excitation Raman difference spectroscopy

    Science.gov (United States)

    Cai, Zhijian; Zou, Wenlong; Wu, Jianhong

    2017-10-01

    Raman spectroscopy has been extensively used in biochemical tests, explosive detection, food additive and environmental pollutants. However, fluorescence disturbance brings a big trouble to the applications of portable Raman spectrometer. Currently, baseline correction and shifted-excitation Raman difference spectroscopy (SERDS) methods are the most prevailing fluorescence suppressing methods. In this paper, we compared the performances of baseline correction and SERDS methods, experimentally and simulatively. Through the comparison, it demonstrates that the baseline correction can get acceptable fluorescence-removed Raman spectrum if the original Raman signal has good signal-to-noise ratio, but it cannot recover the small Raman signals out of large noise background. By using SERDS method, the Raman signals, even very weak compared to fluorescence intensity and noise level, can be clearly extracted, and the fluorescence background can be completely rejected. The Raman spectrum recovered by SERDS has good signal to noise ratio. It's proved that baseline correction is more suitable for large bench-top Raman system with better quality or signal-to-noise ratio, while the SERDS method is more suitable for noisy devices, especially the portable Raman spectrometers.

  14. Optical fluorescence spectroscopy to detect hepatic necrosis after normothermic ischemia: animal model

    Science.gov (United States)

    Romano, Renan A.; Vollet-Filho, Jose D.; Pratavieira, Sebastião.; Fernandez, Jorge L.; Kurachi, Cristina; Bagnato, Vanderlei S.; Castro-e-Silva, Orlando; Sankarankutty, Ajith K.

    2015-06-01

    Liver transplantation is a well-established treatment for liver failure. However, the success of the transplantation procedure depends on liver graft conditions. The tissue function evaluation during the several transplantation stages is relevant, in particular during the organ harvesting, when a decision is made concerning the viability of the graft. Optical fluorescence spectroscopy is a good option because it is a noninvasive and fast technique. A partial normothermic hepatic ischemia was performed in rat livers, with a vascular occlusion of both median and left lateral lobes, allowing circulation only for the right lateral lobe and the caudate lobe. Fluorescence spectra under excitation at 532 nm (doubled frequency Nd:YAG laser) were collected using a portable spectrometer (USB2000, Ocean Optics, USA). The fluorescence emission was collected before vascular occlusion, after ischemia, and 24 hours after reperfusion. A morphometric histology analysis was performed as the gold standard evaluation - liver samples were analyzed, and the percentage of necrotic tissue was obtained. The results showed that changes in the fluorescence emission after ischemia can be correlated with the amount of necrosis evaluated by a morphometric analysis, the Pearson correlation coefficient of the generated model was 0.90 and the root mean square error was around 20%. In this context, the laser-induced fluorescence spectroscopy technique after normothermic ischemia showed to be a fast and efficient method to differentiate ischemic injury from viable tissues.

  15. Fluorescence suppression using wavelength modulated Raman spectroscopy in fiber-probe-based tissue analysis.

    Science.gov (United States)

    Praveen, Bavishna B; Ashok, Praveen C; Mazilu, Michael; Riches, Andrew; Herrington, Simon; Dholakia, Kishan

    2012-07-01

    In the field of biomedical optics, Raman spectroscopy is a powerful tool for probing the chemical composition of biological samples. In particular, fiber Raman probes play a crucial role for in vivo and ex vivo tissue analysis. However, the high-fluorescence background typically contributed by the auto fluorescence from both a tissue sample and the fiber-probe interferes strongly with the relatively weak Raman signal. Here we demonstrate the implementation of wavelength-modulated Raman spectroscopy (WMRS) to suppress the fluorescence background while analyzing tissues using fiber Raman probes. We have observed a significant signal-to-noise ratio enhancement in the Raman bands of bone tissue, which have a relatively high fluorescence background. Implementation of WMRS in fiber-probe-based bone tissue study yielded usable Raman spectra in a relatively short acquisition time (∼30  s), notably without any special sample preparation stage. Finally, we have validated its capability to suppress fluorescence on other tissue samples such as adipose tissue derived from four different species.

  16. Reduced density-matrix functional theory: Correlation and spectroscopy.

    Science.gov (United States)

    Di Sabatino, S; Berger, J A; Reining, L; Romaniello, P

    2015-07-14

    In this work, we explore the performance of approximations to electron correlation in reduced density-matrix functional theory (RDMFT) and of approximations to the observables calculated within this theory. Our analysis focuses on the calculation of total energies, occupation numbers, removal/addition energies, and spectral functions. We use the exactly solvable Hubbard dimer at 1/4 and 1/2 fillings as test systems. This allows us to analyze the underlying physics and to elucidate the origin of the observed trends. For comparison, we also report the results of the GW approximation, where the self-energy functional is approximated, but no further hypothesis is made concerning the approximations of the observables. In particular, we focus on the atomic limit, where the two sites of the dimer are pulled apart and electrons localize on either site with equal probability, unless a small perturbation is present: this is the regime of strong electron correlation. In this limit, using the Hubbard dimer at 1/2 filling with or without a spin-symmetry-broken ground state allows us to explore how degeneracies and spin-symmetry breaking are treated in RDMFT. We find that, within the used approximations, neither in RDMFT nor in GW, the signature of strong correlation is present, when looking at the removal/addition energies and spectral function from the spin-singlet ground state, whereas both give the exact result for the spin-symmetry broken case. Moreover, we show how the spectroscopic properties change from one spin structure to the other.

  17. Epoxy matrix with triaromatic mesogenic unit in dielectric spectroscopy observation

    Science.gov (United States)

    Włodarska, Magdalena; Mossety-Leszczak, Beata; Bąk, Grzegorz W.; Kisiel, Maciej; Dłużniewski, Maciej; Okrasa, Lidia

    2018-04-01

    This paper describes the dielectric response of a selected liquid crystal epoxy monomer (plain and in curing systems) in a wide range of frequency and temperature. The dielectric spectroscopy, thanks to its sensitivity, is a very good tool for studying phase transitions, reaction progress, or material properties. This sensitivity is important in the case of liquid crystal epoxy resins, where properties of the final network depend on the choice of monomers, curing agents, curing conditions and post-curing treatment, or applying an external electric or magnetic field during the reaction. In most of the obtained cured products, the collected dielectric data show two relaxation processes. The α-process is related to a structural reorientation; it can usually be linked with the glass transition and the mechanical properties of the material. The β-process can be identified as a molecular motion process, probably associated with the carboxyl groups in the mesogen. A transient Maxwell-Wagner relaxation observed in one of the compositions after the initial curing is removed by post-curing treatment at elevated temperatures. Post-curing is therefore necessary for obtaining uniformly cured products in those cases. In the investigated systems, the choice of a curing agent can change the glass transition temperature by at least 70 °C. The obtained results are in a good agreement with an earlier study employing other techniques. Finally, we assess the influence of the direction of mesogen alignment on the dielectric properties of one selected system, where a global order was induced by applying an external magnetic field in the course of curing.

  18. Two-photon-excited fluorescence spectroscopy of atomic fluorine at 170 nm

    Science.gov (United States)

    Herring, G. C.; Dyer, Mark J.; Jusinski, Leonard E.; Bischel, William K.

    1988-01-01

    Two-photon-excited fluorescence spectroscopy of atomic fluorine is reported. A doubled dye laser at 286-nm is Raman shifted in H2 to 170 nm (sixth anti-Stokes order) to excite ground-state 2P(0)J fluorine atoms to the 2D(0)J level. The fluorine atoms are detected by one of two methods: observing the fluorescence decay to the 2PJ level or observing F(+) production through the absorption of an additional photon by the excited atoms. Relative two-photon absorption cross sections to and the radiative lifetimes of the 2D(0)J states are measured.

  19. Diode-Laser Induced Fluorescence Spectroscopy of an Optically Thick Plasma in Combination with Laser Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    S. Nomura

    2013-01-01

    Full Text Available Distortion of laser-induced fluorescence profiles attributable to optical absorption and saturation broadening was corrected in combination with laser absorption spectroscopy in argon plasma flow. At high probe-laser intensity, saturated absorption profiles were measured to correct probe-laser absorption. At low laser intensity, nonsaturated absorption profiles were measured to correct fluorescence reabsorption. Saturation broadening at the measurement point was corrected using a ratio of saturated to non-saturated broadening. Observed LIF broadening and corresponding translational temperature without correction were, respectively, 2.20±0.05 GHz and 2510±100 K and corrected broadening and temperature were, respectively, 1.96±0.07 GHz and 1990±150 K. Although this correction is applicable only at the center of symmetry, the deduced temperature agreed well with that obtained by LAS with Abel inversion.

  20. Application of EEM fluorescence spectroscopy in understanding of the "LIGA" phenomenon in the Bay of Biscay (France)

    Science.gov (United States)

    Parot, Jérémie; Susperregui, Nicolas; Rouaud, Vanessa; Dubois, Laurent; Anglade, Nathalie; Parlanti, Edith

    2014-05-01

    Marine mucilage is present in all oceans over the world, and in particular in the Mediterranean Sea and in the Pacific Ocean. Surface water warming and hydrodynamic processes can favor the coalescence of marine mucilage, large marine aggregates representing an ephemeral and extreme habitat for biota. DOM is a heterogeneous, complex mixture of compounds, including extracellular polymeric substances (EPS), with wide ranging chemical properties and it is well known to interact with pollutants and to affect their transport and their fate in aquatic environment. The LIGA French research program focuses on tracing colloidal dissolved organic matter (DOM) sources and cycling in the Bay of Biscay (South Western French coast). This ephemeral phenomenon (called "LIGA" in the South West of France) has been observed more than 750 times since 2010. It presents a great ecological impact on marine ecosystems and has been shown to be concomitant with the development of pathogen organisms. A one-year intensive survey of fluorescent DOM was undertaken. From April 2013 until May 2014, water samples were monthly collected from the Adour River (main fresh water inputs) and from 2 sites in the Bay of Biscay at 3 depths of the water column (surface water, at the maximum of chlorophyll-a, and deep water). Moreover, intensified samplings took place from the appearance of the phenomenon twice a week during 4 weeks. UV/visible absorbance and excitation emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses have been used to characterize colloidal DOM in the Bay of Biscay in order to estimate DOM sources as well as spatial and temporal variability of DOM properties. The preliminary results, obtained for about 70 samples of this survey, have already highlighted spatial and temporal variations of DOM optical properties and a peculiar fluorescent component (exc300nm/em338nm) was detected while the LIGA phenomenon arises. The appearance of this specific

  1. Synergy Effect of Combining Fluorescence and Mid Infrared Fiber Spectroscopy for Kidney Tumor Diagnostics

    Directory of Open Access Journals (Sweden)

    Andrey Bogomolov

    2017-11-01

    Full Text Available Matching pairs of tumor and non-tumor kidney tissue samples of four patients were investigated ex vivo using a combination of two methods, attenuated total reflection mid infrared spectroscopy and fluorescence spectroscopy, through respectively prepared and adjusted fiber probes. In order to increase the data information content, the measurements on tissue samples in both methods were performed in the same 31 preselected positions. Multivariate data analysis revealed a synergic effect of combining the two methods for the diagnostics of kidney tumor compared to individual techniques.

  2. Differential laser-induced perturbation spectroscopy and fluorescence imaging for biological and materials sensing

    Science.gov (United States)

    Burton, Dallas Jonathan

    The field of laser-based diagnostics has been a topic of research in various fields, more specifically for applications in environmental studies, military defense technologies, and medicine, among many others. In this dissertation, a novel laser-based optical diagnostic method, differential laser-induced perturbation spectroscopy (DLIPS), has been implemented in a spectroscopy mode and expanded into an imaging mode in combination with fluorescence techniques. The DLIPS method takes advantage of deep ultraviolet (UV) laser perturbation at sub-ablative energy fluences to photochemically cleave bonds and alter fluorescence signal response before and after perturbation. The resulting difference spectrum or differential image adds more information about the target specimen, and can be used in combination with traditional fluorescence techniques for detection of certain materials, characterization of many materials and biological specimen, and diagnosis of various human skin conditions. The differential aspect allows for mitigation of patient or sample variation, and has the potential to develop into a powerful, noninvasive optical sensing tool. The studies in this dissertation encompass efforts to continue the fundamental research on DLIPS including expansion of the method to an imaging mode. Five primary studies have been carried out and presented. These include the use of DLIPS in a spectroscopy mode for analysis of nitrogen-based explosives on various substrates, classification of Caribbean fruit flies versus Caribbean fruit flies that have been irradiated with gamma rays, and diagnosis of human skin cancer lesions. The nitrogen-based explosives and Caribbean fruit flies have been analyzed with the DLIPS scheme using the imaging modality, providing complementary information to the spectroscopic scheme. In each study, a comparison between absolute fluorescence signals and DLIPS responses showed that DLIPS statistically outperformed traditional fluorescence techniques

  3. Determination of Dynamics of Plant Plasma Membrane Proteins with Fluorescence Recovery and Raster Image Correlation Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Laňková, Martina; Humpolíčková, Jana; Vosolsobě, S.; Cit, Zdeněk; Lacek, Jozef; Čovan, Martin; Čovanová, Milada; Hof, Martin; Petrášek, Jan

    2016-01-01

    Roč. 22, č. 2 (2016), s. 290-299 ISSN 1431-9276 R&D Projects: GA ČR(CZ) GAP305/11/2476; GA ČR(CZ) GPP501/12/P951 Institutional support: RVO:61389030 ; RVO:61388955 Keywords : raster image correlation spectroscopy * fluorescence recovery after photobleaching * auxin influx Subject RIV: EB - Genetics ; Molecular Biology; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 1.891, year: 2016

  4. Recent Developments in Fluorescence Correlation Spectroscopy for Diffusion Measurements in Planar Lipid Membranes

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Hof, Martin

    2010-01-01

    Roč. 11, č. 2 (2010), s. 427-457 E-ISSN 1422-0067 R&D Projects: GA ČR GA203/08/0114; GA AV ČR GEMEM/09/E006 Institutional research plan: CEZ:AV0Z40400503 Keywords : lateral diffusion * fluorescence fluctuation spectroscopy * confocal microscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.279, year: 2010

  5. Assessment of drinking water quality at the tap using fluorescence spectroscopy

    OpenAIRE

    Heibati, Masoumeh; Stedmon, Colin A; Stenroth, Karolina; Rauch, Sebastien; Toljander, Jonas; Säve-Söderbergh, Melle; Murphy, Kathleen R.

    2017-01-01

    Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the syst...

  6. Fluorescence lifetime correlation spectroscopy combined with lifetime tuning: New perspectives in supported phospholipid bilayer research

    Czech Academy of Sciences Publication Activity Database

    Benda, Aleš; Fagulová, Veronika; Deyneka, Alexander; Enderlain, J.; Hof, Martin

    2006-01-01

    Roč. 22, č. 23 (2006), s. 9580-9585 ISSN 0743-7463 R&D Projects: GA ČR GA203/05/2308; GA MŠk LC06063 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100522 Keywords : spectroscopy * fluorescence * FLCS Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.902, year: 2006

  7. Transition probability of the 5971-A line in neutral uranium from collision-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gagne, J.M.; Mongeau, B.; Demers, Y.; Pianarosa, P.

    1981-01-01

    From collision-induced fluorescence spectroscopy measurements, we have determined the transition probability Aof the 5971-A transition in neutral uranium. Our value, A 5971 = (5.9 +- 1.8) x 10 5 sec -1 , is, within experimental error, in good agreement with the previous determination of Corliss, A 5971 = (7.3 +- 3.0) x 10 5 sec -1 [J. Res. Nat. Bur. Stand. Sect. A 80,1 (1976)

  8. Fluorescence spectroscopy for assessment of liver transplantation grafts concerning graft viability and patient survival

    Science.gov (United States)

    Vollet Filho, José D.; da Silveira, Marina R.; Castro-e-Silva, Orlando; Bagnato, Vanderlei S.; Kurachi, Cristina

    2015-06-01

    Evaluating transplantation grafts at harvest is essential for its success. Laser-induced fluorescence spectroscopy (LIFS) can help monitoring changes in metabolic/structural conditions of tissue during transplantation. The aim of the present study is to correlate LIFSobtained spectra of human hepatic grafts during liver transplantation with post-operative patients' mortality rate and biochemical parameters, establishing a method to exclude nonviable grafts before implantation. Orthotopic liver transplantation, piggyback technique was performed in 15 patients. LIFS was performed under 408nm excitation. Collection was performed immediately after opening donor's abdominal cavity, after cold perfusion, end of back-table period, and 5 min and 1 h after warm perfusion at recipient. Fluorescence information was compared to lactate, creatinine, bilirubin and INR levels and to survival status. LIFS was sensitive to liver changes during transplantation stages. Study-in-progress; initial results indicate correlation between fluorescence and life/death status of patients.

  9. Sizes of water-soluble luminescent quantum dots measured by fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Zhang Pudun; Li Liang; Dong Chaoqing; Qian Huifeng; Ren Jicun

    2005-01-01

    In this paper, fluorescence correlation spectroscopy (FCS) was applied to measure the size of water-soluble quantum dots (QDs). The measurements were performed on a home-built FCS system based on the Stokes-Einstein equation. The obtained results showed that for bare CdTe QDs the sizes from FCS were larger than the ones from transmission electron microscopy (TEM). The brightness of QDs was also evaluated using FCS technique. It was found that the stability of the surface chemistry of QDs would be significantly improved by capping it with hard-core shell. Our data demonstrated that FCS is a simple, fast, and effective method for characterizing the fluorescent quantum dots, and is especially suitable for determining the fluorescent nanoparticles less than 10 nm in water solution

  10. Quantitative generalized ratiometric fluorescence spectroscopy for turbid media based on probe encapsulated by biologically localized embedding

    International Nuclear Information System (INIS)

    Yan, Xiu-Fang; Chen, Zeng-Ping; Cui, Yin-Yin; Hu, Yuan-Liang; Yu, Ru-Qin

    2016-01-01

    PEBBLE (probe encapsulated by biologically localized embedding) nanosensor encapsulating an intensity-based fluorescence indicator and an inert reference fluorescence dye inside the pores of stable matrix can be used as a generalized wavelength-ratiometric probe. However, the lack of an efficient quantitative model render the choices of inert reference dyes and intensity-based fluorescence indicators used in PEBBLEs based generalized wavelength-ratiometric probes rather limited. In this contribution, an extended quantitative fluorescence model was derived specifically for generalized wavelength-ratiometric probes based on PEBBLE technique (QFM GRP ) with a view to simplify the design of PEBBLEs and hence further extend their application potentials. The effectiveness of QFM GRP has been tested on the quantitative determination of free Ca 2+ in both simulated and real turbid media using a Ca 2+ sensitive PEBBLE nanosensor encapsulating Rhod-2 and eosin B inside the micropores of stable polyacrylamide matrix. Experimental results demonstrated that QFM GRP could realize precise and accurate quantification of free Ca 2+ in turbid samples, even though there is serious overlapping between the fluorescence excitation peaks of eosin B and Ca 2+ bound Rhod-2. The average relative predictive error value of QFM GRP for the test simulated turbid samples was 5.9%, about 2–4 times lower than the corresponding values of partial least squares calibration model and the empirical ratiometric model based on the ratio of fluorescence intensities at the excitation peaks of Ca 2+ bound Rhod-2 and eosin B. The recovery rates of QFM GRP for the real and spiked turbid samples varied from 93.1% to 101%, comparable to the corresponding results of atomic absorption spectrometry. - Highlights: • An advanced model was derived for generalized wavelength-ratiometric PEBBLEs. • The model can simplify the design of generalized wavelength-ratiometric PEBBLEs. • The model realized accurate

  11. Blood perfusion and pH monitoring in organs by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Vari, Sandor G.; Papazoglou, Theodore G.; Pergadia, Vani R.; Stavridi, Marigo; Snyder, Wendy J.; Papaioannou, Thanassis; Duffy, J. T.; Weiss, Andrew B.; Thomas, Reem; Grundfest, Warren S.

    1994-01-01

    Sensitivity of laser-induced fluorescence spectroscopy (LIFS) in detecting a change in tissue pH, and blood perfusion was determined. Rabbits were anesthetized, paralyzed, and mechanically ventilated. The arterial and venous blood supplies of the kidney were isolated and ligated to alter the perfusion. The femoral artery was cannulated to extract samples for blood gas analysis. A 308-nm XeCl was used as an excitation source. A 600 micrometers core diameter fiber was used for fluorescence acquisition, and the spectra analyzed by an optical multichannel analyzer (EG & G, OMA III). the corresponding intensity ratio R equals INADH / ICOLL was used as an index for respiratory acidosis. Blood perfusion was assessed using the following algorithm: (IELAS minus ICOLL) divided by (INADH minus ICOLL). The intensity ratio linearly decreased with the reduction of blood perfusion. When we totally occluded the artery the ratio decreased tenfold when compared to the ratio of a fully perfused kidney. Results of monitoring blood acidosis by laser-induced fluorescence spectroscopy shows a significant trend between pH and intensity ratio. Since all the slopes were negative, there is an obvious significant correlation between the pH and NADH.COLLAGEN RATIO. Blue-light-induced fluorescence measurements and ratio fluorometry is a sensitive method for monitoring blood perfusion and acidity or alkalinity of an organ.

  12. Quantitative structural modeling on the wavelength interval (Δλ) in synchronous fluorescence spectroscopy

    Science.gov (United States)

    Samari, Fayezeh; Yousefinejad, Saeed

    2017-11-01

    Emission fluorescence spectroscopy has an extremely restricted scope of application to analyze of complex mixtures since its selectivity is reduced by the extensive spectral overlap. Synchronous fluorescence spectroscopy (SFS) is a technique enables us to analyze complex mixtures with overlapped emission and/or excitation spectra. The difference of excitation and emission wavelength of compounds (interval wavelength or Δλ) is an important characteristic in SFS. Thus a multi-parameter model was constructed to predict Δλ in 63 fluorescent compounds and the regression coefficient in training set, cross validation and test set were 0.88, 0.85 and 0.91 respectively. Furthermore, the applicability and validity of model were evaluated using different statistical methods such as y-scrambling and applicability domain. It was concluded that increasing average valence connectivity, number of Al2-NH functional group and Geary autocorrelation (lag 4) with electronegative weights can lead to increasing Δλ in the fluorescent compounds. The current study obtained an insight into the structural properties of compounds effective on their Δλ as an important parameter in SFS.

  13. Dual-wavelength external cavity laser device for fluorescence suppression in Raman spectroscopy

    Science.gov (United States)

    Zhang, Xuting; Cai, Zhijian; Wu, Jianhong

    2017-10-01

    Raman spectroscopy has been widely used in the detection of drugs, pesticides, explosives, food additives and environmental pollutants, for its characteristics of fast measurement, easy sample preparation, and molecular structure analyzing capability. However, fluorescence disturbance brings a big trouble to these applications, with strong fluorescence background covering up the weak Raman signals. Recently shifted excitation Raman difference spectroscopy (SERDS) not only can completely remove the fluorescence background, but also can be easily integrated into portable Raman spectrometers. Usually, SERDS uses two lasers with small wavelength gap to excite the sample, then acquires two spectra, and subtracts one to the other to get the difference spectrum, where the fluorescence background will be rejected. So, one key aspects of successfully applying SERDS method is to obtain a dual-wavelength laser source. In this paper, a dual-wavelength laser device design based on the principles of external cavity diode laser (ECDL) is proposed, which is low-cost and compact. In addition, it has good mechanical stability because of no moving parts. These features make it an ideal laser source for SERDS technique. The experiment results showed that the device can emit narrow-spectral-width lasers of two wavelengths, with the gap smaller than 2 nanometers. The laser power corresponding to each wavelength can be up to 100mW.

  14. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  15. Measurement of the spectrum of electric-field fluctuations in a plasma by laser-fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Hildebrandt, J.; Kunze, H.

    1980-01-01

    Laser-fluorescence spectroscopy has been applied to measure the spectrum of electric wave fields with high temporal resolution in a pulsed hollow-cathode discharge. A low-frequency and a high-frequency component can be identified

  16. DETECTION OF MERCURIC BROMIDE IN A GAS PHASE FLOW CELL BY LASER PHOTOFRAGMENT FLUORESCENCE SPECTROSCOPY. (R825380)

    Science.gov (United States)

    Photofragment fluorescence (PFF) spectroscopy offers real-time monitoring capability with high-analytical sensitivity and selectivity for volatile mercury compounds found in process gas streams, such as incinerator stacks. In this work, low concentrations (6 ppb to...

  17. Assessment of drinking water quality at the tap using fluorescence spectroscopy.

    Science.gov (United States)

    Heibati, Masoumeh; Stedmon, Colin A; Stenroth, Karolina; Rauch, Sebastien; Toljander, Jonas; Säve-Söderbergh, Melle; Murphy, Kathleen R

    2017-11-15

    Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the system, but how much natural variation to expect in a stable distribution system is unknown. In this study, relationships between DOM optical properties, microbial indicator organisms and trace elements were investigated for households connected to a biologically-stable drinking water distribution system. Across the network, humic-like fluorescence intensities showed limited variation (RSD = 3.5-4.4%), with half of measured variation explained by interactions with copper. After accounting for quenching by copper, fluorescence provided a very stable background signal (RSD infiltration of soil water would be detectable. Smaller infiltrations would be detectable in the case of contamination by sewage with a strong tryptophan-like fluorescence signal. These findings indicate that DOM fluorescence is a sensitive indicator of water quality changes in drinking water networks, as long as potential interferents are taken into account. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. On the performance of bioanalytical fluorescence correlation spectroscopy measurements in a multiparameter photon-counting microscope

    Energy Technology Data Exchange (ETDEWEB)

    Mazouchi, Amir; Liu Baoxu; Bahram, Abdullah [Department of Physics, Institute for Optical Sciences, University of Toronto, Toronto (Canada); Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6 (Canada); Gradinaru, Claudiu C., E-mail: claudiu.gradinaru@utoronto.ca [Department of Physics, Institute for Optical Sciences, University of Toronto, Toronto (Canada); Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6 (Canada)

    2011-02-28

    Fluorescence correlation spectroscopy (FCS) data acquisition and analysis routines were developed and implemented in a home-built, multiparameter photon-counting microscope. Laser excitation conditions were investigated for two representative fluorescent probes, Rhodamine110 and enhanced green fluorescent protein (EGFP). Reliable local concentrations and diffusion constants were obtained by fitting measured FCS curves, provided that the excitation intensity did not exceed 20% of the saturation level for each fluorophore. Accurate results were obtained from FCS measurements for sample concentrations varying from pM to {mu}M range, as well as for conditions of high background signals. These experimental constraints were found to be determined by characteristics of the detection system and by the saturation behavior of the fluorescent probes. These factors actually limit the average number of photons that can be collected from a single fluorophore passing through the detection volume. The versatility of our setup and the data analysis capabilities were tested by measuring the mobility of EGFP in the nucleus of Drosophila cells under conditions of high concentration and molecular crowding. As a bioanalytical application, we studied by FCS the binding affinity of a novel peptide-based drug to the cancer-regulating STAT3 protein and corroborated the results with fluorescence polarization analysis derived from the same photon data.

  19. Characterization of the photoreaction between DNA and aminomethyl-trimethylpsoralen using absorption and fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Johnston, B.H.; Hearst, J.E.

    1981-01-01

    The use of absorption and fluorescence spectroscopy for following the progress of the photoreaction between DNA and 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT) has been investigated. Absorption at long wavelengths and fluorescence both decline upon intercalation of AMT into the DNA helix. The loss of fluorescence from AMT and the accompanying appearance of monoadduct fluorescence upon irradiation by UV light can be easily followed by using the excitation beam of a spectrofluorometer as the source of irradiation and monitoring the changing emission spectrum. Where cross-link formation is possible, the subsequent decline of monoadduct fluorescence is seen as well. This suggests that the 4',5'-monoadduct is a precursor of cross-links. Both monoaddition and cross-linking are more rapid with poly d(A-T) than with calf thymus DNA or poly d(A.T). Excitation spectra can be helpful in resolving the levels of AMT and 4',5'-monoadduct when both are contributing to the emission spectrum. Some changes are observed in the emission spectrum of AMT-poly d(A.T) monoadducts after prolonged irradiation which indicate further photoreaction. (author)

  20. Solution conformation of 2-aminopurine dinucleotide determined by ultraviolet two-dimensional fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Widom, Julia R; Marcus, Andrew H; Johnson, Neil P; Von Hippel, Peter H

    2013-01-01

    We have observed the conformation-dependent electronic coupling between the monomeric subunits of a dinucleotide of 2-aminopurine (2-AP), a fluorescent analogue of the nucleic acid base adenine. This was accomplished by extending two-dimensional fluorescence spectroscopy (2D FS)—a fluorescence-detected variation of 2D electronic spectroscopy—to excite molecular transitions in the ultraviolet (UV) regime. A collinear sequence of four ultrafast laser pulses centered at 323 nm was used to resonantly excite the coupled transitions of 2-AP dinucleotide. The phases of the optical pulses were continuously swept at kilohertz frequencies, and the ensuing nonlinear fluorescence was phase-synchronously detected at 370 nm. Upon optimization of a point–dipole coupling model to our data, we found that in aqueous buffer the 2-AP dinucleotide adopts an average conformation in which the purine bases are non-helically stacked (center-to-center distance R 12 = 3.5 ± 0.5 Å , twist angle θ 12 = 5° ± 5° ), which differs from the conformation of such adjacent bases in duplex DNA. These experiments establish UV–2D FS as a method for examining the local conformations of an adjacent pair of fluorescent nucleotides substituted into specific DNA or RNA constructs, which will serve as a powerful probe to interpret, in structural terms, biologically significant local conformational changes within the nucleic acid framework of protein–nucleic acid complexes. (paper)

  1. Monitoring of petroleum hydrocarbon pollution in surface waters by a direct comparison of fluorescence spectroscopy and remote sensing techniques

    Energy Technology Data Exchange (ETDEWEB)

    De Domenico, L.; Crisafi, E. (Consiglio Nazionale delle Ricerche, Messina (Italy). Thalassografic Inst.); Magazzu, G. (Lecce Univ. (Italy). Dept. of Biology); Puglisi, A. (Mediterranean Oceanological Centre (CEOM), Palermo (Italy)); La Rosa, A. (Air-Survey, Italy s.r.l., Catania (Italy))

    1994-10-01

    Oil pollution levels were estimated using simultaneous acquisition of data from remote sensing by helicopter and fluorescence spectroscopy on surface samples. Laboratory quantitative analysis of hydrocarbons was used to calibrate remotely sensed data. The data were treated using a computer to generate a colour-coded map not attainable with conventional methods representing seawater pollution. Results were in good agreement and indicated that remotely sensed data together with those achieved by fluorescence spectroscopy are applicable for monitoring hydrocarbon pollution. (author)

  2. Monitoring of petroleum hydrocarbon pollution in surface waters by a direct comparison of fluorescence spectroscopy and remote sensing techniques

    International Nuclear Information System (INIS)

    De Domenico, L.; Crisafi, E.; La Rosa, A.

    1994-01-01

    Oil pollution levels were estimated using simultaneous acquisition of data from remote sensing by helicopter and fluorescence spectroscopy on surface samples. Laboratory quantitative analysis of hydrocarbons was used to calibrate remotely sensed data. The data were treated using a computer to generate a colour-coded map not attainable with conventional methods representing seawater pollution. Results were in good agreement and indicated that remotely sensed data together with those achieved by fluorescence spectroscopy are applicable for monitoring hydrocarbon pollution. (author)

  3. Online fluorescence spectroscopy for the real-time evaluation of the microbial quality of drinking water.

    Science.gov (United States)

    Sorensen, J P R; Vivanco, A; Ascott, M J; Gooddy, D C; Lapworth, D J; Read, D S; Rushworth, C M; Bucknall, J; Herbert, K; Karapanos, I; Gumm, L P; Taylor, R G

    2018-06-15

    We assessed the utility of online fluorescence spectroscopy for the real-time evaluation of the microbial quality of untreated drinking water. Online fluorimeters were installed on the raw water intake at four groundwater-derived UK public water supplies alongside existing turbidity sensors that are used to forewarn of the presence of microbial contamination in the water industry. The fluorimeters targeted fluorescent dissolved organic matter (DOM) peaks at excitation/emission wavelengths of 280/365 nm (tryptophan-like fluorescence, TLF) and 280/450 nm (humic-like fluorescence, HLF). Discrete samples were collected for Escherichia coli, total bacterial cell counts by flow cytometry, and laboratory-based fluorescence and absorbance. Both TLF and HLF were strongly correlated with E. coli (ρ = 0.71-0.77) and total bacterial cell concentrations (ρ = 0.73-0.76), whereas the correlations between turbidity and E. coli (ρ = 0.48) and total bacterial cell counts (ρ = 0.40) were much weaker. No clear TLF peak was observed at the sites and all apparent TLF was considered to be optical bleed-through from the neighbouring HLF peak. Therefore, a HLF fluorimeter alone would be sufficient to evaluate the microbial water quality at these sources. Fluorescent DOM was also influenced by site operations such as pump start-up and the precipitation of cations on the sensor windows. Online fluorescent DOM sensors are a better indicator of the microbial quality of untreated drinking water than turbidity and they have wide-ranging potential applications within the water industry. Copyright © 2018 British Geological Survey, a component institute of NERC - 'BGS © NERC 2018'. Published by Elsevier Ltd.. All rights reserved.

  4. Spectroscopy of lithium atoms sublimated from isolation matrix of solid Ne.

    Science.gov (United States)

    Sacramento, R L; Scudeller, L A; Lambo, R; Crivelli, P; Cesar, C L

    2011-10-07

    We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from a solid neon matrix at cryogenic temperatures. The Li atoms are implanted into the Ne matrix by laser ablation of a solid Li precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms at around 12 K. We find interesting differences in the velocity distribution of the released Li atoms from the model developed for our previous experiment with Cr [R. Lambo, C. C. Rodegheri, D. M. Silveira, and C. L. Cesar, Phys. Rev. A 76, 061401(R) (2007)]. This may be due to the sublimation regime, which is at much lower flux for the Li experiment than for the Cr experiment, as well as to the different collisional cross sections between those species to the Ne gas. We find a drift velocity compatible with Li being thermally sublimated at 11-13 K, while the velocity dispersion around this drift velocity is low, around 5-7 K. With a slow sublimation of the matrix we can determine the penetration depth of the laser ablated Li atoms into the Ne matrix, an important information that is not usually available in most matrix isolation spectroscopy setups. The present results with Li, together with the previous results with Cr suggest this to be a general technique for obtaining cryogenic atoms, for spectroscopic studies, as well as for trap loading. The release of the isolated atoms is also a useful tool to study and confirm details of the matrix isolated atoms which are masked or poorly understood in the solid. © 2011 American Institute of Physics

  5. Evaluation of the removal of antiestrogens and antiandrogens via ozone and granular activated carbon using bioassay and fluorescent spectroscopy.

    Science.gov (United States)

    Ma, Dehua; Chen, Lujun; Wu, Yuchao; Liu, Rui

    2016-06-01

    Antiestrogens and antiandrogens are relatively rarely studied endocrine disrupting chemicals which can be found in un/treated wastewaters. Antiestrogens and antiandrogens in the wastewater treatment effluents could contribute to sexual disruption of organisms. In this study, to assess the removal of non-specific antiestrogens and antiandrogens by advanced treatment processes, ozonation and adsorption to granular activated carbon (GAC), the biological activities and excitation emission matrix fluorescence spectroscopy of wastewater were evaluated. As the applied ozone dose increased to 12 mg/L, the antiestrogenic activity dramatically decreased to 3.2 μg 4-hydroxytamoxifen equivalent (4HEQ)/L, with a removal efficiency of 84.8%, while the antiandrogenic activity was 23.1 μg flutamide equivalent (FEQ)/L, with a removal efficiency of 75.5%. The removal of antiestrogenic/antiandrogenic activity has high correlation with the removal of fulvic acid-like materials and humic acid-like organics, suggesting that they can be used as surrogates for antiestrogenic/antiandrogenic activity during ozonation. The adsorption kinetics of antiestrogenic activity and antiandrogenic activity were well described by pseudo-second-order kinetics models. The estimated equilibrium concentration of antiestrogenic activity is 7.9 μg 4HEQ/L with an effective removal efficiency of 70.5%, while the equilibrium concentration of antiandrogenic activity is 33.7 μg FEQ/L with a removal efficiency of 67.0%. Biological activity evaluation of wastewater effluents is an attractive way to assess the removal of endocrine disrupting chemicals by different treatment processes. Fluorescence spectroscopy can be used as a surrogate measure of bioassays during ozonation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Dual time-resolved temperature-jump fluorescence and infrared spectroscopy for the study of fast protein dynamics.

    Science.gov (United States)

    Davis, Caitlin M; Reddish, Michael J; Dyer, R Brian

    2017-05-05

    Time-resolved temperature-jump (T-jump) coupled with fluorescence and infrared (IR) spectroscopy is a powerful technique for monitoring protein dynamics. Although IR spectroscopy of the polypeptide amide I mode is more technically challenging, it offers complementary information because it directly probes changes in the protein backbone, whereas, fluorescence spectroscopy is sensitive to the environment of specific side chains. With the advent of widely tunable quantum cascade lasers (QCL) it is possible to efficiently probe multiple IR frequencies with high sensitivity and reproducibility. Here we describe a dual time-resolved T-jump fluorescence and IR spectrometer and its application to study protein folding dynamics. A Q-switched Ho:YAG laser provides the T-jump source for both time-resolved IR and fluorescence spectroscopy, which are probed by a QCL and Ti:Sapphire laser, respectively. The Ho:YAG laser simultaneously pumps the time-resolved IR and fluorescence spectrometers. The instrument has high sensitivity, with an IR absorbance detection limit of jump induced difference spectrum from 50ns to 0.5ms. This study demonstrates the power of the dual time-resolved T-jump fluorescence and IR spectroscopy to resolve complex folding mechanisms by complementary IR absorbance and fluorescence measurements of protein dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Fluorescence spectroscopy for the detection of potentially malignant disorders of the oral cavity: analysis of 30 cases

    International Nuclear Information System (INIS)

    Francisco, A L N; Correr, W R; Kurachi, C; Azevedo, L H; Galletta, V K; Pinto, C A L; Kowalski, L P

    2014-01-01

    Oral cancer is a major health problem worldwide and although early diagnosis of potentially malignant and malignant diseases is associated with better treatment results, a large number of cancers are initially misdiagnosed, with unfortunate consequences for long-term survival. Fluorescence spectroscopy is a noninvasive modality of diagnostic approach using induced fluorescence emission in tumors that can improve diagnostic accuracy. The objective of this study was to determine the ability to discriminate between normal oral mucosa and potentially malignant disorders by fluorescence spectroscopy. Fluorescence investigation under 408 and 532 nm excitation wavelengths was performed on 60 subjects, 30 with potentially malignant disorders and 30 volunteers with normal mucosa. Data was analyzed to correlate fluorescence patterns with clinical and histopathological diagnostics. Fluorescence spectroscopy used as a point measurement technique resulted in a great variety of spectral information. In a qualitative analysis of the fluorescence spectral characteristics of each type of injury evaluated, it was possible to discriminate between normal and abnormal oral mucosa. The results show the potential use of fluorescence spectroscopy for an improved discrimination of oral disorders. (paper)

  8. Fluorescence spectroscopy of soil pellets : The use of CP/PARAFAC.

    Science.gov (United States)

    Mounier, Stéphane; Nicolodeli, Gustavo; Redon, Roland; Hacherouf, Kalhed; Milori, Debora M. B. P.

    2014-05-01

    Fluorescence spectroscopy is one of the most sensitive techniques available for analytical purposes. It is relatively easy to implement, phenomenologically straightforward and well investigated. Largely non-invasive and fast, so that it can be useful for environmental applications. Fluorescence phenomenon is highly probable in molecular systems containing atoms with lone pairs of electrons such as C=O, aromatic, phenolic, quinone and more rigid unsaturated conjugated systems. These functional groups are present in humic substances (HS) from soils (Senesi, 1990; N. Senesi et al., 1991) and represent the main fluorophors of Soil Organic Matter (SOM). The extension of the conjugated electronic system, the level of heteroatom substitution and type and number of substituting groups under the aromatic rings strongly affect the intensity and wavelength of molecular fluorescence. However, to analyse the SOM it is generally done a chemical extraction that allows measuring the fluorescence response of the liquid extract. To avoid this fractionation of the SOM, Milori et al. (2006) proposed the application of laser induced fluorescence spectroscopy (LIFS) in whole soil. This work intends to assess the technical feasibility of 3D fluorescence spectroscopy using lamp for excitation to analyse solids opaque samples prepared with different substances. Seventy four (74) solid samples were prepared from different mixtures of boric acid (BA), humic substance acid and tryptophan (TRP) powder. The compounds were mixture and a pellet was done by using pressure (8 ton). The pellets were measured using a spectrofluorimeter HITACHI F4500, and a 3D fluorescence tensor was done from emission spectra (200-600 nm) with excitation range from 200 to 500 nm. The acquisition parameters were: step at 5 nm, scan speed at 2400 nm.min-1, response time at 0.1 s, excitation and emission slits at 5 nm and photomultiplier voltage at 700 V. Furthermore, measures of Laser-induced Fluorescence were

  9. Laser Induced Fluorescence Spectroscopy of Neutral and Ionized Polycyclic Aromatic Hydrocarbons in the Cosmic Simulation Chamber

    Science.gov (United States)

    Bejaoui, Salma; Salama, Farid; Contreras, Cesar; Sciamma O'Brien, Ella; Foing, Bernard; Pascale, Ehrenfreund

    2015-01-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are considered the best carriers to account for the ubiquitous infrared emission bands. PAHs have also been proposed as candidates to explain the diffuse interstellar bands (DIBs), a series of absorption features seen on the interstellar extinction curve and are plausible carriers for the extended red emission (ERE), a photoluminescent process associated with a wide variety of interstellar environments. Extensive efforts have been devoted over the past two decades to characterize the physical and chemical properties of PAH molecules and ions in space. Absorption spectra of PAH molecules and ions trapped in solid matrices have been compared to the DIBs. Absorption spectra of several cold, isolated gas-phase PAHs have also been measured under experimental conditions that mimic the interstellar conditions. The purpose of this study is to provide a new dimension to the existing spectroscopic database of neutral and single ionized PAHs that is largely based on absorption spectra by adding emission spectroscopy data. The measurements are based on the laser induced fluorescence (LIF) technique and are performed with the Pulsed Discharge Nozzle (PDN) of the COSmIC laboratory facility at NASA Ames laboratory. The PDN generates a plasma in a free supersonic jet expansion to simulate the physical and the chemical conditions in interstellar environments. We focus, here, on the fluorescence spectra of large neutral PAHs and their cations where there is a lack of fluorescence spectroscopy data. The astronomical implications of the data (e.g., ERE) are examined.

  10. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy

    Science.gov (United States)

    Rajagopal, Vaishnavi; Stokes, Chris; Ferzoco, Alessandra

    2018-02-01

    We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes.

  11. Fourier transform infrared and fluorescence spectroscopy for analysis of vegetable oils

    Directory of Open Access Journals (Sweden)

    Nigri S.

    2013-09-01

    Full Text Available Fourier transform infrared (FTIR and fluorescence spectroscopy, combined with chemometric approaches have been developed to analysis of extra virgin olive oil adulterated with pomace olive oil. The measurements were made on pure vegetable oils: extra virgin oil, pomace olive oil and that adulterated with varying concentration of pomace olive oil. Today, the application of FTIR spectroscopy has increased in food studied, and particularly has become a powerful analytical tool in the study of edible oils and fats. The spectral regions where the variations were observed chosen for developing models and cross validation was used. The synchronous fluorescence spectrometry takes advantage of the hardware capability to vary both the excitation and emission wavelengths during the analysis with constant wavelength difference is maintained between the two. The region between 300 and 400 nm is attributed to the tocopherols and phenols, the derivatives of vitamin E are associated with the region 400–600 nm and the bands in the region of 600–700 nm are attributed to the chlorophyll and peophytin pigments. The results presented in this study suggest that FTIR and fluorescence may be a useful tool for analysis and detecting adulteration of extra virgin olive oil with pomace oil.

  12. Tissue classification and diagnostics using a fiber probe for combined Raman and fluorescence spectroscopy

    Science.gov (United States)

    Cicchi, Riccardo; Anand, Suresh; Crisci, Alfonso; Giordano, Flavio; Rossari, Susanna; De Giorgi, Vincenzo; Maio, Vincenza; Massi, Daniela; Nesi, Gabriella; Buccoliero, Anna Maria; Guerrini, Renzo; Pimpinelli, Nicola; Pavone, Francesco S.

    2015-07-01

    Two different optical fiber probes for combined Raman and fluorescence spectroscopic measurements were designed, developed and used for tissue diagnostics. Two visible laser diodes were used for fluorescence spectroscopy, whereas a laser diode emitting in the NIR was used for Raman spectroscopy. The two probes were based on fiber bundles with a central multimode optical fiber, used for delivering light to the tissue, and 24 surrounding optical fibers for signal collection. Both fluorescence and Raman spectra were acquired using the same detection unit, based on a cooled CCD camera, connected to a spectrograph. The two probes were successfully employed for diagnostic purposes on various tissues in a good agreement with common routine histology. This study included skin, brain and bladder tissues and in particular the classification of: malignant melanoma against melanocytic lesions and healthy skin; urothelial carcinoma against healthy bladder mucosa; brain tumor against dysplastic brain tissue. The diagnostic capabilities were determined using a cross-validation method with a leave-one-out approach, finding very high sensitivity and specificity for all the examined tissues. The obtained results demonstrated that the multimodal approach is crucial for improving diagnostic capabilities. The system presented here can improve diagnostic capabilities on a broad range of tissues and has the potential of being used for endoscopic inspections in the near future.

  13. Bone matrix calcification during embryonic and postembryonic rat calvarial development assessed by SEM-EDX spectroscopy, XRD, and FTIR spectroscopy.

    Science.gov (United States)

    Henmi, Akiko; Okata, Hiroshi; Anada, Takahisa; Yoshinari, Mariko; Mikami, Yasuto; Suzuki, Osamu; Sasano, Yasuyuki

    2016-01-01

    Bone mineral is constituted of biological hydroxyapatite crystals. In developing bone, the mineral crystal matures and the Ca/P ratio increases. However, how an increase in the Ca/P ratio is involved in maturation of the crystal is not known. The relationships among organic components and mineral changes are also unclear. The study was designed to investigate the process of calcification during rat calvarial bone development. Calcification was evaluated by analyzing the atomic distribution and concentration of Ca, P, and C with scanning electron microscopy (SEM)-energy-dispersive X-ray (EDX) spectroscopy and changes in the crystal structure with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Histological analysis showed that rat calvarial bone formation started around embryonic day 16. The areas of Ca and P expanded, matching the region of the developing bone matrix, whereas the area of C became localized around bone. X-ray diffraction and FTIR analysis showed that the amorphous-like structure of the minerals at embryonic day 16 gradually transformed into poorly crystalline hydroxyapatite, whereas the proportion of mineral to protein increased until postnatal week 6. FTIR analysis also showed that crystallization of hydroxyapatite started around embryonic day 20, by which time SEM-EDX spectroscopy showed that the Ca/P ratio had increased and the C/Ca and C/P ratios had decreased significantly. The study suggests that the Ca/P molar ratio increases and the proportion of organic components such as proteins of the bone matrix decreases during the early stage of calcification, whereas crystal maturation continues throughout embryonic and postembryonic bone development.

  14. Excimer fluorescence of liquid crystalline systems

    Science.gov (United States)

    Sakhno, Tamara V.; Khakhel, Oleg A.; Barashkov, Nikolay N.; Korotkova, Irina V.

    1996-04-01

    The method of synchronous scanning fluorescence spectroscopy shows a presence of dimers of pyrene in a polymeric matrix. The results suggest that excimer formation takes place with dimers in liquid crystalline systems.

  15. Extreme ultraviolet fluorescence spectroscopy of pure and core-shell rare gas clusters at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Schroedter, Lasse

    2013-08-15

    The interaction of rare gas clusters with short-wavelength radiation of free-electron lasers (FELs) has been studied extensively over the last decade by means of electron and ion time-of-flight spectroscopy. This thesis describes the design and construction of a fluorescence spectrometer for the extreme ultraviolet (XUV) spectral range and discusses the cluster experiments performed at FLASH, the Free-electron LAser in Hamburg. Fluorescence of xenon and of argon clusters was studied, both in dependence on the FEL pulse intensity and on the cluster size. The FEL wavelength was set to the giant 4d-resonance of xenon at 13.5 nm and the FEL pulse intensity reached peak values of 2.7.10{sup 15} W/cm{sup 2}. For xenon clusters, charge states of at least 11+ were identified. For argon, charge states up to 7+ were detected. The cluster-size dependent study revealed a decrease of the fluorescence yield per atom with increasing cluster size. This decrease is explained with the help of a geometric model. It assumes that virtually the entire fluorescence yield stems from shells of ions on the cluster surface, whereas ions in the cluster core predominantly recombine non-radiatively with electrons. However, the detailed analysis of fluorescence spectra from clusters consisting of a core of Xe atoms and a surrounding shell of argon atoms shows that, in fact, a small fraction of the fluorescence signal comes from Xe ions in the cluster core. Interestingly, these ions are as highly charged as the ions in the shells of a pure Xe cluster. This result goes beyond the current understanding of charge and energy transfer processes in these systems and points toward the observation of ultrafast charging dynamics in a time window where mass spectrometry is inherently blind. (orig.)

  16. Extreme ultraviolet fluorescence spectroscopy of pure and core-shell rare gas clusters at FLASH

    International Nuclear Information System (INIS)

    Schroedter, Lasse

    2013-08-01

    The interaction of rare gas clusters with short-wavelength radiation of free-electron lasers (FELs) has been studied extensively over the last decade by means of electron and ion time-of-flight spectroscopy. This thesis describes the design and construction of a fluorescence spectrometer for the extreme ultraviolet (XUV) spectral range and discusses the cluster experiments performed at FLASH, the Free-electron LAser in Hamburg. Fluorescence of xenon and of argon clusters was studied, both in dependence on the FEL pulse intensity and on the cluster size. The FEL wavelength was set to the giant 4d-resonance of xenon at 13.5 nm and the FEL pulse intensity reached peak values of 2.7.10 15 W/cm 2 . For xenon clusters, charge states of at least 11+ were identified. For argon, charge states up to 7+ were detected. The cluster-size dependent study revealed a decrease of the fluorescence yield per atom with increasing cluster size. This decrease is explained with the help of a geometric model. It assumes that virtually the entire fluorescence yield stems from shells of ions on the cluster surface, whereas ions in the cluster core predominantly recombine non-radiatively with electrons. However, the detailed analysis of fluorescence spectra from clusters consisting of a core of Xe atoms and a surrounding shell of argon atoms shows that, in fact, a small fraction of the fluorescence signal comes from Xe ions in the cluster core. Interestingly, these ions are as highly charged as the ions in the shells of a pure Xe cluster. This result goes beyond the current understanding of charge and energy transfer processes in these systems and points toward the observation of ultrafast charging dynamics in a time window where mass spectrometry is inherently blind. (orig.)

  17. Investigation of the inclusion behavior between p-sulfoniccalix[8]arene and norfloxacin by fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Wang Xueying; Luo Chuannan; Lv Zhen; Lu Fuguang

    2011-01-01

    The host-guest complexation between p-sulfoniccalix[8]arene (SC 8 A) and norfloxacin (NFLX) in aqueous solution was investigated by fluorescence spectroscopy. Strong fluorescence intensity of the NFLX aqueous solution alone and obvious fluorescence quenching of NFLX solution in the presence of SC 8 A were observed. The fluorescence lifetimes of NFLX and SC 8 A-NFLX inclusion complex were determined and the effect of temperature on SC 8 A-NFLX inclusion complex was studied. The static quenching of the inclusion was obtained, that is the SC 8 A can form a nonfluorescent ground-state inclusion complex with NFLX. As the results show, the combined ratio (n) was 1:1 and association constant K was 1.17x10 5 L/mol. Based on the experimental results, the mechanism of the inclusion complex was explored. The space matching, electrostatic force and hydrogen bond play important effects in the inclusion process. Subsequently, the addition of bovine serum albumin (BSA) solution led to the recovery of fluorescence intensity. It is indicated that BSA can liberate the NFLX into the solution by destructing the SC 8 A-NFLX inclusion complex. Hence SC 8 A may be used for controlled-release drug delivery in the pharmaceutical industry. - Highlights: → Fluorescence lifetimes of NFLX and SC8A-NFLX inclusion complex were determined. → Mechanism of the SC8A-NFLX inclusion complex was explored. → It is proved that SC8A can form a nonfluorescent ground-state inclusion complex with NFLX.

  18. Determination of the botanical origin of honey by front-face synchronous fluorescence spectroscopy.

    Science.gov (United States)

    Lenhardt, Lea; Zeković, Ivana; Dramićanin, Tatjana; Dramićanin, Miroslav D; Bro, Rasmus

    2014-01-01

    Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral (linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240-500 nm for synchronous wavelength intervals of 30-300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.

  19. Effect of tissue scaffold topography on protein structure monitored by fluorescence spectroscopy.

    Science.gov (United States)

    Portugal, Carla A M; Truckenmüller, Roman; Stamatialis, Dimitrios; Crespo, João G

    2014-11-10

    The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell-scaffold interactions. The changes induced upon adsorption of two model proteins with different geometries, trypsin (globular conformation) and fibrinogen (rod-shaped conformation) on poly-l-lactic acid (PLLA) scaffolds with different surface topographies, flat, fibrous and surfaces with aligned nanogrooves, were assessed by fluorescence spectroscopy monitoring, using tryptophan as structural probe. Hence, the maximum emission blue shift and the increase of fluorescence anisotropy observed after adsorption of globular and rod-like shaped proteins on surfaces with parallel nanogrooves were ascribed to more intense protein-surface interactions. Furthermore, the decrease of fluorescence anisotropy observed upon adsorption of proteins to scaffolds with fibrous morphology was more significant for rod-shaped proteins. This effect was associated to the ability of these proteins to adjust to curved surfaces. The additional unfolding of proteins induced upon adsorption on scaffolds with a fibrous morphology may be the reason for better cell attachment there, promoting an easier access of cell receptors to initially hidden protein regions (e.g. RGDS sequence), which are known to have a determinant role in cell attaching processes. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Determination of Dynamics of Plant Plasma Membrane Proteins with Fluorescence Recovery and Raster Image Correlation Spectroscopy.

    Science.gov (United States)

    Laňková, Martina; Humpolíčková, Jana; Vosolsobě, Stanislav; Cit, Zdeněk; Lacek, Jozef; Čovan, Martin; Čovanová, Milada; Hof, Martin; Petrášek, Jan

    2016-04-01

    A number of fluorescence microscopy techniques are described to study dynamics of fluorescently labeled proteins, lipids, nucleic acids, and whole organelles. However, for studies of plant plasma membrane (PM) proteins, the number of these techniques is still limited because of the high complexity of processes that determine the dynamics of PM proteins and the existence of cell wall. Here, we report on the usage of raster image correlation spectroscopy (RICS) for studies of integral PM proteins in suspension-cultured tobacco cells and show its potential in comparison with the more widely used fluorescence recovery after photobleaching method. For RICS, a set of microscopy images is obtained by single-photon confocal laser scanning microscopy (CLSM). Fluorescence fluctuations are subsequently correlated between individual pixels and the information on protein mobility are extracted using a model that considers processes generating the fluctuations such as diffusion and chemical binding reactions. As we show here using an example of two integral PM transporters of the plant hormone auxin, RICS uncovered their distinct short-distance lateral mobility within the PM that is dependent on cytoskeleton and sterol composition of the PM. RICS, which is routinely accessible on modern CLSM instruments, thus represents a valuable approach for studies of dynamics of PM proteins in plants.

  1. Monitoring the diffusion behavior of Na,K-ATPase by fluorescence correlation spectroscopy (FCS) upon fluorescence labelling with eGFP or Dreiklang

    Science.gov (United States)

    Junghans, Cornelia; Schmitt, Franz-Josef; Vukojević, Vladana; Friedrich, Thomas

    2016-02-01

    Measurement of lateral mobility of membraneembedded proteins in living cells with high spatial and temporal precision is a challenging task of optofluidics. Biological membranes are complex structures, whose physico-chemical properties depend on the local lipid composition, cholesterol content and the presence of integral or peripheral membrane proteins, which may be involved in supramolecular complexes or are linked to cellular matrix proteins or the cytoskeleton. The high proteinto- lipid ratios in biomembranes indicate that membrane proteins are particularly subject to molecular crowding, making it difficult to follow the track of individual molecules carrying a fluorescence label. Novel switchable fluorescence proteins such as Dreiklang [1], are, in principle, promising tools to study the diffusion behavior of individual molecules in situations of molecular crowding due to excellent spectral control of the ON- and OFF-switching process. In this work, we expressed an integral membrane transport protein, the Na,K-ATPase comprising the human α2-subunit carrying an N-terminal eGFP or Dreiklang tag and human β1-subunit, in HEK293T cells and measured autocorrelation curves by fluorescence correlation spectroscopy (FCS). Furthermore,we measured diffusion times and diffusion constants of eGFP and Dreiklang by FCS, first, in aqueous solution after purification of the proteins upon expression in E. coli, and, second, upon expression as soluble proteins in the cytoplasm of HEK293T cells. Our data show that the diffusion behavior of the purified eGFP and Dreiklang in solution as well as the properties of the proteins expressed in the cytoplasm are very similar. However, the autocorrelation curves of eGFP- and Dreiklanglabeled Na,K-ATPase measured in the plasma membrane exhibit marked differences, with the Dreiklang-labeled construct showing shorter diffusion times. This may be related to an additional, as yet unrecognized quenching process that occurs on the same time

  2. X-ray fluorescence/Auger-electron coincidence spectroscopy of vacancy cascades in atomic argon

    International Nuclear Information System (INIS)

    Arp, U.

    1996-01-01

    Argon L 2.3 -M 2.3 M 2.3 Auger-electron spectra were measured in coincidence with Kα fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons

  3. Artificial neural networks for processing fluorescence spectroscopy data in skin cancer diagnostics

    International Nuclear Information System (INIS)

    Lenhardt, L; Zeković, I; Dramićanin, T; Dramićanin, M D

    2013-01-01

    Over the years various optical spectroscopic techniques have been widely used as diagnostic tools in the discrimination of many types of malignant diseases. Recently, synchronous fluorescent spectroscopy (SFS) coupled with chemometrics has been applied in cancer diagnostics. The SFS method involves simultaneous scanning of both emission and excitation wavelengths while keeping the interval of wavelengths (constant-wavelength mode) or frequencies (constant-energy mode) between them constant. This method is fast, relatively inexpensive, sensitive and non-invasive. Total synchronous fluorescence spectra of normal skin, nevus and melanoma samples were used as input for training of artificial neural networks. Two different types of artificial neural networks were trained, the self-organizing map and the feed-forward neural network. Histopathology results of investigated skin samples were used as the gold standard for network output. Based on the obtained classification success rate of neural networks, we concluded that both networks provided high sensitivity with classification errors between 2 and 4%. (paper)

  4. Fluorescence Correlation Spectroscopy to Study Diffusion of Polymer Chains within Layered Hydrogen-Bonded Polymer Films

    Science.gov (United States)

    Pristinski, Denis; Kharlampieva, Evguenia; Sukhishvili, Svetlana

    2002-03-01

    Fluorescence Correlation Spectroscopy (FCS) has been used to probe molecular motions within polymer multilayers formed by hydrogen-bonding sequential self-assembly. Polyethylene glycol (PEG) molecules were end-labeled with the fluorescent tags, and self-assembled with polymethacrylic acid (PMAA) using layer-by-layer deposition. We have found that molecules included in the top adsorbed layer have significant mobility at the millisecond time scale, probably due to translational diffusion. However, their dynamics deviate from classical Brownian motion with a single diffusion time. Possible reasons for the deviation are discussed. We found that motions were significantly slowed with increasing depth within the PEG/PMAA multilayer. This phenomena occured in a narrow pH range around 4.0 in which intermolecular interactions were relatively weak.

  5. Combining total internal reflection sum frequency spectroscopy spectral imaging and confocal fluorescence microscopy.

    Science.gov (United States)

    Allgeyer, Edward S; Sterling, Sarah M; Gunewardene, Mudalige S; Hess, Samuel T; Neivandt, David J; Mason, Michael D

    2015-01-27

    Understanding surface and interfacial lateral organization in material and biological systems is critical in nearly every field of science. The continued development of tools and techniques viable for elucidation of interfacial and surface information is therefore necessary to address new questions and further current investigations. Sum frequency spectroscopy (SFS) is a label-free, nonlinear optical technique with inherent surface specificity that can yield critical organizational information on interfacial species. Unfortunately, SFS provides no spatial information on a surface; small scale heterogeneities that may exist are averaged over the large areas typically probed. Over the past decade, this has begun to be addressed with the advent of SFS microscopy. Here we detail the construction and function of a total internal reflection (TIR) SFS spectral and confocal fluorescence imaging microscope directly amenable to surface investigations. This instrument combines, for the first time, sample scanning TIR-SFS imaging with confocal fluorescence microscopy.

  6. Fluorescence spectroscopy as a tool for quality assessment of humic substances

    Science.gov (United States)

    Boguta, Patrycja

    2016-04-01

    *The studies were partly carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545. Fluorescence spectroscopy belongs to modern, non-destructive, rapid and relatively cheap methods, as well as for many years it was successfully used in studies of organic compounds in the fields of medicine, biology and chemistry. On the other hand, soil organic matter is a group of compounds with a complex spatial structure showing a large number of groups with different kinds of fluorophores. This could suggest the possibility of application of fluorescence spectroscopy in assessing the quality of humic substances as well as in monitoring of their chemical transformations. The aim of study was chemical description of humic and fulvic acids based on fluorescence spectra, as well as an attempt of evaluation of changes occurring under the influence of different pH and during interactions with various concentrations of metal. The humic and fulvic acids were isolated from chemically different soils. The measurements were carried out on Hitachi fluorescence spectrometer in solutions with a concentration of humic acids 40mg dm-3, at pH from 3 to 7, and for the evaluation of the metal impact: with increasing Zn concentrations (0-50mg dm-3). The fluorescence spectra were recorded in the form of synchronous and emission-excitation matrices (EEM). Studies have shown the presence of different groups of fluorophores. Synchronous spectra were characterized by a well-separated bands showing fluorescence in the area of low, medium and high wavelengths, suggesting the presence of structures, both weakly and strongly humified. EEM spectra revealed map of fluorophores within wide ranges of emission and excitation. Fluorophores differed in both position and intensity. The highest intensity was observed for compounds with the lowest humification degree which might be due to high amount

  7. Direct Vpr-Vpr Interaction in Cells monitored by two Photon Fluorescence Correlation Spectroscopy and Fluorescence Lifetime Imaging

    Directory of Open Access Journals (Sweden)

    Mély Yves

    2008-09-01

    Full Text Available Abstract Background The human immunodeficiency virus type 1 (HIV-1 encodes several regulatory proteins, notably Vpr which influences the survival of the infected cells by causing a G2/M arrest and apoptosis. Such an important role of Vpr in HIV-1 disease progression has fuelled a large number of studies, from its 3D structure to the characterization of specific cellular partners. However, no direct imaging and quantification of Vpr-Vpr interaction in living cells has yet been reported. To address this issue, eGFP- and mCherry proteins were tagged by Vpr, expressed in HeLa cells and their interaction was studied by two photon fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy. Results Results show that Vpr forms homo-oligomers at or close to the nuclear envelope. Moreover, Vpr dimers and trimers were found in the cytoplasm and in the nucleus. Point mutations in the three α helices of Vpr drastically impaired Vpr oligomerization and localization at the nuclear envelope while point mutations outside the helical regions had no effect. Theoretical structures of Vpr mutants reveal that mutations within the α-helices could perturb the leucine zipper like motifs. The ΔQ44 mutation has the most drastic effect since it likely disrupts the second helix. Finally, all Vpr point mutants caused cell apoptosis suggesting that Vpr-mediated apoptosis functions independently from Vpr oligomerization. Conclusion We report that Vpr oligomerization in HeLa cells relies on the hydrophobic core formed by the three α helices. This oligomerization is required for Vpr localization at the nuclear envelope but not for Vpr-mediated apoptosis.

  8. Sample preparation of waste water to determine metallic contaminants by X-ray fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gonzalez Olivos, Javier.

    1987-01-01

    Trace X-ray fluorescence spectroscopy analysis in liquid samples is preceded by sample preparation, which usually consists in the precipitation of the metallic ions and concentration over a thin cellulose filter. The samples preparation of waste water by this method is not efficient, due to the great amount of organic and insoluble matter that they contain. The purpose of this work was to determine the optimal value of pH in order to adsorbe all the insoluble matter contained in a waste water sample in the activated charcoal, so that the metallic ions could be precipitated and concentrated on a thin filter and determinated by X-ray fluorescence spectroscopy. A survey about the adsorption of some ions in activated charcoal in function of the pH was made for the following: Cr 3+ , Fe 3+ , Ni 2+ , Cu 2+ , Zn 2+ , Se 2+ , Hg 2+ , and Pb 2+ . It was observed that at pH 0, the ions are not adsorbed, but Cu 2+ and Zn 2+ are adsorbed in small amount; at pH 14, the ions are adsorbed, excluding Se, which is not adsorbed at any value of pH. If a waste water sample is treated at pH 0 with activated charcoal to adsorbe the organic and insoluble matter, most of the metallic ions are not adsorbed by the activated charcoal and could be precipitated with APDC (ammonium 1-pirrolidine dithio carbamate salt) and concentrated on a thin filter. The analysis of the metallic ions contained on the filter and those adsorbed in the activated charcoal by X-ray fluorescence spectroscopy, gave the total amount of the ions in the sample. (author)

  9. High-Resolution Spectroscopy of Laser Ablation Plumes Using Laser-Induced Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; LaHaye, Nicole L.; Phillips, Mark C.

    2017-02-06

    We used a CW laser as a narrow-band (~50kHz) tunable LIF excitation source to probe absorption from selected atomic transitions (Al, U etc. ) in a ns laser ablation plume. A comparison of fluorescence signal with respect to emission spectroscopy show significant increase in the magnitude and persistence from selected Al and U transitions in a LIBS plume. The high spectral resolution provided by the LIF measurement allows peaks to be easily separated even if they overlap in the emission spectra.

  10. PyCorrFit-generic data evaluation for fluorescence correlation spectroscopy.

    Science.gov (United States)

    Müller, Paul; Schwille, Petra; Weidemann, Thomas

    2014-09-01

    We present a graphical user interface (PyCorrFit) for the fitting of theoretical model functions to experimental data obtained by fluorescence correlation spectroscopy (FCS). The program supports many data file formats and features a set of tools specialized in FCS data evaluation. The Python source code is freely available for download from the PyCorrFit web page at http://pycorrfit.craban.de. We offer binaries for Ubuntu Linux, Mac OS X and Microsoft Windows. © The Author 2014. Published by Oxford University Press.

  11. Direct measurements of neutral density depletion by two-photon absorption laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Aanesland, A.; Liard, L.; Leray, G.; Jolly, J.; Chabert, P.

    2007-01-01

    The ground state density of xenon atoms has been measured by spatially resolved laser-induced fluorescence spectroscopy with two-photon excitation in the diffusion chamber of a magnetized Helicon plasma. This technique allows the authors to directly measure the relative variations of the xenon atom density without any assumptions. A significant neutral gas density depletion was measured in the core of the magnetized plasma, in agreement with previous theoretical and experimental works. It was also found that the neutral gas density was depleted near the radial walls

  12. Fluorescent atom coincidence spectroscopy of extremely neutron-deficient barium isotopes

    International Nuclear Information System (INIS)

    Wells, S.A.; Evans, D.E.; Griffith, J.A.R.; Eastham, D.A.; Groves, J.; Smith, J.R.H.; Tolfree, D.W.L.; Warner, D.D.; Billowes, J.; Grant, I.S.; Walker, P.M.

    1988-01-01

    Fluorescent atom coincidence spectroscopy (FACS) has been used to measure the nuclear mean square radii and moments of the extremely neutron-deficient isotopes 120-124 Ba. At N=65 an abrupt change in nuclear mean square charge radii is observed which can be understood in terms of the occupation of the spin-orbit partner g 7/2 5/2[413] neutron and g 9/2 9/2[404] proton orbitals and the consequent enhancement of the n-p interaction. (orig.)

  13. Quantitative Studies of Antimicrobial Peptide Pore Formation in Large Unilamellar Vesicles by Fluorescence Correlation Spectroscopy (FCS)

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2013-01-01

    In spite of intensive research efforts over the past decades, the mechanisms by which membrane-active antimicrobial peptides interact with phospholipid membranes are not yet fully elucidated. New tools that can be used to characterize antimicrobial peptide-lipid membrane interactions are therefore...... to quantify leakage from large unilamellar vesicles is associated with a number of experimental pitfalls. Based on theoretical and experimental considerations, we discuss how to properly design experiments to avoid these pitfalls. Subsequently, we apply fluorescence correlation spectroscopy to quantify...

  14. Determination of Concentration of Living Immobilized Yeast Cells by Fluorescence Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Podrazký, Ondřej; Kuncová, Gabriela

    2005-01-01

    Roč. 107, č. 1 (2005), s. 126-134 ISSN 0925-4005. [European Conference on Optical Chemical Sensors and Biosensors EUROPT(R)ODE /7./. Madrid, 04.04.2004-07.04.2004] R&D Projects: GA ČR GA104/01/0461; GA MŠk(CZ) OC 840.10 Institutional research plan: CEZ:AV0Z40720504 Keywords : immobilization of cells * 2-D fluorescence spectroscopy * sol–gel Subject RIV: CE - Biochemistry Impact factor: 2.646, year: 2005

  15. [Discussion on diagenesis of Xilingang pluton-constrained by X-ray Fluorescence spectroscopy, plasma mass spectrometry and Raman spectroscopy].

    Science.gov (United States)

    Tang, Yu-Kun; Chen, Guo-Neng; Zhang, Ke; Huang, Hai-Hua

    2013-05-01

    The results on Xilingang pluton, mainly consisting of red beds, granites containing numerous debris of red beds and granites, obtained by X-ray fluorescence spectroscopy, plasma mass spectrometry and Raman spectroscopy show: (1) Xilingang pluton from red beds, granites containing numerous debris of red beds to granites has obvious characteristics of decreasing silicon and alkali content, and rising ignition loss, dark mineral content and oxidation index; (2) Chondrite-normalized REE distribution curves and primitive mantle-normalized spider diagram for trace elements of redbed, granites containing numerous debris of red beds and granites have a good consistency, the distribution characteristics of elements are similar to Nanling transformation-type granite; (3) The value of Raman spectrogram characteristic peak of quartz crystal in Xilingang granite decreased from the center of quartz crystal, and FWHM is steady. According to the above, the authors believe that Xilingang granite formed was related to in-situ melting of red beds and underlying strata and magma consolidation. Volatile components were discharged continuously, and oxidation index decreased gradually in the melting process. In the process of diagenesis, the top of pluton tend to be an ongoing silicon and alkali increase, while TFeO and MgO continue to migrate to bottom, and crystallization environment is a relatively closed and steady system.

  16. Dynamic fluorescence spectroscopy on single tryptophan mutants of EIImtl in detergent micelles : Effects of substrate binding and phosphorylation on the fluorescence and anisotropy decay

    NARCIS (Netherlands)

    Swaving Dijkstra, Dolf; Broos, J.; Visser, Antonie J.W.G.; van Hoek, A.; Robillard, George

    1997-01-01

    The effects of substrate and substrate analogue binding and phosphorylation on the conformational dynamics of the mannitol permease of Escherichia coli were investigated, using time-resolved fluorescence spectroscopy on mutants containing five single tryptophans situated in the membrane-embedded C

  17. Identifying changes in dissolved organic matter content and characteristics by fluorescence spectroscopy coupled with self-organizing map and classification and regression tree analysis during wastewater treatment.

    Science.gov (United States)

    Yu, Huibin; Song, Yonghui; Liu, Ruixia; Pan, Hongwei; Xiang, Liancheng; Qian, Feng

    2014-10-01

    The stabilization of latent tracers of dissolved organic matter (DOM) of wastewater was analyzed by three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy coupled with self-organizing map and classification and regression tree analysis (CART) in wastewater treatment performance. DOM of water samples collected from primary sedimentation, anaerobic, anoxic, oxic and secondary sedimentation tanks in a large-scale wastewater treatment plant contained four fluorescence components: tryptophan-like (C1), tyrosine-like (C2), microbial humic-like (C3) and fulvic-like (C4) materials extracted by self-organizing map. These components showed good positive linear correlations with dissolved organic carbon of DOM. C1 and C2 were representative components in the wastewater, and they were removed to a higher extent than those of C3 and C4 in the treatment process. C2 was a latent parameter determined by CART to differentiate water samples of oxic and secondary sedimentation tanks from the successive treatment units, indirectly proving that most of tyrosine-like material was degraded by anaerobic microorganisms. C1 was an accurate parameter to comprehensively separate the samples of the five treatment units from each other, indirectly indicating that tryptophan-like material was decomposed by anaerobic and aerobic bacteria. EEM fluorescence spectroscopy in combination with self-organizing map and CART analysis can be a nondestructive effective method for characterizing structural component of DOM fractions and monitoring organic matter removal in wastewater treatment process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Eigenvalue-eigenvector decomposition (EED) analysis of dissimilarity and covariance matrix obtained from total synchronous fluorescence spectral (TSFS) data sets of herbal preparations: Optimizing the classification approach

    Science.gov (United States)

    Tarai, Madhumita; Kumar, Keshav; Divya, O.; Bairi, Partha; Mishra, Kishor Kumar; Mishra, Ashok Kumar

    2017-09-01

    The present work compares the dissimilarity and covariance based unsupervised chemometric classification approaches by taking the total synchronous fluorescence spectroscopy data sets acquired for the cumin and non-cumin based herbal preparations. The conventional decomposition method involves eigenvalue-eigenvector analysis of the covariance of the data set and finds the factors that can explain the overall major sources of variation present in the data set. The conventional approach does this irrespective of the fact that the samples belong to intrinsically different groups and hence leads to poor class separation. The present work shows that classification of such samples can be optimized by performing the eigenvalue-eigenvector decomposition on the pair-wise dissimilarity matrix.

  19. Eigenvalue-eigenvector decomposition (EED) analysis of dissimilarity and covariance matrix obtained from total synchronous fluorescence spectral (TSFS) data sets of herbal preparations: Optimizing the classification approach.

    Science.gov (United States)

    Tarai, Madhumita; Kumar, Keshav; Divya, O; Bairi, Partha; Mishra, Kishor Kumar; Mishra, Ashok Kumar

    2017-09-05

    The present work compares the dissimilarity and covariance based unsupervised chemometric classification approaches by taking the total synchronous fluorescence spectroscopy data sets acquired for the cumin and non-cumin based herbal preparations. The conventional decomposition method involves eigenvalue-eigenvector analysis of the covariance of the data set and finds the factors that can explain the overall major sources of variation present in the data set. The conventional approach does this irrespective of the fact that the samples belong to intrinsically different groups and hence leads to poor class separation. The present work shows that classification of such samples can be optimized by performing the eigenvalue-eigenvector decomposition on the pair-wise dissimilarity matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Silicon photon-counting avalanche diodes for single-molecule fluorescence spectroscopy

    Science.gov (United States)

    Michalet, Xavier; Ingargiola, Antonino; Colyer, Ryan A.; Scalia, Giuseppe; Weiss, Shimon; Maccagnani, Piera; Gulinatti, Angelo; Rech, Ivan; Ghioni, Massimo

    2014-01-01

    Solution-based single-molecule fluorescence spectroscopy is a powerful experimental tool with applications in cell biology, biochemistry and biophysics. The basic feature of this technique is to excite and collect light from a very small volume and work in a low concentration regime resulting in rare burst-like events corresponding to the transit of a single molecule. Detecting photon bursts is a challenging task: the small number of emitted photons in each burst calls for high detector sensitivity. Bursts are very brief, requiring detectors with fast response time and capable of sustaining high count rates. Finally, many bursts need to be accumulated to achieve proper statistical accuracy, resulting in long measurement time unless parallelization strategies are implemented to speed up data acquisition. In this paper we will show that silicon single-photon avalanche diodes (SPADs) best meet the needs of single-molecule detection. We will review the key SPAD parameters and highlight the issues to be addressed in their design, fabrication and operation. After surveying the state-of-the-art SPAD technologies, we will describe our recent progress towards increasing the throughput of single-molecule fluorescence spectroscopy in solution using parallel arrays of SPADs. The potential of this approach is illustrated with single-molecule Förster resonance energy transfer measurements. PMID:25309114

  1. UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry in the diagnostics of alopecia

    Science.gov (United States)

    Skomorokha, Diana P.; Pigoreva, Yulia N.; Salmin, Vladimir V.

    2016-04-01

    Development of optical biopsy methods has a great interest for medical diagnostics. In clinical and experimental studies it is very important to analyze blood circulation quickly and accurately, thereby laser Doppler flowmetry (LDF) is widely used. UV laser-induced fluorescence spectroscopy (UV LIFS) is express highly sensitive and widely-spread method with no destructive impact, high excitation selectivity and the possibility to use in highly scattering media. The goal of this work was to assess a correlation of UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry parameters, and a possibility to identify or to differentiate various types of pathological changes in tissues according to their autofluorescence spectra. Three groups of patients with diffuse (symptomatic) alopecia, androgenic alopecia, and focal alopecia have been tested. Each groups consisted of not less than 20 persons. The measurements have been done in the parietal and occipital regions of the sculls. We used the original automated spectrofluorimeter to record autofluorescence spectra, and standard laser Doppler flowmeter BLF-21 (Transonic Systems, Inc., USA) to analyze the basal levels of blood circulation. Our results show that UV LIFS accurately distinguishes the zones with different types of alopecia. We found high correlation of the basal levels of blood circulation and the integrated intensity of autofluorescence in the affected tissue.

  2. Use of fluorescence spectroscopy to measure molecular autofluorescence in diabetic subjects

    International Nuclear Information System (INIS)

    Gomes, Cinthia Zanini

    2011-01-01

    Diabetes Mellitus (DM) comprises a complex metabolic syndrome, caused by reduced or absent secretion of insulin by pancreatic beta cells, leading to hyperglycemia. Hyperglycemia promotes glycation of proteins and, consequently, the appearance of advanced glycation end products (AGEs). Currently, diabetic patients are monitored by determining levels of glucose and glycated hemoglobin (HbA1c). The complications caused by hyperglycemia may be divided into micro and macrovascular complications, represented by retinopathy, nephropathy, neuropathy and cardiovascular disease. Albumin (HSA) is the most abundant serum protein in the human body and is subject to glycation. The Protoporphyrin IX (PpIX) is the precursor molecule of heme synthesis, structural component of hemoglobin. The in vitro and animals studies have indicated that hyperglycemia promotes a decrease in its concentration in erythrocytes. The fluorescence spectroscopy is a technique widely used in biomedical field. The autofluorescence corresponds to the intrinsic fluorescence present in some molecules, this being associated with the same structure. The aim of this study was to use fluorescence spectroscopy to measure levels of erythrocyte PpIX autofluorescence and AGE-HSA in diabetic and healthy subjects and compare them with levels of blood glucose and HbA1c. This study was conducted with 151 subjects (58 controls and 93 diabetics). Epidemiological data of patients and controls were obtained from medical records. For control subjects, blood glucose levels were obtained from medical records and levels of Hb1Ac obtained by using commercial kits. The determination of the PpIX autofluorescence was performed with excitation at 405 nm and emission at 632 nm. Determination of AGE-HSA was performed with excitation at 370 nm and emission at 455 nm. Approximately 50% of diabetic had micro and macrovascular lesions resulting from hyperglycemia. There were no significant differences in the PpIX emission intensity values

  3. Confined diffusion in tubular structures analyzed by fluorescence correlation spectroscopy on a mirror

    International Nuclear Information System (INIS)

    Etienne, Emilien; Lenne, Pierre-Francois; Sturgis, James N.; Rigneault, Herve

    2006-01-01

    In fluorescence correlation spectroscopy (FCS) analysis it is generally assumed that molecular species diffuse freely in volumes much larger than the three-dimensional FCS observation volume. However, this standard assumption is not valid in many measurement conditions, particularly in tubular structures with diameters in the micrometer range, such as those found in living cells (organelles, dendrites) and microfluidic devices (capillaries,reaction chambers). As a result the measured autocorrelation functions (ACFs) deviate from those predicted for free diffusion, and this can shift the measured diffusion coefficient by as much as ∼50% when the tube diameter is comparable with the axial extension of the FCS observation volume. We show that the range of validity of the FCS measurements can be drastically improved if the tubular structures are located in the close vicinity of a mirror on which FCS is performed. In this case a new fluctuation time in the ACF, arising from the diffusion of fluorescent probes in optical fringes,permits measurement of the real diffusion coefficient within the tubular structure without assumptions about either the confined geometry orthe FCS observation volume geometry. We show that such a measurement can be done when the tubular structure contains at least one pair of dark and bright fringes resulting from interference between the incoming and the reflected excitation beams on the mirror surface. Measurement of the diffusion coefficient of the enhanced green fluorescent protein (EGFP) and IscS-EGFP in the cytoplasm of living Escherichiacoli illustrates the capabilities of the technique

  4. Pancreatic tumor detection using hypericin-based fluorescence spectroscopy and cytology

    Science.gov (United States)

    Lavu, Harish; Geary, Kevin; Fetterman, Harold R.; Saxton, Romaine E.

    2005-04-01

    Hypericin is a novel, highly fluorescent photosensitizer that exhibits selective tumor cell uptake properties and is particularly resistant to photobleaching. In this study, we have characterized hypericin uptake in human pancreatic tumor cells with relation to incubation time, cell number, and drug concentration. Ex vivo hypericin based fluorescence spectroscopy was performed to detect the presence of MIA PaCa-2 pancreatic tumor cells in the peritoneal cavity of BALB/c nude mice, as well as to quantify gross tumor burden. Hypericin based cytology of peritoneal lavage samples, using both one and two photon laser confocal microscopy, demonstrated more than a two-fold increase in fluorescence emission of pancreatic tumor cells as compared to control samples. In vitro treatment of pancreatic cancer cells with hypericin based photodynamic therapy showed tumor cell cytotoxicity in a drug dose, incident laser power, and time dependent manner. For these experiments, a continuous wavelength solid-state laser source (532 nm) was operated at power levels in the range of 100-400 mW. Potential applications of hypericin in tumor diagnosis, staging, and therapy will be presented.

  5. Spatially resolved x-ray fluorescence spectroscopy of beryllium capsule implosions at the NIF

    Science.gov (United States)

    MacDonald, M. J.; Bishel, D. T.; Saunders, A. M.; Scott, H. A.; Kyrala, G.; Kline, J.; MacLaren, S.; Thorn, D. B.; Yi, S. A.; Zylstra, A. B.; Falcone, R. W.; Doeppner, T.

    2017-10-01

    Beryllium ablators used in indirectly driven inertial confinement fusion implosions are doped with copper to prevent preheat of the cryogenic hydrogen fuel. Here, we present analysis of spatially resolved copper K- α fluorescence spectra from the beryllium ablator layer. It has been shown that K- α fluorescence spectroscopy can be used to measure plasma conditions of partially ionized dopants in high energy density systems. In these experiments, K-shell vacancies in the copper dopant are created by the hotspot emission at stagnation, resulting in K-shell fluorescence at bang time. Spatially resolved copper K- α emission spectra are compared to atomic kinetics and radiation code simulations to infer density and temperature profiles. This work was supported by the US DOE under Grant No. DE-NA0001859, under the auspices of the US DOE by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344, and by Los Alamos National Laboratory under contract DE-AC52-06NA52396.

  6. Assessment of post-implantation integration of engineered tissues using fluorescence lifetime spectroscopy

    Science.gov (United States)

    Elahi, Sakib F.; Lee, Seung Y.; Lloyd, William R.; Chen, Leng-Chun; Kuo, Shiuhyang; Zhou, Ying; Kim, Hyungjin M.; Kennedy, Robert; Marcelo, Cynthia; Feinberg, Stephen E.; Mycek, Mary-Ann

    2018-02-01

    Clinical translation of engineered tissue constructs requires noninvasive methods to assess construct health and viability after implantation in patients. However, current practices to monitor post-implantation construct integration are either qualitative (visual assessment) or destructive (tissue histology). As label-free fluorescence lifetime sensing can noninvasively characterize pre-implantation construct viability, we employed a handheld fluorescence lifetime spectroscopy probe to quantitatively and noninvasively assess tissue constructs that were implanted in a murine model. We designed the system to be suitable for intravital measurements: portability, localization with precise maneuverability, and rapid data acquisition. Our model tissue constructs were manufactured from primary human cells to simulate patient variability and were stressed to create a range of health states. Secreted amounts of three cytokines that relate to cellular viability were measured in vitro to assess pre-implantation construct health. In vivo optical sensing assessed tissue integration of constructs at one-week and three-weeks post-implantation. At one-week post-implantation, optical parameters correlated with in vitro pre-implantation secretion levels of all three cytokines (p clinical optical diagnostic tools based on label-free fluorescence lifetime sensing of endogenous tissue fluorophores could noninvasively monitor post-implantation integration of engineered tissues.

  7. Probing GFP-actin diffusion in living cells using fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Engelke, Hanna; Heinrich, Doris; Rädler, Joachim O.

    2010-01-01

    The cytoskeleton of eukaryotic cells is continuously remodeled by polymerization and depolymerization of actin. Consequently, the relative content of polymerized filamentous actin (F-actin) and monomeric globular actin (G-actin) is subject to temporal and spatial fluctuations. Since fluorescence correlation spectroscopy (FCS) can measure the diffusion of fluorescently labeled actin it seems likely that FCS allows us to determine the dynamics and hence indirectly the structural properties of the cytoskeleton components with high spatial resolution. To this end we investigate the FCS signal of GFP-actin in living Dictyostelium discoideum cells and explore the inherent spatial and temporal signatures of the actin cytoskeleton. Using the free green fluorescent protein (GFP) as a reference, we find that actin diffusion inside cells is dominated by G-actin and slower than diffusion in diluted cell extract. The FCS signal in the dense cortical F-actin network near the cell membrane is probed using the cytoskeleton protein LIM and is found to be slower than cytosolic G-actin diffusion. Furthermore, we show that polymerization of the cytoskeleton induced by Jasplakinolide leads to a substantial decrease of G-actin diffusion. Pronounced fluctuations in the distribution of the FCS correlation curves can be induced by latrunculin, which is known to induce actin waves. Our work suggests that the FCS signal of GFP-actin in combination with scanning or spatial correlation techniques yield valuable information about the local dynamics and concomitant cytoskeletal properties

  8. Fluorescence correlation spectroscopy and fluorescence cross-correlation spectroscopy reveal the cytoplasmic origination of loaded nuclear RISC in vivo in human cells.

    Science.gov (United States)

    Ohrt, Thomas; Mütze, Jörg; Staroske, Wolfgang; Weinmann, Lasse; Höck, Julia; Crell, Karin; Meister, Gunter; Schwille, Petra

    2008-11-01

    Studies of RNA interference (RNAi) provide evidence that in addition to the well-characterized cytoplasmic mechanisms, nuclear mechanisms also exist. The mechanism by which the nuclear RNA-induced silencing complex (RISC) is formed in mammalian cells, as well as the relationship between the RNA silencing pathways in nuclear and cytoplasmic compartments is still unknown. Here we show by applying fluorescence correlation and cross-correlation spectroscopy (FCS/FCCS) in vivo that two distinct RISC exist: a large approximately 3 MDa complex in the cytoplasm and a 20-fold smaller complex of approximately 158 kDa in the nucleus. We further show that nuclear RISC, consisting only of Ago2 and a short RNA, is loaded in the cytoplasm and imported into the nucleus. The loaded RISC accumulates in the nucleus depending on the presence of a target, based on an miRNA-like interaction with impaired cleavage of the cognate RNA. Together, these results suggest a new RISC shuttling mechanism between nucleus and cytoplasm ensuring concomitant gene regulation by small RNAs in both compartments.

  9. A novel approach for the detection of early gastric cancer: fluorescence spectroscopy of gastric juice.

    Science.gov (United States)

    Deng, Kai; Zhou, Li Ya; Lin, San Ren; Li, Yuan; Chen, Mo; Geng, Qiu Ming; Li, Yu Wen

    2013-06-01

    This study aimed to investigate the efficacy of fluorescence spectroscopy of gastric juice for early gastric cancer (EGC) screening. Gastric juice was collected from 101 participants who underwent endoscopy in the Outpatient Endoscopy Center of Peking University Third Hospital. The participants were divided into three groups: the normal mucosa or chronic non-atrophic gastritis (NM-CNAG) group (n = 35), advanced gastric cancer (AGC) group (n = 33) and EGC group (n = 33). Fluorescence spectroscopic analysis was performed in all the gastric juice samples and the maximum fluorescence intensity of the first peak (P1 FI) was measured. The mean fluorescence intensity of P1 FI of gastric juice in AGC (92.1 ± 10.7) and EGC (90.8 ± 12.0) groups was significantly higher than that in the NM-CNAG group (55.7 ± 7.5) (AGC vs NM-CNAG, P = 0.006 and EGC vs NM-CNAG, P = 0.015, respectively). The areas under the receiver operating characteristic curves for the detection of AGC and EGC were 0.681 (95% confidence interval [CI] 0.553-0.810, P = 0.010) and 0.655 (95% CI 0.522-0.787, P = 0.028). With the P1 FI of ≥47.7, the sensitivity, specificity and accuracy for detecting EGC were 69.7%, 57.1% and 63.2%, respectively. The enhancement of P1 FI of gastric juice occurs at the early stage of gastric cancer. Fluorescence spectroscopy of gastric juice may be used as a novel screening tool for the early detection of gastric cancer. © 2013 The Authors. Journal of Digestive Diseases © 2013 Wiley Publishing Asia Pty Ltd and Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.

  10. Self-Aggregation in Pyrrole:  Matrix Isolation, Solid State Infrared Spectroscopy, and DFT Study

    OpenAIRE

    Gómez-Zavaglia, Andrea; Fausto, Rui

    2004-01-01

    Pyrrole (C4H5N) was embedded in low-temperature solid inert matrixes (argon, xenon; T = 9 K) and both the monomer and low-order aggregates characterized by FTIR spectroscopy. The spectroscopic studies were complemented by extensive theoretical [DFT(B3LYP)/6-311++G(d,p)] structural and vibrational studies carried out for the monomer and their self-aggregates (up to four units). The calculated spectrum for monomeric pyrrole fits well those obtained immediately after deposition (at 9 K) of dilut...

  11. Matrix isolation FT-IR spectroscopy and molecular orbital study of sarcosine methyl ester

    OpenAIRE

    Gómez-Zavaglia, Andrea; Fausto, R.

    2004-01-01

    N-methylglycine methyl ester (sarcosine-Me) has been studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d,p) and 6-31++G(d,p) basis set, respectively. Twelve different conformers were located in the potential energy surface of the studied compound, with the ASC conformer being the ground conformational state. This form is analogous to the dimethylglycine methyl ester most stable conformer and...

  12. Statistical Analysis of Bending Rigidity Coefficient Determined Using Fluorescence-Based Flicker-Noise Spectroscopy.

    Science.gov (United States)

    Doskocz, Joanna; Drabik, Dominik; Chodaczek, Grzegorz; Przybyło, Magdalena; Langner, Marek

    2018-06-01

    Bending rigidity coefficient describes propensity of a lipid bilayer to deform. In order to measure the parameter experimentally using flickering noise spectroscopy, the microscopic imaging is required, which necessitates the application of giant unilamellar vesicles (GUV) lipid bilayer model. The major difficulty associated with the application of the model is the statistical character of GUV population with respect to their size and the homogeneity of lipid bilayer composition, if a mixture of lipids is used. In the paper, the bending rigidity coefficient was measured using the fluorescence-enhanced flicker-noise spectroscopy. In the paper, the bending rigidity coefficient was determined for large populations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine vesicles. The quantity of obtained experimental data allows to perform statistical analysis aiming at the identification of the distribution, which is the most appropriate for the calculation of the value of the membrane bending rigidity coefficient. It has been demonstrated that the bending rigidity coefficient is characterized by an asymmetrical distribution, which is well approximated with the gamma distribution. Since there are no biophysical reasons for that we propose to use the difference between normal and gamma fits as a measure of the homogeneity of vesicle population. In addition, the effect of a fluorescent label and types of instrumental setups on determined values has been tested. Obtained results show that the value of the bending rigidity coefficient does not depend on the type of a fluorescent label nor on the type of microscope used.

  13. Total reflection x-ray fluorescence spectroscopy as a tool for evaluation of iron concentration in ferrofluids and yeast samples

    Energy Technology Data Exchange (ETDEWEB)

    Kulesh, N.A., E-mail: nikita.kulesh@urfu.ru [Ural Federal University, Mira 19, 620002 Ekaterinburg (Russian Federation); Novoselova, I.P. [Ural Federal University, Mira 19, 620002 Ekaterinburg (Russian Federation); Immanuel Kant Baltic Federal University, 236041 Kaliningrad (Russian Federation); Safronov, A.P. [Ural Federal University, Mira 19, 620002 Ekaterinburg (Russian Federation); Institute of Electrophysics UD RAS, Amundsen 106, 620016 Ekaterinburg (Russian Federation); Beketov, I.V.; Samatov, O.M. [Institute of Electrophysics UD RAS, Amundsen 106, 620016 Ekaterinburg (Russian Federation); Kurlyandskaya, G.V. [Ural Federal University, Mira 19, 620002 Ekaterinburg (Russian Federation); University of the Basque Country UPV-EHU, 48940 Leioa (Spain); Morozova, M. [Ural Federal University, Mira 19, 620002 Ekaterinburg (Russian Federation); Denisova, T.P. [Irkutsk State University, Karl Marks 1, 664003 Irkutsk (Russian Federation)

    2016-10-01

    In this study, total reflection x-ray fluorescent (TXRF) spectrometry was applied for the evaluation of iron concentration in ferrofluids and biological samples containing iron oxide magnetic nanoparticles obtained by the laser target evaporation technique. Suspensions of maghemite nanoparticles of different concentrations were used to estimate the limitation of the method for the evaluation of nanoparticle concentration in the range of 1–5000 ppm in absence of organic matrix. Samples of single-cell yeasts grown in the nutrient media containing maghemite nanoparticles were used to study the nanoparticle absorption mechanism. The obtained results were analyzed in terms of applicability of TXRF for quantitative analysis in a wide range of iron oxide nanoparticle concentrations for biological samples and ferrofluids with a simple established protocol of specimen preparation. - Highlights: • Ferrofluids and yeasts samples were analysed by TXRF spectroscopy. • Simple protocol for iron quantification by means of TXRF was proposed. • Results were combined with magnetic, structural, and morphological characterization. • Preliminary conclusion on nanoparticles uptake mechanism was made.

  14. Total reflection x-ray fluorescence spectroscopy as a tool for evaluation of iron concentration in ferrofluids and yeast samples

    International Nuclear Information System (INIS)

    Kulesh, N.A.; Novoselova, I.P.; Safronov, A.P.; Beketov, I.V.; Samatov, O.M.; Kurlyandskaya, G.V.; Morozova, M.; Denisova, T.P.

    2016-01-01

    In this study, total reflection x-ray fluorescent (TXRF) spectrometry was applied for the evaluation of iron concentration in ferrofluids and biological samples containing iron oxide magnetic nanoparticles obtained by the laser target evaporation technique. Suspensions of maghemite nanoparticles of different concentrations were used to estimate the limitation of the method for the evaluation of nanoparticle concentration in the range of 1–5000 ppm in absence of organic matrix. Samples of single-cell yeasts grown in the nutrient media containing maghemite nanoparticles were used to study the nanoparticle absorption mechanism. The obtained results were analyzed in terms of applicability of TXRF for quantitative analysis in a wide range of iron oxide nanoparticle concentrations for biological samples and ferrofluids with a simple established protocol of specimen preparation. - Highlights: • Ferrofluids and yeasts samples were analysed by TXRF spectroscopy. • Simple protocol for iron quantification by means of TXRF was proposed. • Results were combined with magnetic, structural, and morphological characterization. • Preliminary conclusion on nanoparticles uptake mechanism was made.

  15. A reduced graphene oxide-based fluorescence resonance energy transfer sensor for highly sensitive detection of matrix metalloproteinase 2.

    Science.gov (United States)

    Xi, Gaina; Wang, Xiaoping; Chen, Tongsheng

    2016-01-01

    A novel fluorescence nanoprobe (reduced nano-graphene oxide [nrGO]/fluorescein isothiocyanate-labeled peptide [Pep-FITC]) for ultrasensitive detection of matrix metalloproteinase 2 (MMP2) has been developed by engineering the Pep-FITC comprising the specific MMP2 substrate domain (PLGVR) onto the surface of nrGO particles through non-covalent linkage. The nrGO was obtained by water bathing nano-graphene oxide under 90°C for 4 hours. After mixing the nrGO and Pep-FITC for 30 seconds, the fluorescence from Pep-FITC was almost completely quenched due to the fluorescence resonance energy transfer between fluorescein isothiocyanate (FITC) and nrGO. Upon cleavage of the amide bond between Leu and Gly in the Pep-FITC by protease-MMP2, the FITC bound to nrGO was separated from nrGO surface, disrupting the fluorescence resonance energy transfer process and resulting in fluorescence recovery of FITC. Under optimal conditions, the fluorescence recovery of nrGO/Pep-FITC was found to be directly proportional to the concentration of MMP2 within 0.02-0.1 nM. The detection limit of the nrGO/Pep-FITC was determined to be 3 pM, which is approximately tenfold lower than that of the unreduced carboxylated nano-graphene oxide/Pep-FITC probe.

  16. Chemometric classification of Chinese lager beers according to manufacturer based on data fusion of fluorescence, UV and visible spectroscopies.

    Science.gov (United States)

    Tan, Jin; Li, Rong; Jiang, Zi-Tao

    2015-10-01

    We report an application of data fusion for chemometric classification of 135 canned samples of Chinese lager beers by manufacturer based on the combination of fluorescence, UV and visible spectroscopies. Right-angle synchronous fluorescence spectra (SFS) at three wavelength difference Δλ=30, 60 and 80 nm and visible spectra in the range 380-700 nm of undiluted beers were recorded. UV spectra in the range 240-400 nm of diluted beers were measured. A classification model was built using principal component analysis (PCA) and linear discriminant analysis (LDA). LDA with cross-validation showed that the data fusion could achieve 78.5-86.7% correct classification (sensitivity), while those rates using individual spectroscopies ranged from 42.2% to 70.4%. The results demonstrated that the fluorescence, UV and visible spectroscopies complemented each other, yielding higher synergic effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. FT-Raman spectroscopy study of organic matrix degradation in nanofilled resin composite.

    Science.gov (United States)

    Soares, Luís Eduardo Silva; Nahórny, Sídnei; Martin, Airton Abrahão

    2013-04-01

    This in vitro study evaluated the effect of light curing unit (LCU) type, mouthwashes, and soft drink on chemical degradation of a nanofilled resin composite. Samples (80) were divided into eight groups: halogen LCU, HS--saliva (control); HPT--Pepsi Twist®; HLC--Listerine®; HCP--Colgate Plax®; LED LCU, LS--saliva (control); LPT--Pepsi Twist®; LLC--Listerine®; LCP--Colgate Plax®. The degree of conversion analysis and the measure of the peak area at 2,930 cm-1 (organic matrix) of resin composite were done by Fourier-transform Raman spectroscopy (baseline, after 7 and 14 days). The data were subjected to multifactor analysis of variance (ANOVA) at a 95% confidence followed by Tukey's HSD post-hoc test. The DC ranged from 58.0% (Halogen) to 59.3% (LED) without significance. Differences in the peak area between LCUs were found after 7 days of storage in S and PT. A marked increase in the peak intensity of HLC and LLC groups was found. The soft-start light-activation may influence the chemical degradation of organic matrix in resin composite. Ethanol contained in Listerine® Cool Mint mouthwash had the most significant degradation effect. Raman spectroscopy is shown to be a useful tool to investigate resin composite degradation.

  18. Combined fluorescence-Raman spectroscopy measurements with an optical fiber probe for the diagnosis of melanocytic lesions

    Science.gov (United States)

    Cosci, Alessandro; Cicchi, Riccardo; Rossari, Susanna; De Giorgi, Vincenzo; Massi, Daniela; Pavone, Francesco S.

    2012-02-01

    We have designed and developed an optical fiber-probe for spectroscopic measurements on human tissues. The experimental setup combines fluorescence spectroscopy and Raman spectroscopy in a multidimensional approach. Concerning fluorescence spectroscopy, the excitation is provided by two laser diodes, one emitting in the UV (378 nm) and the other emitting in the visible (445 nm). These two lasers are used to selectively excite fluorescence from NADH and FAD, which are among the brightest endogenous fluorophores in human tissues. For Raman and NIR spectroscopy, the excitation is provided by a third laser diode with 785 nm excitation wavelength. Laser light is delivered to the tissue through the central optical fiber of a fiber bundle. The surrounding 48 fibers of the bundle are used for collecting fluorescence and Raman and for delivering light to the spectrograph. Fluorescence and Raman spectra are acquired on a cooled CCD camera. The instrument has been tested on fresh human skin biopsies clinically diagnosed as malignant melanoma, melanocytic nevus, or healthy skin, finding an optimal correlation with the subsequent histological exam. In some cases our examination was not in agreement with the clinical observation, but it was with the histological exam, demonstrating that the system can potentially contribute to improve clinical diagnostic capabilities and hence reduce the number of unnecessary biopsies.

  19. Steady state and time-resolved fluorescence spectroscopy of quinine sulfate dication bound to sodium dodecylsulfate micelles: Fluorescent complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Sunita; Pant, Debi D., E-mail: ddpant@pilani.bits-pilani.ac.in

    2014-01-15

    Interaction of quinine sulfate dication (QSD) with anionic, sodium dodecylsulphate (SDS) surfactant has been studied at different premicellar, micellar and postmicellar concentrations in aqueous phase using steady state, time-resolved fluorescence and fluorescence anisotropy techniques. At premicellar concentrations of SDS, the decrease in absorbance, appearance of an extra fluorescence band at lower wavelengths and tri-exponential decay behavior of fluorescence, are attributed to complex formation between QSD molecules and surfactant monomers. At postmicellar concentrations the red shift in fluorescence spectrum, increase in quantum yield and increase in fluorescence lifetimes are attributed to incorporation of solute molecules to micelles. At lower concentrations of SDS, a large shift in fluorescence is observed on excitation at the red edge of absorption spectrum and this is explained in terms of distribution of ion pairs of different energies in the ground state and the observed fluorescence lifetime behavior corroborates with this model. The temporal fluorescence anisotropy decay of QSD in SDS micelles allowed determination of restriction on the motion of the fluorophore. All the different techniques used in this study reveal that the photophysics of QSD is very sensitive to the microenvironments of SDS micelles and QSD molecules reside at the water-micelle interface. -- Highlights: • Probe molecule is very sensitive to microenvironment of micelles. • Highly fluorescent ion-pair formation has been observed. • Modulated photophysics of probe molecule in micellar solutions has been observed. • Probe molecules strongly bind with micelles and reside at probe–micelle interface.

  20. Accessibility of nucleic acid-complexed biomolecules to hydroxyl radicals correlates with their conformation: a fluorescence polarization spectroscopy study

    International Nuclear Information System (INIS)

    Makrigiorgos, G.M.; Bump, E.; Huang, C.; Kassis, A.I.; Baranowska-Kortylewicz, J.

    1994-01-01

    A fluorescence methodology has been developed to examine the relationship between the conformational state of specific biomolecules in simple chromatin models and their accessibility to hydroxyl radicals ( . OH). Polylysine and histone H1 were labelled with SECCA, the succinimidyl ester of coumarin-3-carboxylic acid, which generates the fluorescent derivative 7-OH-SECCA following its interaction with radiation-induced . OH in aqueous solution. The fluorescence induced per unit γ-ray dose reflecting the accessibility of . OH to such SECCA-conjugated biomolecules was recorded. The biomolecules were also labelled with the fluorescent derivative 7-OH-SECCA in trace amounts to study their conformation under identical conditions via fluorescence polarization spectroscopy. (author)

  1. The Effect of a Fluorophore Photo-Physics on the Lipid Vesicle Diffusion Coefficient Studied by Fluorescence Correlation Spectroscopy.

    Science.gov (United States)

    Drabik, Dominik; Przybyło, Magda; Sikorski, Aleksander; Langner, Marek

    2016-03-01

    Fluorescence Correlation Spectroscopy (FCS) is a technique, which allows determination of the diffusion coefficient and concentration of fluorescent objects suspended in the solution. The measured parameter is the fluctuation of the fluorescence signal emitted by diffusing molecules. When 100 nm DOPC vesicles labeled with various fluorescent dyes (Fluorescein-PE, NBD-PE, Atto488 DOPE or βBodipy FL) were measured, different values of diffusion coefficients have been obtained. These diffusion coefficients were different from the expected values measured using the dynamic light scattering method (DLS). The FCS was initially developed for solutions containing small fluorescent molecules therefore the observed inconsistency may result from the nature of vesicle suspension itself. The duration of the fluorescence signal may depend on the following factors: the exposure time of the labeled object to the excitation beam, the photo-physical properties (e.g., stability) of a fluorophore, the theoretical model used for the calculations of the diffusion coefficient and optical properties of the vesicle suspension. The diffusion coefficients determined for differently labeled liposomes show that its dependence on vesicle size and quantity of fluorescent probed used for labeling was significant demonstrating that the fluorescence properties of the fluorophore itself (bleaching and/or blinking) were critical factors for a correct outcome of FCS experiment. The new, based on combined FCS and DLS measurements, method for the determination of the focal volume prove itself to be useful for the evaluation of a fluorescence dye with respect to its applicability for FCS experiment.

  2. Comparison of nanoparticle diffusion using fluorescence correlation spectroscopy and differential dynamic microscopy within concentrated polymer solutions

    Science.gov (United States)

    Shokeen, Namita; Issa, Christopher; Mukhopadhyay, Ashis

    2017-12-01

    We studied the diffusion of nanoparticles (NPs) within aqueous entangled solutions of polyethylene oxide (PEO) by using two different optical techniques. Fluorescence correlation spectroscopy, a method widely used to investigate nanoparticle dynamics in polymer solution, was used to measure the long-time diffusion coefficient (D) of 25 nm radius particles within high molecular weight, Mw = 600 kg/mol PEO in water solutions. Differential dynamic microscopy (DDM) was used to determine the wave-vector dependent dynamics of NPs within the same polymer solutions. Our results showed good agreement between the two methods, including demonstration of normal diffusion and almost identical diffusion coefficients obtained by both techniques. The research extends the scope of DDM to study the dynamics and rheological properties of soft matter at a nanoscale. The measured diffusion coefficients followed a scaling theory, which can be explained by the coupling between polymer dynamics and NP motion.

  3. Probing the photoluminescence properties of gold nanoclusters by fluorescence lifetime correlation spectroscopy

    International Nuclear Information System (INIS)

    Yuan, C. T.; Lin, T. N.; Shen, J. L.; Lin, C. A.; Chang, W. H.; Cheng, H. W.; Tang, J.

    2013-01-01

    Gold nanoclusters (Au NCs) have attracted much attention for promising applications in biological imaging owing to their tiny sizes and biocompatibility. So far, most efforts have been focused on the strategies for fabricating high-quality Au NCs and then characterized by conventional ensemble measurement. Here, a fusion single-molecule technique combining fluorescence correlation spectroscopy and time-correlated single-photon counting can be successfully applied to probe the photoluminescence (PL) properties for sparse Au NCs. In this case, the triplet-state dynamics and diffusion process can be observed simultaneously and the relevant time constants can be derived. This work provides a complementary insight into the PL mechanism at the molecular levels for Au NCs in solution

  4. Confined detection volume of fluorescence correlation spectroscopy by bare fiber probes.

    Science.gov (United States)

    Lu, Guowei; Lei, Franck H; Angiboust, Jean-François; Manfait, Michel

    2010-04-01

    A fiber-tip-based near-field fluorescence correlation spectroscopy (FCS) has been developed for confining the detection volume to sub-diffraction-limited dimensions. This near-field FCS is based on near-field illumination by coupling a scanning near-field optical microscope (SNOM) to a conventional confocal FCS. Single-molecule FCS analysis at 100 nM Rhodamine 6G has been achieved by using bare chemically etched, tapered fiber tips. The detection volume under control of the SNOM system has been reduced over one order of magnitude compared to that of the conventional confocal FCS. Related factors influencing the near-field FCS performance are investigated and discussed in detail. In this proof-of-principle study, the preliminary experimental results suggest that the fiber-tip-based near-field FCS might be a good alternative to realize localized analysis at the single-molecule level.

  5. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we obta...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz.......We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...

  6. Fluorescence and NMR spectroscopy together with molecular simulations reveal amphiphilic characteristics of a Burkholderia biofilm exopolysaccharide.

    Science.gov (United States)

    Kuttel, Michelle M; Cescutti, Paola; Distefano, Marco; Rizzo, Roberto

    2017-06-30

    Biofilms are a collective mode of bacterial life in which a self-produced matrix confines cells in close proximity to each other. Biofilms confer many advantages, including protection from chemicals (including antibiotics), entrapment of useful extracellular enzymes and nutrients, as well as opportunities for efficient recycling of molecules from dead cells. Biofilm matrices are aqueous gel-like structures composed of polysaccharides, proteins, and DNA stabilized by intermolecular interactions that may include non-polar connections. Recently, polysaccharides extracted from biofilms produced by species of the Burkholderia cepacia complex were shown to possess clusters of rhamnose, a 6-deoxy sugar with non-polar characteristics. Molecular dynamics simulations are well suited to characterizing the structure and dynamics of polysaccharides, but only relatively few such studies exist of their interaction with non-polar molecules. Here we report an investigation into the hydrophobic properties of the exopolysaccharide produced by Burkholderia multivorans strain C1576. Fluorescence experiments with two hydrophobic fluorescent probes established that this polysaccharide complexes hydrophobic species, and NMR experiments confirmed these interactions. Molecular simulations to model the hydrodynamics of the polysaccharide and the interaction with guest species revealed a very flexible, amphiphilic carbohydrate chain that has frequent dynamic interactions with apolar molecules; both hexane and a long-chain fatty acid belonging to the quorum-sensing system of B. multivorans were tested. A possible role of the non-polar domains of the exopolysaccharide in facilitating the diffusion of aliphatic species toward specific targets within the biofilm aqueous matrix is proposed. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. [Vermicomposting of different organic materials and three-dimensional excitation emission matrix fluorescence spectroscopic characterization of their dissolved organic matter].

    Science.gov (United States)

    Yang, Wei; Wang, Dong-sheng; Liu, Man-qiang; Hu, Feng; Li, Hui-xin; Huang, Zhong-yang; Chang, Yi-jun; Jiao, Jia-guo

    2015-10-01

    In this experiment, different proportions of the cattle manure, tea-leaf, herb and mushroom residues, were used as food for earthworm (Eisenia fetida) to study the growth of the earth-worm. Then the characteristics and transformation of nutrient content and three-dimensional excitation emission matrix fluorescence (3DEEM) of dissolved organic matter (DOM) during vermistabilization were investigated by means of chemical and spectroscopic methods. The result showed that the mixture of different ratios of cattle manure with herb residue, and cattle manure with tea-leaf were conducive to the growth of earthworm, while the materials compounded with mushroom residue inhibited the growth of earthworm. With the increasing time of verimcomposting, the pH in vermicompost tended to be circumneutral and weakly acidic, and there were increases in electrical conductivity, and the contents of total nitrogen, total phosphorus, available nitrogen, and available phosphorus, while the total potassium and available potassium increased first and then decreased, and the organic matter content decreased. 3DEEM and fluorescence regional integration results indicated that, the fluorescence of protein-like fluorescence peaks declined significantly, while the intensity of humic-like fluorescence peak increased significantly in DOM. Vermicomposting process might change the compositions of DOM with elevated concentrations of humic acid and fulvic acid in the organics. In all, this study suggested the suitability of 3DEEM for monitoring the organics transformation and assessing the maturity in the vermicomposting.

  8. Detection of rhodopsin dimerization in situ by PIE-FCCS, a time-resolved fluorescence spectroscopy.

    Science.gov (United States)

    Smith, Adam W

    2015-01-01

    Rhodopsin self-associates in the plasma membrane. At low concentrations, the interactions are consistent with a monomer-dimer equilibrium (Comar et al., J Am Chem Soc 136(23):8342-8349, 2014). At high concentrations in native tissue, higher-order clusters have been observed (Fotiadis et al., Nature 421:127-128, 2003). The physiological role of rhodopsin dimerization is still being investigated, but it is clear that a quantitative assessment is essential to determining the function of rhodopsin clusters in vision. To quantify rhodopsin interactions, I will outline the theory and methodology of a specialized time-resolved fluorescence spectroscopy for measuring membrane protein-protein interactions called pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). The strength of this technique is its ability to quantify rhodopsin interactions in situ (i.e., a live cell plasma membrane). There are two reasons for restricting the scope to live cell membranes. First, the compositional heterogeneity of the plasma membrane creates a complex milieu with thousands of lipid, protein, and carbohydrate species. This makes it difficult to infer quaternary interactions from detergent solubilized samples or construct a model phospholipid bilayer that recapitulates all of the interactions present in native membranes. Second, organizational structure and dynamics is a key feature of the plasma membrane, and fixation techniques like formaldehyde cross-linking and vitrification will modulate the interactions. PIE-FCCS is based on two-color fluorescence imaging with time-correlated single-photon counting (TCSPC) (Becker et al., Rev Sci Instrum 70:1835-1841, 1999). By time-tagging every detected photon, the data can be analyzed as a fluorescence intensity distribution, fluorescence lifetime histogram, or fluorescence (cross-)correlation spectra (FCS/FCCS) (Becker, Advanced time-correlated single-photon counting techniques, Springer, Berlin, 2005). These

  9. Optical diagnostic of breast cancer using Raman, polarimetric and fluorescence spectroscopy

    Science.gov (United States)

    Anwar, Shahzad; Firdous, Shamaraz; Rehman, Aziz-ul; Nawaz, Muhammed

    2015-04-01

    We presented the optical diagnostic of normal and cancerous human breast tissues using Raman, polarimetric and fluorescence spectroscopic techniques. Breast cancer is the second leading cause of cancer death among women worldwide. Optical diagnostics of cancer offered early intervention and the greatest chance of cure. Spectroscopic data were collected from freshly excised surgical specimens of normal tissues with Raman bands at 800, 1171 and 1530 cm-1 arising mainly by lipids, nucleic acids, proteins, carbohydrates and amino acids. For breast cancer, Raman bands are observed at 1070, 1211, 1495, 1583 and 1650 cm-1. Results demonstrate that the spectra of normal tissue are dominated by lipids and amino acids. Polarization decomposition of the Mueller matrix and confocal microscopic fluorescence provides detailed description of cancerous tissue and distinguishes between the normal and malignant one. Based on these findings, we successfully differentiate normal and malignant breast tissues at an early stage of disease. There is a need to develop a new tool for noninvasive, real-time diagnosis of tissue abnormalities and a test procedure for detecting breast cancer at an early stage.

  10. X-ray fluorescence spectroscopy technology applied to the materials elementary characterization

    International Nuclear Information System (INIS)

    Marambio A, Cristian Gilberto.

    1997-01-01

    A thorough study of the different applications of energy dispersive x-ray fluorescence spectrometry is presented, using different excitation sources and measurement geometries. The adaptation of these systems focuses on the analytical solution for different sample types by studying distinct parameters such as: volume of saturation for liquid samples, inter elemental effects from the matrix and the interferences associated with the measurement reading statistical parameters: as reproducibility, precision and detection limits. The application of the technique using radioisotopic sources gave satisfactory results in the analysis of geologic samples, in analytical control of concentration processes for rare earths and for the manufacturing of fuel elements. In the case of a system with an x-ray generator two measurement geometries were studied: 45 deg geometry and total reflection. There were major results in the analysis of polymer impurities and alloy impurities, aluminums and thin semiconductor films, respectively, after non destructive in situ analysis of the material. The results show that x-ray fluorescence spectrometry is a powerful tool for analysis and process control, with prospects for the solution of analytical problems in the materials area. (author)

  11. Fluorescence Spectroscopy Applied to Monitoring Biodiesel Degradation: Correlation with Acid Value and UV Absorption Analyses.

    Science.gov (United States)

    Vasconcelos, Maydla Dos Santos; Passos, Wilson Espíndola; Lescanos, Caroline Honaiser; Pires de Oliveira, Ivan; Trindade, Magno Aparecido Gonçalves; Caires, Anderson Rodrigues Lima; Muzzi, Rozanna Marques

    2018-01-01

    The techniques used to monitor the quality of the biodiesel are intensely discussed in the literature, partly because of the different oil sources and their intrinsic physicochemical characteristics. This study aimed to monitor the thermal degradation of the fatty acid methyl esters of Sesamum indicum L. and Raphanus sativus L. biodiesels (SILB and RSLB, resp.). The results showed that both biodiesels present a high content of unsaturated fatty acids, ∼84% (SILB) and ∼90% (RSLB). The SILB had a high content of polyunsaturated linoleic fatty acid (18  :  2), about 49%, and the oleic monounsaturated (18  :  1), ∼34%. On the other hand, RSLB presented a considerable content of linolenic fatty acid (18  :  3), ∼11%. The biodiesel samples were thermal degraded at 110°C for 48 hours, and acid value, UV absorption, and fluorescence spectroscopy analysis were carried out. The results revealed that both absorption and fluorescence presented a correlation with acid value as a function of degradation time by monitoring absorptions at 232 and 270 nm as well as the emission at 424 nm. Although the obtained correlation is not completely linear, a direct correlation was observed in both cases, revealing that both properties can be potentially used for monitoring the biodiesel degradation.

  12. Use of COD, TOC, and Fluorescence Spectroscopy to Estimate BOD in Wastewater.

    Science.gov (United States)

    Christian, Evelyn; Batista, Jacimaria R; Gerrity, Daniel

    2017-02-01

      Common to all National Pollutant Discharge Elimination System (NPDES) permits in the United States is a limit on biochemical oxygen demand (BOD). Chemical oxygen demand (COD), total organic carbon (TOC), and fluorescence spectroscopy are also capable of quantifying organic content, although the mechanisms of quantification and the organic fractions targeted differ for each test. This study explores correlations between BOD5 and these alternate test procedures using facility influent, primary effluent, and facility effluent samples from a full-scale water resource recovery facility. Relative reductions of the water quality parameters proved to be strong indicators of their suitability as surrogates for BOD5. Suitable correlations were generally limited to the combined datasets for the three sampling locations or the facility effluent alone. COD exhibited relatively strong linear correlations with BOD5 when considering the three sample points (r = 0.985) and the facility effluent alone (r = 0.914), while TOC exhibited a suitable linear correlation with BOD5 in the facility effluent (r = 0.902). Exponential regressions proved to be useful for estimating BOD5 based on TOC or fluorescence (r > 0.95).

  13. Detection and characterization of stomach cancer and atrophic gastritis with fluorescence and Raman spectroscopy

    Science.gov (United States)

    Li, Xiaozhou; Lin, Junxiu; Jia, Chunde; Wang, Rong

    2003-12-01

    In this paper, we attempt to find a valid method to distinguish gastric cancer and atrophic gastritis. Auto-fluorescence and Raman spectroscopy of laser induced (514.5 nm and 488.0 nm) was measured. The serum spectrum is different between normal and cancer. Average value of diagnosis parameter for normal serum, red shift is less than 12 nm and Raman relative intensity of peak C by 514.5 nm excited is stronger than that of 488.0 nm. To gastric cancer, its red shift of average is bigger than 12 nm and relative intensity of Raman peak C by 514.5 nm excited is weaker than that by 488.0 nm. To atrophic gastritis, the distribution state of Raman peaks is similar with normal serum and auto-fluorescence spectrum's shape is similar to that of gastric cancer. Its average Raman peak red shift is bigger than 12 nm and the relative intensity of peak C by 514.5 excited is stronger than that of by 488.0. We considered it as a criterion and got an accuracy of 85.6% for diagnosis of gastric cancer compared with the result of clinical diagnosis.

  14. Short communication: Suitability of fluorescence spectroscopy for characterization of commercial milk of different composition and origin.

    Science.gov (United States)

    Ntakatsane, M P; Yang, X Q; Lin, M; Liu, X M; Zhou, P

    2011-11-01

    Thirteen milk brands comprising 76 pasteurized and UHT milk samples of various compositions (whole, reduced fat, skimmed, low lactose, and high protein) were obtained from local supermarkets, and milk samples manufactured in various countries were discriminated using front-face fluorescence spectroscopy (FFFS) coupled with chemometric tools. The emission spectra of Maillard reaction products and riboflavin (MRP/RF; 400 to 600 nm) and tryptophan (300 to 400 nm) were recorded using FFFS, and the excitation wavelengths were set at 360 nm for MRP/RF and 290 nm for tryptophan. Principal component analysis (PCA) was applied to analyze the normalized spectra. The PCA of spectral information from MRP/RF discriminated the milk samples originating in different countries, and PCA of spectral information from tryptophan discriminated the samples according to composition. The fluorescence spectral data were compared with liquid chromatography-mass spectrometry results for the glycation extent of the milk samples, and a positive association (R(2)=0.84) was found between the degree of glycation of α-lactalbumin and the MRP/RF spectral data. This study demonstrates the ability and sensitivity of FFFS to rapidly discriminate and classify commercial milk with various compositions and processing conditions. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Characterization of protein adsorption onto FePt nanoparticles using dual-focus fluorescence correlation spectroscopy

    Directory of Open Access Journals (Sweden)

    Pauline Maffre

    2011-07-01

    Full Text Available Using dual-focus fluorescence correlation spectroscopy, we have analyzed the adsorption of three human blood serum proteins, namely serum albumin, apolipoprotein A-I and apolipoprotein E4, onto polymer-coated, fluorescently labeled FePt nanoparticles (~12 nm diameter carrying negatively charged carboxyl groups on their surface. For all three proteins, a step-wise increase in hydrodynamic radius with protein concentration was observed, strongly suggesting the formation of protein monolayers that enclose the nanoparticles. Consistent with this interpretation, the absolute increase in hydrodynamic radius can be correlated with the molecular shapes of the proteins known from X-ray crystallography and solution experiments, indicating that the proteins bind on the nanoparticles in specific orientations. The equilibrium dissociation coefficients, measuring the affinity of the proteins to the nanoparticles, were observed to differ by almost four orders of magnitude. These variations can be understood in terms of the electrostatic properties of the proteins. From structure-based calculations of the surface potentials, positively charged patches of different extents can be revealed, through which the proteins interact electrostatically with the negatively charged nanoparticle surfaces.

  16. Investigating temperature effects on extra virgin olive oil using fluorescence spectroscopy

    Science.gov (United States)

    Saleem, M.; Ahmad, Naveed; Ali, H.; Bilal, M.; Khan, Saranjam; Ullah, Rahat; Ahmed, M.; Mahmood, S.

    2017-12-01

    The potential of fluorescence spectroscopy has been utilized to study the heating effects on extra virgin olive oil (EVOO). Through a series of experiments, a temperature range from 140 °C  -  150 °C has been found where cooking with EVOO is possible without destroying its natural ingredients. Fluorescence emission spectra from all heated and non-heated EVOO samples were recorded using an excitation source at 350 nm, where emission bands in non-heated EVOO at 380, 440, 455, and 525 nm are labelled for vitamin E and a band at 673 nm is assigned for chlorophyll a. The emission band at 525 nm is also responsible for beta carotenoids (vitamin A). As a result of heating, prominent intensity variations have been observed in all spectral bands, but it is particularly affected at 525 nm, indicating the deterioration of vitamin E and beta carotenoids. However, if the temperature of oil can be maintained in the above defined range, then frying food with EVOO is possible by preserving its natural ingredients. The spectral variations resulting from the heating effects have been further highlighted by using principal component analysis for classification purposes.

  17. Light adaptation of the unicellular red alga, Cyanidioschyzon merolae, probed by time-resolved fluorescence spectroscopy.

    Science.gov (United States)

    Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

    2015-08-01

    Photosynthetic organisms change the quantity and/or quality of their pigment-protein complexes and the interactions among these complexes in response to light conditions. In the present study, we analyzed light adaptation of the unicellular red alga Cyanidioschyzon merolae, whose pigment composition is similar to that of cyanobacteria because its phycobilisomes (PBS) lack phycoerythrin. C. merolae were grown under different light qualities, and their responses were measured by steady-state absorption, steady-state fluorescence, and picosecond time-resolved fluorescence spectroscopies. Cells were cultivated under four monochromatic light-emitting diodes (blue, green, yellow, and red), and changes in pigment composition and energy transfer were observed. Cells grown under blue and green light increased their relative phycocyanin levels compared with cells cultured under white light. Energy-transfer processes to photosystem I (PSI) were sensitive to yellow and red light. The contribution of direct energy transfer from PBS to PSI increased only under yellow light, while red light induced a reduction in energy transfer from photosystem II to PSI and an increase in energy transfer from light-harvesting chlorophyll protein complex I to PSI. Differences in pigment composition, growth, and energy transfer under different light qualities are discussed.

  18. Fluorescence Spectroscopy Applied to Monitoring Biodiesel Degradation: Correlation with Acid Value and UV Absorption Analyses

    Directory of Open Access Journals (Sweden)

    Maydla dos Santos Vasconcelos

    2018-01-01

    Full Text Available The techniques used to monitor the quality of the biodiesel are intensely discussed in the literature, partly because of the different oil sources and their intrinsic physicochemical characteristics. This study aimed to monitor the thermal degradation of the fatty acid methyl esters of Sesamum indicum L. and Raphanus sativus L. biodiesels (SILB and RSLB, resp.. The results showed that both biodiesels present a high content of unsaturated fatty acids, ∼84% (SILB and ∼90% (RSLB. The SILB had a high content of polyunsaturated linoleic fatty acid (18  :  2, about 49%, and the oleic monounsaturated (18  :  1, ∼34%. On the other hand, RSLB presented a considerable content of linolenic fatty acid (18  :  3, ∼11%. The biodiesel samples were thermal degraded at 110°C for 48 hours, and acid value, UV absorption, and fluorescence spectroscopy analysis were carried out. The results revealed that both absorption and fluorescence presented a correlation with acid value as a function of degradation time by monitoring absorptions at 232 and 270 nm as well as the emission at 424 nm. Although the obtained correlation is not completely linear, a direct correlation was observed in both cases, revealing that both properties can be potentially used for monitoring the biodiesel degradation.

  19. Fluorescence correlation spectroscopy to study antibody binding and stoichiometry of complexes

    Science.gov (United States)

    Swift, Kerry M.; Matayoshi, Edmund D.

    2008-02-01

    FCS (fluorescence correlation spectroscopy) was used to study the association at the single molecule level of tumor necrosis factor alpha (TNF-α) and two of its protein antagonists Humira (TM) (adalimumab), a fully humanized monoclonal antibody, and Enbrel (TM) (etanercept), a soluble form of the TNF receptor. Single molecule approaches potentially have the advantage not only of enhanced sensitivity, but also of observing at equilibrium the details that would otherwise be lost in classical ensemble experiments where heterogeneity is averaged. We prepared fluorescent conjugates of the protein drugs and their biological target, the trimeric soluble form of TNF-α. The bivalency of adalimumab and the trimeric nature of TNF-α potentially allow several forms of associative complexes that may differ in stoichiometry. Detailed knowledge of this reaction may be relevant to understanding adalimumab's pharmacological properties. Our FCS data showed that a single trimeric TNF-α can bind up to three adalimumab molecules. Under some conditions even larger complexes are formed, apparently the result of cross-linking of TNF-α trimers by adalimumab. In addition, distinct differences between Humira and Enbrel were observed in their association with TNF-α.

  20. Effect of Exogenous Phytase Addition on Soil Phosphatase Activities: a Fluorescence Spectroscopy Study.

    Science.gov (United States)

    Yang, Xiao-zhu; Chen, Zhen-hua; Zhang, Yu-lan; Chen, Li-jun

    2015-05-01

    The utilization of organic phosphorus (P) has directly or indirectly improved after exogenous phytase was added to soil. However, the mechanism by which exogenous phytase affected the soil phosphatases (phosphomonoesterase and phosphodiesterase) activities was not clear. The present work was aimed to study red soil, brown soil and cinnamon soil phosphomonoesterase (acid and alkaline) (AcP and AlP) and phosphodiesterase (PD) activities responding to the addition of exogenous phytase (1 g phytase/50 g air dry soil sample) based on the measurements performed via a fluorescence detection method combined with 96 microplates using a TECAN Infinite 200 Multi-Mode Microplate Reader. The results indicated that the acid phosphomonoesterase activity was significantly enhanced in red soil (p≤0. 01), while it was significantly reduced in cinnamon soil; alkaline phosphomonoesterase activity was significantly enhanced in cinnamon soil (p≤ 0. 01), while it was significantly reduced in red soil; phosphodiesterase activity was increased in three soils but it was significantly increased in brown soil (p≤0. 01) after the addition of exogenous phytase. The activities still remained strong after eight days in different soils, which indicated that exogenous phytase addition could be enhance soil phosphatases activities effectively. This effect was not only related to soil properties, such as pH and phosphorus forms, but might also be related to the excreted enzyme amount of the stimulating microorganism. Using fluorescence spectroscopy to study exogenous phytase addition influence on soil phosphatase activities was the first time at home and abroad. Compared with the conventional spectrophotometric method, the fluorescence microplate method is an accurate, fast and simple to use method to determine the relationships among the soil phosphatases activities.

  1. High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

    International Nuclear Information System (INIS)

    Wang, Xin

    1996-12-01

    X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of Kα and Kβ emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS

  2. In vivo imaging of membrane type-1 matrix metalloproteinase with a novel activatable near-infrared fluorescence probe.

    Science.gov (United States)

    Shimizu, Yoichi; Temma, Takashi; Hara, Isao; Makino, Akira; Kondo, Naoya; Ozeki, Ei-Ichi; Ono, Masahiro; Saji, Hideo

    2014-08-01

    Membrane type-1 matrix metalloproteinase (MT1-MMP) is a protease activating MMP-2 that mediates cleavage of extracellular matrix components and plays pivotal roles in tumor migration, invasion and metastasis. Because in vivo noninvasive imaging of MT1-MMP would be useful for tumor diagnosis, we developed a novel near-infrared (NIR) fluorescence probe that can be activated following interaction with MT1-MMP in vivo. MT1-hIC7L is an activatable fluorescence probe comprised of anti-MT1-MMP monoclonal antibodies conjugated to self-assembling polymer micelles that encapsulate NIR dyes (IC7-1, λem : 858 nm) at concentrations sufficient to cause fluorescence self-quenching. In aqueous buffer, MT1-hIC7L fluorescence was suppressed to background levels and increased approximately 35.5-fold in the presence of detergent. Cellular uptake experiments revealed that in MT1-MMP positive C6 glioma cells, MT1-hIC7L showed significantly higher fluorescence that increased with time as compared to hIC7L, a negative control probe lacking the anti-MT1-MMP monoclonal antibody. In MT1-MMP negative MCF-7 breast adenocarcinoma cells, both MT1-hIC7L and hIC7L showed no obvious fluorescence. In addition, the fluorescence intensity of C6 cells treated with MT1-hIC7L was suppressed by pre-treatment with an MT1-MMP endocytosis inhibitor (P imaging using probes intravenously administered to tumor-bearing mice showed that MT1-hIC7L specifically visualized C6 tumors (tumor-to-background ratios: 3.8 ± 0.3 [MT1-hIC7L] vs 3.1 ± 0.2 [hIC7L] 48 h after administration, P fluorescence in MCF-7 tumors. Together, these results show that MT1-hIC7L would be a potential activatable NIR probe for specifically detecting MT1-MMP-expressing tumors. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  3. X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy analysis of Roman silver denarii

    Energy Technology Data Exchange (ETDEWEB)

    Pardini, L. [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); El Hassan, A. [National Institute for Laser- Enhanced Sciences (NILES), Cairo University Giza (Egypt); Ferretti, M. [Istituto per le Tecnologie Applicate ai Beni Culturali, Area della Ricerca del CNR di Montelibretti Roma (Italy); Foresta, A.; Legnaioli, S.; Lorenzetti, G. [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Nebbia, E. [Universita degli Studi di Torino (Italy); Catalli, F. [Monetiere di Firenze, Museo Archeologico Nazionale Firenze (Italy); Harith, M.A. [National Institute for Laser- Enhanced Sciences (NILES), Cairo University Giza (Egypt); Diaz Pace, D. [Institute of Physics ' Arroyo Seco' , Faculty of Science, Tandil (Argentina); Anabitarte Garcia, F. [Photonics Engineering Group, University of Cantabria, Santander (Spain); Scuotto, M. [Dipartimento di Scienze Archeologiche, Via Galvani 1, 56126 Pisa (Italy); Palleschi, V., E-mail: vincenzo.palleschi@cnr.it [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Dipartimento di Scienze Archeologiche, Via Galvani 1, 56126 Pisa (Italy)

    2012-08-15

    In this paper we present the results of a study performed on a large collection of silver Roman republican denarii, encompassing about two centuries of history. The joint use of Laser-Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF) spectroscopy allowed for an accurate determination of the coins' elemental composition; the measurements, performed mostly in situ at the 'Monetiere' in Florence, revealed a striking connection between the 'quality' of the silver alloy and some crucial contemporary events. This finding was used to classify a group of denarii whose dating was otherwise impossible. The comparison with other contemporary denarii disproves a recent theory on the origin of the so called 'serrated' denarii (denarii showing notched chisel marks on the edge of the coin). - Highlights: Black-Right-Pointing-Pointer We studied a large collection of Roman republican silver denarii. Black-Right-Pointing-Pointer XRF and LIBS allowed to determine the precious metal content of the coins. Black-Right-Pointing-Pointer A correlation of the 'quality' of the alloy with some contemporary events was found. Black-Right-Pointing-Pointer The study allowed to controvert a recent theory on the so called 'serrated' denarii.

  4. X-ray Fluorescence Spectroscopy of Pre-Federal American Currency

    Science.gov (United States)

    Raddell, Mark; Manukyan, Khachatur; Aprahamian, Ani; Wiescher, Michael; Jordan, Louis

    2017-09-01

    X-ray Fluorescence Spectroscopy (XRF) was used to study 17th and 18th century Mexican, Potosí, and Massachusetts silver colonial coins from the University of Notre Dame's Rare Books and Special Collections. Using different configurations and devices, we have learned more about the limitations and optimizations of the method. We have developed a moveable stand that may be used for XRF mapping of coin surfaces. We created standard silver alloy materials for quantification of the elemental composition of the coins. Inductively coupled plasma (ICP) spectroscopy was applied to determine the precise composition of the standards for accurate and non-destructive analyses of the colonial coins. XRF measurements were performed using two different XRF spectrometers, in both air and vacuum conditions, as well as an x-ray beam tube of varying diameters from 2 mm, 1 mm, and 0.03 mm. We quantified both the major elements and the bulk and surface impurities for 90 coins. We are using PCA to look at possible correlations between compositions of coinage from different geographical regions. Preliminary data analyses suggest that Massachusetts coins were minted using silver from Latin American sources. These results are of great interest to historians in tracing the origins of the currency. This work was made possible by the Notre Dame College of Science Summer Undergraduate Research Fellowships (COS-SURF).

  5. Estimation of AOT and SDS CMC in a methanol using conductometry, viscometry and pyrene fluorescence spectroscopy methods

    Science.gov (United States)

    Mitsionis, Anastasios I.; Vaimakis, Tiverios C.

    2012-09-01

    Critical micelle concentration (CMC) of two anionic surfactants in methanol was estimated using conductometry, viscometry and pyrene fluorescence spectroscopy methods. The surfactants used, were sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol-OT, AOT) and sodium dodecyl sulfate (SDS) dispersed in pure methanol. The CMC determination was evaluated in room temperature. The results have shown nearly similar concentrations.

  6. Usage of ray tracing transfer matrix to mitigate the stray light for ITER spectroscopy

    International Nuclear Information System (INIS)

    Kajita, S.; Veshchev, E.; Barnsley, R.; Walsh, M.

    2016-01-01

    Stray light formed by the reflection of photons on inner wall from a bright divertor region can be a serious issue in spectroscopic measurement systems in ITER. In this study, we propose a method to mitigate the influence of stray light using a ray tracing analysis. Usually, a ray tracing simulation requires a time consuming runs. We constructed transfer matrices based on the ray tracing simulation results and used them to demonstrate the influence of stray light. It is shown that the transfer matrix can be used to reconstruct the emission profile by considering the influence of the stray light without any additional ray tracing runs. Mitigation of the stray light in ITER divertor impurity monitor was demonstrated, and a method of prediction of the stray light level for the scrape off layer spectroscopy from divertor region was proposed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Energy dispersive X-ray fluorescence determination of cadmium in uranium matrix using Cd Kα line excited by continuum

    International Nuclear Information System (INIS)

    Dhara, Sangita; Misra, N.L.; Aggarwal, S.K.; Venugopal, V.

    2010-01-01

    An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90 μg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700 μg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5 mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd Kα intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1σ) and the results deviated from the expected values by < 4% on average.

  8. Time-resolved spectroscopy of the probe fluorescence in the study of human blood protein dynamic structure on SR beam

    International Nuclear Information System (INIS)

    Dobretsov, G.E.; Kurek, N.K.; Syrejshchikova, T.I.; Yakimenko, M.N.; Clarke, D.T.; Jones, G.R.; Munro, I.H.

    2000-01-01

    Time-resolved spectroscopy on the SRS of the Daresbury Laboratory was used for the study of the human serum lipoproteins and human blood albumins with fluorescent probes K-37 and K-35, developed in Russia. The probe K-37 was found sensitive to the difference in dynamic properties of the lipid objects. Two sets of the parameters were used for the description of lipid dynamic structure: (1) time-resolved fluorescence spectra and (2) time-resolved fluorescence depolarization as a function of rotational mobility of lipid molecules. Each measured dynamic parameter reflected the monotonous changes of dynamic properties in the range: lipid spheres-very low density lipoproteins-low density lipoproteins-high density lipoproteins-phospholipid liposomes. The range is characterized by the increase of the ratio polar/ nonpolar lipids. Thus, time-resolved fluorescence could be used to detect some structural modifications in lipoproteins related to atherosclerosis and subsequent cardiovascular diseases development

  9. Front-face fluorescence spectroscopy study of globular proteins in emulsions: displacement of BSA by a nonionic surfactant.

    Science.gov (United States)

    Rampon, V; Genot, C; Riaublanc, A; Anton, M; Axelos, M A V; McClements, D J

    2003-04-23

    The displacement of a globular protein (bovine serum albumin, BSA) from the surface of oil droplets in concentrated oil-in-water emulsions by a nonionic surfactant (polyoxyethylene sorbitan monolauarate, Tween 20) was studied using front-face fluorescence spectroscopy (FFFS). This method relies on measurement of the change in intensity (I(MAX)) and wavelength (lambda(MAX)) of the maximum in the tryptophan emission spectrum. A series of oil-in-water emulsions (21 wt % n-hexadecane, 0.22 wt % BSA, pH 7.0) containing different molar ratios of Tween 20 to BSA (R = 0-131) were prepared. As the surfactant concentration was increased, the protein was progressively displaced from the droplet surfaces. At R > or = 66, the protein was completely displaced from the droplet surfaces. There was an increase in both I(MAX) and lambda(MAX) with increasing Tween 20 concentration up to R = 66, which correlated with the increase in the ratio of nonadsorbed to adsorbed protein. In contrast, there was a decrease in I(MAX) and lambda(MAX) with Tween 20 concentration in protein solutions and for R > or = 66 in the emulsions, which was attributed to binding of the surfactant to the protein. This study shows that FFFS is a powerful technique for nondestructively providing information about the interfacial composition of droplets in concentrated protein-stabilized emulsions in situ. Nevertheless, in general the suitability of the technique may also depend on protein type and the nature of the physicochemical matrix surrounding the proteins.

  10. Fluorescence correlation spectroscopy analysis for accurate determination of proportion of doubly labeled DNA in fluorescent DNA pool for quantitative biochemical assays.

    Science.gov (United States)

    Hou, Sen; Sun, Lili; Wieczorek, Stefan A; Kalwarczyk, Tomasz; Kaminski, Tomasz S; Holyst, Robert

    2014-01-15

    Fluorescent double-stranded DNA (dsDNA) molecules labeled at both ends are commonly produced by annealing of complementary single-stranded DNA (ssDNA) molecules, labeled with fluorescent dyes at the same (3' or 5') end. Because the labeling efficiency of ssDNA is smaller than 100%, the resulting dsDNA have two, one or are without a dye. Existing methods are insufficient to measure the percentage of the doubly-labeled dsDNA component in the fluorescent DNA sample and it is even difficult to distinguish the doubly-labeled DNA component from the singly-labeled component. Accurate measurement of the percentage of such doubly labeled dsDNA component is a critical prerequisite for quantitative biochemical measurements, which has puzzled scientists for decades. We established a fluorescence correlation spectroscopy (FCS) system to measure the percentage of doubly labeled dsDNA (PDL) in the total fluorescent dsDNA pool. The method is based on comparative analysis of the given sample and a reference dsDNA sample prepared by adding certain amount of unlabeled ssDNA into the original ssDNA solution. From FCS autocorrelation functions, we obtain the number of fluorescent dsDNA molecules in the focal volume of the confocal microscope and PDL. We also calculate the labeling efficiency of ssDNA. The method requires minimal amount of material. The samples have the concentration of DNA in the nano-molar/L range and the volume of tens of microliters. We verify our method by using restriction enzyme Hind III to cleave the fluorescent dsDNA. The kinetics of the reaction depends strongly on PDL, a critical parameter for quantitative biochemical measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Analysis of nutrition-relevant trace elements in human blood and serum by means of total reflection X-ray fluorescence (TXRF) spectroscopy

    International Nuclear Information System (INIS)

    Stosnach, Hagen; Mages, Margarete

    2009-01-01

    In clinical service laboratories, one of the most common analytical tasks with regard to inorganic traces is the determination of the nutrition-relevant elements Fe, Cu, Zn, and Se. Because of the high numbers of samples and the commercial character of these analyses, a time-consuming sample preparation must be avoided. In this presentation, the results of total reflection X-ray fluorescence measurements with a low-power system and different sample preparation procedures are compared with those derived from analysis with common methods like Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The results of these investigations indicate that the optimal total reflection X-ray fluorescence analysis of the nutrition-relevant elements Fe, Cu, Zn, and Se can be performed by preparing whole blood and serum samples after dilution with ultrapure water and transferring 10 μl of internally standardized sample to an unsiliconized quartz glass sample carrier with subsequent drying in a laboratory oven. Suitable measurement time was found to be 600 s. The enhanced sample preparation by means of microwave or open digestion, in parts combined with cold plasma ashing, led to an improvement of detection limits by a factor of 2 for serum samples while for whole blood samples an improvement was only observed for samples prepared by means of microwave digestion. As the matrix elements P, S, Cl, and for whole blood Fe have a major influence on the detection limits, most probably a further enhancement of analytical quality requires the removal of the organic matrix. However, for the routine analysis of the nutrition-relevant elements, the dilution preparation was found to be sufficient.

  12. Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

    International Nuclear Information System (INIS)

    Miyabe, M.; Oba, M.; Iimura, H.; Akaoka, K.; Khumaeni, A.; Kato, M.; Wakaida, I.

    2015-01-01

    The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5–6 J/cm 2 ) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis. - Highlights: • Ablated ground-state species accumulated in a thin hemispherical boundary layer • Inside the layer, a cavity containing a small density of ablated species was formed. • The hemispherical layers of atoms and ions appeared at a nearly identical location. • The measured intensity peak variation was in good agreement with a model prediction. • We ascribed the dominant process for forming the layer to a three-body recombination

  13. Using fluorescence correlation spectroscopy to study conformational changes in denatured proteins.

    Science.gov (United States)

    Sherman, Eilon; Itkin, Anna; Kuttner, Yosef Yehuda; Rhoades, Elizabeth; Amir, Dan; Haas, Elisha; Haran, Gilad

    2008-06-01

    Fluorescence correlation spectroscopy (FCS) is a sensitive analytical tool that allows dynamics and hydrodynamics of biomolecules to be studied under a broad range of experimental conditions. One application of FCS of current interest is the determination of the size of protein molecules in the various states they sample along their folding reaction coordinate, which can be accessed through the measurement of diffusion coefficients. It has been pointed out that the analysis of FCS curves is prone to artifacts that may lead to erroneous size determination. To set the stage for FCS studies of unfolded proteins, we first show that the diffusion coefficients of small molecules as well as proteins can be determined accurately even in the presence of high concentrations of co-solutes that change the solution refractive index significantly. Indeed, it is found that the Stokes-Einstein relation between the measured diffusion coefficient and solution viscosity holds even in highly concentrated glycerol or guanidinium hydrochloride (GuHCl) solutions. These measurements form the basis for an investigation of the structure of the denatured state of two proteins, the small protein L and the larger, three-domain protein adenylate kinase (AK). FCS is found useful for probing expansion in the denatured state beyond the unfolding transition. It is shown that the denatured state of protein L expands as the denaturant concentration increases, in a process akin to the transition from a globule to a coil in polymers. This process continues at least up to 5 M GuHCl. On the other hand, the denatured state of AK does not seem to expand much beyond 2 M GuHCl, a result that is in qualitative accord with single-molecule fluorescence histograms. Because both the unfolding transition and the coil-globule transition of AK occur at a much lower denaturant concentration than those of protein L, a possible correlation between the two phenomena is suggested.

  14. Automatic classification of fluorescence and optical diffusion spectroscopy data in neuro-oncology

    Science.gov (United States)

    Savelieva, T. A.; Loshchenov, V. B.; Goryajnov, S. A.; Potapov, A. A.

    2018-04-01

    The complexity of the biological tissue spectroscopic analysis due to the overlap of biological molecules' absorption spectra, multiple scattering effect, as well as measurement geometry in vivo has caused the relevance of this work. In the neurooncology the problem of tumor boundaries delineation is especially acute and requires the development of new methods of intraoperative diagnosis. Methods of optical spectroscopy allow detecting various diagnostically significant parameters non-invasively. 5-ALA induced protoporphyrin IX is frequently used as fluorescent tumor marker in neurooncology. At the same time analysis of the concentration and the oxygenation level of haemoglobin and significant changes of light scattering in tumor tissues have a high diagnostic value. This paper presents an original method for the simultaneous registration of backward diffuse reflectance and fluorescence spectra, which allows defining all the parameters listed above simultaneously. The clinical studies involving 47 patients with intracranial glial tumors of II-IV Grades were carried out in N.N. Burdenko National Medical Research Center of Neurosurgery. To register the spectral dependences the spectroscopic system LESA- 01-BIOSPEC was used with specially developed w-shaped diagnostic fiber optic probe. The original algorithm of combined spectroscopic signal processing was developed. We have created a software and hardware, which allowed (as compared with the methods currently used in neurosurgical practice) to increase the sensitivity of intraoperative demarcation of intracranial tumors from 78% to 96%, specificity of 60% to 82%. The result of analysis of different techniques of automatic classification shows that in our case the most appropriate is the k Nearest Neighbors algorithm with cubic metrics.

  15. Matrix isolation FT-IR spectroscopy and molecular orbital study of sarcosine methyl ester

    Science.gov (United States)

    Gómez-Zavaglia, A.; Fausto, R.

    2004-02-01

    N-methylglycine methyl ester (sarcosine-Me) has been studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d,p) and 6-31++G(d,p) basis set, respectively. Twelve different conformers were located in the potential energy surface of the studied compound, with the ASC conformer being the ground conformational state. This form is analogous to the dimethylglycine methyl ester most stable conformer and is characterized by a NH⋯O intramolecular hydrogen bond; in this form, the ester group assumes the cis configuration and the OC-C-N and Lp-N-C-C (where Lp is the nitrogen lone electron pair) dihedral angles are ca. -17.8 and 171.3°, respectively. The second most stable conformer ( GSC) differs from the ASC conformer essentially in the conformation assumed by the methylamino group, which in this case is gauche ( Lp-N-C-C dihedral angle equal to 79.4°). On the other hand, the third most stable conformer ( AAC) differs from the most stable form in the conformation of the OC-C-N axis (151.4°). These three forms were predicted to differ in energy by less than ca. 5 kJ mol -1 and represent ≈95% of the total conformational population at room temperature. FT-IR spectra were obtained for sarcosine-Me isolated in argon matrices (T=9 K) revealing the presence in the matrices of the three lowest energy conformers predicted by the calculations. The matrices were prepared by deposition of the vapour of the compound using two different nozzle temperatures, 25 and 60 °C. The relative populations of the three conformers trapped in the matrices were found to be consistent with occurrence of conformational cooling during matrix deposition and with a stabilization of the most polar GSC and AAC conformers in the matrices compared to the gas phase. Indeed, like it was previously observed for the methyl ester of dimethylglycine [Phys. Chem. Chem. Phys. 5 (2003) 52] the different

  16. Optical absorption and fluorescence spectroscopy studies of Artepillin C, the major component of green propolis

    Science.gov (United States)

    Camuri, Isamara Julia; Costa, Adriano Batista; Ito, Amando Siuiti; Pazin, Wallance Moreira

    2018-06-01

    The bioactivity of propolis against several pathogens is well established, leading to the extensive consumption of that bee product to prevent diseases. Brazilian green propolis, collected by the species Apis mellifera, is one of the most consumed in the world. The chemical composition of green propolis is complex and it has been shown that it displays antioxidant, antimicrobial, anti-inflammatory and antitumor activities, especially due to the high content of Artepillin C. The molecule is a derivative of cinnamic acid with two prenylated groups, responsible for the improvement of the affinity of the compound for lipophilic environment. A carboxylic group (COOH) is also present in the molecule, making it a pH-sensitive compound and the pH-dependent structure of Artepillin C, may modulate its biological activity related to interactions with the cellular membrane of organisms and tissues. Molecular properties of Artepillin C on aqueous solution were examined by optical absorption, steady state and time-resolved fluorescence spectroscopies. Acid-base titration based on the spectral position of the near UV absorption band, resulted in the pKa value of 4.65 for the carboxylic group in Artepillin C. In acidic pH, below the pKa value, an absorption band raised around 350 nm at Artepillin C concentration above 50 μM, due to aggregation of the molecule. In neutral pH, with excitation at 310 nm, Artepillin C presents dual emission at 400 and 450 nm. In pH close to the pKa, the optical spectra show contribution from both protonated and deprotonated species. A three-exponential function was necessary to fit the intensity decays at the different pHs, dominated by a very short lifetime component, around 0.060 ns. The fast decay resulted in emission before fluorescence depolarization, and in values of fluorescence anisotropy higher than could be expected for monomeric forms of the compound. The results give fundamental knowledge about the protonation-deprotonation state of the

  17. Laser-induced Fluorescence Spectroscopy for applications in chemical sensing and optical refrigeration

    Science.gov (United States)

    Kumi Barimah, Eric

    Laser-induced breakdown spectroscopy (LIBS) is an innovative technique that has been used as a method for fast elemental analysis in real time. Conventional ultraviolet-visible (UV-VIS) LIBS has been applied to detect the elemental composition of different materials, including explosives, pharmaceutical drugs, and biological samples. The extension of conventional LIBS to the infrared region (˜1-12 mum) promises to provide additional information on molecular emission signatures due to rotational-vibrational transitions. In this research, a pulsed Nd: YAG laser operating at 1064 nm was focused onto several sodium compounds (NaCl, NaClO3, Na2CO3 and NaClO4) and potassium compounds (KCl, KClO3, K2CO3 and KClO4) to produce an intense plasma at the target surface. Several distinct infrared (IR) atomic emission signatures were observed from all sodium and potassium containing compounds. The atomic emission lines observed from the investigated samples matched assigned transitions of neutral sodium and potassium atoms published in the National Institute of Standards and Technology (NIST) atomic database. In addition to the intense atomic lines, the rst evidence of molecular LIBS emission structures were observed at ˜10.0 m in KClO3 and NaClO3 for the chlorate anion (ClO3 --1), at ˜6.7 to 8.0 mum in KNO3 and NaNO 3 for the nitrate anion (NO3--1 ), ˜8.0 to 10.0 mum in KClO4 and NaClO4 for perchlorate anion (ClO4--1 ), and ˜6.88 mum and 11.53 mum in Na2CO3 for the carbonate anion (CO3--1 ). The observed molecular emission showed strong correlation with the conventional Fourier Transform Infrared Spectrometry (FTIR) absorption spectra of the investigated samples. IR LIBS was also applied to determine the limit of detection (LOD) for the perchlorate anion in KClO4 using the 8.0 -11.0 mum IR-LIBS emission band. The calibration curve of ClO4 in KClO4 was constructed using peak and integrated emission intensities for known concentrations of mixed KClO4/NH4NO3 samples. The

  18. Characterization of CDOM of river waters in China using fluorescence excitation-emission matrix and regional integration techniques

    Science.gov (United States)

    Zhao, Ying; Song, Kaishan; Shang, Yingxin; Shao, Tiantian; Wen, Zhidan; Lv, Lili

    2017-08-01

    The spatial characteristics of fluorescent dissolved organic matter (FDOM) components in river waters in China were first examined by excitation-emission matrix spectra and fluorescence regional integration (FRI) with the data collected during September to November between 2013 and 2015. One tyrosine-like (R1), one tryptophan-like (R2), one fulvic-like (R3), one microbial protein-like (R4), and one humic-like (R5) components have been identified by FRI method. Principal component analysis (PCA) was conducted to assess variations in the five FDOM components (FRί (ί = 1, 2, 3, 4, and 5)) and the humification index for all 194 river water samples. The average fluorescence intensities of the five fluorescent components and the total fluorescence intensities FSUM differed under spatial variation among the seven major river basins (Songhua, Liao, Hai, Yellow and Huai, Yangtze, Pearl, and Inflow Rivers) in China. When all the river water samples were pooled together, the fulvic-like FR3 and the humic-like FR5 showed a strong positive linear relationship (R2 = 0.90, n = 194), indicating that the two allochthonous FDOM components R3 and R5 may originate from similar sources. There is a moderate strong positive correlation between the tryptophan-like FR2 and the microbial protein-like FR4 (R2 = 0.71, n = 194), suggesting that parts of two autochthonous FDOM components R2 and R4 are likely from some common sources. However, the total allochthonous substance FR(3+5) and the total autochthonous substances FR(1+2+4) exhibited a weak correlation (R2 = 0.40, n = 194). Significant positive linear relationships between FR3 (R2 = 0.69, n = 194), FR5 (R2 = 0.79, n = 194), and chromophoric DOM (CDOM) absorption coefficient a(254) were observed, which demonstrated that the CDOM absorption was dominated by the allochthonous FDOM components R3 and R5.

  19. Photolithography and Fluorescence Correlation Spectroscopy used to examine the rates of exchange in reverse micelle systems

    Science.gov (United States)

    Norris, Zach; Mawson, Cara; Johnson, Kyron; Kessler, Sarah; Rebecca, Anne; Wolf, Nathan; Lim, Michael; Nucci, Nathaniel

    Reverse micelles are molecular complexes that encapsulate a nanoscale pool of water in a surfactant shell dissolved in non-polar solvent. These complexes have a wide range of applications, and in all cases, the degree to which reverse micelles (RM) exchange their contents is relevant for their use. Despite its importance, this aspect of RM behavior is poorly understood. Photolithography is employed here to create micro and nano scale fluidic systems in which mixing rates can be precisely measured using fluorescence correlation spectroscopy (FCS). Micro-channel patterns are etched using reactive ion etching process into a layer of silicon dioxide on crystalline silicon substrates. Solutions containing mixtures of reverse micelles, proteins, and fluorophores are placed into reservoirs in the patterns, while diffusion and exchange between RMs is monitored using a FCS system built from a modified confocal Raman spectrometer. Using this approach, the diffusion and exchange rates for RM systems are measured as a function of the components of the RM mixture. Funding provided by Rowan University.

  20. Cell cycle-dependent mobility of Cdc45 determined in vivo by fluorescence correlation spectroscopy.

    Directory of Open Access Journals (Sweden)

    Ronan Broderick

    Full Text Available Eukaryotic DNA replication is a dynamic process requiring the co-operation of specific replication proteins. We measured the mobility of eGFP-Cdc45 by Fluorescence Correlation Spectroscopy (FCS in vivo in asynchronous cells and in cells synchronized at the G1/S transition and during S phase. Our data show that eGFP-Cdc45 mobility is faster in G1/S transition compared to S phase suggesting that Cdc45 is part of larger protein complex formed in S phase. Furthermore, the size of complexes containing Cdc45 was estimated in asynchronous, G1/S and S phase-synchronized cells using gel filtration chromatography; these findings complemented the in vivo FCS data. Analysis of the mobility of eGFP-Cdc45 and the size of complexes containing Cdc45 and eGFP-Cdc45 after UVC-mediated DNA damage revealed no significant changes in diffusion rates and complex sizes using FCS and gel filtration chromatography analyses. This suggests that after UV-damage, Cdc45 is still present in a large multi-protein complex and that its mobility within living cells is consistently similar following UVC-mediated DNA damage.

  1. Mapping vortex-like hydrodynamic flow in microfluidic networks using fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ke Liu; Yu Tian; Burrows, Sean M.; Reif, Randall D. [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States); Pappas, Dimitri, E-mail: d.pappas@ttu.edu [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States)

    2009-09-28

    The ability to quickly measure flow parameters in microfluidic devices is critical for micro total analysis system ({mu}TAS) applications. Macrofluidic methods to assess flow suffer from limitations that have made conventional methods unsuitable for the flow behavior profiling. Single molecule fluorescence correlation spectroscopy (FCS) has been employed in our study to characterize the fluidic vortex generating at a T-shape junction of microscale channels. Due to its high spatial and temporal resolution, the corresponding magnitudes relative to different flow rates in the main channel can be quantitatively differentiated using flow time ({tau}{sub F}) measurements of dye molecules traversing the detection volume in buffer solution. Despite the parabolic flow in the channel upstream, a heterogeneous distribution of flow has been detected across the channel intersection. In addition, our current observations also confirmed the aspect of vortex-shaped flow in low-shear design that was developed previously for cell culture. This approach not only overcomes many technical barriers for examining hydrodynamic vortices and movements in miniature structures without physically integrating any probes, but it is also especially useful for the hydrodynamic studies in polymer-glass based micro -reactor and -mixer.

  2. Tar analysis from biomass gasification by means of online fluorescence spectroscopy

    Science.gov (United States)

    Baumhakl, Christoph; Karellas, Sotirios

    2011-07-01

    Optical methods in gas analysis are very valuable mainly due to their non-intrusive character. That gives the possibility to use them for in-situ or online measurements with only optical intervention in the measurement volume. In processes like the gasification of biomass, it is of high importance to monitor the gas quality in order to use the product gas in proper machines for energy production following the restrictions in the gas composition but also improving its quality, which leads to high efficient systems. One of the main problems in the biomass gasification process is the formation of tars. These higher hydrocarbons can lead to problems in the operation of the energy system. Up to date, the state of the art method used widely for the determination of tars is a standardized offline measurement system, the so-called "Tar Protocol". The aim of this work is to describe an innovative, online, optical method for determining the tar content of the product gas by means of fluorescence spectroscopy. This method uses optical sources and detectors that can be found in the market at low cost and therefore it is very attractive, especially for industrial applications where cost efficiency followed by medium to high precision are of high importance.

  3. Electrohydrodynamic properties of succinoglycan as probed by fluorescence correlation spectroscopy, potentiometric titration and capillary electrophoresis.

    Science.gov (United States)

    Duval, Jérôme F L; Slaveykova, Vera I; Hosse, Monika; Buffle, Jacques; Wilkinson, Kevin J

    2006-10-01

    The electrostatic, hydrodynamic and conformational properties of aqueous solutions of succinoglycan have been analyzed by fluorescence correlation spectroscopy (FCS), proton titration, and capillary electrophoresis (CE) over a large range of pH values and electrolyte (NaCl) concentrations. Using the theoretical formalism developed previously for the electrokinetic properties of soft, permeable particles, a quantitative analysis for the electro-hydrodynamics of succinoglycan is performed by taking into account, in a self-consistent manner, the measured values of the diffusion coefficients, electric charge densities, and electrophoretic mobilities. For that purpose, two limiting conformations for the polysaccharide in solution are tested, i.e. succinoglycan behaves as (i) a spherical, random coil polymer or (ii) a rodlike particle with charged lateral chains. The results show that satisfactory modeling of the titration data for ionic strengths larger than 50 mM can be accomplished using both geometries over the entire range of pH values. Electrophoretic mobilities measured for sufficiently large pH values (pH > 5-6) are in line with predictions based on either model. The best manner to discriminate between these two conceptual models is briefly discussed. For low pH values (pH < 5), both models indicate aggregation, resulting in an increase of the hydrodynamic permeability and a decrease of the diffusion coefficient.

  4. Heat shock-induced interactions among nuclear HSFs detected by fluorescence cross-correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Chan-Gi, E-mail: changipack@amc.seoul.kr [Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Ahn, Sang-Gun [Dept. of Pathology, College of Dentistry, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of)

    2015-07-31

    The cellular response to stress is primarily controlled in cells via transcriptional activation by heat shock factor 1 (HSF1). HSF1 is well-known to form homotrimers for activation upon heat shock and subsequently bind to target DNAs, such as heat-shock elements, by forming stress granules. A previous study demonstrated that nuclear HSF1 and HSF2 molecules in live cells interacted with target DNAs on the stress granules. However, the process underlying the binding interactions of HSF family in cells upon heat shock remains unclear. This study demonstrate for the first time that the interaction kinetics among nuclear HSF1, HSF2, and HSF4 upon heat shock can be detected directly in live cells using dual color fluorescence cross-correlation spectroscopy (FCCS). FCCS analyses indicated that the binding between HSFs was dramatically changed by heat shock. Interestingly, the recovery kinetics of interaction between HSF1 molecules after heat shock could be represented by changes in the relative interaction amplitude and mobility. - Highlights: • The binding interactions among nuclear HSFs were successfully detected. • The binding kinetics between HSF1s during recovery was quantified. • HSF2 and HSF4 strongly formed hetero-complex, even before heat shock. • Nuclear HSF2 and HSF4 bound to HSF1 only after heat shock.

  5. Exchange-dynamics of a neutral hydrophobic dye in micellar solutions studied by Fluorescence Correlation Spectroscopy.

    Science.gov (United States)

    Bordello, Jorge; Novo, Mercedes; Al-Soufi, Wajih

    2010-05-15

    The dynamics of the exchange of the moderately hydrophobic neutral dye Coumarine 152 between the aqueous phase and the phase formed by neutral Triton X-100 micelles is studied by Fluorescence Correlation Spectroscopy. The changes in the photophysical properties of the dye in presence of the micelles are discussed. The low quantum yield, the low saturation threshold and the necessary high energetic excitation of this dye requires a careful selection of the experimental conditions in order to obtain dynamic and diffusional properties with reasonable precision. It is shown that the contrast between the brightness of free and bound dye has a strong influence on the sensitivity of the FCS experiment. The entry rate constant of the dye to the micelles, k(+)=(0.8±0.3)×10(10) M(-1) s(-1), is very near to the diffusion controlled limit. The high association equilibrium constant of K=(129±3)×10(3) M(-1) is mainly determined by the low exit rate constant, k(-)=(0.6±0.2)×10(5) s(-1). Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Electrothermal atomization laser-excited atomic fluorescence spectroscopy for the determination of indium

    International Nuclear Information System (INIS)

    Aucelio, R.Q.; Smith, B.W.; Winefordner, J.D.

    1998-01-01

    A dye laser pumped by a high-repetition-rate copper vapor laser was used as the excitation source to determine indium at parts-per-trillion level by electrothermal atomization laser-excited atomic fluorescence spectrometry (ETA-LEAFS). A comparison was made between wall atomization, in pyrolytic and nonpyrolytic graphite tubes, and platform atomization. The influence of several chemical modifiers either in solution or precoated in the graphite tube was evaluated. The influence of several acids and NaOH in the analyte solution was also studied. Optimization of the analytical conditions was carried out to achieve the best signal-to-background ratio and consequently an absolute limit of detection of 1 fg. Some possible interferents of the method were evaluated. The method was evaluated by determining indium in blood, urine, soil, and urban dust samples. Recoveries between 99.17 and 109.17% are reported. A precision of 4.1% at the 10 ng g -1 level in water standards was achieved. copyright 1998 Society for Applied Spectroscopy

  7. Conformation and dynamics of nucleotides in bulges and symmetric internal loops in duplex DNA studied by EPR and fluorescence spectroscopies

    International Nuclear Information System (INIS)

    Cekan, Pavol; Sigurdsson, Snorri Th.

    2012-01-01

    Highlights: ► Bulges and loops were studied by both EPR and fluorescence spectroscopies using the probe Ç/Ç f . ► One-base bulge was in a temperature-dependent equilibrium between looped-out and stacked states. ► Bases in two- and three-base bulges were stacked at all temperatures, resulting in DNA bending. ► Bases were stacked in symmetrical two- to five-base internal loops, according to EPR data. ► Unexpectedly high fluorescence for the smaller loops indicated local structural perturbations. -- Abstract: The dynamics and conformation of base bulges and internal loops in duplex DNA were studied using the bifunctional spectroscopic probe Ç, which becomes fluorescent (Ç f ) upon reduction of the nitroxide functional group, along with EPR and fluorescence spectroscopies. A one-base bulge was in a conformational equilibrium between looped-out and stacked states, the former favored at higher temperature and the latter at lower temperature. Stacking of bulge bases was favored in two- and three-base bulges, independent of temperature, resulting in DNA bending as evidenced by increased fluorescence of Ç f . EPR spectra of Ç-labeled three-, four- and five-base symmetrical interior DNA bulges at 20 °C showed low mobility, indicating that the spin-label was stacked within the loop. The spin-label mobility at 37 °C increased as the loops became larger. A considerable variation in fluorescence between different loops was observed, as well as a temperature-dependence within constructs. Fluorescence unexpectedly increased as the size of the loop decreased at 2 °C. Fluorescence of the smallest loops, where a single T·T mismatch was located between the stem region and the probe, was even larger than for the single strand, indicating a considerable local structural deformation of these loops from regular B-DNA. These results show the value of combining EPR and fluorescence spectroscopy to study non-helical regions of nucleic acids.

  8. Decay time shortening of fluorescence from donor-acceptor pair proteins using ultrafast time-resolved fluorescence resonance energy transfer spectroscopy

    International Nuclear Information System (INIS)

    Baba, Motoyoshi; Suzuki, Masayuki; Ganeev, Rashid A.; Kuroda, Hiroto; Ozaki, Tsuneyuki; Hamakubo, Takao; Masuda, Kazuyuki; Hayashi, Masahiro; Sakihama, Toshiko; Kodama, Tatsuhiko; Kozasa, Tohru

    2007-01-01

    We improved an ultrafast time-resolved fluorescence resonance energy transfer (FRET) spectroscopy system and measured directly the decrease in the fluorescence decay time of the FRET signal, without any entanglement of components in the picosecond time scale from the donor-acceptor protein pairs (such as cameleon protein for calcium ion indicator, and ligand-activated GRIN-Go proteins pair). The drastic decrease in lifetime of the donor protein fluorescence under the FRET condition (e.g. a 47.8% decrease for a GRIN-Go protein pair) proves the deformation dynamics between donor and acceptor fluorescent proteins in an activated state of a mixed donor-acceptor protein pair. This study is the first clear evidence of physical contact of the GRIN-Go proteins pair using time-resolved FRET system. G protein-coupled receptors (GPCRs) are the most important protein family for the recognition of many chemical substances at the cell surface. They are the targets of many drugs. Simultaneously, we were able to observe the time-resolved spectra of luminous proteins at the initial stage under the FRET condition, within 10 ns from excitation. This new FRET system allows us to trace the dynamics of the interaction between proteins at the ligand-induced activated state, molecular structure change and combination or dissociation. It will be a key technology for the development of protein chip technology

  9. Spectral characterization of crude oil using fluorescence (synchronous and time-resolved) and NIR (Near Infrared Spectroscopy); Caracterizacao espectral do petroleo utilizando fluorescencia (sincronizada e resolvida no tempo) e NIR (Near Infrared Spectroscopy)

    Energy Technology Data Exchange (ETDEWEB)

    Falla Sotelo, F.; Araujo Pantoja, P.; Lopez-Gejo, J.; Le Roux, G.A.C.; Nascimento, C.A.O. [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Quimica. Lab. de Simulacao e Controle de Processos; Quina, F.H. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Centro de Capacitacao e Pesquisa em Meio Ambiente (CEPEMA)

    2008-07-01

    The objective of the present work is to evaluate the performance of two spectroscopic techniques employed in the crude oil characterization: NIR spectroscopy and fluorescence spectroscopy (Synchronous fluorescence - SF and Time Resolved Fluorescence - TRF) for the development of correlation models between spectral profiles of crude oil samples and both physical properties (viscosity and API density) and physico-chemical properties (SARA analysis: Saturated, Aromatic, Resins and Asphaltenes). The better results for viscosity and density were obtained using NIR whose prediction capacity was good (1.5 cP and 0.5 deg API, respectively). For SARA analysis, fluorescence spectroscopy revealed its potential in the model calibration showing good results (R2 coefficients greater than 0.85). TRF spectroscopy had better performance than SF spectroscopy. (author)

  10. Defining a turnover index for the correlation of biomaterial degradation and cell based extracellular matrix synthesis using fluorescent tagging techniques.

    Science.gov (United States)

    Bardsley, Katie; Wimpenny, Ian; Wechsler, Roni; Shachaf, Yonatan; Yang, Ying; El Haj, Alicia J

    2016-11-01

    Non-destructive protocols which can define a biomaterial's degradation and its associated ability to support proliferation and/or promote extracellular matrix deposition will be an essential in vitro tool. In this study we investigate fluorescently tagged biomaterials, with varying rates of degradation and their ability to support cell proliferation and osteogenic differentiation. Changes in fluorescence of the biomaterials and the release of fluorescent soluble by-products were confirmed as accurate methods to quantify degradation. It was demonstrated that increasing rates of the selected biomaterials' degradation led to a decrease in cell proliferation and concurrently an increase in osteogenic matrix production. A novel turnover index (TI), which directly describes the effect of degradation of a biomaterial on cell behaviour, was calculated. Lower TIs for proliferation and high TIs for osteogenic marker production were observed on faster degrading biomaterials, indicating that these biomaterials supported an upregulation of osteogenic markers. This TI was further validated using an ex vivo chick femur model, where the faster degrading biomaterial, fibrin, led to an increased TI for mineralisation within an epiphyseal defect. This in vitro tool, TI, for monitoring the effect of biomaterial degradation on extracellular matrix production may well act as predictor of the selected biomaterials' performance during in vivo studies. This paper outlines a novel metric, Turnover Index (TI), which can be utilised in tissue-engineering for the comparison of a range of biomaterials. The metric sets out to define the relationship between the rate of degradation of biomaterials with the rate of cell proliferation and ECM synthesis, ultimately allowing us to tailor material for set clinical requirements. We have discovered some novel comparative findings that cells cultured on biomaterials with increased rates of degradation have lower rates of proliferation but alternatively

  11. A Literature Study of Matrix Element Influenced to the Result of Analysis Using Absorption Atomic Spectroscopy Method (AAS)

    International Nuclear Information System (INIS)

    Tyas-Djuhariningrum

    2004-01-01

    The gold sample analysis can be deviated more than >10% to those thrue value caused by the matrix element. So that the matrix element character need to be study in order to reduce the deviation. In rock samples, the matrix elements can cause self quenching, self absorption and ionization process, so there is a result analysis error. In the rock geochemical process, the elements of the same group at the periodic system have the tendency to be together because of their same characteristic. In absorption Atomic Spectroscopy analysis, the elements associate can absorb primer energy with similar wave length so that it can cause deviation in the result interpretation. The aim of study is to predict matrix element influences from rock sample with application standard method for reducing deviation. In quantitative way, assessment of primer light intensity that will be absorbed is proportional to the concentration atom in the sample that relationship between photon intensity with concentration in part per million is linier (ppm). These methods for eliminating matrix elements influence consist of three methods : external standard method, internal standard method, and addition standard method. External standard method for all matrix element, internal standard method for elimination matrix element that have similar characteristics, addition standard methods for elimination matrix elements in Au, Pt samples. The third of standard posess here accuracy are about 95-97%. (author)

  12. Mechanisms of ultrafast fluorescence depletion spectroscopy and applications to measure slovation dynamics of coummarin 153 in methanol

    International Nuclear Information System (INIS)

    Yang Songqiu; Liu Jianyong; Zhou Panwang; Chen Junsheng; Han Keli; He Guozhong

    2012-01-01

    Subpicosecond fluorescence depletion spectroscopy (FDS) was used to measure the solvation dynamics of coumarin 153 (C153) in methanol. The FDS mechanisms were discussed. A quasi-continuous model was used to describe the solvational relaxation of excited states. The perturbations of the probe pulse on the excited sample system, including up-conversion and stimulated emission, were sufficiently discussed. For a probe molecule used in the FDS experiment, ensuring that the up-conversion perturbation can be negligible is important. FDS was found to be a good technique for measuring the solvation dynamics of C153 in methanol. - Highlights: ► Mechanisms of subpicosecond fluorescence depletion spectroscopy. ► Quasi-continuous model was used to describe the solvational relaxation. ► The solvation dynamics of coumarin 153 in methanol has been measured.

  13. Interaction of fisetin with human serum albumin by fluorescence, circular dichroism spectroscopy and DFT calculations: binding parameters and conformational changes

    International Nuclear Information System (INIS)

    Matei, Iulia; Ionescu, Sorana; Hillebrand, Mihaela

    2011-01-01

    The interaction between fisetin, an antioxidant and neuroprotective flavonoid, and human serum albumin (HSA) is investigated by means of fluorescence (steady-state, synchronous, time-resolved) and circular dichroism (CD) spectroscopy. The formation of a 1:1 complex with a constant of about 10 5 M -1 was evidenced. Foerster's resonance energy transfer and competitive binding with site markers warfarin and ibuprofen were considered and discussed. Changes in the CD band of HSA indicate a decrease in the α-helix content upon binding. An induced CD signal for bound fisetin was observed and rationalized in terms of density functional theory calculations. - Highlights: → Fisetin-BSA system was studied by fluorescence spectroscopy. → Binding parameters, association constant and number of sites were estimated. → Binding site of fisetin was identified by competitive experiments. → Conformational changes in HSA and fisetin were evidenced by circular dichroism. → TDDFT calculated CD spectra supported the experimental data.

  14. Interaction of fisetin with human serum albumin by fluorescence, circular dichroism spectroscopy and DFT calculations: binding parameters and conformational changes

    Energy Technology Data Exchange (ETDEWEB)

    Matei, Iulia; Ionescu, Sorana [Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, 030018 Bucharest (Romania); Hillebrand, Mihaela, E-mail: mihh@gw-chimie.math.unibuc.ro [Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, 030018 Bucharest (Romania)

    2011-08-15

    The interaction between fisetin, an antioxidant and neuroprotective flavonoid, and human serum albumin (HSA) is investigated by means of fluorescence (steady-state, synchronous, time-resolved) and circular dichroism (CD) spectroscopy. The formation of a 1:1 complex with a constant of about 10{sup 5} M{sup -1} was evidenced. Foerster's resonance energy transfer and competitive binding with site markers warfarin and ibuprofen were considered and discussed. Changes in the CD band of HSA indicate a decrease in the {alpha}-helix content upon binding. An induced CD signal for bound fisetin was observed and rationalized in terms of density functional theory calculations. - Highlights: > Fisetin-BSA system was studied by fluorescence spectroscopy. > Binding parameters, association constant and number of sites were estimated. > Binding site of fisetin was identified by competitive experiments. > Conformational changes in HSA and fisetin were evidenced by circular dichroism. > TDDFT calculated CD spectra supported the experimental data.

  15. The characterisation of molecular boric acid by mass spectrometry and matrix isolation-infrared spectroscopy

    International Nuclear Information System (INIS)

    Ogden, J.S.; Young, N.A.; Bowsher, B.R.

    1987-10-01

    Boric acid (H 3 BO 3 ) is used as a soluble neutron absorber in the coolant of pressurised water reactors and will be an important species in defining the fission product chemistry of severe reactor accidents. Mass spectrometry and matrix isolation-infrared spectroscopy have been used to characterise boric acid in the vapour phase and hence assess the implications of any chemical interactions. Crystalline orthoboric acid vaporises to yield molecular H 3 BO 3 when heated in vacuum to approximately 40 0 C. The infrared spectrum of the vapour species isolated in low-temperature nitrogen matrices shows characteristic absorptions at 3668.5 (E'), 1426.2 (E'), 1009.9 (E'), 675.0 (A''), 513.8 (A'') and 448.9 (E') cm -1 , consistent with C 3h symmetry. These spectral assignments are supported by extensive isotope labelling, and by a partial normal co-ordinate analysis. These data will be used to quantify specific thermodynamic functions and hence assist in determining the magnitude of reactions such as boric acid with caesium iodide. (author)

  16. A pH dependence study of CdTe quantum dots fluorescence quantum yields using eclipsing thermal lens spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Estupiñán-López, C. [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Dominguez, C. Tolentino [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Centre for Telecommunication Studies, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Filho, P.E. Cabral [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Biophysics and Radiobiology Department, Federal University of Pernambuco, Recife, PE (Brazil); Santos, B.S. [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Pharmaceutical Sciences Department, Federal University of Pernambuco, Recife, PE (Brazil); Fontes, A., E-mail: adriana.fontes.biofisica@gmail.com [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil); Biophysics and Radiobiology Department, Federal University of Pernambuco, Recife, PE (Brazil); Araujo, R.E. de, E-mail: renato.earaujo@ufpe.br [Laboratory of Biomedical Optics and Imaging, Federal University of Pernambuco, Recife, PE (Brazil)

    2016-06-15

    In this study we evaluated the absolute fluorescence quantum yield (Φ) of hydrophilic CdTe QDs in function of different pHs, modified from the alkaline to acid, by using two different chemicals compounds, the mercaptosuccinic acid (MSA-the stabilizing agent of the QDs synthesis) or hydrochloric acid (HCl). The pH control of QDs suspensions is essential for the use of fluorescent nanoparticles in biological systems. We used the eclipsing thermal lens spectroscopy technique to determine the absolute fluorescence quantum yield values. The results showed variations on the Φ values as a function of the pH, which allowed a better understanding of QDs emission characteristics, establishing parameters for their use in biomedical applications such as optical images of biological systems, immunoassays, flow cytometry, biosensors and others.

  17. Two dimensional laser induced fluorescence in the gas phase: a spectroscopic tool for studying molecular spectroscopy and dynamics

    Science.gov (United States)

    Gascooke, Jason R.; Lawrance, Warren D.

    2017-11-01

    Two dimensional laser induced fluorescence (2D-LIF) extends the usual laser induced fluorescence technique by adding a second dimension, the wavelength at which excited states emit, thereby significantly enhancing the information that can be extracted. It allows overlapping absorption features, whether they arise from within the same molecule or from different molecules in a mixture, to be associated with their appropriate "parent" state and/or molecule. While the first gas phase version of the technique was published a decade ago, the technique is in its infancy, having been exploited by only a few groups to date. However, its potential in gas phase spectroscopy and dynamics is significant. In this article we provide an overview of the technique and illustrate its potential with examples, with a focus on those utilising high resolution in the dispersed fluorescence dimension.

  18. Delta-ALA-mediated fluorescence spectroscopy of gastrointestinal tumors: comparison of in vivo and in vitro results

    Science.gov (United States)

    Vladimirov, B.; Borisova, E.; Avramov, L.

    2007-06-01

    The limitations of standard endoscopy for detection of dysplastic changes of mucosa are significant challenge and initiate development of new photodiagnostic techniques, additional to diagnostic possibilities of standard endoscopic equipment. One of the most widely examined optical modalities is the laser- or light-induced fluorescence spectroscopy (LIFS), because of its rapid and highly sensitive response to early biochemical and morphological changes in biological tissues. In the recent study delta-aminolevulinic acid/protoporphyrin IX is used as fluorescent marker for dysplasia and tumor detection in esophagus and stomach. The δ -ALA is administered per os six hours before measurements at dose 20mg/kg weight. High-power light-emitting diode at 405 nm is used as an excitation source. Special opto-mechanical device is built to use the light guide of standard video-endoscopic system. Through endoscopic instrumental channel a fiber is applied to return information about fluorescence to microspectrometer. The fluorescence detected from in vivo tumor sites has very complex spectral origins. It consists of autofluorescence, fluorescence from exogenous fluorophores and re-absorption from the chromophores accumulated in the tissue investigated. Mucosa autofluorescence lies at 450-600 nm region. The fluorescence of PpIX is clearly pronounced at the 630-710 nm region. Deep minima in the tumor fluorescence signals are observed in the region 540-575 nm, related to hemoglobin re-absorption. Such high hemoglobin content is an indication of the tumors vascularization and it is clearly pronounced in all dysplastic and tumor sites investigated. After formalin conservation for in vitro samples hemoglobin absorption is strongly reduced that increases mucous fluorescence signal in green-yellow spectral region. Simultaneously the maxima at 635 nm and 720 nm are reduced.

  19. Synchrotron Radiation Total Reflection X-ray Fluorescence Spectroscopy for Microcontamination Analysis on Silicon Wafer Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Takaura, Norikatsu

    1997-10-01

    As dimensions in state-of-the-art CMOS devices shrink to less than 0.1 pm, even low levels of impurities on wafer surfaces can cause device degradation. Conventionally, metal contamination on wafer surfaces is measured using Total Reflection X-Ray Fluorescence Spectroscopy (TXRF). However, commercially available TXRF systems do not have the necessary sensitivity for measuring the lower levels of contamination required to develop new CMOS technologies. In an attempt to improve the sensitivity of TXRF, this research investigates Synchrotron Radiation TXRF (SR TXRF). The advantages of SR TXRF over conventional TXRF are higher incident photon flux, energy tunability, and linear polarization. We made use of these advantages to develop an optimized SR TXRF system at the Stanford Synchrotron Radiation Laboratory (SSRL). The results of measurements show that the Minimum Detection Limits (MDLs) of SR TXRF for 3-d transition metals are typically at a level-of 3x10{sup 8} atoms/cm{sup 2}, which is better than conventional TXRF by about a factor of 20. However, to use our SR TXRF system for practical applications, it was necessary to modify a commercially available Si (Li) detector which generates parasitic fluorescence signals. With the modified detector, we could achieve true MDLs of 3x10{sup 8} atoms/cm{sup 2} for 3-d transition metals. In addition, the analysis of Al on Si wafers is described. Al analysis is difficult because strong Si signals overlap the Al signals. In this work, the Si signals are greatly reduced by tuning the incident beam energy below the Si K edge. The results of our measurements show that the sensitivity for Al is limited by x-ray Raman scattering. Furthermore, we show the results of theoretical modeling of SR TXRF backgrounds consisting of the bremsstrahlung generated by photoelectrons, Compton scattering, and Raman scattering. To model these backgrounds, we extended conventional theoretical models by taking into account several aspects particular

  20. Speciation of bioaccumulated uranium(VI) by Euglena mutabilis cells obtained by laser fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, Sina; Bernhard, Gert [Technical Univ. Dresden (Germany). Radiochemistry; Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology; Arnold, Thuro [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology

    2014-07-01

    The ability of Euglena mutabilis cells - a unicellular protozoan with a flexible pellicle, which is typically found in acid mine drainage (AMD) environments - to bioaccumulate uranium under acid conditions was studied in batch sorption experiments at pH 3 and 4 using Na{sub 2}SO{sub 4} and NaClO{sub 4} as background media. It was found that axenic cultures of Euglena mutabilis Schmitz were able to bioaccumulate in 5 days 94.9 to 99.2% of uranium from a 1 x 10{sup -5} mol/L uranium solution in perchlorate medium and 95.1 to 95.9% in sodium sulfate medium, respectively. The speciation of uranium in solution and uranium bioaccumulated by Euglena mutabilis cells, were studied by laser induced fluorescence spectroscopy (LIFS). The LIFS investigations showed that the uranium speciation in the NaClO{sub 4} systems was dominated by free uranyl(VI) species and that the UO{sub 2}SO{sub 4} species was dominating in the Na{sub 2}SO{sub 4} medium. Fluorescence spectra of the bioaccumulated uranium revealed that aqueous uranium binds to carboxylic and/or (organo)phosphate groups located on the euglenid pellicle or inside the Euglena mutabilis cells. Reduced uranium immobilization rates of 0.93-1.43 mg uranium per g Euglena mutabilis biomass were observed in similar experiments, using sterile filtrated AMD waters containing, 4.4 x 10{sup -5} mol/L uranium. These lower rates were attributed to competition with other cations for available sorption sites. Additional LIFS measurements, however, showed that the speciation of the bioaccumulated uranium by the Euglena mutabilis cells was found to be identical with the uranium speciation found in the bioaccumulation experiments carried out in Na{sub 2}SO{sub 4} and NaClO{sub 4} media. The results indicate that Euglena mutabilis has the potential to immobilize aqueous uranium under acid condition and thus may be used in future as promising agent for immobilizing uranium in low pH waste water environments. (orig.)

  1. Speciation of bioaccumulated uranium(VI) by Euglena mutabilis cells obtained by laser fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Brockmann, Sina; Bernhard, Gert; Helmholtz-Zentrum Dresden-Rossendorf; Arnold, Thuro

    2014-01-01

    The ability of Euglena mutabilis cells - a unicellular protozoan with a flexible pellicle, which is typically found in acid mine drainage (AMD) environments - to bioaccumulate uranium under acid conditions was studied in batch sorption experiments at pH 3 and 4 using Na 2 SO 4 and NaClO 4 as background media. It was found that axenic cultures of Euglena mutabilis Schmitz were able to bioaccumulate in 5 days 94.9 to 99.2% of uranium from a 1 x 10 -5 mol/L uranium solution in perchlorate medium and 95.1 to 95.9% in sodium sulfate medium, respectively. The speciation of uranium in solution and uranium bioaccumulated by Euglena mutabilis cells, were studied by laser induced fluorescence spectroscopy (LIFS). The LIFS investigations showed that the uranium speciation in the NaClO 4 systems was dominated by free uranyl(VI) species and that the UO 2 SO 4 species was dominating in the Na 2 SO 4 medium. Fluorescence spectra of the bioaccumulated uranium revealed that aqueous uranium binds to carboxylic and/or (organo)phosphate groups located on the euglenid pellicle or inside the Euglena mutabilis cells. Reduced uranium immobilization rates of 0.93-1.43 mg uranium per g Euglena mutabilis biomass were observed in similar experiments, using sterile filtrated AMD waters containing, 4.4 x 10 -5 mol/L uranium. These lower rates were attributed to competition with other cations for available sorption sites. Additional LIFS measurements, however, showed that the speciation of the bioaccumulated uranium by the Euglena mutabilis cells was found to be identical with the uranium speciation found in the bioaccumulation experiments carried out in Na 2 SO 4 and NaClO 4 media. The results indicate that Euglena mutabilis has the potential to immobilize aqueous uranium under acid condition and thus may be used in future as promising agent for immobilizing uranium in low pH waste water environments. (orig.)

  2. Multimodal Raman-fluorescence spectroscopy of formalin fixed samples is able to discriminate brain tumors from dysplastic tissue

    Science.gov (United States)

    Anand, Suresh; Cicchi, Riccardo; Giordano, Flavio; Buccoliero, Anna Maria; Pavone, Francesco Saverio

    2014-05-01

    In the recent years, there has been a considerable surge in the application of spectroscopy for disease diagnosis. Raman and fluorescence spectra provide characteristic spectral profile related to biochemical and morphological changes when tissues progress from normal state towards malignancy. Spectroscopic techniques offer the advantage of being minimally invasive compared to traditional histopathology, real time and quantitative. In biomedical optical diagnostics, freshly excised specimens are preferred for making ex-vivo spectroscopic measurements. With regard to fresh tissues, if the lab is located far away from the clinic it could pose a problem as spectral measurements have to be performed immediately after dissection. Tissue samples are usually placed in a fixative agent such as 4% formaldehyde to preserve the samples before processing them for routine histopathological studies. Fixation prevents the tissues from decomposition by arresting autolysis. In the present study, we intend to investigate the possibility of using formalin fixed samples for discrimination of brain tumours from dysplastic tissue using Raman and fluorescence spectroscopy. Formalin fixed samples were washed with phosphate buffered saline for about 5 minutes in order to remove the effects of formalin during spectroscopic measurements. In case of fluorescence spectroscopy, changes in spectral profile have been observed in the region between 550-670 nm between dysplastic and tumor samples. For Raman measurements, we found significant differences in the spectral profiles between dysplasia and tumor. In conclusion, formalin fixed samples can be potentially used for the spectroscopic discrimination of tumor against dysplastic tissue in brain samples.

  3. Study of tryptophan assisted synthesis of gold nanoparticles by combining UV-Vis, fluorescence, and SERS spectroscopy

    International Nuclear Information System (INIS)

    Iosin, Monica; Baldeck, Patrice; Astilean, Simion

    2010-01-01

    We developed a rapid and non-toxic method for the preparation of colloidal gold nanoparticles (GNPs) by using tryptophan (Trp) as reducing/stabilizing agent. We show that the temperature has a major influence on the kinetics of gold ion reduction and the crystal growth, higher temperatures favoring the synthesis of anisotropic nanoparticles (triangles and hexagons). The as-synthesized nanostructures were characterized by UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), fluorescence, and surface-enhanced Raman scattering (SERS) spectroscopy. The UV-Vis measurements confirmed that temperature is a critical factor in the synthesis process, having a major effect on the shape of the synthesized GNPs. Moreover, fluorescence spectroscopy was able to monitor the quenching of the Trp fluorescence during the in situ synthesis of GNPs. Using Trp as molecular analyte to evaluate the SERS efficiency of as-prepared GNPs at different temperatures, we demonstrated that the Raman enhancement of the synthesized gold nanoplates is higher than that of the gold spherical nanoparticles.

  4. Ultraviolet-visible and fluorescence spectroscopy can be used as a diagnostic tool for gamma irradiation detection in vivo.

    Science.gov (United States)

    K-Abdelhalim, Mohamed Anwar; Moussa, Sherif A-Abdelmottaleb

    2016-09-01

    The spectroscopic properties can indicate important features about the nature and severity of the disease. However, no earlier studies have been used the spectroscopic properties as a diagnostic tool for radiation detection. This study was aimed to use ultraviolet-visible and fluorescence spectroscopy as a diagnostic tool for gamma irradiation detection in rats in vivo. Adult male rats were exposed to 25, 50, 75 and 100 Gray as single dose, using Cobalt-60 (Co-60) source with a dose rate of 0.883 centi Gray/sec (cGy/s). Ultraviolet and fluorescence spectroscopy of rat's blood serum were measured. After gamma irradiation of rats in vivo, the blood serum absorbance peaks for 25, 50, 75 and 100 Gray (Gy) decreased and shifted towards the ultra violet wavelength. A maximal change in fluorescence intensity of blood serum at 350 nm was obtained when exciting light at 194 nm after irradiation. The fluorescence intensity also decreased with the dose. The highest radiation gamma dose might be accompanied with the highest oxidative stress. This study suggests that at the above mentioned gamma radiation doses, the blood is highly fragmented; with low aggregation at 25 Gy and with high aggregation at 50-100 Gy.

  5. A general X-ray fluorescence spectrometric technique based on simple corrections for matrix effects

    International Nuclear Information System (INIS)

    Kruidhof, H.

    1978-01-01

    The method reported, which is relatively simple and generally applicable for most materials, involves a combination of borax fusion with matrix effect corrections. The latter are done with algorithms, which are derived from the intensity formulae, together with empirical coefficients. (Auth.)

  6. Detecting aromatic compounds on planetary surfaces using ultraviolet time-resolved fluorescence spectroscopy

    Science.gov (United States)

    Eshelman, E.; Daly, M. G.; Slater, G.; Cloutis, E.

    2018-02-01

    Many aromatic organic molecules exhibit strong and characteristic fluorescence when excited with ultraviolet radiation. As laser excitation in the ultraviolet generates both fluorescence and resonantly enhanced Raman scattering of aromatic vibrational modes, combined Raman and fluorescence instruments have been proposed to search for organic compounds on Mars. In this work the time-resolved fluorescence of a suite of 24 compounds composed of 2-5 ringed alternant, non-alternant, and heterocyclic PAHs was measured. Fluorescence instrumentation with similar specifications to a putative flight instrument was capable of observing the fluorescence decay of these compounds with a sub-ns resolution. Incorporating time-resolved capabilities was also found to increase the ability to discriminate between individual PAHs. Incorporating time-resolved fluorescence capabilities into an ultraviolet gated Raman system intended for a rover or lander can increase the ability to detect and characterize PAHs on planetary surfaces.

  7. Combining mid infrared and total X-ray fluorescence spectroscopy for prediction of soil properties

    Science.gov (United States)

    Towett, Erick; Shepherd, Keith; Sila, Andrew; Aynekulu, Ermias; Cadisch, Georg

    2015-04-01

    Mid-infrared diffuse reflectance spectroscopy (MIR) can predict many soil properties but extractable nutrients are often predicted poorly. We evaluated the potential of MIR and total elemental analysis using total X-ray fluorescence spectroscopy (TXRF), both individually and combined, to predict results of conventional soil tests. Total multi-elemental analysis provides a fingerprint of soil mineralogy and could predict some soil properties and help improve MIR predictions. A set of 700 georeferenced soil samples associated with the Africa Soil Information Service (AfSIS) (www.africasoils.net) from 44 stratified randomly-located 100-km2 sentinel sites distributed across sub-Saharan Africa were analysed for physico-chemical composition using conventional reference methods, and compared to MIR and TXRF spectra using the Random Forests regression algorithm and an internal out-of-bag validation. MIR spectra resulted in good prediction models (R2 >0.80) for organic C and total N, Mehlich-3 Ca and Al, and pH. To test the combined spectroscopic approach, TXRF element concentration data was included as a property predictor along with the first derivative of MIR spectral data using the RF algorithm. Including TXRF did not improve prediction of these properties. TXRF was poorer (R2 0.86) as these elements are not directly determined with TXRF, however the variance explained is still quite high and may be attributable to TXRF signatures relating to mineralogy correlated with protection of soil organic matter. TXRF model for Mehlich-3 Al had excellent prediction capability explaining 81% of the observed variation in extractable Al content and was comparable to that of MIR (R2 = 0.86). However, models for pH and Mehlich-3 exchangeable Ca exhibited R2 values of 0.74 and 0.79 respectively and thus had moderate predictive accuracy, compared to MIR alone with R2 values of 0.82 and 0.84 respectively. Both MIR and TXRF methods predicted soil properties that relate to nutrient

  8. Quantitative multi-color FRET measurements by Fourier lifetime excitation-emission matrix spectroscopy

    Science.gov (United States)

    Zhao, Ming; Huang, Run; Peng, Leilei

    2012-01-01

    Förster resonant energy transfer (FRET) is extensively used to probe macromolecular interactions and conformation changes. The established FRET lifetime analysis method measures the FRET process through its effect on the donor lifetime. In this paper we present a method that directly probes the time-resolved FRET signal with frequency domain Fourier lifetime excitation-emission matrix (FLEEM) measurements. FLEEM separates fluorescent signals by their different phonon energy pathways from excitation to emission. The FRET process generates a unique signal channel that is initiated by donor excitation but ends with acceptor emission. Time-resolved analysis of the FRET EEM channel allows direct measurements on the FRET process, unaffected by free fluorophores that might be present in the sample. Together with time-resolved analysis on non-FRET channels, i.e. donor and acceptor EEM channels, time resolved EEM analysis allows precise quantification of FRET in the presence of free fluorophores. The method is extended to three-color FRET processes, where quantification with traditional methods remains challenging because of the significantly increased complexity in the three-way FRET interactions. We demonstrate the time-resolved EEM analysis method with quantification of three-color FRET in incompletely hybridized triple-labeled DNA oligonucleotides. Quantitative measurements of the three-color FRET process in triple-labeled dsDNA are obtained in the presence of free single-labeled ssDNA and double-labeled dsDNA. The results establish a quantification method for studying multi-color FRET between multiple macromolecules in biochemical equilibrium. PMID:23187535

  9. Study of Organic Matter in Soils of the Amazon Region Employing Laser Induced Fluorescence Spectroscopy

    Science.gov (United States)

    Tadini, Amanda Maria; Nicolodelli, Gustavo; Mounier, Stéphane; Montes, Célia Regina; Marcondes Bastos Pereira Milori, Débora

    2014-05-01

    In the face of climate change and increasing CO2 levels in the atmosphere, the global carbon cycle, soil organic carbon (SOC) sequestration, and the role of different world biomes as potential sources and sinks of carbon are receiving increasing attention. Carbon quantification is an important environmental indicator, but the structure of organic matter is also important because is related to carbon stability. The synthesis of soil organic matter (SOM), as presented in soils of forest vegetation, can be originated from condensation polymeric polyphenols and quinones that are responsible for controlling the main physical-chemical properties of soils. These systems are present in humic substances, representing the major fluorophore of SOM[1-3]. Abiotic factors, such as soil texture, use and occupation of soil, can influence on the process of SOM formation, molecular structure and in its humification index[4]. Laser Induced Fluorescence Spectroscopy (LIFS) have become a promising technique for assessing humification index of SOM (HLIFS). In this context, the aim of this study was to analyze the humification index of the SOM in the region of Barcelos (Amazon) employing LIFS. The study area was the region of Barcelos, close the river Demeni. The whose vegetation distribution in this area, is two biomes the Dense Ombrophylous Forest (DPQD) and Campinarana (DPQT), with areas of edaphic contacts between these two phytophysiognomies, which ranged from Open field (FDE) to closed Depression (DPQ). Preliminary results showed that the area closed Depression (DPQ) there was a continuous gradient of humification with increasing soil depth. A similar behavior was verified for area Forest (DPQD), where the highest values of HLIFS were obtained between the four points analyzed, indicating the magnitude of the molecular recalcitrance this organic matter in this area. The results obtained for area Campinarana (DPQT) and Open field (FDE) showed an opposite behavior. These points there

  10. Resonant inelastic scattering in dilute magnetic semiconductors by x-ray fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lawniczak-Jablonska, K. [Lawrence Berkeley National Lab., CA (United States)]|[Institute of Physics, Warsaw (Poland); Jia, J.J.; Underwood, J.H. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    As modern, technologically important materials have become more complex, element specific techniques have become invaluable in studying the electronic structure of individual components from the system. Soft x-ray fluorescence (SXF) and absorption (SXA) spectroscopies provide a unique means of measuring element and angular momentum density of electron states, respectively, for the valence and conducting bands in complex materials. X-ray absorption and the decay through x-ray emission are generally assumed to be two independent one-photon processes. Recent studies, however have demonstrated that SXF excited near the absorption threshold generate an array of spectral features that depend on nature of materials, particularly on the localization of excited states in s and d-band solids and that these two processes can no be longer treated as independent. Resonant SXF offers thus the new way to study the dynamics of the distribution of electronic valence states in the presence of a hole which is bound to the electron low lying in the conduction band. This process can simulate the interaction between hole-electron pair in wide gap semiconductors. Therefore such studies can help in understanding of transport and optics phenomena in the wide gap semiconductors. The authors report the result of Mn and S L-resonant emission in Zn{sub 1{minus}x}Mn{sub x}S (with x=0.2 and 0.3) and MnS as the energy of exciting radiation is tuned across the Mn and S L{sub 3,2} absorption edge, along with the resonant excited spectra from elemental Mn as a reference.

  11. Fluorescence correlation spectroscopy diffusion laws in the presence of moving nanodomains

    International Nuclear Information System (INIS)

    Šachl, Radek; Hof, Martin; Bergstrand, Jan; Widengren, Jerker

    2016-01-01

    It has been shown by means of simulations that spot variation fluorescence correlation spectroscopy (sv-FCS) can be used for the identification and, to some extent, also characterization of immobile lipid nanodomains in model as well as cellular plasma membranes. However, in these simulations, the nanodomains were assumed to be stationary, whereas they actually tend to move like the surrounding lipids. In the present study, we investigated how such domain movement influences the diffusion time/spot-size dependence observed in FCS experiments, usually referred to as ‘diffusion law’ analysis. We show that domain movement might mask the effects of the ‘anomalous’ diffusion characteristics of membrane lipids or proteins predicted for stationary domains, making it difficult to identify such moving nanodomains by sv-FCS. More specifically, our simulations indicate that (i) for domains moving up to a factor of 2.25 slower than the surrounding lipids, such impeded diffusion cannot be observed and the diffusion behaviour of the proteins or lipids is indistinguishable from that of freely diffusing molecules, i.e. nanodomains are not detected; (ii) impeded protein/lipid diffusion behaviour can be observed in experiments where the radii of the detection volume are similar in size to the domain radii, the domain diffusion is about 10 times slower than that of the lipids, and the probes show a high affinity to the domains; and (iii) presence of nanodomains can only be reliably detected by diffraction limited sv-FCS when the domains move very slowly (about 200 times slower than the lipid diffusion). As nanodomains are expected to be in the range of tens of nanometres and most probes show low affinities to such domains, sv-FCS is limited to stationary domains and/or STED-FCS. However, even for that latter technique, diffusing domains smaller than 50 nm in radius are hardly detectable by FCS diffusion time/spot-size dependencies. (paper)

  12. Generation of a new spectral format, the lifetime synchronous spectrum (LiSS), using phase-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Shaver, J.M.; McGown, L.B.

    1994-01-01

    A new fluorescence spectral format is introduced in which fluorescence lifetime is shown as a function of synchronously scanned wavelength to generate a Lifetime Synchronous Spectrum (LiSS). Lifetimes are determined in the frequency domain with the use of Phase-Resolved Fluorescence Spectroscopy (PRFS) to obtain the phase of the fluorescence signal. Theory and construction of the LiSS are presented and experimental results are shown for solutions of single components and simple binary and ternary mixtures. These results show how the lifetime information in the LiSS augments the steady-state intensity information of a standard synchronous spectrum, providing unique information for identification of components and resolution of overlapping spectral peaks. The LiSS technique takes advantage of noise reduction inherent in the extraction of lifetime from PRFS in addition to standard spectral smoothing techniques. The precision of phase determination through PRFS is found to be comparable to that of direct phase measurements at normal fluorescence intensities and superior for low-intensity signals

  13. Portable instrument that integrates irradiation with fluorescence and reflectance spectroscopies during clinical photodynamic therapy of cutaneous disease

    Science.gov (United States)

    Cottrell, W. J.; Oseroff, A. R.; Foster, T. H.

    2006-06-01

    We report a portable clinical instrument for delivering photodynamic therapy (PDT) while performing noninvasive spectroscopic monitoring in vivo. Using an off-surface probe, the instrument delivers the treatment beam to a user-defined field on the skin and performs reflectance and fluorescence spectroscopies at two regions within this field. The instrument is being used to monitor photosensitizer fluorescence photobleaching, fluorescent photoproduct kinetics, blood volume, and hemoglobin oxygen saturation during a pilot clinical trial of 5-aminolevulinic acid-PDT treatment of superficial basal cell carcinoma (BCC). Protoporphyrin IX and photoproduct fluorescence excited by the 633nm PDT treatment laser is collected between 655 and 800nm. During a series of brief treatment interruptions at programable time points, white light reflectance spectra between 475 and 800nm are acquired. Fluorescence spectra are corrected for the effects of absorption and scattering, informed by the reflectance measurements, and then decomposed into known fluorophore contributions in real time using a robust singular value decomposition fitting routine. Reflectance spectra additionally provide information on blood volume and hemoglobin oxygen saturation. Monitoring blood oxygenation and implicit dose metrics such as photosensitizer photobleaching during PDT allows the improved interpretation of clinical results and is helping to guide the treatment protocol for an anticipated low-irradiance PDT clinical trial of BCC.

  14. Remote imaging laser-induced breakdown spectroscopy and laser-induced fluorescence spectroscopy using nanosecond pulses from a mobile lidar system.

    Science.gov (United States)

    Grönlund, Rasmus; Lundqvist, Mats; Svanberg, Sune

    2006-08-01

    A mobile lidar system was used in remote imaging laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF) experiments. Also, computer-controlled remote ablation of a chosen area was demonstrated, relevant to cleaning of cultural heritage items. Nanosecond frequency-tripled Nd:YAG laser pulses at 355 nm were employed in experiments with a stand-off distance of 60 meters using pulse energies of up to 170 mJ. By coaxial transmission and common folding of the transmission and reception optical paths using a large computer-controlled mirror, full elemental imaging capability was achieved on composite targets. Different spectral identification algorithms were compared in producing thematic data based on plasma or fluorescence light.

  15. New insight in the template decomposition process of large zeolite ZSM-5 crystals: an in situ UV-Vis/fluorescence micro-spectroscopy study

    NARCIS (Netherlands)

    Karwacki, L.|info:eu-repo/dai/nl/304824283; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2011-01-01

    A combination of in situ UV-Vis and confocal fluorescence micro-spectroscopy was used to study the template decomposition process in large zeolite ZSM-5 crystals. Correlation of polarized light dependent UV-Vis absorption spectra with confocal fluorescence emission spectra in the 400–750 nm region

  16. Characterizing fluorescent dissolved organic matter in a membrane bioreactor via excitation-emission matrix combined with parallel factor analysis.

    Science.gov (United States)

    Maqbool, Tahir; Quang, Viet Ly; Cho, Jinwoo; Hur, Jin

    2016-06-01

    In this study, we successfully tracked the dynamic changes in different constitutes of bound extracellular polymeric substances (bEPS), soluble microbial products (SMP), and permeate during the operation of bench scale membrane bioreactors (MBRs) via fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC). Three fluorescent groups were identified, including two protein-like (tryptophan-like C1 and tyrosine-like C2) and one microbial humic-like components (C3). In bEPS, protein-like components were consistently more dominant than C3 during the MBR operation, while their relative abundance in SMP depended on aeration intensities. C1 of bEPS exhibited a linear correlation (R(2)=0.738; pbEPS amounts in sludge, and C2 was closely related to the stability of sludge. The protein-like components were more greatly responsible for membrane fouling. Our study suggests that EEM-PARAFAC can be a promising monitoring tool to provide further insight into process evaluation and membrane fouling during MBR operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Paghaleh, Soodeh Jamali; Askari, Hassan Ranjbar; Marashi, Seyed Mohammad Bagher; Rahimi, Mojtaba; Bahrampour, Ali Reza

    2015-01-01

    Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications. - Highlights: • XeCl Excimer laser is employed as an UV source for measurement of AFs in pistachio nuts. • Results are compared with those are measured by the standard HPLC method. • LIFS is an online AFs concentration measurement method for industrial applications

  18. Phosphorus ligand imaging with two-photon fluorescence spectroscopy: towards rational catalyst immobilization

    NARCIS (Netherlands)

    Marras, F.; Kluwer, A.M.; Siekierzycka, J.R.; Vozza, A.; Brouwer, A.M.; Reek, J.N.H.

    2010-01-01

    Spotless catalysts: Ligand immobilization was studied by two-photon fluorescence microscopy with a fluorescent nixantphos ligand as probe (see picture). In the immobilization process ligand aggregates form in solution and are deposited on the support, where they appear as bright spots in

  19. Femtosecond fluorescence upconversion spectroscopy of vapor-deposited tris(8-hydroxyquinoline) aluminum films.

    NARCIS (Netherlands)

    Humbs, W.; Zhang, H.; Glasbeek, M.

    2000-01-01

    Abstract Vapor-deposited Alq3 is used as the green emitting layer in a class of organic light-emitting diodes. In this paper, the time dependence of the fluorescence from thin Alq3 films has been studied by means of the femtosecond fluorescence upconversion technique. From the temporally resolved

  20. Applying fluorescence correlation spectroscopy to investigate peptide-induced membrane disruption

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2017-01-01

    to quantify leakage of fluorescent molecules of different sizes from large unilamellar lipid vesicles, thereby providing a tool for estimating the size of peptide-induced membrane disruptions. If fluorescently labeled lipids are incorporated into the membranes of the vesicles, FCS can also be used to obtain...

  1. Time gated fluorescence lifetime imaging and micro-volume spectroscopy using two-photon excitation

    NARCIS (Netherlands)

    Sytsma, J.; Vroom, J.M.; de Grauw, C.J.; Gerritsen, H.C.

    A scanning microscope utilizing two-photon excitation in combination with fluorescence lifetime contrast is presented. The microscope makes use of a tunable femtosecond titanium:sapphire laser enabling the two-photon excitation of a broad range of fluorescent molecules, including UV probes.

  2. Determination of trace elements in tea by wavelength dispersive X-ray fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gong Chunhui; Zeng Guoqiang; Ge Liangquan; Li Jun; Wen Ziqiang

    2013-01-01

    Background: Measuring trace elements in tea can determine its nutritional value, verify the authenticity and place of origin, and detect the poisonous and harmful elements remaining in tea due to the application of chemical fertilizers and pesticides. Purpose: In order to reduce the time for sample preparation and the costs of equipment maintenance, wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy was used to determine the trace elements in tea which is rapid, non-destructive and accurate. The contents of more than 20 elements can be measured simultaneously. Methods: Sample pieces were made by the sample preparation method of boric acid rebasing. To avoid the exogenous environmental pollution subjected in the growth of tea, we removed the residual dust of the tea by cleaning it. According to the principle that the standard samples should be similar types with the samples to be analyzed to select standard samples. The curves were built by SuperQ, which contained compiling the measurement conditions, establishing the measurement conditions, checking the angles, determining the measurement times, checking PHD and adding the contents and the names of sample pieces. The accuracy of the method can be obtained by comparing the measured values with the trace element contents of standard samples. The contents of trace elements in tea determined by WDXRF can be used to classify the tea attribution and the tea species through cluster analysis of SPSS software. Results: (1) The results show that the biggest relative standard deviation is 0.43% of Pb, and the precision is very good. (2) Five kinds of tea are taken separately in Fujian and Yunnan, measured three times with the established working curves. And tree diagram of cluster analysis can be obtained with SPSS software to analyze the measured average values with cluster analysis, coupling method between groups and Minkowski distance measurement techniques. It can be seen that in the tree diagram, when the

  3. Optical and structural properties of plasma-treated Cordyceps bassiana spores as studied by circular dichroism, absorption, and fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Joon, E-mail: gjlee@kw.ac.kr; Sim, Geon Bo; Choi, Eun Ha [Plasma Bioscience Research Center/Department of Electrical and Biological Physics, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Jun Young; Jang, Siun; Kim, Seong Hwan, E-mail: piceae@naver.com [Department of Microbiology and Institute of Basic Sciences, Dankook University, Cheonan 330-714 (Korea, Republic of)

    2015-01-14

    To understand the killing mechanism of fungal spores by plasma treatment, the optical, structural, and biological properties of the insect pathogenic fungus Cordyceps bassiana spores were studied. A nonthermal atmospheric-pressure plasma jet (APPJ) was used to treat the spores in aqueous solution. Optical emission spectra of the APPJ acquired in air indicated emission peaks corresponding to hydroxyl radicals and atomic oxygen. When the APPJ entered the aqueous solution, additional reactive species were derived from the interaction of plasma radicals with the aqueous solution. Fluorescence and absorption spectroscopy confirmed the generation of hydroxyl radicals and hydrogen peroxide in the plasma-activated water (PAW). Spore counting showed that plasma treatment significantly reduced spore viability. Absorption spectroscopy, circular dichroism (CD) spectroscopy, and agarose gel electrophoresis of the DNA extracted from plasma-treated spores showed a reduction in spore DNA content. The magnitude of the dip in the CD spectrum was lower in the plasma-treated spores than in the control, indicating that plasma treatment causes structural modifications and/or damage to cellular components. Tryptophan fluorescence intensity was lower in the plasma-treated spores than in the control, suggesting that plasma treatment modified cell wall proteins. Changes in spore viability and DNA content were attributed to structural modification of the cell wall by reactive species coming from the APPJ and the PAW. Our results provided evidence that the plasma radicals and the derived reactive species play critical roles in fungal spore inactivation.

  4. Instrumental dead-time and its relationship with matrix corrections in X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Thomas, I.L.; Haukka, M.T.; Anderson, D.H.

    1979-01-01

    The relationship between instrumental dead-time and the self-absorption coefficients, αsub(ii) in x.r.f. matrix correction by means of influence coefficients, is not generally recognized but has important analytical consequences. Systematic errors of the order of 1% (relative) for any analyte result from experimental uncertainties in instrumental dead-time. Such errors are applied unevenly across a given range of concentration because the error depends on the calibration standards and on the instrumental conditions used. Refinement of the instrumental dead-time value and other calibration parameters to conform with influence coefficients determined elsewhere assumes exact knowledge of dead-time of the instrument used originally, and quite similar excitation conditions and spectrometer geometry for the two instruments. Though these qualifications may not be met, adjustment of any of the parameters (dead-time, reference concentration, background concentration, self-absorption and other influence coefficients) can be easily achieved. (Auth.)

  5. Studies on Ternary Complex Formation of U(VI)-salicylate by Using Time-resolved Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Wan Sik; Cho, H. R.; Park, K. K.; Kim, W. H.; Jung, E. C. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Organic ligands containing carboxylic and phenolic functional groups naturally occur in groundwater environment, particularly in forms of polyelectrolytes such as humic and fulvic acids, from microbial degradation of biomass, e.g., plant and animal tissues. These ligands play important roles in dissolution and migration of actinide radionuclide species since they can form stable ternary actinide complexes with common inorganic ions like hydroxides and carbonates. Therefore, model ternary complexes of lanthanides and actinides have been targets of studies to understand their chemical behaviors under near-neutral pH groundwater conditions. Previous model carboxylic ligands include phthalates, maleic acids, or alpha- substituted carboxylic acids. However, majority of previous studies investigated binary systems or used potentiometric titration method that requires high ligand concentration in mM levels. Recently, highly sensitive time-resolved laserinduced fluorescence spectroscopy (TRLFS) has been used to investigate lower concentration (e.g., a few {mu}M levels) reactions of binary complexes between of ligands and metal ions. This technique provides information regarding electronic structures and complexation constants as well as fluorescence quenching mechanism. In the present study, we studied the U(VI)-OH-salicylate (SA) ternary complex formation at higher pH (> 4) via TRLF spectrum and UV-Vis absorbance measurement. Preliminary studies show that the fluorescence (FL) intensity of hydroxouranyl species at pH 4.5 decreases as SA concentration elevates in aqueous solution. Fluorescence quenching mechanism by SA is suggested based on FL intensity (I) and lifetime (tau) measurement via TRLFS

  6. Fluorescence Spectroscopy Approaches for the Development of a Real-Time Organophosphate Detection System Using an Enzymatic Sensor

    Directory of Open Access Journals (Sweden)

    Paola Carullo

    2015-02-01

    Full Text Available Organophosphates are organic substances that contain a phosphoryl or a thiophosphoryl bond. They are mainly used around the world as pesticides, but can also be used as chemical warfare agents. Their detection is normally entrusted to techniques like GC- and LC-MS that, although sensitive, do not allow their identification on site and in real time. We have approached their identification by exploiting the high-affinity binding of these compounds with the esterase 2 from Alicyclobacillus acidocaldarius. Using an in silico analysis to evaluate the binding affinities of the enzyme with organophosphate inhibitors, like paraoxon, and other organophosphate compounds, like parathion, chlorpyriphos, and other organophosphate thio-derivatives, we have designed fluorescence spectroscopy experiments to study the quenching of the tryptophan residues after esterase 2 binding with the organophosphate pesticides. The changes in the fluorescence signals permitted an immediate and quantitative identification of these compounds from nano- to picomolar concentrations. A fluorescence based polarity-sensitive probe (ANS was also employed as a means to understand the extent of the interactions involved, as well as to explore other ways to detect organophosphate pesticides. Finally, we designed a framework for the development of a biosensor that exploits fluorescence technology in combination with a sensitive and very stable bio-receptor.

  7. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-10-15

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds.

  8. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M.

    2014-01-01

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds

  9. Design and development of high-resolution atomic beam fluorescence spectroscopy facility for isotope shift and hyperfine structure measurements

    International Nuclear Information System (INIS)

    Acharyulu, G.V.S.G.; Sankari, M.; Kiran Kumar, P.V.; Suryanarayana, M.V.

    2012-01-01

    A high-resolution atomic beam fluorescence spectroscopy facility for the determination of isotope shifts and hyperfine structure in atomic species has been designed and developed. A resistively heated graphite tube atomic beam source was designed, tested and integrated into a compact interaction chamber for atomic beam fluorescence experiments. The design of the laser-atom interaction chamber and the source has been modified in a phased manner so as to achieve sub-Doppler resolution. The system has been used to record the hyperfine spectrum of the D2 transitions of Rb and K isotopes. The spectral resolution achieved is ∼ 26 MHz and is adequate to carry out high resolution measurement of isotope shifts and hyperfine structure of various atomic species. The other major advantage of the source is that it requires very small amounts of sample for achieving very good signal to noise ratio. (author)

  10. Assessment of the Inhibitory Effect of Rifampicin on Amyloid Formation of Hen Egg White Lysozyme: Thioflavin T Fluorescence Assay versus FTIR Difference Spectroscopy

    Directory of Open Access Journals (Sweden)

    Gang Ma

    2014-01-01

    Full Text Available The inhibitory effect of rifampicin on the amyloid formation of hen egg white lysozyme was assessed with both Thioflavin T (ThT fluorescence assay and Fourier transform infrared (FTIR difference spectroscopy. We reveal that ThT fluorescence assay gives a false positive result due to rifampicin interference, while FTIR difference spectroscopy provides a reliable assessment. With FTIR, we show that rifampicin only has marginally inhibitory effect. We then propose that FTIR difference spectroscopy can potentially be a convenient method for inhibitor screening in amyloid study.

  11. Electron Shuttling by Dissolved Humic Substances: Using Fluorescence Spectroscopy to Move Beyond the Laboratory to Natural Lakes, Streams and Groundwaters

    Science.gov (United States)

    McKnight, D. M.

    2017-12-01

    Humic substances are an important class of reactive chemical species in natural waters, and one important role is their capacity to as an electron acceptor and/or electron shuttle to ferric iron present as solid phase ferric oxides. Several lines of evidence point to quinone-like moieties being the main redox active moieties that can be used by microbes in respiration. Concomitantly, the humic fraction of dissolved organic mater (DOM) contains the dominant fluorophores in many natural waters. Examination of excitation emission matrices (EEMs) across redox gradients in diverse aquatic systems show that the EEMs are generally red-shifted under reducing conditions, such as anoxic bottom waters in lakes and hypoxic waters in riparian wetlands. Furthermore, there is striking similarity between the humic fluorophores that are resolved by statistical analysis and the fluorescence spectra of model quinone compounds, with the more reduced species having red-shifted fluorescence spectra. This apparent red-shift can be quantified based on the distribution of apparently "quinone-like", "semi-quinone-like" and "hydroquinone-like" fluorophores determined by the PARAFAC statistical analysis. Because fluorescence spectroscopy can be applied at ambient DOM concentrations for samples that have been maintained in an anoxic condition, fluorescence spectroscopy can provide insight into the role of humic electron shuttling in natural systems. Examples are presented demosntrating the changing EEMs in anoxic bottomwaters in a lake in the McMurdo Dry Valleys following a major flood event and the role of organic material in the mobilization of arsenic in shallow groundwater in South East Asia.

  12. Time-resolved and steady-state studies of biologically and chemically relevant systems using laser, absorption, and fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Charles Ashley [Iowa State Univ., Ames, IA (United States)

    2014-12-20

    In Chapter 2 several experimental and data analysis methods used in this thesis are described. In Chapter 3 steady-state fluorescence spectroscopy was used to determine the concentration of the efflux pump inhibitors (EPIs), pheophorbide a and pyropheophorbide a, in the feces of animals and it was found that their levels far exceed those reported to be inhibitory to efflux pumps. In Chapter 4 the solvation dynamics of 6-Propionyl-2-(N,Ndimethyl) aminonaphthalene (PRODAN) was studied in reverse micelles. The two fluorescent states of PRODAN solvate on different time scales and as such care must be exercised in solvation dynamic studies involving it and its analogs. In Chapter 5 we studied the experimental and theoretical solvation dynamics of coumarin 153 (C153) in wild-type (WT) and modified myoglobins. Based on the nuclear magnetic resonance (NMR) spectroscopy and time-resolved fluorescence studies, we have concluded that it is important to thoroughly characterize the structure of a protein and probe system before comparing the theoretical and experimental results. In Chapter 6 the photophysical and spectral properties of a derivative of the medically relevant compound curcumin called cyclocurcumin was studied. Based on NMR, fluorescence, and absorption studies, the ground- and excited-states of cyclocurcumin are complicated by the existence of multiple structural isomers. In Chapter 7 the hydrolysis of cellulose by a pure form of cellulase in an ionic liquid, HEMA, and its aqueous mixtures at various temperatures were studied with the goal of increasing the cellulose to glucose conversion for biofuel production. It was found that HEMA imparts an additional stability to cellulase and can allow for faster conversion of cellulose to glucose using a pre-treatment step in comparison to only buffer.

  13. Drivers of fluorescent dissolved organic matter in the global epipelagic ocean

    KAUST Repository

    Catalá , T. S.; Á lvarez-Salgado, X. A.; Otero, J.; Iuculano, F.; Companys, B.; Horstkotte, B.; Romera-Castillo, C.; Nieto-Cid, M.; Latasa, M.; Moran, Xose Anxelu G.; Gasol, J. M.; Marrasé , C.; Stedmon, C. A.; Reche, I.

    2016-01-01

    Fluorescent dissolved organic matter (FDOM) in open surface waters (< 200 m) of the Atlantic, Pacific, and Indian oceans was analysed by excitation-emission matrix (EEM) spectroscopy and parallel factor analysis (PARAFAC). A four-component PARAFAC

  14. Matrix effect on emission/current correlated analysis in laser-induced breakdown spectroscopy of liquid droplets

    International Nuclear Information System (INIS)

    Huang, J.-S.; Ke, C.-B.; Lin, K.-C.

    2004-01-01

    We have investigated influence of matrix salts on the liquid droplets by laser-induced breakdown spectroscopy (LIBS). An electrospray ionization technique coupled with LIBS is employed to generate the microdroplets of the Na sample solution with various matrix salts added. A sequence of single-shot time-resolved LIB emission signals is detected. The LIB signal intensity integrated within a gate linearly correlates with the plasma-induced current response obtained simultaneously on a single-shot basis. The slopes thus obtained increase with the sample concentration, but appear to be irrespective of different matrix salts, added up to a 2000 mg/l concentration. The matrix salts involved have the same K + cation but different anions. Given a laser radiation emitting at 355 nm with the energy fixed at 23±1 mJ, a limit of detection (LOD) of 1.0 mg/l may be achieved for the Na analysis. The current normalization might have probably taken into account the ablated amount of the sample and the plasma temperature. Accordingly, the LIB/current correlated analysis becomes efficient to suppress the signal fluctuation, improve the LOD determination, and concurrently correct the matrix effect

  15. Fluorescence spectroscopy studies of HEK293 cells expressing DOR-Gi1alfa fusion protein; the effect of cholesterol depletion

    Czech Academy of Sciences Publication Activity Database

    Brejchová, Jana; Sýkora, Jan; Dlouhá, Kateřina; Roubalová, Lenka; Ostašov, Pavel; Vošahlíková, Miroslava; Hof, Martin; Svoboda, Petr

    2011-01-01

    Roč. 1808, č. 12 (2011), s. 2819-2829 ISSN 0005-2736 R&D Projects: GA MŠk(CZ) LC06063; GA MŠk(CZ) LC554; GA ČR(CZ) GD305/08/H037 Grant - others:GA ČR(CZ) GAP208/10/1090 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40400503 Keywords : plasma membrane * cholesterol depletion * fluorescence spectroscopy * hydrophobic membrane interior * delta-opioid receptor ( DOR ), * G protein Subject RIV: BO - Biophysics Impact factor: 3.990, year: 2011

  16. A laser-spectroscopy complex for fluorescent diagnostics and photodynamic therapy of age-related macula degeneration

    Science.gov (United States)

    Shevchik, S. A.; Meerovich, Gennadii A.; Budzinskaya, M. V.; Ermakova, N. A.; Kharnas, Sergey S.; Loschenov, Victor B.

    2004-06-01

    A laser-spectroscopy complex was developed for fluorescent diagnostics and photodynamic therapy of age related macula degeneration using the Russian photosensitizer Photosense. The complex is based on slit lamp which was additionally equipped with an optical adapter, and the video adapter allows to combine the procedure of photodynamic therapy and the control of its carrying in the frame work of one procedure. The sensitivity and spatial resolution of the complex were investigated using a special test object. The availability of the developed complex and Photosense itself was examined on experimental animals.

  17. Application of laser fluorescence spectroscopy by two-photon excitation into atomic hydrogen density measurement in reactive plasmas

    International Nuclear Information System (INIS)

    Kajiwara, Toshinori; Takeda, Kazuyuki; Kim, Hee Je; Park, Won Zoo; Muraoka, Katsunori; Akazaki, Masanori; Okada, Tatsuo; Maeda, Mitsuo.

    1990-01-01

    Density profiles of hydrogen atoms in reactive plasmas of hydrogen and methane gases were measured, for the first time, using the laser fluorescence spectroscopy by two-photon excitation of Lyman beta transition and observation at the Balmer alpha radiation. Absolute density determinations showed atomic densities of around 3 x 10 17 m -3 , or the degree of dissociation to be 10 -4 . Densities along the axis perpendicular to the RF electrode showed peaked profiles, which were due to the balance of atomic hydrogen production by electron impact on molecules against diffusion loss to the walls. (author)

  18. Study of the spectroscopy properties of uranium matrix doped with europium. Energy transfer between UO22+ and Eu3+

    International Nuclear Information System (INIS)

    Luiz, Jose Eduardo Monteiro de Sa

    2007-01-01

    Uranyl compounds (UO 2 2+ ) present a great potential as luminescent materials, for instance, applied in technology laser, luminescent probes, cells for conversion of energy, etc. In this work it is studied the efficiency of energy transfer in the compound Eu 3+ doped in UO 2 (MS) 2 .(H 2 O)n matrix and UO 2 2+ in Eu(MS) 3 (H 2 O)n for to be used as efficient Light Conversion Molecular Devices (LCMD) and/or in solar cells for energy conversion. It is also described the synthesis, characterization and spectroscopic study of the matrix Eu(MS) 3 .(H 2 O)n.(x%mol) UO 2 2+ and UO 2 (MS) 2 .(H 2 O)n.(x%mol) Eu 3+ (where x= 1, 3, 5 and 10). The compounds obtained was characterized by elementary analyses for determine the U 6+ concentration, infrared spectra, thermal analyses and luminescence spectra. The IR data suggest that the MS ligand acts as bidentate one. The emission spectra of Eu 3+ doped in UO 2 (MS) 2 .(H 2 O) 2 matrix showed characteristic fluorescence bands of the uranyl ion, attributed to the transition of 3 Π u -> 1 Σ g + of the uranium matrix. For the UO 2 2+ in Eu(MS) 3 (H 2 O) 6 the transitions of D o -> 7 F J (J=0 ->4 ) are predominant in the spectra. The intense europium luminescence associated with uranyl sensitising is registered in emission spectra of Eu 3+ ions in the range of 420-720 nm. The quenching rate constant of UO 2 2+ fluorescence with Eu 3+ is also determined. (author)

  19. Fluorescent Labeling of Collagen Production by Cells for Noninvasive Imaging of Extracellular Matrix Deposition.

    Science.gov (United States)

    Bardsley, Katie; Yang, Ying; El Haj, Alicia J

    2017-04-01

    Extracellular matrix (ECM) is an essential component of tissues and provides both integrity and biological cues for cells. Collagen is one of the major proteins found within the ECM and therefore is an essential component of all engineered tissues. Therefore, in this article, we present a method for the online real-time monitoring of collagen deposition in three-dimensional engineered constructs. This method revolves around modification of collagen through the addition of azide-L-proline to cell culture media. The incorporation of azide-L-proline into the neocollagen produced by cells can then be detected by reaction with 10 mM of a Click-IT Alexa Fluor 488 DIBO Alkyne. The reaction was shown as being specific to the collagen as little background staining was observed in cultures, which did not contain the modified proline, and the staining was also depleted after treatment with collagenase and colocalization of collagen type I staining by immunochemistry assay. Real-time online staining of collagen deposition was observed under different culture conditions without affecting proliferation. Collagen deposition was observed to be increased under mechanical stimulation; however, the localization varied across stimulation regimes. This is a new technique for real-time monitoring of cell-produced collagen and will be a valuable addition to the tissue engineering field.

  20. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield.

    Science.gov (United States)

    Tizei, Luiz H G; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield

    International Nuclear Information System (INIS)

    Tizei, Luiz H.G.; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission.

  2. On-line analysis of algae in water by discrete three-dimensional fluorescence spectroscopy.

    Science.gov (United States)

    Zhao, Nanjing; Zhang, Xiaoling; Yin, Gaofang; Yang, Ruifang; Hu, Li; Chen, Shuang; Liu, Jianguo; Liu, Wenqing

    2018-03-19

    In view of the problem of the on-line measurement of algae classification, a method of algae classification and concentration determination based on the discrete three-dimensional fluorescence spectra was studied in this work. The discrete three-dimensional fluorescence spectra of twelve common species of algae belonging to five categories were analyzed, the discrete three-dimensional standard spectra of five categories were built, and the recognition, classification and concentration prediction of algae categories were realized by the discrete three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that similarities between discrete three-dimensional standard spectra of different categories were reduced and the accuracies of recognition, classification and concentration prediction of the algae categories were significantly improved. By comparing with that of the chlorophyll a fluorescence excitation spectra method, the recognition accuracy rate in pure samples by discrete three-dimensional fluorescence spectra is improved 1.38%, and the recovery rate and classification accuracy in pure diatom samples 34.1% and 46.8%, respectively; the recognition accuracy rate of mixed samples by discrete-three dimensional fluorescence spectra is enhanced by 26.1%, the recovery rate of mixed samples with Chlorophyta 37.8%, and the classification accuracy of mixed samples with diatoms 54.6%.

  3. Spatially resolved analyses of uranium species using a coupled system made up of confocal laser-scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS)

    International Nuclear Information System (INIS)

    Brockmann, S.; Grossmann, K.; Arnold, T.

    2014-01-01

    The fluorescent properties of uranium when excited by UV light are used increasingly for spectroscope analyses of uranium species within watery samples. Here, alongside the fluorescent properties of the hexavalent oxidation phases, the tetra and pentavalent oxidation phases also play an increasingly important role. The detection of fluorescent emission spectrums on solid and biological samples using (time-resolved) laser induced fluorescence spectroscopy (TRLFS or LIFS respectively) has, however, the disadvantage that no statements regarding the spatial localisation of the uranium can be made. However, particularly in complex, biological samples, such statements on the localisation of the uranium enrichment in the sample are desired, in order to e.g. be able to distinguish between intra and extra-cellular uranium bonds. The fluorescent properties of uranium (VI) compounds and minerals can also be used to detect their localisation within complex samples. So the application of fluorescent microscopic methods represents one possibility to localise and visualise uranium precipitates and enrichments in biological samples, such as biofilms or cells. The confocal laser-scanning microscopy (CLSM) is especially well suited to this purpose. Coupling confocal laser-scanning microscopy (CLSM) with laser induced fluorescence spectroscopy (LIFS) makes it possible to localise and visualise fluorescent signals spatially and three-dimensionally, while at the same time being able to detect spatially resolved, fluorescent-spectroscopic data. This technology is characterised by relatively low detection limits from up to 1.10 -6 M for uranium (VI) compounds within the confocal volume. (orig.)

  4. CHARACTERIZATION OF SOIL HUMIC SUBSTANCES BY ULTRAVIOLET-VISIBLE AND SYNCHRONOUS FLUORESCENCE SPECTROSCOPY

    Directory of Open Access Journals (Sweden)

    NADĚŽDA FASUROVÁ

    2011-01-01

    Full Text Available We focused our study on ultraviolet-visible and synchronous fluorescence spectra and indexes of humic subctances isolated from five Czech soil samples: Haplic Chernozem, Luvic Chernozem, Gleyic Luvisol, Haplic Cambisol and Leptic Cambisol. Results indicated the following HS quality: Haplic Chernozem > Luvic Chernozem > Gleyic Luvisol > Haplic Cambisol > Leptic Cambisol. Humic acids and fulvic acids ratios (HA/FA were increasing together with decreasing values of Q4/6 measured in visible spectral range. Highest absorbance in visible spectral range was detected in Haplic Chernozem and Luvic Chernozem. Maximum relative fluorescence was found in Haplic Chernozem. SFS spectra (in emission mode at Δλ=20 nm showed five main fluorophore peaks at: 360, 470, 488, 502 and 512 nm. Fluorescence behaviour of studied samples was compared with Elliot soil humic acid standard (IHSS. Correlation between fluorescence indexes (F and humification degree (HD R2= 0.88 and between calculated humification degree (HD* and humic acids content (HA sum R2=0.84 and between fluorescence indexes F and HA/FA ratios (R2=0.88 were found.

  5. Quantification of Coffea arabica and Coffea canephora var. robusta concentration in blends by means of synchronous fluorescence and UV-Vis spectroscopies.

    Science.gov (United States)

    Dankowska, A; Domagała, A; Kowalewski, W

    2017-09-01

    The potential of fluorescence, UV-Vis spectroscopies as well as the low- and mid-level data fusion of both spectroscopies for the quantification of concentrations of roasted Coffea arabica and Coffea canephora var. robusta in coffee blends was investigated. Principal component analysis was used to reduce data multidimensionality. To calculate the level of undeclared addition, multiple linear regression (PCA-MLR) models were used with lowest root mean square error of calibration (RMSEC) of 3.6% and root mean square error of cross-validation (RMSECV) of 7.9%. LDA analysis was applied to fluorescence intensities and UV spectra of Coffea arabica, canephora samples, and their mixtures in order to examine classification ability. The best performance of PCA-LDA analysis was observed for data fusion of UV and fluorescence intensity measurements at wavelength interval of 60nm. LDA showed that data fusion can achieve over 96% of correct classifications (sensitivity) in the test set and 100% of correct classifications in the training set, with low-level data fusion. The corresponding results for individual spectroscopies ranged from 90% (UV-Vis spectroscopy) to 77% (synchronous fluorescence) in the test set, and from 93% to 97% in the training set. The results demonstrate that fluorescence, UV, and visible spectroscopies complement each other, giving a complementary effect for the quantification of roasted Coffea arabica and Coffea canephora var. robusta concentration in blends. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Study of the relaxation dynamics of Styryl 8 and of its solvent cage by sub-pico-second fluorescence laser spectroscopy

    International Nuclear Information System (INIS)

    Hebert, Philippe

    1992-01-01

    This research thesis addressed the study of the solvation dynamics of the fluorescent excited state of the styryl 8 molecule, and also the study of the photo-physical and photo-chemical properties, solvatochromism, fluorescence quantum efficiencies, non-radiative de-activation process, and photo-stability of this molecule. The development of a time-resolved (at a pico-second scale) fluorescence laser spectroscopy in a non linear crystal allowed the observation of styryl 8 short time fluorescence kinetics in different solvents, and the analysis of the evolution in time of its fluorescence spectra. Styryl rotation movements have also been studied with the same apparatus by performing time-resolved fluorescence anisotropy. The comparison between experimental results and those obtained with theoretical models highlights interactions between solute and solvent [fr

  7. New insights into heat induced structural changes of pectin methylesterase on fluorescence spectroscopy and molecular modeling basis

    Science.gov (United States)

    Nistor, Oana Viorela; Stănciuc, Nicoleta; Aprodu, Iuliana; Botez, Elisabeta

    2014-07-01

    Heat-induced structural changes of Aspergillus oryzae pectin methylesterase (PME) were studied by means of fluorescence spectroscopy and molecular modeling, whereas the functional enzyme stability was monitored by inactivation studies. The fluorescence spectroscopy experiments were performed at two pH value (4.5 and 7.0). At both pH values, the phase diagrams were linear, indicating the presence of two molecular species induced by thermal treatment. A red shift of 7 nm was observed at neutral pH by increasing temperature up to 60 °C, followed by a blue shift of 4 nm at 70 °C, suggesting significant conformational rearrangements. The quenching experiments using acrylamide and iodide demonstrate a more flexible conformation of enzyme with increasing temperature, especially at neutral pH. The experimental results were complemented with atomic level observations on PME model behavior after performing molecular dynamics simulations at different temperatures. The inactivation kinetics of PME in buffer solutions was fitted using a first-order kinetics model, resulting in activation energy of 241.4 ± 7.51 kJ mol-1.

  8. Influence of Conducting Polymer as Filler and Matrix on the Spectral, Morphological and Fluorescent Properties of Sonochemically Intercalated poly(o-phenylenediamine)/Montmorillonite Nanocomposites.

    Science.gov (United States)

    Riaz, Ufana; Ashraf, Syed M; Verma, Anurakshee

    2016-01-01

    Nanocomposites consisting of spatially confined polymeric chains are of great interest due to their application in optoelectronic and photonics devices. Polymer layered silicate nanocomposites have attracted much attention in industry as well as academia owing to their remarkable physical and chemical properties as compared to conventional polymer nanocomposites. In present study, comparative investigation of the in-situ polymerization of poly(ophenylenediamine) intercalated montmorillonite has been done via two methods i.e using poly(o-phenylenediamine) as filler for MMT in one case and as matrix in the other. Intercalation and in-situ polymerization was confirmed by FT-IR, UV-Visible spectroscopy and XRD studies. TEM and optical microscopy studies confirmed the self-assembled morphology of nanocomposites while the fluorescence properties revealed that controlled emission could be achieved by confining poly(o-phenylenediamine) in MMT galleries. Intercalation and in-situ polymerization of o-phenylenediamine within MMT was successfully carried out using sonochemical technique. The growth of conducting polymers in the interlayer region of the clays has been shown to dramatically improve the properties of conducting polymers. Also, the loading of the polymer in the MMT has shown to influence the optical properties of the nanocomposite. IR spectra and XRD analysis confirmed the intercalation of POPD and its polymerization within the clay galleries. UV spectra revealed the doped state of POPD within clay galleries. Highest oscillator strength of 0.0137 was observed for POPD:MMT-1:0.25. Spherical self-assembled morphology was attained for POPD:MMT-1:0.25. XRD revealed major shift of 82.5 Å for the nanocomposite POPD:MMT-1:1, POPD:MMT-1:0.5 and MMT:POPD-1:0.25. Blue shift of 20 nm was noticed in the fluorescence spectra of POPD:MMT-1:0.25 and POPD:MMT-1:0.5 which was correlated to the intense interaction between NH of POPD with SiO of MMT. Highest quantum yield of 0

  9. Non-matrix corrected organic sulfur determination by energy dispersive X-ray spectroscopy for western Kentucky coals and residues

    International Nuclear Information System (INIS)

    Clark, C.P.; Freeman, G.B.; Hower, J.C.

    1984-01-01

    A method for non-matrix corrected organic sulfur analysis by energy dispersive X-ray spectroscopy has been developed using petroleum coke standards. Typically, electron beam microanalysis is a rapid, nondestructive analytical technique to quantitatively measure organic sulfur in coal. The results show good correlation to ASTM values for numerous well characterized coals with a wide range in total and pyritic sulfur content. This direct analysis is capable of reducing error commonly associated with the present ASTM method which relies on an indirect measure of organic sulfur by difference. The precision of the organic sulfur values determined in the present study is comparable to that obtained by ZAF matrix corrected microanalysis. The energy dispersive microanalysis is capable of measuring micro as well as bulk organic sulfur levels

  10. In situ fluorescence spectroscopy correlates ionomer degradation to reactive oxygen species generation in an operating fuel cell.

    Science.gov (United States)

    Prabhakaran, Venkateshkumar; Arges, Christopher G; Ramani, Vijay

    2013-11-21

    The rate of generation of reactive oxygen species (ROS) within the polymer electrolyte membrane (PEM) of an operating proton exchange member fuel cell (PEMFC) was monitored using in situ fluorescence spectroscopy. A modified barrier layer was introduced between the PEM and the electrocatalyst layer to eliminate metal-dye interactions and fluorescence resonance energy transfer (FRET) effects during measurements. Standard fuel cell operating parameters (temperature, relative humidity, and electrode potential) were systematically varied to evaluate their influence on the rate of ROS generation during PEMFC operation. Independently, the macroscopic rate of PEM degradation was measured by monitoring the fluoride ion emission rate (FER) in the effluent stream at each operating condition. The ROS generation reaction rate constant (estimated from the in situ fluorescence experiments) correlated perfectly with the measured FER across all conditions, demonstrating unequivocally for the first time that a direct correlation exists between in situ ROS generation and PEM macroscopic degradation. The activation energy for ROS generation within the PEM was estimated to be 12.5 kJ mol(-1).

  11. Method of using a nuclear magnetic resonance spectroscopy standard. [SO/sub 2/ in gases by fluorescence

    Science.gov (United States)

    Spicer, L.D.; Bennett, D.W.; Davis, J.F.

    1983-05-09

    (CH/sub 3/)/sub 3/SiNSO is produced by the reaction of ((CH/sub 3/)/sub 3/SI)/sub 2/NH with SO/sub 2/. Also produced in the reaction are ((CH/sub 3/)/sub 3/Si)/sub 2/O and a new solid compound (NH/sub 4/)((CH/sub 3/)/sub 3/SiOSO/sub 2/). Both (CH/sub 3/)/sub 3/SiNSO and (NH/sub 4/)((CH/sub 3/)/sub 3/SiOSO/sub 2/) have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO/sub 2/ pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH/sub 3/)/sub 3/Si)/sub 2/NH, whereby any SO/sub 2/ present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO/sub 2/ in the original gas sample. The solid product (NH/sub 4/)((CH/sub 3/)/sub 3/SiOSO/sub 2/) may be used as a standard in solid state NMR spectroscopy, wherein the resonance peaks of either /sup 1/H, /sup 13/C, /sup 15/N, or /sup 29/Si may be used as a reference.

  12. Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms.

    Science.gov (United States)

    Woltmann, Eva; Meyer, Hans; Weigel, Diana; Pritzke, Heinz; Posch, Tjorben N; Kler, Pablo A; Schürmann, Klaus; Roscher, Jörg; Huhn, Carolin

    2014-10-01

    High production output of solid pharmaceutical formulations requires fast methods to ensure their quality. Likewise, fast analytical procedures are required in forensic sciences, for example at customs, to substantiate an initial suspicion. We here present the design and the optimization of an instrumental setup for rapid and non-invasive characterization of tablets by laser-induced fluorescence spectroscopy (with a UV-laser (λ ex = 266 nm) as excitation source) in reflection geometry. The setup was first validated with regard to repeatability, bleaching phenomena, and sensitivity. The effect on the spectra by the physical and chemical properties of the samples, e.g. their hardness, homogeneity, chemical composition, and granule grain size of the uncompressed material, using a series of tablets, manufactured in accordance with design of experiments, was investigated. Investigation of tablets with regard to homogeneity, especially, is extremely important in pharmaceutical production processes. We demonstrate that multiplicative scatter correction is an appropriate tool for data preprocessing of fluorescence spectra. Tablets with different physical and chemical characteristics can be discriminated well from their fluorescence spectra by subjecting the results to principal component analysis.

  13. Fluorescence Correlation Spectroscopy to find the critical balance between extracellular association and intracellular dissociation of mRNA-complexes.

    Science.gov (United States)

    Zhang, Heyang; De Smedt, Stefaan C; Remaut, Katrien

    2018-05-10

    Fluorescence Correlation Spectroscopy (FCS) is a promising tool to study interactions on a single molecule level. The diffusion of fluorescent molecules in and out of the excitation volume of a confocal microscope leads to the fluorescence fluctuations that give information on the average number of fluorescent molecules present in the excitation volume and their diffusion coefficients. In this context, we complexed mRNA into lipoplexes and polyplexes and explored the association/dissociation degree of complexes by using gel electrophoresis and FCS. FCS enabled us to measure the association and dissociation degree of mRNA-based complexes both in buffer and protein-rich biological fluids such as human serum and ascitic fluid, which is a clear advantage over gel electrophoresis that was only applicable in protein-free buffer solutions. Furthermore, following the complex stability in buffer and biological fluids by FCS assisted to understand how complex characteristics, such as charge ratio and strength of mRNA binding, correlated to the transfection efficiency. We found that linear polyethyleneimine prevented efficient translation of mRNA, most likely due to a too strong mRNA binding, whereas the lipid based carrier Lipofectamine ® messengerMAX did succeed in efficient release and subsequent translation of mRNA in the cytoplasm of the cells. Overall, FCS is a reliable tool for the in depth characterization of mRNA complexes and can help us to find the critical balance keeping mRNA bound in complexes in the extracellular environment and efficient intracellular mRNA release leading to protein production. The delivery of messenger RNA (mRNA) to cells is promising to treat a variety of diseases. Therefore, the mRNA is typically packed in small lipid particles or polymer particles that help the mRNA to reach the cytoplasm of the cells. These particles should bind and carry the mRNA in the extracellular environment (e.g. blood, peritoneal fluid, ...), but should release

  14. Conformational study of sarcosine as probed by matrix-isolation FT-IR spectroscopy and molecular orbital calculations

    OpenAIRE

    Gómez-Zavaglia, Andrea; Fausto, R.

    2003-01-01

    Sarcosine (N-methylglycine) has been studied by matrix-isolation FT-IR spectroscopy and molecular orbital calculations undertaken at the DFT/B3LYP and MP2 levels of theory with the 6-311++G(d, p) and 6-31++G(d, p) basis set, respectively. Eleven different conformers were located in the potential energy surface (PES) of sarcosine, with the ASC conformer being the ground conformational state. This form is analogous to the glycine most stable conformer and is characterized by a NH...O= intramole...

  15. EPR and Fluorescence Spectroscopy in the Photodegradation Study of Arabian and Colombian Crude Oils

    Directory of Open Access Journals (Sweden)

    Carmen L. B. Guedes

    2006-01-01

    W/m2. The reduction in the linewidth of the free radical of 9.8% in Arabian oil and 18.5% in Colombian oil, as well as the decrease in radical numbers, indicated photochemical degradation, especially in Colombian oil. The linewidth narrowing corresponding to free radicals in the irradiated oils occurred due to the rearrangement among radicals and aromatic carbon consumption. The irradiated oils showed a reduction in the relative intensity of fluorescence of the aromatics with high molecular mass, polar aromatics, and asphaltene. The fluorescent fraction was reduced by 61% in Arabian oil and 72% in Colombian oil, corresponding to photochemical degradation of crude oil aromatic compounds.

  16. Determination of Nb in ZrO2 matrix using Wavelength Dispersive X-Ray Fluorescence (WDXRF) technique

    International Nuclear Information System (INIS)

    Jha, S.N.; Kapoor, S.K.; Malhotra, S.K.; Kaimal, R.; Kamat, M.J.; Sehra, J.C.

    1998-09-01

    A Wavelength Dispersive X-Ray Fluorescence (WDXRF) method is described for the estimation of niobium in ZrO 2 matrix in the concentration range of 0.5 to 35%. Analysis of Nb is desired during the reclamation of zirconium from Zr-2.5% Nb scrap. Zr-2.5% Nb is used in water cooled nuclear power reactors on account of high creep resistance and strength. For the reclamation of these metals from the scrap, chlorination is done to produce mixed chloride. The mixed chloride is treated to obtain individual chloride for eventually converting to respective metal. Analysis is required to ascertain purity of these metals reclaimed from the scrap. Primary x-rays from gold target x-ray tube were used to excite the K lines of Nb. A linear relation has been found between the intensity of Nb-Kα 1,2 line and concentration in the above range and the detection limit was 0.03% for 10 seconds counting time. (author)

  17. Detection and differentiation of bacterial spores in a mineral matrix by Fourier transform infrared spectroscopy (FTIR and chemometrical data treatment

    Directory of Open Access Journals (Sweden)

    Brandes Ammann Andrea

    2011-07-01

    Full Text Available Abstract Background Fourier transform infrared spectroscopy (FTIR has been used as analytical tool in chemistry for many years. In addition, FTIR can also be applied as a rapid and non-invasive method to detect and identify microorganisms. The specific and fingerprint-like spectra allow - under optimal conditions - discrimination down to the species level. The aim of this study was to develop a fast and reproducible non-molecular method to differentiate pure samples of Bacillus spores originating from different species as well as to identify spores in a simple matrix, such as the clay mineral, bentonite. Results We investigated spores from pure cultures of seven different Bacillus species by FTIR in reflection or transmission mode followed by chemometrical data treatment. All species investigated (B. atrophaeus, B. brevis, B. circulans, B. lentus, B. megaterium, B. subtilis, B. thuringiensis are typical aerobic soil-borne spore formers. Additionally, a solid matrix (bentonite and mixtures of benonite with spores of B. megaterium at various wt/wt ratios were included in the study. Both hierarchical cluster analysis and principal component analysis of the spectra along with multidimensional scaling allowed the discrimination of different species and spore-matrix-mixtures. Conclusions Our results show that FTIR spectroscopy is a fast method for species-level discrimination of Bacillus spores. Spores were still detectable in the presence of the clay mineral bentonite. Even a tenfold excess of bentonite (corresponding to 2.1 × 1010 colony forming units per gram of mineral matrix still resulted in an unambiguous identification of B. megaterium spores.

  18. Simultaneous membrane interaction of amphipathic peptide monomers, self-aggregates and cargo complexes detected by fluorescence correlation spectroscopy.

    Science.gov (United States)

    Vasconcelos, Luís; Lehto, Tõnis; Madani, Fatemeh; Radoi, Vlad; Hällbrink, Mattias; Vukojević, Vladana; Langel, Ülo

    2018-02-01

    Peptides able to translocate cell membranes while carrying macromolecular cargo, as cell-penetrating peptides (CPPs), can contribute to the field of drug delivery by enabling the transport of otherwise membrane impermeable molecules. Formation of non-covalent complexes between amphipathic peptides and oligonucleotides is driven by electrostatic and hydrophobic interactions. Here we investigate and quantify the coexistence of distinct molecular species in multiple equilibria, namely peptide monomer, peptide self-aggregates and peptide/oligonucleotide complexes. As a model for the complexes, we used a stearylated peptide from the PepFect family, PF14 and siRNA. PF14 has a cationic part and a lipid part, resembling some characteristics of cationic lipids. Fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) were used to detect distinct molecular entities in solution and at the plasma membrane of live cells. For that, we labeled the peptide with carboxyrhodamine 6G and the siRNA with Cyanine 5. We were able to detect fluorescent entities with diffusional properties characteristic of the peptide monomer as well as of peptide aggregates and peptide/oligonucleotide complexes. Strategies to avoid peptide adsorption to solid surfaces and self-aggregation were developed and allowed successful FCS measurements in solution and at the plasma membrane. The ratio between the detected molecular species was found to vary with pH, peptide concentration and the proximity to the plasma membrane. The present results suggest that the diverse cellular uptake mechanisms, often reported for amphipathic CPPs, might result from the synergistic effect of peptide monomers, self-aggregates and cargo complexes, distributed unevenly at the plasma membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Validation of Fluorescence Spectroscopy to Detect Adulteration of Edible Oil in Extra Virgin Olive Oil (EVOO) by Applying Chemometrics.

    Science.gov (United States)

    Ali, Hina; Saleem, Muhammad; Anser, Muhammad Ramzan; Khan, Saranjam; Ullah, Rahat; Bilal, Muhammad

    2018-01-01

    Due to high price and nutritional values of extra virgin olive oil (EVOO), it is vulnerable to adulteration internationally. Refined oil or other vegetable oils are commonly blended with EVOO and to unmask such fraud, quick, and reliable technique needs to be standardized and developed. Therefore, in this study, adulteration of edible oil (sunflower oil) is made with pure EVOO and analyzed using fluorescence spectroscopy (excitation wavelength at 350 nm) in conjunction with principal component analysis (PCA) and partial least squares (PLS) regression. Fluorescent spectra contain fingerprints of chlorophyll and carotenoids that are characteristics of EVOO and differentiated it from sunflower oil. A broad intense hump corresponding to conjugated hydroperoxides is seen in sunflower oil in the range of 441-489 nm with the maximum at 469 nm whereas pure EVOO has low intensity doublet peaks in this region at 441 nm and 469 nm. Visible changes in spectra are observed in adulterated EVOO by increasing the concentration of sunflower oil, with an increase in doublet peak and correspondingly decrease in chlorophyll peak intensity. Principal component analysis showed a distinct clustering of adulterated samples of different concentrations. Subsequently, the PLS regression model was best fitted over the complete data set on the basis of coefficient of determination (R 2 ), standard error of calibration (SEC), and standard error of prediction (SEP) of values 0.99, 0.617, and 0.623 respectively. In addition to adulterant, test samples and imported commercial brands of EVOO were also used for prediction and validation of the models. Fluorescence spectroscopy combined with chemometrics showed its robustness to identify and quantify the specified adulterant in pure EVOO.

  20. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    Science.gov (United States)

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg + ), ethylmercury (EtHg + ) and inorganic mercury (Hg 2+ ) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL -1 for EtHg + and 5-450ngL -1 for MeHg + and Hg 2+ . Limits of detection were 3.0ngL -1 for EtHg + and 1.5ngL -1 for MeHg + and Hg 2+ . Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Efficient encapsulation of chloroform with cryptophane-M and the formation of exciplex studied by fluorescence spectroscopy.

    Science.gov (United States)

    Shi, Yanqi; Li, Xueming; Yang, Jianchun; Gao, Fang; Tao, Chuanyi

    2011-03-01

    Efficient encapsulation of small molecules with supermolecules is one of significantly important subjects due to strong application potentials. This article presents the interaction between cryptophane-M and chloroform by fluorescence spectroscopy. The sonicated cryptophane-M solution exhibits light green color in chloroform, and the solid obtained from the evaporation of chloroform also has different color from that of cryptophane-M. In contrast, the sonicated cryptophane-M solutions in other solvents are colorless, and the solid obtained from the evaporation of these solvents has the same color as that of cryptophane-M. Furthermore, the freshly prepared cryptophane-M solution in different solvents is almost colorless, and the solid obtained from the evaporation of these solvents displays the same color as that of cryptophane-M. Although the sonicated cryptophane-M solutions in different solvents have very similar absorption spectra, they exhibit quite different emission spectra in chloroform. In contrast, the freshly-prepared cryptophane-M solutions show similar absorption and emission spectroscopy in various solvents. The variation of the fluorescence spectroscopy in binary solvents with the increasing chloroform ratio suggests that cryptophane-M and chloroform form a 1:1 exciplex, and the binding constant is estimated to be 292.95 M(-1). Although all solvents are able to enter into the cavity of cryptophane-M, only chloroform can stay in the cavity of cryptophane-M for a while, which is mostly due to the strong intermolecular interaction between cryptophane-M and chloroform, and this results in the formation of the exciplex between them. © Springer Science+Business Media, LLC 2010

  2. Solvent dependence of organic exciplex fluorescence studied by magnetic effect on reaction yield (M.A.R.Y) spectroscopy

    International Nuclear Information System (INIS)

    Pal, K.

    2011-01-01

    This work aims at understanding the various facets of one of the elementary reactions in nature, the electron transfer reaction using MARY (Magnetic effect on Reaction Yield) spectroscopy as a tool. The prime focus of study by the use this technique was the solvent dependence of organic exciplex fluorescence. Apart from that temperature dependent measurements using MARY spectroscopy have been performed to extract the activation energy parameters of electron transfer reaction. The discovery of magnetic field effect on new system was also a part of our study. The study of solvent dependence of organic exciplex fluorescence using MARY spectroscopy was carried out on the system of 9,10-dimethylanthracene (as the fluorophore) and N,N'-dimethylaniline and 4,4'-Bis(dimethylamino) diphenylmethane (as quenchers) in binary solvent mixtures of toluene/dimethylsulfoxide, benzylacetate/dimethylsulfoxide, toluene/propylenecarbonate and propylacetate/butyronitrile. The work focuses on the use of solvent mixtures rather than pure solvents. The solvent mixtures, tailored to simulate different microenvironemets, were employed to find out the effect of preferential solvation on electron transfer reaction. The contrast in the absolute field effect and linewidth values of the MARY spectra obtained in the four system as a function of dielectric constant scan suggest the imperative effect of concentration fluctuation on the electron transfer reaction. Temperature dependent measurements were performed on the system of N,N,N',N'- tetramethylparaphenylendiamin, photo-ionizing in a mixture of toluene/dimethylsulfoxide. However the sluggish response of the system to temperature changes does not really permit us to extract fruitful results. The magnetic field effect on the much studied system of Perylene/ N.N'-dimethylaniline was discovered for the first time. (author) [de

  3. Effect of tissue scaffold topography on protein structure monitored by fluorescence spectroscopy

    NARCIS (Netherlands)

    Portugal, C.A.M.; Truckenmüller, R.K.; Stamatialis, Dimitrios; Crespo, J.G.

    2014-01-01

    The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell–scaffold interactions. The changes induced upon adsorption

  4. Fluorescence correlation spectroscopy on electron transfer reactions : probing inter- and intramolecular redox processes

    NARCIS (Netherlands)

    Sen, S.

    2016-01-01

    We developed a new FRET-based technique, “Fluredox”, which allows fluorescence readout of the redox state of oxido-reductases at single molecule level. Commercially available red-absorbing fluorophore ATTO655 was selected for labeling Azurin, a small blue mononuclear copper protein. Single molecule

  5. Fluorescence Correlation Spectroscopy of Spermine-DNA Interactions - Nanostructure and Physical Supramolecular Chemistry of DNA Condensation

    Czech Academy of Sciences Publication Activity Database

    Kral, Teresa; Langner, M.; Hof, Martin; Adjimatera, N.; Blagbrough, I. S.

    2004-01-01

    Roč. 98, Supplement (2004), s22-s23 ISSN 0009-2770 Institutional research plan: CEZ:AV0Z4040901 Keywords : fluorescence * nanostructure * DNA condensation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.348, year: 2004

  6. Pleckstrin Homology Domain Diffusion in Dictyostelium Cytoplasm Studied Using Fluorescence Correlation Spectroscopy

    NARCIS (Netherlands)

    Engel, Ruchira; Hink, Mark A.; Bosgraaf, Leonard; Haastert, Peter J.M. van; Visser, Antonie J.W.G.

    2004-01-01

    The translocation of pleckstrin homology (PH) domain-containing proteins from the cytoplasm to the plasma membrane plays an important role in the chemotaxis mechanism of Dictyostelium cells. The diffusion of three PH domain-green fluorescent protein (GFP) fusions (PH2-GFP, PH10-GFP, and PH-CRAC

  7. Pleckstrin homology domain diffusion in Dictyostelium cytoplasm studied using fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    Ruchira, A.; Hink, M.A.; Bosgraaf, L.; Haastert, van P.J.M.; Visser, A.J.W.G.

    2004-01-01

    The translocation of pleckstrin homology (PH) domain-containing proteins from the cytoplasm to the plasma membrane plays an important role in the chemotaxis mechanism of Dictyostelium cells. The diffusion of three PH domain-green fluorescent protein (GFP) fusions (PH2-GFP, PH10-GFP, and PH-CRAC

  8. Characterization of caries progression on dentin after irradiation with Nd:YAG laser by FTIR spectroscopy and fluorescence imaging

    Science.gov (United States)

    Ana, P. A.; Brito, A. M. M.; Zezell, D. M.; Lins, E. C. C. C.

    2015-06-01

    Considering the use of high intensity lasers for preventing dental caries, this blind in vitro study evaluated the compositional and fluorescence effects promoted by Nd:YAG laser (λ=1064 nm) when applied for prevention of progression of dentin caries, in association or not with topical application of acidulated phosphate fluoride (APF). Sixty bovine root dentin slabs were prepared and demineralized by 32h in order to create early caries lesions. After, the slabs were distributed into six experimental groups: G1- untreated and not submitted to a pH-cycling model; G2- untreated and submitted to a pH-cycling model; G3- acidulated phosphate fluoride application (APF); G4- Nd:YAG irradiation (84.9 J/cm2, 60 mJ/pulse); G5- treated with Nd:YAG+APF; G6- treated with APF+Nd:YAG. After treatments, the samples of groups G2 to G6 were submitted to a 4-day pH-cycling model in order to simulate the progression of early caries lesions. All samples were characterized by the micro-attenuated total reflection technique of Fourier transformed infrared spectroscopy (μATR-FTIR), using a diamond crystal, and by a fluorescence imaging system (FIS), in which it was used an illuminating system at λ= 405±30 nm. Demineralization promoted reduction in carbonate and phosphate contents, exposing the organic matter; as well, it was observed a significant reduction of fluorescence intensity. Nd:YAG laser promoted additional chemical changes, and increased the fluorescence intensity even with the development of caries lesions. It was concluded that the compositional changes promoted by Nd:YAG, when associated to APF, are responsible for the reduction of demineralization progression observed on root dentin.

  9. A flexible fluorescence correlation spectroscopy based method for quantification of the DNA double labeling efficiency with precision control

    International Nuclear Information System (INIS)

    Hou, Sen; Tabaka, Marcin; Sun, Lili; Trochimczyk, Piotr; Kaminski, Tomasz S; Kalwarczyk, Tomasz; Zhang, Xuzhu; Holyst, Robert

    2014-01-01

    We developed a laser-based method to quantify the double labeling efficiency of double-stranded DNA (dsDNA) in a fluorescent dsDNA pool with fluorescence correlation spectroscopy (FCS). Though, for quantitative biochemistry, accurate measurement of this parameter is of critical importance, before our work it was almost impossible to quantify what percentage of DNA is doubly labeled with the same dye. The dsDNA is produced by annealing complementary single-stranded DNA (ssDNA) labeled with the same dye at 5′ end. Due to imperfect ssDNA labeling, the resulting dsDNA is a mixture of doubly labeled dsDNA, singly labeled dsDNA and unlabeled dsDNA. Our method allows the percentage of doubly labeled dsDNA in the total fluorescent dsDNA pool to be measured. In this method, we excite the imperfectly labeled dsDNA sample in a focal volume of <1 fL with a laser beam and correlate the fluctuations of the fluorescence signal to get the FCS autocorrelation curves; we express the amplitudes of the autocorrelation function as a function of the DNA labeling efficiency; we perform a comparative analysis of a dsDNA sample and a reference dsDNA sample, which is prepared by increasing the total dsDNA concentration c (c > 1) times by adding unlabeled ssDNA during the annealing process. The method is flexible in that it allows for the selection of the reference sample and the c value can be adjusted as needed for a specific study. We express the precision of the method as a function of the ssDNA labeling efficiency or the dsDNA double labeling efficiency. The measurement precision can be controlled by changing the c value. (letter)

  10. [Rapid Identification of Epicarpium Citri Grandis via Infrared Spectroscopy and Fluorescence Spectrum Imaging Technology Combined with Neural Network].

    Science.gov (United States)

    Pan, Sha-sha; Huang, Fu-rong; Xiao, Chi; Xian, Rui-yi; Ma, Zhi-guo

    2015-10-01

    To explore rapid reliable methods for detection of Epicarpium citri grandis (ECG), the experiment using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy (FTIR/ATR) and Fluorescence Spectrum Imaging Technology combined with Multilayer Perceptron (MLP) Neural Network pattern recognition, for the identification of ECG, and the two methods are compared. Infrared spectra and fluorescence spectral images of 118 samples, 81 ECG and 37 other kinds of ECG, are collected. According to the differences in tspectrum, the spectra data in the 550-1 800 cm(-1) wavenumber range and 400-720 nm wavelength are regarded as the study objects of discriminant analysis. Then principal component analysis (PCA) is applied to reduce the dimension of spectroscopic data of ECG and MLP Neural Network is used in combination to classify them. During the experiment were compared the effects of different methods of data preprocessing on the model: multiplicative scatter correction (MSC), standard normal variable correction (SNV), first-order derivative(FD), second-order derivative(SD) and Savitzky-Golay (SG). The results showed that: after the infrared spectra data via the Savitzky-Golay (SG) pretreatment through the MLP Neural Network with the hidden layer function as sigmoid, we can get the best discrimination of ECG, the correct percent of training set and testing set are both 100%. Using fluorescence spectral imaging technology, corrected by the multiple scattering (MSC) results in the pretreatment is the most ideal. After data preprocessing, the three layers of the MLP Neural Network of the hidden layer function as sigmoid function can get 100% correct percent of training set and 96.7% correct percent of testing set. It was shown that the FTIR/ATR and fluorescent spectral imaging technology combined with MLP Neural Network can be used for the identification study of ECG and has the advantages of rapid, reliable effect.

  11. Complementary studies of lipid membrane dynamics using iSCAT and super-resolved fluorescence correlation spectroscopy

    Science.gov (United States)

    Reina, Francesco; Galiani, Silvia; Shrestha, Dilip; Sezgin, Erdinc; de Wit, Gabrielle; Cole, Daniel; Lagerholm, B. Christoffer; Kukura, Philipp; Eggeling, Christian

    2018-06-01

    Observation techniques with high spatial and temporal resolution, such as single-particle tracking based on interferometric scattering (iSCAT) microscopy, and fluorescence correlation spectroscopy applied on a super-resolution STED microscope (STED-FCS), have revealed new insights of the molecular organization of membranes. While delivering complementary information, there are still distinct differences between these techniques, most prominently the use of fluorescent dye tagged probes for STED-FCS and a need for larger scattering gold nanoparticle tags for iSCAT. In this work, we have used lipid analogues tagged with a hybrid fluorescent tag–gold nanoparticle construct, to directly compare the results from STED-FCS and iSCAT measurements of phospholipid diffusion on a homogeneous supported lipid bilayer (SLB). These comparative measurements showed that while the mode of diffusion remained free, at least at the spatial (>40 nm) and temporal (50  ⩽  t  ⩽  100 ms) scales probed, the diffussion coefficient was reduced by 20- to 60-fold when tagging with 20 and 40 nm large gold particles as compared to when using dye tagged lipid analogues. These FCS measurements of hybrid fluorescent tag–gold nanoparticle labeled lipids also revealed that commercially supplied streptavidin-coated gold nanoparticles contain large quantities of free streptavidin. Finally, the values of apparent diffusion coefficients obtained by STED-FCS and iSCAT differed by a factor of 2–3 across the techniques, while relative differences in mobility between different species of lipid analogues considered were identical in both approaches. In conclusion, our experiments reveal that large and potentially cross-linking scattering tags introduce a significant slow-down in diffusion on SLBs but no additional bias, and our labeling approach creates a new way of exploiting complementary information from STED-FCS and iSCAT measurements.

  12. Binding of Cu(II) ions to peptides studied by fluorescence spectroscopy and isothermal titration calorimetry

    Science.gov (United States)

    Makowska, Joanna; Żamojć, Krzysztof; Wyrzykowski, Dariusz; Uber, Dorota; Wierzbicka, Małgorzata; Wiczk, Wiesław; Chmurzyński, Lech

    2016-01-01

    Steady-state and time-resolved fluorescence quenching measurements supported by Isothermal Titration Calorimetry (ITC) were used to study the interactions of Cu2 + with four peptides. Two of them were taken from the N-terminal part of the FBP28 protein (formin binding protein) WW domain: Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr-NH2 (D9) and its mutant Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr-NH2 (D9_M) as well as two mutated peptides from the B3 domain of the immunoglobulin binding protein G derived from Streptococcus: Asp-Val-Ala-Thr-Tyr-Thr-NH2 (J1) and Glu-Val-Ala-Thr-Tyr-Thr-NH2 (J2). The measurements were carried out at 298.15 K in 20 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution with a pH of 6. The fluorescence of all peptides was quenched by Cu2 + ions. The stoichiometry, conditional stability constants and thermodynamic parameters for the interactions of the Cu2 + ions with D9 and D9_M were determined from the calorimetric data. The values of the conditional stability constants were additionally determined from fluorescence quenching measurements and compared with those obtained from calorimetric studies. There was a good correlation between data obtained from the two techniques. On the other hand, the studies revealed that J1 and J2 do not exhibit an affinity towards metal ions. The obtained results prove that fluorescence quenching experiments may be successfully used in order to determine stability constants of complexes with fluorescent ligands. Finally, based on the obtained results, the coordinating properties of the peptides towards the Cu2 + ions are discussed.

  13. Binding of Cu(II) ions to peptides studied by fluorescence spectroscopy and isothermal titration calorimetry.

    Science.gov (United States)

    Makowska, Joanna; Żamojć, Krzysztof; Wyrzykowski, Dariusz; Uber, Dorota; Wierzbicka, Małgorzata; Wiczk, Wiesław; Chmurzyński, Lech

    2016-01-15

    Steady-state and time-resolved fluorescence quenching measurements supported by Isothermal Titration Calorimetry (ITC) were used to study the interactions of Cu(2+) with four peptides. Two of them were taken from the N-terminal part of the FBP28 protein (formin binding protein) WW domain: Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr-NH2 (D9) and its mutant Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr-NH2 (D9_M) as well as two mutated peptides from the B3 domain of the immunoglobulin binding protein G derived from Streptococcus: Asp-Val-Ala-Thr-Tyr-Thr-NH2 (J1) and Glu-Val-Ala-Thr-Tyr-Thr-NH2 (J2). The measurements were carried out at 298.15K in 20mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution with a pH of 6. The fluorescence of all peptides was quenched by Cu(2+) ions. The stoichiometry, conditional stability constants and thermodynamic parameters for the interactions of the Cu(2+) ions with D9 and D9_M were determined from the calorimetric data. The values of the conditional stability constants were additionally determined from fluorescence quenching measurements and compared with those obtained from calorimetric studies. There was a good correlation between data obtained from the two techniques. On the other hand, the studies revealed that J1 and J2 do not exhibit an affinity towards metal ions. The obtained results prove that fluorescence quenching experiments may be successfully used in order to determine stability constants of complexes with fluorescent ligands. Finally, based on the obtained results, the coordinating properties of the peptides towards the Cu(2+) ions are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Assessment of high precision, high accuracy Inductively Coupled Plasma-Optical Emission Spectroscopy to obtain concentration uncertainties less than 0.2% with variable matrix concentrations

    International Nuclear Information System (INIS)

    Rabb, Savelas A.; Olesik, John W.

    2008-01-01

    The ability to obtain high precision, high accuracy measurements in samples with complex matrices using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy (HP-ICP-OES) was investigated. The Common Analyte Internal Standard (CAIS) procedure was incorporated into the High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method to correct for matrix-induced changes in emission intensity ratios. Matrix matching and standard addition approaches to minimize matrix-induced errors when using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy were also assessed. The High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method was tested with synthetic solutions in a variety of matrices, alloy standard reference materials and geological reference materials

  15. Study of the heavy impurity influx into the plasma using laser fluorescence spectroscopy in the TO-2 tokamak with toroidal divertor

    International Nuclear Information System (INIS)

    Vukolov, K.Yu.; Shvindt, N.N.

    1992-01-01

    Measurement cycle for determination of iron atom absolute concentrations was carried out in divertor and diaphragm modes of laser fluorescence spectroscopy. The conclusion is made on effective wall shielding by divertor layer as compared to material diaphragm. The basic result of the work consists in creating and testing on the tokamak TO-2 of multichannel diagnostic complex for remote measurement of atom (ion) absolute concentrations of metallic impurities in the near-wall plasma with high spatial and time resolution through laser fluorescence spectroscopy method intended for studies at the Tokamak-15 facility

  16. A LabVIEW-Based Virtual Instrument System for Laser-Induced Fluorescence Spectroscopy.

    Science.gov (United States)

    Wu, Qijun; Wang, Lufei; Zu, Lily

    2011-01-01

    We report the design and operation of a Virtual Instrument (VI) system based on LabVIEW 2009 for laser-induced fluorescence experiments. This system achieves synchronous control of equipment and acquisition of real-time fluorescence data communicating with a single computer via GPIB, USB, RS232, and parallel ports. The reported VI system can also accomplish data display, saving, and analysis, and printing the results. The VI system performs sequences of operations automatically, and this system has been successfully applied to obtain the excitation and dispersion spectra of α-methylnaphthalene. The reported VI system opens up new possibilities for researchers and increases the efficiency and precision of experiments. The design and operation of the VI system are described in detail in this paper, and the advantages that this system can provide are highlighted.

  17. Applications of Fourier transform infrared spectroscopy to quality control of the epoxy matrix

    Science.gov (United States)

    Antoon, M. K.; Starkey, K. M.; Koenig, J. L.

    1979-01-01

    The object of the paper is to demonstrate the utility of Fourier transform infrared (FT-IR) difference spectra for investigating the composition of a neat epoxy resin, hardener, and catalysts. The composition and degree of cross-linking of the cured matrix is also considered.

  18. Alpha particle spectroscopy for CR-39 detector utilizing matrix of energy equations

    Energy Technology Data Exchange (ETDEWEB)

    Awad, E.M. [Department of General Sciences, Yanbu Industrial College, PO Box 30436, Madinat Yanbu Al-Sinaiya (Saudi Arabia); Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)], E-mail: ayawad@yahoo.com; Soliman, A.A. [Department of Mathematics, Faculty of Education (AL-Arish), Suez Canal University, AL-Arish 45111 (Egypt); Department of Mathematics, Teacher' s College (Bisha), King Khalid University, Bisha, PO Box 551 (Saudi Arabia)], E-mail: asoliman_99@yahoo.com; Rammah, Y.S. [Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)

    2007-10-01

    A method for determining alpha-particle energy using CR-39 detector by utilizing matrix of energy equation was described. The matrix was composed from two axes; the track minor axis (m) and diameter of etched out track end (d) axis of some selected elliptical tracks. The energy E in (m,d) coordinate was approximated by matrix of energy equations given by: E{sub k}={sigma}{sub i,j=0}{sup 2}a{sub ij}d{sub k}{sup i}m{sub k}{sup j}, which was identified using two different approaches. First, i and j were treated as power exponents for d and m. The adjusting parameters values a{sub ij} were obtained and the energy of a given track was deduced directly from it. Second, i and j were treated as indices of some chosen tracks that were fitted to obtain iso-energy curves that were superimposed on m-d scatter plot as calibration curves. The energy between any two successive iso-energy curves in this case was assumed varied linearly with d for a given m. The energy matrix in both cases was solved numerically. Results of the two approaches were compared.

  19. Elucidation of Prion Protein Conformational Changes Associated with Infectivity by Fluorescence Spectroscopy

    Science.gov (United States)

    2007-06-01

    is not known. Obtaining structural information on the misfolded isoform of prion may lead to preventative therapies and treatments of prion diseases...the misfolded prion isoform may allow for the development of drug therapies or early detection systems for prion diseases, or illuminate mechanistic...showing fluorescence intensity as a function of time and energy for 2,6-p-toluidinonapththalene adsorbed to egg L-α- lecithin vesicles. The steady

  20. Photo-induced processes in collagen-hypericin system revealed by fluorescence spectroscopy and multiphoton microscopy

    OpenAIRE

    Hovhannisyan, V.; Guo, H. W.; Hovhannisyan, A.; Ghukasyan, V.; Buryakina, T.; Chen, Y. F.; Dong, C. Y.

    2014-01-01

    Collagen is the main structural protein and the key determinant of mechanical and functional properties of tissues and organs. Proper balance between synthesis and degradation of collagen molecules is critical for maintaining normal physiological functions. In addition, collagen influences tumor development and drug delivery, which makes it a potential cancer therapy target. Using second harmonic generation, two-photon excited fluorescence microscopy, and spectrofluorimetry, we show that the ...

  1. Smartphone-based fluorescence spectroscopy device aiding in preliminary skin screening

    Science.gov (United States)

    Sahoo, Aparajita; Wahi, Akshat; Das, Anshuman

    2018-02-01

    Preliminary diagnosis of closely resembling skin conditions can be highly subjective for dermatologists. In ambiguous cases, it often leads to performing invasive procedures like biopsies. Different skin conditions, however, have varying concentrations of fluorophores (like collagen, NADH) and chromophores (like melanin, hemoglobin) which can alter their fluorescence spectra. We demonstrate a handheld, portable, smartphone-based spectrometer that leverages these alterations in skin autofluorescence spectra for rapid screening of skin conditions. This methodology involves excitation of affected skin areas with ultraviolet (UV-A) 385 nm light, capturing the generated fluorescence spectra and sending the data wirelessly to a companion mobile application for data storage, analysis and visualization. By collecting the fluorescence spectral signals from healthy and unhealthy skin conditions, we establish that the signals collected using this portable device can be used to develop a classification method to help in differentially diagnosing these conditions. It shows promise as a useful skin screening tool for both dermatologists and primary health care workers. This device can enable quick, non-invasive and a more objective preliminary examination. We envision the device to be especially useful in primary healthcare centers of developing countries where availability of dermatologists is limited.

  2. Three-dimensional excitation and emission matrix fluorescence (3DEEM) for quick and pseudo-quantitative determination of protein- and humic-like substances in full-scale membrane bioreactor (MBR).

    Science.gov (United States)

    Jacquin, Céline; Lesage, Geoffroy; Traber, Jacqueline; Pronk, Wouter; Heran, Marc

    2017-07-01

    The goal of this study is to help filling the research gaps linked to the on-line application of fluorescence spectroscopy in wastewater treatment and data processing tools suitable for rapid correction and extraction of data contained in three-dimensional fluorescence excitation-emission matrix (3DEEM) for real-time studies. 3DEEM was evaluated for direct quantification of Effluent Organic Matter (EfOM) fractions in full-scale MBR bulk supernatant and permeate samples. Principal Component Analysis (PCA) was used to investigate possible correlations between conventional Lowry and Dubois methods, Liquid Chromatography coupled to Organic Carbon and Organic Nitrogen Detection (LC-OCD-OND) and 3DEEM. 3DEEM data were analyzed using the volume of fluorescence (Φ) parameter from the Fluorescence Regional Integration (FRI) method. Two mathematical correlations were established between LC-OCD-OND and 3DEEM data to quantify protein-like and humic-like substances. These correlations were validated with supplementary data from the initial full-scale MBR, and were checked with samples from other systems (a second full-scale MBR, a full-scale conventional activated sludge (CAS) and a laboratory-scale MBR). While humic-like correlation showed satisfactory prediction for a second full-scale MBR and a CAS system, further studies are required for protein-like estimation in other systems. This new approach offers interesting perspectives for the on-line application of 3DEEM for EfOM quantification (protein-like and humic-like substances), fouling prediction and MBR process control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Changes in chemical composition of bone matrix in ovariectomized (OVX) rats detected by Raman spectroscopy and multivariate analysis

    Science.gov (United States)

    Oshima, Yusuke; Iimura, Tadahiro; Saitou, Takashi; Imamura, Takeshi

    2015-02-01

    Osteoporosis is a major bone disease that connotes the risk of fragility fractures resulting from alterations to bone quantity and/or quality to mechanical competence. Bone strength arises from both bone quantity and quality. Assessment of bone quality and bone quantity is important for prediction of fracture risk. In spite of the two factors contribute to maintain the bone strength, only one factor, bone mineral density is used to determine the bone strength in the current diagnosis of osteoporosis. On the other hand, there is no practical method to measure chemical composition of bone tissue including hydroxyapatite and collagen non-invasively. Raman spectroscopy is a powerful technique to analyze chemical composition and material properties of bone matrix non-invasively. Here we demonstrated Raman spectroscopic analysis of the bone matrix in osteoporosis model rat. Ovariectomized (OVX) rat was made and the decalcified sections of tibias were analyzed by a Raman microscope. In the results, Raman bands of typical collagen appeared in the obtained spectra. Although the typical mineral bands at 960 cm-1 (Phosphate) was absent due to decalcified processing, we found that Raman peak intensities of amide I and C-C stretching bands were significantly different between OVX and sham-operated specimens. These differences on the Raman spectra were statistically compared by multivariate analyses, principal component analysis (PCA) and liner discrimination analysis (LDA). Our analyses suggest that amide I and C-C stretching bands can be related to stability of bone matrix which reflects bone quality.

  4. Laser induced fluorescence and phosphorescence of matrix isolated glyoxal - Evidence for exciplex formation in the A 1Au and a 3Au states

    Science.gov (United States)

    Van Ijzendoorn, L. J.; Baas, F.; Koernig, S.; Greenberg, J. M.; Allamandola, L. J.

    1986-01-01

    Laser-induced fluorescence and phosphorescence as well as infrared and visible absorption spectra of glyoxal in Ar, N2, and CO matrices are presented and analyzed. Glyoxal in its first excited electronic state is shown to form an exciplex with its nearest neighbors in all three matrices, and transitions normally forbidden dominate the emission spectra. The spectral characteristics of these complexes are similar to those of the Ar-glyoxal complex found in supersonic beam experiments. Due to the matrix cage effect, no vibrational predissociation is observed. The phosphorescence lifetime is determined and an upper limit is given for the fluorescence lifetime. This, in combination with the relative intensities of fluorescence and phosphorescence, can be used to place limits on the quantum yields of the various relaxation processes.

  5. Novel Insight for Organic Matter Sourcing: Interest of Time Resolved Fluorescence to Qualify and Quantify PAH Content of Solid Matrix at High Resolution

    Science.gov (United States)

    Quiers, M.; Perrette, Y.; Jacq, K.; Pousset, E.; Plassart, G.

    2017-12-01

    OM fluorescence is today a well-developed tool used to characterize and quantify organic matter (OM), but also to evaluate and discriminate OM fate and changes related to climate and environmental modifications. While fluorescence measurements on water and soils extracts provide information about organic fluxes today, solid phase fluorescence using natural archives allows to obtain high resolution records of OM evolution during time. These evolutions can be discussed in regards of climate and environmental perturbations detected in archives using different proxies, and thus provide keys for understanding factors driving carbon fluxes mechanisms. Among fluorescent organic species, Polycyclic Aromatic Hydrocarbons (PAH) have been used as probe molecules for organic contamination tracking. Moreover, monitoring studies have shown that PAH could also be used as markers to discriminates atmospheric and erosion factors leading to PAH and organic matter fluxes to the aquifer. PAH records in soils and natural archives appear as a promising proxy to follow both past atmospheric contamination and soil erosion. But, PAH fluorescence is difficult to discriminate from bulk OM fluorescence using steady-state fluorescence (SSF) technics as their fluorescence domains recover. Time resolved emission spectroscopy (TRES) increases the information provided by SSF technic, adding a time dimension to measurements and allowing to discriminate PAH fluorescence. We report here a first application of this technic on natural archives. The challenge is to obtain TRES signature along the sample, including for low PAH concentrations. This study aims to evaluate the reliability of high resolution TRES measurement as PAH carbon fluxes sources. Method is based on LIF instrument for solid phase fluorescence measurement. An instrument coupling an excitation system constituting by 2 pulsed lasers (266 and 355 nm) and a detection system was developed. This measurement provides high resolution record of

  6. Insight into the heterogeneous adsorption of humic acid fluorescent components on multi-walled carbon nanotubes by excitation-emission matrix and parallel factor analysis.

    Science.gov (United States)

    Yang, Chenghu; Liu, Yangzhi; Cen, Qiulin; Zhu, Yaxian; Zhang, Yong

    2018-02-01

    The heterogeneous adsorption behavior of commercial humic acid (HA) on pristine and functionalized multi-walled carbon nanotubes (MWCNTs) was investigated by fluorescence excitation-emission matrix and parallel factor (EEM- PARAFAC) analysis. The kinetics, isotherms, thermodynamics and mechanisms of adsorption of HA fluorescent components onto MWCNTs were the focus of the present study. Three humic-like fluorescent components were distinguished, including one carboxylic-like fluorophore C1 (λ ex /λ em = (250, 310) nm/428nm), and two phenolic-like fluorophores, C2 (λ ex /λ em = (300, 460) nm/552nm) and C3 (λ ex /λ em = (270, 375) nm/520nm). The Lagergren pseudo-second-order model can be used to describe the adsorption kinetics of the HA fluorescent components. In addition, both the Freundlich and Langmuir models can be suitably employed to describe the adsorption of the HA fluorescent components onto MWCNTs with significantly high correlation coefficients (R 2 > 0.94, Padsorption affinity (K d ) and nonlinear adsorption degree from the HA fluorescent components to MWCNTs was clearly observed. The adsorption mechanism suggested that the π-π electron donor-acceptor (EDA) interaction played an important role in the interaction between HA fluorescent components and the three MWCNTs. Furthermore, the values of the thermodynamic parameters, including the Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°), showed that the adsorption of the HA fluorescent components on MWCNTs was spontaneous and exothermic. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Matrix effect on the detection limit and accuracy in total reflection X-ray fluorescence analysis of trace elements in environmental and biological samples

    International Nuclear Information System (INIS)

    Karjou, J.

    2007-01-01

    The effect of matrix contents on the detection limit of total reflection X-ray fluorescence analysis was experimentally investigated using a set of multielement standard solutions (500 ng/mL of each element) in variable concentrations of NH 4 NO 3 . It was found that high matrix concentration, i.e. 0.1-10% NH 4 NO 3 , had a strong effect on the detection limits for all investigated elements, whereas no effect was observed at lower matrix concentration, i.e. 0-0.1% NH 4 NO 3 . The effect of soil and blood sample masses on the detection limit was also studied. The results showed decreasing the detection limit (in concentration unit, μg/g) with increasing the sample mass. However, the detection limit increased (in mass unit, ng) with increasing sample mass. The optimal blood sample mass of ca. 200 μg was sufficient to improve the detection limit of Se determination by total reflection X-ray fluorescence. The capability of total reflection X-ray fluorescence to analyze different kinds of samples was discussed with respect to the accuracy and detection limits based on certified and reference materials. Direct analysis of unknown water samples from several sources was also presented in this work

  8. Localizing internal friction along the reaction coordinate of protein folding by combining ensemble and single-molecule fluorescence spectroscopy

    Science.gov (United States)

    Borgia, Alessandro; Wensley, Beth G.; Soranno, Andrea; Nettels, Daniel; Borgia, Madeleine B.; Hoffmann, Armin; Pfeil, Shawn H.; Lipman, Everett A.; Clarke, Jane; Schuler, Benjamin

    2012-01-01

    Theory, simulations and experimental results have suggested an important role of internal friction in the kinetics of protein folding. Recent experiments on spectrin domains provided the first evidence for a pronounced contribution of internal friction in proteins that fold on the millisecond timescale. However, it has remained unclear how this contribution is distributed along the reaction and what influence it has on the folding dynamics. Here we use a combination of single-molecule Förster resonance energy transfer, nanosecond fluorescence correlation spectroscopy, microfluidic mixing and denaturant- and viscosity-dependent protein-folding kinetics to probe internal friction in the unfolded state and at the early and late transition states of slow- and fast-folding spectrin domains. We find that the internal friction affecting the folding rates of spectrin domains is highly localized to the early transition state, suggesting an important role of rather specific interactions in the rate-limiting conformational changes. PMID:23149740

  9. Time-resolved spectroscopy and fluorescence resonance energy transfer in the study of excimer laser damage of chromatin

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L. [Department of Molecular Genetics and Radiobiology, Babes National Institute, Bucharest (Romania)], E-mail: lilianajradu@yahoo.fr; Mihailescu, I. [Department of Lasers, Laser, Plasma and Radiation Physics Institute, Bucharest (Romania); Radu, S. [Department of Computer Science, Polytechnics University, Bucharest (Romania); Gazdaru, D. [Department of Biophysics, Bucharest University (Romania)

    2007-09-21

    The analysis of chromatin damage produced by a 248 nm excimer laser radiation, for doses of 0.3-3 MJ/m{sup 2} was carried out by time-resolved spectroscopy and fluorescence resonance energy transfer (FRET). The chromatin was extracted from a normal and a tumoral tissue of Wistar rats. The decrease with laser dose of the relative contribution of the excited state lifetimes of ethidium bromide (EtBr) bounded to chromatin constitutes an evidence of the reduction of chromatin deoxyribonucleic acid (DNA) double-strand structure. FRET was performed from dansyl chloride to acridine orange, both coupled to chromatin. The increase of the average distance between these ligands, under the action of laser radiation, reflects a loosening of the chromatin structure. The radiosensitivity of tumor tissue chromatin is higher than that of a normal tissue. The determination of the chromatin structure modification in an excimer laser field can be of interest in laser therapy.

  10. Time-resolved spectroscopy and fluorescence resonance energy transfer in the study of excimer laser damage of chromatin

    International Nuclear Information System (INIS)

    Radu, L.; Mihailescu, I.; Radu, S.; Gazdaru, D.

    2007-01-01

    The analysis of chromatin damage produced by a 248 nm excimer laser radiation, for doses of 0.3-3 MJ/m 2 was carried out by time-resolved spectroscopy and fluorescence resonance energy transfer (FRET). The chromatin was extracted from a normal and a tumoral tissue of Wistar rats. The decrease with laser dose of the relative contribution of the excited state lifetimes of ethidium bromide (EtBr) bounded to chromatin constitutes an evidence of the reduction of chromatin deoxyribonucleic acid (DNA) double-strand structure. FRET was performed from dansyl chloride to acridine orange, both coupled to chromatin. The increase of the average distance between these ligands, under the action of laser radiation, reflects a loosening of the chromatin structure. The radiosensitivity of tumor tissue chromatin is higher than that of a normal tissue. The determination of the chromatin structure modification in an excimer laser field can be of interest in laser therapy

  11. The development of methods of analysis of documents on the basis of the methods of Raman spectroscopy and fluorescence analysis

    Science.gov (United States)

    Gorshkova, Kseniia O.; Tumkin, Ilya I.; Kirillova, Elizaveta O.; Panov, Maxim S.; Kochemirovsky, Vladimir A.

    2017-05-01

    The investigation of natural aging of writing inks printed on paper using Raman spectroscopy was performed. Based on the obtained dependencies of the Raman peak intensities ratios on the exposure time, the dye degradation model was proposed. It was suggested that there are several competing bond breaking and bond forming reactions corresponding to the characteristic vibration frequencies of the dye molecule that simultaneously occur during ink aging process. Also we propose a methodology based on the study of the optical properties of paper, particularly changes in the fluorescence of optical brighteners included in its composition as well as the paper reflectivity using spectrophotometric methods. These results can be implemented to develop the novel and promising method of criminology.

  12. Quantifying the number of color centers in single fluorescent nanodiamonds by photon correlation spectroscopy and Monte Carlo simulation

    International Nuclear Information System (INIS)

    Hui, Y.Y.; Chang, Y.-R.; Lee, H.-Y.; Chang, H.-C.; Lim, T.-S.; Fann Wunshain

    2009-01-01

    The number of negatively charged nitrogen-vacancy centers (N-V) - in fluorescent nanodiamond (FND) has been determined by photon correlation spectroscopy and Monte Carlo simulations at the single particle level. By taking account of the random dipole orientation of the multiple (N-V) - fluorophores and simulating the probability distribution of their effective numbers (N e ), we found that the actual number (N a ) of the fluorophores is in linear correlation with N e , with correction factors of 1.8 and 1.2 in measurements using linearly and circularly polarized lights, respectively. We determined N a =8±1 for 28 nm FND particles prepared by 3 MeV proton irradiation

  13. Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: Pressure and temperature dependence and the density scaling

    Science.gov (United States)

    Meier, G.; Gapinski, J.; Ratajczyk, M.; Lettinga, M. P.; Hirtz, K.; Banachowicz, E.; Patkowski, A.

    2018-03-01

    The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.

  14. Nanoporous Structure of Bone Matrix at Osteoporosis from Data of Atomic Force Microscopy and IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    A. A. Gaidash

    2011-01-01

    Full Text Available It was found that in an osteoporotic bone the fraction of nanosized pores decreases, the mineral phase amorphizes, hydrated shells around mineralized particles of the bone matrix thicken, and adhesion forces increase. This contributes to the formation of water clusters similar to bulk water clusters compared to the healthy bone tissue and leads to the accumulation of more viscous liquid with increased intermolecular interaction forces in the pores of the bone matrix. Given this, the rates of chemical reactions proceeding in the water phase of ultrathin channels of general parts of collagen fibrils decrease. Ultimately, nanopores of collagen-apatite interfaces lose, to a certain extent, the capability of catalyzing the hydroxyapatite crystallization.

  15. Characterization of ceramic matrix composite degradation using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Henry, Christine; Criner, Amanda Keck; Imel, Megan; King, Derek

    2018-04-01

    Data collected with a handheld Fourier Transform Infrared (FTIR) device is analyzed and considered as a useful method for detecting and quantifying oxidation on the surface of ceramic matrix composite (CMC) materials. Experiments examine silicon carbide (SiC) coupons, looking for changes in chemical composition before and after thermal exposure. Using mathematical, physical and statistical models for FTIR reflectance data, this research seeks to quantify any detected spectral changes as an indicator of surface oxidation on the CMC coupon.

  16. High resolution VUV matrix isolation spectroscopy using synchrotron radiation: N2 in Ne

    International Nuclear Information System (INIS)

    Guertler, P.; Koch, E.E.

    1980-01-01

    We have investigated the VUV absorption spectrum of nitrogen in a neon matrix exploiting the intense synchrotron radiation continuum of the storage ring DORIS and the high resolving power of a 3 m normal incidence monochromator. With an improved sample preparation technique we were able to observe both the allowed transitions b 1 PIsub(u) and b 1 Σ + sub(u) between 12.4 and 14.0 eV and even the forbidden transitions w 1 Δsub(u) and a 1 PIsub(g) between 8.0 and 11.0 eV. All four transitions consist of long progressions of sharp bands (GAMMA approx. 10 meV) which are deperturbed in the matrix due to the suppression of nearby Rydberg states. Using symmetry arguments, our analysis of the spectra leads us to the conclusion that the N 2 molecule is oriented along the (1,1,1) direction in the host lattice. A detailed fine structure is observed for most bands of the first time. This fine structure is caused by dynamical interactions of the excited molecules with the matrix and is interpreted as excitation of librational modes of the N 2 molecule and a selective coupling to phonon modes of the neon lattice. (orig.)

  17. Dilution effect on the U 5f states in Au matrix: a photoemission spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Eloirdi, R.; Gouder, T.; Wastin, F.; Huber, F.; Shick, Alexander; Kolorenč, Jindřich

    2011-01-01

    Roč. 84, č. 23 (2011), 235143/1-235143/7 ISSN 1098-0121 R&D Projects: GA ČR(CZ) GAP204/10/0330; GA AV ČR IAA100100912 Institutional research plan: CEZ:AV0Z10100520 Keywords : x-ray photoemission * electronic-structure * photoelectron- spectroscopy * fermion systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

  18. Quantification of Material Fluorescence and Light Scattering Cross Sections Using Ratiometric Bandwidth-Varied Polarized Resonance Synchronous Spectroscopy.

    Science.gov (United States)

    Xu, Joanna Xiuzhu; Hu, Juan; Zhang, Dongmao

    2018-05-25

    Presented herein is the ratiometric bandwidth-varied polarized resonance synchronous spectroscopy (BVPRS2) method for quantification of material optical activity spectra. These include the sample light absorption and scattering cross-section spectrum, the scattering depolarization spectrum, and the fluorescence emission cross-section and depolarization spectrum in the wavelength region where the sample both absorbs and emits. This ratiometric BVPRS2 spectroscopic method is a self-contained technique capable of quantitatively decoupling material fluorescence and light scattering signal contribution to its ratiometric BVPRS2 spectra through the linear curve-fitting of the ratiometric BVPRS2 signal as a function of the wavelength bandwidth used in the PRS2 measurements. Example applications of this new spectroscopic method are demonstrated with materials that can be approximated as pure scatterers, simultaneous photon absorbers/emitters, simultaneous photon absorbers/scatterers, and finally simultaneous photon absorbers/scatterers/emitters. Because the only instruments needed for this ratiometric BVPRS2 technique are the conventional UV-vis spectrophotometer and spectrofluorometer, this work should open doors for routine decomposition of material UV-vis extinction spectrum into its absorption and scattering component spectra. The methodology and insights provided in this work should be of broad significance to all chemical research that involves photon/matter interactions.

  19. Studying flow close to an interface by total internal reflection fluorescence cross-correlation spectroscopy: Quantitative data analysis

    Science.gov (United States)

    Schmitz, R.; Yordanov, S.; Butt, H. J.; Koynov, K.; Dünweg, B.

    2011-12-01

    Total internal reflection fluorescence cross-correlation spectroscopy (TIR-FCCS) has recently [S. Yordanov , Optics ExpressOPEXFF1094-408710.1364/OE.17.021149 17, 21149 (2009)] been established as an experimental method to probe hydrodynamic flows near surfaces, on length scales of tens of nanometers. Its main advantage is that fluorescence occurs only for tracer particles close to the surface, thus resulting in high sensitivity. However, the measured correlation functions provide only rather indirect information about the flow parameters of interest, such as the shear rate and the slip length. In the present paper, we show how to combine detailed and fairly realistic theoretical modeling of the phenomena by Brownian dynamics simulations with accurate measurements of the correlation functions, in order to establish a quantitative method to retrieve the flow properties from the experiments. First, Brownian dynamics is used to sample highly accurate correlation functions for a fixed set of model parameters. Second, these parameters are varied systematically by means of an importance-sampling Monte Carlo procedure in order to fit the experiments. This provides the optimum parameter values together with their statistical error bars. The approach is well suited for massively parallel computers, which allows us to do the data analysis within moderate computing times. The method is applied to flow near a hydrophilic surface, where the slip length is observed to be smaller than 10nm, and, within the limitations of the experiments and the model, indistinguishable from zero.

  20. Interaction of europium and nickel with calcite studied by Rutherford Backscattering Spectrometry and Time-Resolved Laser Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, A. [Agence Nationale pour la gestion des Déchets RAdioactifs, 1-7 rue J. Monnet, Parc de la Croix Blanche, 92298 Châtenay-Malabry Cedex (France); Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Pipon, Y., E-mail: pipon@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Institut Universitaire de Technologie (IUT) Lyon-1, Université Claude Bernard Lyon 1, 69 622 Villeurbanne Cedex (France); Toulhoat, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); CEA/DEN, Saclay, 91191 Gif sur Yvette (France); Lomenech, C. [Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Jordan, N. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); Moncoffre, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Barkleit, A. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); and others

    2014-08-01

    This study aims at elucidating the mechanisms regulating the interaction of Eu and Ni with calcite (CaCO{sub 3}). Calcite powders or single crystals (some mm sized) were put into contact with Eu or Ni solutions at concentrations ranging from 10{sup −3} to 10{sup −5} mol L{sup −1} for Eu and 10{sup −3} mol L{sup −1} for Ni. The sorption durations ranged from 1 week to 1 month. Rutherford Backscattering Spectrometry (RBS) well adapted to discriminate incorporation processes such as: (i) adsorption or co precipitation at the mineral surfaces or, (ii) incorporation into the mineral structure (through diffusion for instance), has been carried out. Moreover, using the fluorescence properties of europium, the results have been compared to those obtained by Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) on calcite powders. For the single crystals, complementary SEM observations of the mineral surfaces at low voltage were also performed. Results showed that Ni accumulates at the calcite surface whereas Eu is also incorporated at a greater depth. Eu seems therefore to be incorporated into two different states in calcite: (i) heterogeneous surface accumulation and (ii) incorporation at depth greater than 160 nm after 1 month of sorption. Ni was found to accumulate at the surface of calcite without incorporation.

  1. Local mobility in lipid domains of supported bilayers characterized by atomic force microscopy and fluorescence correlation spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, Daniel J.; Buranda, T. (University of New Mexico, Albuquerque, NM); Burns, Alan Richard

    2005-01-01

    Fluorescence correlation spectroscopy (FCS) is used to examine mobility of labeled probes at specific sites in supported bilayers consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid domains in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Those sites are mapped beforehand with simultaneous atomic force microscopy and submicron confocal fluorescence imaging, allowing characterization of probe partitioning between gel DPPC and disordered liquid DOPC domains with corresponding topography of domain structure. We thus examine the relative partitioning and mobility in gel and disordered liquid phases for headgroup- and tailgroup-labeled GM1 ganglioside probes and for headgroup- and tailgroup-labeled phospholipid probes. For the GM1 probes, large differences in mobility between fluid and gel domains are observed; whereas unexpected mobility is observed in submicron gel domains for the phospholipid probes. We attribute the latter to domain heterogeneities that could be induced by the probe. Furthermore, fits to the FCS data for the phospholipid probes in the DOPC fluid phase require two components (fast and slow). Although proximity to the glass substrate may be a factor, local distortion of the probe by the fluorophore could also be important. Overall, we observe nonideal aspects of phospholipid probe mobility and partitioning that may not be restricted to supported bilayers.

  2. Distribution of Fe atom density in a dc magnetron sputtering plasma source measured by laser-induced fluorescence imaging spectroscopy

    Science.gov (United States)

    Shibagaki, K.; Nafarizal, N.; Sasaki, K.; Toyoda, H.; Iwata, S.; Kato, T.; Tsunashima, S.; Sugai, H.

    2003-10-01

    Magnetron sputtering discharge is widely used as an efficient method for thin film fabrication. In order to achieve the optimized fabrication, understanding of the kinetics in plasmas is essential. In the present work, we measured the density distribution of sputtered Fe atoms using laser-induced fluorescence imaging spectroscopy. A dc magnetron plasma source with a Fe target was used. An area of 20 × 2 mm in front of the target was irradiated by a tunable laser beam having a planar shape. The picture of laser-induced fluorescence on the laser beam was taken using an ICCD camera. In this way, we obtained the two-dimensional image of the Fe atom density. As a result, it has been found that the Fe atom density observed at a distance of several centimeters from the target is higher than that adjacent to the target, when the Ar gas pressure was relatively high. It is suggested from this result that some gas-phase production processes of Fe atoms are available in the plasma. This work has been performed under the 21st Century COE Program by the Ministry of Education, Culture, Sports, Science and Technology in Japan.

  3. X-Ray Fluorescence Spectroscopy for Analysis of Explosive-Related Materials and Unknowns

    Science.gov (United States)

    2017-08-01

    instrument uses a 50 W X-ray tube with a Pd target and has a sample chamber with a six- sample turret. The maximum sample size is 44 mm in diameter by...absorbance of X-rays by the elements present, and the X-ray fluorescence following excitation from other X-rays produced by the sample . Qualitative data...CAN2 Big Approximately 7.6 g of weathered CAN, enough to fill a sample cup To investigate possible errors associated with small sample size

  4. Assessment of drinking water quality at the tap using fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Heibati, Masoumeh; Stedmon, Colin A; Stenroth, Karolina

    2017-01-01

    Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively......, relationships between DOM optical properties, microbial indicator organisms and trace elements were investigated for households connected to a biologically-stable drinking water distribution system. Across the network, humic-like fluorescence intensities showed limited variation (RSD = 3.5-4.4%), with half...

  5. Photo-induced processes in collagen-hypericin system revealed by fluorescence spectroscopy and multiphoton microscopy.

    Science.gov (United States)

    Hovhannisyan, V; Guo, H W; Hovhannisyan, A; Ghukasyan, V; Buryakina, T; Chen, Y F; Dong, C Y

    2014-05-01

    Collagen is the main structural protein and the key determinant of mechanical and functional properties of tissues and organs. Proper balance between synthesis and degradation of collagen molecules is critical for maintaining normal physiological functions. In addition, collagen influences tumor development and drug delivery, which makes it a potential cancer therapy target. Using second harmonic generation, two-photon excited fluorescence microscopy, and spectrofluorimetry, we show that the natural pigment hypericin induces photosensitized destruction of collagen-based tissues. We demonstrate that hypericin-mediated processes in collagen fibers are irreversible and may be used for the treatment of cancer and collagen-related disorders.

  6. Measurement of isotope shift of recycled uranium by laser induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Oba, Masaki; Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi

    1999-07-01

    Isotope shift of the recycled uranium atoms including the 236 U was measured by laser induced fluorescence method. Eight even levels at 2 eV and three odd levels at 4 eV were measured with isotope shifts among 238 U, 236 U and 235 U obtained. As for the measurement of the 4 eV levels, the Doppler free two photon absorption method was used, and the hyperfine structure of the 235 U was analyzed simultaneously. The isotope shift of 234 U was also observed in the three transition. (J.P.N.)

  7. Analysis of the substrate recognition state of TDP-43 to single-stranded DNA using fluorescence correlation spectroscopy

    Directory of Open Access Journals (Sweden)

    Akira Kitamura

    2018-07-01

    Full Text Available Normal function and abnormal aggregation of transactivation response (TAR DNA/RNA-binding protein 43 kDa (TDP-43 are directly associated with the lethal genetic diseases: cystic fibrosis, amyotrophic lateral sclerosis (ALS, and frontotemporal lobar degeneration (FTLD. The binding of TDP-43 to single-stranded DNA (ssDNA or RNA is involved in transcriptional repression, regulation of RNA splicing, and RNA stabilization. Equilibrium dissociation constants (Kd of TDP-43 and ssDNA or RNA have been determined using various methods; however, methods that can measure Kd with high sensitivity in a short time using a small amount of TDP-43 in solution would be advantageous. Here, in order to determine the Kd of TDP-43 and fluorescence-labeled ssDNA as well as the binding stoichiometry, we use fluorescence correlation spectroscopy (FCS, which detects the slowed diffusion of molecular interactions in solution with single-molecule sensitivity, in addition to electrophoretic mobility shift assay (EMSA. Using tandem affinity chromatography of TDP-43 dually tagged with glutathione-S-transferase and poly-histidine tags, highly purified protein was obtained. FCS successfully detected specific interaction between purified TDP-43 and TG ssDNA repeats, with a Kd in the nanomolar range. The Kd of the TDP-43 mutant was not different from the wild type, although mutant oligomers, which did not bind ssDNA, were observed. Analysis of the fluorescence brightness per dimerized TDP-43/ssDNA complex was used to evaluate their binding stoichiometry. The results suggest that an assay combining FCS and EMSA can precisely analyze ssDNA recognition mechanisms, and that FCS may be applied for the rapid and quantitative determination of the interaction strength between TDP-43 and ssDNA or RNA. These methods will aid in the elucidation of the substrate recognition mechanism of ALS- and FTLD-associated variants of TDP-43.

  8. A Geometric Dictionary Learning Based Approach for Fluorescence Spectroscopy Image Fusion

    Directory of Open Access Journals (Sweden)

    Zhiqin Zhu

    2017-02-01

    Full Text Available In recent years, sparse representation approaches have been integrated into multi-focus image fusion methods. The fused images of sparse-representation-based image fusion methods show great performance. Constructing an informative dictionary is a key step for sparsity-based image fusion method. In order to ensure sufficient number of useful bases for sparse representation in the process of informative dictionary construction, image patches from all source images are classified into different groups based on geometric similarities. The key information of each image-patch group is extracted by principle component analysis (PCA to build dictionary. According to the constructed dictionary, image patches are converted to sparse coefficients by simultaneous orthogonal matching pursuit (SOMP algorithm for representing the source multi-focus images. At last the sparse coefficients are fused by Max-L1 fusion rule and inverted to fused image. Due to the limitation of microscope, the fluorescence image cannot be fully focused. The proposed multi-focus image fusion solution is applied to fluorescence imaging area for generating all-in-focus images. The comparison experimentation results confirm the feasibility and effectiveness of the proposed multi-focus image fusion solution.

  9. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    Science.gov (United States)

    Hansen, Stephanie

    2017-10-01

    The burning core of an inertial confinement fusion (ICF) plasma at stagnation is surrounded by a shell of warm, dense matter whose properties are difficult both to model (due to a complex interplay of thermal, degeneracy, and strong coupling effects) and to diagnose (due to low emissivity and high opacity). We demonstrate a promising technique to study the warm dense shells of ICF plasmas based on the fluorescence emission of dopants or impurities in the shell material. This emission, which is driven by x-rays produced in the hot core, exhibits signature changes in response to compression and heating. High-resolution measurements of absorption and fluorescence features can refine our understanding of the electronic structure of material under high compression, improve our models of density-driven phenomena such as ionization potential depression and plasma polarization shifts, and help diagnose shell density, temperature, mass distribution, and residual motion in ICF plasmas at stagnation. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. This work was supported by the U.S. Department of Energy, Office of Science Early Career Research Program, Office of Fusion Energy Sciences under FWP-14-017426.

  10. Potential of fluorescence spectroscopy for the characterisation of maple syrup flavours.

    Science.gov (United States)

    Panneton, Bernard; Clément, Alain; Lagacé, Luc

    2013-10-01

    Maple syrup has high maket value. It is produced in North East America from the heat-evaporated sap of Acer saccharum Marshall. For marketing purposes, there is interest in defining its flavour profile in a consistent and repeatable manner. An experiment was undertaken to explore the potential of autofluorescence of maple syrup induced at 275 and 360 nm to characterise flavours. A mixed data factor analysis revealed two independent groups of variables. One represents early season woody and late season empyreumatic flavours. The other is related to off-flavour, confectionery and maple flavours. Maple and confectionery flavours are subtle, difficult to distinguish and opposed to off-flavour. There were clear relationships among the two groups and fluorescence profiles. For each of the five basic flavours, discriminant models based on partial least squares regressions were developed. For each sample of syrup, flavours combined to form flavour profiles, and the results from the five discriminant models were aggregated to reproduce these profiles. For excitation at 275 nm, the woody/off-flavour and confectionery/empyreumatic/maple flavour profiles were classified correctly 86 and 78% of the time (cross-validation) respectively. Induced autofluorescence spectra were shown to contain information related to maple syrup flavours. This fluorescence-flavour relationship is not considered quantitative yet, and further research avenues are proposed. © 2013 Society of Chemical Industry.

  11. Multi-elemental analysis of marine sediments of Sorsogon Bay using x-ray fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gonzales, Ralph Roly A.; Quirit, Leni L.; Rosales, Colleen Marciel F.; Pabroa, Preciosa Corazon B.; Sta Maria, Efren J.

    2011-01-01

    Metal composition and nutrient loadings of our bodies of water, when uncontrolled, may cause harmful bacterial contamination and pose threats in aquatic and human life. Toxic and trace element inputs in Sorsogon Bay sediments were determined using nuclear analytical techniques, more specifically, x-ray fluorescence spectrometry, in this study. Pre-treated marine sediment samples from Sorsogon Bay were homogenized using SPEX # 8000 mixer/mill and agate mortar and pestle, pelletized into 31-mm flat discs using SPEX 3630 X-Press and analyzed using PAN Analytical Epsilon 5 EDX X-ray Fluorescence Spectrometer with the emission and transmission method using silver and germanium secondary targets. Spectrum fitting performed using AXIL (Analysis of X-ray Spectra by Iterative Least-Squares Fitting), a subprogram in Quantitative X-ray Analysis System developed by the International Atomic Energy Agency and Quantitative Analysis of Environmental Samples program, was used for quantification of results. Results indicate generally moderate to high metal enrichment, specifically manganese, lead, cadmium, zinc and copper. Mercury and iron level enrichment are found to be low, marking an improvement from previous studies indicating high enrichment of these metals. (author)

  12. Standard test method for analysis of uranium and thorium in soils by energy dispersive X-Ray fluorescence spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers the energy dispersive X-ray fluorescence (EDXRF) spectrochemical analysis of trace levels of uranium and thorium in soils. Any sample matrix that differs from the general ground soil composition used for calibration (that is, fertilizer or a sample of mostly rock) would have to be calibrated separately to determine the effect of the different matrix composition. 1.2 The analysis is performed after an initial drying and grinding of the sample, and the results are reported on a dry basis. The sample preparation technique used incorporates into the sample any rocks and organic material present in the soil. This test method of sample preparation differs from other techniques that involve tumbling and sieving the sample. 1.3 Linear calibration is performed over a concentration range from 20 to 1000 μg per gram for uranium and thorium. 1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are for information only. 1.5 This standard...

  13. A Project-Based Biochemistry Laboratory Promoting the Understanding and Uses of Fluorescence Spectroscopy in the Study of Biomolecular Structures and Interactions

    Science.gov (United States)

    Briese, Nicholas; Jakubowsk, Henry V.

    2007-01-01

    A laboratory project for a first semester biochemistry course is described, which integrates the traditional classroom study of the structure and function of biomolecules with the laboratory study of these molecules using fluorescence spectroscopy. Students are assigned a specific question addressing the stability/function of lipids, proteins, or…

  14. Artificial neural networks as a multivariate calibration tool: modelling the Fe-Cr-Ni system in X-ray fluorescence spectroscopy

    NARCIS (Netherlands)

    Bos, A.; Bos, A.; Bos, M.; van der Linden, W.E.

    1993-01-01

    The performance of artificial neural networks (ANNs) for modeling the Cr---Ni---Fe system in quantitative x-ray fluorescence spectroscopy was compared with the classical Rasberry-Heinrich model and a previously published method applying the linear learning machine in combination with singular value

  15. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  16. Characterization of a Fe inclusion in beryllium-matrix using auger electron spectroscopy

    International Nuclear Information System (INIS)

    Arkusk, R.; Moreno, D.; Simca, F.; Yeheskel, O.; Utzmoni, U.

    1991-04-01

    The auger electron spectroscopy techniques was employed to investigate the nature of an inclusion that had been revealed by radiography in a beryllium body produced by the hot isostatic press technique. The investigation's are that the inclusion is composed of several different iron-beryllium intermetallic compounds (BeFe 3 , BeFe 5 , Be 7 Fe). The conclusion drawn is that iron metal impurity was imbedded in the Be powder and that interdiffusion under the process's conditions gave rise to the enlarged inclusion. (author)

  17. X-ray Fluorescence Spectroscopy: the Potential of Astrophysics-developed Techniques

    Science.gov (United States)

    Elvis, M.; Allen, B.; Hong, J.; Grindlay, J.; Kraft, R.; Binzel, R. P.; Masterton, R.

    2012-12-01

    X-ray fluorescence from the surface of airless bodies has been studied since the Apollo X-ray fluorescence experiment mapped parts of the lunar surface in 1971-1972. That experiment used a collimated proportional counter with a resolving power of ~1 and a beam size of ~1degree. Filters separated only Mg, Al and SI lines. We review progress in X-ray detectors and imaging for astrophysics and show how these advances enable much more powerful use of X-ray fluorescence for the study of airless bodies. Astrophysics X-ray instrumentation has developed enormously since 1972. Low noise, high quantum efficiency, X-ray CCDs have flown on ASCA, XMM-Newton, the Chandra X-ray Observatory, Swift and Suzaku, and are the workhorses of X-ray astronomy. They normally span 0.5 to ~8 keV with an energy resolution of ~100 eV. New developments in silicon based detectors, especially individual pixel addressable devices, such as CMOS detectors, can withstand many orders of magnitude more radiation than conventional CCDs before degradation. The capability of high read rates provides dynamic range and temporal resolution. Additionally, the rapid read rates minimize shot noise from thermal dark current and optical light. CMOS detectors can therefore run at warmer temperatures and with ultra-thin optical blocking filters. Thin OBFs mean near unity quantum efficiency below 1 keV, thus maximizing response at the C and O lines.such as CMOS detectors, promise advances. X-ray imaging has advanced similarly far. Two types of imager are now available: specular reflection and coded apertures. X-ray mirrors have been flown on the Einstein Observatory, XMM-Newton, Chandra and others. However, as X-ray reflection only occurs at small (~1degree) incidence angles, which then requires long focal lengths (meters), mirrors are not usually practical for planetary missions. Moreover the field of view of X-ray mirrors is comparable to the incident angle, so can only image relatively small regions. More useful

  18. Rare Earth Elements as Potential Biosignatures on Mars in SuperCam Time Resolved Laser Fluorescence Spectroscopy Data

    Science.gov (United States)

    Ollila, A.; Beyssac, O.; Sharma, S. K.; Misra, A. K.; Clegg, S. M.; Gauthier, M.; Wiens, R. C.; Maurice, S.; Gasnault, O.; Lanza, N.

    2017-12-01

    The rare earth elements (REE, La to Lu) are a group of elements with similar chemical properties that are generally present in geologic materials at trace concentrations. REEs may be concentrated via processes such as igneous fractional crystallization in accessory minerals, e.g. apatite, zircon, and titanite. Additionally, however, concentrations of REE may serve to identify regions of high astrobiological interest. For example, Fe-oxyhydroxide deposits in hydrothermal vent systems and biologically related manganese nodules may be enriched in REEs. REEs have not been measured in situ on Mars, therefore their prevalence and distribution on Mars is as yet unknown, except as observed in martian meteorites. SuperCam is a survey instrument that will analyze materials around the Mars 2020 rover using a variety of spectral techniques including laser-induced breakdown spectroscopy (LIBS), Raman, VIS-IR, and time-resolved laser fluorescence (TRLF) spectroscopy. Recently, the SuperCam Engineering Development Unit was tested at the Los Alamos National Laboratory for its capabilities to detect REEs in minerals using TRLF spectroscopy. While this instrument was not designed to precisely replicate the flight model, the spectral resolution and light transmission was sufficient to obtain TRLF spectra on a number of minerals demonstrating a variety of REE luminescent centers. These include apatite (Sm3+, Nd3+, Eu3+, Dy3+), fluorite (Ho3+, Sm3+, Dy3+, Nd3+), and zircon (Er3+, Pr3+, Nd3+). Future work includes expanding this suite to include minerals associated with biological activities, for example Mn-oxides (desert varnish and manganese nodules), hydrothermal Fe-oxides, and stromatolite-associated carbonates. In this way and in combination with its other techniques, SuperCam may direct the rover team to perform further analyses of similar samples by the in situ chemical and mineralogical suite of instruments, or aid in prioritization for sample return.

  19. In Situ Planetary Mineralogy Using Simultaneous Time Resolved Fluorescence and Raman Spectroscopy

    Science.gov (United States)

    Blacksberg, J.; Rossman , G.R.

    2011-01-01

    Micro-Raman spectroscopy is one of the primary methods of mineralogical analysis in the laboratory, and more recently in the field. Because of its versatility and ability to interrogate rocks in their natural form it is one of the front runners for the next generation of in situ instruments designed to explore adverse set of solar system bodies (e.g. Mars, Venus, the Moon, and other primitive bodies such as asteroids and the Martian moons Phobos and Deimos), as well as for pre-selection of rock and soil samples for potential cache and return missions.

  20. Photo-initiated dynamics and spectroscopy of the deprotonated Green Fluorescent Protein chromophore

    DEFF Research Database (Denmark)

    Bochenkova, Anastasia; Andersen, Lars Henrik

    2013-01-01

    . Knowledge of intrinsic properties of the GFP photoabsorbing molecular unit is a prerequisite in understanding the atomic-scale interactions that play a key role for the diverse functioning of these proteins. Here, we show how recent developments in action and photoelectron spectroscopy combined with state...... efficiently compete with each other in spite of their inherently different intrinsic timescales. The reason behind this is an efficient coupling between the nuclear and electronic motion in the photo-initiated dynamics, where the energy may be transferred from nuclei to electrons and from electrons to nuclei...

  1. Europium Uptake and Partitioning in Oat (Avena sativa) Roots as studied By Laser-Induced Fluorescence Spectroscopy and Confocal Microscopy Profiling Technique

    International Nuclear Information System (INIS)

    Fellows, Robert J.; Wang, Zheming; Ainsworth, Calvin C.

    2003-01-01

    The uptake of Eu3+ by elongating oat plant roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, as well as laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that the initial uptake of Eu(III) by oat root was most evident within the apical meristem of the root just proximal to the root cap. Distribution of assimilated Eu(III) within the roots differentiation and elongation zone was non-uniform. Higher concentrations were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root. The concentration of assimilated Eu3+ dropped sharply from the apical meristem to the differentiation and elongation zone and then gradually decreased as the distance from the root cap increased. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists a s inner-sphere mononuclear complexes inside the root. This work has also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal[Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides

  2. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  3. Optimizing Monocapillary Optics for Synchrotron X-ray Diffraction, Fluorescence Imaging, and Spectroscopy Applications

    International Nuclear Information System (INIS)

    Bilderback, Donald H.; Kazimirov, Alexander; Gillilan, Richard; Cornaby, Sterling; Woll, Arthur; Zha, Chang-Sheng; Huang Rong

    2007-01-01

    A number of synchrotron x-ray applications such as powder diffraction in diamond anvil cells, microbeam protein crystallography, x-ray fluorescence imaging, etc. can benefit from using hollow glass monocapillary optics to improve the flux per square micron on a sample. We currently draw glass tubing into the desired elliptical shape so that only one-bounce under total reflection conditions is needed to bring the x-ray beam to a focus at a 25 to 50 mm distance beyond the capillary tip. For modest focal spot sizes of 10 to 20 microns, we can increase the intensity per square micron by factors of 10 to 1000. We show some of the results obtained at CHESS and Hasylab with capillaries focusing 5 to 40 keV radiation, their properties, and how even better the experimental results could be if more ideal capillaries were fabricated in the future

  4. Collimated dual species oven source and its characterisation via spatially resolved fluorescence spectroscopy

    Science.gov (United States)

    Cooper, N.; Da Ros, E.; Nute, J.; Baldolini, D.; Jouve, P.; Hackermüller, L.; Langer, M.

    2018-03-01

    We describe the design, construction and characterisation of a collimated, dual-species oven source for generating intense beams of lithium and caesium in UHV environments. Our design produces full beam overlap for the two species. Using an aligned microtube array the FWHM of the output beam is restricted to  ˜75 milliradians, with an estimated axial brightness of 3.6× 1014 atoms s-1 sr-1 for Li and 7.4× 1015 atoms s-1 sr-1 for Cs. We measure the properties of the output beam using a spatially-resolved fluorescence technique, which allows for the extraction of additional information not accessible without spatial resolution.

  5. Modern X-ray spectroscopy 3. X-ray fluorescence holography

    International Nuclear Information System (INIS)

    Hayashi, Kouichi

    2008-01-01

    X-ray fluorescence holography (XFH) provides three dimensional atomic images around specified elements. The XFH uses atoms as a wave source or monitor of interference field within a crystal sample, and therefore it can record both intensity and phase of scattered X-rays. Its current performance makes it possible to apply to ultra thin film, impurity and quasicrystal. In this article, I show the theory including solutions for twin image problem, advanced measuring system, data processing for reconstruction of the atomic images and for obtaining accurate atomic positions, applications using resonant X-ray scattering and X-ray excited optical luminescence, and an example of XFH result on the local structure around copper in silicon steal. (author)

  6. Two-photon excited fluorescence spectroscopy and imaging of melanin in vitro and in vivo

    Science.gov (United States)

    Krasieva, Tatiana B.; Liu, Feng; Sun, Chung-Ho; Kong, Yu; Balu, Mihaela; Meyskens, Frank L.; Tromberg, Bruce J.

    2012-03-01

    The ability to detect early melanoma non-invasively would improve clinical outcome and reduce mortality. Recent advances in two-photon excited fluorescence (TPEF) in vivo microscopy offer a powerful tool in early malignant melanoma diagnostics. The goal of this work was to develop a TPEF optical index for measuring relative concentrations of eumelanin and pheomelanin since ex vivo studies show that changes in this ratio have been associated with malignant transformation. We acquired TPEF emission spectra (λex=1000 nm) of melanin from several specimens, including human hair, malignant melanoma cell lines, and normal melanocytes and keratinocytes in different skin layers (epidermis, papillary dermis) in five healthy volunteers in vivo. We found that the pheomelanin emission peaks at around 620 nm and is blue-shifted from the eumelanin with broad maximum at 640-680nm. We defined "optical melanin index" (OMI) as a ratio of fluorescence signal intensities measured at 645 nm and 615nm. The measured OMI for a melanoma cell line MNT-1 was 1.6+/-0.2. The MNT-46 and MNT-62 lines (Mc1R gene knockdown) showed an anticipated change in melanins production ratio and had OMI of 0.55+/-0.05 and 0.17+/-0.02, respectively, which strongly correlated with HPLC data obtained for these lines. Average OMI measured for basal cells layers (melanocytes and keratinocytes) in normal human skin type I, II-III (not tanned and tanned) in vivo was 0.5, 1.05 and 1.16 respectively. We could not dependably detect the presence of pheomelanin in highly pigmented skin type V-VI. These data suggest that a non-invasive TPEF index could potentially be used for rapid melanin ratio characterization both in vitro and in vivo, including pigmented lesions.

  7. Photophysics of three delocalized lipophilic cations in reverse micelles: A fluorescence spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dong-Wei [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Qi, Zu-De [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Ding, Xin-Liang; Li, Jia-Han; Jiang, Feng-Lei [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu, Yi, E-mail: prof.liuyi@263.net [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Kwong, Daniel W.J. [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Wong, Wai-Kwok, E-mail: wkwong@hkbu.edu.hk [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China)

    2013-02-15

    In this paper, aiming at the trans-membrane transport properties of the different DLCs related with the cytotoxicities, we have studied photophysics of DLCs in RMs. MTT assays indicated that DLC 1 were more cytotoxic than DLC 2 and 3. Steady-state absorption and fluorescence method have been used to characterize the binding model of three DLCs (1, 2, and 3) in RMs and bovine serum albumin (BSA). The progressive red-shift of compound 1 indicated that it can experience the hydrophilic and hydrophobic environment owing to the rigid structure, thus it can more easily cross the double membrane of cell than compounds 2 and 3. In conclusion, we simulated a model of compound 1 in RMs. The present study of F16 derivatives in microenvironment would provide some useful information to the cell membrane simulation and design of DLCs. - Graphical abstract: Aiming at the trans-membrane transport properties of the different DLCs related with the antitumor properties, MTT assay, steady-state absorption and fluorescence method have been used to characterize the binding model of three DLCs (1, 2, and 3) in reverse micelles (RMs) and bovine serum albumin (BSA). Highlights: Black-Right-Pointing-Pointer The drugs penetrating into the reverse micelles core were used to mimic the feature of drug trans-membrane transport. Black-Right-Pointing-Pointer Compound 1 was incorporated into the Stern Layer of reverse micelles, while compound 3 was not. Black-Right-Pointing-Pointer Reverse micelles would be used as a biomimic for drug designing and screening.

  8. Ultraviolet-Visible and Fluorescence Spectroscopy Techniques Are Important Diagnostic Tools during the Progression of Atherosclerosis: Diet Zinc Supplementation Retarded or Delayed Atherosclerosis

    Science.gov (United States)

    Abdelhalim, Mohamed Anwar K.; Moussa, Sherif A. Abdelmottaleb; AL-Mohy, Yanallah Hussain

    2013-01-01

    Background. In this study, we examined whether UV-visible and fluorescence spectroscopy techniques detect the progression of atherosclerosis in serum of rabbits fed on high-cholesterol diet (HCD) and HCD supplemented with zinc (HCD + Zn) compared with the control. Methods. The control rabbits group was fed on 100 g/day of normal diet. The HCD group was fed on Purina Certified Rabbit Chow supplemented with 1.0% cholesterol plus 1.0% olive oil (100 g/day) for the same period. The HCD + Zn group was fed on normal Purina Certified Rabbit Chow plus 1.0% cholesterol and 1.0% olive oil supplemented with 470 ppm Zn for the same feeding period. UV-visible and fluorescence spectroscopy and biochemistry in Rabbit's blood serum and blood hematology were measured in Rabbit's blood. Results. We found that the fluorescent peak of HCD shifted toward UV-visible wavelength compared with the control using fluorescent excitation of serum at 192 nm. In addition, they showed that supplementation of zinc (350 ppm) restored the fluorescent peak closely to the control. By using UV-visible spectroscopy approach, we found that the peak absorbance of HCD (about 280 nm) was higher than that of control and that zinc supplementation seemed to decrease the absorbance. Conclusions. This study demonstrates that ultraviolet-visible and fluorescence spectroscopy techniques can be applied as noninvasive techniques on a sample blood serum for diagnosing or detecting the progression of atherosclerosis. The Zn supplementation to rabbits fed on HCD delays or retards the progression of atherosclerosis. Inducing anemia in rabbits fed on HCD delays the progression of atherosclerosis. PMID:24350281

  9. Fourier Transform Infrared Spectroscopy to Quantify Collagen and Elastin in an In Vitro Model of Extracellular Matrix Degradation in Aorta

    Science.gov (United States)

    Cheheltani, Rabee; McGoverin, Cushla M.; Rao, Jayashree; Vorp, David A.; Kiani, Mohammad F.; Pleshko, N.

    2014-01-01

    Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues. PMID:24761431

  10. Fourier transform infrared spectroscopy to quantify collagen and elastin in an in vitro model of extracellular matrix degradation in aorta.

    Science.gov (United States)

    Cheheltani, Rabee; McGoverin, Cushla M; Rao, Jayashree; Vorp, David A; Kiani, Mohammad F; Pleshko, Nancy

    2014-06-21

    Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues.

  11. Double pulse laser induced breakdown spectroscopy: Experimental study of lead emission intensity dependence on the wavelengths and sample matrix

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli S, V; Martinez L, M A; Fernandez C, A J [Laboratorio de Espectroscopia Laser, Escuela de Quimica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, DC 1020 (Venezuela, Bolivarian Republic of); Gonzalez, J J; Mao, X L [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Russo, R.E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: RERusso@lbl.gov

    2009-02-15

    Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm. Two series of standard reference materials from the National Institute of Standards and Technology (NIST) and one series from the British Chemical Standards (BCS) were used for these experiments. Calibration curves for lead ablated from NIST 626-630 ('Zn{sub 95}Al{sub 4}Cu{sub 1}') provided higher sensitivity (slope) than those calibration curves produced from NIST 1737-1741 ('Zn{sub 99.5}Al{sub 0.5}') and with the series BCS 551-556 ('Cu{sub 87}Sn{sub 11}'). Similar trends between lead emission intensity (calibration curve sensitivities) and reported variations in plasma temperatures caused by the differing ionization potentials of the major and minor elements in these samples were established.

  12. Mechanical spectroscopy study on the Cu54Zr40Al6 amorphous matrix alloy at low temperature

    International Nuclear Information System (INIS)

    Marques, P.W.B.; Chaves, J.M.; Silva, P.S.; Florêncio, O.; Moreno-Gobbi, A.; Aliaga, L.C.R.; Botta, W.J.

    2015-01-01

    Highlights: • Cu 54 Zr 40 Al 6 alloy was characterized by mechanical spectroscopy at low temperature. • Flexural and ultrasonic methods showed peaks associated to rearrangement of clusters. • The peaks less stable were associated with annihilation of Zr or Cu clusters. • MHz range can be favors the formation of Cu an Al-centered icosahedral structures. • TEM images show an increase in the size and number of crystal in amorphous matrix. - Abstract: A mechanical spectroscopy study of Cu 54 Zr 40 Al 6 bulk metallic glasses composites was carried out in the kHz and MHz frequency ranges, by means of flexural and ultrasonic methods, respectively, in the temperature interval 150–300 K. In internal friction and attenuation curves at low temperature were observed peaks which were associated with distortions in the configuration of atomic clusters, which absorbed different quantities of energy due to short and medium order rearrangements. Changes within the clusters or atomic jumps between clusters occurring in the specimen induced the onset of polyamorphic peaks, since electronic interactions and bonding changed abruptly

  13. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Nitrogen Heterocycles (PANHs)

    Science.gov (United States)

    Mattioda, A. L.; Hudgins, D. M.; Bauschlicher, C. W.; Allamandola, L. J.; Biemesderfer, C. D.; Rosi, M.

    2002-01-01

    The mid-infrared spectra of the nitrogen-containing heterocyclic polycyclic aromatic compounds 1-azabenz[a]-anthracene; 2-azabenz[a]anthracene; 1-azachrysene; 2-azachrysene; 4-azachrysene; 2-azapyrene, and 7,8 benzoquinoline in their neutral and cation forms were investigated. The spectra of these species isolated in an argon matrix have been measured. Band frequencies and intensities were tabulated and these data compared with spectra computed using density functional theory at the B3LYP level. The overall agreement between experiment and theory is quite good, in keeping with earlier results on homonuclear polycyclic aromatic hydrocarbons. The differences between the spectral properties of nitrogen bearing aromatics and non-substituted, neutral polycyclic aromatic hydrocarbons will be discussed.

  14. Quantitative methods for compensation of matrix effects and self-absorption in Laser Induced Breakdown Spectroscopy signals of solids

    Science.gov (United States)

    Takahashi, Tomoko; Thornton, Blair

    2017-12-01

    This paper reviews methods to compensate for matrix effects and self-absorption during quantitative analysis of compositions of solids measured using Laser Induced Breakdown Spectroscopy (LIBS) and their applications to in-situ analysis. Methods to reduce matrix and self-absorption effects on calibration curves are first introduced. The conditions where calibration curves are applicable to quantification of compositions of solid samples and their limitations are discussed. While calibration-free LIBS (CF-LIBS), which corrects matrix effects theoretically based on the Boltzmann distribution law and Saha equation, has been applied in a number of studies, requirements need to be satisfied for the calculation of chemical compositions to be valid. Also, peaks of all elements contained in the target need to be detected, which is a bottleneck for in-situ analysis of unknown materials. Multivariate analysis techniques are gaining momentum in LIBS analysis. Among the available techniques, principal component regression (PCR) analysis and partial least squares (PLS) regression analysis, which can extract related information to compositions from all spectral data, are widely established methods and have been applied to various fields including in-situ applications in air and for planetary explorations. Artificial neural networks (ANNs), where non-linear effects can be modelled, have also been investigated as a quantitative method and their applications are introduced. The ability to make quantitative estimates based on LIBS signals is seen as a key element for the technique to gain wider acceptance as an analytical method, especially in in-situ applications. In order to accelerate this process, it is recommended that the accuracy should be described using common figures of merit which express the overall normalised accuracy, such as the normalised root mean square errors (NRMSEs), when comparing the accuracy obtained from different setups and analytical methods.

  15. WATSON: Detecting organic material in subsurface ice using deep-UV fluorescence and Raman spectroscopy

    Science.gov (United States)

    Eshelman, E.; Wanger, G.; Manatt, K.; Malaska, M.; Willis, M.; Abbey, W.; Doloboff, I.; Beegle, L. W.; DeFlores, L. P.; Priscu, J. C.; Lane, A. L.; Carrier, B. L.; Mellerowicz, B.; Kim, D.; Paulsen, G.; Zacny, K.; Bhartia, R.

    2017-12-01

    Future astrobiological missions to Europa and other ocean worlds may benefit from next-generation instrumentation capable of in situ organic and life detection in subsurface ice environments. WATSON (Wireline Analysis Tool for in Situ Observation of Northern ice sheets) is an instrument under development at NASA's Jet Propulsion Laboratory. WATSON contains high-TRL instrumentation developed for SHERLOC, the Mars 2020 deep-UV fluorescence and Raman spectrometer, including a 248.6 nm NeCu hollow cathode laser as an excitation source. In WATSON, these technologies provide spectroscopic capabilities highly sensitive to many organic compounds, including microbes, in an instrument package approximately 1.2 m long with a 101.6 mm diameter, designed to accommodate a 108 mm ice borehole. Interrogation into the ice wall with a laser allows for a non-destructive in situ measurement that preserves the spatial distribution of material within the ice. We report on a successful deployment of WATSON to Kangerlussuaq, Greenland, where the instrument was lowered to a 4.5 m depth in a hand-cored hole on the Kangerlussuaq sector of the Greenland ice sheet. Motorized stages within the instrument were used to raster a laser across cm-scale regions of the interior surface of the borehole, obtaining fluorescence spectral maps with a 200 µm spatial resolution and a spectral range from 265 nm to 440 nm. This region includes the UV emission bands of many aromatic compounds and microbes, and includes the water and ice Raman O-H stretching modes. We additionally report on experiments designed to inform an early-2018 deployment to Kangerlussuaq where WATSON will be incorporated into a Honeybee Robotics planetary deep drill, with a goal of drilling to a depth of 100 m and investigating the distribution of organic material within the ice sheet. These experiments include laboratory calibrations to determine the sensitivity to organic compounds embedded in ice at various depths, as well as

  16. Measurements of IO in the Tropical Marine Boundary Layer using Laser-Induced Fluorescence Spectroscopy

    Science.gov (United States)

    Walker, H.; Ingham, T.; Heard, D. E.

    2012-12-01

    Halogenated short-lived substances (VSLS) are emitted from the oceans by marine species such as macroalgae and phytoplankton and contribute to halogen loading in the troposphere and lower stratosphere. Transport of halogenated VSLS into the stratosphere occurs mainly in the tropics, where ascending warm air carries them aloft, and leads to catalytic depletion of stratospheric ozone on a global scale and formation of the Antarctic ozone hole. The tropical marine environment is therefore an important region in which to study the effects of these short-lived halogen species on ozone depletion. The SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project combines ship-borne, aircraft-based and ground-based measurements in and over the South China Sea and the Sulu Sea, and around the coast of Malaysian Borneo, to reduce uncertainties in the amount of halogenated VSLS reaching the stratosphere, the associated ozone depletion, and the effects of a changing climate on these processes. In this work we present measurements of IO radicals made onboard the German research vessel Sonne during SHIVA, between Singapore and Manila. IO is formed via photolysis of iodine-containing source gases (e.g. I2, CH3I) to produce I atoms, which react with ozone. It is therefore an important species to consider when assessing the impacts of halogen chemistry on ozone depletion. Measurements of IO were made over a two-week period by the University of Leeds Laser-Induced Fluorescence (LIF) instrument, which excites IO radicals at λ ~ 445 nm and detects the resultant fluorescence at λ ~ 512 nm. A suite of supporting gas- and aqueous-phase measurements were also made, including concentrations of halocarbons (e.g. CHBr3, CH3I), trace pollutant gases (e.g. CO, O3, NOx), and biological parameters (e.g. abundance and speciation of phytoplankton). Preliminary data analysis indicates that IO was detected above the instrumental limit of detection (0.3 pptv for a 30 minute averaging

  17. Atomic emission and atomic fluorescence spectroscopy in the direct current plasma

    International Nuclear Information System (INIS)

    Hendrick, M.S.

    1985-01-01

    The Direct Current Plasma (DCP) was investigated as a source for Atomic Emission (AE) and Atomic Fluorescence Spectrometry (AFS). The DCP was optimized for AE analyses using simplex optimization and Box-Behnken partial factorial experimental design, varying argon flows, and plasma position. Results were compared with a univariate search carried out in the region of the simplex optimum. Canonical analysis demonstrated that no true optimum exists for sensitivity, precision, or drift. A stationary ridge, where combinations of conditions gave comparable instrumental responses, was found. The DCP as an excitation source for AFS in a flame was used for diagnostic studies of the DCP. Moving the aerosol introduction tube behind the DCP with respect to the flame improved the characteristics of the DCP as a narrow line source, although self-absorption was observed at high concentrations of metal salt solutions in the DCP. Detection limits for Cd, Co, Cr, Cu, Fe, Mg, Mn, Zn, and Ni were in the low ng/mL region. Theoretical expressions for scatter correction with a two-line technique were derived, although no correction was necessary to achieve accurate results for standard reference materials

  18. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    Science.gov (United States)

    Hansen, S. B.; Harding, E. C.; Knapp, P. F.; Gomez, M. R.; Nagayama, T.; Bailey, J. E.

    2018-05-01

    The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. We show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated by the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 1024 e/cm3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.

  19. Elemental distribution in ascending aortic after radiotherapy and chemotherapy by Low Energy X-ray Fluorescence spectroscopy

    Science.gov (United States)

    Mantuano, A.; Mota, C. L.; Pickler, A.; Sena, G.; Braz, D.; Salata, C.; de Almeida, C. E.; Costa, F. N.; Barroso, R. C.

    2018-05-01

    Breast cancer (BC) is the most frequent cancer and the leading cause of cancer-related mortality in women. The treatment techniques for the BC include chemotherapy (CT) and/or radiotherapy (RT) and can modify elementary the cell matrix by calcificating tissues due to biological and morphological changes. Also, treatments for BC induce cardiotoxicity and it is important to understand the mechanisms involved in order to prevent this late effect in treated breast cancer patients. The high incidence of cardiovascular mortality in breast cancer patients is partially credited to increased intimal and medial calcifications of the aorta. The aim of this work is to investigate the distibution of low atomic number elements such as Magnesium (Mg), due to its importance for the cardiac metabolism; iron (Fe), since BC treatment may be associated with oxidative stress; and Sodium (Na), that is extremely related to the damage of endothelial cells. An optimal technique to observe these changes in aorta tissue is soft X-ray FLuorescence that can provide elemental maps of these important elements. The results performed by Low Energy X-ray Fluorescence LEXRF analyses showed that when the tissue is submitted to treatments with CT and/or RT, some normal structures become disorganized, and consequently the intensity of elemental compounds can be changed. All the experiments were carried out at the TwinMic beamline at Elettra Synchrotron facility using as animal model Wistar rats in order to evaluate the distribution of Na, Mg and Fe in aorta walls of Wistar rats, after BC treatment. Simultaneous acquisition of LEXRF and attenuation coefficient maps suggest that the combined chemotherapy and radiotherapy caused more damage to the aortic tissue as compared to radiation therapy alone. These findings add an in-depth understanding of elemental lack or excess in the tissue and contribute to locate these changes.

  20. Mutational definition of binding requirements of an hnRNP-like protein in Arabidopsis using fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leder, Verena [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Lummer, Martina [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Tegeler, Kathrin [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Humpert, Fabian [Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Lewinski, Martin [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Schüttpelz, Mark [Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Staiger, Dorothee, E-mail: dorothee.staiger@uni-bielefeld.de [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany)

    2014-10-10

    Highlights: • We use FCS to investigate binding site requirements for the hnRNP-like protein AtGRP7. • We identify three nucleotides critical for AtGRP7 binding to its own intron. • Mutation of the conserved R{sup 49} abolishes binding altogether. • The paralogue AtGRP8 binds to an overlapping motif with different sequence requirement. • The glycine-rich stretch of a plant hnRNP-like protein contributes to binding. - Abstract: Arabidopsis thaliana glycine-rich RNA binding protein 7 (AtGRP7) is part of a negative feedback loop through which it regulates alternative splicing and steady-state abundance of its pre-mRNA. Here we use fluorescence correlation spectroscopy to investigate the requirements for AtGRP7 binding to its intron using fluorescently-labelled synthetic oligonucleotides. By systematically introducing point mutations we identify three nucleotides that lead to an increased K{sub d} value when mutated and thus are critical for AtGRP7 binding. Simultaneous mutation of all three residues abrogates binding. The paralogue AtGRP8 binds to an overlapping motif but with a different sequence preference, in line with overlapping but not identical functions of this protein pair. Truncation of the glycine-rich domain reduces the binding affinity of AtGRP7, showing for the first time that the glycine-rich stretch of a plant hnRNP-like protein contributes to binding. Mutation of the conserved R{sup 49} that is crucial for AtGRP7 function in pathogen defence and splicing abolishes binding.

  1. PCR-free detection of genetically modified organisms using magnetic capture technology and fluorescence cross-correlation spectroscopy.

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhou

    2009-11-01

    Full Text Available The safety of genetically modified organisms (GMOs has attracted much attention recently. Polymerase chain reaction (PCR amplification is a common method used in the identification of GMOs. However, a major disadvantage of PCR is the potential amplification of non-target DNA, causing false-positive identification. Thus, there remains a need for a simple, reliable and ultrasensitive method to identify and quantify GMO in crops. This report is to introduce a magnetic bead-based PCR-free method for rapid detection of GMOs using dual-color fluorescence cross-correlation spectroscopy (FCCS. The cauliflower mosaic virus 35S (CaMV35S promoter commonly used in transgenic products was targeted. CaMV35S target was captured by a biotin-labeled nucleic acid probe and then purified using streptavidin-coated magnetic beads through biotin-streptavidin linkage. The purified target DNA fragment was hybridized with two nucleic acid probes labeled respectively by Rhodamine Green and Cy5 dyes. Finally, FCCS was used to detect and quantify the target DNA fragment through simultaneously detecting the fluorescence emissions from the two dyes. In our study, GMOs in genetically engineered soybeans and tomatoes were detected, using the magnetic bead-based PCR-free FCCS method. A detection limit of 50 pM GMOs target was achieved and PCR-free detection of GMOs from 5 microg genomic DNA with magnetic capture technology was accomplished. Also, the accuracy of GMO determination by the FCCS method is verified by spectrophotometry at 260 nm using PCR amplified target DNA fragment from GM tomato. The new method is rapid and effective as demonstrated in our experiments and can be easily extended to high-throughput and automatic screening format. We believe that the new magnetic bead-assisted FCCS detection technique will be a useful tool for PCR-free GMOs identification and other specific nucleic acids.

  2. Mutational definition of binding requirements of an hnRNP-like protein in Arabidopsis using fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Leder, Verena; Lummer, Martina; Tegeler, Kathrin; Humpert, Fabian; Lewinski, Martin; Schüttpelz, Mark; Staiger, Dorothee

    2014-01-01

    Highlights: • We use FCS to investigate binding site requirements for the hnRNP-like protein AtGRP7. • We identify three nucleotides critical for AtGRP7 binding to its own intron. • Mutation of the conserved R 49 abolishes binding altogether. • The paralogue AtGRP8 binds to an overlapping motif with different sequence requirement. • The glycine-rich stretch of a plant hnRNP-like protein contributes to binding. - Abstract: Arabidopsis thaliana glycine-rich RNA binding protein 7 (AtGRP7) is part of a negative feedback loop through which it regulates alternative splicing and steady-state abundance of its pre-mRNA. Here we use fluorescence correlation spectroscopy to investigate the requirements for AtGRP7 binding to its intron using fluorescently-labelled synthetic oligonucleotides. By systematically introducing point mutations we identify three nucleotides that lead to an increased K d value when mutated and thus are critical for AtGRP7 binding. Simultaneous mutation of all three residues abrogates binding. The paralogue AtGRP8 binds to an overlapping motif but with a different sequence preference, in line with overlapping but not identical functions of this protein pair. Truncation of the glycine-rich domain reduces the binding affinity of AtGRP7, showing for the first time that the glycine-rich stretch of a plant hnRNP-like protein contributes to binding. Mutation of the conserved R 49 that is crucial for AtGRP7 function in pathogen defence and splicing abolishes binding

  3. A study of the dynamics of PTEN proteins in living cells using in vivo fluorescence correlation spectroscopy

    Science.gov (United States)

    Du, Zhixue; Dong, Chaoqing; Ren, Jicun

    2017-06-01

    PTEN (phosphatase and tensin homolog on chromosome 10) is one of the most important tumor-suppressor proteins, which plays a key role in negative regulation of the PI3K/AKT pathway, and governs many cellular processes including growth, proliferation, survival and migration. The dynamics of PTEN proteins in single living cells is as yet unclear owing to a shortage of suitable in vivo approaches. Here, we report a single-molecule method for in vivo study of the dynamics of PTEN proteins in living cells using fluorescence correlation spectroscopy (FCS). First, we established a monoclonal H1299 stable cell line expressing enhanced green fluorescent protein (EGFP) and PTEN (EGFP-PTEN) fusion proteins; we then developed an in vivo FCS method to study the dynamics of EGFP-PTEN both in the nucleus and the cytoplasm. We investigated the diffusion behaviors of EGFP and EGFP-PTEN in solution, nucleus and cytosol, and observed that the motion of PTEN in living cells was restricted compared with EGFP. Finally, we investigated the protein dynamics in living cells under oxidative stress stimulation and a cellular ATP depletion treatment. Under oxidative stress stimulation, the EGFP-PTEN concentration increased in the nucleus, but slightly decreased in the cytoplasm. The diffusion coefficient and alpha value of EGFP-PTEN reduced significantly both in the nucleus and cytoplasm; the significantly decreased alpha parameter indicates a more restricted Brownian diffusion behavior. Under the cellular ATP depletion treatment, the concentration of EGFP-PTEN remained unchanged in the nucleus and decreased significantly in cytosol. The diffusion coefficient of EGFP-PTEN decreased significantly in cytosol, but showed no significant change in the nucleus; the alpha value decreased significantly in both the nucleus and cytoplasm. These results suggest that the concentration and mobility of PTEN in the nucleus and cytoplasm can be regulated by stimulation methods. Our approach provides a unique

  4. Fluorescence enhancement of samarium complex co-doped with terbium complex in a poly(methyl methacrylate) matrix

    International Nuclear Information System (INIS)

    Jiu Hongfang; Zhang Lixin; Liu Guode; Fan Tao

    2009-01-01

    The fluorescence property of Sm(DBM) 3 phen- (DBM-dibenzoylmethide, phen-1,10-phenanthroline) and Tb(DBM) 3 phen-co-doped poly(methyl methacrylate) (PMMA) was investigated. The excitation, emission spectra and fluorescence lifetime of the co-doped samples were examined. In the co-doped samples, the luminescence intensities of Sm 3+ enhance with an increase of the Tb(DBM) 3 phen content and with a decrease of the Sm(DBM) 3 phen content. The reason for the fluorescence enhancement effect in the co-doped polymer is the intermolecular energy transfer. To give a vivid picture for this co-doped system, a model for the fluorescence enhancement of Sm(DBM) 3 phen- and Tb(DBM) 3 phen-co-doped PMMA is presented

  5. Characterization of CDOM from urban waters in Northern-Northeastern China using excitation-emission matrix fluorescence and parallel factor analysis.

    Science.gov (United States)

    Zhao, Ying; Song, Kaishan; Li, Sijia; Ma, Jianhang; Wen, Zhidan

    2016-08-01

    Chromophoric dissolved organic matter (CDOM) plays an important role in aquatic systems, but high concentrations of organic materials are considered pollutants. The fluorescent component characteristics of CDOM in urban waters sampled from Northern and Northeastern China were examined by excitation-emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) to investigate the source and compositional changes of CDOM on both space and pollution levels. One humic-like (C1), one tryptophan-like component (C2), and one tyrosine-like component (C3) were identified by PARAFAC. Mean fluorescence intensities of the three CDOM components varied spatially and by pollution level in cities of Northern and Northeastern China during July-August, 2013 and 2014. Principal components analysis (PCA) was conducted to identify the relative distribution of all water samples. Cluster analysis (CA) was also used to categorize the samples into groups of similar pollution levels within a study area. Strong positive linear relationships were revealed between the CDOM absorption coefficients a(254) (R (2) = 0.89, p CDOM components can be applied to monitor water quality in real time compared to that of traditional approaches. These results demonstrate that EEM-PARAFAC is useful to evaluate the dynamics of CDOM fluorescent components in urban waters from Northern and Northeastern China and this method has potential applications for monitoring urban water quality in different regions with various hydrological conditions and pollution levels.

  6. Temperature-dependent loop formation kinetics in flexible peptides studied by time-resolved fluorescence spectroscopy

    Directory of Open Access Journals (Sweden)

    Harekrushna Sahoo

    2006-01-01

    Full Text Available Looping rates in short polypeptides can be determined by intramolecular fluorescence quenching of a 2,3-diazabicyclo[2.2.2]oct-2-ene-labeled asparagine (Dbo by tryptophan. By this methodology, the looping rates in glycine-serine peptides with the structure Trp-(Gly-Sern-Dbo-NH2 of different lengths (n = 0–10 were determined in dependence on temperature in D2O and the activation parameters were derived. In general, the looping rate increases with decreasing peptide length, but the shortest peptide (n=0 shows exceptional behavior because its looping rate is slower than that for the next longer ones (n=1,2. The activation energies increase from 17.5 kJ mol−1 for the longest peptide (n=10 to 20.5 kJ mol−1 for the shortest one (n=0, while the pre-exponential factors (log⁡(A/s−1 range from 10.20 to 11.38. The data are interpreted in terms of an interplay between internal friction (stiffness of the biopolymer backbone and steric hindrance effects and solvent friction (viscosity-limited diffusion. For the longest peptides, the activation energies resemble more and more the value expected for solvent viscous flow. Internal friction is most important for the shortest peptides, causing a negative curvature and a smaller than ideal slope (ca. –1.1 of the double-logarithmic plots of the looping rates versus the number of peptide chain segments (N. Interestingly, the corresponding plot for the pre-exponential factors (logA versus logN shows the ideal slope (–1.5. While the looping rates can be used to assess the flexibility of peptides in a global way, it is suggested that the activation energies provide a measure of the “thermodynamic” flexibility of a peptide, while the pre-exponential factors reflect the “dynamic” flexibility.

  7. Study of decorated archeological ceramics by micro X-ray fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Papadopoulou, D.; Sakalis, A.; Merousis, N.; Tsirliganis, N.C.

    2007-01-01

    Micro-X-ray fluorescence (μ-XRF) spectrometry is an analytical technique that is especially suitable for the study of archeological findings since it is non-destructive, rapid, universal, versatile and multi-elemental. In the present work a compact portable μ-XRF spectrometer was used to characterize decorated sherds of Neolithic pottery from Polyplatanos, North Greece. The sherds were divided into four decorative groups (crusted, classic Dimini, cream on red, and black on red) and the characterization was focused on the determination of certain major, minor and trace elements (Si, K, Ca, Ti, Cr, Mn, Fe, Ni) on the decorated surface and in the clay body. The aim of this characterization was to supplement and confirm archeological information regarding the origin of the artifacts and the manufacturing techniques used for their production. The most predominant chemical elements were determined, and representative ratios (Ca/K, Fe/Mn) were calculated and compared for each individual sample group. The crusted samples and the cream on red samples showed higher concentrations of Ca in the white-crusted surface in comparison with the clay body while Fe was the predominant element in the red decorated surface. The analysis of the samples of classic Dimini, revealed higher concentrations of Mn in the black painted surfaces and higher Ca content in the light-coloured clay bodies. Finally, most samples of the black on red group present high concentrations of Mn in their decoration surface. Zn and Ni were also detected in this group in contrast with the remaining groups

  8. Monitoring the process of purification of crude glycerol derived from biodiesel production: a method based on fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Keurison F.; Caires, Anderson R.L. [Universidade Federal da Grande Dourados, MS (Brazil). Grupo de Optica Aplicada; Oliveira, Samuel L. [Universidade Federal de Mato Grosso do Sul (UFMS), MS (Brazil). Grupo de Optica e Fotonica

    2011-07-01

    Full text. The use of biodiesel has increased worldwide. The biodiesel production on an industrial scale has been based on the transesterification of vegetable oils and fats with methanol in the presence of an alkaline catalyst. During the transesterification, one molecule of triglyceride reacts with three molecules of alcohol to produce glycerol and molecules of alkyl esters (biodiesel). As a result, an increase in biodiesel production also enhances the availability of glycerol on the market. However, crude glycerin has about 30% of impurities which are inherent to biodiesel production such as catalyst, alcohol and fatty acids. The present study evaluated the usefulness of the fluorescence spectroscopy as a tool to monitor the glycerol purification process. Glycerol samples were obtained from transesterification of soybean, canola, and sunflower oils in the presence of NaOH. After stirring time, the solutions were let to stand in separating funnels, then two phases were observed: one containing mainly biodiesel and other consisting of glycol. Then, the respective glycerol samples were collected, henceforth called G1. After that, it was added H2SO4 (20%) in the crude glycerol samples to reduce their pH to 4 in order to remove fatty acids. The solutions were stored for 24 hours in separating funnels. The glycerol (heavy phase), hereafter named G2, was then separated and filtered. To remove other impurities from G2 samples by means of ionic exchange columns, the samples were neutralized and diluted using Milli-Q water (G3 samples). Aliquots of 20 mL were then passed through cationic and anionic resins (G4 and G5 samples, respectively). Emission and excitation spectra of the G1-G5 samples as well as of the glycerol PA-ACS (reference) were recorded at room temperature using a spectrofluorimeter. The emission spectra were obtained setting the excitation at 325nm and monitoring the emission in the 330-800nm range. Fluorimetric maps were also achieved by pumping the

  9. Characterization of the AT180 epitope of phosphorylated Tau protein by a combined nuclear magnetic resonance and fluorescence spectroscopy approach

    International Nuclear Information System (INIS)

    Amniai, Laziza; Lippens, Guy; Landrieu, Isabelle

    2011-01-01

    Highlights: → pThr231 of the Tau protein is necessary for the binding of the AT180 antibody. → pSer235 of the Tau protein does not interfere with the AT180 recognition of pThr231. → Epitope mapping is efficiently achieved by combining NMR and FRET spectroscopy. -- Abstract: We present here the characterization of the epitope recognized by the AT180 monoclonal antibody currently used to define an Alzheimer's disease (AD)-related pathological form of the phosphorylated Tau protein. Some ambiguity remains as to the exact phospho-residue(s) recognized by this monoclonal: pThr231 or both pThr231 and pSer235. To answer this question, we have used a combination of nuclear magnetic resonance (NMR) and fluorescence spectroscopy to characterize in a qualitative and quantitative manner the phospho-residue(s) essential for the epitope recognition. Data from the first step of NMR experiments are used to map the residues bound by the antibodies, which were found to be limited to a few residues. A fluorophore is then chemically attached to a cystein residue introduced close-by the mapped epitope, at arginine 221, by mutagenesis of the recombinant protein. The second step of Foerster resonance energy transfer (FRET) between the AT180 antibody tryptophanes and the phospho-Tau protein fluorophore allows to calculate a dissociation constant Kd of 30 nM. We show that the sole pThr231 is necessary for the AT180 recognition of phospho-Tau and that phosphorylation of Ser235 does not interfere with the binding.

  10. Fluorescence Correlation Spectroscopy Using Octadecylrhodamine B as a Specific Micelle-Binding Fluorescent Tag, Light Scattering and Tapping Mode Atomic Force Microscopy Studies of Amphiphilic Water-Soluble Block Copolymer Micelles

    Czech Academy of Sciences Publication Activity Database

    Humpolíčková, J.; Procházka, K.; Hof, Martin; Tuzar, Zdeněk; Špírková, Milena

    2003-01-01

    Roč. 19, - (2003), s. 4111-4119 ISSN 0743-7463 R&D Projects: GA MŠk LN00A032; GA ČR GA203/01/0536; GA ČR GA203/01/0735 Institutional research plan: CEZ:AV0Z4050913; CEZ:AV0Z4040901 Keywords : fluorescence * spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.098, year: 2003

  11. Rapid quantification of polycyclic aromatic hydrocarbons in hydroxypropyl-{beta}-cyclodextrin (HPCD) soil extracts by synchronous fluorescence spectroscopy (SFS)

    Energy Technology Data Exchange (ETDEWEB)

    Guoxiong, Hua [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Broderick, John [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Semple, Kirk T [Department of Environmental Science, Faculty of Science and Technology, University of Lancaster, Lancaster LA1 4YQ (United Kingdom); Killham, Ken [School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom); Singleton, Ian [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2007-07-15

    Synchronous fluorescence spectroscopy (SFS) was directly applied to rapidly quantify selected polycyclic aromatic hydrocarbons (PAHs: benzo[a]pyrene and pyrene) in aqueous hydroxypropyl-{beta}-cyclodextrin (HPCD) soil extract solutions from a variety of aged contaminated soils containing four different PAHs. The method was optimized and validated. The results show that SFS can be used to analyse benzo[a]pyrene and pyrene in HPCD based soil extracts with high sensitivity and selectivity. The linear calibration ranges were 4.0 x 10{sup -6}-1.0 x 10{sup -3} mM for benzo[a]pyrene and 6.0 x 10{sup -6}-1.2 x 10{sup -3} mM for pyrene in 10 mM HPCD aqueous solution alone. The detection limits according to the error propagation theory for benzo[a]pyrene and pyrene were 3.9 x 10{sup -6} and 5.4 x 10{sup -6} mM, respectively. A good agreement between SFS and HPLC was reached for both determinations of PAHs in HPCD alone and in soil HPCD extracts. Hence, SFS is a potential means to simplify the present non-exhaustive hydroxypropyl-{beta}-cyclodextrin (HPCD)-based extraction technique for the evaluation of PAH bioavailability in soil. - SFS can be used to rapidly quantify selected PAHs in soil extracts and to simplify the non-exhaustive HPCD-based extraction technique for the evaluation of PAH bioavailability.

  12. Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

    Directory of Open Access Journals (Sweden)

    Pauline Maffre

    2014-11-01

    Full Text Available By using fluorescence correlation spectroscopy (FCS, we have studied the adsorption of human serum albumin (HSA onto Fe–Pt nanoparticles (NPs, 6 nm radius, CdSe/ZnS quantum dots (QDs, 5 nm radius and Au and Ag nanoclusters (1–4 nm radius, which are enshrouded by various water-solubilizing surface layers exposing different chemical functional groups (carboxyl, amino and both, thereby endowing the NPs with different surface charges. We have also measured the effects of modified surface functionalizations on the protein via succinylation and amination. A step-wise increase in hydrodynamic radius with protein concentration was always observed, revealing formation of protein monolayers coating the NPs, independent of their surface charge. The differences in the thickness of the protein corona were rationalized in terms of the different orientations in which HSA adsorbs onto the NPs. The midpoints of the binding transition, which quantifies the affinity of HSA toward the NP, were observed to differ by almost four orders of magnitude. These variations can be understood in terms of specific Coulombic interactions between the proteins and the NP surfaces.

  13. Real-time autocorrelator for fluorescence correlation spectroscopy based on graphical-processor-unit architecture: method, implementation, and comparative studies

    Science.gov (United States)

    Laracuente, Nicholas; Grossman, Carl

    2013-03-01

    We developed an algorithm and software to calculate autocorrelation functions from real-time photon-counting data using the fast, parallel capabilities of graphical processor units (GPUs). Recent developments in hardware and software have allowed for general purpose computing with inexpensive GPU hardware. These devices are more suited for emulating hardware autocorrelators than traditional CPU-based software applications by emphasizing parallel throughput over sequential speed. Incoming data are binned in a standard multi-tau scheme with configurable points-per-bin size and are mapped into a GPU memory pattern to reduce time-expensive memory access. Applications include dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS) experiments. We ran the software on a 64-core graphics pci card in a 3.2 GHz Intel i5 CPU based computer running Linux. FCS measurements were made on Alexa-546 and Texas Red dyes in a standard buffer (PBS). Software correlations were compared to hardware correlator measurements on the same signals. Supported by HHMI and Swarthmore College

  14. Synchronous front-face fluorescence spectroscopy for authentication of the adulteration of edible vegetable oil with refined used frying oil.

    Science.gov (United States)

    Tan, Jin; Li, Rong; Jiang, Zi-Tao; Tang, Shu-Hua; Wang, Ying; Shi, Meng; Xiao, Yi-Qian; Jia, Bin; Lu, Tian-Xiang; Wang, Hao

    2017-02-15

    Synchronous front-face fluorescence spectroscopy has been developed for the discrimination of used frying oil (UFO) from edible vegetable oil (EVO), the estimation of the using time of UFO, and the determination of the adulteration of EVO with UFO. Both the heating time of laboratory prepared UFO and the adulteration of EVO with UFO could be determined by partial least squares regression (PLSR). To simulate the EVO adulteration with UFO, for each kind of oil, fifty adulterated samples at the adulterant amounts range of 1-50% were prepared. PLSR was then adopted to build the model and both full (leave-one-out) cross-validation and external validation were performed to evaluate the predictive ability. Under the optimum condition, the plots of observed versus predicted values exhibited high linearity (R(2)>0.96). The root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP) were both lower than 3%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Rapid quantification of polycyclic aromatic hydrocarbons in hydroxypropyl-β-cyclodextrin (HPCD) soil extracts by synchronous fluorescence spectroscopy (SFS)

    International Nuclear Information System (INIS)

    Hua Guoxiong; Broderick, John; Semple, Kirk T.; Killham, Ken; Singleton, Ian

    2007-01-01

    Synchronous fluorescence spectroscopy (SFS) was directly applied to rapidly quantify selected polycyclic aromatic hydrocarbons (PAHs: benzo[a]pyrene and pyrene) in aqueous hydroxypropyl-β-cyclodextrin (HPCD) soil extract solutions from a variety of aged contaminated soils containing four different PAHs. The method was optimized and validated. The results show that SFS can be used to analyse benzo[a]pyrene and pyrene in HPCD based soil extracts with high sensitivity and selectivity. The linear calibration ranges were 4.0 x 10 -6 -1.0 x 10 -3 mM for benzo[a]pyrene and 6.0 x 10 -6 -1.2 x 10 -3 mM for pyrene in 10 mM HPCD aqueous solution alone. The detection limits according to the error propagation theory for benzo[a]pyrene and pyrene were 3.9 x 10 -6 and 5.4 x 10 -6 mM, respectively. A good agreement between SFS and HPLC was reached for both determinations of PAHs in HPCD alone and in soil HPCD extracts. Hence, SFS is a potential means to simplify the present non-exhaustive hydroxypropyl-β-cyclodextrin (HPCD)-based extraction technique for the evaluation of PAH bioavailability in soil. - SFS can be used to rapidly quantify selected PAHs in soil extracts and to simplify the non-exhaustive HPCD-based extraction technique for the evaluation of PAH bioavailability

  16. Probing Temperature- and pH-Dependent Binding between Quantum Dots and Bovine Serum Albumin by Fluorescence Correlation Spectroscopy

    Directory of Open Access Journals (Sweden)

    Zonghua Wang

    2017-04-01

    Full Text Available Luminescent quantum dots (QDs with unique optical properties have potential applications in bio-imaging. The interaction between QDs and bio-molecules is important to the biological effect of QDs in vivo. In this paper, we have employed fluorescence correlation spectroscopy (FCS to probe the temperature- and pH-dependent interactions between CdSe QDs with carboxyl (QDs-COOH and bovine serum albumin (BSA in buffer solutions. The results have shown that microscopic dissociation constant K′D is in the range of (1.5 ± 0.2 × 10−5 to (8.6 ± 0.1 × 10−7 M, the Hill coefficient n is from 0.4 to 2.3, and the protein corona thickness is from 3.0 to 9.4 nm. Variable-temperature measurements have shown both negative values of ∆H and ∆S for BSA adsorption on QDs-COOH, while pH has a profound effect on the adsorption. Additional, FCS measurement QDs-COOH and proteins in whole mice serum and plasma samples has also been conducted. Finally, simulation results have shown four favored QD binding sites in BSA.

  17. A combined fluorescence spectroscopy, confocal and 2-photon microscopy approach to re-evaluate the properties of sphingolipid domains.

    Science.gov (United States)

    Pinto, Sandra N; Fernandes, Fábio; Fedorov, Alexander; Futerman, Anthony H; Silva, Liana C; Prieto, Manuel

    2013-09-01

    The aim of this study is to provide further insight about the interplay between important signaling lipids and to characterize the properties of the lipid domains formed by those lipids in membranes containing distinct composition. To this end, we have used a combination of fluorescence spectroscopy, confocal and two-photon microscopy and a stepwise approach to re-evaluate the biophysical properties of sphingolipid domains, particularly lipid rafts and ceramide (Cer)-platforms. By using this strategy we were able to show that, in binary mixtures, sphingolipids (Cer and sphingomyelin, SM) form more tightly packed gel domains than those formed by phospholipids with similar acyl chain length. In more complex lipid mixtures, the interaction between the different lipids is intricate and is strongly dictated by the Cer-to-Chol ratio. The results show that in quaternary phospholipid/SM/Chol/Cer mixtures, Cer forms gel domains that become less packed as Chol is increased. Moreover, the extent of gel phase formation is strongly reduced in these mixtures, even though Cer molar fraction is increased. These results suggest that in biological membranes, lipid domains such as rafts and ceramide platforms, might display distinctive biophysical properties depending on the local lipid composition at the site of the membrane where they are formed, further highlighting the potential role of membrane biophysical properties as an underlying mechanism for mediating specific biological processes. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  19. A new on-axis micro-spectrophotometer for combining Raman, fluorescence and UV/Vis absorption spectroscopy with macromolecular crystallography at the Swiss Light Source.

    Science.gov (United States)

    Pompidor, Guillaume; Dworkowski, Florian S N; Thominet, Vincent; Schulze-Briese, Clemens; Fuchs, Martin R

    2013-09-01

    The combination of X-ray diffraction experiments with optical methods such as Raman, UV/Vis absorption and fluorescence spectroscopy greatly enhances and complements the specificity of the obtained information. The upgraded version of the in situ on-axis micro-spectrophotometer, MS2, at the macromolecular crystallography beamline X10SA of the Swiss Light Source is presented. The instrument newly supports Raman and resonance Raman spectroscopy, in addition to the previously available UV/Vis absorption and fluorescence modes. With the recent upgrades of the spectral bandwidth, instrument stability, detection efficiency and control software, the application range of the instrument and its ease of operation were greatly improved. Its on-axis geometry with collinear X-ray and optical axes to ensure optimal control of the overlap of sample volumes probed by each technique is still unique amongst comparable facilities worldwide and the instrument has now been in general user operation for over two years.

  20. A new on-axis micro-spectrophotometer for combining Raman, fluorescence and UV/Vis absorption spectroscopy with macromolecular crystallography at the Swiss Light Source

    Science.gov (United States)

    Pompidor, Guillaume; Dworkowski, Florian S. N.; Thominet, Vincent; Schulze-Briese, Clemens; Fuchs, Martin R.

    2013-01-01

    The combination of X-ray diffraction experiments with optical methods such as Raman, UV/Vis absorption and fluorescence spectroscopy greatly enhances and complements the specificity of the obtained information. The upgraded version of the in situ on-axis micro-spectrophotometer, MS2, at the macromolecular crystallography beamline X10SA of the Swiss Light Source is presented. The instrument newly supports Raman and resonance Raman spectroscopy, in addition to the previously available UV/Vis absorption and fluorescence modes. With the recent upgrades of the spectral bandwidth, instrument stability, detection efficiency and control software, the application range of the instrument and its ease of operation were greatly improved. Its on-axis geometry with collinear X-ray and optical axes to ensure optimal control of the overlap of sample volumes probed by each technique is still unique amongst comparable facilities worldwide and the instrument has now been in general user operation for over two years. PMID:23955041

  1. Equilibrium constants in aqueous lanthanide and actinide chemistry from time-resolved fluorescence spectroscopy: The role of ground and excited state reactions

    International Nuclear Information System (INIS)

    Billard, I.; Luetzenkirchen, K.

    2003-01-01

    Equilibrium constants for aqueous reactions between lanthanide or actinide ions and (in-) organic ligands contain important information for various radiochemical problems, such as nuclear reprocessing or the migration of radioelements in the geosphere. We study the conditions required to determine equilibrium constants by time-resolved fluorescence spectroscopy measurements. Based on a simulation study it is shown that the possibility to determine equilibrium constants depends upon the reaction rates in the photoexcited states of the lanthanide or actinide ions. (orig.)

  2. Mineral to matrix ratio determines biomaterial and biomechanical properties of rat femur--application of Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Takata, Shinjiro; Yonezu, Hiroshi; Shibata, Akira; Enishi, Tetsuya; Sato, Nori; Takahashi, Mitsuhiko; Nakao, Shigetaka; Komatsu, Koji; Yasui, Natsuo

    2011-08-01

    We studied the changes of biomaterial and biomechanical properties of the rat femur during development. Thirty male Wistar rats were allocated to 6 groups: aged 6 weeks (n=5), 9 weeks (n=5), 12 weeks (n=5), 15 weeks (n=5), 24 weeks (n=5), and 36 weeks (n=5). The mineral to matrix ratio (M/M ratio) of rat femur by Fourier transform infrared spectroscopy was 0.97 ± 0.10 at the age of 6 weeks, and reached the maximum of 1.52 ± 0.17 at the age of 36 weeks. Total bone mineral density (BMD) by peripheral quantitative computed tomography of the femoral shaft aged 6 weeks was 479.1 ± 58.7 mg/cm(3), and reached the maximum of 1022.2 ± 42.3 mg/cm(3) at the age of 36 weeks. The ultimate load to failure of the femur of the rat aged 6 weeks by the three-point bending test was 29.6 ± 6.1 N. At the age of 36 weeks, the ultimate load to failure of the rat femur increased to the maximum of 283.5 ± 14.7 N. The results showed that the M/M ratio increased with development as total BMD and bone strength increased. The results suggest that the M/M ratio is one of the determinants of the biomaterial and biomechanical properties of bone.

  3. Characterization of dissolved organic matter in a coral reef ecosystem subjected to anthropogenic pressures (La Réunion Island, Indian Ocean) using multi-dimensional fluorescence spectroscopy.

    Science.gov (United States)

    Tedetti, Marc; Cuet, Pascale; Guigue, Catherine; Goutx, Madeleine

    2011-05-01

    La Saline fringing reef is the most important coral reef complex of La Réunion Island (southwestern Indian Ocean; 21°07'S, 55°32'E). This ecosystem is subjected to anthropogenic pressures through river inputs and submarine groundwater discharge (SGD). The goal of this study was to characterize the pool of fluorescent dissolved organic matter (FDOM) in different water bodies of La Saline fringing reef ecosystem using excitation-emission matrix (EEM) spectrofluorometry. From EEMs, we identified the different fluorophores by the peak picking technique and determined two fluorescence indices issued from the literature: the humification index (HIX) and the biological index (BIX). The main known fluorophores were present within the sample set: humic-like A, humic-like C, marine humic-like M, tryptophan-like T1 and T2, and tyrosine-like B1 and B2. In some samples, unknown fluorophores ("U") were also detected. The surface oceanic waters located beyond the reef front displayed a typical oligotrophic marine signature, with a dominance of autochthonous/biological material (presence of peaks: T1>B1>A>T2>M>C; HIX: 0.9±0.4; BIX: 2.3±1.1). In the reef waters, the autochthonous/biological fingerprint also dominated even though the content in humic substances was higher (same relative distribution of peaks; HIX: 1.6±0.6; BIX: 1.0±0.1). Sedimentary and volcanic SGD showed very different patterns with a strong terrestrial source for the former (A>T1>C>B1 and A>C>B1; HIX: 9.8±2.0; BIX: 0.8±0.0) and a weak terrestrial source for the latter (A>B1>U3>B2>C and A>U4>C; HIX: 2.4±0.3; BIX: 0.9±0.0). In the Hermitage River, both humic substances and protein-like material were abundant (T1>A>U5>B1>C>B2; HIX: 2.3; BIX: 1.4). We provide evidences for the presence of anthropogenic DOM in some of these water bodies. Some oceanic samples (presence of peaks U1 and U2) were likely contaminated by oil-derived PAHs from ships navigating around the reef front, whereas the Hermitage River was

  4. Synthesis, crystal structure and spectral characteristics of highly fluorescent chalcone-based coumarin in solution and in polymer matrix

    Czech Academy of Sciences Publication Activity Database

    Ghouili, A.; Dušek, Michal; Petříček, Václav; Ben Ayed, T.; Ben Hassen, R.

    2014-01-01

    Roč. 75, č. 2 (2014), s. 188-193 ISSN 0022-3697 Grant - others:AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : coumarin chalcone * fluorescence * structure determination Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.853, year: 2014

  5. Seasonal characterization of CDOM for lakes in semiarid regions of Northeast China using excitation-emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC)

    Science.gov (United States)

    Zhao, Ying; Song, Kaishan; Wen, Zhidan; Li, Lin; Zang, Shuying; Shao, Tiantian; Li, Sijia; Du, Jia

    2016-03-01

    The seasonal characteristics of fluorescent components in chromophoric dissolved organic matter (CDOM) for lakes in the semiarid region of Northeast China were examined by excitation-emission matrix (EEM) spectra and parallel factor analysis (PARAFAC). Two humic-like (C1 and C2) and protein-like (C3 and C4) components were identified using PARAFAC. The average fluorescence intensity of the four components differed under seasonal variation from June and August 2013 to February and April 2014. Components 1 and 2 exhibited a strong linear correlation (R2 = 0.628). Significantly positive linear relationships between CDOM absorption coefficients a(254) (R2 = 0.72, 0.46, p DOC). However, almost no obvious correlation was found between salinity and EEM-PARAFAC-extracted components except for C3 (R2 = 0.469). Results from this investigation demonstrate that the EEM-PARAFAC technique can be used to evaluate the seasonal dynamics of CDOM fluorescent components for inland waters in the semiarid regions of Northeast China, and to quantify CDOM components for other waters with similar environmental conditions.

  6. Surface characterization of selected polymer thin films by total-reflection x-ray fluorescence spectroscopy and x-ray reflectivity

    International Nuclear Information System (INIS)

    Innis, Vallerie Ann A.

    2006-01-01

    Development of available x-ray characterizations tools for grazing incidence techniques was done to be able to probe nano-size thin films. Alignment of a Philips x-ray powder diffractometer was improved to let it perform as an x-ray reflectometer. X-ray reflectometry was coupled with total-reflection x-ray fluorescence spectroscopy. Evaluation of the performance of this grazing incidence techniques was done by preparing polymer thin films of carboxymethylcellulose, carrageenan and polyvinylpyrrolidone (PVP). The thickness of the films were varied by varying the process parameters such as concentration, spin speed and spin time. Angle-dispersive total-reflection x-ray fluorescence spectroscopy profiles of three films showed film formation only in carrageenan and PVP. For both carrageenan and PVP, an increase in concentration yielded a corresponding increase in intensity of the fluorescent or scattered peaks. XRR profiles of carrageenan thin films yielded a mean value for the critical angle close to quartz substrate. Thickness measurements of the prepared carrageenan thin films showed that concentration was the main determinant for final film thickness over the other process parameters. Sulfur fluorescent intensity derived from the TXRF measurement showed a linear relationship with the measured thickness by XRR. For PVP, measured critical angle is lower than quartz. Poor adhesion of the polymer onto the substrate yielded a limited number of thickness measurements made from the XRR profiles. (Author)

  7. Measurement of spatially resolved gas-phase plasma temperatures by optical emission and laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Davis, G.P.; Gottscho, R.A.

    1983-01-01

    Knowledge of the energy distributions of particles in glow discharges is crucial to the understanding and modeling of plasma reactors used in microelectronic manufacturing. Reaction rates, available product channels, and transport phenomena all depend upon the partitioning of energy in the discharge. Because of the nonequilibrium nature of glow discharges, however, the distribution of energy among different species and among different degrees of freedom cannot be characterized simply by one temperature. The extent to which different temperatures are needed for each degree of freedom and for each species is not known completely. How plasma operating conditions affect these energy distributions is also an unanswered question. We have investigated the temperatures of radicals, ions, and neutrals in CCl 4 , CCl 4 /N 2 (2%), and N 2 discharges. In the CCl 4 systems, we probed the CCl rotational and vibrational energy distributions by laser-induced fluorescence spectroscopy. The rotational distribution always appeared to be thermal but under identical operating conditions was found to be roughly-equal400 K colder than the vibrational distribution. The rotational temperature at any point in the discharge was strongly dependent upon both applied power and surface temperature. Thermal gradients as large as 10 2 K mm -1 were observed near electrode surfaces but the bulk plasmas were isothermal. When 2% N 2 was added to a CCl 4 discharge, N 2 second positive emission was observed and used to estimate the N 2 rotational temperature. The results suggest that emission from molecular actinometers can be used to measure plasma temperatures, providing such measurements are not made in close proximity to surfaces

  8. Chromophoric dissolved organic matter (CDOM) variability in Barataria Basin using excitation-emission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC).

    Science.gov (United States)

    Singh, Shatrughan; D'Sa, Eurico J; Swenson, Erick M

    2010-07-15

    Chromophoric dissolved organic matter (CDOM) variability in Barataria Basin, Louisiana, USA,was examined by excitation emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC). CDOM optical properties of absorption and fluorescence at 355nm along an axial transect (36 stations) during March, April, and May 2008 showed an increasing trend from the marine end member to the upper basin with mean CDOM absorption of 11.06 + or - 5.01, 10.05 + or - 4.23, 11.67 + or - 6.03 (m(-)(1)) and fluorescence 0.80 + or - 0.37, 0.78 + or - 0.39, 0.75 + or - 0.51 (RU), respectively. PARAFAC analysis identified two terrestrial humic-like (component 1 and 2), one non-humic like (component 3), and one soil derived humic acid like (component 4) components. The spatial variation of the components showed an increasing trend from station 1 (near the mouth of basin) to station 36 (end member of bay; upper basin). Deviations from this increasing trend were observed at a bayou channel with very high chlorophyll-a concentrations especially for component 3 in May 2008 that suggested autochthonous production of CDOM. The variability of components with salinity indicated conservative mixing along the middle part of the transect. Component 1 and 4 were found to be relatively constant, while components 2 and 3 revealed an inverse relationship for the sampling period. Total organic carbon showed increasing trend for each of the components. An increase in humification and a decrease in fluorescence indices along the transect indicated an increase in terrestrial derived organic matter and reduced microbial activity from lower to upper basin. The use of these indices along with PARAFAC results improved dissolved organic matter characterization in the Barataria Basin. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Evaluation of portable Raman spectroscopy and handheld X-ray fluorescence analysis (hXRF) for the direct analysis of glyptics

    Science.gov (United States)

    Lauwers, D.; Candeias, A.; Coccato, A.; Mirao, J.; Moens, L.; Vandenabeele, P.

    2016-03-01

    In archaeometry, the advantages of a combined use of Raman spectroscopy and X-ray fluorescence spectroscopy are extensively discussed for applications such as the analysis of paintings, manuscripts, pottery, etc. Here, we demonstrate for the first time the advantage of using both techniques for analysing glyptics. These engraved gemstones or glass materials were originally used as stamps, to identify the owner, for instance on letters, but also on wine vessels. For this research, a set of 64 glyptics (42 Roman glass specimens and 22 modern ones), belonging to the collection of the museum 'Quinta das Cruzes' in Funchal (Madeira, Portugal), was analysed with portable Raman spectroscopy and handheld X-ray fluorescence (hXRF). These techniques were also used to confirm the gemological identification of these precious objects and can give extra information about the glass composition. Raman spectroscopy identifies the molecular composition as well as on the crystalline phases present. On the other hand, hXRF results show that the antique Roman glass samples are characterised with low Pb and Sn levels and that the modern specimens can be discriminated in two groups: lead-based and non-lead-based ones.

  10. spectroscopy

    African Journals Online (AJOL)

    Aghomotsegin

    2015-10-14

    Oct 14, 2015 ... characterized by using phenotypic, API and Fourier transform infrared (FTIR) spectroscopy methods. One hundred and fifty-seven (157) strains were isolated from 13 cheese samples, and identification test was performed for 83 strains. At the end of the study, a total of 22 Lactococcus sp., 36 Enterecoccus ...

  11. Helium clusters as cold, liquid matrix for the laser spectroscopy of silver atoms, silver clusters and C60 fullerenes

    International Nuclear Information System (INIS)

    Hoffmann, K.

    1999-01-01

    One of the main obstacles in the study of gas phase metal clusters is their high temperature. Even cooling in a seeded beam is only of limited used, since the condensation continuously releases energy into the system. As a consequence, spectroscopic studies of free metal clusters typically yield broad structures, which are interpreted as plasma resonances of a free electron gas. An experiment on ionic sodium clusters has shown that low temperatures lead to a narrowing of the absorption bands and the appearance of additional structure, that can not be explained within the free electron model. Thus the need for cold clusters is evident. In principle the deposition of metal clusters into inert matrices eliminates the temperature problem but it can also inflict strong changes on the electronic spectra. Droplets of liquid helium serve as a much more gentle matrix that avoids many of the above problems. In this thesis the new technique of helium droplet spectroscopy is presented as a tool for the study of extremely cold metal clusters. Clusters of silver up to a mass greater than 7000 amu have been produced by pickup of single atoms by a beam of helium droplets. The droplets are formed in a supersonic expansion. The cluster's binding energy is removed by evaporative cooling and the system remains at 0.4 K. The doped droplets are probed by laser spectroscopy with a depletion technique or resonant two photon ionization. We were able to measure the first UV absorption spectrum of metal atoms (silver) inside helium droplets. Another experiment shows that a small fraction of the captured silver atoms resides on the surface of the droplet like alkali atoms. In a two photon process previously unobserved s- and d-Rydberg states of the free silver atom (20 left angle n left angle 80) were excited. The silver atoms, initially embedded in the helium droplets, are found to move to the surface and desorb when excited to the broadened 5p level. This is the first result showing laser

  12. Reviews in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2010-01-01

    This volume serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence spectroscopy. It summarizes the year's progress in fluorescence and its applications as well as includes authoritative analytical reviews.

  13. Estimation of different source contributions to sediment organic matter in an agricultural-forested watershed using end member mixing analyses based on stable isotope ratios and fluorescence spectroscopy.

    Science.gov (United States)

    Derrien, Morgane; Kim, Min-Seob; Ock, Giyoung; Hong, Seongjin; Cho, Jinwoo; Shin, Kyung-Hoon; Hur, Jin

    2018-03-15

    The two popular source tracing tools of stable isotope ratios (δ 13 C and δ 15 N) and fluorescence spectroscopy were used to estimate the relative source contributions to sediment organic matter (SeOM) at five different river sites in an agricultural-forested watershed (Soyang Lake watershed), and their capabilities for the source assignment were compared. Bulk sediments were used for the stable isotopes, while alkaline extractable organic matter (AEOM) from sediments was used to obtain fluorescent indices for SeOM. Several source discrimination indices were fully compiled for a range of the SeOM sources distributed in the catchments of the watershed, which included soils, forest leaves, crop (C3 and C4) and riparian plants, periphyton, and organic fertilizers. The relative source contributions to the river sediment samples were estimated via end member mixing analysis (EMMA) based on several selected discrimination indices. The EMMA based on the isotopes demonstrated that all sediments were characterized by a medium to a high contribution of periphyton ranging from ~30% to 70% except for one site heavily affected by forest and agricultural fields with relatively high contributions of terrestrial materials. The EMMA based on fluorescence parameters, however, did not show similar results with low contributions from forest leaf and periphyton. The characteristics of the studied watershed were more consistent with the source contributions determined by the isotope ratios. The discrepancy in the EMMA capability for source assignments between the two analytical tools can be explained by the limited analytical window of fluorescence spectroscopy for non-fluorescent dissolved organic matter (FDOM) and the inability of AEOM to represent original bulk particulate organic matter (POM). Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT

    Science.gov (United States)

    van Zaane, F.; Middelburg, T. A.; de Bruijn, H. S.; van der Ploeg-van den Heuvel, A.; de Haas, E. R. M.; Sterenborg, H. J. C. M.; Neumann, H. A. M.; Robinson, D. J.

    2009-06-01

    Introduction: The rate of PpIX fluorescence photobleaching is routinely used as a dose metric for ALA-PDT. Diffuse reflection spectroscopy is often used to account for variations in tissue optical properties at the photosensitizer excitation and emission bands. It can be used to quantify changes in vascular parameters, such as blood volume fraction and saturation, and can aid understanding of tissue response to PDT. The volume and(/or) depth over which these signals are acquired are critical. The aim of this study is to use quantitative reflectance spectroscopy (DPS) to correct fluorescence for changes in tissue optical properties and monitor PDT. Materials & Methods: ALA was topically applied to hairless mice skin and the incubated spot was treated with PDT according to fractionated illumination schemes. DPS measurements of vascular parameters and optical properties were performed directly before and after illumination. Both the differential signal, delivery-and-collection-fiber signal and the collection fiber signal, which all probe different measurement volumes, are analyzed. Results & Conclusions: Analysis of DPS measurements shows that at the depth where most fluorescence originates, there is almost no blood present. During PDT vascular parameters at this depth stay constant. In more oxygenated layers of the tissue, the optical properties do change during PDT, suggesting that only a small part of PpIX fluorescence originates from the interesting depths where vascular response occurs. Correcting fluorescence emission spectra for optical changes at specific depths and not for the total of changes in a larger volume, as is usually done now, can improve PpIX photobleaching based treatment monitoring.

  15. Absorption and fluorescence spectroscopy of 3-hydroxy-3-phenyl-1-o-carboxyphenyltriazene and its copper (II), nickel (II) and zinc (II) complexes: a novel fluorescence sensor

    International Nuclear Information System (INIS)

    Ressalan, S.; Iyer, C.S.P.

    2005-01-01

    Absorption and fluorescence spectroscopic properties of 3-hydroxy-3-phenyl-1-o-carboxyphenyltriazene (HT) are studied. The mechanism of photo-induced electron transfer (PET) followed by energy transfer process of the ligand and the Cu (II), Ni (II) and Zn (II) metal complexes have been investigated. The excited state photo induced intramolecular hydrogen transfer from N-OH to triazene 1-nitrogen atom is explained. The effect of pH, solvent and concentration on the absorption and fluorescence of the ligand is studied and it has been found that the absorption and fluorescence of HT is highly pH, solvent and concentration dependent. Participation of the N-OH proton of HT in the solvent assisted O to N-proton transfer has also been proposed. The fluorescence band shift and changes in intensity is modulated by protonation and complexation with metal ions. This fluorophore can thus be used as a pH dependent and M (n+1)+ /M n+ redox on/off switchable molecular sensor

  16. Determination of the major constituents in fruit of Arctium lappa L. by matrix solid-phase dispersion extraction coupled with HPLC separation and fluorescence detection.

    Science.gov (United States)

    Liu, He; Zhang, Yupu; Sun, Yantao; Wang, Xue; Zhai, Yujuan; Sun, Ye; Sun, Shuo; Yu, Aimin; Zhang, Hanqi; Wang, Yinghua

    2010-10-15

    The arctiin and arctigenin in the fruit of Arctium lappa L. were extracted by matrix solid-phase dispersion (MSPD) and determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The experimental conditions for the MSPD were optimized. Silica gel was selected as dispersion adsorbent and methanol as elution solvent. The calibration curve showed good relationship (r>0.9998) in the concentration range of 0.010-5.0μgmL(-1) for arctiin and 0.025-7.5μgmL(-1) for arctigenin. The recoveries were between 74.4% and 100%. The proposed method consumed less sample, time and solvent compared with conventional methods, including ultrasonic and Soxhlet extraction. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. A new on-axis micro-spectrophotometer for combining Raman, fluorescence and UV/Vis absorption spectroscopy with macromolecular crystallography at the Swiss Light Source

    International Nuclear Information System (INIS)

    Pompidor, Guillaume; Dworkowski, Florian S. N.; Thominet, Vincent; Schulze-Briese, Clemens; Fuchs, Martin R.

    2013-01-01

    The new version MS2 of the in situ on-axis micro-spectrophotometer at the macromolecular crystallography beamline X10SA of the Swiss Light Source supports the concurrent acquisition of Raman, resonance Raman, fluorescence and UV/Vis absorption spectra along with diffraction data. The combination of X-ray diffraction experiments with optical methods such as Raman, UV/Vis absorption and fluorescence spectroscopy greatly enhances and complements the specificity of the obtained information. The upgraded version of the in situ on-axis micro-spectrophotometer, MS2, at the macromolecular crystallography beamline X10SA of the Swiss Light Source is presented. The instrument newly supports Raman and resonance Raman spectroscopy, in addition to the previously available UV/Vis absorption and fluorescence modes. With the recent upgrades of the spectral bandwidth, instrument stability, detection efficiency and control software, the application range of the instrument and its ease of operation were greatly improved. Its on-axis geometry with collinear X-ray and optical axes to ensure optimal control of the overlap of sample volumes probed by each technique is still unique amongst comparable facilities worldwide and the instrument has now been in general user operation for over two years

  18. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations

    Science.gov (United States)

    Najbauer, Eszter E.; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2018-01-01

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, 6 conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-live of (3.7±0.5)·103 s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser induced conversions revealed that the excitation of the stretching overtone of both the side-chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations. PMID:26201050

  19. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    Bonn, M; Ueba, H; Wolf, M

    2005-01-01

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  20. Molecular spectroscopy

    International Nuclear Information System (INIS)

    Kokh, Eh.; Zonntag, B.

    1981-01-01

    The latest investigation results on molecular spectroscopy with application of synchrotron radiation in the region of vacuum ultraviolet are generalized. Some results on investigation of excited, superexcited and ionized molecule states with the use of adsorption spectroscopy, photoelectron spectroscopy, by fluorescent and mass-spectrometric methods are considered [ru

  1. MEMBRANE MOBILITY AND MICRODOMAIN LOCALIZATION OF THE DOPAMINE TRANSPORTER STUDIED BY CONFOCAL FLUORESCENCE CORRELATION SPECTROSCOPY (FCS) AND FRAP

    DEFF Research Database (Denmark)

    Adkins, Erica; (Vægter), Christian Bjerggaard; van Deurs, Bo

    FCS measurements in transiently transfected N2A neuroblastoma cells were impaired by photobleachning suggesting immobilization of the transporter in the membrane. This was confirmed by the use of fluorescence recovery after photobleaching (FRAP), which showed clear recovery of YFP-DAT fluorescence...

  2. New Approaches in Soil Organic Matter Fluorescence; A Solid Phase Fluorescence Approach

    Science.gov (United States)

    Bowman, M. M.; Sanclements, M.; McKnight, D. M.

    2017-12-01

    Fluorescence spectroscopy is a well-established technique to investigate the composition of organic matter in aquatic systems and is increasingly applied to soil organic matter (SOM). Current methods require that SOM be extracted into a liquid prior to analysis by fluorescence spectroscopy. Soil extractions introduce an additional layer of complexity as the composition of the organic matter dissolved into solution varies based upon the selected extractant. Water is one of the most commonly used extractant, but only extracts the water-soluble fraction of the SOM with the insoluble soil organic matter fluorescence remaining in the soil matrix. We propose the use of solid phase fluorescence on whole soils as a potential tool to look at the composition of organic matter without the extraction bias and gain a more complete understand of the potential for fluorescence as a tool in terrestrial studies. To date, the limited applications of solid phase fluorescence have ranged from food and agriculture to pharmaceutical with no clearly defined methods and limitations available. We are aware of no other studies that use solid phase fluorescence and thus no clear methods to look at SOM across a diverse set of soil types and ecosystems. With this new approach to fluorescence spectroscopy there are new challenges, such as blank correction, inner filter effect corrections, and sample preparation. This work outlines a novel method for analyzing soil organic matter using solid phase fluorescence across a wide range of soils collected from the National Ecological Observatory Network (NEON) eco-domains. This method has shown that organic matter content in soils must be diluted to 2% to reduce backscattering and oversaturation of the detector in forested soils. In mineral horizons (A) there is observed quenching of the humic-like organic matter, which is likely a result of organo-mineral complexation. Finally, we present preliminary comparisons between solid and liquid phase

  3. Detection of Copper (II) and Cadmium (II) binding to dissolved organic matter from macrophyte decomposition by fluorescence excitation-emission matrix spectra combined with parallel factor analysis

    International Nuclear Information System (INIS)

    Yuan, Dong-hai; Guo, Xu-jing; Wen, Li; He, Lian-sheng; Wang, Jing-gang; Li, Jun-qi

    2015-01-01

    Fluorescence excitation-emission matrix (EEM) spectra coupled with parallel factor analysis (PARAFAC) was used to characterize dissolved organic matter (DOM) derived from macrophyte decomposition, and to study its complexation with Cu (II) and Cd (II). Both the protein-like and the humic-like components showed a marked quenching effect by Cu (II). Negligible quenching effects were found for Cd (II) by components 1, 5 and 6. The stability constants and the fraction of the binding fluorophores for humic-like components and Cu (II) can be influenced by macrophyte decomposition of various weight gradients in aquatic plants. Macrophyte decomposition within the scope of the appropriate aquatic phytomass can maximize the stability constant of DOM-metal complexes. A large amount of organic matter was introduced into the aquatic environment by macrophyte decomposition, suggesting that the potential risk of DOM as a carrier of heavy metal contamination in macrophytic lakes should not be ignored. - Highlights: • Macrophyte decomposition increases fluorescent DOM components in the upper sediment. • Protein-like components are quenched or enhanced by adding Cu (II) and Cd (II). • Macrophyte decomposition DOM can impact the affinity of Cu (II) and Cd (II). • The log K M and f values showed a marked change due to macrophyte decomposition. • Macrophyte decomposition can maximize the stability constant of DOM-Cu (II) complexes. - Macrophyte decomposition DOM can influence on the binding affinity of metal ions in macrophytic lakes

  4. Heterogeneous adsorption behavior of landfill leachate on granular activated carbon revealed by fluorescence excitation emission matrix (EEM)-parallel factor analysis (PARAFAC).

    Science.gov (United States)

    Lee, Sonmin; Hur, Jin

    2016-04-01

    Heterogeneous adsorption behavior of landfill leachate on granular activated carbon (GAC) was investigated by fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC). The equilibrium adsorption of two leachates on GAC was well described by simple Langmuir and Freundlich isotherm models. More nonlinear isotherm and a slower adsorption rate were found for the leachate with the higher values of specific UV absorbance and humification index, suggesting that the leachate containing more aromatic content and condensed structures might have less accessible sites of GAC surface and a lower degree of diffusive adsorption. Such differences in the adsorption behavior were found even within the bulk leachate as revealed by the dissimilarity in the isotherm and kinetic model parameters between two identified PARAFAC components. For both leachates, terrestrial humic-like fluorescence (C1) component, which is likely associated with relatively large sized and condensed aromatic structures, exhibited a higher isotherm nonlinearity and a slower kinetic rate for GAC adsorption than microbial humic-like (C2) component. Our results were consistent with size exclusion effects, a well-known GAC adsorption mechanism. This study demonstrated the promising benefit of using EEM-PARAFAC for GAC adsorption processes of landfill leachate through fast monitoring of the influent and treated leachate, which can provide valuable information on optimizing treatment processes and predicting further environmental impacts of the treated effluent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Characterizing chromophoric dissolved organic matter in Lake Tianmuhu and its catchment basin using excitation-emission matrix fluorescence and parallel factor analysis.

    Science.gov (United States)

    Zhang, Yunlin; Yin, Yan; Feng, Longqing; Zhu, Guangwei; Shi, Zhiqiang; Liu, Xiaohan; Zhang, Yuanzhi

    2011-10-15

    Chromophoric dissolved organic matter (CDOM) is an important optically active substance that transports nutrients, heavy metals, and other pollutants from terrestrial to aquatic systems and is used as a measure of water quality. To investigate how the source and composition of CDOM changes in both space and time, we used chemical, spectroscopic, and fluorescence analyses to characterize CDOM in Lake Tianmuhu (a drinking water source) and its catchment in China. Parallel factor analysis (PARAFAC) identified three individual fluorophore moieties that were attributed to humic-like and protein-like materials in 224 water samples collected between December 2008 and September 2009. The upstream rivers contained significantly higher concentrations of CDOM than did the lake water (a(350) of 4.27±2.51 and 2.32±0.59 m(-1), respectively), indicating that the rivers carried a substantial load of organic matter to the lake. Of the three main rivers that flow into Lake Tianmuhu, the Pingqiao River brought in the most CDOM from the catchment to the lake. CDOM absorption and the microbial and terrestrial humic-like components, but not the protein-like component, were significantly higher in the wet season than in other seasons, indicating that the frequency of rainfall and runoff could significantly impact the quantity and quality of CDOM collected from the catchment. The different relationships between the maximum fluorescence intensities of the three PARAFAC components, CDOM absorption, and chemical oxygen demand (COD) concentration in riverine and lake water indicated the difference in the composition of CDOM between Lake Tianmuhu and the rivers that feed it. This study demonstrates the utility of combining excitation-emission matrix fluorescence and PARAFAC to study CDOM dynamics in inland waters. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Self-organising maps and correlation analysis as a tool to explore patterns in excitation-emission matrix data sets and to discriminate dissolved organic matter fluorescence components.

    Science.gov (United States)

    Ejarque-Gonzalez, Elisabet; Butturini, Andrea

    2014-01-01

    Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

  7. Independent components analysis coupled with 3D-front-face fluorescence spectroscopy to study the interaction between plastic food packaging and olive oil.

    Science.gov (United States)

    Kassouf, Amine; El Rakwe, Maria; Chebib, Hanna; Ducruet, Violette; Rutledge, Douglas N; Maalouly, Jacqueline

    2014-08-11

    Olive oil is one of the most valued sources of fats in the Mediterranean diet. Its storage was generally done using glass or metallic packaging materials. Nowadays, plastic packaging has gained worldwide spread for the storage of olive oil. However, plastics are not inert and interaction phenomena may occur between packaging materials and olive oil. In this study, extra virgin olive oil samples were submitted to accelerated interaction conditions, in contact with polypropylene (PP) and polylactide (PLA) plastic packaging materials. 3D-front-face fluorescence spectroscopy, being a simple, fast and non destructive analytical technique, was used to study this interaction. Independent components analysis (ICA) was used to analyze raw 3D-front-face fluorescence spectra of olive oil. ICA was able to highlight a probable effect of a migration of substances with antioxidant activity. The signals extracted by ICA corresponded to natural olive oil fluorophores (tocopherols and polyphenols) as well as newly formed ones which were tentatively identified as fluorescent oxidation products. Based on the extracted fluorescent signals, olive oil in contact with plastics had slower aging rates in comparison with reference oils. Peroxide and free acidity values validated the results obtained by ICA, related to olive oil oxidation rates. Sorbed olive oil in plastic was also quantified given that this sorption could induce a swelling of the polymer thus promoting migration. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Design and development of a LabVIEW-based LED-induced fluorescence spectroscopy system with applications in non-destructive quality assessment of agricultural products

    International Nuclear Information System (INIS)

    Abbasi, Hamed; Nazeri, Majid; Mireei, Seyed Ahmad

    2016-01-01

    Over the past several years, the demand for high quality agricultural products has been remarkably increased. Thus, it is important to use non-destructive methods for product quality monitoring. LED-induced fluorescence spectroscopy has proved its potential for nondestructive detection of some defects in agricultural products, such as tissue browning and bruising. Due to such defects, changes in the polyphenol and chlorophyll contents occur which can be considered as the visible marks of decreasing fruit quality. In the present work, a fluorescence spectrometer (spectrofluorometer) controlled by LabVIEW software was designed and developed. In this spectrometer, a consumer-grade webcam was used as an imaging sensor. The spectrometer was able to measure the fluorescence spectra directly from the fruit and vegetable surface in the desired regions. To do so, the spectrometer was equipped with a suitable fiber-optic probe. The hardware solution was based on data acquisition working on the USB platform and controlled by the application running on the PC. In this system, light emitting diodes with different wavelengths were used as the excitation sources for inducing fluorescence spectra of some famous fruits and vegetables. (paper)

  9. Characterization of Roman glass tesserae from the Coriglia excavation site (Italy) via energy-dispersive X-ray fluorescence spectrometry and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Donais, Mary Kate; Sparks, Andrew; Redente, Monica [Saint Anselm College, Department of Chemistry, Manchester, NH (United States); Pevenage, Jolien van; Moens, Luc; Vincze, Laszlo [Ghent University, Department of Analytical Chemistry, Ghent (Belgium); George, David B. [Saint Anselm College, Department of Classics, Manchester, NH (United States); Vandenabeele, Peter [Ghent University, Department of Archaeology, Ghent (Belgium)

    2016-12-15

    The combined use of handheld energy-dispersive X-ray fluorescence spectrometry, Raman spectroscopy, and micro-energy-dispersive X-ray fluorescence spectrometry permitted the characterization of Roman glass tesserae excavation from the Coriglia (Italy) archeological site. Analyses of ten different glass colors were conducted as spot analyses on intact samples and as both spot analyses and line scans on select cross-sectioned samples. The elemental and molecular information gained from these spectral measurements allowed for the qualitative chemical characterization of the bulk glass, decolorants, opacifiers, and coloring agents. The use of an antimony opacifier in many of the samples supports the late Imperial phasing as determined through numismatic, fresco, ceramics, and architectural evidence. And dealinization of the exterior glass layers caused by the burial environment was confirmed. (orig.)

  10. Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

    KAUST Repository

    Hoffman, A. S.; Debefve, L. M.; Bendjeriou-Sedjerari, Anissa; Ould-Chikh, Samy; Bare, Simon R.; Basset, Jean-Marie; Gates, B. C.

    2016-01-01

    X-ray absorption spectroscopy is an element-specific technique for probing the local atomic-scale environment around an absorber atom. It is widely used to investigate the structures of liquids and solids, being especially valuable for characterization of solid-supported catalysts. Reported cell designs are limited in capabilities—to fluorescence or transmission and to static or flowing atmospheres, or to vacuum. Our goal was to design a robust and widely applicable cell for catalyst characterizations under all these conditions—to allow tracking of changes during genesis and during operation, both under vacuum and in reactive atmospheres. Herein, we report the design of such a cell and a demonstration of its operation both with a sample under dynamic vacuum and in the presence of gases flowing at temperatures up to 300 °C, showing data obtained with both fluorescence and transmission detection. The cell allows more flexibility in catalyst characterization than any reported.

  11. Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

    KAUST Repository

    Hoffman, A. S.

    2016-07-26

    X-ray absorption spectroscop