WorldWideScience

Sample records for internal reflection fluorescence

  1. Total Internal Reflection Fluorescence Quantification of Receptor Pharmacology

    Directory of Open Access Journals (Sweden)

    Ye Fang

    2015-04-01

    Full Text Available Total internal reflection fluorescence (TIRF microscopy has been widely used as a single molecule imaging technique to study various fundamental aspects of cell biology, owing to its ability to selectively excite a very thin fluorescent volume immediately above the substrate on which the cells are grown. However, TIRF microscopy has found little use in high content screening due to its complexity in instrumental setup and experimental procedures. Inspired by the recent demonstration of label-free evanescent wave biosensors for cell phenotypic profiling and drug screening with high throughput, we had hypothesized and demonstrated that TIRF imaging is also amenable to receptor pharmacology profiling. This paper reviews key considerations and recent applications of TIRF imaging for pharmacology profiling.

  2. Alignment and calibration of total internal reflection fluorescence microscopy systems.

    Science.gov (United States)

    Toomre, Derek

    2012-04-01

    Live cell fluorescent microscopy is important in elucidating dynamic cellular processes such as cell signaling, membrane trafficking, and cytoskeleton remodeling. Often, transient intermediate states are revealed only when imaged and quantitated at the single-molecule, vesicle, or organelle level. Such insight depends on the spatiotemporal resolution and sensitivity of a given microscopy method. Confocal microscopes optically section the cell and improve image contrast and axial resolution (>600 nm) compared with conventional epifluorescence microscopes. Another approach, which can selectively excite fluorophores in an even thinner optical plane (microscopy (TIRFM). The key principle of TIRFM is that a thin, exponentially decaying, evanescent field of excitation can be generated at the interface of two mediums of different refractive index (RI) (e.g., the glass coverslip and the biological specimen); as such, TIRFM is ill-suited to deep imaging of cells or tissue. However, for processes near the lower cell cortex, the sensitivity of TIRFM is exquisite. The recent availability of a very high numerical-aperture (NA) objective lens (>1.45) and turnkey TIRFM systems by all the major microscopy manufacturers has made TIRFM increasingly accessible and attractive to biologists, especially when performed in a quantitative manner and complemented with orthogonal genetic and molecular manipulations. This protocol describes the procedure for alignment and calibration of TIRFM systems using standard cellular samples. The goal is to correctly collimate and align the TIRF illuminator vis-à-vis the downstream optics. For illustration, a 488-nm laser and green fluorescent protein (GFP) filter cube are used.

  3. Single-Molecule Fluorescence Studies of Membrane Transporters Using Total Internal Reflection Microscopy.

    Science.gov (United States)

    Goudsmits, Joris M H; van Oijen, Antoine M; Slotboom, Dirk J

    2017-01-01

    Cells are delineated by a lipid bilayer that physically separates the inside from the outer environment. Most polar, charged, or large molecules require proteins to reduce the energetic barrier for passage across the membrane and to achieve transport rates that are relevant for life. Here, we describe techniques to visualize the functioning of membrane transport proteins with fluorescent probes at the single-molecule level. First, we explain how to produce membrane-reconstituted transporters with fluorescent labels. Next, we detail the construction of a microfluidic flow cell to image immobilized proteoliposomes on a total internal reflection fluorescence microscope. We conclude by describing the methods that are needed to analyze fluorescence movies and obtain useful single-molecule data. © 2017 Elsevier Inc. All rights reserved.

  4. Microplate-compatible total internal reflection fluorescence microscopy for receptor pharmacology

    Science.gov (United States)

    Chen, Minghan; Zaytseva, Natalya V.; Wu, Qi; Li, Min; Fang, Ye

    2013-05-01

    We report the use of total internal reflection fluorescence (TIRF) microscopy for analyzing receptor pharmacology and the development of a microplate-compatible TIRF imaging system. Using stably expressed green fluorescence protein tagged β2-adrenergic receptor as the reporter, we found that the activation of different receptors results in distinct kinetic signatures of the TIRF intensity of cells. These TIRF signatures closely resemble the characteristics of their respective label-free dynamic mass redistribution signals in the same cells. This suggests that TIRF in microplate can be used for profiling and screening drugs.

  5. A total internal reflection-fluorescence correlation spectroscopy setup with pulsed diode laser excitation.

    Science.gov (United States)

    Weger, Lukas; Hoffmann-Jacobsen, Kerstin

    2017-09-01

    Fluorescence correlation spectroscopy (FCS) measures fluctuations in a (sub-)femtoliter volume to analyze the diffusive behavior of fluorescent particles. This highly sensitive method has proven to be useful for the analysis of dynamic biological systems as well as in chemistry, physics, and material sciences. It is routinely performed with commercial fluorescence microscopes, which provide a confined observation volume by the confocal technique. The evanescent wave of total internal reflectance (TIR) is used in home-built systems to permit a surface sensitive FCS analysis. We present a combined confocal and TIR-FCS setup which uses economic low-power pulsed diode lasers for excitation. Excitation and detection are coupled to time-correlated photon counting hardware. This allows simultaneous fluorescence lifetime and FCS measurements in a surface-sensitive mode. Moreover, the setup supports fluorescence lifetime correlation spectroscopy at surfaces. The excitation can be easily switched between TIR and epi-illumination to compare the surface properties with those in liquid bulk. The capabilities of the presented setup are demonstrated by measuring the diffusion coefficients of a free dye molecule, a labeled polyethylene glycol, and a fluorescent nanoparticle in confocal as well as in TIR-FCS.

  6. Thin-film-based sensitivity enhancement for total internal reflection fluorescence live-cell imaging.

    Science.gov (United States)

    Kim, Kyujung; Cho, Eun-Jin; Huh, Yong-Min; Kim, Donghyun

    2007-11-01

    We investigated experimentally the evanescent field enhancement based on dielectric thin films in total internal reflection microscopy. The sample employed two layers of Al2O3 and SiO2 deposited on an SF10 glass substrate. Field intensity enhancement measured by fluorescent excitation of microbeads relative to that of a control sample without dielectric films was polarization dependent, determined as 4.2 and 2.4 for TE and TM polarizations, respectively, and was in good agreement with numerical results. The thin-film-based field enhancement was also applied to live-cell imaging of quantum dots, which confirmed the sensitivity enhancement qualitatively.

  7. Single cell adhesion strength assessed with variable-angle total internal reflection fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Marcelina Cardoso Dos Santos

    2017-06-01

    Full Text Available We propose a new strategy to evaluate adhesion strength at the single cell level. This approach involves variable-angle total internal reflection fluorescence microscopy to monitor in real time the topography of cell membranes, i.e. a map of the membrane/substrate separation distance. According to the Boltzmann distribution, both potential energy profile and dissociation energy related to the interactions between the cell membrane and the substrate were determined from the membrane topography. We have highlighted on glass substrates coated with poly-L-lysine and fibronectin, that the dissociation energy is a reliable parameter to quantify the adhesion strength of MDA-MB-231 motile cells.

  8. Nanograting-based plasmon enhancement for total internal reflection fluorescence microscopy of live cells

    International Nuclear Information System (INIS)

    Kim, Kyujung; Cho, Eun-Jin; Suh, Jin-Suck; Huh, Yong-Min; Kim, Donghyun; Kim, Dong Jun

    2009-01-01

    We investigated evanescent field enhancement based on subwavelength nanogratings for improved sensitivity in total internal reflection microscopy of live cells. The field enhancement is associated with subwavelength-grating-coupled plasmon excitation. An optimum sample employed a silver grating on a silver film and an SF10 glass substrate. Field intensity was enhanced by approximately 90% when measured by fluorescent excitation of microbeads relative to that on a bare prism as a control, which is in good agreement with numerical results. The subwavelength-grating-mediated field enhancement was also applied to live cell imaging of quantum dots, which confirmed the sensitivity enhancement qualitatively.

  9. Quantifying the Assembly of Multicomponent Molecular Machines by Single-Molecule Total Internal Reflection Fluorescence Microscopy.

    Science.gov (United States)

    Boehm, E M; Subramanyam, S; Ghoneim, M; Washington, M Todd; Spies, M

    2016-01-01

    Large, dynamic macromolecular complexes play essential roles in many cellular processes. Knowing how the components of these complexes associate with one another and undergo structural rearrangements is critical to understanding how they function. Single-molecule total internal reflection fluorescence (TIRF) microscopy is a powerful approach for addressing these fundamental issues. In this article, we first discuss single-molecule TIRF microscopes and strategies to immobilize and fluorescently label macromolecules. We then review the use of single-molecule TIRF microscopy to study the formation of binary macromolecular complexes using one-color imaging and inhibitors. We conclude with a discussion of the use of TIRF microscopy to examine the formation of higher-order (i.e., ternary) complexes using multicolor setups. The focus throughout this article is on experimental design, controls, data acquisition, and data analysis. We hope that single-molecule TIRF microscopy, which has largely been the province of specialists, will soon become as common in the tool box of biophysicists and biochemists as structural approaches have become today. © 2016 Elsevier Inc. All rights reserved.

  10. New light on ion channel imaging by total internal reflection fluorescence (TIRF) microscopy.

    Science.gov (United States)

    Yamamura, Hisao; Suzuki, Yoshiaki; Imaizumi, Yuji

    2015-05-01

    Ion channels play pivotal roles in a wide variety of cellular functions; therefore, their physiological characteristics, pharmacological responses, and molecular structures have been extensively investigated. However, the mobility of an ion channel itself in the cell membrane has not been examined in as much detail. A total internal reflection fluorescence (TIRF) microscope allows fluorophores to be imaged in a restricted region within an evanescent field of less than 200 nm from the interface of the coverslip and plasma membrane in living cells. Thus the TIRF microscope is useful for selectively visualizing the plasmalemmal surface and subplasmalemmal zone. In this review, we focused on a single-molecule analysis of the dynamic movement of ion channels in the plasma membrane using TIRF microscopy. We also described two single-molecule imaging techniques under TIRF microscopy: fluorescence resonance energy transfer (FRET) for the identification of molecules that interact with ion channels, and subunit counting for the determination of subunit stoichiometry in a functional channel. TIRF imaging can also be used to analyze spatiotemporal Ca(2+) events in the subplasmalemma. Single-molecule analyses of ion channels and localized Ca(2+) signals based on TIRF imaging provide beneficial pharmacological and physiological information concerning the functions of ion channels. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  11. Heterogeneous amylin fibril growth mechanisms imaged by total internal reflection fluorescence microscopy.

    Science.gov (United States)

    Patil, Sharadrao M; Mehta, Andrew; Jha, Suman; Alexandrescu, Andrei T

    2011-04-12

    Total internal reflection fluorescence microscopy has been used to visualize the fibrillization of amylin, a hormone which in aggregated forms plays a role in type 2 diabetes pathology. Data were obtained at acidic pH where fibrillization is hindered by the charging of histidine 18 and at slightly basic pH where the loss of charge on the histidine promotes aggregation. The experiments show three types of aggregate growth processes. In the earliest steps globular seeds are formed with some expanding radially during the course of the reaction. The dimensions of the globular seeds as well as their staining with the amyloid-specific dye thioflavin T indicate that they are plaques of short fibrils. The next species observed are fibrils that invariably grow from large globular seeds or smaller punctate granules. Fibril elongation appears to be unidirectional, although in some cases multiple fibrils radiate from a single seed or granule. After fibrils are formed, some show an increase in fluorescence intensity that we attribute to the growth of new fibrils alongside those previously formed. All three aggregation processes are suggestive of secondary (heterogeneous) nucleation mechanisms in which nucleation occurs on preformed fibrils. Consistently, electron micrographs show changes in fibril morphology well after fibrils are first formed, and the growth processes observed by fluorescence microscopy occur after the corresponding solution reactions have reached an initial apparent plateau. Taken together, the results highlight the importance of secondary nucleation in the fibrillization of amylin, as this could provide a pathway to continue fibril growth once an initial population of fibrils is established.

  12. High Refractive Index Silicone Gels for Simultaneous Total Internal Reflection Fluorescence and Traction Force Microscopy of Adherent Cells

    Science.gov (United States)

    Besser, Achim; Sundd, Prithu; Ley, Klaus; Danuser, Gaudenz; Ginsberg, Mark H.; Groisman, Alex

    2011-01-01

    Substrate rigidity profoundly impacts cellular behaviors such as migration, gene expression, and cell fate. Total Internal Reflection Fluorescence (TIRF) microscopy enables selective visualization of the dynamics of substrate adhesions, vesicle trafficking, and biochemical signaling at the cell-substrate interface. Here we apply high-refractive-index silicone gels to perform TIRF microscopy on substrates with a wide range of physiological elastic moduli and simultaneously measure traction forces exerted by cells on the substrate. PMID:21961031

  13. Direct visualization of the reaction transformation and signal amplification in a DNA molecular machine with total internal reflection fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Rui eRen

    2013-10-01

    Full Text Available In this study, as a proof of concept, the signal amplification in an artificial DNA molecular machine was directly visualized via total internal reflection fluorescence microscopy (TIRFM. The molecular machine brought about obvious morphology change in DNA nanostructures as well as signal amplifications. On one hand, through a triggered and autonomically repeated RCA, a DNA nano-complex featuring a locked circular DNA template (serving as raw feed was converted into a long periodically repeated strand, i.e. the RCA products. Furthermore, this RCA was repeated in three controllable reaction phases, bring about progressive signal amplification. It was testified that the RCA products (presented as long thread-like fluorescent objects can be easily distinguished from the inputted DNA probes (presented as fluorescent dots, thus the transformation in reaction can be visualized. Also, by quantitive counting of the aforementioned fluorescence objects, the progress of the reaction through the phases, along with time, and over the lysozyme concentration can be demonstrated through TIRFM visualization. Overall, it was demonstrated that TIRFM is an efficient approach to quantitively visualize the biochemical processes at single-molecule level.

  14. 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.

  15. Imaging exocytosis of single glucagon-like peptide-1 containing granules in a murine enteroendocrine cell line with total internal reflection fluorescent microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohara-Imaizumi, Mica; Aoyagi, Kyota [Department of Biochemistry, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 (Japan); Akimoto, Yoshihiro [Department of Anatomy, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 (Japan); Nakamichi, Yoko; Nishiwaki, Chiyono [Department of Biochemistry, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 (Japan); Kawakami, Hayato [Department of Anatomy, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 (Japan); Nagamatsu, Shinya, E-mail: shinya@ks.kyorin-u.ac.jp [Department of Biochemistry, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 (Japan)

    2009-12-04

    To analyze the exocytosis of glucagon-like peptide-1 (GLP-1) granules, we imaged the motion of GLP-1 granules labeled with enhanced yellow fluorescent protein (Venus) fused to human growth hormone (hGH-Venus) in an enteroendocrine cell line, STC-1 cells, by total internal reflection fluorescent (TIRF) microscopy. We found glucose stimulation caused biphasic GLP-1 granule exocytosis: during the first phase, fusion events occurred from two types of granules (previously docked granules and newcomers), and thereafter continuous fusion was observed mostly from newcomers during the second phase. Closely similar to the insulin granule fusion from pancreatic {beta} cells, the regulated biphasic exocytosis from two types of granules may be a common mechanism in glucose-evoked hormone release from endocrine cells.

  16. Total reflection x-ray fluorescence (TXRF)

    International Nuclear Information System (INIS)

    Hockett, R.S.

    1995-01-01

    Total reflection X-Ray Fluorescence (TXRF) is a glancing x-ray analytical technique which is used primarily to measure surface metal contamination on semiconductor substrates. This is a review of Total reflection X-Ray Fluorescence (TXRF) applications for silicon semiconductor processing. In addition, some comments are made about the future of TXRF, and in particular, synchrotron radiation TXRF (SR-TXRF)

  17. Total internal reflection fluorescence (TIRF) microscopy for real-time imaging of nanoparticle-cell plasma membrane interaction

    DEFF Research Database (Denmark)

    Parhamifar, Ladan; Moghimi, Seyed Moien

    2012-01-01

    fluorescence (TIRF) microscopy allows for real-time monitoring of nanoparticle-membrane interaction events, which can provide vital information in relation to design and surface engineering of therapeutic nanoparticles for cell-specific targeting. In contrast to other microscopy techniques, the bleaching...... effect by lasers in TIRF microscopy is considerably less when using fluorescent nanoparticles and it reduces photo-induced cytotoxicity during visualization of live-cell events since it only illuminates the specific area near or at the plasma membrane....

  18. Three-dimensional particle tracking in concave structures made by ultraviolet nanoimprint via total internal reflection fluorescence microscopy and refractive-index-matching method

    Science.gov (United States)

    Fujinami, Taku; Kigami, Hiroshi; Unno, Noriyuki; Taniguchi, Jun; Satake, Shin-ichi

    2018-03-01

    Total internal reflection fluorescence microscopy (TIRFM) is a promising method for measuring fluid flow close to a wall with nanoscale resolution in a process that is termed "multilayer nanoparticle image velocimetry" (MnPIV). TIRFM uses evanescent light that is generated on a substrate (typically a glass slide) by total internal reflection of light. Many researchers have previously studied x-y-z (3D) flows of water close to flat glass slides using MnPIV. On the other hand, a fluid flow close to a structured surface is also important. To measure flows of water near micro-patterns, we previously developed an MnPIV technique that uses a refractive-index-matching method. In previous study, the micropattern is made of a thermoplastic material with a refractive index that closely matches that of water. In this study, ultraviolet nanoimprint lithography was used for fabricating the appropriate micro-patterns because this technique can fabricate a pattern with a high resolution. As a result, we succeeded in performing MnPIV in water with a circular hole array pattern made by ultraviolet nanoimprint using a refractive-index-matching method. We believe that this technique will be helpful in elucidating fluid flows around microstructures.

  19. Total internal reflection fluorescence anisotropy imaging microscopy: setup, calibration, and data processing for protein polymerization measurements in living cells

    Science.gov (United States)

    Ströhl, Florian; Wong, Hovy H. W.; Holt, Christine E.; Kaminski, Clemens F.

    2018-01-01

    Fluorescence anisotropy imaging microscopy (FAIM) measures the depolarization properties of fluorophores to deduce molecular changes in their environment. For successful FAIM, several design principles have to be considered and a thorough system-specific calibration protocol is paramount. One important calibration parameter is the G factor, which describes the system-induced errors for different polarization states of light. The determination and calibration of the G factor is discussed in detail in this article. We present a novel measurement strategy, which is particularly suitable for FAIM with high numerical aperture objectives operating in TIRF illumination mode. The method makes use of evanescent fields that excite the sample with a polarization direction perpendicular to the image plane. Furthermore, we have developed an ImageJ/Fiji plugin, AniCalc, for FAIM data processing. We demonstrate the capabilities of our TIRF-FAIM system by measuring β -actin polymerization in human embryonic kidney cells and in retinal neurons.

  20. Forensic application of total reflection X-ray fluorescence spectrometry for elemental characterization of ink samples

    International Nuclear Information System (INIS)

    Dhara, Sangita; Misra, N.L.; Maind, S.D.; Kumar, Sanjukta A.; Chattopadhyay, N.; Aggarwal, S.K.

    2010-01-01

    The possibility of applying Total Reflection X-ray Fluorescence for qualitative and quantitative differentiation of documents printed with rare earth tagged and untagged inks has been explored in this paper. For qualitative differentiation, a very small amount of ink was loosened from the printed documents by smoothly rubbing with a new clean blade without destroying the manuscript. 50 μL of Milli-Q water was put on this loose powder, on the manuscript, and was agitated by sucking and releasing the suspension two to three times with the help of a micropipette. The resultant dispersion was deposited on quartz sample support for Total Reflection X-ray Fluorescence measurements. The Total Reflection X-ray Fluorescence spectrum of tagged and untagged inks could be clearly differentiated. In order to see the applicability of Total Reflection X-ray Fluorescence for quantitative determinations of rare earths and also to countercheck such determinations in ink samples, the amounts of rare earth in painted papers with single rare earth tagged inks were determined by digesting the painted paper in HNO 3 /HClO 4 , mixing this solution with the internal standard and recording their Total Reflection X-ray Fluorescence spectra after calibration of the instrument. The results thus obtained were compared with those obtained by Inductively Coupled Plasma Mass Spectrometry and were found in good agreement. The average precision of the Total Reflection X-ray Fluorescence determinations was 5.5% (1σ) and the average deviation of Total Reflection X-ray Fluorescence determined values with that of Inductively Coupled Plasma Mass Spectrometry was 7.3%. These studies have shown that Total Reflection X-ray Fluorescence offers a promising and potential application in forensic work of this nature.

  1. Reflections on international medical law.

    Science.gov (United States)

    Wattad, Mohammed S; Hrevtsova, Radmyla Yu

    2011-12-01

    Does international medical law exist, in the first place, as an independent area of study? If so, is it urgently required in an era of comparative studies? Namely, to what extent, if at all, international studies differ from comparative ones? Besides, what are the particular characteristics of such international discipline? Namely, what are the particular features of this field that elaborate on our legal and scientific understanding in sketching possible definition for this notion of "international medical law?" In addition, how does international medical law correlate with health, ethics and health policies in our globalized world? And finally, what are the challenges that might face the international community, once the concept of "international medical law" is acknowledged? This papers aims at establishing the conceptual grounds for these questions, thus calling for the acknowledgment of a new field of study described as "international medical law".

  2. Studies of the Reflection, Refraction and Internal Reflection of Light

    Science.gov (United States)

    Lanchester, P. C.

    2014-01-01

    An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…

  3. Application of total reflection x-ray fluorescence (TXRF) technique ...

    African Journals Online (AJOL)

    Nigerian crude oils from eight oil wells have been analysed for the following trace elements: Ni, Cr, Mn, V, Fe, Zn. Pb, Cu, Co and S using total Reflection X-ray Fluorescence (TXRF) analytical method. Concentrations of these elements were found to range from 0.002 – 1.420 ppm. Results showed that Fe was the most ...

  4. Determination of technetium by total reflection x-ray fluorescence

    International Nuclear Information System (INIS)

    Bermudez, J.I.; Greaves, E.D.; Nemeth, P.

    2000-01-01

    We describe a technique using total reflection x-ray fluorescence (TXRF) for determination of Technetium produced by elution of chromatography generators with physiological saline solutions. The analysis with the 18.41 keV K α line of Technetium was accomplished with monochromatized K α radiation from a silver anode x-ray tube operated at 45 keV and 20 mA. This radiation at 22.104 keV is efficiently coupled to the 21.054 keV absorption edge of Tc. It is also of advantage in the direct analysis of organic and saline properties of the Tc-bearing samples. Quantification was accomplished by internal standard addition of Ga and using an interpolated value of the sensitivity for Tc between Molybdenum and Rhenium. Data processing was carried out with the QXAS-AXIL software package. System sensitivity was found adequate for direct Tc determination of eluted saline solutions. The interest and advantages of the use of the technique as an auxiliary in the synthesis and characterization of Tc-labeled radiopharmaceuticals used for diagnosis in nuclear medicine are discussed. Detection limits in the matrices analyzed are reported. (author)

  5. Measurement uncertainty in Total Reflection X-ray Fluorescence

    Science.gov (United States)

    Floor, G. H.; Queralt, I.; Hidalgo, M.; Marguí, E.

    2015-09-01

    Total Reflection X-ray Fluorescence (TXRF) spectrometry is a multi-elemental technique using micro-volumes of sample. This work assessed the components contributing to the combined uncertainty budget associated with TXRF measurements using Cu and Fe concentrations in different spiked and natural water samples as an example. The results showed that an uncertainty estimation based solely on the count statistics of the analyte is not a realistic estimation of the overall uncertainty, since the depositional repeatability and the relative sensitivity between the analyte and the internal standard are important contributions to the uncertainty budget. The uncertainty on the instrumental repeatability and sensitivity factor could be estimated and as such, potentially relatively straightforward implemented in the TXRF instrument software. However, the depositional repeatability varied significantly from sample to sample and between elemental ratios and the controlling factors are not well understood. By a lack of theoretical prediction of the depositional repeatability, the uncertainty budget can be based on repeat measurements using different reflectors. A simple approach to estimate the uncertainty was presented. The measurement procedure implemented and the uncertainty estimation processes developed were validated from the agreement with results obtained by inductively coupled plasma - optical emission spectrometry (ICP-OES) and/or reference/calculated values.

  6. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    International Nuclear Information System (INIS)

    Campbell, P.K. Entcheva; Middleton, E.M.; Corp, L.A.; Kim, M.S.

    2008-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance data, which provide estimates of vigor based primarily on chlorophyll content. Chlorophyll fluorescence (ChlF) measurements offer a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, technology based on ChlF may allow more accurate carbon sequestration estimates and earlier stress detection than is possible when using reflectance data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contributions from both the reflected and fluoresced radiation. The aim of this study is to determine the relative contributions of reflectance and ChlF fractions to Ra in the red to near-infrared region (650-800 nm) of the spectrum. The practical objectives of the study are to: 1) evaluate the relationship between ChlF and reflectance at the foliar level for corn, soybean and maple; and 2) for corn, determine if the relationship established for healthy vegetation changes under nitrogen (N) deficiency. To obtain generally applicable results, experimental measurements were conducted on unrelated crop and tree species (corn, soybean and maple) under controlled conditions and a gradient of inorganic N fertilization levels. Optical reflectance spectra and actively induced ChlF emissions were collected on the same foliar samples, in conjunction with measurements of photosynthetic function, pigment levels, and carbon (C) and N content. The spectral trends were examined for similarities. On average, 10-20% of Ra at 685 nm was actually due to ChlF. The spectral trends in steady state and maximum fluorescence varied significantly, with steady state fluorescence (especially red, 685 nm) showing higher ability for species and treatment separation. The relative contribution of ChlF to Ra varied significantly among species, with maple

  7. Total internal reflection effect on gyrotropic interface

    Science.gov (United States)

    Glushchenko, Alexander G.; Glushchenko, Eugene P.; Zhukov, Sergey V.

    2018-02-01

    This article considers the physical features of total internal reflection at gyrotropic and isotropic interfaces for two cases: electrical gyrotropy (plasma) and magnetic gyrotropy (ferrite). It is shown that the plasma magnetization may lead to the formation of the total internal reflection effect, which does not occur in isotropic plasma. The threshold values of the magnetic field, which are necessary for the total internal reflection effect, are determined. The total internal reflection effect on a ferrite-dielectric interface for waves emanating from different angles is observed in various frequency ranges and magnetization fields. The study points out the possibility of changing the total internal reflection angle value in large limits due to a change in the external magnetic field magnitude. The calculation results of the total internal reflection angle dependence on the external magnetic field magnitude are presented. The formulas are elaborated for calculating the total internal reflection angles of different interfaces for gyrotropic and isotropic media. The generalized formulas are defined for calculating the Doppler effect in the gyrotropic media. The study demonstrates how the velocity of the media interface affects the limiting angle of total internal refection.

  8. Measurement uncertainty in Total Reflection X-ray Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Floor, G.H., E-mail: geerke.floor@gfz-potsdam.de [GFZ German Research Centre for Geosciences Section 3.4. Earth Surface Geochemistry, Telegrafenberg, 14473 Postdam (Germany); Queralt, I. [Institute of Earth Sciences Jaume Almera ICTJA-CSIC, Solé Sabaris s/n, 08028 Barcelona (Spain); Hidalgo, M.; Marguí, E. [Department of Chemistry, University of Girona, Campus Montilivi s/n, 17071 Girona (Spain)

    2015-09-01

    Total Reflection X-ray Fluorescence (TXRF) spectrometry is a multi-elemental technique using micro-volumes of sample. This work assessed the components contributing to the combined uncertainty budget associated with TXRF measurements using Cu and Fe concentrations in different spiked and natural water samples as an example. The results showed that an uncertainty estimation based solely on the count statistics of the analyte is not a realistic estimation of the overall uncertainty, since the depositional repeatability and the relative sensitivity between the analyte and the internal standard are important contributions to the uncertainty budget. The uncertainty on the instrumental repeatability and sensitivity factor could be estimated and as such, potentially relatively straightforward implemented in the TXRF instrument software. However, the depositional repeatability varied significantly from sample to sample and between elemental ratios and the controlling factors are not well understood. By a lack of theoretical prediction of the depositional repeatability, the uncertainty budget can be based on repeat measurements using different reflectors. A simple approach to estimate the uncertainty was presented. The measurement procedure implemented and the uncertainty estimation processes developed were validated from the agreement with results obtained by inductively coupled plasma — optical emission spectrometry (ICP-OES) and/or reference/calculated values. - Highlights: • The uncertainty of TXRF cannot be realistically described by the counting statistics. • The depositional repeatability is an important contribution to the uncertainty. • Total combined uncertainties for Fe and Cu in waste/mine water samples were 4–8%. • Obtained concentrations agree within uncertainty with reference values.

  9. Total-reflection X-ray fluorescence analysis of Austrian wine

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, X. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Kregsamer, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Wobrauschek, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Streli, C. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria)]. E-mail: streli@ati.ac.at

    2006-11-15

    The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 {mu}l of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines.

  10. Total-reflection X-ray fluorescence analysis of Austrian wine

    International Nuclear Information System (INIS)

    Gruber, X.; Kregsamer, P.; Wobrauschek, P.; Streli, C.

    2006-01-01

    The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 μl of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines

  11. Total reflection x-ray fluorescence - an approach to nanoanalysis

    International Nuclear Information System (INIS)

    Klockenkaemper, R.

    2000-01-01

    X-ray fluorescence analysis (XRFA) is a powerful tool used for industrial production, geological prospecting and for environmental control. However, the method suffers from a lack of sensitivity so that analyses are restricted to microanalytical investigations. That means: the sample amount needed for analysis is above some 10 micrograms, concentrations to be determined have to be on the μg/ml level, and thin layers to be characterized must be of micrometer thickness. In contrast to conventional XRFA, total-reflection X-ray fluorescence (TXRF) is extremely sensitive and even allows nano-analytical investigations. Three different ways can be taken: (i) use of minute sample amounts of only 10 nano-grams, (ii) determination of extreme traces below ng/ml and (iii) surface analysis and depth profiling of shallow layers with nano-meter thickness. In this lecture, the basic physical phenomena of total reflection and standing waves are outlined. The experimental equipment for TXRF is sketched out and commercially available instruments of different manufacturers are compared. Furthermore, examples are given for the three kinds of nano-analytical applications: ultra-micro, analysis, ultra trace analysis and mono- and thin-layer analysis. (author)

  12. Beer analysis by synchrotron radiation total reflection X-ray fluorescence (SR-TXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br; Zucchi, Orgheda L.D.A. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas de Ribeirao Preto]. E-mail: olzucchi@fcfrp.usp.br

    2005-07-01

    In this work the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn and Br in twenty-nine brands of national and international beers were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF). The results were compared with the limits established by the Brazilian Legislation and the nutritive values established by National Agricultural Library (NAL). The measurements were performed at the X-ray Fluorescence Beamline at Synchrotron Light Source Laboratory, in Campinas, Sao Paulo, Brazil, using a polychromatic beam for excitation. A small volume of 5 {mu}L of sample beers containing just an internal standard, used to correct geometry effects, were analyzed without any pre-treatment. The measuring time was 100 s and the detection limits obtained varied from 1{mu}g.L{sup -1} for Mn and Fe to 15{mu}g.L{sup -1} for P. (author)

  13. Beer analysis by synchrotron radiation total reflection X-ray fluorescence (SR-TXRF)

    International Nuclear Information System (INIS)

    Moreira, Silvana; Vives, Ana Elisa S. de; Nascimento Filho, Virgilio F.; Zucchi, Orgheda L.D.A.

    2005-01-01

    In this work the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn and Br in twenty-nine brands of national and international beers were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF). The results were compared with the limits established by the Brazilian Legislation and the nutritive values established by National Agricultural Library (NAL). The measurements were performed at the X-ray Fluorescence Beamline at Synchrotron Light Source Laboratory, in Campinas, Sao Paulo, Brazil, using a polychromatic beam for excitation. A small volume of 5 μL of sample beers containing just an internal standard, used to correct geometry effects, were analyzed without any pre-treatment. The measuring time was 100 s and the detection limits obtained varied from 1μg.L -1 for Mn and Fe to 15μg.L -1 for P. (author)

  14. Analysis of beers from Brazil with synchrotron radiation total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Moreira, S.; Vives, A.E.S.; Brienza, S.M.B.; Zucchi, O.L.A.D.; Jesus, E.F.O. de; Nascimento Filho, V.F.

    2006-01-01

    In this study the concentrations of P, S, Cl, K, Ca, Mn, Fe, Zn and Br in twenty-nine brands of national and international beers were determined by synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF). The results were compared with the limits established by the Brazilian legislation and the nutritional values established by National Agricultural Library (NAL, USA). The measurements were performed at the X-Ray Fluorescence Beamline at Brazilian National Synchrotron Light Laboratory, in Campinas, Sao Paulo, Brazil, using a polychromatic beam for excitation. A small volume of 5 μl of beers containing an internal standard used to correct geometry effects was analyzed without pretreatment. The measuring time was 100 seconds and the detection limits obtained varied from 1 μg x l -1 for Mn and Fe to 15 μg x l -1 for P. (author)

  15. Contribution of Chlorophyll Fluorescence to the Apparent Reflectance of Vegetation

    Science.gov (United States)

    Campbell, P. K. Entcheva; Middleton, E. M.; Kim, M. S.

    2007-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance (R) measurements, whi ch provide estimates of relative vegetation vigor based primarily on chlorophyll content. Vegetation chlorophyll fluorescence (CF) offers a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, monitoring of vegetation vigor based on CF may allow earlier stress detection and more accurate carbon sequestra tion estimates, than is possible using R data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contrib utions from both the reflected and fluoresced radiation. The aim of t his study is to determine the relative R and CF fractions contributing to Ra from the vegetation in the red to near-infrared region of the spectrum. The practical objectives of the study are to: 1) evaluate t he relationship between CF and R at the foliar level for corn, soybean, maple; and 2) for corn, determine if the relationship established f or healthy (optimal N) vegetation changes under N defiiency. To obtai n generally applicable results, experimental measurements were conducted on unrelated crop and tree species (maple, soybean and corn), unde r controlled conditions and a gradient of inorganic N fertilization l evels. Optical R spectra and actively induced CF emissions were obtained on the same foliar samples, in conjunction with measurements of p hotosynthetic function, pigment levels, and C and N content. The comm on spectral trends or similarities were examined. On average, 10-20% of apparent R at 685 nm was actually due to CF. The spectral trends in steady and maximum F varied significantly, with Fs (especially red) showing higher ability for species and treatment separation. The relative contribution of ChF to R varied significantly among species, with maple emitting much higher F amounts, as

  16. The capabilities of total reflection X-ray fluorescence in the polymeric analytical field

    International Nuclear Information System (INIS)

    Vazquez, Cristina

    2004-01-01

    This paper presents the capabilities of total reflection X-ray fluorescence (TXRF) as analytical technique specially focused in high-viscosity polymer dispersions. Appropriate sample preparation procedures are described taking into account the time stability of these dispersions. Special remarks considering different ways for drying samples in order to obtain the most uniform deposited film are investigated focusing on the behavior of aqueous and viscous systems. Due to the difficulty found for obtaining a homogeneous mixture between sample and internal standard in such systems, the use of Compton incoherent scattering is discussed as an alternative procedure for trace quantification in high viscous systems without any mixing processes

  17. The capabilities of total reflection X-ray fluorescence in the polymeric analytical field*1

    Science.gov (United States)

    Vázquez, Cristina

    2004-08-01

    This paper presents the capabilities of total reflection X-ray fluorescence (TXRF) as analytical technique specially focused in high-viscosity polymer dispersions. Appropriate sample preparation procedures are described taking into account the time stability of these dispersions. Special remarks considering different ways for drying samples in order to obtain the most uniform deposited film are investigated focusing on the behavior of aqueous and viscous systems. Due to the difficulty found for obtaining a homogeneous mixture between sample and internal standard in such systems, the use of Compton incoherent scattering is discussed as an alternative procedure for trace quantification in high viscous systems without any mixing processes.

  18. Total internal reflection tomography of small objects

    International Nuclear Information System (INIS)

    Chen Xudong

    2008-01-01

    The multiple signal classification (MUSIC) imaging method is applied to determine the locations of a collection of small anisotropic spherical scatterers in the framework of the total internal reflection tomography. Multiple scattering between scatterers is considered and the inverse scattering problem is nonlinear, which, however, is solved by the proposed fast analytical approach where no associated forward problem is iteratively evaluated. The paper also discusses the role of the polarization of incidence waves, the incidence angle, the separation of scatterers from the surface of the substrate, and the level of noise on the resolution of imaging.

  19. Polarization contrast in fluorescence scanning near-field optical microscopy in reflection

    NARCIS (Netherlands)

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Polarization contrast is presented in fluorescence images of a Langmuir-Blodgett monolayer obtained with a scanning near-field optical microscope operated in reflection. A tapered optical fiber is used both to excite and to collect the fluorescence. The lateral resolution in the reflection

  20. Total Internal Reflections - Dr. Kapolka Explains Frustrated Total Internal Reflection [video

    OpenAIRE

    Naval Postgraduate School Physics

    2015-01-01

    NPS Physics In-class Physics Demonstrations This is a demo about frustrated total internal reflection. This is a general phenomenon that applies to any kind of wave phenomenon including quantum mechanical waves. Dr. Kapolka is physics professor at the Naval Postgraduate school.

  1. Chlorine determination in (U, Pu)C fuel by total reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Misra, Nand Lal; Dhara, Sangita; Mudher, Khush Dev Singh; Aggarwal, Suresh K.; Thakur, Uday Kumar; Shah, Dipti; Sawant, R.M.; Ramakumar, K.L.

    2007-01-01

    A Total Reflection X-ray Fluorescence (TXRF) method for the determination of chlorine in (U,Pu)C has been developed. The method involves calibration of the instrument with standard solutions and validation of TXRF determination of chlorine using synthetic standard solutions. Cl K α line excited with W L α source was used for TXRF determinations of chlorine. Chlorine present in trace amounts in (U,Pu)C samples was first separated by pyro hydrolysis. The evolved chlorine, in form of HCl, was collected in 5 mM NaOH solution. This solution was analyzed for chlorine by Total Reflection X-ray Fluorescence Spectrometry using cobalt as an internal standard. The TXRF detection limit of chlorine was found to be 3.6 pg with sample size of 30 μL. In order to assess the applicability of TXRF method for chlorine determinations in other nuclear materials, one U 3 O 8 trace element standard was also analyzed for chlorine in similar way. The precision of the method was found to be 25% (1 σ) at ng level in most of the cases. (author)

  2. Fluorescence enhancement and reflection of the excitation light observed with a multilayered substrate.

    Science.gov (United States)

    Akimoto, Takuo; Yasuda, Mitsuru

    2010-01-01

    Fluorescence enhancement from a multilayered substrate fabricated with Ag and Al(2)O(3) was investigated using fluorescein, rhodamine B, Cy3, and Cy5 as fluorophores. The change in the fluorescence enhancement with Al(2)O(3) had two peaks and one valley in the range from 0 to 300 nm of Al(2)O(3) thickness, and such peaks and valley were found to appear periodically. Moreover, the reflection of the excitation light from the multilayered substrate was investigated. The reflection of the excitation light periodically changed depending on the Al(2)O(3) thickness as well, and the maximum reflection was observed near the Al(2)O(3) thickness of the peak fluorescence enhancement. It was found that the periodic changes of the fluorescence enhancement and the reflection of the excitation light could be explained, for the most part, with the integral multiples of the lambda/4 derived by a simple interference theory.

  3. Dielectric and fluorescent samples imaged by scanning near-field optical microscopy in reflection

    OpenAIRE

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Dielectric fluorescent samples are imaged by scanning near- field optical microscopy in reflection. A non-metallized tapered fibre tip is used both as an emitter and a detector. Shear force feedback controls the distance between the tip and the sample and gives simultaneously a topographic image of the surface. A direct correlation with the optical image is obtained. We demonstrate that this reflection setup is suitable for dielectric samples. Images in fluorescence have been obtained o­n Lan...

  4. Determination of halide ions in solution by Total Reflection X-ray Fluorescence (TXRF) spectrometry.

    Science.gov (United States)

    Vander Hoogerstraete, Tom; Jamar, Steven; Wellens, Sil; Binnemans, Koen

    2014-02-04

    An accurate quantitative determination of halide ions X (X = Cl, Br, I) in aqueous solution by total reflection X-ray fluorescence (TXRF) is not possible using the traditional acidic internal standards. In general, the standard solutions are highly acidic (e.g., Ga(NO3)3 in HNO3) to avoid precipitation of hydroxides of the standard element and to obtain a stable and reliable standard. In acidic solutions, dissolved halide salts can exchange their cation for a proton. The resulting volatile HX compounds can evaporate during the drying procedure of the TXRF sample preparation. In this technical note, we show that an alkaline Cu(NH3)4(NO3)2 standard can be used for the determination of chlorine, bromine and iodine without facing problems of HX evaporation.

  5. Quenched carbonaceous composite - Fluorescence spectrum compared to the extended red emission observed in reflection nebulae

    Science.gov (United States)

    Sakata, Akira; Wada, Setsuko; Narisawa, Takatoshi; Asano, Yoichi; Iijima, Yutaka; Onaka, Takashi; Tokunaga, Alan T.

    1992-01-01

    The photoluminescence (fluorescence) of a film of the laboratory-synthesized quenched carbonaceous composite (filmy QCC) is shown to have a single broad emission feature with a peak wavelength that varies from 670 to 725 nm, and coincides with that of the extended red emission observed in reflection nebulae. The rapid decay of the filmy QCC red fluorescence in air and of the stable blue fluorescence of the filmy QCC dissolved in liquid Freon suggests that the red fluorescence originates from the interaction of active chemical species and aromatic components in the filmy QCC. A material similar in nature to that of the filmy QCC may be a major component of interstellar dust.

  6. Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Gallardo, Helena; Queralt, Ignasi; Tapias, Josefina; Candela, Lucila; Margui, Eva

    2016-08-01

    Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L(-1). Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Forensic applications of microscopical infrared internal reflection spectroscopy

    Science.gov (United States)

    Tungol, Mary W.; Bartick, Edward G.; Reffner, John A.

    1994-01-01

    Applications of microscopical infrared internal reflection spectroscopy in forensic science are discussed. Internal reflection spectra of single fibers, hairs, paint chips, vehicle rubber bumpers, photocopy toners, carbon copies, writing ink on paper, lipstick on tissue, black electrical tape, and other types of forensic evidence have been obtained. The technique is convenient, non-destructive, and may permit smeared materials to be analyzed in situ.

  8. Limits of detection of a total reflection X-ray fluorescence system with double reflection module.

    Science.gov (United States)

    Nascimento Filho, V F; Poblete, V H; Parreira, P S; Matsumoto, E; Simabuco, S M; Espinoza, E P; Navarro, A A

    1999-01-01

    An X-ray tube with a Mo target and Zr filter, operated at 45 kV/20 mA, was used to excite samples (5 microL deposited on a quartz support) and the total reflection angle condition was obtained with a double reflector module built with two 10-cm-long 7-mm-thick quartz crystals placed 50 microns apart. A high-resolution spectrometer based on a Si(Li) detector coupled to a multichannel analyzer was used for X-ray detection and the spectra were interpreted with the AXIL software. The system was calibrated with standard chemical solutions containing Cr, Fe, Cu, Zn, and Pb, and Y was used as an internal standard to correct eventual geometric errors and high-voltage instabilities of the X-ray generator. The limits of detection were 19, 9, 5, and 4 ng/mL for Cr, Fe, Cu, and Zn, respectively, analyzed through characteristic K alpha X-rays, and 7 ng/mL for Pb, through L alpha X-rays, considering 50 microL samples deposited and dried on a quartz support, to be excited/detected for 1000 s.

  9. Spectral Behavior of White Pigment Mixtures Using Reflectance, Ultraviolet-Fluorescence Spectroscopy, and Multispectral Imaging.

    Science.gov (United States)

    Pronti, Lucilla; Felici, Anna Candida; Ménager, Matthieu; Vieillescazes, Cathy; Piacentini, Mario

    2017-12-01

    Reflectance spectroscopy, ultraviolet (UV)-fluorescence spectroscopy, and multispectral imaging have been widely employed for pigment identification on paintings. From ancient times to the present, lead white, zinc white, and titanium white have been the most important white pigments used for paintings and they are used as pigment markers for dating a work of art. The spectral behavior of these pigments is reported in several scientific papers and websites, but those of their mixtures are quite unknown. We present a combined nondestructive approach for identifying mixtures of lead white, zinc white, and titanium white as powder and dispersed in two different binder media (egg yolk and linseed oil) by using reflectance spectroscopy, spectrofluorimetry, multispectral reflectance and UV-fluorescence imaging. We propose a novel approach for mapping the presence of white pigments in paintings by false color images obtained from multispectral reflectance and UV-fluorescence images. We found that the presence of lead white mixed with either zinc white or titanium white is highly detectable. Zinc white mixed with lead white or titanium white can be identified due to its UV-fluorescence emission, whereas titanium white in association with lead white or zinc white is distinguishable by its reflectance spectral features. In most cases, the UV-fluorescence analyses also permit the recognition of the binder media in which the pigments are dispersed.

  10. Determination of copper, iron and zinc in spirituous beverages by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Capote, T.; Marcó, L. M.; Alvarado, J.; Greaves, E. D.

    1999-10-01

    The concentration of copper in traditional homemade alcoholic distillates produced in Venezuela (Cocuy de Penca) were determined by total reflection X-ray fluorescence (TXRF) using vanadium as internal standard. The results were compared to those obtained by flame atomic absorption spectrometry (FAAS). Three preparative methods of addition of vanadium were compared: classical internal standard addition, 'layer on layer' internal standard addition and in situ addition of internal standard. The TXRF procedures were accurate and the precision was comparable to that obtained by the FAAS technique. Copper levels were above the maximum allowed limits for similar beverages. Zinc and iron in commercial and homemade distilled beverages were also analyzed by TXRF with in situ addition of internal standard demonstrating the usefulness of this technique for trace metal determination in distillates.

  11. Analysis of archaeological ceramics by total-reflection X-ray fluorescence: Quantitative approaches

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Ruiz, R. [Servicio Interdepartamental de Investigacion, Facultad de Ciencias, Universidad Autonoma de Madrid, Modulo C-9, Laboratorio de TXRF, Crta. Colmenar, Km 15, Cantoblanco, E-28049, Madrid (Spain)], E-mail: ramon.fernandez@uam.es; Garcia-Heras, M. [Grupo de Arqueometria de Vidrios y Materiales Ceramicos, Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C/ Albasanz, 26-28, 28037 Madrid (Spain)

    2008-09-15

    This paper reports the quantitative methodologies developed for the compositional characterization of archaeological ceramics by total-reflection X-ray fluorescence at two levels. A first quantitative level which comprises an acid leaching procedure, and a second selective level, which seeks to increase the number of detectable elements by eliminating the iron present in the acid leaching procedure. Total-reflection X-ray fluorescence spectrometry has been compared, at a quantitative level, with Instrumental Neutron Activation Analysis in order to test its applicability to the study of this kind of materials. The combination of a solid chemical homogenization procedure previously reported with the quantitative methodologies here presented allows the total-reflection X-ray fluorescence to analyze 29 elements with acceptable analytical recoveries and accuracies.

  12. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Science.gov (United States)

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

  13. Reflections on Dead Theory in International Relations

    Science.gov (United States)

    Thakur, Vineet

    2016-01-01

    In this short autobiographical essay, I trace my journey in the discipline of International Relations. While entering the discipline, I, along with a host of my classmates, were enamoured by the exciting possibilities of thinking theoretically. Almost a decade later, those promises look bleak. From the perspective of a student in the discipline, I…

  14. Reflections about therapeutic internments and his specificity

    Directory of Open Access Journals (Sweden)

    Ángel Estalayo Hernández

    2014-10-01

    Full Text Available There are cases treated in detention centers that present some specificities with respect to other affordable educational strategies from social component. This we refer to the need to address situations in which the same symptom of transgression resulting in an offense that carries a legal measure has other bases that generate and / or maintain, or etiology marking its expression and so much attention. The approach to interventions with children and young people is a seriously disruptive content submitted to numerous debates, discussions and disagreements. In this regard, therapeutic placements would be for those cases in which the intervention on symptom requires a specific and specialized perspective. Beyond clinical approaches, therapeutic placements should from the intervention on self-regulation problems (emotional, behavioral, and cognitive and behavioral expression and as a key defining element. To this we add that we have observed in our practice in recent years an increase in problems related to the field of mental health and / or drug and alcohol consumption on children and young people entering the judicial context. This requires expertise and implement a therapeutic approach in centers for juvenile justice. It is particularly important in these cases performed from the beginning of internment clinical and social diagnostics to guide and design the specific educational and therapeutic intervention required for each particular case, in the interest of optimizing the operation and achieve higher levels of efficiency

  15. 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

  16. Total reflection X-ray fluorescence and energy-dispersive X-ray ...

    Indian Academy of Sciences (India)

    and radiation exposure to the detector and operator are minimum. Total reflection X-ray fluorescence (TXRF) is a comparatively new multielement analytical technique for trace element determinations [4,5]. It is a special variant of EDXRF where the X-ray beam falls at a flat polished sample support at an angle less than the ...

  17. Microanalysis of old violin varnishes by total-reflection X-ray fluorescence

    Science.gov (United States)

    von Bohlen, Alex; Meyer, Friedrich

    1997-07-01

    Total reflection X-ray fluorescence was used to characterize elements (with Z>13) contained in varnishes applied by prominent violin makers during the last five centuries. Direct analyses of small flakes with masses varnish. Higher amounts of Fe, As and Pb were found in old products, Mn, Co, Cu, Zn and Pb were used in more recent varnishes.

  18. Scientific and technical challenges in remote sensing of plant canopy reflectance and fluorescence

    Czech Academy of Sciences Publication Activity Database

    Malenovský, Z.; Mishra, Kumud; Zemek, František; Rascher, U.; Nedbal, Ladislav

    2009-01-01

    Roč. 10, č. 60 (2009), s. 2987-3004 ISSN 0022-0957 R&D Projects: GA MZe QH92034; GA MŠk OC09001 Institutional research plan: CEZ:AV0Z60870520 Keywords : Chlorophyll fluorescence * optical remote sensing * photosynthesis dynamics * reflectance Subject RIV: GK - Forestry Impact factor: 4.271, year: 2009

  19. Total reflection X-ray fluorescence and energy-dispersive X-ray ...

    Indian Academy of Sciences (India)

    India has an ambitious program for such electricity generation using different types of ... and radiation exposure to the detector and operator are minimum. Total reflection X-ray fluorescence (TXRF) is a comparatively new multielement analytical ... Difference in EDXRF spectrum of a mixed Y and U solution containing.

  20. Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

    NARCIS (Netherlands)

    Kromkamp, J.C.; Morris, E.P.; Forster, R.M.; Honeywill, C.; Hagerthey, S.; Paterson, D.M.

    2006-01-01

    Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two

  1. Dielectric and fluorescent samples imaged by scanning near-field optical microscopy in reflection

    NARCIS (Netherlands)

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Dielectric fluorescent samples are imaged by scanning near- field optical microscopy in reflection. A non-metallized tapered fibre tip is used both as an emitter and a detector. Shear force feedback controls the distance between the tip and the sample and gives simultaneously a topographic image of

  2. Total reflection X-ray fluorescence analysis of pollen as an indicator for atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Pepponi, G. E-mail: pepponi@itc.it; Lazzeri, P.; Coghe, N.; Bersani, M.; Gottardini, E.; Cristofolini, F.; Clauser, G.; Torboli, A

    2004-08-31

    The viability of pollen is affected by environmental pollution and its use as a bio-indicator is proposed. Such effects can be observed and quantified by biological tests. However, a more accurate identification of the agents affecting the viability is required in order to validate the biological assay for environmental monitoring. The chemical analysis of pollen is meant to ascertain the existence of a correlation between its reduced biological functions and the presence of pollutants. Moreover, such biological systems act as accumulators and allow the detection and quantification of species present in the environment at low concentrations. Total reflection X-ray fluorescence analysis (TXRF) has been chosen for the investigation due to its high sensitivity, multielement capability and wide dynamic range. Corylus avellana L. (hazel) pollen has been collected in areas with different anthropic impact in the province of Trento, Italy. For the TXRF measurements, a liquid sample is needed, especially if a quantitative analysis is required. In the present work, the analysis after a microwave digestion has been compared with the analysis of a suspension of the pollen samples. In both cases, an internal standard has been used for the quantification. The concentrations of 17 elements ranging from Al to Pb have been determined in 13 samples. Analysis of the suspensions showed to be comparable to that of digested samples in terms of spectral quality, but the latter preparation method gave better reproducibility. Sub-ppm lowest limits of detection were obtained for iron and heavier elements detected.

  3. Metal ions diffusion through polymeric matrices: A total reflection X-ray fluorescence study

    International Nuclear Information System (INIS)

    Boeykens, S.; Caracciolo, N.; D'Angelo, M.V.; Vazquez, C.

    2006-01-01

    This work proposes the use of X-ray fluorescence with total reflection geometry to explore the metal ions transport in aqueous hydrophilic polymer solutions. It is centered in the study of polymer concentration influence on ion diffusion. This subject is relevant to various and diverse applications, such as drug controlled release, microbiologic corrosion protection and enhanced oil recovery. It is anticipated that diffusion is influenced by various factors in these systems, including those specific to the diffusing species, such as charge, shape, molecular size, and those related to the structural complexity of the matrix as well as any specific interaction between the diffusing species and the matrix. The diffusion of nitrate salts of Ba and Mn (same charge, different hydrodynamic radii) through water-swollen polymeric solutions and gels in the 0.01% to 1% concentration ranges was investigated. The measurements of the metal concentration were performed by TXRF analysis using the scattered radiation by the sample as internal standard. Results are discussed according to different physical models for solute diffusion in polymeric solutions

  4. Total reflection X-ray fluorescence as a fast multielemental technique for human placenta sample analysis

    Science.gov (United States)

    Marguí, E.; Ricketts, P.; Fletcher, H.; Karydas, A. G.; Migliori, A.; Leani, J. J.; Hidalgo, M.; Queralt, I.; Voutchkov, M.

    2017-04-01

    In the present contribution, benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been evaluated as a cost-effective multielemental analytical technique for human placenta analysis. An easy and rapid sample preparation consisting of suspending 50 mg of sample in 1 mL of a Triton 1% solution in deionized water showed to be the most suitable for this kind of samples. However, for comparison purposes, an acidic microwave acidic digestion procedure was also applied. For both sample treatment methodologies, limits of detection for most elements were in the low mg/kg level. Accurate and precise results were obtained using internal standardization as quantification approach and applying a correction factor to compensate for absorption effects. The correction factor was based on the proportional ratio between the slurry preparation results and those obtained for the analysis of a set of human placenta samples analysed by microwave acidic digestion and ICP-AES analysis. As a study case, the developed TXRF methodology was applied for multielemental analysis (K, Ca, Fe, Cu, Zn, As, Se, Br, Rb and Sr) of several healthy women's placenta samples from two regions in Jamaica.

  5. Rainwater analysis by synchrotron radiation-total reflection X-ray fluorescence

    Science.gov (United States)

    López, María L.; Ceppi, Sergio A.; Asar, María L.; Bürgesser, Rodrigo E.; Ávila, Eldo E.

    2015-11-01

    Total reflection X-ray fluorescence analysis excited with synchrotron radiation was used to quantify the elemental concentration of rainwater in Córdoba, Argentina. Standard solutions with gallium as internal standard were prepared for the calibration curves. Rainwater samples of 5 μl were added to an acrylic reflector, allowed to dry, and analyzed for 200 s measuring time. The elemental concentrations of As, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, S, Sr, V, and Zn were determined. The electrical conductivity, pH, and elemental concentrations were compared to data previously reported for the soluble fraction of rainwater at different sites. A factor analysis was performed in order to determine the sources that contributed to the elemental concentration in rainwater. Anthropogenic sources were identified as traffic pollution, vehicular emissions, and metallurgical factories. The quality of rainwater was analyzed by comparing the concentrations of all the elements in rainwater samples with the WHO guideline values for drinking water. The results show the need to control the atmospheric emissions in order to preserve the quality of rainwater. SR-TXRF analysis of chemical composition of rainwater in Córdoba represents the very first contribution in the region to the knowledge of the concentration of trace metals in the soluble fraction of rainwater. These data are scarce, especially in the Southern Hemisphere.

  6. A review of standardization issues for total reflection X-ray fluorescence and vapor phase decomposition/total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Hockett, R.S.

    1995-01-01

    Total reflection X-ray fluorescence (TXRF) and vapor phase decomposition (VPD) followed by TXRF have become widespread methods for measuring surface metal contamination on silicon wafers. For quantification, TXRF and VPD/TXRF require reference samples. Since the approaches to making and using these reference samples have significantly varied among TXRF manufacturers and users worldwide, there exists some confusion about the quantification of TXRF and VPD/TXRF. This paper summarizes the basic issues behind TXRF and VPD/TXRF quantification using reference samples. (author)

  7. 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)

  8. Comprehensive approach to the validation of the standard method for total reflection X-ray fluorescence analysis of water.

    Science.gov (United States)

    Borgese, Laura; Dalipi, Rogerta; Riboldi, Alessandro; Bilo, Fabjola; Zacco, Annalisa; Federici, Stefania; Bettinelli, Maurizio; Bontempi, Elza; Depero, Laura Eleonora

    2018-05-01

    In this work, we present the validation of the chemical method for total reflection X-ray fluorescence (TXRF) analysis of water, proposed as a standard to the International Standard Organization. The complete experimental procedure to define the linear calibration range, elements sensitivities, limits of detection and quantification, precision and accuracy is presented for a commercial TXRF spectrometer equipped with Mo X-ray tube. Least squares linear regression, including all statistical tests is performed separately for each element of interest to extract sensitivities. Relative sensitivities with respect to Ga, as internal standard, are calculated. Accuracy and precision of the quantification procedure using Ga as internal standard is evaluated with reference water samples. A detailed discussion on the calibration procedure and the limitation of the use of this method for quantitative analysis of water is presented. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Monte Carlo simulation applied in total reflection x-ray fluorescence: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Meira, Luiza L. C.; Inocente, Guilherme F.; Vieira, Leticia D.; Mesa, Joel [Departamento de Fisica e Biofisica - Instituto de Biociencias de Botucatu, Universidade Estadual Paulista Julio de Mesquita Filho (Brazil)

    2013-05-06

    The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method.

  10. Monte Carlo simulation applied in total reflection x-ray fluorescence: Preliminary results

    Science.gov (United States)

    Meira, Luiza L. C.; Inocente, Guilherme F.; Vieira, Letícia D.; Mesa, Joel

    2013-05-01

    The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method.

  11. Direct analysis of Al2O3 powders by total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Peschel, Birgit U; Fittschen, Ursula E A; Pepponi, Giancarlo; Jokubonis, Christoph; Streli, Christina; Wobrauschek, Peter; Falkenberg, Gerald; Broekaert, José A C

    2005-08-01

    A direct analysis procedure for the determination of trace impurities of Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga in Al2O3 ceramic powders by total reflection X-ray fluorescence spectrometry (TXRF) is described. The powders were analysed in the form of slurries containing 1-10 mg mL(-1) of powder. The use of the procedure in the case of powders with differing grain size and for different slurry concentrations was investigated. Three different quantification possibilities were compared, namely the use of Al as a matrix component, the use of Fe as a trace element contained in the sample or of Co added in concentrations of 200 microg g(-1) as internal standard. The homogeneity of elemental distributions in sample layers deposited on the TXRF quartz carriers by evaporating 5 microL of the 10 mg mL(-1) slurries was studied by scanning the 4- to 5-mm-diameter spots of two samples by synchrotron radiation TXRF at Hasylab. For powders with differing graininess but mainly finer than about a few 10 microm, no systematic influence of the grain size on the accuracy of the determinations of Ca, V, Fe, Ni, Cu and Zn could be observed. The measurement precision, however, seemed to be limited by inhomogeneous distributions of the trace elements in the samples as testified by the synchrotron radiation TXRF scans. Detection limits of the developed TXRF procedure for Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga were found to be in the 0.3-7 microg g(-1) range and were shown to increase slightly with the grain size of the samples. Quantification using Al (matrix) as internal standard led to systematically higher values out of the accuracy required, whereas the other two approaches in all cases led to reliable results.

  12. Internal rulers to assess fluorescent protein photoactivation efficiency.

    Science.gov (United States)

    Renz, Malte; Wunder, Christian

    2017-12-29

    Photoactivatable fluorescent proteins (PA-FPs) have been widely used to assess the dynamics of cell biological processes. In addition, PA-FPs enabled single-molecule based super-resolution imaging (photoactivated localization microscopy) and thereby provided unprecedented structural insight. For the lack of tools, however, the fraction of PA-FPs that is, actually being switched on to fluoresce, that is, the photoactivation efficiency, has been difficult to assess. Uncertainty about photoactivation efficiency has hampered an understanding of the absolute amount of PA-FPs, that is, being examined. Here, we present internal rulers to assess photoactivation efficiencies of photoactivatable proteins. These internal rulers comprise a PA-FP that is genetically directly coupled to a spectrally distinct always-on fluorescent protein. Thus, these fluorescent proteins will be expressed in the bacterial and mammalian cell in a one-to-one ratio. With these tools, we describe photoactivation efficiencies of PA-GFP and PA-Cherry in intensity-based ratiometric ensemble studies and on the single-molecule level. In ratiometric ensemble studies, we show that photoactivation efficiency depends on how the PA-FPs are exposed to 405 nm light. Using a laser-scanning microscope, hundreds of iterative low-level exposures are up to four times more efficient than a short high-power exposure. Using wide-field illumination, photoactivation was similarly efficient and instantaneous. These findings suggest that the repetitive or stochastic exposure to photons of 405 nm light results in more efficient photoactivation than a continuous flow of photons. Because of the differential photoactivation efficiency, it is crucial to assess photoactivation efficiency for any given experimental set-up. The tools we provide can be applied to any genetically encoded photoactivatable protein. Determination of photoactivation efficiency is essential for an understanding of absolute molecule numbers in ensemble

  13. Portable total reflection X-ray fluorescence spectrometer for nanogram Cr detection limit.

    Science.gov (United States)

    Kunimura, Shinsuke; Kawai, Jun

    2007-03-15

    A portable total reflection X-ray fluorescence spectrometer is presented. The present spectrometer mainly consists of a 1.5-W X-ray tube, a waveguide type slit, a detector, and a sample carrier (a quartz optical flat), and these components are contained in an attache case-type box. Continuum X-rays emitted from the low-power X-ray tube are used for the excitation of the X-ray fluorescence, and the minimum detection limit for Cr is a few nanograms or the level of 1013 atoms/cm2.

  14. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces. Abaxial surfaces also produced higher reflectances, in general, in the 400-800 nm spectrum.

  15. Abstracts of the 8th Conference on total reflection x-ray fluorescence analysis and related methods

    International Nuclear Information System (INIS)

    Wobrauschek, P.

    2000-01-01

    The 8. conference on total reflection x-ray fluorescence analysis and related methods held from 25.9 to 29.9.2000 contains 79 abstracts about x-ray fluorescence analysis (XRFA) as a powerful tool used for industrial production, geological prospecting and for environmental control. Total reflection x-ray fluorescence spectroscopy is also a tool used for chemical analysis in medicine, industry and research. (E.B.)

  16. Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2008-01-01

    Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples

  17. Laboratory total reflection X-ray fluorescence analysis for low concentration samples

    Energy Technology Data Exchange (ETDEWEB)

    Hampai, D. [INFN-LNF, XLab Frascati, Via E. Fermi, 40, Frascati I-00044 (Italy); Dabagov, S.B. [INFN-LNF, XLab Frascati, Via E. Fermi, 40, Frascati I-00044 (Italy); RAS P.N. Lebedev Phys. Inst. and Nat. Res. Nucl. Univ. MEPhI Moscow (Russian Federation); Polese, C. [INFN-LNF, XLab Frascati, Via E. Fermi, 40, Frascati I-00044 (Italy); Dip. DICMA, Univ. Roma “Sapienza”, Via Eudossiana 18, Rome (Italy); Liedl, A. [INFN-LNF, XLab Frascati, Via E. Fermi, 40, Frascati I-00044 (Italy); Dip. Scienze Geologiche, Univ. Roma3, Largo San Leonardo Murialdo 1, Rome (Italy); Cappuccio, G. [INFN-LNF, XLab Frascati, Via E. Fermi, 40, Frascati I-00044 (Italy)

    2014-11-01

    Quantitative elemental determination for concentrations in the ppb range requires a careful preparation of the sample. In particular, for elemental analysis of very low concentration samples, less than 1 ng/mm{sup 2}, a very bright X-ray source, typically synchrotron radiation (SR) in total external reflection fluorescence regime (SR-TXRF), is required. Here, we wish to demonstrate that a conventional source combined with a polycapillary semi-lens can provide a quasi-parallel beam intense enough for desktop TXRF analysis of low concentration samples. - Highlights: • Total Reflection X-ray Fluorescence for very low concentration analisys. • Qualitative and quantitative information from trace elements in the ppb range. • Conventional source with polycapillary optics instead Synchrotron Radiation. • Possibility to perform the technique in all kind of laboratories.

  18. Considerations on the ideal sample shape for Total Reflection X-ray Fluorescence Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Horntrich, C., E-mail: chorn@ati.ac.at; Kregsamer, P.; Wobrauschek, P.; Streli, C.

    2011-11-15

    Total Reflection X-ray Fluorescence analysis (TXRF) is widely used in semiconductor industry for the analysis of silicon wafer surfaces. Typically an external standard is used for the calibration of the spectrometer. This is sensitive to errors in quantification. For small sample amounts the thin film approximation is valid, absorption effects of the exciting and the detected radiation are neglected and the relation between sample amount and fluorescence intensity is linear. For higher total sample amounts deviations from linearity have been observed (saturation effect). These deviations are one of the difficulties for external standard quantification. A theoretical determination of the ideal TXRF sample shape is content of the presented work with the aim to improve the calibration process and therefore the quantification. The fluorescence intensity emitted by different theoretical sample shapes was calculated, whereby several parameters have been varied (excitation energy, density, diameter/height ratio of the sample). It was investigated which sample shape leads to the highest fluorescence intensity and exhibits the lowest saturation effect. The comparison of the different sample shapes showed that the ring shape matches the ideal TXRF sample shape best. - Highlights: Black-Right-Pointing-Pointer In this work the ideal TXRF sample shape is theoretically determined. Black-Right-Pointing-Pointer Different theoretical sample shapes were investigated. Black-Right-Pointing-Pointer The ring shape matches the ideal TXRF sample shape best. Black-Right-Pointing-Pointer It leads to the highest fluorescence intensity and the lowest saturation effect.

  19. The internalization of fluorescence-labeled PLA nanoparticles by macrophages.

    Science.gov (United States)

    Li, Fengjuan; Zhu, Aiping; Song, Xiaoli; Ji, Lijun; Wang, Juan

    2013-09-10

    Rhodamine B (RhB)-labeled PLA nanoparticles were prepared through surface grafting copolymerization of glycidyl methacrylate (GMA) onto PLA nanoparticles during the emulsion/evaporation process. RhB firstly interacts with sodium dodecyl sulfate (SDS) through electrostatic interaction to form hydrophobic complex (SDS-RhB). Due to the high-affinity of SDS-RhB with GMA, hydrophilic RhB can be successfully combined into PLA nanoparticles. The internalization of RhB-labeled PLA nanoparticles by macrophages was investigated with fluorescence microscope technology. The effects of the PLA nanoparticle surface nature and size on the internalization were investigated. The results indicate that the PLA particles smaller than 200 nm can avoid the uptake of phagocytosis. The bigger PLA particles (300 nm) with polyethylene glycol (PEG) surface showed less internalization by macrophage compared with those with poly(ethylene oxide-propylene oxide) copolymer (F127) or poly(vinyl alcohol) (PVA) surface. The "stealth" function of PEG on the PLA nanoparticles from internalization of macrophages due to the low protein adsorption is revealed by electrochemical impedance technology. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Maintaining International Peace and Security: Reflections on Peace ...

    African Journals Online (AJOL)

    Maintaining International Peace and Security: Reflections on Peace-Support Operations in Africa. DR THEO NEETHLING. Centrefor Military Studies, University of Stellenbosch. ABSTRACT. The shift from a bipolar to a multipolar and multi-faceted world has reduced the risk of conventional inter-state wars, but has been the ...

  1. Revisit: A Surprising Demonstration of Total Internal Reflection

    Science.gov (United States)

    Lee, Jiwon; Cha, Yu Wha; Jung, Yeon Su; Oh, Eun Ju; Moon, Ye Lin; Kim, Jung Bog

    2016-01-01

    Melton demonstrated a surprising disappearance using total internal reflection. When he put a Florence flask filled with marbles into a water tank and looked straight down from directly above the flask, he was only able to see marbles above a certain water level. When he added more water into the tank above the top line of the marbles, all of the…

  2. Gaining Insight into Antibubbles via Frustrated Total Internal Reflection

    Science.gov (United States)

    Suhr, Wilfried

    2012-01-01

    The interest in the phenomenon of frustrated total internal reflection dates back to the time of Newton. Because of its technological relevance, it has become a standard topic covered by advanced courses in physics. In practical courses optical setups especially designed to demonstrate the phenomenon are commonly used. As an alternative, this…

  3. Double conoscopic figures in total-internal-reflection prisms

    Science.gov (United States)

    Litvinova, M. N.; Stroganov, V. I.; Krishtop, V. V.; Alekseeva, L. V.; Pas'ko, P. G.

    2006-01-01

    This paper presents the results of a study of the features of the formation of double conoscopic figures in total-internal-reflection prisms. The conditions for the existence of double conoscopic figures in the absence of a polarizer and analyzer are explained. An experiment has been done with prisms fabricated from crystals of calcite, potassium dihydrogen phosphate (KDP) and lithium niobate.

  4. International Student Teaching: Stimulus for Developing Reflective Teachers.

    Science.gov (United States)

    Vall, Nancy Gerdin, Tennison, Jo M.

    1992-01-01

    Discusses how culture shock intrinsic in a cross-cultural student teaching experience necessitates that participants think critically and reflect about teaching. The article describes an international student teaching component at two Minnesota colleges. After 7 weeks of student teaching in the United States, participants spend 6 weeks in British…

  5. Chlorophyll Fluorescence Emissions of Vegetation Canopies From High Resolution Field Reflectance Spectra

    Science.gov (United States)

    Middleton, E. M.; Corp, L. A.; Daughtry, C. S. T.; Campbell, P. K. Entcheva

    2006-01-01

    A two-year experiment was performed on corn (Zea mays L.) crops under nitrogen (N) fertilization regimes to examine the use of hyperspectral canopy reflectance information for estimating chlorophyll fluorescence (ChlF) and vegetation production. Fluorescence of foliage in the laboratory has proven more rigorous than reflectance for correlation to plant physiology. Especially useful are emissions produced from two stable red and far-red chlorophyll ChlF peaks centered at 685V10 nm and 735V5 nm. Methods have been developed elsewhere to extract steady state solar induced fluorescence (SF) from apparent reflectance of vegetation canopies/landscapes using the Fraunhofer Line Depth (FLD) principal. Our study utilized these methods in conjunction with field-acquired high spectral resolution canopy reflectance spectra obtained in 2004 and 2005 over corn crops, as part of an ongoing multi-year experiment at the USDA/Agriculture Research Service in Beltsville, MD. A spectroradiometer (ASD-FR Fieldspec Pro, Analytical Spectral Devices, Inc., Boulder, CO) was used to measure canopy radiances 1 m above plant canopies with a 22deg field of view and a 0deg nadir view zenith angle. Canopy and plant measurements were made at the R3 grain fill reproductive stage on 3-4 replicate N application plots provided seasonal inputs of 280, 140, 70, and 28 kg N/ha. Leaf level measurements were also made which included ChlF, photosynthesis, and leaf constituents (photosynthetic pigment, carbon (C), and N contents). Crop yields were determined at harvest. SIF intensities for ChlF were derived directly from canopy reflectance spectra in specific narrowband regions associated with atmospheric oxygen absorption features centered at 688 and 760 nm. The red/far-red S F ratio derived from these field reflectance spectra successfully discriminated foliar pigment levels (e.g., total chlorophyll, Chl) associated with N application rates in both corn crops. This canopy-level spectral ratio was also

  6. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

  7. Generally Applicable Transformation Protocols for Fluorescent Nanodiamond Internalization into Cells

    NARCIS (Netherlands)

    Hemelaar, Simon R; van der Laan, Kiran J; Hinterding, Sophie R; Koot, Manon V; Ellermann, Else; Perona-Martinez, Felipe P; Roig, David; Hommelet, Severin; Novarina, Daniele; Takahashi, Hiroki; Chang, Michael; Schirhagl, Romana

    2017-01-01

    Fluorescent nanodiamonds (FNDs) are promising nanoprobes, owing to their stable and magnetosensitive fluorescence. Therefore they can probe properties as magnetic resonances, pressure, temperature or strain. The unprecedented sensitivity of diamond defects can detect the faint magnetic resonance of

  8. Single particle transfer for quantitative analysis with total-reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

    2006-01-01

    The technique of single particle transfer was applied to quantitative analysis with total-reflection X-ray fluorescence (TXRF) spectrometry. The technique was evaluated by performing quantitative analysis of individual Cu particles with diameters between 3.9 and 13.2 μm. The direct quantitative analysis of the Cu particle transferred onto a Si carrier gave a discrepancy between measured and calculated Cu amounts due to the absorption effects of incident and fluorescent X-rays within the particle. By the correction for the absorption effects, the Cu amounts in individual particles could be determined with the deviation within 10.5%. When the Cu particles were dissolved with HNO 3 solution prior to the TXRF analysis, the deviation was improved to be within 3.8%. In this case, no correction for the absorption effects was needed for quantification

  9. Multielemental analysis in Brazilian cigarettes using total reflection X-ray fluorescence with synchrotron radiation

    International Nuclear Information System (INIS)

    Serpa, Renata F.B.; Jesus, Edgar F.O. de; Lopes, Ricardo T.; Moreira, Silvana

    2005-01-01

    In order to identify major and trace elements in conventional and light Brazilian cigarettes, Total Reflection X-Ray Fluorescence with Synchrotron Radiation (SR-TXRF) was used. The fluorescence measurements were carried out at Brazilian Synchrotron Light Laboratory, Campinas - Sao Paulo. This technique enables detection limit is in the ngg -1 range, which is very useful in elemental tobacco smoke analysis, since it presents most of its elements at a trace level. The major elements identified in tobacco samples were: S, Cl, K, Ca, Mn, Fe and Cd, and the trace elements were: Ti, Cr, Ni, Cu, Zn, Br, Rb, Sr and Ba. However in tobacco smoke samples, there were only two major elements: K and Ca, the others were present a trace level. The rate transfer of tobacco to tobacco smoke was about 2.5 % for all elements studied. (author)

  10. Application of total reflection X-ray fluorescence spectrometry to small glass fragments.

    Science.gov (United States)

    Nishiwaki, Yoshinori; Shimoyama, Masahiko; Nakanishi, Toshio; Ninomiya, Toshio; Nakai, Izumi

    2006-10-01

    Total reflection X-ray fluorescence spectrometry (TXRF) has been applied for trace elemental analysis of small glass fragments. A small glass sample (a fragment with weight less than 0.5 mg) was decomposed by 100 microg of HF/HNO3 acid; the material was condensed to 10 microl and was dried on a Si wafer. Since the size of the dried residue on the Si wafer was less than 1 cm in diameter, an incident X-ray beam with about 1 cm in width could effectively excite elemental components in such a small glass fragment. The precision of the present technique was checked by analyzing the glass fragments (forensic discrimination. Comparison of five elemental ratios of Ti/Sr, Mn/Sr, Zn/Sr, Rb/Sr, and Pb/Sr calculated from X-ray fluorescence spectra was effective in distinguishing glass fragments that could not be differentiated by their refractive indexes (RI).

  11. New prism ring laser design incorporating frustrated total internal reflection output coupling

    DEFF Research Database (Denmark)

    Heyde, C.; Hansen, P.L.; Buchhave, Preben

    1997-01-01

    A novel prism ring laser design incorporating total internal reflection resonator mirrors and frustrated total internal reflection output coupling is analyzed and tested experimentally.......A novel prism ring laser design incorporating total internal reflection resonator mirrors and frustrated total internal reflection output coupling is analyzed and tested experimentally....

  12. Application of a portable total reflection x-ray fluorescence spectrometer to a trace elemental analysis of wines

    International Nuclear Information System (INIS)

    Kunimura, Shinsuke; Kawai, Jun

    2009-01-01

    A portable total reflection X-ray fluorescence (TXRF) spectrometer has been applied to a trace elemental analysis of wines. Sulfur, K, Mn, Fe, and Rb were detected. These five elements were quantified by using 1 ppm of Co as an internal standard. The quantified concentrations ranged from sub-ppm to several hundred ppm. Because of organic substances in wines, the scattering of the incident X-rays from the dry residues of wines becomes strong. Therefore, a high spectral background appears in TXRF spectra of wines. Because of this background, relative standard deviations of the quantified concentrations were from 4 to 28%. Although the high spectral background appeared in the TXRF spectra of the wines, a detection limit down to several tens of ppb was achieved. The present portable spectrometer can be applied to screening for trace elements in wines before an accurate and precise analysis using a large elemental analyzer. (author)

  13. Trace Elemental Determination Using a Portable Total Reflection X-Ray Fluorescence Spectrometer with a Collodion Film Sample Holder.

    Science.gov (United States)

    Kunimura, Shinsuke; Shinkai, Tomoki

    2017-01-01

    Using a portable total-reflection X-ray fluorescence (TXRF) spectrometer with a collodion film sample holder, a spectrum of an analyte containing 50 ng of aluminum was measured. The Al Kα line (1.49 keV) that partially overlaps with the Si Kα line (1.74 keV) from a quartz glass substrate usually used as a sample holder for TXRF analysis, was clearly detected when using the collodion film sample holder. To investigate the quantitative performance of the portable spectrometer with a collodion film sample holder, the concentrations of Cr, Mn, and Fe in a certified reference material of river water (JSAC 0302-3b), whose certified values are 10.0, 5.1, and 59.6 μg/L, respectively, were determined by the internal-standard method. We showed that approximate concentrations of these elements were determined.

  14. Determination of heavy metals in Damascus drinking water using total reflection x-ray fluorescence

    International Nuclear Information System (INIS)

    Bakraji, E. H.; Karajo, J.

    2000-01-01

    Total reflection x-ray fluorescence spectrometry and chemical preconcentration have applied for multi-elemental analysis of Damascus drinking water. Water was taken directly from taps of several city sectors and analyzed for the following trace elements: Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Se and Pb. The detection limits were found to be in the range of 0.1 to 0.4 μg/l. The mean levels of trace elements in the Damascus drinking water were below the World Health Organization drinking water quality guidelines. (author)

  15. Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2

    Science.gov (United States)

    Tiwari, M. K.; Singh, A. K.; Das, Gangadhar; Chowdhury, Anupam; Lodha, G. S.

    2014-04-01

    Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

  16. Laboratory total reflection X-ray fluorescence analysis for low concentration samples

    Science.gov (United States)

    Hampai, D.; Dabagov, S. B.; Polese, C.; Liedl, A.; Cappuccio, G.

    2014-11-01

    Quantitative elemental determination for concentrations in the ppb range requires a careful preparation of the sample. In particular, for elemental analysis of very low concentration samples, less than 1 ng/mm2, a very bright X-ray source, typically synchrotron radiation (SR) in total external reflection fluorescence regime (SR-TXRF), is required. Here, we wish to demonstrate that a conventional source combined with a polycapillary semi-lens can provide a quasi-parallel beam intense enough for desktop TXRF analysis of low concentration samples.

  17. Note: Portable total reflection X-ray fluorescence spectrometer with small vacuum chamber

    Science.gov (United States)

    Kunimura, Shinsuke; Kudo, Shunpei; Nagai, Hiroki; Nakajima, Yoshihide; Ohmori, Hitoshi

    2013-04-01

    To improve the detection limits of a portable total reflection X-ray fluorescence (TXRF) spectrometer using white X-rays (i.e., both characteristic X-rays and continuum X-rays) from a 5 W X-ray tube, the measurement was performed in vacuum. The TXRF spectrum measured in vacuum was compared with that measured in air. The spectral background was significantly reduced when the scattering of the incident X-rays from air was reduced using a vacuum pump, leading to improvement in the detection limit. A detection limit of 8 pg was achieved for Cr when measuring in vacuum.

  18. First Total Reflection X-Ray Fluorescence round-robin test of water samples: Preliminary results

    Science.gov (United States)

    Borgese, Laura; Bilo, Fabjola; Tsuji, Kouichi; Fernández-Ruiz, Ramón; Margui, Eva; Streli, Christina; Pepponi, Giancarlo; Stosnach, Hagen; Yamada, Takashi; Vandenabeele, Peter; Maina, David M.; Gatari, Michael; Shepherd, Keith D.; Towett, Erick K.; Bennun, Leonardo; Custo, Graciela; Vasquez, Cristina; Depero, Laura E.

    2014-11-01

    Total Reflection X-Ray Fluorescence (TXRF) is a mature technique to evaluate quantitatively the elemental composition of liquid samples deposited on clean and well polished reflectors. In this paper the results of the first worldwide TXRF round-robin test of water samples, involving 18 laboratories in 10 countries are presented and discussed. The test was performed within the framework of the VAMAS project, interlaboratory comparison of TXRF spectroscopy for environmental analysis, whose aim is to develop guidelines and a standard methodology for biological and environmental analysis by means of the TXRF analytical technique.

  19. Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, M. K., E-mail: mktiwari@rrcat.gov.in; Singh, A. K., E-mail: mktiwari@rrcat.gov.in; Das, Gangadhar, E-mail: mktiwari@rrcat.gov.in; Chowdhury, Anupam, E-mail: mktiwari@rrcat.gov.in; Lodha, G. S., E-mail: mktiwari@rrcat.gov.in [Indus Synchrotrons Utilisation Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

    2014-04-24

    Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

  20. Note: Portable total reflection X-ray fluorescence spectrometer with small vacuum chamber.

    Science.gov (United States)

    Kunimura, Shinsuke; Kudo, Shunpei; Nagai, Hiroki; Nakajima, Yoshihide; Ohmori, Hitoshi

    2013-04-01

    To improve the detection limits of a portable total reflection X-ray fluorescence (TXRF) spectrometer using white X-rays (i.e., both characteristic X-rays and continuum X-rays) from a 5 W X-ray tube, the measurement was performed in vacuum. The TXRF spectrum measured in vacuum was compared with that measured in air. The spectral background was significantly reduced when the scattering of the incident X-rays from air was reduced using a vacuum pump, leading to improvement in the detection limit. A detection limit of 8 pg was achieved for Cr when measuring in vacuum.

  1. Environmental trace-element analysis using a benchtop total reflection X-ray fluorescence spectrometer.

    Science.gov (United States)

    Stosnach, Hagen

    2005-07-01

    Total reflection X-ray fluorescence (TXRF) analysis is an established technique for trace-element analysis in various types of samples. Though expensive large-scale systems restricted the applications in the past, in this study the capability of a benchtop system for trace elemental analysis is reported. The suitability of this system for the mobile on-site analysis of heavy metal contaminated soils and sediments is reported as well as the possibilities and restrictions of TXRF for additional applications, including trace-element analysis of water, glass and biological samples.

  2. Determination of metal-ligand stoichiometries for inorganic complexes using total reflection X-ray fluorescence.

    Science.gov (United States)

    Greaves, E D; Bennun, L; Gomez, J; Nemeth, P; Sajo-Bohus, L

    The methods usually used to determine the ratio metal-ligand in inorganic complexes require a set of solutions with different concentrations for both the ligand and metal. We propose a new method using the total reflection X-ray fluorescence technique, in which the ratio between metal and ligand is determined precisely, easily, and quickly. Experimental results provide evidence that for different chemical complexes, the ligand-metal ratio determined by this technique deviates at most from stoichiometric values by 6%. The technique is restricted usually to elements with Z above 14, and its detection limit is on the order of 10(-8) g/g.

  3. Using remotely sensed spectral reflectance to indicate leaf photosynthetic efficiency derived from active fluorescence measurements

    Science.gov (United States)

    Peng, Yi; Zeng, Aoli; Zhu, Tinge; Fang, Shenghui; Gong, Yan; Tao, Yanqi; Zhou, Ying; Liu, Kan

    2017-04-01

    Chlorophyll fluorescence (ChlF) is an important signature of photosynthesis to evaluate plant response to the environment. We explored an approach to estimate an important leaf ChlF-derived parameter, the intrinsic efficiency of photosystem II photochemistry (Fv/Fm), using spectral indices calculated from leaf reflectance measured by a hyperspectral radiometer. It is observed that leaf chlorophyll content closely related to Fv/Fm in nonstressed leaves, thus the indices developed for chlorophyll estimation were successfully used to estimate Fv/Fm. For leaves under short-term stress, Fv/Fm dropped dramatically while leaf chlorophyll content remained almost the same. Compared to leaf chlorophyll content, reflectance was more sensitive to Fv/Fm variations. As Fv/Fm decreased, the slope of reflectance in the spectrum range of 700 to 900 nm obviously increased, and the first derivative reflectance in the red edge and infrared (NIR) regions was highly correlated with Fv/Fm. The indices using longwave red edge and NIR reflectance (NDRE740 and CI740) worked well for Fv/Fm retrieval in both stressed and nonstressed leaves with the coefficients of determination (R2) above 0.72 and normalized root-mean-square errors below 0.16. Note that the relationships NDRE740 and CI740 versus Fv/Fm were significantly different between nonstressed and stressed leaves, which may give a good implication to detect short-term stress occurrence.

  4. Different size biomolecules anchoring on porous silicon surface: fluorescence and reflectivity pores infiltration comparative studies

    Energy Technology Data Exchange (ETDEWEB)

    Giovannozzi, Andrea M.; Rossi, Andrea M. [National Institute for Metrological Research, Thermodynamic Division, Strada delle Cacce 91, 10135 Torino (Italy); Renacco, Chiara; Farano, Alessandro [Ribes Ricecrhe Srl, Via Lavoratori Vittime del Col du Mont 24, 11100 Aosta (Italy); Derosas, Manuela [Biodiversity Srl, Via Corfu 71, 25124 Brescia (Italy); Enrico, Emanuele [National Institute for Metrological Research, Electromagnetism Division, Strada delle Cacce 91, 10135 Torino (Italy)

    2011-06-15

    The performance of porous silicon optical based biosensors strongly depends on material nanomorphology, on biomolecules distribution inside the pores and on the ability to link sensing species to the pore walls. In this paper we studied the immobilization of biomolecules with different size, such as antibody anti aflatoxin (anti Aflatox Ab, {proportional_to}150 KDa), malate dehydrogenase (MDH, {proportional_to}36KDa) and metallothionein (MT, {proportional_to}6KDa) at different concentrations on mesoporous silicon samples ({proportional_to}15 nm pores diameter). Fluorescence measurements using FITC- labeled biomolecules and refractive index analysis based on reflectivity spectra have been employed together to detect the amount of proteins bound to the surface and to evaluate their diffusion inside the pores. Here we suggest that these two techniques should be used together to have a better understanding of what happens at the porous silicon surface. In fact, when pores dimensions are not perfectly tuned to the protein size a higher fluorescence signal doesn't often correspond to a higher biomolecules distribution inside the pores. When a too much higher concentration of biomolecule is anchored on the surface, steric crowd effects and repulsive interactions probably take over and hinder pores infiltration, inducing a small or absent shift in the fringe pattern even if a higher fluorescence signal is registered. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Automated Cart with VIS/NIR Hyperspectral Reflectance and Fluorescence Imaging Capabilities

    Directory of Open Access Journals (Sweden)

    Alan M. Lefcourt

    2016-12-01

    Full Text Available A system to take high-resolution Visible/Near Infra-Red (VIS/NIR hyperspectral reflectance and fluorescence images in outdoor fields using ambient lighting or a pulsed laser (355 nm, respectively, for illumination purposes was designed, built, and tested. Components of the system include a semi-autonomous cart, a gated-intensified camera, a spectral adapter, a frequency-triple Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet laser, and optics to convert the Gaussian laser beam into a line-illumination source. The front wheels of the cart are independently powered by stepper motors that support stepping or continuous motion. When stepping, a spreadsheet is used to program parameters of image sets to be acquired at each step. For example, the spreadsheet can be used to set delays before the start of image acquisitions, acquisition times, and laser attenuation. One possible use of this functionality would be to establish acquisition parameters to facilitate the measurement of fluorescence decay-curve characteristics. The laser and camera are mounted on an aluminum plate that allows the optics to be calibrated in a laboratory setting and then moved to the cart. The system was validated by acquiring images of fluorescence responses of spinach leaves and dairy manure.

  6. Production of the ideal sample shape for Total Reflection X-ray Fluorescence analysis

    Science.gov (United States)

    Horntrich, C.; Kregsamer, P.; Prost, J.; Stadlbauer, F.; Wobrauschek, P.; Streli, C.

    2012-11-01

    Total Reflection X-ray Fluorescence analysis (TXRF) is a well-established analytical method in the semiconductor industry for the analysis of silicon wafer surfaces. For the calibration of the spectrometer typically an external standard is used which is sensitive to quantification errors. In general TXRF is known to allow for linear calibration. For small sample amounts (pg to ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. For higher total amounts of sample the relation between fluorescence intensity and sample amount diverges from linearity (saturation effect). These deviations lead to difficulties in quantification with external standard. Content of the presented work is the production of the ideal TXRF sample shape, which was theoretically determined to be ring shaped. A possibility for the production of samples with ring shape is the use of a nanodispensing system combined with a positioning device. Therewith it is possible to produce ring shaped samples in a controlled way with the ring consisting of individual nanodroplets, so that the wanted diameter of the ring can be chosen. A comparison of the fluorescence intensities emitted by contracted and ring shaped samples shows that the ring shape is not only theoretically the best TXRF shape but also experimentally. It could be proven that for contracted samples the saturation effect occurs at a lower sample mass than for samples with ring shape.

  7. Portable total reflection x-ray fluorescence analysis in the identification of unknown laboratory hazards

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying, E-mail: liu.ying.48r@st.kyoto-u.ac.jp; Imashuku, Susumu; Sasaki, Nobuharu; Ze, Long; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Takano, Shotaro; Sohrin, Yoshiki [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Seki, Hiroko; Miyauchi, Hiroya [Kyoto Prefectural Technology Center for Small and Medium Enterprises, Chudojiminami machi, Shimogyo-ku, Kyoto 600-8813 (Japan)

    2014-05-15

    In this study, a portable total reflection x-ray fluorescence (TXRF) spectrometer was used to analyze unknown laboratory hazards that precipitated on exterior surfaces of cooling pipes and fume hood pipes in chemical laboratories. With the aim to examine the accuracy of TXRF analysis for the determination of elemental composition, analytical results were compared with those of wavelength-dispersive x-ray fluorescence spectrometry, scanning electron microscope and energy-dispersive x-ray spectrometry, energy-dispersive x-ray fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, x-ray diffraction spectrometry (XRD), and x-ray photoelectron spectroscopy (XPS). Detailed comparison of data confirmed that the TXRF method itself was not sufficient to determine all the elements (Z > 11) contained in the samples. In addition, results suggest that XRD should be combined with XPS in order to accurately determine compound composition. This study demonstrates that at least two analytical methods should be used in order to analyze the composition of unknown real samples.

  8. Total reflection X-ray fluorescence and archaeometry: Application in the Argentinean cultural heritage

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Cristina [Comision Nacional de Energia Atomica, Av. Gral Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina); Laboratorio de Quimica de Sistemas Heterogeneos, Facultad de Ingenieria, Universidad de Buenos Aires, P. Colon 850 (C1063ACU), Buenos Aires (Argentina)], E-mail: Cristina.Vazquez@cnea.gov.ar; Albornoz, Ana [Agencia Rio Negro Cultura, Museo de la Patagonia F.P.Moreno, Centro Civico s/n Bariloche, Rio Negro (Argentina); Hajduk, Adam [CONICET, Museo de la Patagonia F.P.Moreno, Centro Civico s/n Bariloche, Rio Negro (Argentina); Elkin, Dolores [CONICET Instituto Nacional de Antropologia y Pensamiento Latinoamericano, 3 de febrero 1378 (C1426AEL) Buenos Aires (Argentina); Custo, Graciela; Obrustky, Alba [Comision Nacional de Energia Atomica, Av. Gral Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina)

    2008-12-15

    Archaeometry is an interdisciplinary research area involved in the development and use of scientific methods in order to answer questions concerned with the human history. In this way the knowledge of archaeological objects through advanced chemical and physical analyses permits a better preservation and conservation of the cultural heritage and also reveals materials and technologies used in the past. In this sense, analytical techniques play an important role in order to provide chemical information about cultural objects. Considering the non destructive characteristic of this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Taking into account the irreplaceable character of the archaeological and artistic materials considered in this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Total Reflection X-ray Fluorescence Spectrometry as a geometric variant of conventional X-ray fluorescence is a proved microanalytical technique considering the small amount of sample required for the analysis. A few micrograms are enough in order to reveal valuable information about elemental composition and in this context it is highly recommended for artwork studies. In this paper a case study is presented in which Total Reflection X-Ray Fluorescence Spectrometry has been successfully employed in the archaeometry field. Examples from Argentinean cultural heritage sites related with the determination of pigments in paintings on canvas and in rock sites as well as in underwater archaeology research are shown.

  9. Total reflection X-ray fluorescence and archaeometry: Application in the Argentinean cultural heritage

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Albornoz, Ana; Hajduk, Adam; Elkin, Dolores; Custo, Graciela; Obrustky, Alba

    2008-01-01

    Archaeometry is an interdisciplinary research area involved in the development and use of scientific methods in order to answer questions concerned with the human history. In this way the knowledge of archaeological objects through advanced chemical and physical analyses permits a better preservation and conservation of the cultural heritage and also reveals materials and technologies used in the past. In this sense, analytical techniques play an important role in order to provide chemical information about cultural objects. Considering the non destructive characteristic of this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Taking into account the irreplaceable character of the archaeological and artistic materials considered in this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Total Reflection X-ray Fluorescence Spectrometry as a geometric variant of conventional X-ray fluorescence is a proved microanalytical technique considering the small amount of sample required for the analysis. A few micrograms are enough in order to reveal valuable information about elemental composition and in this context it is highly recommended for artwork studies. In this paper a case study is presented in which Total Reflection X-Ray Fluorescence Spectrometry has been successfully employed in the archaeometry field. Examples from Argentinean cultural heritage sites related with the determination of pigments in paintings on canvas and in rock sites as well as in underwater archaeology research are shown

  10. Reference-free total reflection X-ray fluorescence analysis of semiconductor surfaces with synchrotron radiation.

    Science.gov (United States)

    Beckhoff, Burkhard; Fliegauf, Rolf; Kolbe, Michael; Müller, Matthias; Weser, Jan; Ulm, Gerhard

    2007-10-15

    Total reflection X-ray fluorescence (TXRF) analysis is a well-established method to monitor lowest level contamination on semiconductor surfaces. Even light elements on a wafer surface can be excited effectively when using high-flux synchrotron radiation in the soft X-ray range. To meet current industrial requirements in nondestructive semiconductor analysis, the Physikalisch-Technische Bundesanstalt (PTB) operates dedicated instrumentation for analyzing light element contamination on wafer pieces as well as on 200- and 300-mm silicon wafer surfaces. This instrumentation is also suited for grazing incidence X-ray fluorescence analysis and conventional energy-dispersive X-ray fluorescence analysis of buried and surface nanolayered structures, respectively. The most prominent features are a high-vacuum load-lock combined with an equipment front end module and a UHV irradiation chamber with an electrostatic chuck mounted on an eight-axis manipulator. Here, the entire surface of a 200- or a 300-mm wafer can be scanned by monochromatized radiation provided by the plane grating monochromator beamline for undulator radiation in the PTB laboratory at the electron storage ring BESSY II. This beamline provides high spectral purity and high photon flux in the range of 0.078-1.86 keV. In addition, absolutely calibrated photodiodes and Si(Li) detectors are used to monitor the exciting radiant power respectively the fluorescence radiation. Furthermore, the footprint of the excitation radiation at the wafer surface is well-known due to beam profile recordings by a CCD during special operation conditions at BESSY II that allow for drastically reduced electron beam currents. Thus, all the requirements of completely reference-free quantitation of TXRF analysis are fulfilled and are to be presented in the present work. The perspectives to arrange for reference-free quantitation using X-ray tube-based, table-top TXRF analysis are also addressed.

  11. DIRC, the internally reflecting ring imaging Cherenkov detector for BABAR

    International Nuclear Information System (INIS)

    Adam, I.; Aston, D.

    1997-11-01

    The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design

  12. TX 2000: total reflection and 45o energy dispersive x-ray fluorescence spectrometer

    International Nuclear Information System (INIS)

    Pasti, F.; Torboli, A.; Valdes, M.

    2000-01-01

    This equipment, developed by Ital Structures, combines two kinds of energy dispersive X-ray fluorescence techniques, the first using total reflection geometry and the second conventional 45 o geometry. The equipment is completely controlled by a PC and to reach the condition of total reflection is very easy because it is enough to load the file with the right position for the corresponding energy. In this apparatus we used an x-ray tube with an alloy anode of Mo/W with a long fine focus at 2200 W. To monochromatize the x-ray beam while choosing, for example, the Mo K alpha or W L alpha or a piece of white spectrum of 33 keV, we use a highly reflective multilayer made of Si/W with 2d = 45.5 A o . The detector used in the equipment is a lithium drifted silicon detector (Si(Li)) with an excellent energy resolution of 135 eV at 5.9 keV and 1000 cps. We developed two programs written in Windows 95, 98 and NT for a 32 bit microprocessor. The first one is called TYACQ32 and has the following functions: first, complete control of the hardware, second automatic alignment of the TX 2000 spectrometer and third acquisition of spectra. The second program is EDXRF32. This is a program to accomplish spectrum and quantitative analysis for TXRF and EDXRF 45 o degrees analysis. (author)

  13. Laser-induced fluorescence measurement of the oil film thickness in an internal combustion engine

    Science.gov (United States)

    Ostroski, Greg M.; Ghandhi, Jaal B.

    1997-11-01

    The use of a fluorescent dopant molecule to enhance the natural fluorescence of motor oils, and allow quantitative determination of temperature and film thickens in internal combustion engines has been investigated. Measurement of the fluorescence as a function of temperature were made with neat Mobil 1, and solutions of the dopant BTBP in mineral oil and Mobil 1. The fluorescence yield of neat Mobil 1 was found to vary by 30 percent over the temperature range explored, but the spectral characteristics, as measured with bandpass filters, were unaffected by temperature. The BTBP fluorescence was found to increase significantly with temperature, and it was found the narrower regions in the spectrum increased proportionally more than the fluorescence collected over the entire spectrum, allowing a determination of temperature to be made which can then be used to correct for the change in fluorescence yield. Solutions in Mobil 1 showed a smaller increase than that observed in mineral oil.

  14. Production of the ideal sample shape for Total Reflection X-ray Fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Horntrich, C., E-mail: chorn@ati.ac.at [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Kregsamer, P.; Prost, J. [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Stadlbauer, F. [Institut fuer Werkstoffwissenschaft und Werkstofftechnologie, Vienna University of Technology, 1040 Wien (Austria); Wobrauschek, P.; Streli, C. [Atominstitut, Vienna University of Technology, 1020 Wien (Austria)

    2012-11-15

    Total Reflection X-ray Fluorescence analysis (TXRF) is a well-established analytical method in the semiconductor industry for the analysis of silicon wafer surfaces. For the calibration of the spectrometer typically an external standard is used which is sensitive to quantification errors. In general TXRF is known to allow for linear calibration. For small sample amounts (pg to ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. For higher total amounts of sample the relation between fluorescence intensity and sample amount diverges from linearity (saturation effect). These deviations lead to difficulties in quantification with external standard. Content of the presented work is the production of the ideal TXRF sample shape, which was theoretically determined to be ring shaped. A possibility for the production of samples with ring shape is the use of a nanodispensing system combined with a positioning device. Therewith it is possible to produce ring shaped samples in a controlled way with the ring consisting of individual nanodroplets, so that the wanted diameter of the ring can be chosen. A comparison of the fluorescence intensities emitted by contracted and ring shaped samples shows that the ring shape is not only theoretically the best TXRF shape but also experimentally. It could be proven that for contracted samples the saturation effect occurs at a lower sample mass than for samples with ring shape. - Highlights: Black-Right-Pointing-Pointer The ring shape was found to be the theoretically ideal TXRF sample in a former study. Black-Right-Pointing-Pointer A nanodispensing system enables the production of ring shaped samples. Black-Right-Pointing-Pointer Contracted and ring shaped samples were compared. Black-Right-Pointing-Pointer The ring shape was also experimentally proven to be the best TXRF shape.

  15. Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Campbell, Petya K. E.

    2007-01-01

    The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

  16. Total-reflection X-ray fluorescence studies of trace elements in biomedical samples

    Energy Technology Data Exchange (ETDEWEB)

    Kubala-Kukus, A. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland)]. E-mail: Aldona.Kubala-Kukus@pu.kielce.pl; Braziewicz, J. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland); Pajek, M. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland)

    2004-08-31

    Application of the total-reflection X-ray fluorescence (TXRF) analysis in the studies of trace element contents in biomedical samples is discussed in the following aspects: (i) a nature of trace element concentration distributions, (ii) censoring approach to the detection limits, and (iii) a comparison of two sets of censored data. The paper summarizes the recent results achieved in this topics, in particular, the lognormal, or more general logstable, nature of concentration distribution of trace elements, the random left-censoring and the Kaplan-Meier approach accounting for detection limits and, finally, the application of the logrank test to compare the censored concentrations measured for two groups. These new aspects, which are of importance for applications of the TXRF in different fields, are discussed here in the context of TXRF studies of trace element in various samples of medical interest.

  17. Metals determination in coffee sample by total reflection X-ray fluorescence analysis (TXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Brienza, Sandra Maria Boscolo [ Universidade Metodista de Piracicaba (UNIMEP), Piracicaba, SP (Brazil). Faculdade de Ciencias Matematicas, da Natureza e de Tecnologia da Informacao]. E-mail: sbrienza@unimep.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio Franco do [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: virgilio@cena.usp.br

    2005-07-01

    The objective of this study was to evaluate the inorganic concentration in five brands of coffee, three of them nationally marketed and the others of an exportation kind. The samples were prepared by infusion with deionized water. To carry out the calibration, standard solutions were prepared with different concentrations of Al, Si, K, Ca, Ti, Cr, Fe, Ni, Zn and Se. The measurements were carried out using a white beam of synchrotron radiation for excitation and a Si (Li) semiconductor detector for detection. By employing Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF) it was possible to evaluate the concentrations of P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Rb and Ba. The detection limits for 300 s counting time were in the range of 0.03 (Ca) to 30 ng.g{sup -1} (Rb), respectively. (author)

  18. Metals determination in coffee sample by total reflection X-ray fluorescence analysis (TXRF)

    International Nuclear Information System (INIS)

    Vives, Ana Elisa Sirito de

    2005-01-01

    The objective of this study was to evaluate the inorganic concentration in five brands of coffee, three of them nationally marketed and the others of an exportation kind. The samples were prepared by infusion with deionized water. To carry out the calibration, standard solutions were prepared with different concentrations of Al, Si, K, Ca, Ti, Cr, Fe, Ni, Zn and Se. The measurements were carried out using a white beam of synchrotron radiation for excitation and a Si (Li) semiconductor detector for detection. By employing Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF) it was possible to evaluate the concentrations of P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Rb and Ba. The detection limits for 300 s counting time were in the range of 0.03 (Ca) to 30 ng.g -1 (Rb), respectively. (author)

  19. Total and available metal contents in sediments by synchrotron radiation total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Sobrinho, Gilmar A. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil]. E-mail: silvana@fecf.unicamp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil); Jesus, Edgar F.O. de; Lopes, Ricardo T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    2002-07-01

    In this work the total and available contents of Al, Si, Cl, K, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Ba, Ce and Pb in sediments from river Atibaia were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence technique. The detection limits for K series varies from 200 ng.mL{sup -1} for Al to 2 ng.mL{sup -1} for Zn while for L series the value varies from 20 ng.mL{sup -1} for Ba to 10 ng.mL{sup -1} for Pb. The samples were submitted to two different processes, in order to obtain the total and biological available metal contents. The information about metal content is a important parameter for a correct evaluation about the hydrologic cycle in Piracicaba basin. All the measure were carried out at the National Synchrotron Light Laboratory, Campinas, SP, Brazil, using a white beam for excitation. (author)

  20. Impurities determination in uranium eluates by total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Bellavigna, Horacio J.; Eppis, Maria R.; Ramella, Jose L.

    1999-01-01

    The chemical control of impurities in nuclear materials is indispensable in order to assure an efficient operation of the reactors. The maximum concentration admitted depends of the elements and in most cases are in the parts per billion range. Conventional analytical methods require a pre-concentration treatment of the sample and a previous separation of the matrix (uranium). This paper investigates the use of the total reflection X-ray fluorescence as an alternative methodology for the determination of impurities in nuclear materials, namely K, Ca, Ti, Cr, Mn, Fe, Ni, Cu and As. The detection limits obtained were in the range of 0.1 to 20 ng/ml for a 1000 seconds counting time. (author)

  1. First Total Reflection X-Ray Fluorescence round-robin test of water samples: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Borgese, Laura; Bilo, Fabjola [Chemistry for Technologies Laboratory, University of Brescia, Brescia (Italy); Tsuji, Kouichi [Graduate School of Engineering, Osaka City University, Osaka (Japan); Fernández-Ruiz, Ramón [Servicio Interdepartamental de Investigación (SIdI), Laboratorio de TXRF, Universidad Autónoma de Madrid, Madrid (Spain); Margui, Eva [Department of Chemistry, University of Girona, Girona (Spain); Streli, Christina [TU Wien, Atominstitut,Radiation Physics, Vienna (Austria); Pepponi, Giancarlo [Fondazione Bruno Kessler, Povo, Trento (Italy); Stosnach, Hagen [Bruker Nano GmbH, Berlin (Germany); Yamada, Takashi [Rigaku Corporation, Takatsuki, Osaka (Japan); Vandenabeele, Peter [Department of Archaeology, Ghent University, Ghent (Belgium); Maina, David M.; Gatari, Michael [Institute of Nuclear Science and Technology, University of Nairobi, Nairobi (Kenya); Shepherd, Keith D.; Towett, Erick K. [World Agroforestry Centre (ICRAF), Nairobi (Kenya); Bennun, Leonardo [Laboratorio de Física Aplicada, Departamento de Física, Universidad de Concepción (Chile); Custo, Graciela; Vasquez, Cristina [Gerencia Química, Laboratorio B025, Centro Atómico Constituyentes, San Martín (Argentina); Depero, Laura E., E-mail: laura.depero@unibs.it [Chemistry for Technologies Laboratory, University of Brescia, Brescia (Italy)

    2014-11-01

    Total Reflection X-Ray Fluorescence (TXRF) is a mature technique to evaluate quantitatively the elemental composition of liquid samples deposited on clean and well polished reflectors. In this paper the results of the first worldwide TXRF round-robin test of water samples, involving 18 laboratories in 10 countries are presented and discussed. The test was performed within the framework of the VAMAS project, interlaboratory comparison of TXRF spectroscopy for environmental analysis, whose aim is to develop guidelines and a standard methodology for biological and environmental analysis by means of the TXRF analytical technique. - Highlights: • The discussion of the first worldwide TXRF round-robin test of water samples (18 laboratories of 10 countries) is reported. • Drinking, waste, and desalinated water samples were tested. • Data dispersion sources were identified: sample concentration, preparation, fitting procedure, and quantification. • The protocol for TXRF analysis of drinking water is proposed.

  2. Recent trends in total reflection X-ray fluorescence spectrometry for biological applications.

    Science.gov (United States)

    Szoboszlai, Norbert; Polgári, Zsófia; Mihucz, Victor G; Záray, Gyula

    2009-02-02

    This review is focused on the application of total reflection X-ray fluorescence (TXRF) spectrometry in the field of biological research. In the last decade, most papers were published by authors who applied laboratory-scale TXRF equipments. The application of synchrotron radiation as excitation source (SR-TXRF) shows a slowly increasing tendency. In the cited papers the micro-, trace and multielement capability of these TXRF techniques was demonstrated in the clinical and medical laboratory practice, as well as in various plant physiological studies. For speciation of elements in biological matrices, the TXRF was used as element specific detector following an off-line separation step (e.g., thin layer chromatography, high performance liquid chromatography), however, these off-line methods are not competitive with the on-line coupled HPLC-inductively coupled plasma mass spectrometry.

  3. Bromate determination in water after membrane complexation and total reflection X-ray fluorescence analysis.

    Science.gov (United States)

    Hatzistavros, Vasilios S; Koulouridakis, Pavlos E; Aretaki, Ioanna I; Kallithrakas-Kontos, Nikolaos G

    2007-04-01

    A new method for the determination of trace levels of bromates by selective membrane collection is presented. Various membranes containing a few micrograms of different complexing reagents in a poly(vinyl chloride) matrix were tested. These membranes were produced on the surface of quartz glass (reflectors), and they were immersed in solutions containing bromate and bromide ions. At the first stage the prepared membranes collected both bromate and bromide ions, so different bromide masking agents were put in the analyzed solutions to avoid bromide collection. By the end of the equilibration time, the reflectors were left to dry, and they were analyzed by total reflection X-ray fluorescence (TXRF). The poly(vinyl chloride) with aliquat-336 membrane and o-dianisidin complexing agent gave the best results. The minimum detection limit was equal to 0.9 ng/mL for ultrapure water and 1.0 ng/mL for drinking water.

  4. Multi-elemental analysis of produced water by synchrotron radiation total reflection X-ray fluorescence.

    Science.gov (United States)

    Pimentel, P M; Anjos, M J; Melo, D M A; Melo, M A F; Gonçalves, L M; Silva, C N; Lopes, R T

    2008-02-15

    The synchrotron radiation total reflection X-ray fluorescence (SRTXRF) technique was used for the analysis of heavy metals in produced water samples from oil field in Rio Grande do Norte, in order to determine potential sources of pollution. Since the inorganic components in produced water generally resembling sea water, pre-concentration procedures have been applied to increase the concentration of the analyte of interest and to minimize the salt matrix effects. This technique allows us to determine the contents of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Hg and Pb in 20 produced water samples. The great majority of the sampling points presented low elemental concentration value. However, in some sample, the Fe, Ni, Cu, Zn and Hg concentration were higher than the established limits by the Brazilian legislation.

  5. Characterization of hypoglycemiant plants by total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Zucchi, Orghêda L A D; Moreira, Silvana; de Jesus, Edgar F O; Neto, Helio Salvio; Salvador, Marcos J

    2005-03-01

    In this work, synchrotron radiation total reflection X-ray fluorescence spectrometry (SRTXRF) was used to determine trace elements in eight hypoglycemiant plants (Trigonella foenum graecum, Panax ginseng, Pfaffia paniculata, Myrcia speciosa, Zea mays, Harpagophytum procumbens, Syzygium jambolona, and Bauhinia forficate). The elements P, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, and Sr were detected in all medicinal plants investigated, whereas Si, S, Sc, V, Cr, Co, Ni, Se, Nb, Mo, Sn, Sb, Ba, Hg, and Pb were detected only in some of the samples. The concentration of elements in hypoglycemiant plants varied from 0.15 microg/g of Co to 3.0 x 10(4) microg/g of K and the mean of experimental limit of detection for these elements were 0.14 and 3.6 microg/g, respectively.

  6. An elemental correlation study in cancerous breast tissue by total reflection x-ray fluorescence.

    Science.gov (United States)

    Majewska, U; Braziewicz, J; Banaś, D; Kubala-Kukuś, A; Góźdź, S; Pajek, M; Smok, J; Urbaniak, A

    1997-01-01

    The total reflection x-ray fluorescence method (TRXRF) has been employed to determine of P, S, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Rb, Sr, and Pb concentration in the benign breast tumor tissue from 68 women and in the cancerous breast tissue from 26 women. Concentrations of most of elements show enhancement in cancerous breast tissue. Examined elements compete for binding sites in the cell, change its enzymatic activity, and exert direct or indirect action on the carcinogenic process accelerating the growth of tumors. Inhibition of enzymatic activity caused by variation in trace element concentrations results in immunological breakdown of the body system. An attempt has been made to correlate measured trace element concentrations with the clinical stage of cancer. Physical bases of used analytical method, experimental setup, and the procedure of sample preparation are described.

  7. Total reflection X-ray fluorescence polymer spectra: classification by taxonomy statistic tools.

    Science.gov (United States)

    Vázquez, Cristina; Boeykens, Susana; Bonadeo, H

    2002-07-19

    The aim of this work is to explore the use of chemometric tools for the classification of synthetic and natural polymers with a mean molecular weight greater than 10(6). Total Reflection X-Ray Fluorescence (TXRF) spectra were obtained and analyzed in order to retrieve matrix information and to illustrate the calibration procedure. The intensities of the coherent and incoherent scattered peaks were specially selected for this purpose. The polymers studied were aqueous solutions of scleroglucan, polyacrilamide, polyoxyethylene oxide, glucomannan, 2,3,6-tri-o-ethylamylose and xhantan, in concentrations upto 1% (m/m). matlab software was used for numerical calculations. Using a combination of principal component analysis and cluster analysis, the differences in composition of various analyzed polymers can be visualized.

  8. Complexing membrane for uranium detection by total reflection X-ray fluorescence.

    Science.gov (United States)

    Hatzistavros, Vasilios; Koulouridakis, Pavlos; Kallithrakas-Kontost, Nikolaos

    2005-07-01

    Selective membranes containing a few micrograms of various complexing reagents in a polyvinyl chloride (PVC) matrix were produced in order to determine low uranium concentrations in water. The membranes were produced on the surfaces of quartz glasses, and immersed in water solutions containing uranium salts (5 - 50 ng/mL). By the end of the equilibration time, the membranes were left to dry and analyzed based on the total reflection X-ray fluorescence. The effects of the complexing agents and their mass proportions added in the membranes were studied. The combination of the complexing reagents dithizone and thiourea gave the best result. The minimum detection limit was measured to be equal to 0.8 ng/mL.

  9. Selective mercury determination after membrane complexation and total reflection X-ray fluorescence analysis.

    Science.gov (United States)

    Koulouridakis, Pavlos E; Kallithrakas-Kontos, Nikolaos G

    2004-08-01

    A new method for low mercury concentration analysis in drinking waters is presented. Membranes containing a few micrograms of various complexing reagents were produced on the surface of quartz glasses (reflectors). The reflectors were immersed in water solutions containing various concentrations of inorganic mercury salts at low concentrations (1-40 ng/mL). The membranes were left to equilibrate in 5-500 mL of solution for many hours; when the equilibration stage was finished they were cleaned with ultrapure water and left to dry. Analyses were performed by total reflection X-ray fluorescence (TXRF). The effects of various experimental parameters (complexing agent, equilibrium time, sample volume, etc.) as well as the selectivity of the membranes were studied. The complexing reagent dithizone with a PVC-based membrane gave the best results. The limit of quantitation was 0.8 ng/mL.

  10. Determination of copper nanoparticle size distributions with total reflection X-ray fluorescence spectroscopy.

    Science.gov (United States)

    Singh, Andy; Luening, Katharina; Brennan, Sean; Homma, Takayuki; Kubo, Nobuhiro; Nowak, Stanisław H; Pianetta, Piero

    2017-01-01

    Total reflection X-ray fluorescence (TXRF) analysis is extensively used by the semiconductor industry for measuring trace metal contamination on silicon surfaces. In addition to determining the quantity of impurities on a surface, TXRF can reveal information about the vertical distribution of contaminants by measuring the fluorescence signal as a function of the angle of incidence. In this study, two samples were intentionally contaminated with copper in non-deoxygenated and deoxygenated ultrapure water (UPW) resulting in impurity profiles that were either atomically dispersed in a thin film or particle-like, respectively. The concentration profile of the samples immersed into deoxygenated UPW was calculated using a theoretical concentration profile representative of particles, yielding a mean particle height of 16.1 nm. However, the resulting theoretical profile suggested that a distribution of particle heights exists on the surface. The fit of the angular distribution data was further refined by minimizing the residual error of a least-squares fit employing a model with a Gaussian distribution of particle heights about the mean height. The presence of a height distribution was also confirmed with atomic force microscopy measurements.

  11. Multi-element analysis by portable total reflection X-ray fluorescence spectrometer.

    Science.gov (United States)

    Liu, Ying; Imashuku, Susumu; Kawai, Jun

    2013-01-01

    Multi-element solutions containing the 11 elements S, K, Sc, V, Mn, Co, Cu, Ga, As, Br and Y were analyzed by a portable total reflection X-ray fluorescence (TXRF) spectrometer. The excitation parameters (glancing angle, operational voltage and current) and sample amount were optimized for the portable TXRF in order to realize the smallest possible detection limits for all elements. The excitation parameter dependencies of the fluorescence signal and background for the detected elements are explained in detail. Background contributed by the sample carrier is also discussed. Consequently, nine elements were detectable at sub-nanogram levels in a single measurement of 10 min under the optimal experimental conditions. The portable TXRF spectrometer was found to be suitable for simultaneous multi-element analysis with low detection limits. The features of high sensitivity, small sample amount required, and fast detection of a wide range of elements make the portable TXRF a valuable tool in various applications, such as field studies in environmental and geological investigations.

  12. Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence

    Science.gov (United States)

    Leitão, R. G.; Palumbo, A.; Souza, P. A. V. R.; Pereira, G. R.; Canellas, C. G. L.; Anjos, M. J.; Nasciutti, L. E.; Lopes, R. T.

    2014-02-01

    Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann-Whitney U test it was observed that almost all elements presented concentrations with significant differences (α=0.05) between the groups studied.

  13. Elemental analysis within the electrical double layer using total reflection X-ray fluorescence technique.

    Science.gov (United States)

    Shapovalov, Vladimir L; Ryskin, Mikhail E; Konovalov, Oleg V; Hermelink, Antje; Brezesinski, Gerald

    2007-04-19

    A simplified total reflection X-ray fluorescence (TRXF) technique is proposed for the study of the electrical double layer (EDL) near charged monolayers at the air-water interface. In contrast to the parent NTEF (near total external reflection X-ray fluorescence) method, TRXF uses a fixed angle of incidence (below the critical one) and abandons both "spatial resolution" (which is poor anyway) and "absolute calibration" with the bulk reference. These modifications reduce both the duration of experiments and the complexity of the data treatment by 1-2 orders of magnitude and turn TRXF into a truly simple tool for elemental analysis within the EDL. A few TRXF experiments appear sufficient to disprove the model of simultaneous binding of alkali earth metal cations and inorganic anions to negatively charged phospholipid monolayers as proposed in literature. Direct experimental support was provided to the essential feature of the EDL near highly charged interfaces: The main amount of counterions is concentrated in the thin inner part of the EDL irrespective of the electrolyte concentration in the bulk. A study of the counterion competition for the participation in the EDL of highly negatively charged behenylsulfate (BS) monolayers (resulting from packing density limitations) revealed that univalent Cs+ is quite competitive with divalent Ca2+ and Ba2+ (which contradicts the classical Gouy-Chapman model). If the univalent/divalent ion ratio in bulk is 9:1, the corresponding ratio in the EDL is ca. 1.5 for Cs+/Ca2+ and 0.5 for Cs+/Ba2+, whereas the model predicts 0.14 only. Bearing in mind packing density limitations, these values are consistent with a series of sizes for hydrated ions: Cs+ < Ba2+ < Ca2+.

  14. Study of archaeological ceramics by total-reflection X-ray fluorescence spectrometry: Semi-quantitative approach

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Ruiz, R. [Universidad Autonoma de Madrid, Facultad de Ciencias, Servicio Interdepartamental de Investigacion, Modulo C-9, Laboratorio de TXRF, Crta. Colmenar, Km 15, Cantoblanco, E-28049, Madrid (Spain)], E-mail: ramon.fernandez@uam.es; Garcia-Heras, M. [Instituto de Historia-CSIC, C/Serrano, 13. E-28001, Madrid (Spain); CENIM-CSIC, Avda. Gregorio del Amo, 8. E-28040, Madrid (Spain)

    2007-10-15

    Total-reflection X-ray fluorescence spectrometry has been compared with Instrumental Neutron Activation Analysis in order to test its potential application to the study of archaeological ceramics in the archaeometric field. Two direct solid non-chemical sample preparation procedures have been checked: solid sedimentation and solid chemical homogenization. For sedimentation procedure, total-reflection X-ray fluorescence allows the analysis of the elemental composition with respect to the size fraction but not the average evaluation of the composition. For solid chemical homogenization procedure, total-reflection X-ray fluorescence provides precise (from 0.8% to 27% of coefficient of variation) and accurate results (from 91% to 110% of recovery) for 15 elements (Cr, Hf, Ni, Rb, Al, Ba, Ca, K, Mn, Ti, V, Cu, Ga, Y and Fe) with an easy sample preparation process of the solid clay and without previous chemical treatment. The influence of the particle sizes has been checked by total-reflection X-ray fluorescence sample angle scans and anomalous behaviors have been found for three additional detected elements: As, Sr and Zn, which can be attributed to interference effects of the mineral grain sizes of their associated chemical phases in the total-reflection X-ray fluorescence interference region. The solid chemical homogenization procedure produces data useful for archaeological interpretation, which is briefly illustrated by a case-study. Finally, the decantation procedure data can be also useful for size chemical speciation and, consequently, for alternative environmental total-reflection X-ray fluorescence applications.

  15. 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.

  16. Total Reflection X-ray Fluorescence attachment module modified for analysis in vacuum

    International Nuclear Information System (INIS)

    Wobrauschek, P.; Streli, C.; Kregsamer, P.; Meirer, F.; Jokubonis, C.; Markowicz, A.; Wegrzynek, D.; Chinea-Cano, E.

    2008-01-01

    Based on the design of the low cost Total Reflection X-Ray Fluorescence attachment module available since 1986 from Atominstitut (WOBRAUSCHEK-module) which can be attached to existing X-ray equipment, a new version was developed which allows the analysis of samples in vacuum. This design was in particular possible as the Peltier cooled light weight Silicon Drift Detector is following all adjustment procedures for total reflection as angle rotation and linear motion. The detector is mounted through a vacuum feed and O-ring tightening to the small vacuum chamber. The standard 30 mm round quartz, Si-wafer or Plexiglas reflectors are used to carry the samples. The reflectors are placed on the reference plane with the dried sample down looking facing in about 0.5 mm distance the up looking detector window. The reflectors are resting on 3 steel balls defining precisely the reference plane for the adjustment procedure. As the rotation axis of the module is in the plane of the reflector surface, angle dependent experiments can be made to distinguish between film and particulate type contamination of samples. Operating with a Mo anode at 50 kV and 40 mA with a closely attached multilayer monochromator and using a 10 mm 2 KETEK silicon drift detector with 8 μm Be window, a sensitivity of 70 cps/ng for Rb was measured and detection limits of 2 pg were obtained

  17. Combined fluorescence, reflectance, and ground measurements of a stressed Norway spruce forest for forest damage assessment

    Science.gov (United States)

    Banninger, C.

    1991-01-01

    The detection and monitoring of stress and damage in forested areas is of utmost importance to forest managers for planning purposes. Remote sensing are the most suitable means to obtain this information. This requires that remote sensing data employed in a forest survey be properly chosen and utilized for their ability to measure canopy spectral features directly related to key tree and canopy properties that are indicators of forest health and vitality. Plant reflectance in the visible to short wave IR regions (400 to 2500 nm) provides information on its biochemical, biophysical, and morphological make up, whereas plant fluorescence in the 400 to 750 nm region is more indicative of the capacity and functioning of its photosynthetic apparatus. A measure of both these spectral properties can be used to provide an accurate assessment of stress and damage within the forest canopy. Foliar chlorophyll and nitrogen are essential biochemical constituents required for the proper functioning and maintenance of a plant's biological processes. Chlorophyll-a is the prime reactive center for photosynthesis, by which a plant converts CO2 and H2O into necessary plant products. Nitrogen forms an important component of the amino-acids, enzymes, proteins, alkaloids, and cyanogenic compounds that make up a plant, including its pigments. Both chlorophyll and nitrogen have characteristic absorption features in the visible to short wave IR region. By measuring the wavelength position and depth of these features and the fluorescence response of the foliage, the health and vitality of a canopy can be ascertained. Examples for a stressed Norway spruce forest in south-eastern Austria are presented.

  18. Direct Analysis of Metal Ions in Solutions with High Salt Concentrations by Total Reflection X-ray Fluorescence.

    Science.gov (United States)

    Regadío, Mercedes; Riaño, Sofía; Binnemans, Koen; Vander Hoogerstraete, Tom

    2017-04-18

    Total reflection X-ray fluorescence (TXRF) is becoming more and more popular for elemental analysis in academia and industry. However, simplification of the procedures for analyzing samples with complex compositions and residual matrix effects is still needed. In this work, the effect of an inorganic (CaCl 2 ) and an organic (tetraalkylphosphonium chloride) matrix on metals quantification by TXRF was investigated for liquid samples. The samples were spiked with up to 20 metals at concentrations ranging from 3 to 50 mg L -1 per element, including elements with spectral peaks near the peaks of the matrix elements or near the Raleigh and Compton scattering peaks of the X-ray source (molybdenum anode). The recovery rate (RR) and the relative standard deviation (RSD) were calculated to express the accuracy and the precision of the measured element concentrations. In samples with no matrix effects, good RRs are obtained regardless of the internal standard selected. However, in samples with moderate matrix content, the use of an optimum internal standard (OIS) at a concentration close to that of the analyte significantly improved the quantitative analysis. In samples with high concentrations of inorganic ions, using a Triton X-100 aqueous solution to dilute the sample during the internal standardization resulted in better RRs and lower RSDs compared to using only water. In samples with a high concentration of organic material, pure ethanol gave slightly better results than when a Triton X-100-ethanol solution was used for dilution. Compared to previous methods reported in the literature, the new sample-preparation method gave better accuracy, precision, and sensitivity for the elements tested. Sample dilution with an OIS and the surfactant Triton X-100 (inorganic media) or ethanol (organic media) is recommended for fast routine elemental determination in matrix containing samples, as it does not require special equipment, experimentally derived case-dependent mathematical

  19. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  20. Development of off-line layer chromatographic and total reflection X-ray fluorescence spectrometric methods for arsenic speciation

    Energy Technology Data Exchange (ETDEWEB)

    Mihucz, Victor G. [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); Moricz, Agnes M. [L. Eoetvoes University, Department of Chemical Technology and Environmental Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Kroepfl, Krisztina [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Szikora, Szilvia [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Tatar, Eniko [Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Parra, Lue Meru Marco [Universidad Centro-occidental Lisandro Alvarado, Decanato de Agronomia, Departamento de Quimica y Suelos Unidad de Analisis Instrumental, Apartado Postal 4076, Cabudare 3023 (Venezuela); Zaray, Gyula [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary) and Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary) and L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary)]. E-mail: zaray@ludens.elte.hu

    2006-11-15

    Rapid and low cost off-line thin layer chromatography-total reflection X-ray fluorescence spectrometry and overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods have been developed for separation of 25 ng of each As(III), As(V), monomethyl arsonic acid and dimethylarsinic acid applying a PEI cellulose stationary phase on plastic sheets and a mixture of acetone/acetic acid/water = 2:1:1 (v/v/v) as eluent system. The type of eluent systems, the amounts (25-1000 ng) of As species applied to PEI cellulose plates, injection volume, development distance, and flow rate (in case of overpressured thin layer chromatography) were taken into consideration for the development of the chromatographic separation. Moreover, a microdigestion method employing nitric acid for the As spots containing PEI cellulose scratched from the developed plates divided into segments was developed for the subsequent total reflection X-ray fluorescence spectrometry analysis. The method was applied for analysis of root extracts of cucumber plants grown in As(III) containing modified Hoagland nutrient solution. Both As(III) and As(V) were detected by applying the proposed thin layer chromatography/overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods.

  1. Development of off-line layer chromatographic and total reflection X-ray fluorescence spectrometric methods for arsenic speciation

    Science.gov (United States)

    Mihucz, Victor G.; Móricz, Ágnes M.; Kröpfl, Krisztina; Szikora, Szilvia; Tatár, Enikő; Parra, Lué Merú Marcó; Záray, Gyula

    2006-11-01

    Rapid and low cost off-line thin layer chromatography-total reflection X-ray fluorescence spectrometry and overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods have been developed for separation of 25 ng of each As(III), As(V), monomethyl arsonic acid and dimethylarsinic acid applying a PEI cellulose stationary phase on plastic sheets and a mixture of acetone/acetic acid/water = 2:1:1 (v/v/v) as eluent system. The type of eluent systems, the amounts (25-1000 ng) of As species applied to PEI cellulose plates, injection volume, development distance, and flow rate (in case of overpressured thin layer chromatography) were taken into consideration for the development of the chromatographic separation. Moreover, a microdigestion method employing nitric acid for the As spots containing PEI cellulose scratched from the developed plates divided into segments was developed for the subsequent total reflection X-ray fluorescence spectrometry analysis. The method was applied for analysis of root extracts of cucumber plants grown in As(III) containing modified Hoagland nutrient solution. Both As(III) and As(V) were detected by applying the proposed thin layer chromatography/overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods.

  2. Distinguishing nitrogen fertilization levels in field corn (Zea mays L.) with actively induced fluorescence and passive reflectance measurements

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Meisinger, J.J.; Corp, L.A

    1994-01-01

    Laser-induced fluorescence (LIF) is an active sensing technique capable of capturing immediate and specific indications of changes in plant physiology and metabolism as they relate to the concentration and photosynthetic activity of the plant pigments. Reflectance is a passive sensing technique that can capture differences in the concentration of the primary plant pigments. Fluorescence and reflectance were compared for their ability to measure levels of plant stress that are of agronomic importance in corn (Zea mays L.) crops. Laboratory LIF and reflectance spectra were made on excised leaves from field grown corn. Changes in the visible region of the spectrum were compared between groups of plants fertilized with seven different levels of nitrogen (N) fertilization. A pulsed nitrogen laser emitting photons at a wavelength of 337 nm was used as a fluorescence excitation source. Differences in maximum intensity of fluorescence occurred at 440 nm, 525 nm, 685 nm, and 740 nm. Significant separations were found between levels of N fertilization at several LIF wavelength ratios. Several reflectance algorithms also produced significant separations between certain levels of N fertilization

  3. Response of grapevine leaves to plasmopara viticola infection by means of measurement of reflectance and fluorescence signals

    Czech Academy of Sciences Publication Activity Database

    Šebela, David; Olejníčková, Julie; Župčanová, A.; Sotolář, R.

    2012-01-01

    Roč. 27, č. 8 (2012), s. 229-237 ISSN 1211-8516 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Plasmopara viticola * downy mildew * grapevine * leaf tissue * susceptible varieties * chlorophyll fluorescence imaging * reflectance Subject RIV: GM - Food Processing

  4. Generally Applicable Transformation Protocols for Fluorescent Nanodiamond Internalization into Cells.

    Science.gov (United States)

    Hemelaar, Simon R; van der Laan, Kiran J; Hinterding, Sophie R; Koot, Manon V; Ellermann, Else; Perona-Martinez, Felipe P; Roig, David; Hommelet, Severin; Novarina, Daniele; Takahashi, Hiroki; Chang, Michael; Schirhagl, Romana

    2017-07-19

    Fluorescent nanodiamonds (FNDs) are promising nanoprobes, owing to their stable and magnetosensitive fluorescence. Therefore they can probe properties as magnetic resonances, pressure, temperature or strain. The unprecedented sensitivity of diamond defects can detect the faint magnetic resonance of a single electron or even a few nuclear spins. However, these sensitivities are only achieved if the diamond probe is close to the molecules that need to be detected. In order to utilize its full potential for biological applications, the diamond particle has to enter the cell. Some model systems, like HeLa cells, readily ingest particles. However, most cells do not show this behavior. In this article we show for the first time generally applicable methods, which are able to transport fluorescent nanodiamonds into cells with a thick cell wall. Yeast cells, in particular Saccharomyces cerevisiae, are a favored model organism to study intracellular processes including aging on a cellular level. In order to introduce FNDs in these cells, we evaluated electrical transformation and conditions of chemical permeabilization for uptake efficiency and viability. 5% DMSO (dimethyl sulfoxide) in combination with optimized chemical transformation mix leads to high uptake efficiency in combination with low impact on cell biology. We have evaluated all steps in the procedure.

  5. Determination of arsenic in water samples by Total Reflection X-Ray Fluorescence using pre-concentration with alumina

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Haydn [Laboratorio de Fisica Nuclear, Dpto. De Fisica, Universidad Simon Bolivar, Sartenejas, Baruta (Venezuela, Bolivarian Republic of); Marco Parra, Lue-Meru, E-mail: luemerumarco@yahoo.e [Universidad Centroccidental Lisandro Alvarado, Dpto. Quimica y Suelos, Decanato de Agronomia, Tarabana, Cabudare, Edo.Lara (Venezuela, Bolivarian Republic of); Bennun, Leonardo [Universidad de Concepcion, Concepcion (Chile); Greaves, Eduardo D. [Laboratorio de Fisica Nuclear, Dpto. De Fisica, Universidad Simon Bolivar, Sartenejas, Baruta (Venezuela, Bolivarian Republic of)

    2010-06-15

    The determination of arsenic in water samples requires techniques of high sensitivity. Total Reflection X-Ray Fluorescence (TXRF) allows the determination but a prior separation and pre-concentration procedure is necessary. Alumina is a suitable substrate for the selective separation of the analytes. A method for separation and pre-concentration in alumina, followed by direct analysis of the alumina is evaluated. Quantification was performed using the Al-K{alpha} and Co-K{alpha} lines as internal standard in samples prepared on an alumina matrix, and compared to a calibration with aqueous standards. Artificial water samples of As (III) and As (V) were analyzed after the treatment. Fifty milliliters of the sample at ppb concentration levels were mixed with 10 mg of alumina. The pH, time and temperature were controlled. The alumina was separated from the slurry by centrifugation, washed with de-ionized water and analyzed directly on the sample holder. A pre-concentration factor of 100 was found, with detection limit of 0.7 {mu}gL{sup -1}. The percentage of recovery was 98% for As (III) and 95% for As (V) demonstrating the suitability of the procedure.

  6. Total reflection X-ray fluorescence as a convenient tool for determination of trace elements in microscale gasoline and diesel

    Science.gov (United States)

    Zhang, Airui; Jin, Axiang; Wang, Hai; Wang, Xiaokang; Zha, Pengfei; Wang, Meiling; Song, Xiaoping; Gao, Sitian

    2018-03-01

    Quantitative determination of trace elements like S, Fe, Cu, Mn and Pb in gasoline and S in diesel is of great importance due to the growing concerns over air pollution, human health and engine failure caused by utilization of gasoline and diesel with these harmful elements. A method of total reflection X-ray fluorescence (TXRF) was developed to measure these harmful trace elements in gasoline and diesel. A variety of factors to affect measurement results, including TXRF parameters, microwave-assisted digestion conditions and internal standard element and its addition, were examined to optimize these experimental procedures. The hydrophobic treatment of the surface of quartz reflectors to support the analyte with neutral silicone solutions could prepare thin films of gasoline and diesel digestion solutions for subsequent TXRF analysis. The proposed method shows good potential and reliability to determine the content of harmful trace elements in gasoline and diesel with high sensitivity and accuracy without drawing different standard calibration curves, and can be easily employed to screen gasoline and diesel in routine quality control and assurance.

  7. Multi-element analysis of vegetal foodstuff by means of low power total reflection X-ray fluorescence (TXRF) spectrometry.

    Science.gov (United States)

    Dalipi, Rogerta; Marguí, Eva; Borgese, Laura; Depero, Laura E

    2017-03-01

    In this work, an analytical methodology in combination with a low power benchtop total reflection X-ray fluorescence (TXRF) system has been developed for multi-elemental analysis of vegetal materials. An easy and rapid sample preparation consisting in suspending 20mg of sample in de-ionized water showed to be the most suitable for this kind of samples. However, for comparison purposes, two digestion procedures were also applied. A set of fifteen certified reference materials and three real vegetal samples were employed for the quantitative determination of K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Pb, As and Sn. All the parameters affecting sample preparation and TXRF measurements conditions were carefully evaluated. Accurate and precise results were obtained for mid-high Z elements (Mn-Sr) using internal standardization as quantification approach, while for light Z elements (K and Ca), due to absorption effects, an improvement of analytical results by external calibration was necessary. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. A novel total reflection X-ray fluorescence procedure for the direct determination of trace elements in petrochemical products

    Energy Technology Data Exchange (ETDEWEB)

    Cinosi, Amedeo [Sasol Italy SpA, Paderno Dugnano (Italy); GNR srl, Agrate Conturbia, Novara (Italy); Andriollo, Nunzio [Sasol Italy SpA, Paderno Dugnano (Italy); Pepponi, Giancarlo [Fondazione Bruno Kessler, Povo, Trento (Italy); Monticelli, Damiano [Universita degli Studi dell' Insubria - sede di Como, Dipartimento di Scienze Chimiche e Ambientali, Como, CO (Italy)

    2011-01-15

    A total reflection X-ray fluorescence (TXRF) procedure was developed for the determination of metal traces in petrochemical end products or intermediates for surfactant synthesis. The method combines a fast and straightforward sample preparation, i.e. deposition on the sample holder and evaporation of the sample matrix, with an efficient quantification method based on internal standardization (organic gallium standard). The method developed showed detection limits below 0.05 {mu}g g{sup -1} and in most cases below 0.005 {mu}g g{sup -1}. Fifteen elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Rh, Sn, Sr, V and Zn) were determined in matrices such as paraffins, n-olefins, linear alkylbenzenes, long-chain alkyl alcohols and esters: typical metal contents were below 1 {mu}g g{sup -1}. The results were compared with the reference method ASTM D5708 (test method B) based on inductively coupled plasma optical emission spectroscopy: advantages and drawbacks of the two procedures were critically evaluated. The TXRF method developed showed comparable precision and absence of bias with respect to the reference method. A comparison of the performances of the two methods is presented. (orig.)

  9. Simultaneous multielement determination in vegetable foodstuffs and their respective cell fractions by total-reflection X-ray fluorescence (TXRF).

    Science.gov (United States)

    Günther, K; von Bohlen, A

    1990-04-01

    Total-reflection X-ray fluorescence (TXRF) was employed in the multielement determination made on samples of lamb's lettuce and cauliflower as well as in the analysis of their soluble and insoluble cell fractions. All samples were digested with HNO3 and the elements were quantitatively determined with Ga as internal standard. For cell fractionation, the freeze-dried vegetables were mortared in the presence of fine-grain quartz and extracted with a buffer solution; the resulting suspension was then separated by ultracentrifugation into cytosol and pellet components. K, Ca, Mn, Fe, Cu, Zn, Rb and Sr were the elements of which the total content and distribution between cytosol and pellet were determined. As a result of the cellular digestion and extraction procedures employed, greater than or equal to 50% of the total metal contents of Zn, Cu, K and Rb could be reduced to the cytosol phase in both vegetables, however, Sr, Fe, Ca and Mn were mainly bound to the insoluble pellet components which, in the case of cauliflower, contained up to 100% of the total Sr content. As a multielement method, TXRF proved to be an excellent analytical tool in these investigations, since it requires only minute samples with simple preparation and involves a large dynamic measuring scale.

  10. A novel total reflection X-ray fluorescence procedure for the direct determination of trace elements in petrochemical products.

    Science.gov (United States)

    Cinosi, Amedeo; Andriollo, Nunzio; Pepponi, Giancarlo; Monticelli, Damiano

    2011-01-01

    A total reflection X-ray fluorescence (TXRF) procedure was developed for the determination of metal traces in petrochemical end products or intermediates for surfactant synthesis. The method combines a fast and straightforward sample preparation, i.e. deposition on the sample holder and evaporation of the sample matrix, with an efficient quantification method based on internal standardization (organic gallium standard). The method developed showed detection limits below 0.05 μg g(-1) and in most cases below 0.005 μg g(-1). Fifteen elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Rh, Sn, Sr, V and Zn) were determined in matrices such as paraffins, n-olefins, linear alkylbenzenes, long-chain alkyl alcohols and esters: typical metal contents were below 1 μg g(-1). The results were compared with the reference method ASTM D5708 (test method B) based on inductively coupled plasma optical emission spectroscopy: advantages and drawbacks of the two procedures were critically evaluated. The TXRF method developed showed comparable precision and absence of bias with respect to the reference method. A comparison of the performances of the two methods is presented.

  11. Trace elemental analysis of commercial bottled drinking water by a portable total reflection X-ray fluorescence spectrometer.

    Science.gov (United States)

    Kunimura, Shinsuke; Kawai, Jun

    2007-10-01

    A portable total reflection X-ray fluorescence spectrometer was applied to commercial bottled drinking water containing 62 ppb (microg/L) V, 7.5 ppm (mg/L) Ca, and 1 ppm K. A dry residue, prepared by repeated pipetting and drying a 20 microL portion of drinking water on a sample holder six times, and another dry residue, prepared by pipetting and drying a 120 microL portion of the drinking water, were measured. The size of the dry residue of the drinking water was reduced by repeating the pipetting and drying. Calcium and potassium were easily detected in these two dry residues. Vanadium was detected in the dry residue prepared by repeated pipetting and drying. Vanadium, calcium, and potassium were quantified by using an internal standard, and the average quantified concentrations of V, Ca, and K were 91 ppb, 8.2 ppm, and 1.5 ppm, respectively. Although these quantified concentrations deviated from the certified concentrations (62 ppb of V, 7.5 ppm of Ca, and 1 ppm of K), it was possible for this portable spectrometer to estimate approximate concentrations.

  12. 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)

  13. Investigation of the internal reflectance and prediction of infrared diffuse reflectance of the polymeric coating on aluminum substrate

    Science.gov (United States)

    Ho, Wen-Dar; Ma, Chen-Chi M.

    1998-02-01

    This study employs the ray tracing method to develop and analyze mathematical formulae for the IR diffuse reflectance of the polymeric coating on a metal substrate. The effects of the thickness and the absorption property of the polymer film on the internal reflectance are also investigated. In addition, the diffuse reflectance of the coating/substrate system which is irradiated with a perfect diffuse source is formulated as well. Analysis results indicate that the internal reflectance of the internal front surface (polymer/air interface) is not a constant which depends on the film thickness and absorption property. Closely examining the internal multiple reflections between the front and the substrate surface reveals that the diffuse reflectance of the coating/substrate system can be obtained by summing the fractions of rays emerging from the front surface. By knowing the refractive index and the extinction coefficient of the polymer, the diffuse reflectance of the coating/substrate system can be calculated by the formulae presented here. In addition an alkyd resin coating/aluminum substrate system is also implemented to compare the experimental reflectances with the calculated ones. According to the comparisons the analysis and developed formulae are quite effective.

  14. Investigation of polyelectrolytes by total reflection x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Varga, I.; Nagy, M.

    2000-01-01

    Water soluble polyelectrolyte samples containing mono-, bi- and trivalent metal ions were investigated without any pretreatment. Acid digestion of linear polymers may lead to a product insoluble in water so the digestion has to be avoided. The aim of this paper was the determination of analytical characteristics and limitations of the total reflection x-ray fluorescence (TXRF) analysis for poly (vinylalcohol-vinylsulphate) salts and poly (acrylic acid, acrylamide) copolymers containing the following cations: K + , Cs + , Ba 2+ , Cu 2+ and La 3+ . On the basis of our results efficiency of ion-exchange during preparation of polyelectrolytes and stoichiometry of the end-product were determined. TXRF results were compared with data gained by inductively coupled plasma atomic emission spectrometry (ICP-AES) measurements except in the case of Cs + which has poor sensitivity in ICP-AES. Good agreement was found between the results of the two techniques and calculations from titrimetric data. Concentration of Li + and Mg 2+ in polymer samples was measured by ICP-AES. In majority of cases film-like dry residues of aqueous solutions of polyelectrolytes can be characterized by homogeneous spatial distribution of metal ions within the organic matrix. This is because the migration of the ions is hindered during drying process. Determination of metals in polyelectrolyte films by TXRF is quite ideal as model for analysis of plant, animal or human tissues which is a frequent task in environmental and inorganic biomedical analytical chemistry. (author)

  15. Synchrotron radiation total reflection x-ray fluorescence analysis; of polymer coated silicon wafers

    International Nuclear Information System (INIS)

    Brehm, L.; Kregsamer, P.; Pianetta, P.

    2000-01-01

    It is well known that total reflection x-ray fluorescence (TXRF) provides an efficient method for analyzing trace metal contamination on silicon wafer surfaces. New polymeric materials used as interlayer dielectrics in microprocessors are applied to the surface of silicon wafers by a spin-coating process. Analysis of these polymer coated wafers present a new challenge for TXRF analysis. Polymer solutions are typically analyzed for bulk metal contamination prior to application on the wafer using inductively coupled plasma mass spectrometry (ICP-MS). Questions have arisen about how to relate results of surface contamination analysis (TXRF) of a polymer coated wafer to bulk trace analysis (ICP-MS) of the polymer solutions. Experiments were done to explore this issue using synchrotron radiation (SR) TXRF. Polymer solutions were spiked with several different concentrations of metals. These solutions were applied to silicon wafers using the normal spin-coating process. The polymer coated wafers were then measured using the SR-TXRF instrument set-up at the Stanford Synchrotron Radiation Laboratory (SSRL). Several methods of quantitation were evaluated. The best results were obtained by developing calibration curves (intensity versus ppb) using the spiked polymer coated wafers as standards. Conversion of SR-TXRF surface analysis results (atoms/cm 2 ) to a volume related concentration was also investigated. (author)

  16. Characterization and classification of spirituous beverages by total reflection x-ray fluorescence

    International Nuclear Information System (INIS)

    Davila, E.G. de; Lue-Meru, M.P.; Capote, T.; Greaves, E.

    2000-01-01

    The total reflection x-ray fluorescence (TXRF) technique was applied for the multi-elemental analysis of spirituous beverages like rum, cocuy (typical spirituous beverage in Venezuela), whiskey and wine, in order to classify the samples by product processing and geographical origin by chemometric analysis. Special attention was paid to the cocuy samples, since there is a lack of quality control of this beverage, mainly due to the home-made product processing. The use of the Compton peak information was evaluated for the determination of organic content in samples. In the specifically case of cocuy samples the Compton peak area was correlated to the ash content for detection of adulteration with sugar syrup. Cocuy samples were also analyzed using gas chromatography, for pH, acidity, ash content and refractometry, in order to develop the recognition pattern. The TXRF analysis was carried out in a Canberra spectrometer, using the K α-line of a Motube, by a direct procedure previously developed. The analysis of the data was done by using principal components analysis and a confidence test. The results show that TXRF and chemometric analysis is a useful tool for quality control of spirituous beverages, not only concerning to metal content, but also in the evaluation of sugar and non volatile organic content. (author)

  17. Total reflection X-ray fluorescence as a tool for food screening

    Science.gov (United States)

    Borgese, Laura; Bilo, Fabjola; Dalipi, Rogerta; Bontempi, Elza; Depero, Laura E.

    2015-11-01

    This review provides a comprehensive overview of the applications of total reflection X-ray fluorescence (TXRF) in the field of food analysis. Elemental composition of food is of great importance, since food is the main source of essential, major and trace elements for animals and humans. Some potentially toxic elements, dangerous for human health may contaminate food, entering the food chain from the environment, processing, and storage. For this reason the elemental analysis of food is fundamental for safety assessment. Fast and sensitive analytical techniques, able to detect major and trace elements, are required as a result of the increasing demand on multi-elemental information and product screening. TXRF is suitable for elemental analysis of food, since it provides simultaneous multi-elemental identification in a wide dynamic range of concentrations. Several different matrices may be analyzed obtaining results with a good precision and accuracy. In this review, the most recent literature about the use of TXRF for the analysis of food is reported. The focus is placed on the applications within food quality monitoring of drinks, beverages, vegetables, fruits, cereals, animal derivatives and dietary supplements. Furthermore, this paper provides a critical outlook on the developments required to transfer these methods from research to the industrial and analytical laboratories contexts.

  18. Sample pretreatment strategies for total reflection X-ray fluorescence analysis: A tutorial review

    Energy Technology Data Exchange (ETDEWEB)

    De La Calle, I.; Cabaleiro, N.; Romero, V.; Lavilla, I.; Bendicho, C., E-mail: bendicho@uvigo.es

    2013-12-01

    In the last years, there has been a revival of total reflection X-ray fluorescence spectrometry (TXRF), which was firstly applied for analytical purposes in the late 80s. The aim of this work is to discuss and compare the current approaches for sample pretreatment including in situ microdigestion, slurry preparation, acid digestion, extraction, etc. prior to TXRF analysis. Advantages and drawbacks inherent to each of those procedures are considered. A comprehensive revision in the period January 2008–July 2013 about different sample preparation strategies prior to TXRF analysis apart from early pioneering reports dealing with sample pretreatment are included in the review. Non-conventional sample pretreatment approaches such as microflow online preconcentration, lab-on-a-chip, etc., are also discussed. Finally, future prospects in sample preparation prior to TXRF analysis are outlined. - Highlights: • We review sample pretreatment for TXRF in a comprehensive way. • Strategies for analysis of solid, liquid and gaseous samples are discussed. • A tutorial review is presented covering the period January 2008–July 2013. • Future prospects for sample pretreament approaches in TXRF are outlined.

  19. Determination of element levels in human serum: Total reflection X-ray fluorescence applications

    Science.gov (United States)

    Majewska, U.; Łyżwa, P.; Łyżwa, K.; Banaś, D.; Kubala-Kukuś, A.; Wudarczyk-Moćko, J.; Stabrawa, I.; Braziewicz, J.; Pajek, M.; Antczak, G.; Borkowska, B.; Góźdź, S.

    2016-08-01

    Deficiency or excess of elements could disrupt proper functioning of the human body and could lead to several disorders. Determination of their concentrations in different biological human fluids and tissues should become a routine practice in medical treatment. Therefore the knowledge about appropriate element concentrations in human organism is required. The purpose of this study was to determine the concentration of several elements (P, S, Cl, K, Ca, Cr, Fe, Cu, Zn, Se, Br, Rb, Pb) in human serum and to define the reference values of element concentration. Samples of serum were obtained from 105 normal presumably healthy volunteers (66 women aged between 15 and 78 years old; 39 men aged between 15 and 77 years old). Analysis has been done for the whole studied population and for subgroups by sex and age. It is probably first so a wide study of elemental composition of serum performed in the case of Świętokrzyskie region. Total reflection X-ray fluorescence (TXRF) method was used to perform the elemental analysis. Spectrometer S2 Picofox (Bruker AXS Microanalysis GmbH) was used to identify and measure elemental composition of serum samples. Finally, 1st and 3rd quartiles were accepted as minimum and maximum values of concentration reference range.

  20. Total reflection X-ray fluorescence (TXRF) for direct analysis of aerosol particle samples.

    Science.gov (United States)

    Bontempi, E; Zacco, A; Benedetti, D; Borgese, L; Colombi, P; Stosnach, H; Finzi, G; Apostoli, P; Buttini, P; Depero, L E

    2010-04-14

    Atmospheric aerosol particles have a great impact on the environment and on human health. Routine analysis of the particles usually involves only the mass determination. However, chemical composition and phases provide fundamental information about the particles' origins and can help to prevent health risks. For example, these particles may contain heavy metals such as Pb, Ni and Cd, which can adversely affect human health. In this work, filter samples were collected in Brescia, an industrial town located in Northern Italy. In order to identify the chemical composition and the phases of the atmospheric aerosols, the samples were analysed by means of total reflection X-ray fluorescence (TXRF) spectrometry with a laboratory instrument and X-ray microdiffraction at Synchrotron Daresbury Laboratories, Warrington (Cheshire, UK). The results are discussed and correlated to identify possible pollution sources. The novelty of this analytical approach is that filter samples for TXRF were analysed directly and did not require chemical pretreatment to leach elements from the aerosol particulates. The results of this study clearly show that TXRF is a powerful technique for the analysis of atmospheric aerosols on 'as-received' filters, thereby leaving samples intact and unaltered for possible subsequent analyses by other methods. In addition, the low detection limits for many elements (low ng/cm2) indicate that this method may hold promise in various application fields, such as nanotechnology.

  1. Improvement of total reflection X-ray fluorescence spectrometer sensitivity by flowing nitrogen gas

    Science.gov (United States)

    Imashuku, Susumu; Tee, Deh Ping; Kawai, Jun

    2012-07-01

    The intensity of Ar Kα line was reduced by a factor of 17 times by flowing more than 400 mL min- 1 of N2 gas through gas pipe placed at the gap between the X-ray detector and the sample stage of the total reflection X-ray fluorescence (TXRF) spectrometer. The signal-to-background ratios of characteristic X-rays with energies less than 8 keV were improved by flowing N2 gas owing to the reduction of peak pileups related to the Ar Kα peak. The improvement of the signal-to-background ratios became significant as the energies of the characteristic X-rays approached that of the Ar Kα line (2.96 keV) for characteristic X-rays with energies less than 5 keV. When 1 μL of solution containing 10 mg L- 1 cadmium (10 ng) was measured with the TXRF spectrometer by flowing N2 gas, Cd Lα line was clearly observed, although the Cd Lα line overlapped with the Ar K lines without flowing N2 gas. The lower limit of detection of cadmium evaluated from the Cd Lα line was improved from 7.0 to 2.2 ng by flowing N2 gas. This N2 gas flowing technique can be applied to trace element analysis of cadmium in solutions which do not contain potassium such as leaching solutions from products containing cadmium in TXRF and conventional XRF measurements.

  2. Determination of halide impurities in ionic liquids by total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Vander Hoogerstraete, Tom; Jamar, Steven; Wellens, Sil; Binnemans, Koen

    2014-04-15

    The determination and quantification of halide impurities in ionic liquids is highly important because halide ions can significantly influence the chemical and physical properties of ionic liquids. The use of impure ionic liquids in fundamental studies on solvent extraction or catalytic reactions can lead to incorrect experimental data. The detection of halide ions in solution by total reflection X-ray fluorescence (TXRF) has been problematic because volatile hydrogen halide (HX) compounds are formed when the sample is mixed with the acidic metal standard solution. The loss of HX during the drying step of the sample preparation procedure gives imprecise and inaccurate results. A new method based on an alkaline copper standard Cu(NH3)4(NO3)2 is presented for the determination of chloride, bromide, and iodide impurities in ionic liquids. The 1-butyl-3-methylimidazolium ([C4mim]) ionic liquids with the anions acetate ([C4mim][OAc]), nitrate ([C4mim][NO3]), trifluoromethanesulfonate ([C4mim][OTf]), and bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]) were synthesized via a halide-free route and contaminated on purpose with known amounts of [C4mim]Cl, [C4mim]Br, [C4mim]I, or potassium halide salts in order to validate the new method and standard.

  3. Negligible water surface charge determined using Kelvin probe and total reflection X-ray fluorescence techniques.

    Science.gov (United States)

    Shapovalov, Vladimir L; Möhwald, Helmuth; Konovalov, Oleg V; Knecht, Volker

    2013-09-07

    The water surface charge has been extensively debated in recent decades. Electrophoretic mobilities of air bubbles in water and disjoining pressures between the surfaces of aqueous films suggest that the surface of water exhibits a significant negative charge. This is commonly attributed to a strong adsorption of hydroxide ions at the interface, though spectroscopic measurements and simulation studies suggest surface depletion of hydroxide ions. Alternatively, the negative surface charge could arise from surface contamination with trace charged surfactants. We have probed the variation in the surface charge of water with pH by measuring surface potentials using the Kelvin probe technique. Independently, the abundance in the interfacial layer of "reporter ions" (Rb(+) and Br(-)), which must be affected by a charged surface, has been monitored using the total reflection X-ray fluorescence (TRXF) technique. Special care was taken to prove the high sensitivity of this technique as well as to avoid surface contaminants. The magnitude of the surface charge was found to be below 1 e per 500 nm(2) (TRXF). No evidence of variations in the surface potential between pH 2-3 and pH 9-12 was detected within the accuracies of the methods (5 mV for Kelvin probe and 2 mV for TRXF). Hence, our findings suggest that the clean water surface exhibits negligible charge in a wide pH range.

  4. Chemical analysis of used three-way catalysts by total reflection X-ray fluorescence.

    Science.gov (United States)

    Fernández-Ruiz, R; Furió, M; Galisteo, F Cabello; Larese, C; López Granados, M; Mariscal, R; Fierro, J L G

    2002-11-01

    The methodology developed for evaluating, by total reflection X-ray fluorescence, the main elements in used three-way catalysts for cars after more than 59 000 km is described. The analytical method does not require chemical manipulation of the samples, is quick (30 min for sample preparation and 10 min for analysis), precise (between 1% and 10% of variation coefficient), and simple. The two catalytic monoliths contained in the cartridge of a car with more than 59,000 km have been analyzed. The mass relationships between the detected elements and Si, a component of the cordierite ceramic substrate, have been used to follow the axial and radial profiles of the elements. Information concerning the loss of active elements and the retention of contaminating elements as a consequence of the working conditions was attained by comparison between the results obtained for the used catalyst (59 000 km) with those of a fresh catalyst (0 km). The interface effect between the first and the second catalytic bricks was also studied.

  5. Development of an in situ polarization-dependent total-reflection fluorescence XAFS measurement system.

    Science.gov (United States)

    Chun, W J; Tanizawa, Y; Shido, T; Iwasawa, Y; Nomura, M; Asakura, K

    2001-03-01

    An in situ polarization-dependent total-reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) spectroscopy system has been developed, which enables PTRF-XAFS experiments to be performed in three different orientations at various temperatures (273-600 K) and pressures (10(-10) approximately 760 torr). The system consists of a measurement chamber and a preparation chamber. The measurement chamber has a high-precision six-axis goniometer and a multielement solid-state detector. Using a transfer chamber, also operated under ultra-high-vacuum conditions, the sample can be transferred to the measurement chamber from the preparation chamber, which possesses low-energy electron diffraction, Auger electron spectroscopy and X-ray photoelectron spectroscopy facilities, as well as a sputtering gun and an annealing system. The in situ PTRF-EXAFS for Cu species on TiO2 (110) has been measured in three different orientations, revealing anisotropic growth of Cu under the influence of the TiO2 (110) surface.

  6. Value of Online Group Reflection After International Service-Learning Experiences: I Never Thought of That.

    Science.gov (United States)

    Smit, Eileen M; Tremethick, Mary Jane

    Reflection is a widely accepted learning tool and a component of competent professional practice. An exploratory descriptive study was conducted to compare the breadth and level of reflection between students engaged in individual reflection papers and students engaged in an online group reflection discussion after an international cultural immersion service-learning program. Results indicated that students participating in the online group discussion had a higher level of reflective thinking and discussed more topics in their written reflections.

  7. 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

  8. A portable total reflection X-ray fluorescence spectrometer with a diamond-like carbon coated X-ray reflector.

    Science.gov (United States)

    Kunimura, Shinsuke; Ohmori, Hitoshi

    2012-01-21

    A diamond-like carbon (DLC) coated quartz glass sample holder is used in a portable total reflection X-ray fluorescence (TXRF) spectrometer. A spot area of a water sample on the DLC sample holder becomes smaller than that on a quartz glass sample holder usually used in TXRF analysis because DLC is more hydrophobic. Therefore, the use of the DLC sample holder enhances fluorescent X-rays reaching a detector compared with the use of a quartz glass sample holder, leading to improvement in detection sensitivity. A detection limit of 28 pg is achieved for Cr in a river water sample when using the DLC sample holder.

  9. Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

    Science.gov (United States)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2010-06-01

    Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ( α = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 μg g - 1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of "Citrus Leaves" and a blank were treated in the same way.

  10. Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2010-01-01

    Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2 O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different (α = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 μg g -1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of 'Citrus Leaves' and a blank were treated in the same way.

  11. Censoring: a new approach for detection limits in total-reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Pajek, M. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland)]. E-mail: pajek@pu.kielce.pl; Kubala-Kukus, A. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland); Braziewicz, J. [Institute of Physics, Swietokrzyska Academy, Swietokrzyska 15, 25-406 Kielce (Poland)

    2004-08-31

    It is shown that the detection limits in the total-reflection X-ray fluorescence (TXRF), which restrict quantification of very low concentrations of trace elements in the samples, can be accounted for using the statistical concept of censoring. We demonstrate that the incomplete TXRF measurements containing the so-called 'nondetects', i.e. the non-measured concentrations falling below the detection limits and represented by the estimated detection limit values, can be viewed as the left random-censored data, which can be further analyzed using the Kaplan-Meier (KM) method correcting for nondetects. Within this approach, which uses the Kaplan-Meier product-limit estimator to obtain the cumulative distribution function corrected for the nondetects, the mean value and median of the detection limit censored concentrations can be estimated in a non-parametric way. The Monte Carlo simulations performed show that the Kaplan-Meier approach yields highly accurate estimates for the mean and median concentrations, being within a few percent with respect to the simulated, uncensored data. This means that the uncertainties of KM estimated mean value and median are limited in fact only by the number of studied samples and not by the applied correction procedure for nondetects itself. On the other hand, it is observed that, in case when the concentration of a given element is not measured in all the samples, simple approaches to estimate a mean concentration value from the data yield erroneous, systematically biased results. The discussed random-left censoring approach was applied to analyze the TXRF detection-limit-censored concentration measurements of trace elements in biomedical samples. We emphasize that the Kaplan-Meier approach allows one to estimate the mean concentrations being substantially below the mean level of detection limits. Consequently, this approach gives a new access to lower the effective detection limits for TXRF method, which is of prime interest

  12. Fluorescent H{sub 2} Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

    Energy Technology Data Exchange (ETDEWEB)

    Le, Huynh Anh N.; Pak, Soojong; Lee, Hye-In [School of Space Research, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104 (Korea, Republic of); Kaplan, Kyle; Mace, Gregory; Pavel, Michael; Jaffe, Daniel T. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Lee, Sungho; Jeong, Ueejeong; Chun, Moo-Young; Yuk, In-Soo; Hwang, Narae; Kim, Kang-Min; Park, Chan; Oh, Jae Sok; Yu, Young Sam; Park, Byeong-Gon; Minh, Young Chol [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Oh, Heeyoung [Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Pyo, Tae-Soo, E-mail: huynhanh7@khu.ac.kr, E-mail: soojong@khu.ac.kr [Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS), 650 North Aohoku Place, Hilo, HI 96720 (United States)

    2017-05-20

    We have analyzed the temperature, velocity, and density of H{sub 2} gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph, we detected 68 H{sub 2} emission lines within the 1″ × 15″ slit. The diagnostic ratio of 2-1 S(1)/1-0 S(1) is 0.41−0.56. In addition, the estimated ortho-to-para ratio (OPR) is 1.63−1.82, indicating that the H{sub 2} emission transitions in the observed region arise mostly from gas excited by UV fluorescence. Gradients in the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H{sub 2} from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly formed H{sub 2} should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1″ × 1″ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ∼10{sup 5} cm{sup −3} with a size smaller than ∼5 × 10{sup −3} pc embedded in lower-density regions of 10{sup 3}–10{sup 4} cm{sup −3}.

  13. Total reflection of x-ray fluorescence (TXRF): a mature technique for environmental chemical nanoscale metrology

    Science.gov (United States)

    Borgese, L.; Zacco, A.; Bontempi, E.; Colombi, P.; Bertuzzi, R.; Ferretti, E.; Tenini, S.; Depero, L. E.

    2009-08-01

    Total reflection x-ray fluorescence (TXRF) is a technique well established for chemical analysis of samples deposited as a thin layer. Nowadays it is mainly employed for electronic industry quality control. Recently, very compact and economic TXRF instrumentation was proposed. Combining this with the capability to analyze liquid samples, this technique is suitable to be employed in many different applications, comprising the very critical field of environmental analysis. Comparisons with the standard atomic absorption spectroscopy (AAS) technique show that TXRF is a practical, accurate, and reliable technique. Indeed, round-robin activities have already been started. Despite the efficiency and economy of the developed portable TXRF instrumentation, this is not widely employed for chemical laboratory analysis probably because TXRF is not an officially recognized technique, i.e. it is not yet normative-subjected. This fact could also be due to the long background of analytical applications developed for AAS, ICPS or inductively coupled plasma mass spectroscopy (ICP-MS) up to now. In this paper, we present a work of environmental monitoring of an industrial site, performed by means of bioindicators (lichens). The analysis of trace elements concentration in lichen was usually conducted with spectrophotometric techniques, such as AAS and ICP-MS, which were accepted by common regulations and normative-subjected. In this study, we accomplished a comparative lichen analysis by AAS and TXRF. The reproducibility of the obtained results showed the high correspondence between the two techniques. This comparison highlighted the versatility of the TXRF apparatus that allowed more rapid and simultaneous element detection. The obtained results suggested that this portable TXRF system could be suitable for regulation to produce certificated analysis upto ppb concentrations for some elements.

  14. Fluorescent H_2 Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

    International Nuclear Information System (INIS)

    Le, Huynh Anh N.; Pak, Soojong; Lee, Hye-In; Kaplan, Kyle; Mace, Gregory; Pavel, Michael; Jaffe, Daniel T.; Lee, Sungho; Jeong, Ueejeong; Chun, Moo-Young; Yuk, In-Soo; Hwang, Narae; Kim, Kang-Min; Park, Chan; Oh, Jae Sok; Yu, Young Sam; Park, Byeong-Gon; Minh, Young Chol; Oh, Heeyoung; Pyo, Tae-Soo

    2017-01-01

    We have analyzed the temperature, velocity, and density of H_2 gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph, we detected 68 H_2 emission lines within the 1″ × 15″ slit. The diagnostic ratio of 2-1 S(1)/1-0 S(1) is 0.41−0.56. In addition, the estimated ortho-to-para ratio (OPR) is 1.63−1.82, indicating that the H_2 emission transitions in the observed region arise mostly from gas excited by UV fluorescence. Gradients in the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H_2 from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly formed H_2 should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1″ × 1″ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ∼10"5 cm"−"3 with a size smaller than ∼5 × 10"−"3 pc embedded in lower-density regions of 10"3–10"4 cm"−"3.

  15. Total reflection X-ray fluorescence analysis of airborne silver nanoparticles from fabrics.

    Science.gov (United States)

    Menzel, Magnus; Fittschen, Ursula Elisabeth Adriane

    2014-03-18

    Ag nanoparticles (NPs) are usually applied to consumer products because of their antimicrobial properties, which are desired in fabrics for sportswear as well as cloth used for cleaning. Hazards to human health from airborne Ag NPs may occur when the NPs are inhaled. NPs are comparable in size to macromolecules and viruses and able to penetrate deep into the lungs, e.g., the alveoli, where they may cause damage to cells and tissue due to their large surface area. In this study, aerosols released form fabrics treated with Ag NPs were collected using a low pressure Berner impactor and analyzed with total reflection X-ray fluorescence (TXRF). We found that the Ag NPs are released primarily in the form of larger particles, mainly 0.13-2 μm, probably attached to fiber material. Using an electron micro probe, single particles could be identified. The detection of backscattered electrons suggests small spots on the particle consist of a heavier element, which most likely is Ag, although the signal in energy-dispersive X-ray spectroscopy (EDX) was below the lower limit of detection (LOD). To achieve LODs necessary for Ag determination, Ar peaks were eliminated by a nitrogen atmosphere provided by the "Picofox-box". This enables linear calibration and quantification of Ag. The LOD was calculated at 0.2 ng (2.0 ppb). Following the TXRF and scanning electron microscopy (SEM)/EDX analysis, the aerosol samples were dissolved in nitric acid and analyzed with ICPMS to successfully confirm the results obtained by the TXRF measurements.

  16. Pigment particles analysis with a total reflection X-ray fluorescence spectrometer: study of influence of instrumental parameters

    Energy Technology Data Exchange (ETDEWEB)

    Coccato, Alessia; Vandenabeele, Peter [Ghent University, Department of Archaeology, Ghent (Belgium); Vekemans, Bart; Vincze, Laszlo; Moens, Luc [Ghent University, Department of Analytical Chemistry, Ghent (Belgium)

    2016-12-15

    Total reflection X-ray fluorescence (TXRF) analysis is an excellent tool to determine major, minor and trace elements in minuscule amounts of samples, making this technique very suitable for pigment analysis. Collecting minuscule amounts of pigment material from precious works of art by means of a cotton swab is a well-accepted sampling method, but poses specific challenges when TXRF is to be used for the characterization of the unknown material. (orig.)

  17. Pigment particles analysis with a total reflection X-ray fluorescence spectrometer: study of influence of instrumental parameters

    Science.gov (United States)

    Coccato, Alessia; Vekemans, Bart; Vincze, Laszlo; Moens, Luc; Vandenabeele, Peter

    2016-12-01

    Total reflection X-ray fluorescence (TXRF) analysis is an excellent tool to determine major, minor and trace elements in minuscule amounts of samples, making this technique very suitable for pigment analysis. Collecting minuscule amounts of pigment material from precious works of art by means of a cotton swab is a well-accepted sampling method, but poses specific challenges when TXRF is to be used for the characterization of the unknown material.

  18. Polychromatic excitation improves detection limits in total reflection X-ray fluorescence analysis compared with monochromatic excitation.

    Science.gov (United States)

    Kunimura, Shinsuke; Kawai, Jun

    2010-08-01

    Detection limits obtained by a portable total reflection X-ray fluorescence (TXRF) spectrometer with or without a monochromator are compared. A 1 W X-ray tube (tube voltage: 20 kV) is used in this spectrometer. Polychromatic excitation improves the detection limits in TXRF analysis with the low power X-ray tube compared with monochromatic excitation. A detection limit of 26 pg is achieved for Co when using the weak polychromatic X-rays.

  19. Chlorophyll Fluorescence and Reflectance-Based Non-Invasive Quantification of Blast, Bacterial Blight and Drought Stresses in Rice

    Czech Academy of Sciences Publication Activity Database

    Šebela, David; Quiňones, C.; Cruz, C.; Ona, I.; Olejníčková, Julie; Jagadish, K. S. V.

    2018-01-01

    Roč. 59, č. 1 (2018), s. 30-43 ISSN 0032-0781 R&D Projects: GA MŠk(CZ) LO1415 EU Projects: European Commission(XE) 284443 - EPPN Institutional support: RVO:86652079 Keywords : marker-assisted selection * oryza-sativa l. * water- stress * magnaporthe-grisea * disease resistance * photosynthetic efficiency * spectral reflectance * carotenoid content * eucalyptus leaves * diurnal changes * Bacterial blight * Chlorophyll fluorescence * Drought stress * Reflectance * Rice bast Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 4.760, year: 2016

  20. Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, T., E-mail: tmc@servidor.unam.m [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Lartigue, J. [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico, D.F. 04510 (Mexico); Zarazua, G.; Avila-Perez, P. [National Institute of Nuclear Research. Ocoyoacac, Edo. de Mexico, 05045 (Mexico); Navarrete, M. [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico, D.F. 04510 (Mexico); Tejeda, S. [National Institute of Nuclear Research. Ocoyoacac, Edo. de Mexico, 05045 (Mexico)

    2010-06-15

    Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO{sub 3} and H{sub 2}O{sub 2} (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ({alpha} = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 {mu}g g{sup -1}. A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of 'Citrus Leaves' and a blank were treated in the same way.

  1. Total reflection X-ray fluorescence analysis of oral fluids of women affected by osteoporosis and osteopenia

    International Nuclear Information System (INIS)

    Sanchez, Hector Jorge; Valentinuzzi, Maria Cecilia; Grenon, Miram; Abraham, Jose

    2008-01-01

    Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures; the early stage of decreased bone density is called osteopenia. More than 200 million people are affected and about 50% of post-menopausic women are expected to develop the disease. Osteoporosis, osteopenia and periodontal disease have in common several risk factors, being hyperthyroidism and smoking habits the most important ones. There is scarce information in the literature about the association between periodontal disease and osteoporosis and/or osteopenia. Some works suggest that osteoporotic women are susceptible to a higher loss of periodontal insertion, alveolar bones, and teeth. Thirty adult post-menopausic women were studied; some of them were healthy (control group) and the rest of them were undergoing some stage of osteoporosis or osteopenia. All the subjects were healthy, non-smokers, not having dental implants, and with communitarian periodontal index higher than 1(CPI > 1). Samples of saliva and gingival crevice fluid were extracted with calibrated micro-capillaries and deposited on Si reflectors. Known amounts of Ga were added to the samples in order to act as internal standard for quantification by the total reflection x-ray fluorescence technique. Experimental concentrations of several elements (P, S, Cl, K, Ca, Cr, Fe, NI, Cu, and Zn) were determined. The concentration of some elements in saliva showed different behavior as compared to gingival crevice fluid. Some critical elements of bone composition, such as Ca and Zn, present very distinguishable behavior. Improvements in the statistics are required for a better assessment of a routine method and to establish some correlation with periodontal disease. TXRF seems to be a promising method to evaluate the evolution of osteoporosis

  2. Total reflection X-ray fluorescence analysis of oral fluids of women affected by osteoporosis and osteopenia

    Science.gov (United States)

    Sánchez, Héctor Jorge; Valentinuzzi, María Cecilia; Grenón, Miram; Abraham, José

    2008-12-01

    Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures; the early stage of decreased bone density is called osteopenia. More than 200 million people are affected and about 50% of post-menopausic women are expected to develop the disease. Osteoporosis, osteopenia and periodontal disease have in common several risk factors, being hyperthyroidism and smoking habits the most important ones. There is scarce information in the literature about the association between periodontal disease and osteoporosis and/or osteopenia. Some works suggest that osteoporotic women are susceptible to a higher loss of periodontal insertion, alveolar bones, and teeth. Thirty adult post-menopausic women were studied; some of them were healthy (control group) and the rest of them were undergoing some stage of osteoporosis or osteopenia. All the subjects were healthy, non-smokers, not having dental implants, and with communitarian periodontal index higher than 1(CPI > 1). Samples of saliva and gingival crevice fluid were extracted with calibrated micro-capillaries and deposited on Si reflectors. Known amounts of Ga were added to the samples in order to act as internal standard for quantification by the total reflection x-ray fluorescence technique. Experimental concentrations of several elements (P, S, Cl, K, Ca, Cr, Fe, NI, Cu, and Zn) were determined. The concentration of some elements in saliva showed different behavior as compared to gingival crevice fluid. Some critical elements of bone composition, such as Ca and Zn, present very distinguishable behavior. Improvements in the statistics are required for a better assessment of a routine method and to establish some correlation with periodontal disease. TXRF seems to be a promising method to evaluate the evolution of osteoporosis.

  3. Zinc and cadmium accumulation in single zebrafish ( Danio rerio) embryos — A total reflection X-ray fluorescence spectrometry application

    Science.gov (United States)

    Mages, Margarete; Bandow, Nicole; Küster, Eberhard; Brack, Werner; von Tümpling, Wolf

    2008-12-01

    Trace metals such as Cadmium (Cd) and Zinc (Zn) are known to exhibit adverse effects on many aquatic organisms including early life stages of fish. In contact with contaminated sediment, fish eggs and embryos may be exposed to metals via the water phase as well as via direct contact with contaminated particles. This may result in body burdens that are difficult to predict and may vary according to individual micro scale exposure conditions. The highly sensitive total reflection X-ray fluorescence spectrometry (TXRF) may provide a tool to analyse individual embryos for internal contaminant concentrations and thus helps to develop a better understanding of dose-response relationships. To test this hypothesis, embryos of Danio rerio were exposed to Cd and Zn spiked sediment in different treatments applying an ion exchange resin for modification of bioavailable concentrations. The TXRF analysis indicated individual embryos with dramatically enhanced exposure compared to other individuals despite uniform exposure conditions on a macro scale. Ion exchanger reduced embryo Zn concentrations to values close to control value with a comparably low standard deviation. Cadmium concentrations in embryos were in the range of 4000 to 7000 µg/g with a median of 5740 µg/g. A commercial ion exchanger reduced individual body burdens by a factor 50 to 100. Individual peak body burdens of up to 3160 µg/g were accompanied by reduced weight of the fish eggs due to early death i.e. coagulation. The investigation of exposure and effects on an individual-based scale may significantly help to reduce uncertainty and inconsistencies occurring in conventional analysis of pooled fish embryo samples.

  4. Zinc and cadmium accumulation in single zebrafish (Danio rerio) embryos - A total reflection X-ray fluorescence spectrometry application

    Energy Technology Data Exchange (ETDEWEB)

    Mages, Margarete [UFZ - Helmholtz Centre for Environmental Research, Dept. River Ecology Brueckstr. 3a/39114 Magdeburg/Germany (Germany); University of Lueneburg, Institute of Ecology and Environmental Chemistry, Department Environmental Chemistry, Scharnhorststrasse 1/21335 Lueneburg/Germany (Germany)], E-mail: margarete.mages@ufz.de; Bandow, Nicole [UFZ - Helmholtz Centre for Environmental Research, Dept. Effect Directed Analysis, Permoser Strasse 15/ 04318 Leipzig/Germany (Germany); Kuester, Eberhard [UFZ - Helmholtz Centre for Environmental Research, Dept. Bioanalytical Ecotoxicology, Permoser Strasse 15/ 04318 Leipzig/Germany (Germany); Brack, Werner [UFZ - Helmholtz Centre for Environmental Research, Dept. Effect Directed Analysis, Permoser Strasse 15/ 04318 Leipzig/Germany (Germany); Tuempling, Wolf von [UFZ - Helmholtz Centre for Environmental Research, Dept. River Ecology Brueckstr. 3a/39114 Magdeburg/Germany (Germany)

    2008-12-15

    Trace metals such as Cadmium (Cd) and Zinc (Zn) are known to exhibit adverse effects on many aquatic organisms including early life stages of fish. In contact with contaminated sediment, fish eggs and embryos may be exposed to metals via the water phase as well as via direct contact with contaminated particles. This may result in body burdens that are difficult to predict and may vary according to individual micro scale exposure conditions. The highly sensitive total reflection X-ray fluorescence spectrometry (TXRF) may provide a tool to analyse individual embryos for internal contaminant concentrations and thus helps to develop a better understanding of dose-response relationships. To test this hypothesis, embryos of Danio rerio were exposed to Cd and Zn spiked sediment in different treatments applying an ion exchange resin for modification of bioavailable concentrations. The TXRF analysis indicated individual embryos with dramatically enhanced exposure compared to other individuals despite uniform exposure conditions on a macro scale. Ion exchanger reduced embryo Zn concentrations to values close to control value with a comparably low standard deviation. Cadmium concentrations in embryos were in the range of 4000 to 7000 {mu}g/g with a median of 5740 {mu}g/g. A commercial ion exchanger reduced individual body burdens by a factor 50 to 100. Individual peak body burdens of up to 3160 {mu}g/g were accompanied by reduced weight of the fish eggs due to early death i.e. coagulation. The investigation of exposure and effects on an individual-based scale may significantly help to reduce uncertainty and inconsistencies occurring in conventional analysis of pooled fish embryo samples.

  5. Total reflection X-ray fluorescence analysis of oral fluids of women affected by osteoporosis and osteopenia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Hector Jorge [Facultad de Matematica Astronomia y Fisica, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)], E-mail: jsan@famaf.unc.edu.ar; Valentinuzzi, Maria Cecilia [Facultad de Matematica Astronomia y Fisica, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina); Grenon, Miram [Facultad de Odontologia, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina); Abraham, Jose [Facultad de Matematica Astronomia y Fisica, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)

    2008-12-15

    Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures; the early stage of decreased bone density is called osteopenia. More than 200 million people are affected and about 50% of post-menopausic women are expected to develop the disease. Osteoporosis, osteopenia and periodontal disease have in common several risk factors, being hyperthyroidism and smoking habits the most important ones. There is scarce information in the literature about the association between periodontal disease and osteoporosis and/or osteopenia. Some works suggest that osteoporotic women are susceptible to a higher loss of periodontal insertion, alveolar bones, and teeth. Thirty adult post-menopausic women were studied; some of them were healthy (control group) and the rest of them were undergoing some stage of osteoporosis or osteopenia. All the subjects were healthy, non-smokers, not having dental implants, and with communitarian periodontal index higher than 1(CPI > 1). Samples of saliva and gingival crevice fluid were extracted with calibrated micro-capillaries and deposited on Si reflectors. Known amounts of Ga were added to the samples in order to act as internal standard for quantification by the total reflection x-ray fluorescence technique. Experimental concentrations of several elements (P, S, Cl, K, Ca, Cr, Fe, NI, Cu, and Zn) were determined. The concentration of some elements in saliva showed different behavior as compared to gingival crevice fluid. Some critical elements of bone composition, such as Ca and Zn, present very distinguishable behavior. Improvements in the statistics are required for a better assessment of a routine method and to establish some correlation with periodontal disease. TXRF seems to be a promising method to evaluate the evolution of osteoporosis.

  6. Vapor phase treatment–total reflection X-ray fluorescence for trace elemental analysis of silicon wafer surface

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Hikari, E-mail: hikari@rigaku.co.jp [Rigaku Corp., 14-8 Akaoji-cho, Takatsuki, Osaka 569-1146 (Japan); Mori, Yoshihiro [Horiba Ltd., 2 Miyanohigashi, Kisshoin, Minami-ku, Kyoto 601-8510 (Japan); Shibata, Harumi [SUMCO Corporation, Seavance North, 1-2-1 Shibaura, Minato-ku, Tokyo 105-8634 (Japan); Shimazaki, Ayako [Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Shabani, Mohammad B. [Mitsubishi Material Corporation, 1-297, Kitabukuro-cho, Omiya-ku, Saitama 330-8508 (Japan); Yamagami, Motoyuki [Rigaku Corp., 14-8 Akaoji-cho, Takatsuki, Osaka 569-1146 (Japan); Yabumoto, Norikuni [Analysis Atelier Co., 4-36-4, Yoyogi, Shibuya-ku, Tokyo 151-0053 (Japan); Nishihagi, Kazuo [Horiba Ltd., 2 Miyanohigashi, Kisshoin, Minami-ku, Kyoto 601-8510 (Japan); Gohshi, Yohichi [Tsukuba University, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan)

    2013-12-01

    Vapor phase treatment (VPT) was under investigation by the International Organization for Standardization/Technical Committee 201/Working Group 2 (ISO/TC201/WG2) to improve the detection limit of total reflection X-ray fluorescence spectroscopy (TXRF) for trace metal analysis of silicon wafers. Round robin test results have confirmed that TXRF intensity increased by VPT for intentional contamination with 5 × 10{sup 9} and 5 × 10{sup 10} atoms/cm{sup 2} Fe and Ni. The magnification of intensity enhancement varied greatly (1.2–4.7 in VPT factor) among the participating laboratories, though reproducible results could be obtained for average of mapping measurement. SEM observation results showed that various features, sizes, and surface densities of particles formed on the wafer after VPT. The particle morphology seems to have some impact on the VPT efficiency. High resolution SEM observation revealed that a certain number of dots with SiO{sub 2}, silicate and/or carbon gathered to form a particle and heavy metals, Ni and Fe in this study were segregated on it. The amount and shape of the residue should be important to control VPT factor. - Highlights: • This paper presents a summary of study results of VPT–TXRF using ISO/TC201/WG2. • Our goal is to analyze the trace metallic contamination on silicon wafer with concentrations below 1 × 10{sup 10} atoms/cm{sup 2}. • The efficiency and mechanism of VPT are discussed under several round robin tests and systematic studies.

  7. Synchrotron radiation based micro X-ray fluorescence analysis of the calibration samples used in surface sensitive total reflection and grazing emission X-ray fluorescence techniques

    Science.gov (United States)

    Kubala-Kukuś, A.; Banaś, D.; Pajek, M.; Szlachetko, J.; Jagodziński, P.; Susini, J.; Salomé, M.

    2013-12-01

    Total reflection X-ray fluorescence (TXRF) and grazing emission X-ray fluorescence (GEXRF) are surface sensitive techniques and can be used for detailed surface studies of different materials, including ultra-low concentration contamination or the lateral and depth distributions of elements. The calibration procedure typically used involves placing a micro-droplet (˜μl) of the standard solution onto a silicon wafer (or quartz backing). After evaporation of the solvent, the residual amount of elements is used as a reference standard. Knowledge of the distribution of residue material on the substrate surface is crucial for precise quantification. In the present work the investigation of the lateral distribution of elements in the multielemental calibrating samples, containing the 23 most commonly studied elements, by using the synchrotron radiation based micro X-ray fluorescence is presented. The goal of this project was the study of a uniformity of the elemental distributions and determination of the residual elements morphology depending on the temperature of the drying process. The X-ray images were compared with optical and SEM images. Paper presents in details the experimental setup, sample preparation procedures, measurements and results. In the analysis of the X-ray images of the sample dried in high temperature the censoring approach was applied improving the quality of statistical analysis. The information on the elements distribution in the calibrating samples can be useful for developing more accurate calibration procedures applied in quantitative analysis of surface sensitive TXRF and GEXRF techniques.

  8. Characterization of urban air pollution by total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Schmeling, Martina

    2004-01-01

    Besides photochemical smog, particulate air pollution is a constantly growing problem in urban areas. The particulate matter present in pollution events contains often toxic or health impacting elements and is responsible for low visibility, might be triggering respiratory diseases like asthma, and can play an important role in formation or duration of smog events. To characterize particulate pollution in two different cities, samples were taken during intensive field campaigns in Chicago, IL, in 2002 and Phoenix, AZ, in 2001. Both cities experience regularly photochemical smog events as well as particulate pollution, but show very different meteorological and topographical conditions. Therefore it is expected that the particulate composition varies significantly, providing information about different pollution forms. Sampling took place in both cases at elevated locations and had a temporal resolution of 1.5 h and 1 h, respectively. The samples were analyzed by total reflection X-ray fluorescence after digestion of the filter matrix. As expected the elemental composition of particulate matter varied between both cities substantially with Phoenix showing a higher abundance of crustal elements, and Chicago enrichment in anthropogenically produced ones. In both cities diurnal patterns were found, exerting maxima in the morning and minima in the early afternoon. The diurnal pattern was much more regularly and also more strongly pronounced in Phoenix. Phoenix's valley location permits for a more stable nocturnal boundary layer to build up during the night thus trapping particulates efficiently during this time, until mixing occurs in the early morning hours and the residual layer lifts. In Chicago, the diurnal variation was less extreme, but another pattern determines the situation with the lake breeze. The lake breeze corresponds to a shift in wind direction towards the east, i.e. from Lake Michigan during the late morning. It was found that certain elemental species

  9. Total reflection x-ray fluorescence spectrometers for multielemental analysis: status of commercial equipment

    International Nuclear Information System (INIS)

    Ayala Jimenez, R.E.

    2000-01-01

    Multi-elemental analysis by total reflection x-ray fluorescence spectrometry has evolved during two decades. At the present there are commercial equipment available for the chemical analysis in all kind of biological and mineral samples. The electronic industry has also been benefited from the scientific and technological developments in the field of TXRF. The basic components of the spectrometers can be summarized as follow: a) excitation source; b) geometric arrangement (optics) for collimation and monochromatization of the primary radiation; c) x-ray detector; d) hardware and software for operation of the instrument, data acquisition and spectral deconvolution to determine the concentrations of the element present in the sample (quantitative analysis). As optional there are manufacturers offering the conventional 45 degrees geometry for direct excitation of bulky liquid or solid samples. Personal communications of the author and the commercial brochures available at the moment of writing this presentation have allowed to list the following type of components used in the TXRF spectrometers for multi-elemental analysis (the devices used in the electronic industry to analyze silicon wafers are excluded). Excitation: high power x-ray tube, output from 1300 to 2000 watts; metal ceramic low power-ray tube, output up to 50 watts. Different anodes are used but molybdenum, tungsten and copper are frequent. The excitation systems can be customized according to the requirements of the laboratory. Detector: Si-Li semi-conductor liquid nitrogen cooled; silicon solid state thermoelectrically cooled (silicon drift detector SDD and Si-PIN diode). Optics: multilayer monochromator of Si-W or Ni-C; double multilayer monochromator. Electronics: spectroscopy amplifier, analog to digital converter adapted to a PC compatible computer with software in Windows environment for the whole operation of the spectrometer and for qualy/quantitative analysis of samples are standards in the

  10. Improvement of total reflection X-ray fluorescence spectrometer sensitivity by flowing nitrogen gas

    Energy Technology Data Exchange (ETDEWEB)

    Imashuku, Susumu, E-mail: imashuku.susumu.2m@kyoto-u.ac.jp; Tee, Deh Ping; Kawai, Jun

    2012-07-15

    The intensity of Ar K{alpha} line was reduced by a factor of 17 times by flowing more than 400 mL min{sup -1} of N{sub 2} gas through gas pipe placed at the gap between the X-ray detector and the sample stage of the total reflection X-ray fluorescence (TXRF) spectrometer. The signal-to-background ratios of characteristic X-rays with energies less than 8 keV were improved by flowing N{sub 2} gas owing to the reduction of peak pileups related to the Ar K{alpha} peak. The improvement of the signal-to-background ratios became significant as the energies of the characteristic X-rays approached that of the Ar K{alpha} line (2.96 keV) for characteristic X-rays with energies less than 5 keV. When 1 {mu}L of solution containing 10 mg L{sup -1} cadmium (10 ng) was measured with the TXRF spectrometer by flowing N{sub 2} gas, Cd L{alpha} line was clearly observed, although the Cd L{alpha} line overlapped with the Ar K lines without flowing N{sub 2} gas. The lower limit of detection of cadmium evaluated from the Cd L{alpha} line was improved from 7.0 to 2.2 ng by flowing N{sub 2} gas. This N{sub 2} gas flowing technique can be applied to trace element analysis of cadmium in solutions which do not contain potassium such as leaching solutions from products containing cadmium in TXRF and conventional XRF measurements. - Highlights: Black-Right-Pointing-Pointer Intensity of Ar K{alpha} line was decreased by a factor of 17 times by flowing N{sub 2} gas. Black-Right-Pointing-Pointer S/N of characteristic X-rays with energies less than 8 keV were improved. Black-Right-Pointing-Pointer Detection limit of cadmium calculated from Cd L{alpha} line was improved from 7.0 to 2.2 ng by flowing N{sub 2} gas. Black-Right-Pointing-Pointer This technique can be applied to trace element analysis of Cd in leaching solutions.

  11. Homogeneous plate based antibody internalization assay using pH sensor fluorescent dye.

    Science.gov (United States)

    Nath, Nidhi; Godat, Becky; Zimprich, Chad; Dwight, Stephen J; Corona, Cesear; McDougall, Mark; Urh, Marjeta

    2016-04-01

    Receptor-mediated antibody internalization is a key mechanism underlying several anti-cancer antibody therapeutics. Delivering highly toxic drugs to cancer cells, as in the case of antibody drug conjugates (ADCs), efficient removal of surface receptors from cancer cells and changing the pharmacokinetics profile of the antibody drugs are some of key ways that internalization impacts the therapeutic efficacy of the antibodies. Over the years, several techniques have been used to study antibody internalization including radiolabels, fluorescent microscopy, flow cytometry and cellular toxicity assays. While these methods allow analysis of internalization, they have limitations including a multistep process and limited throughput and are generally endpoint assays. Here, we present a new homogeneous method that enables time and concentration dependent measurements of antibody internalization. The method uses a new hydrophilic and bright pH sensor dye (pHAb dye), which is not fluorescent at neutral pH but becomes highly fluorescent at acidic pH. For receptor mediated antibody internalization studies, antibodies against receptors are conjugated with the pHAb dye and incubated with the cells expressing the receptors. Upon binding to the receptor, the dyes conjugated to the antibody are not fluorescent because of the neutral pH of the media, but upon internalization and trafficking into endosomal and lysosomal vesicles the pH drops and dyes become fluorescent. The enabling attributes of the pHAb dyes are the hydrophilic nature to minimize antibody aggregation and bright fluorescence at acidic pH which allows development of simple plate based assays using a fluorescent reader. Using two different therapeutic antibodies--Trastuzumab (anti-HER2) and Cetuximab (anti-EGFR)--we show labeling with pHAb dye using amine and thiol chemistries and impact of chemistry and dye to antibody ration on internalization. We finally present two new approaches using the pHAb dye, which will be

  12. An Arduino-Based Experiment Designed to Clarify the Transition to Total Internal Reflection

    Science.gov (United States)

    Atkin, Keith

    2018-01-01

    The topic of refraction and reflection of light at the boundary of transparent media is a fundamentally important one. The special case of total internal reflection is however commonly misrepresented in elementary textbooks. This paper addresses the problem and describes an experimental procedure for measuring and displaying reflected and…

  13. An Arduino-based experiment designed to clarify the transition to total internal reflection

    Science.gov (United States)

    Atkin, Keith

    2018-03-01

    The topic of refraction and reflection of light at the boundary of transparent media is a fundamentally important one. The special case of total internal reflection is however commonly misrepresented in elementary textbooks. This paper addresses the problem and describes an experimental procedure for measuring and displaying reflected and transmitted light intensities using readily available components and the Arduino microcontroller.

  14. Extending Whole Slide Imaging: Color Darkfield Internal Reflection Illumination (DIRI for Biological Applications.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Kawano

    Full Text Available Whole slide imaging (WSI is a useful tool for multi-modal imaging, and in our work, we have often combined WSI with darkfield microscopy. However, traditional darkfield microscopy cannot use a single condenser to support high- and low-numerical-aperture objectives, which limits the modality of WSI. To overcome this limitation, we previously developed a darkfield internal reflection illumination (DIRI microscope using white light-emitting diodes (LEDs. Although the developed DIRI is useful for biological applications, substantial problems remain to be resolved. In this study, we propose a novel illumination technique called color DIRI. The use of three-color LEDs dramatically improves the capability of the system, such that color DIRI (1 enables optimization of the illumination color; (2 can be combined with an oil objective lens; (3 can produce fluorescence excitation illumination; (4 can adjust the wavelength of light to avoid cell damage or reactions; and (5 can be used as a photostimulator. These results clearly illustrate that the proposed color DIRI can significantly extend WSI modalities for biological applications.

  15. Reflections on the law applicable to international oil contracts

    OpenAIRE

    Otero García-Castrillón, Carmen

    2013-01-01

    Business activity in the hydrocarbon sector, involving the extraction of natural resources essential to maintain our modern lifestyle, begins with the negotiation of oil and gas exploration and exploitation contracts. Apart from the traditional role of the parties’ contractual autonomy, determining the legal regime of these contracts necessitates considering the role of international law, the development of oil sector-specific international rules (lex petrolea), and the impact of the imperati...

  16. Ultraviolet and yellow reflectance but not fluorescence is important for visual discrimination of conspecifics byHeliconius erato.

    Science.gov (United States)

    Finkbeiner, Susan D; Fishman, Dmitry A; Osorio, Daniel; Briscoe, Adriana D

    2017-04-01

    Toxic Heliconius butterflies have yellow hindwing bars that - unlike those of their closest relatives - reflect ultraviolet (UV) and long wavelength light, and also fluoresce. The pigment in the yellow scales is 3-hydroxy-dl-kynurenine (3-OHK), which is found in the hair and scales of a variety of animals. In other butterflies like pierids with color schemes characterized by independent sources of variation in UV and human-visible yellow/orange, behavioral experiments have generally implicated the UV component as most relevant to mate choice. This has not been addressed in Heliconius butterflies, where variation exists in analogous color components, but moreover where fluorescence due to 3-OHK could also contribute to yellow wing coloration. In addition, the potential cost due to predator visibility is largely unknown for the analogous well-studied pierid butterfly species. In field studies with butterfly paper models, we show that both UV and 3-OHK yellow act as signals for H. erato when compared with models lacking UV or resembling ancestral Eueides yellow, respectively, but attack rates by birds do not differ significantly between the models. Furthermore, measurement of the quantum yield and reflectance spectra of 3-OHK indicates that fluorescence does not contribute to the visual signal under broad-spectrum illumination. Our results suggest that the use of 3-OHK pigmentation instead of ancestral yellow was driven by sexual selection rather than predation. © 2017. Published by The Company of Biologists Ltd.

  17. A plastic total internal reflection-based photoluminescence device for enzymatic biosensors

    Science.gov (United States)

    Thakkar, Ishan G.

    Growing concerns for quality of water, food and beverages in developing and developed countries drive sizeable markets for mass-producible, low cost devices that can measure the concentration of contaminant chemicals in water, food, and beverages rapidly and accurately. Several fiber-optic enzymatic biosensors have been reported for these applications, but they exhibit very strong presence of scattered excitation light in the signal for sensing, requiring expensive thin-film filters, and their non-planar structure makes them challenging to mass-produce. Several other planar optical waveguide-based biosensors prove to be relatively costly and more fragile due to constituent materials and the techniques involved in their fabrication. So, a plastic total internal reflection (TIR)-based low cost, low scatter, field-portable device for enzymatic biosensors is fabricated and demonstrated. The design concept of the TIR-based photoluminescent enzymatic biosensor device is explained. An analysis of economical materials with appropriate optical and chemical properties is presented. PMMA and PDMS are found to be appropriate due to their high chemical resistance, low cost, high optical transmittance and low auto-fluorescence. The techniques and procedures used for device fabrication are discussed. The device incorporated a PMMA-based optical waveguide core and PDMS-based fluid cell with simple multi-mode fiber-optics using cost-effective fabrication techniques like molding and surface modification. Several techniques of robustly depositing photoluminescent dyes on PMMA core surface are discussed. A pH-sensitive fluorescent dye, fluoresceinamine, and an O2-sensitive phosphorescent dye, Ru(dpp) both are successfully deposited using Si-adhesive gel-based as well as HydroThane-based deposition methods. Two different types of pH-sensors using two different techniques of depositing fluoresceinamine are demonstrated. Also, the effect of concentration of fluoresceinamine-dye molecules

  18. Modelling of a total reflection X-ray fluorescence (TXRF) system ...

    African Journals Online (AJOL)

    The simulation of the different stages involved in x-ray fluorescence emissions was carried out by writing a suite of computer programs using FORTRAN programming language. These computer simulated XRF stages were then integrated together to generate a general robust model which was run with the digital visual ...

  19. Fluorescence contribution to the reflection of a photonic flux on a flat medium

    International Nuclear Information System (INIS)

    Bourdier, A.; Frey, J.J.; Saillard, Y.; Burgan, J.R.; Desfono, J.F.

    1988-12-01

    The albedo of a flat plane due to the sole fluorescence mechanism is calculated. Numerical evaluations are given considering an incident blackbody flux on a cold material. An optimum blackbody temperature is thus defined for a given material. The importance of induced effects is underlined [fr

  20. Development and characterization of a portable total reflection X-ray fluorescence system using a waveguide for trace elements analysis.

    Science.gov (United States)

    da Costa, Ana Cristina M; de Araújo, Ubiratan B; de Jesus, Edgar F O; Anjos, Marcelino J; Lopes, Ricardo T

    2014-01-01

    This paper presents a portable total reflection X-ray fluorescence system composed of a 15 W X-ray tube, with a gold anode, a waveguide constituted by two Perspex(®) parallel plates, a Si PIN detector and a quartz optical flat. The critical angle of the total reflection system was experimentally determined by measuring a zinc solution (100 mg/L). The accuracy of the system was checked using SRM 1577b Bovine Liver by NIST as standard reference material. We obtained the absolute detection limits of the following elements: P (450 ± 40 ng), S (200 ± 31 ng), K (30 ± 2.5 ng), Ca (19 ± 3.5 ng), Mn (4.1 ± 0.5 ng), Fe (3.6 ± 0.9 ng), Cu (3.3 ± 0.4 ng) and Zn (3.5 ± 0.3 ng). This paper shows that it is possible to produce total reflection X-ray fluorescence with very compact, efficient, low-cost and easy-to-handle instrumentation using a low-power X-ray tube and a Si PIN compact detector.

  1. Accompanying Partners of International Students: Reflections on Three Issues

    Science.gov (United States)

    Cui, Dan; Arthur, Nancy; Domene, José F.

    2017-01-01

    This paper reviews and critiques the existing literature on accompanying partners of international students (APIS), who are often an ignored population in programs and services for the internationalization of Canadian higher education. Particularly, we identify three issues. First, we argue that current research on this group overwhelmingly…

  2. Maintaining International Peace and Security: Reflections on Peace ...

    African Journals Online (AJOL)

    produced a dramatic growth in peacekeeping requirements since the end of the previous decade. The international response, mainly through the United Nations (UN), has been to promote preventive diplomacy and, in a number of cases, to conduct peace-support operations. In brief, this paper points out that each UN ...

  3. Pedagogical Reflections on Internalizing Geopolitical Representations in Print Media

    Science.gov (United States)

    Abdul-Jabbar, Wisam Khalid

    2015-01-01

    This essay explores how print media conceals implicit hegemonic texts that common readers unsuspectingly tend to internalize. These geopolitically infused texts are set to appropriate the reader's worldviews by sublimating the kind of perceptions and notions they want to promote. This paper raises questions and awareness about how academia…

  4. A method for thickness determination of thin films of amalgamable metals by total-reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Bennun, L.; Greaves, E.D.; Barros, H.; Diaz-Valdes, J.

    2009-01-01

    A method for thickness determination of thin amalgamable metallic films by total-reflection X-ray fluorescence (TXRF) is presented. The peak's intensity in TXRF spectra are directly related to the surface density of the sample, i.e. to its thickness in a homogeneous film. Performing a traditional TXRF analysis on a thin film of an amalgamated metal, and determining the relative peak intensity of a specific metal line, the layer thickness can be precisely obtained. In the case of gold thickness determination, mercury and gold peaks overlap, hence we have developed a general data processing scheme to achieve the most precise results.

  5. Effect of the refraction factor of a plastic fiber shell on the internal reflection coefficient

    International Nuclear Information System (INIS)

    Pkrksypkin, A.I.; Ponomarev, L.I.

    1992-01-01

    Results of pilot studies of the effect of refraction factor of plastic fiber shell on the coefficient of light internal reflection in the fiber are presented. It is pointed, that the shell does not absorb the light, but effects the surface layer of the fiber centre so, that dependence of the coefficient of internal reflection on refraction factor of the shell may be described using Fresnel formulae. It is shown, that coefficient of internal reflection decreases with the increase of refraction factor. Technique to determine volume length of scintillation light absorption in the fiber is suggested

  6. Reflections on the development of international nuclear law

    International Nuclear Information System (INIS)

    Lamm, Vanda

    2017-01-01

    Over the course of more than seven decades, treaty norms on the production and utilisation of nuclear energy have been developed, which together form a special section within international law. These norms are the consequence of the unique nature of the field, namely that on the one hand some aspects of the uses of nuclear energy should be covered by totally new and special norms (e.g. in the field of disarmament, seeking to eliminate or at least to control the spread of nuclear weapons, and nuclear weapons tests) and on the other hand that several traditional legal solutions were not suitable for the problems that emerged in connection with other uses of nuclear energy (like liability). In this article, three aspects of the development of that special section of international law will be explored, namely: the close connections between the regulation of peaceful and military uses of nuclear energy; the effects of nuclear catastrophes on the development of international nuclear legislation; and the interaction between soft law norms and binding norms in the area of nuclear law

  7. Scientific and technical challenges in remote sensing of plant canopy reflectance and fluorescence

    Czech Academy of Sciences Publication Activity Database

    Mishra, Kumud

    2009-01-01

    Roč. 11, č. 60 (2009), s. 2987-3004 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) OC08055; GA MŠk(CZ) OC09001 Institutional research plan: CEZ:AV0Z60870520 Keywords : LASER-INDUCED FLUORESCENCE * LEAF-AREA INDEX * LIGHT-USE EFFICIENCY Subject RIV: CE - Biochemistry Impact factor: 4.271, year: 2009

  8. Engineered drought tolerance in tomato plants is reflected in chlorophyll fluorescence emission

    Czech Academy of Sciences Publication Activity Database

    Mishra, Kumud; Iannacone, R.; Petrozza, A.; Mishra, Anamika; Armentano, N.; La Vecchia, G.; Trtílek, M.; Cellini, F.; Nedbal, Ladislav

    2012-01-01

    Roč. 182, SI (2012), s. 79-86 ISSN 0168-9452 R&D Projects: GA MŠk OC08055; GA MŠk 2B06068; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Chlorophyll fluorescence * Drought * High-throughput screening * Solanum lycopersicum * Transcription factor * Transgenic plant Subject RIV: EH - Ecology, Behaviour Impact factor: 2.922, year: 2012

  9. Nursing student voices: reflections on an international service learning experience.

    Science.gov (United States)

    Main, E Eve; Garrett-Wright, Dawn; Kerby, Molly

    2013-01-01

    For the past decade participation in service and experiential learning in higher education has increased. The purpose of this study was to explore the lived experience of BSN and MSN students participating in a multidisciplinary service-learning course in a rural, underserved village in Belize. Researchers analyzed student journals utilizing qualitative data analysis techniques. There were eight consistent themes found in the student journals. The findings indicate that international service learning opportunities increase students' awareness of their place in a global society and the potential contribution they can make in society. For the past decade, service and experiential learning in higher education, including nursing education, has become increasingly important. Simply put, service and experiential learning combine community service activities with a student's academic study for the sole purpose of enriching the academic experience. As faculty, we feel the goal of baccalaureate and graduate nursing education is to produce an educated professional who will become a responsible citizen.

  10. Prediction of Ba, Co and Ni for tropical soils using diffuse reflectance spectroscopy and X-ray fluorescence spectroscopy

    Science.gov (United States)

    Arantes Camargo, Livia; Marques Júnior, José; Reynaldo Ferracciú Alleoni, Luís; Tadeu Pereira, Gener; De Bortoli Teixeira, Daniel; Santos Rabelo de Souza Bahia, Angélica

    2017-04-01

    Environmental impact assessments may be assisted by spatial characterization of potentially toxic elements (PTEs). Diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF) are rapid, non-destructive, low-cost, prediction tools for a simultaneous characterization of different soil attributes. Although low concentrations of PTEs might preclude the observation of spectral features, their contents can be predicted using spectroscopy by exploring the existing relationship between the PTEs and soil attributes with spectral features. This study aimed to evaluate, in three geomorphic surfaces of Oxisols, the capacity for predicting PTEs (Ba, Co, and Ni) and their spatial variability by means of diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF). For that, soil samples were collected from three geomorphic surfaces and analyzed for chemical, physical, and mineralogical properties, and then analyzed in DRS (visible + near infrared - VIS+NIR and medium infrared - MIR) and XRF equipment. PTE prediction models were calibrated using partial least squares regression (PLSR). PTE spatial distribution maps were built using the values calculated by the calibrated models that reached the best accuracy using geostatistics. PTE prediction models were satisfactorily calibrated using MIR DRS for Ba, and Co (residual prediction deviation - RPD > 3.0), Vis DRS for Ni (RPD > 2.0) and FRX for all the studied PTEs (RPD > 1.8). DRS- and XRF-predicted values allowed the characterization and the understanding of spatial variability of the studied PTEs.

  11. Mechanistic aspects of fluorescent gold nanocluster internalization by live HeLa cells

    Science.gov (United States)

    Yang, Linxiao; Shang, Li; Nienhaus, G. Ulrich

    2013-01-01

    We have studied cellular uptake of ultrasmall fluorescent gold nanoclusters (AuNCs) by HeLa cells by confocal fluorescence microscopy in combination with quantitative image analysis. Water solubilized, lipoic acid-protected AuNCs, which had an overall hydrodynamic diameter of 3.3 nm and emitted fluorescence in the near-infrared region at ~700 nm, were observed to accumulate on the cell membrane prior to internalization. The internalization mechanisms were analyzed using inhibitors known to interfere with specific pathways. Cellular uptake of AuNCs is energy-dependent and involves multiple mechanisms: clathrin-mediated endocytosis and macropinocytosis appear to play a significant role, whereas the caveolin-mediated pathway contributes only to a lesser extent. Co-labeling of different cell organelles showed that intracellular trafficking of AuNCs mainly follows through endosomal pathways. The AuNCs were ultimately transferred to lysosomes; they were completely excluded from the nucleus even after 24 h.We have studied cellular uptake of ultrasmall fluorescent gold nanoclusters (AuNCs) by HeLa cells by confocal fluorescence microscopy in combination with quantitative image analysis. Water solubilized, lipoic acid-protected AuNCs, which had an overall hydrodynamic diameter of 3.3 nm and emitted fluorescence in the near-infrared region at ~700 nm, were observed to accumulate on the cell membrane prior to internalization. The internalization mechanisms were analyzed using inhibitors known to interfere with specific pathways. Cellular uptake of AuNCs is energy-dependent and involves multiple mechanisms: clathrin-mediated endocytosis and macropinocytosis appear to play a significant role, whereas the caveolin-mediated pathway contributes only to a lesser extent. Co-labeling of different cell organelles showed that intracellular trafficking of AuNCs mainly follows through endosomal pathways. The AuNCs were ultimately transferred to lysosomes; they were completely excluded

  12. Pedagogical Reflections on Internalizing Geopolitical Representations in Print Media

    Directory of Open Access Journals (Sweden)

    Wisam Khalid Abdul-Jabbar

    2015-06-01

    Full Text Available This essay explores how print media conceals implicit hegemonic texts that common readers unsuspectingly tend to internalize. These geopolitically infused texts are set to appropriate the reader’s worldviews by sublimating the kind of perceptions and notions they want to promote. This paper raises questions and awareness about how academia responds to these acts of internalization. These geopolitical texts, which dominate most of the print media and other resources, function at an imperceptible level to legitimize presuppositions and mould the world based on its own political imaginaries. To decode and interpret these largely shrewd texts requires a literacy skill that students need to acquire in different academic disciplines. This essay, therefore, explores how print media, such as newspapers and comics, attempts to legitimize knowledge through reports and stories that work at the subliminal level. Since all readers, students, instructors or researchers are vulnerable observers (Behar, 1996, because of our fallible human nature, the act of internalizing mediascaped knowledge becomes alarmingly simple and crucially effective on the way we are directed to perceive the world. By analogy, geopolitical texts are these id-instigated drives that the superego often suppresses and filters into dreams and fiction and yet they ominously somehow found their way out; they stealthily found expression and now they paint reality with their own biased colors. Can readers in the context be dream catchers? Cet article explore la manière dont les médias écrits dissimulent les textes hégémoniques implicites que les lecteurs ordinaires semblent assimiler à leur insu. Ces textes géopolitiquement insufflés sont appelés à approprier la vision du monde des lecteurs en sublimant le type de perceptions et de notions qu’ils souhaitent promouvoir. Cet article soulève des questions et sensibilise l’opinion sur la manière dont le monde universitaire r

  13. Development of a total reflection X-ray fluorescence spectrometer for ...

    Indian Academy of Sciences (India)

    Unknown

    rescence (EDXRF) analysis technique. In essence there are two major differences from conventional EDXRF: (i) the specimen is excited by the primary X-ray beam at a glancing angle less than the critical angle at which total external reflection occurs, and (ii) primary exciting radia- tion is incident on plane, polished surface, ...

  14. International Trade and Sustainable Development: Reflections on the Regulation Through the International Organizations

    OpenAIRE

    Barza, Eugênia Cristina Nilsen Ribeiro; Cerqueira, Wanilza Marques de Almeida

    2016-01-01

    The purpose of this study is to analyze the link between international trade and development. The regulation of international trade by international organizations will be explored. In the post-WTO scenario, there is the formation of a new governance in relation to international trade, with a tendency to appreciation of international relations at the Westphalian style. This phenomenon is worrying , especially in light of Agenda 2030 for Sustainable Development and the 17 Sustainable Developmen...

  15. 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.

  16. International Trade and Sustainable Development: Reflections on the Regulation Through the International Organizations

    Directory of Open Access Journals (Sweden)

    Eugênia Cristina Nilsen Ribeiro Barza

    2016-12-01

    Full Text Available The purpose of this study is to analyze the link between international trade and development. The regulation of international trade by international organizations will be explored. In the post-WTO scenario, there is the formation of a new governance in relation to international trade, with a tendency to appreciation of international relations at the Westphalian style. This phenomenon is worrying , especially in light of Agenda 2030 for Sustainable Development and the 17 Sustainable Development Goals established by the UN, which require a multilateral regulation of trade and participation of international organizations , particularly the WTO , for implementation their goals.

  17. Fluorescence characteristics of the fuel tracers triethylamine and trimethylamine for the investigation of fuel distribution in internal combustion engines.

    Science.gov (United States)

    Lind, Susanne; Aßmann, Simon; Zigan, Lars; Will, Stefan

    2016-03-01

    Laser-induced fluorescence based on fuel tracers like amines is a suitable measurement technique for mixing studies in internal combustion (IC) engines. Triethylamine has often been used in gasoline IC engines; however, no detailed fluorescence characterization for excitation at 263 or 266 nm is available. Trimethylamine (TMA) exhibits high potential as a gaseous fuel tracer but little information about TMA fluorescence is currently available. A picosecond laser source combined with a streak camera equipped with a spectrograph was used to determine the spectral fluorescence emission and fluorescence decay time of both tracers. The tracers were investigated at various temperatures and pressures in a calibration cell with nitrogen as bath gas. The results provide an in-depth understanding of the fluorescence characteristics of both tracers and allow assessment of their application to the investigation of fuel distribution in IC engines.

  18. Identification of a suitable internal control for fluorescence analysis on canine peripheral blood samples.

    Science.gov (United States)

    Riondato, F; Martini, V; Poggi, A; Rota, A; Comazzi, S; Sulce, M; Bruno, B; Borrelli, A; Miniscalco, B

    2016-04-01

    Reliable detection of fluorescence intensity (FI) by flow cytometry (FC) is fundamental. FI depends on instrument settings and sample processing procedures: thus, measurements should be done using internal controls with known FI. Commercially available beads-based standards are expensive, thus reducing their usability in the veterinary practice. Cell subsets with stable mean FI (MFI) within the population have been proposed as acceptable surrogates in human medicine. In veterinary medicine, no data exist about stability of antigen expression among different subjects or upon sample storage. The aim of the present study was to evaluate MFI variability of main lymphocytes antigens among the lymphoid cells within each subject, among different subjects, and upon 24-h storage, in order to identify the antigen most suitable as stable internal control in MFI analyses. Peripheral blood samples from 18 healthy dogs were analysed by FC within 3h from sampling to assess the expression of CD3, CD5, CD4, CD8, CD21 and cyCD79b using conjugated monoclonal antibodies. Analyses were restricted to the lymphoid population. Fluorescent microbeads were added to each tube, and antigen MFI was calculated as Relative Fluorescence Intensity RFI (CD/beads). Fluorescence histogram CV (fhCV) for each CD was regarded as an index of the variability of expression among lymphocytes within each subject (cell-to-cell variability); whereas the CV of RFI was regarded as an index of inter-subjects variability (dog-to-dog variability). In 11 cases, FC analyses were repeated after 24h storage at 4°C and RFI and CVs of fresh and stored samples were compared to assess variability linked to storage. CD4 was identified as the best antigen to be used as an internal control for MFI analyses in canine peripheral blood samples because of low cell-to-cell and dog-to-dog variability, and optimal stability upon 24-h storage. Blood samples from a second group of 21 healthy dogs were labelled only with CD4, in order

  19. Fish samples as bioindicator of environmental quality: synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    International Nuclear Information System (INIS)

    Vives, Ana Elisa Sirito de; Moreira, Silvana; Brienza, Sandra Maria Boscolo; Zucchi, Orgheda Luiza Araujo Domingues; Nascimento Filho, Virgilio Franco do Centro de Energia Nuclear na Agricultura , Piracicaba, SP; Brazil)

    2005-01-01

    In this study fish were used as bioindicators of environmental contamination. The species were collected in Piracicaba River, Sao Paulo state, Brazil and the toxic elements concentrations were determined in muscle tissue and viscus (liver, intestine and stomach) by Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF). Were determined the elements Ti, Cr, Mn, Fe, Ni, Cu, Zn and Ba. The results were compared with values established by Brazilian Legislation for general food. The elements concentrations evidenced potential risk to human health and environmental quality alteration of the studied area. The measurements were realized at the 'Laboratorio Nacional de Luz Sincrotron' (LNLS) located in Campinas, Sao Paulo State, Brazil. (author)

  20. Fish samples as bioindicator of environmental quality: synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Brienza, Sandra Maria Boscolo [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil). Faculdade de Ciencias Matematicas, da Natureza e de Tecnologia da Informacao]. E-mail: sbrienza@unimep.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio Franco do [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: virgilio@cena.usp.br

    2005-07-01

    In this study fish were used as bioindicators of environmental contamination. The species were collected in Piracicaba River, Sao Paulo state, Brazil and the toxic elements concentrations were determined in muscle tissue and viscus (liver, intestine and stomach) by Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF). Were determined the elements Ti, Cr, Mn, Fe, Ni, Cu, Zn and Ba. The results were compared with values established by Brazilian Legislation for general food. The elements concentrations evidenced potential risk to human health and environmental quality alteration of the studied area. The measurements were realized at the 'Laboratorio Nacional de Luz Sincrotron' (LNLS) located in Campinas, Sao Paulo State, Brazil. (author)

  1. Multielemental analysis in organic products and seed of linum by X-ray total reflection fluorescence with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Serpa, Renata F.B.; Jesus, Edgar F.O. de; Lopes, Ricardo T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Lab. de Instrumentacao Nuclear]. E-mail: renata@lin.ufrj.br; Carmo, Maria da Graca T. do [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Nutricao; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil]. E-mail: silvana@fec.com.br

    2005-07-01

    The main goal of this study is to determining the trace and major elements levels in organic seeds samples, like soy, rice, bean and in Brazilian and Canadian linum seed by X-ray Total Reflection Fluorescence with Synchrotron Radiation (SR-TXRF). The measurements were carried out in the XRF beamline at the Light Synchrotron National Laboratory (Campinas, Brazil). The organic soy presented major concentrations of P, Ca, Ti, Fe, Ni, Cu, Zn, Br, Rb and Sr than organic bean and rice. Brazilian linum samples presented higher concentrations of S, P, Ca, Ni, Cu, Sr, Zr and Mo than Canadian one, even than organic samples. However potassium, iron and zinc were more pronounced in the Canadian seed of linum (author)

  2. Determination of mercury in seawater by total reflection x-ray fluorescence spectrometry after an electrochemical preconcentration method

    International Nuclear Information System (INIS)

    Ritschel, A.; Chinea Cano, E.; Wobrauschek, P.; Kuntner, C.; Durakbasa, M.N.

    2000-01-01

    A new combined method of electrodeposition of trace elements on metallic plates with subsequent total-reflection x-ray fluorescence spectrometry (TXRF) is proposed for the determination of trace metals in natural waters. The elements of interest are electroplated on highly polished niobium discs which are used as sample carriers for the TXRF measurement. The electrochemical preconcentration is performed in a flow cell under a controlled working electrode potential. The preconcentration step involves only very little manipulation which minimizes the risk of contamination of the sample. The method was investigated by analyzing inorganic mercury in sea water. A detection limit of 7 ngl -1 could be achieved for mercury in a 40 ml sea water sample. (author)

  3. Seasonal variation in trace and minor elements in Brazilian honey by total reflection X-ray fluorescence.

    Science.gov (United States)

    de Oliveira Resende Ribeiro, Roberta; Mársico, Eliane Teixeira; da Silva Carneiro, Carla; Simoes, Julia Siqueira; da Silva Ferreira, Micheli; de Jesus, Edgar Francisco Oliveira; Almeida, Eduardo; Junior, Carlos Adam Conte

    2015-03-01

    Honey is used as an alternative medicine and is a constituent of a healthy diet worldwide. Its composition is associated with botanical origin and, to some extent, geographical origin because soil and climate characteristics determine the melliferous flora. Also, the elements content in honey samples could give an indication of environmental pollution or geographical origin. The main purpose of this study was to evaluate seasonal patterns of essential elements of Brazilian honey. Honey was collected during spring, summer, autumn, and winter for 2 years to quantify K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, and Sr using total reflection X-ray fluorescence spectroscopy (TXRF). Our results indicate no seasonal differences in concentration of Cr, Ni, Se, and Ti, although there were significant seasonal patterns in the composition of essential elements in honey, with higher concentrations of minor and trace elements, especially K and Ca of samples collected in spring and summer.

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

    Science.gov (United States)

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

    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.

  5. Practical guidelines for best practice on Total Reflection X-ray Fluorescence spectroscopy: Analysis of aqueous solutions

    Science.gov (United States)

    Riaño, Sofía; Regadío, Mercedes; Binnemans, Koen; Vander Hoogerstraete, Tom

    2016-10-01

    Despite the fact that Total Reflection X-ray Fluorescence (TXRF) is becoming more and more popular as a quantification technique in analytical chemistry due to its simplicity and robustness, there are still some key aspects related to the sample preparation that need to be improved. In this work, the effect of different parameters is investigated: measurement time, carrier position, sample volume and sample drying time. The measurement time and the sample volume on the carriers mainly affect the recovery rate and relative standard deviation of the quantified metal from aqueous solutions. The most important parameters that play a fundamental role in the calibration of a TXRF machine such as choice of the standard element and concentration ratio between the analyte and the standard are discussed. Practical and easy guidelines for the correct preparation of aqueous samples are presented. These can be used by both less and more experienced TXRF users, interested in measuring metal ion concentrations in aqueous samples.

  6. Worldwide distribution of Total Reflection X-ray Fluorescence instrumentation and its different fields of application: A survey

    Science.gov (United States)

    Klockenkämper, Reinhold; von Bohlen, Alex

    2014-09-01

    A survey was carried out with users and manufacturers of Total Reflection X-ray Fluorescence instrumentation in order to demonstrate the worldwide distribution of TXRF equipment and the different fields of applications. In general, TXRF users come from universities and scientific institutes, from working places at synchrotron beam-lines, or laboratories in semiconductor fabs. TXRF instrumentation is distributed in more than 50 countries on six continents and is applied at about 200 institutes and laboratories. The number of running desktop instruments amounts to nearly 300 units. About 60 beamlines run working places dedicated to TXRF. About 300 floor-mounted instruments are estimated to be used in about 150 fabs of the semiconductor industry. In total, 13 different fields of applications could be registered statistically from three different aspects.

  7. Total reflection X-ray fluorescence analysis of light elements with synchrotron radiation and special X-ray tubes

    International Nuclear Information System (INIS)

    Streli, C.; Wobrauschek, P.; Bauer, V.; Kregsamer, P.; Goergl, R.; Pianetta, P.; Ryon, R.; Pahlke, S.; Fabry, L.

    1997-01-01

    Total reflection X-ray fluorescence analysis (TXRF) of light elements, such as C, O and Al (atomic numbers 5-13) generally has poor sensitivity and detection limits due to poor excitation and low fluorescent yields. Special excitation sources are necessary to compensate for these physical limitations. Synchrotron radiation is the ideal source for TXRF due to its high intensity and wide spectral range extending into the low energy region required for light elements. For more routine use, special X-ray tubes can be constructed. Experiments have been performed at the Standford Synchrotron Radiation Laboratory (SSRL) using beamline III-4, which is specially designed for the sue of low energy photons. Light elements on Si wafers have been analyzed, leading to detection limits below 100 fg for Na, Mg and Al, which corresponds to about 10 9 atoms. A new vacuum chamber is introduced meeting the requirements of wafer handling without the risk of contamination and offering the possibility of scanning a certain area of the wafer. Boron was detected on a wafer with 10 14 atoms cm -2 implanted in the surface layer. A special windowless X-ray tube with Mo, Al and Si as anode materials was also tested. With the optimization of anode geometry, beam path and excitation conditions, a detection limit of 5 pg (corresponds to 10 11 atoms) for Al was achieved. (Author)

  8. Total reflection X-ray fluorescence analysis of light elements with synchrotron radiation and special X-ray tubes

    Energy Technology Data Exchange (ETDEWEB)

    Streli, C.; Wobrauschek, P.; Bauer, V.; Kregsamer, P.; Goergl, R. [Atominstitut der Oesterreichischen Universitaeten, Wien (Austria); Pianetta, P. [Stanford Synchrotron Radiation Lab. (Canada); Ryon, R. [Lawrence Livermore National Lab. CA (United States); Pahlke, S.; Fabry, L. [Wacker Siltronic AG, Burghausen (Germany)

    1997-06-20

    Total reflection X-ray fluorescence analysis (TXRF) of light elements, such as C, O and Al (atomic numbers 5-13) generally has poor sensitivity and detection limits due to poor excitation and low fluorescent yields. Special excitation sources are necessary to compensate for these physical limitations. Synchrotron radiation is the ideal source for TXRF due to its high intensity and wide spectral range extending into the low energy region required for light elements. For more routine use, special X-ray tubes can be constructed. Experiments have been performed at the Standford Synchrotron Radiation Laboratory (SSRL) using beamline III-4, which is specially designed for the sue of low energy photons. Light elements on Si wafers have been analyzed, leading to detection limits below 100 fg for Na, Mg and Al, which corresponds to about 10{sup 9}atoms. A new vacuum chamber is introduced meeting the requirements of wafer handling without the risk of contamination and offering the possibility of scanning a certain area of the wafer. Boron was detected on a wafer with 10{sup 14} atoms cm{sup -2} implanted in the surface layer. A special windowless X-ray tube with Mo, Al and Si as anode materials was also tested. With the optimization of anode geometry, beam path and excitation conditions, a detection limit of 5 pg (corresponds to 10{sup 11} atoms) for Al was achieved. (Author).

  9. Feasibility study of total reflection X-ray fluorescence analysis using a liquid metal jet X-ray tube

    Science.gov (United States)

    Maderitsch, A.; Smolek, S.; Wobrauschek, P.; Streli, C.; Takman, P.

    2014-09-01

    Total reflection X-ray spectroscopy (TXRF) is a powerful analytical technique for qualitative and quantitative analysis of trace and ultratrace elements in a sample with lower limits of detection (LLDs) of pg/g to ng/g in concentration and absolute high fg levels are attainable. Several X-ray sources, from low power (few W), 18 kW rotating anodes to synchrotron radiation, are in use for the excitation and lead accordingly to their photon flux delivered on the sample the detection limits specified. Not only the power, but also the brilliance and focal shape are of importance for TXRF. A microfocus of 50-100 μm spot size or the line focus of diffraction tubes is best suited. Excillum developed a new approach in the design of a source: the liquid metal jet anode. In this paper the results achieved with this source are described. A versatile TXRF spectrometer with vacuum chamber designed at Atominstitut was used for the experiments. A multilayer monochromator selecting the intensive Ga-Kα radiation was taken and the beam was collimated by 50 μm slits. Excellent results regarding geometric beam stability, high fluorescence intensities and low background were achieved leading to detection limits in the high fg range for Ni. A 100 mm2 silicon drift detector (SDD) collimated to 80 mm2 was used to collect the fluorescence radiation. The results from measurements on single element samples are presented.

  10. A Ratiometric Fluorescent Sensor for Cd2+ Based on Internal Charge Transfer

    Directory of Open Access Journals (Sweden)

    Dandan Cheng

    2017-11-01

    Full Text Available This work reports on a novel fluorescent sensor 1 for Cd2+ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron-1,2-bis[(1H-pyrrol-2-ylmethylene]hydrazine (Me4BOPHY, which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethylbenzenamine. Sensor 1 has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT transition of molecule 1. Binding of Cd2+ ion quenches the ICT transition, but turns on the π − π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD was projected down to 0.77 ppb, which is far below the safety value (3 ppb set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd2+ in comparison to other interferent metal ions.

  11. Spectral Separation of Quantum Dots within Tissue Equivalent Phantom Using Linear Unmixing Methods in Multispectral Fluorescence Reflectance Imaging

    Directory of Open Access Journals (Sweden)

    Ebrahim Najafzadeh

    2012-09-01

    Full Text Available Introduction Non-invasive Fluorescent Reflectance Imaging (FRI is used for accessing physiological and molecular processes in biological media. The aim of this article is to separate the overlapping emission spectra of quantum dots within tissue-equivalent phantom using SVD, Jacobi SVD, and NMF methods in the FRI mode. Materials and Methods In this article, a tissue-like phantom and an optical setup in reflectance mode were developed. The algorithm of multispectral imaging method was then written in Matlab environment. The setup included the diode-pumped solid-state lasers at 479 nm, 533 nm, and 798 nm, achromatic telescopic, mirror, high pass and low pass filters, and EMCCD camera. The FRI images were acquired by a CCD camera using band pass filter centered at 600 nm and high pass max at 615 nm for the first region and high pass filter max at 810 nm for the second region. The SVD and Jacobi SVD algorithms were written in Matlab environment and compared with a Non-negative Matrix Factorization (NMF and applied to the obtained images. Results PSNR, SNR, CNR of SVD, and NMF methods were obtained as 39 dB, 30.1 dB, and 0.7 dB, respectively. The results showed that the difference of Jacobi SVD PSNR with PSNR of NMF and modified NMF algorithm was significant (p

  12. Elemental concentration analysis in the brain of young and old Wistar rats by total reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Serpa, Renata F.B.; Jesus, Edgar F.O. de; Lopes, Ricardo T.; Anjos, Marcelino J. dos; Carmo, Maria G.T. do; Rocha, Monica S.; Moreira, Silvana; Martinez, Ana M.B.

    2007-01-01

    It is well known that aging is associated with neurobehavioral deficits. The aging process of human brain is characterized by progressive neuronal loss. Furthermore, certain brain areas are more vulnerable to neuronal degeneration than others, reflecting an altered resistance to stress of the tissue itself and/or the lack of adequate immunological defense mechanisms in these regions. About the elemental levels in the brain, it is known that the excess ou deficiency of some elements are toxic for human healthy, being also related to several neurodegenerative diseases. In this way, the main goal of this work was to determine the elemental concentration in the hippocampus of young and old male (n = 10) and female (n = 10) Wistar rats by total reflection X-ray fluorescence spectrometry with synchrotron radiation (SR-TXRF). These measurements were carried out at XRF beam line at Light Synchrotron Brazilian Laboratory, Campinas, Brazil. About the results, we could observe that Al, Fe, Cu, Zn and Br levels were higher in the hippocampus of the old female rats than the young ones. On the other hand, only Cu levels were higher in the hippocampus of the old male rats than the young ones. Therefore, the aging of the hippocampus of the female rats can be characterized by an accumulate for Al, Fe, Cu, Zn and Br. The excess in these elements levels are also associated with several neurodegenerative disorders, such as Alzheimer' disease, Parkinson's disease and Huntington's disease. (author)

  13. Integrating Solar Induced Fluorescence and the Photochemical Reflectance Index for Estimating Gross Primary Production in a Cornfield

    Directory of Open Access Journals (Sweden)

    Yen-Ben Cheng

    2013-12-01

    Full Text Available The utilization of remotely sensed observations for light use efficiency (LUE and tower-based gross primary production (GPP estimates was studied in a USDA cornfield. Nadir hyperspectral reflectance measurements were acquired at canopy level during a collaborative field campaign conducted in four growing seasons. The Photochemical Reflectance Index (PRI and solar induced chlorophyll fluorescence (SIF, were derived. SIF retrievals were accomplished in the two telluric atmospheric oxygen absorption features centered at 688 nm (O2-B and 760 nm (O2-A. The PRI and SIF were examined in conjunction with GPP and LUE determined by flux tower-based measurements. All of these fluxes, environmental variables, and the PRI and SIF exhibited diurnal as well as day-to-day dynamics across the four growing seasons. Consistent with previous studies, the PRI was shown to be related to LUE (r2 = 0.54 with a logarithm fit, but the relationship varied each year. By combining the PRI and SIF in a linear regression model, stronger performances for GPP estimation were obtained. The strongest relationship (r2 = 0.80, RMSE = 0.186 mg CO2/m2/s was achieved when using the PRI and SIF retrievals at 688 nm. Cross-validation approaches were utilized to demonstrate the robustness and consistency of the performance. This study highlights a GPP retrieval method based entirely on hyperspectral remote sensing observations.

  14. Determination of heavy metals in macrozoobenthos from the rivers Tisza and Szamos by total reflection X-ray fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Woelfl, S. [Universidad Austral de Chile, Instituto de Zoologia, Casilla 567, Valdivia (Chile)]. E-mail: swoelfl@uach.cl; Mages, M. [Helmhotz Centre for Environmental Research (UFZ), Department of River Ecology, Brueckstrasse 3a, D-39114, Magdeburg (Germany); Ovari, M. [Ovari, M. Eoetvoes University, Department of Organic Chemistry, H-1117, Budapest, Pazmany P. stny. 1/a (Hungary); Geller, W. [Helmhotz Centre for Environmental Research (UFZ), Department of River Ecology, Brueckstrasse 3a, D-39114, Magdeburg (Germany)

    2006-11-15

    In 2000, accidents in the Romanian mining industry in key catchment areas led to heavy metal contamination of the Hungarian rivers Tisza and Szamos resulting in substantial heavy metal loads in several sediments of the upper river basins. This enhanced metal content might have been bioaccumulated in benthic organisms during the following years. Therefore, the aim of this study was to test, whether the zoobenthic fauna showed an enhanced metal content 3 years after the industrial accident. Macrozoobenthic insect larvae (chironomids) were sampled 100 m below and above the confluent site of the rivers Tisza and Szamos during summer 2003 and for comparison purpose also in the river Maros, a tributary of the Tisza river, during 2005. In order to determine their heavy metal content, single specimens were prepared and analysed by Total Reflection X-ray Fluorescence Spectrometry (TRXF) according to the modified dry method. Fe was much lower and Mn and Zn much higher concentrated in benthos from the more contaminated Szamos river compared to the Tisza and Maros rivers. In this sense, the benthic organisms reflected very well the enhanced metal concentrations in the contaminated rivers being suitable as bioindicators of metal contamination. However, the sediment bioaccumulation factor was low at all sampling sites indicating a low bioavailability of trace metals for benthic organisms.

  15. Determination of heavy metals in macrozoobenthos from the rivers Tisza and Szamos by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Woelfl, S.; Mages, M.; Óvári, M.; Geller, W.

    2006-11-01

    In 2000, accidents in the Romanian mining industry in key catchment areas led to heavy metal contamination of the Hungarian rivers Tisza and Szamos resulting in substantial heavy metal loads in several sediments of the upper river basins. This enhanced metal content might have been bioaccumulated in benthic organisms during the following years. Therefore, the aim of this study was to test, whether the zoobenthic fauna showed an enhanced metal content 3 years after the industrial accident. Macrozoobenthic insect larvae (chironomids) were sampled 100 m below and above the confluent site of the rivers Tisza and Szamos during summer 2003 and for comparison purpose also in the river Maros, a tributary of the Tisza river, during 2005. In order to determine their heavy metal content, single specimens were prepared and analysed by Total Reflection X-ray Fluorescence Spectrometry (TRXF) according to the modified dry method. Fe was much lower and Mn and Zn much higher concentrated in benthos from the more contaminated Szamos river compared to the Tisza and Maros rivers. In this sense, the benthic organisms reflected very well the enhanced metal concentrations in the contaminated rivers being suitable as bioindicators of metal contamination. However, the sediment bioaccumulation factor was low at all sampling sites indicating a low bioavailability of trace metals for benthic organisms.

  16. Intraocular light scatter, reflections, fluorescence and absorption: what we see in the slit lamp.

    Science.gov (United States)

    van den Berg, Thomas J T P

    2018-01-01

    Much knowledge has been collected over the past 20 years about light scattering in the eye- in particular in the eye lens- and its visual effect, called straylight. It is the purpose of this review to discuss how these insights can be applied to understanding the slit lamp image. The slit lamp image mainly results from back scattering, whereas the effects on vision result mainly from forward scatter. Forward scatter originates from particles of about wavelength size distributed throughout the lens. Most of the slit lamp image originates from small particle scatter (Rayleigh scatter). For a population of middle aged lenses it will be shown that both these scatter components remove around 10% of the light from the direct beam. For slit lamp observation close to the reflection angles, zones of discontinuity (Wasserspalten) at anterior and posterior parts of the lens show up as rough surface reflections. All these light scatter effects increase with age, but the correlations with age, and also between the different components, are weak. For retro-illumination imaging it will be argued that the density or opacity seen in areas of cortical or posterior subcapsular cataract show up because of light scattering, not because of light loss. NOTES: (1) Light scatter must not be confused with aberrations. Light penetrating the eye is divided into two parts: a relatively small part is scattered, and removed from the direct beam. Most of the light is not scattered, but continues as the direct beam. This non-scattered part is the basis for functional imaging, but its quality is under the control of aberrations. Aberrations deflect light mainly over small angles (light scatter is important because of the straylight effects over large angles (>1°), causing problems like glare and hazy vision. (2) The slit lamp image in older lenses and nuclear cataract is strongly influenced by absorption. However, this effect is greatly exaggerated by the light path lengths concerned. This

  17. Total internal reflection resonance light scattering at solid/liquid interfaces.

    Science.gov (United States)

    Tang, Yao-Ji; Chen, Ying; Yao, Min-Na; Li, Yao-Qun

    2008-08-05

    Total internal reflection (TIR) technique is an interface-specific tool and resonance light scattering (RLS) is of high sensitivity. The combination of both approaches is introduced into the solid/liquid interface for the first time. The behaviors of mixture of TPPS and BSA at the interface have been studied with total internal reflection resonance light scattering (TIR-RLS). The preliminary experimental results indicate that TIR-RLS is a good approach to study the interaction and distinguish the states of macromolecules at the solid/liquid interface.

  18. Israeli medical education: international perspectives, and reflections on challenges and changes.

    Science.gov (United States)

    Katz, David R

    2016-01-01

    Medical education is a dynamic and continually evolving process, some of which is style, and some of which is linked to changing perspectives in medical practice. A paper by Reis et al., taken in conjunction with the recent paper from an ad hoc International Review Committee (Schoenbaum et al.), provides a reflective view of where Israeli medical education stood in 2014 and places it in an international perspective. Reis at al also take this further, showing that in Israel change is occurring as a result of this review and comment on a number of important issues where further reflection, discussion, and work is required.

  19. Slow-light total-internal-reflection switch with bending angle of 30 deg.

    Science.gov (United States)

    Fuchida, Ayumi; Matsutani, Akihiro; Koyama, Fumio

    2011-07-15

    Slowing light in a Bragg reflector waveguide is used to miniaturize optical waveguide switches. We can realize a giant equivalent refractive index change induced by carrier injection near a cutoff wavelength due to its large waveguide dispersion. We fabricate and characterize a reflection-type slow-light switch. Input light is reflected at the off state due to an equivalent index difference between an oxide aperture and an oxide region, while it passes through at the on state, since the equivalent index difference is compensated using carrier injection. We obtained a large bending angle of 30° with total internal reflection of slow light. © 2011 Optical Society of America

  20. Total Reflection X-ray Fluorescence Analysis (TXRF) using the high flux SAXS camera

    CERN Document Server

    Wobrauschek, P; Pepponi, G; Bergmann, A; Glatter, O

    2002-01-01

    Combining the high photon flux from a rotating anode X-ray tube with an X-ray optical component to focus and monochromatize the X-ray beam is the most promising instrumentation for best detection limits in the modern XRF laboratory. This is realized by using the design of a high flux SAXS camera in combination with a 4 kW high brilliant rotating Cu anode X-ray tube with a graded elliptically bent multilayer and including a new designed module for excitation in total reflection geometry within the beam path. The system can be evacuated thus reducing absorption and scattering of air and removing the argon peak in the spectra. Another novelty is the use of a Peltier cooled drift detector with an energy resolution of 148 eV at 5.9 keV and 5 mm sup 2 area. For Co detection limits of about 300 fg determined by a single element standard have been achieved. Testing a real sample NIST 1643d led to detection limits in the range of 300 ng/l for the medium Z.

  1. VIS/NIR reflectance and fluorescence spectrometric studies of minerals, water, organics and biomarkers in MoonMars analogue samples

    Science.gov (United States)

    Vos, Heleen; Foing, Bernard; Kołodziejczyk, Agata; Vago, Jorge; Harasymczuk, Matt

    2017-04-01

    This study focuses on the detection and characterisation of elements, minerals, volatiles and organics using reflectance spectrometry. The goal is to create a calibration method to enable the use of spectrometers on analogue Moon/Mars missions and on a lander. For this study we use measurements that are done in the VIS and NIR spectrum, as well as fluorescence using different spectrometers. The first part of the study consists of measurements that are performed in a laboratory to create a calibration method. Different rock samples and soils are analysed and the reflectance and absorption of minerals, water, organics and biomarkers are measured. Also the influence of the grain size, light source and surroundings is being determined. An experiment on the reflectance spectra of plant growth in different soils is also done to determine the possibilities of detecting the presence of chlorophyll and other biomarkers, and to diagnose the growth and health of a plant. This analysis can result in a monitoring method for a Moon greenhouse, but also for general surface analysis. Using VIS and NIR spectrometry has a couple of advantages, one being the fact that measurements require no sample preparation, and also the small size of the spectrometer makes it an easy tool for different analyses on board space missions. However, VIS and NIR spectroscopy have detection limits which makes only certain characteristics detectable. Besides laboratory measurements, the different spectroscopy methods are tested during a field campaign in the Eifel, Germany. During this campaign we can determine the functionality of the spectrometer in the field and on a lander and the problems that can rise when a spectrometer is controlled from a distant or by a person who is not trained in using spectroscopy. These laboratory and field measurements can help in the scientific preparation for instruments on ExoMars rover, future MoonMars lander missions and for the MoonVillage.

  2. Celebrating international collaboration: reflections on the first Virtual International Practice Development Conference

    Directory of Open Access Journals (Sweden)

    Moira Stephens

    2016-11-01

    Full Text Available This article reports on the first Virtual International Practice Development Conference, held in May 2015 to celebrate International Nurses Day. The article describes key aspects of its planning, offers a flavour of the event itself and sets out an evaluation, including learning points and recommendations to assist with planning similar events in the future. Central to our learning are: The need for practice developers to grasp skills in technology associated with virtual space The need to embrace virtual space itself as another means by which creative and communicative spaces can be established for active learning and practice development activities The potential advantages that international virtual engagement has over face-to-face national or international engagement The delivery of this virtual event made a significant international contribution to global practice development activity within the International Practice Development Collaborative and to enabling practice developers to connect and celebrate on a more global basis. Implications for practice: Virtual space technology skills can assist with sharing and translating practice development research, innovations and critical commentary Virtual space can provide an adjunct to creative and communicative learning spaces Global networking opportunities can be developed and enhanced through the use of virtual space technology Practice developers need to role model the use of virtual technologies

  3. Feasibility study of total reflection X-ray fluorescence analysis using a liquid metal jet X-ray tube

    Energy Technology Data Exchange (ETDEWEB)

    Maderitsch, A.; Smolek, S. [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Wien (Austria); Wobrauschek, P., E-mail: wobi@ati.ac.at [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Wien (Austria); Streli, C. [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Wien (Austria); Takman, P. [Excillum AB, Finlandsgatan 14, 164 74 Kista (Sweden)

    2014-09-01

    Total reflection X-ray spectroscopy (TXRF) is a powerful analytical technique for qualitative and quantitative analysis of trace and ultratrace elements in a sample with lower limits of detection (LLDs) of pg/g to ng/g in concentration and absolute high fg levels are attainable. Several X-ray sources, from low power (few W), 18 kW rotating anodes to synchrotron radiation, are in use for the excitation and lead accordingly to their photon flux delivered on the sample the detection limits specified. Not only the power, but also the brilliance and focal shape are of importance for TXRF. A microfocus of 50–100 μm spot size or the line focus of diffraction tubes is best suited. Excillum developed a new approach in the design of a source: the liquid metal jet anode. In this paper the results achieved with this source are described. A versatile TXRF spectrometer with vacuum chamber designed at Atominstitut was used for the experiments. A multilayer monochromator selecting the intensive Ga-Kα radiation was taken and the beam was collimated by 50 μm slits. Excellent results regarding geometric beam stability, high fluorescence intensities and low background were achieved leading to detection limits in the high fg range for Ni. A 100 mm{sup 2} silicon drift detector (SDD) collimated to 80 mm{sup 2} was used to collect the fluorescence radiation. The results from measurements on single element samples are presented. - Highlights: • Using a new X-ray source for TXRF • Liquid metal jet X-ray source from Excillum • Offers improvements for lab based TXRF spectrometers • Can also be important for related techniques.

  4. Creating Comic Books in Nigeria: International Reflections on Literacy, Creativity, and Student Engagement

    Science.gov (United States)

    Bitz, Michael; Emejulu, Obiajulu

    2016-01-01

    This article is an international reflection on literacy, creativity, and student engagement. The authors collaborated to help Nigerian youths and their teachers develop, design, and share original comic books. By leveraging student engagement for literacy learning, the authors highlighted the crucial role of creativity in the classroom. The…

  5. Measurement of the Longitudinal Shift of Radiation at Total Internal Reflection by Microwave Techniques

    Science.gov (United States)

    Akylas, Victor; And Others

    1976-01-01

    Describes a method to experimentally determine the longitudinal shift of a microwave beam at total internal reflection. Suggests that the activity be incorporated into an undergraduate laboratory program due to its ease in set-up and clarity of results. (CP)

  6. Four Members of the International Adult and Continuing Education Hall of Fame Reflect on Their Careers

    Science.gov (United States)

    Sandmann, Lorilee R.; Miller, Gary E.

    2011-01-01

    Drawing on collective experience of over 200 years, four members of the International Adult and Continuing Education Hall of Fame were panelists in a session at the 2010 National Outreach Scholarship Conference. As the panelists reflected on careers in the field of adult and continuing education, four sustaining themes emerged: commitment,…

  7. Symbolic Uses of Evaluation in the International Aid Sector: Arguments for Critical Reflection

    Science.gov (United States)

    McNulty, James

    2012-01-01

    Significant progress has been made in recent years to improve the quality of the evaluation of international aid. Increasingly, this includes an interest in improving the way evaluations are used to improve policies and programmes. However, the prevalence of symbolic use--a phenomenon that is often mentioned but rarely studied--reflects an…

  8. Reflections

    Indian Academy of Sciences (India)

    pumped' by displacement of the center of gravity of the person sitting or standing on it. Back in Europe (1925). In the fall of 1925 I read in some journal that an International Congress on Mechanics was to be held in. Zurichthe following autumn.

  9. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  10. Attenuated total internal reflection infrared microspectroscopic imaging using a large-radius germanium internal reflection element and a linear array detector.

    Science.gov (United States)

    Patterson, Brian M; Havrilla, George J

    2006-11-01

    The number of techniques and instruments available for Fourier transform infrared (FT-IR) microspectroscopic imaging has grown significantly over the past few years. Attenuated total internal reflectance (ATR) FT-IR microspectroscopy reduces sample preparation time and has simplified the analysis of many difficult samples. FT-IR imaging has become a powerful analytical tool using either a focal plane array or a linear array detector, especially when coupled with a chemometric analysis package. The field of view of the ATR-IR microspectroscopic imaging area can be greatly increased from 300 x 300 microm to 2500 x 2500 microm using a larger internal reflection element of 12.5 mm radius instead of the typical 1.5 mm radius. This gives an area increase of 70x before aberrant effects become too great. Parameters evaluated include the change in penetration depth as a function of beam displacement, measurements of the active area, magnification factor, and change in spatial resolution over the imaging area. Drawbacks such as large file size will also be discussed. This technique has been successfully applied to the FT-IR imaging of polydimethylsiloxane foam cross-sections, latent human fingerprints, and a model inorganic mixture, which demonstrates the usefulness of the method for pharmaceuticals.

  11. Analysis in crab tissues and in sediment of estuary from Iguape (Sao Paulo, Brazil) by total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Salvador, Marcos J.; Sawazaki, David T.A.; Zucchi, Orgheda L.A. Domingues; Vives, Ana Elisa S. de; Hattori, Gustavo Y.

    2007-01-01

    We report the use of Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF) as a technique for macro, micro and trace elements determination in the tissues of the crab Ulcides cordatus and in the sediments from the Iguape estuary (Sao Paulo, Brazil) for environmental pollution control and toxicological evaluation. The analyses were performed on the U. cordatus (muscles and hepatopancreas) and on sediments from 24 sites of the Iguape estuary (Sao Paulo, Brazil). Tissues and sediments samples were analyzed by SRTXRF after digestion in an open system, using Ga as internal standard. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, and Ba were the elements detected in crab hepatopancreas at concentration ranging from 0.516 (Mn) to 2061 (K) mug/g. Muscles samples presented the elements K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Br and Sr at concentrations ranging from 0.043 (Ni) to 1917 (K) mug/g. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Sn, Ce, and Pb were the elements detected in the sediment samples with concentration between 3.8 (Cu) and 14628 (Fe)mug/g. (author)

  12. Analysis in crab tissues and in sediment of estuary from Iguape (Sao Paulo, Brazil) by total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, Marcos J. [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil)], E-mail: mjsalvador1531@yahoo.com.br; Sawazaki, David T.A.; Zucchi, Orgheda L.A. Domingues [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas], E-mail: david_tatsuo@hotmail.com, E-mail: olzucchi@fcfrp.usp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo], E-mail: aesvives@unimep.br; Hattori, Gustavo Y. [Universidade Federal do Amazonas, Benjamin Constant (Brazil). Faculdade de Ciencias Agrarias], E-mail: hattori@ufam.edu.br

    2007-07-01

    We report the use of Synchrotron Radiation Total Reflection X-Ray Fluorescence analysis (SR-TXRF) as a technique for macro, micro and trace elements determination in the tissues of the crab Ulcides cordatus and in the sediments from the Iguape estuary (Sao Paulo, Brazil) for environmental pollution control and toxicological evaluation. The analyses were performed on the U. cordatus (muscles and hepatopancreas) and on sediments from 24 sites of the Iguape estuary (Sao Paulo, Brazil). Tissues and sediments samples were analyzed by SRTXRF after digestion in an open system, using Ga as internal standard. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, and Ba were the elements detected in crab hepatopancreas at concentration ranging from 0.516 (Mn) to 2061 (K) mug/g. Muscles samples presented the elements K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Br and Sr at concentrations ranging from 0.043 (Ni) to 1917 (K) mug/g. Potassium (K), Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Sn, Ce, and Pb were the elements detected in the sediment samples with concentration between 3.8 (Cu) and 14628 (Fe)mug/g. (author)

  13. A simple method for the multi-elemental analysis of organic fertilizer by slurry sampling and total reflection X-ray fluorescence.

    Science.gov (United States)

    Resende, Luciene V; Nascentes, Clésia C

    2016-01-15

    A simple and fast method for the multi-elemental determination of 18 inorganic constituents (P, S, Cl, K, Ca, Ti, Cr, V, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Ba and Pb) in organic fertilizers employing slurry sampling and total reflection X-ray fluorescence (TXRF) is presented. A 2(3) factorial design with a central point was employed to optimize the slurry sampling procedure. The internal standard and instrumental conditions were optimized by univariate studies. The selectivity of the method to determining Se, As, Pb, Cr, Ni and Cd was assessed. The accuracy was evaluated by the analysis of four standard reference materials (SRM). The recoveries varied from 72% to 114%. For most of the elements, good agreement was achieved between the certified value and the value measured in the SRM. The relative standard deviation (RSD %) ranged from 0.5% to 14%. The evaluated method was applied to the determination of analytes in the press cake of palm, castor, curcas, sunflower, fodder turnip, white lupin, rapeseed and pequi, and their potential to be used as organic fertilizer was evaluated in accordance with Brazilian legislation. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. 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.

  15. Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Cristina, E-mail: vazquez@cnea.gov.a [Universidad de Buenos Aires, Facultad de Ingenieria, Paseo Colon 850. C1063ACU, Buenos Aires (Argentina); Comision Nacional de Energia Atomica, Gerencia Quimica, Av. Gral Paz 1499, B1650KNA, San Martin (Argentina); Custo, Graciela, E-mail: custo@cnea.gov.a [Comision Nacional de Energia Atomica, Gerencia Quimica, Av. Gral Paz 1499, B1650KNA, San Martin (Argentina); Barrio, Nestor, E-mail: nbarrio@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina); Burucua, Jose, E-mail: gburucua@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina); Boeykens, Susana [Universidad de Buenos Aires, Facultad de Ingenieria, Paseo Colon 850. C1063ACU, Buenos Aires (Argentina); Marte, Fernando, E-mail: fmarte@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina)

    2010-09-15

    This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Produccion e Investigacion en Restauracion y Conservacion Artistica y Bibliografica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro Gonzalez Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro Gonzalez Telmo Sibyls may have been painted.

  16. Total reflection X-ray fluorescence applied to the chemical elements analysis of the mate tea infusion (Ilex-paraguariensis)

    International Nuclear Information System (INIS)

    Lopes, Fabio; Appoloni, Carlos R.; Cunha, Richard M. da Silva e; Nascimento Filho, Virgilio Franco do

    2002-01-01

    The purpose was to evaluate simultaneously the chemical element concentrations from K to Sr (19≤Z≤38) range in six samples of mate tea (Ilex paraguariensis) infusion, commercially available in Paraguay and South of Brazil. The chemical analysis of this beverage has a great nutritional importance for the native people of these areas, due to their large daily consumption. For the determination of these elements the dry-ashing and total reflection X-rays fluorescence (TXRF) were used. The methodology showed limits of detection among 81 ng.mL-1 for K to 10 ng.mL -1 for Zn. Six infusion samples were prepared in triplicate, and the concentration was 3,8 to 10,2 μg.mL -1 for K, Ca and Mn, 0,21 to 1,07 μg. mL -1 for Fe and Zn and 0.03 to 0,17 μg.mL -1 for Ni, Cu, Br, Rb and Sr. The Mn and Ni concentrations are above the maximum permissible values for drinking water established by World Health Organization and Brazilian legislation (these organisms do not regulate the maximum permissible values for chemical elements in mate tea infusion). (author)

  17. 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.

  18. Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

    Science.gov (United States)

    Vázquez, Cristina; Custo, Graciela; Barrio, Néstor; Burucúa, José; Boeykens, Susana; Marte, Fernando

    2010-09-01

    This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Producción e Investigación en Restauración y Conservación Artística y Bibliográfica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro González Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro González Telmo Sibyls may have been painted.

  19. Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Custo, Graciela; Barrio, Nestor; Burucua, Jose; Boeykens, Susana; Marte, Fernando

    2010-01-01

    This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Produccion e Investigacion en Restauracion y Conservacion Artistica y Bibliografica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro Gonzalez Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro Gonzalez Telmo Sibyls may have been painted.

  20. The use of total reflectance X-ray fluorescence (TXRF) for the determination of metals in the pharmaceutical industry.

    Science.gov (United States)

    Antosz, Frederick J; Xiang, Yanqiao; Diaz, Angel R; Jensen, Andrew J

    2012-03-25

    The control of residual metals in active pharmaceutical ingredients (API's) and intermediates is critical because of their potential toxic effects. A variety of technologies are available to measure residual metals in pharmaceutical compounds including, AAS, ICP-AES, and ICP-MS. The newest technology is total reflectance X-ray fluorescence spectroscopy (TXRF) which uses primary X-rays to excite atoms which then emit secondary X-rays. The emitted X-rays are characteristic of the individual elements present, and the intensities of the emitted X-rays are proportional to the concentrations of the elements present in the sample. The benefits of TXRF are that it is essentially unaffected by matrix effects, is very sensitive (ppb's), requires small amounts of sample (5-10 mg), and requires very little sample preparation time. During this study, TXRF was used to quantitatively measure residual metals in API's and intermediates and such topics as sample preparation, sensitivity, linearity, reproducibility and accuracy are discussed. The results obtained by TXRF were compared with those obtained by ICP-MS for the same samples for Pd and Cu measurement, and statistical analysis indicated that the results obtained by the two technologies are equivalent at the 95% confidence level. A comparison is also made of the capabilities of the instruments using a tungsten (W) or a molybdenum (Mo) source for excitation. Both instruments could be used for the quantitative determination of residual metals in pharmaceuticals. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Trace elemental analysis of drugs of abuse using synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF).

    Science.gov (United States)

    Muratsu, Seiji; Ninomiya, Toshio; Kagoshima, Yasushi; Matsui, Junji

    2002-09-01

    Synchrotron radiation total reflection X-ray fluorescence spectroscopy (SR-TXRF) was utilized to analyze various trace elements in small amounts of drugs of abuse. Sample amounts of 1 microL solutions containing 10 microg of drugs (methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine, cocaine, and heroin) were spotted on silicon wafers for direct analysis. In addition, a leaflet of marijuana was set directly on a silicon wafer, and opium in the form of a soft lump was smeared on another silicon wafer for analysis. In these experiments, about 10 pg of contaminant elements could be detected. For example, in a seized methamphetamine sample, iodine was found, which could be indicative of synthetic route. In seized 3,4-methylenedioxymethamphetamine samples, variable amounts of phosphorus, calcium, sulfur, and potassium were found, which could not be detected in a control 3,4-methylenedioxymethamphetamine sample. For marijuana and opium, two spectral patterns were obtained that were far different from each other and could be easily discriminated. Using SR-TXRF, pg amounts of each trace element in 10 microg of various drugs can be easily detected, which is not the case either for a standard TXRF experimental system or for other elemental analysis techniques.

  2. Analytical performance of benchtop total reflection X-ray fluorescence instrumentation for multielemental analysis of wine samples

    Science.gov (United States)

    Dalipi, Rogerta; Marguí, Eva; Borgese, Laura; Bilo, Fabjola; Depero, Laura E.

    2016-06-01

    Recent technological improvements have led to a widespread adoption of benchtop total reflection X-ray fluorescence systems (TXRF) for analysis of liquid samples. However, benchtop TXRF systems usually present limited sensitivity compared with high-scale instrumentation which can restrict its application in some fields. The aim of the present work was to evaluate and compare the analytical capabilities of two TXRF systems, equipped with low power Mo and W target X-ray tubes, for multielemental analysis of wine samples. Using the Mo-TXRF system, the detection limits for most elements were one order of magnitude lower than those attained using the W-TXRF system. For the detection of high Z elements like Cd and Ag, however, W-TXRF remains a very good option due to the possibility of K-Lines detection. Accuracy and precision of the obtained results have been evaluated analyzing spiked real wine samples and comparing the TXRF results with those obtained by inductively coupled plasma emission spectroscopy (ICP-OES). In general, good agreement was obtained between ICP-OES and TXRF results for the analysis of both red and white wine samples except for light elements (i.e., K) which TXRF concentrations were underestimated. However, a further achievement of analytical quality of TXRF results can be achieved if wine analysis is performed after dilution of the sample with de-ionized water.

  3. Intelligent simultaneous quantitative online analysis of environmental trace heavy metals with total-reflection X-ray fluorescence.

    Science.gov (United States)

    Ma, Junjie; Wang, Yeyao; Yang, Qi; Liu, Yubing; Shi, Ping

    2015-05-06

    Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

  4. Intelligent Simultaneous Quantitative Online Analysis of Environmental Trace Heavy Metals with Total-Reflection X-Ray Fluorescence

    Directory of Open Access Journals (Sweden)

    Junjie Ma

    2015-05-01

    Full Text Available Total-reflection X-ray fluorescence (TXRF has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

  5. Analytical capabilities of total reflection X-ray fluorescence spectrometry for silver nanoparticles determination in soil adsorption studies

    Science.gov (United States)

    Torrent, Laura; Iglesias, Mònica; Hidalgo, Manuela; Marguí, Eva

    2016-12-01

    In recent years, the production of silver nanoparticles (AgNPs) has grown due to their antibacterial properties. This fact enhances the release of these particles into the environment, especially in soils that are the major sink. To better understand adsorption processes in soils, usually batch kinetic studies are carried out. In this context, we tested the possibilities of using total reflection X-ray fluorescence spectrometry (TXRF) to monitor the silver content in soil adsorption kinetic studies. It was found that the lower limit of detection for Ag (through Ag-Kα detection) in aqueous solutions was around 37 μg·L- 1, which was suitable to carry out this kind of studies. Moreover, the direct analysis of Ag adsorbed onto soil after the kinetic studies was investigated. In this case, the limit of detection for Ag was around 1.7 mg·kg- 1. All TXRF results were compared with those obtained by inductively coupled plasma optic emission spectrometry and good agreement was found. The batch adsorption tests performed showed that 98% of polyvinylpyrrolidone coated AgNPs were retained on the tested soils in < 6 h.

  6. Elemental analysis of tree leaves by total reflection X-ray fluorescence: New approaches for air quality monitoring.

    Science.gov (United States)

    Bilo, Fabjola; Borgese, Laura; Dalipi, Rogerta; Zacco, Annalisa; Federici, Stefania; Masperi, Matteo; Leonesio, Paolo; Bontempi, Elza; Depero, Laura E

    2017-07-01

    This work shows that total reflection X-ray fluorescence (TXRF) is a fast, easy and successful tool to determine the presence of potentially toxic elements in atmospheric aerosols precipitations on tree leaves. Leaves are collected in eleven parks of different geographical areas of the Brescia city, Northern Italy, for environmental monitoring purposes. Two sample preparation procedures are considered: microwave acid digestion and the novel SMART STORE method for direct analysis. The latter consists in sandwiching a portion of the leaf between two organic foils, metals free, to save it from contamination and material loss. Mass composition of macro, micro and trace elements is calculated for digested samples, while relative elemental amount are obtained from direct analysis. Washed and unwashed leaves have a different composition in terms of trace elements. Differentiation occurs according to Fe, Pb and Cu contributions, considered as most representative of air depositions, and probably related to anthropogenic sources. Direct analysis is more representative of the composition of air precipitations. Advantages and drawbacks of the presented methods of sample preparation and TXRF analysis are discussed. Results demonstrate that TXRF allows to perform accurate and precise quantitative analysis of digested samples. In addition, direct analysis of leaves may be used as a fast and simple method for screening in the nanograms range. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Worldwide distribution of Total Reflection X-ray Fluorescence instrumentation and its different fields of application: A survey

    Energy Technology Data Exchange (ETDEWEB)

    Klockenkämper, Reinhold, E-mail: reinhold.klockenkaemper@isas.de; Bohlen, Alex von

    2014-09-01

    A survey was carried out with users and manufacturers of Total Reflection X-ray Fluorescence instrumentation in order to demonstrate the worldwide distribution of TXRF equipment and the different fields of applications. In general, TXRF users come from universities and scientific institutes, from working places at synchrotron beam-lines, or laboratories in semiconductor fabs. TXRF instrumentation is distributed in more than 50 countries on six continents and is applied at about 200 institutes and laboratories. The number of running desktop instruments amounts to nearly 300 units. About 60 beamlines run working places dedicated to TXRF. About 300 floor-mounted instruments are estimated to be used in about 150 fabs of the semiconductor industry. In total, 13 different fields of applications could be registered statistically from three different aspects. - Highlights: • According to the survey world maps show the distribution of TXRF equipment. • Nearly 700 individual units are running actually in 57 countries of 6 continents. • Users work at 200 universities, 60 synchrotron-beamlines, and 150 semiconductor fabs. • 13 fields of applications (e.g. environmental, chemical) are evaluated statistically. • Manufacturers, conference members and authors lead to 3 different pie-charts.

  8. Determination of trace perchlorate concentrations by anion-selective membranes and total reflection X-ray fluorescence analysis.

    Science.gov (United States)

    Hatzistavros, Vasilios S; Kallithrakas-Kontos, Nikolaos G

    2011-05-01

    In the present work a method for the determination of perchlorate trace levels by total reflection X-ray fluorescence (TXRF) is introduced. Perchlorate anions were concentrated on anion-selective membranes that had been prepared on the surface of TXRF quartz reflectors. Various complexation substances were used in the membranes. The reflectors were immersed in water solutions containing nanogram per milliliter (ppb) concentrations of perchlorate. After this step, the reflectors were taken out of the solution and they were analyzed by TXRF, using a copper X-ray tube and helium flow on the target (to lower the argon peak which is present in the air). The effects of various experimental parameters were examined, and the possibility of discrimination between chloride and perchlorate anions was shown. Minimum detection limits lower than 1 ng/mL and good linearity at the concentration range of 1-50 ng/mL were achieved. The method is applicable for the analysis of perchlorate in drinking water samples.

  9. Analysis of inlet and outlet industrial wastewater effluents by means of benchtop total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Marguí, E; Tapias, J C; Casas, A; Hidalgo, M; Queralt, I

    2010-06-01

    The monitoring of heavy metals in industrial waste water effluents is an important activity in many laboratories. Of special interest is the screening of elemental composition of inlet effluents and quantitative analysis of outlet effluents to study the efficiency of chemical treatment process to eliminate metals and to comply with current established concentration limits, respectively. In this sense, fast analytical methodologies which entail simple sample preparation are desired. In the present work, the possibilities and drawbacks of a benchtop total reflection X-ray fluorescence spectrometer (TXRF) for the rapid and simple determination of some inorganic impurities (As, Ba, Cd, Cu, Cr, Sn, Fe, Mn, Ni, Pb, Se and Zn) in inlet and outlet industrial waste water effluents from metallurgical and tanning leather factories have been tested. An evaluation of different simple sample treatments is presented and it is followed by a discussion of spectral and chemical matrix effects when dealing with this type of samples. Analytical figures of merit such as accuracy, precision and limits of detection have also been carefully studied. Finally, the data obtained by direct TXRF analysis has been compared to that obtained by ICP-OES/ICP-MS after a microwave digestion. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  10. Trapping of microwave radiation in hollow polypyrrole microsphere through enhanced internal reflection: A novel approach

    Science.gov (United States)

    Panigrahi, Ritwik; Srivastava, Suneel K.

    2015-01-01

    In present work, spherical core (polystyrene, PS)/shell (polypyrrole, PPy) has been synthesized via in situ chemical oxidative copolymerization of pyrrole (Py) on the surface of sulfonated PS microsphere followed by the formation of hollow polypyrrole (HPPy) shell by dissolving PS inner core in THF. Thereafter, we first time established that such fabricated novel art of morphology acts as a conducting trap in absorbing electromagnetic (EM) wave by internal reflection. Further studies have been extended on the formation of its silver nanocomposites HPPy/Ag to strengthen our contention on this novel approach. Our investigations showed that electromagnetic interference (EMI) shielding efficiency (SE) of HPPy (34.5-6 dB) is significantly higher compared to PPy (20-5 dB) in the frequency range of 0.5-8 GHz due to the trapping of EM wave by internal reflection. We also observed that EMI shielding is further enhanced to 59-23 in 10 wt% Ag loaded HPPy/Ag-10. This is attributed to the simultaneous contribution of internal reflection as well as reflection from outer surface. Such high EMI shielding capacity using conducting polymers are rarely reported.

  11. International education and reflection: transition of Swedish and American nursing students to authenticity.

    Science.gov (United States)

    Lepp, Margret; Zorn, CeCelia R; Duffy, Patricia R; Dickson, Rana J

    2003-01-01

    Reflection, a process grounded in distancing from the self to enhance self-awareness, can be used as a pedagogic activity to promote students' transition to a greater authenticity and professionalism and, therefore, improve patient care and nursing practice. In this international educational project (implemented in 2001) using interactive videoconferencing technology (IVC), Swedish and U.S. nursing students and faculty incorporated reflective journaling, drama in education, photolanguage, and off-air meeting discussions to enhance personal and professional development. Highlights from the literature, a description of the project, and student and faculty appraisals are presented.

  12. Total Internal Reflection Accounts for the Bright Color of the Saharan Silver Ant

    Science.gov (United States)

    Aron, Serge

    2016-01-01

    The Saharan silver ant Cataglyphis bombycina is one of the terrestrial living organisms best adapted to tolerate high temperatures. It has recently been shown that the hairs covering the ant’s dorsal body part are responsible for its silvery appearance. The hairs have a triangular cross-section with two corrugated surfaces allowing a high optical reflection in the visible and near-infrared (NIR) range of the spectrum while maximizing heat emissivity in the mid-infrared (MIR). Those two effects account for remarkable thermoregulatory properties, enabling the ant to maintain a lower thermal steady state and to cope with the high temperature of its natural habitat. In this paper, we further investigate how geometrical optical and high reflection properties account for the bright silver color of C. bombycina. Using optical ray-tracing models and attenuated total reflection (ATR) experiments, we show that, for a large range of incidence angles, total internal reflection (TIR) conditions are satisfied on the basal face of each hair for light entering and exiting through its upper faces. The reflection properties of the hairs are further enhanced by the presence of the corrugated surface, giving them an almost total specular reflectance for most incidence angles. We also show that hairs provide an almost 10-fold increase in light reflection, and we confirm experimentally that they are responsible for a lower internal body temperature under incident sunlight. Overall, this study improves our understanding of the optical mechanisms responsible for the silver color of C. bombycina and the remarkable thermoregulatory properties of the hair coat covering the ant’s body. PMID:27073923

  13. Remote Sensing Study of the Influence of Different Herbicides on the Leaf Spectral Reflectance and Fluorescence of Pea Plants (Pisum sativum L.)

    Science.gov (United States)

    Krezhova, Dora; Yanev, Tony; Iliev, Ilko; Alexieva, Vera; Tsaneva, Mariana

    The effective use of airborne and satellite-based remote sensor systems in resource management, agriculture, mineral exploration and environmental monitoring requires an understanding of the nature and limitations of the high-resolution remote sensing data and of various strategies for processing and interpreting it. In developing the necessary knowledge base, ground-based measurements are the expedient source of information. In this study, remote sensing techniques were applied in laboratory for detection of the influence of herbicides 2.4-D, glyphosate, fluridone and acifluorfen on the leaf spectral reflectance and fluorescence of pea plants (Pisum sativum L.). According to the classification of the Herbicide Resistance Action Committee with reference to their mode of action they belong to different groups: synthetic auxins - O (2.4-D), inhibition of EPSP synthase - G (glyphosate), photobleaching - F1 (fluridone), and inhibition of PPO - E (acifluorfen). During the last 40 years, these herbicides are among the ones used most widely in agriculture worldwide. The plants studied were grown hydroponically in a growth chamber in a nutritious medium to which every herbicide was added at two low concentrations (1 µM, 0.1 µM) with respect to the field dose applied in the agricultural practice. High-resolution spectral data for leaf spectral reflectance and fluorescence were collected from freshly detached leaves using three multichannel spectrometers. Spectral reflectance characteristics were obtained from the leaf reflectance referenced against a standard (white diffuse screen) in the visible and near infrared ranges of the electromagnetic spectrum (450÷850 nm). Fluorescence spectra were taken in the spectral range 650-850 nm. To assess the changes arising in leaf spectral reflectance under the herbicide action we developed and applied an analytical approach based on discriminant analysis and other statistical methods. The spectral characteristics were analyzed in

  14. Depth enhancement of multi-layer light field display using polarization dependent internal reflection.

    Science.gov (United States)

    Jo, Na-Young; Lim, Hong-Gi; Lee, Sung-Keun; Kim, Yong-Soo; Park, Jae-Hyeung

    2013-12-02

    A technique to enhance the depth range of the multi-layer light field three-dimensional display is proposed. A set of the optical plates are stacked in front of the conventional multi-layer light field display, creating additional internal reflection for one polarization state. By switching between two orthogonal polarization states in synchronization with the displayed three-dimensional images, the depth range of the display can be doubled. The proposed method is verified experimentally, confirming its feasibility.

  15. Trapping of microwave radiation in hollow polypyrrole microsphere through enhanced internal reflection: A novel approach

    OpenAIRE

    Ritwik Panigrahi; Suneel K. Srivastava

    2015-01-01

    In present work, spherical core (polystyrene, PS)/shell (polypyrrole, PPy) has been synthesized via in situ chemical oxidative copolymerization of pyrrole (Py) on the surface of sulfonated PS microsphere followed by the formation of hollow polypyrrole (HPPy) shell by dissolving PS inner core in THF. Thereafter, we first time established that such fabricated novel art of morphology acts as a conducting trap in absorbing electromagnetic (EM) wave by internal reflection. Further studies have bee...

  16. Specific Features of Reflection of Information Regarding Lease Operations in the National and International Standards

    Directory of Open Access Journals (Sweden)

    Nikolenko Nataliya V.

    2013-12-01

    Full Text Available The article identifies the degree of correspondence of the national Provisions (Standard of Business Accounting (PSBA Lease with the international standard and provides recommendations with respect to their closing up. On the results of the study the author provides specific features of international and national standards – the existing IFRS 17 Lease and national PSBA 14 Lease by the following components: definition of lease, its classification and reflection in accounting. Also the text of PSBA 31 Financial Expenditures is supplemented with provisions on capitalisation of financial expenditures prospectively, which would allow avoidance of correction of the balance of the retained income and provision of comparative information for previous periods. The article provides an algorithm of division of lease for accounting purposes on the basis of international standards. Its use would ensure correctness of reflection of lease operations in accounting and would serve as a basis for development of methodical provisions with respect to accounting. By the result of the study the author forms definition of the qualification asset as an asset which requires considerable time for its creation, preparation for target use, sales or acquisition of the ownership right. Capitalisation of such expenditures would allow non-reduction of the accounting income and also would provide a possibility to reflect financial expenditures in accordance with their economic essence.

  17. Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Zhiliang [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Kerr, Daniel [Program in the Biophysical Sciences, Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA; Hwang, Hyeondo Luke [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Henderson, J. Michael [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Suwatthee, Tiffany [The College, The University of Chicago, Chicago, Illinois 60637, USA; Slaw, Benjamin R. [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Cao, Kathleen D. [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Lin, Binhua [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA; Bu, Wei [Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA; Lee, Ka Yee C. [James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA; Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA; Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA

    2017-03-01

    Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68+6-568-5+6 Å2 per ion, consistent with the result published for the same dataset.

  18. Determination of trace elements in freshwater rotifers and ciliates by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Woelfl, S.; Óvári, M.; Nimptsch, J.; Neu, T. R.; Mages, M.

    2016-02-01

    Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17-9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

  19. Determination of As concentration in earthworm coelomic fluid extracts by total-reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Allegretta, Ignazio; Porfido, Carlo; Panzarino, Onofrio; Fontanella, Maria Chiara; Beone, Gian Maria; Spagnuolo, Matteo; Terzano, Roberto

    2017-04-01

    Earthworms are often used as sentinel organisms to study As bioavailability in polluted soils. Arsenic in earthworms is mainly sequestrated in the coelomic fluids whose As content can therefore be used to asses As bioavalability. In this work, a method for determining As concentration in coelomic fluid extracts using total-reflection X-ray fluorescence spectrometry (TXRF) is presented. For this purpose coelomic fluid extracts from earthworms living in three polluted soils and one non-polluted (control) soil have been collected and analysed. A very simple sample preparation was implemented, consisting of a dilution of the extracts with polyvinyl alcohol (PVA) using a 1:8 ratio and dropwise deposition of the sample on the reflector. A detection limit of 0.2 μg/l and quantification limit of 0.6 μg/l was obtained in the diluted samples, corresponding to 2 μg/l and 6 μg/l in the coelomic fluid extracts, respectively. This allowed to quantify As concentration in coelomic fluids extracted from earthworms living in soils polluted with As at concentrations higher than 20 mg/kg (considered as a pollution threshold for agricultural soils). The TXRF method has been validated by comparison with As concentrations in standards and by analysing the same samples by ICP-MS, after acid digestion of the sample. The low limit of detection, the proven reliability of the method and the little sample preparation make TXRF a suitable, cost-efficient and "green" technique for the analysis of As in earthworm coelomic fluid extracts for bioavailability studies.

  20. Use of total-reflection x-ray fluorescence in search of a biomonitor for environmental pollution in Vietnam

    International Nuclear Information System (INIS)

    Boman, J.; Wagner, A.; Brauer, H.; Viet Binh, D.

    2000-01-01

    The concentration of trace elements in tissues of several animals collected in the Ha Nam province, about 25 km south of Hanoi, Vietnam, has been investigated using total-reflection x-ray fluorescence (TXRF). With this study we wanted to address whether any of the animals were possible candidates for being bio-monitors for the pollution situation in a selected area of Vietnam. We also aim to compare the measured trace element concentrations to those representative to other provinces in Vietnam as well as to other parts of the world. An extensive bio-diversity of animals exists in Vietnam, where many of them play an important economic role in the agricultural breeding and production. The accumulation process of trace elements is still not known for a large number of animals. The parts of the collected animals chosen for analysis were muscle tissue and liver. The specimens were dried under vacuum and kept frozen. Before the TXRF analysis, the solid and dried samples were digested in nitric acid. The analysis was made at the Department of Physics at Chalmers University of Technology and Goeteborg University, Sweden, where a TXRF spectrometer has been developed by the Environmental Physics group. The results show that there could be a large variation in the concentration of trace elements, not only between the different animals but also between tissue parts of the same animal. Obviously, when selecting an organism to be used as a bio-monitor, other factors than the mere concentration of trace elements must be considered. (author)

  1. A simple method for the multi-elemental analysis of beer using total reflection X-ray fluorescence.

    Science.gov (United States)

    Gama, Ednilton M; Nascentes, Clésia C; Matos, Roberta P; Rodrigues, Gabrielle de C; Rodrigues, Guilherme D

    2017-11-01

    A method of direct analysis for quantification of 15 inorganic elements (P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Br, As, Rb, Sr and Pb) in beers by Total Reflection X-Ray Fluorescence (TXRF) was developed. The experimental conditions were optimized. Direct analysis was compared with the acid digestion procedure to evaluate the effect matrix and the results were satisfactory. The evaluation of the accuracy and precision was realized by analysis of two certified reference materials of natural and waste water. For the majority of the elements, good agreement was achieved between the certified value and the value measured in the CRM´s. Low detection limits were obtained and it was adequate to determine trace elements in beers and to quality control Pb and As, whose maximum limits are 200 and 100µgL -1 , respectively. The relative standard deviation (RSD%) ranged from 2.4% to 10%. The method was applied to 30 beer samples collected in several regions of Brazil. The concentration ranges (mgL -1 ) for the studied analytes were: P: (37.40-140.85); S (10.32-50.73); Cl (82.74-281.7); K (183.8-418.5); Ca (9.82-96.0); Mn (0.06-1.42); Fe (0.07-1.57); Ni (beer samples showed As and Pb concentrations above the levels established by Brazilian legislation. The developed method is simple, fast, consumes low amounts of reagents and allows the determination of a large number of analytes simultaneously. TXRF proved to be attractive and useful for routine analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Application of CO2 Snow Jet Cleaning in Conjunction with Laboratory Based Total Reflection X-Ray Fluorescence

    Science.gov (United States)

    Schmeling, M.; Burnett, D. S.; Allton, J. H.; Rodriquez, M.; Tripa, C. E.; Veryovkin, I. V.

    2013-01-01

    The Genesis mission was the first mission returning solar material to Earth since the Apollo program [1,2]. Unfortunately the return of the space craft on September 8, 2004 resulted in a crash landing, which shattered the samples into small fragments and exposed them to desert soil and other debris. Thus only small fragments of the original collectors are available, each having different degrees of surface contamination. Thorough surface cleaning is required to allow for subsequent analysis of solar wind material embedded within. An initial cleaning procedure was developed in coordination with Johnson Space Center which focused on removing larger sized particulates and a thin film organic contamination acquired during collection in space [3]. However, many of the samples have additional residues and more rigorous and/or innovative cleaning steps might be necessary. These cleaning steps must affect only the surface to avoid leaching and re-distribution of solar wind material from the bulk of the collectors. To aid in development and identification of the most appropriate cleaning procedures each sample has to be thoroughly inspected before and after each cleaning step. Laboratory based total reflection X-ray fluorescence (TXRF) spectrometry lends itself to this task as it is a non-destructive and surface sensitive analytical method permitting analysis of elements from aluminum onward present at and near the surface of a flat substrate [4]. The suitability of TXRF has been demonstrated for several Genesis solar wind samples before and after various cleaning methods including acid treatment, gas cluster ion beam, and CO2 snow jet [5 - 7]. The latter one is non-invasive and did show some promise on one sample [5]. To investigate the feasibility of CO2 snow jet cleaning further, several flown Genesis samples were selected to be characterized before and after CO2 snow application with sample 61052 being discussed below.

  3. Analytical approaches for Hg determination in wastewater samples by means of total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Marguí, E; Kregsamer, P; Hidalgo, M; Tapias, J; Queralt, I; Streli, C

    2010-07-15

    At present, there is a considerable interest in Hg monitoring in wastewater samples due to its widespread occurrence and the high toxicity of most of its compounds. Hg determination in water samples by means of total reflection X-ray fluorescence spectrometry (TXRF) entails some difficulties due to the high vapor pressure and low boiling point of this element that produce evaporation and loss of Hg from the surface of the reflector during the drying process, commonly used for sample preparation in TXRF analysis. The main goal of the present research was to develop a fast and simple chemical strategy to avoid Hg volatilization during the analysis of wastewater samples by TXRF spectrometry. Three different analytical procedures were tested for this purpose: (i) increasing the viscosity of the wastewater sample by adding a non-ionic surfactant (Triton X-114), (ii) Hg immobilization on the quartz reflectors using the extractant tri-isobutylphosphine (Cyanex 471X) and (iii) formation of a stable and non-volatile Hg complex into the wastewater sample. The best analytical strategy was found to be the formation of a Hg complex with thiourea (pH=10) before the deposition of 10 microL of sample on the reflector for following TXRF analysis. Analytical figures of merit such as linearity, limits of detection, accuracy and precision were carefully evaluated. Finally, the developed methodology was applied for the determination of Hg in different types of wastewater samples (industrial effluents, municipal effluents from conventional systems and municipal effluents from constructed wetlands). Copyright 2010 Elsevier B.V. All rights reserved.

  4. Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay

    Science.gov (United States)

    Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke; Henderson, J. Michael; Suwatthee, Tiffany; Slaw, Benjamin R.; Cao, Kathleen D.; Lin, Binhua; Bu, Wei; Lee, Ka Yee C.

    2017-03-01

    Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68-5+6 Å2 per ion, consistent with the result published for the same dataset.

  5. Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay.

    Science.gov (United States)

    Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke; Henderson, J Michael; Suwatthee, Tiffany; Slaw, Benjamin R; Cao, Kathleen D; Lin, Binhua; Bu, Wei; Lee, Ka Yee C

    2017-03-01

    Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca 2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl 2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm 2 of interfacial area contains 2.38 ± 0.06 Ca 2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca 2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr 2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr 2+ at 68 -5 +6 Å 2 per ion, consistent with the result published for the same dataset.

  6. Analysis of copper concentration in human serum by application of total reflection X-ray fluorescence method.

    Science.gov (United States)

    Kubala-Kukuś, Aldona; Banaś, Dariusz; Braziewicz, Janusz; Majewska, Urszula; Pajek, Marek; Wudarczyk-Moćko, Jolanta; Antczak, Grażyna; Borkowska, Beata; Góźdź, Stanisław; Smok-Kalwat, Jolanta

    2014-04-01

    The chemotherapy and photon radiotherapy are the most often applied methods in treatment of the cancer diseases because of their effectiveness and high cure rates. Apart from eligible destruction of the tumour, one of the side effects of these treatment methods is possible modification of main and trace element concentration in different human tissues and fluids. In this paper, the copper (Cu) level in human serum was determined by total reflection X-ray fluorescence method in 142 chemotherapy patients and in 44 healthy persons being a control group. The Cu concentration in the chemotherapy group was found to be on the level 1.78 ± 0.909 mg/L, while in the control group, it was 1.08 ± 0.551 mg/L. Performed measurements allowed for calculation of the parameters of copper concentration distribution (mean value, standard deviation, median) for both analysed groups. The theoretical nature of the concentration distribution was tested and found as a log-normal distribution (control group) and a log-stable distribution (chemotherapy group). The copper concentration distributions for both studied group were statistically compared using Kolmogorov-Smirnov test, and the conclusion was that the distributions are statistically different. Serum Cu levels were significantly higher in the chemotherapy group than in the control group. Taking into account the results for the control group, the copper concentration reference quantile ranges in human serum were obtained. The values of the mean, median and other quantiles determined in this case can be applied in two-group comparison studies. The obtained results can be used as a diagnostic tool for chemotherapy patients.

  7. Structure, characteristics and potential of commercial equipment Total Reflection X Ray Fluorescence for multielemental chemical analysis: Current State

    International Nuclear Information System (INIS)

    Ayala Jimenez, Rony E.

    1999-01-01

    The method Total Reflection X-Ray Fluorescence for chemical multielemental analysis has evolved in the last years with the availability of commercial systems for applications in the field of electronics and chemical multielemental analysis in samples of mineral and biological origin. The basic components of these equipment cam be summarized in a system of excitement, a geometric arrangement (optics) for collimate and monochromatize the primary radiation, a X-rays detector, and the electronic si stem for spectral data acquisition including the software for spectra unfolding, qualitative and quantitative analysis, and the complete instrument operation. Additionally the makers offer the conventional 45 degrees geometry for the excitement solid and liquid samples of bigger volume in direct form. The available bibliographical and commercial information to the moment of preparing this lecture, basically reports the following types of components for the X-rays spectrometers in geometry of total reflection chemical multielemental analysis (they are excluded those RTFX equipment dedicated to the electronic industry for quality control of Si wafers purity used for the production of circuits (chips). Excitation: X-rays tube of high vacuum with power among 1300 to 2000 watts and different types of anode; X-rays ceramic metal tube, with power up to 40 watts, and anode of molybdenum, tug steno, etc. Detection: detector semiconductor of silicon-lithium cooled with liquid nitrogen; detector of solid state silicon cooled electrically (Si-PI N diode or detector of diffused silicon Sdd). Optics: multi stratum monochromator; multi stratum Ni-C monochromator; double multi stratum monochromator. Electronic: spectroscopical amplifier espectroscopico and ana logical digital convertor adapted to a personal computer IBM compatible, with software for qualitative and quantitative analysis of samples by means of Windows, and for the complete operation of the analyzer from the Pc. In this work

  8. A setup for synchrotron-radiation-induced total reflection X-ray fluorescence and X-ray absorption near-edge structure recently commissioned at BESSY II BAMline.

    Science.gov (United States)

    Fittschen, U; Guilherme, A; Böttger, S; Rosenberg, D; Menzel, M; Jansen, W; Busker, M; Gotlib, Z P; Radtke, M; Riesemeier, H; Wobrauschek, P; Streli, C

    2016-05-01

    An automatic sample changer chamber for total reflection X-ray fluorescence (TXRF) and X-ray absorption near-edge structure (XANES) analysis in TXRF geometry was successfully set up at the BAMline at BESSY II. TXRF and TXRF-XANES are valuable tools for elemental determination and speciation, especially where sample amounts are limited (TXRF requires a well defined geometry regarding the reflecting surface of a sample carrier and the synchrotron beam. The newly installed chamber allows for reliable sample positioning, remote sample changing and evacuation of the fluorescence beam path. The chamber was successfully used showing accurate determination of elemental amounts in the certified reference material NIST water 1640. Low limits of detection of less than 100 fg absolute (10 pg ml(-1)) for Ni were found. TXRF-XANES on different Re species was applied. An unknown species of Re was found to be Re in the +7 oxidation state.

  9. Beyond ‘Innocents Abroad’: Reflecting on Sustainability Issues During International Study Trips

    Directory of Open Access Journals (Sweden)

    Anne H. Reilly

    2016-12-01

    Full Text Available With ecosystems and populations in many regions threatened by rapid development, sustainability is a critical component for businesses in mature markets and emerging economies alike. The International Association of Jesuit Business Schools notes that global sustainability involves a broad set of interconnected issues ranging from environmental preservation to social justice to desirable production and consumption patterns. Jesuit business schools are uniquely positioned to address sustainability issues with their focus on teaching managerial content in tandem with corporate social responsibility. Further, the Ignatian Pedagogy Paradigm of experience, reflection, and action would suggest that business students may benefit from reflective observation in support of learning about sustainability. In this paper, we examine the international study trip as an opportunity for students to learn about sustainability, with results suggesting that student understanding about the broad sustainability domain may be enhanced through the study abroad experience. We discuss how two classes of primarily American MBA students traveling to emerging markets (one class to Santiago, Chile and one class to Johannesburg, South Africa were able to connect local business practices with economic and social as well as environmental sustainability issues, enhancing both student engagement and learning outcomes. Further, these students’ sustainability experiences while in an unfamiliar environment provided the opportunity to apply the potentially transformative experience, reflection, and action components of the Ignatian Pedagogy Paradigm. Compared to similar graduate business students enrolled in regular classes, we argue that these students discerned deeper connections with the economic, social, and environmental issues of sustainability.

  10. Internal-wave reflection from uniform slopes: higher harmonics and Coriolis effects

    Directory of Open Access Journals (Sweden)

    T. Gerkema

    2006-01-01

    Full Text Available Weakly nonlinear reflection of internal waves from uniform slopes produces higher harmonics and mean fields; the expressions are here derived for constant stratification and with Coriolis effects fully included, i.e. the horizontal component of the earth rotation vector (referred to as 'non-traditional'' is taken into account. Uniformity in one of the horizontal directions is assumed. It is shown that solutions can be as readily derived with as without ; hence there is no need to make the so-called Traditional Approximation. Examples of reflecting internal-wave beams are presented for super-inertial, inertial and sub-inertial frequencies. The problem of resonant and non-resonant forcing of the second harmonic is studied for single plane waves; unlike under the Traditional Approximation, the problem of reflection from a horizontal bottom no longer forms a singular case. Non-traditional effects are favourable to resonant forcing at near-tidal rather than near-inertial frequencies, and generally increase the intensity of the second harmonic. Strong stratification tends to suppress non-traditional effects, but a near-total suppression is only attained for high values of stratification that are characteristic of the seasonal thermocline; in most parts of the ocean, non-traditional effects can therefore be expected to be important.

  11. A dilute-and-shoot sample preparation strategy for new and used lubricating oils for Ca, P, S and Zn determination by total reflection X-ray fluorescence

    Science.gov (United States)

    Mota, Mariana F. B.; Gama, Ednilton M.; Rodrigues, Gabrielle de C.; Rodrigues, Guilherme D.; Nascentes, Clésia C.; Costa, Letícia M.

    2018-01-01

    In this work, a dilute-and-shoot method was developed for Ca, P, S and Zn determination in new and used lubricating oil samples by total reflection X-ray fluorescence (TXRF). The oil samples were diluted with organic solvents followed by addition of yttrium as internal standard and the TXRF measurements were performed after solvent evaporation. The method was optimized using an interlaboratorial reference material. The experimental parameters evaluated were sample volume (50 or 100 μL), measurement time (250 or 500 s) and volume deposited on the quartz glass sample carrier (5 or 10 μL). All of them were evaluated and optimized using xylene, kerosene and hexane. Analytical figures of merit (accuracy, precision, limit of detection and quantification) were used to evaluate the performance of the analytical method for all solvents. The recovery rates varied from 99 to 111% and the relative standard deviation remained between 1.7% and 10% (n = 8). For all elements, the results obtained by applying the new method were in agreement with the certified value. After the validation step, the method was applied for Ca, P, S and Zn quantification in eight new and four used lubricating oil samples, for all solvents. The concentration of the elements in the samples varied in the ranges of 1620-3711 mg L- 1 for Ca, 704-1277 mg L- 1 for P, 2027-9147 mg L- 1 for S, and 898-1593 mg L- 1 for Zn. The association of TXRF with a dilute-and-shoot sample preparation strategy was efficient for Ca, P, S and Zn determination in lubricating oils, presenting accurate results. Additionally, the time required for analysis is short, the reagent volumes are low minimizing waste generation, and the technique does not require calibration curves.

  12. Concentrators using fluorescent substances

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, M.; Tsukamoto, M. (Hitachi Seisakusho K.K., Tokyo (Japan))

    1990-01-01

    In luminescent concentrators - plates of polymethylmethacrylate (PMMA) or other transparent material with a fluorescent compound dispersed within them - incident light is trapped and concentrated by internal reflection, and shifted to a longer wavelength, as it interacts with fluorescent particles. Experience with the use of luminescent concentrators for electricity generation in conjunction with solar cells, in solar heaters, in amplifiers for light intensity, in long-wave converters and in display panels is discussed. Solar energy conversion efficiencies of 4-5% have been obtained in generating systems combining concentrators containing Fluorol 555 or Rhodamin 6G with GaAs solar cells. (author).

  13. Total reflection x-ray fluorescence (TXRF) - a tool to obtain information about different air masses and air pollution

    International Nuclear Information System (INIS)

    Schmeling, M.

    2000-01-01

    Aerosols are solid particles dissolved in the atmosphere and have strong influence in the earth climate. Their solid surfaces are the only atmospheric medium for condensation of water leading to cloud formation and ultimately to precipitation. Besides their role in cloud formation, the elemental composition of aerosols reveals useful information about air masses and their transport patterns as well as air pollution. The elemental composition can be considered like a fingerprint of an air mass telling the story about its origin and fate. The presence of Al, Ti and Fe for instance indicates a source located in a highly exposed soil or often desert region, whereas Ni, V and Pb can be traced back to anthropogenic activities like fuel combustion or industrial processes. Other important source regions are the oceans, which emit the main aerosol constituents Na, Cl, and S. The concentrations of these elements in the atmosphere are extremely low and long sampling times are necessary to gain reliable results with most of the common analysis techniques. In contrast to this total reflection x-ray fluorescence (TXRF), as a technique capable to cope with tiny sample amounts, offers the unique possibility to reduce collection times to a minimum of minutes to hours. Such short sampling times in turn render it possible to monitor different air masses either passing through a ground based station or -in the ideal case- flown into by a small research aircraft. Different aerosol samples were taken by aircraft during the second aerosol characterization experiment (ACE-2) with sampling times ranging from 15 minutes up to one hour. These filter samples were analyzed by TXRF for trace elements subsequently. Together with background information about back trajectories and size distribution covering the time of sampling the presence of different air masses could be detected. In another project, short-term samples in the Chicago/Lake Michigan area are collected to study the air mass

  14. A rapid total reflection X-ray fluorescence protocol for micro analyses of ion profiles in Arabidopsis thaliana

    Science.gov (United States)

    Höhner, Ricarda; Tabatabaei, Samaneh; Kunz, Hans-Henning; Fittschen, Ursula

    2016-11-01

    The ion homeostasis of macro and micronutrients in plant cells and tissues is a fundamental requirement for vital biochemical pathways including photosynthesis. In nature, ion homeostasis is affected mainly by three processes: 1. Environmental stress factors, 2. Developmental effects, and 3. Loss or gain-of-function mutations in the plant genome. Here we present a rapid total reflection X-ray fluorescence (TXRF) protocol that allows for simultaneous quantification of several elements such as potassium (K), calcium (Ca), sulfur (S), manganese (Mn) and strontium (Sr) in Arabidopsis thaliana leaf specimens. Our procedure is cost-efficient and enables precise, robust and highly reproducible measurements on tissue samples as small as 0.3 mg dry weight. As shown here, we apply the TXRF procedure to detect accurately the early replacement of K by Na ions in leaves of plants exposed to soil salinity, a globally increasing abiotic stress factor. Furthermore, we were able to prove the existence of a leaf development-dependent ion gradient for K, Ca, and other divalent ions in A. thaliana; i.e. old leaves contain significantly lower K but higher Ca than young leaves. Lastly, we show that our procedure can be readily applied to reveal subtle differences in tissue-specific ion contents of plant mutants. We employed independent A. thaliana kea1kea2 loss-of-function mutants that lack KEA1 and KEA2, two highly active chloroplast K exchange proteins. We found significantly increased K levels specifically in kea1kea2 mutants, i.e. 55 mg ∗ g- 1 dry weight, compared to 40 mg ∗ g- 1 dry weight in wild type plants. The TXRF procedure can be supplemented with Flame atomic absorption (FAAS) and emission spectrometry (FAES) to expand the detection range to sodium (Na) and magnesium (Mg). Because of the small sample amounts required, this method is especially suited to probe individual leaves in single plants or even specific leaf areas. Therefore, TXRF represents a powerful method to

  15. 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.

  16. Design rule of nanostructures in light-emitting diodes for complete elimination of total internal reflection.

    Science.gov (United States)

    Son, Jun Ho; Kim, Jong Uk; Song, Yang Hee; Kim, Buem Joon; Ryu, Chul Jong; Lee, Jong-Lam

    2012-05-02

    Cone-shaped nanostructures with controllable side-wall angle are success- fully fabricated with a SiO(2) nanosphere lithography (NSL) etching mask. Vertical LEDs with cone-shaped nanostructures with a 24.1° side-wall angle provide 6% more light output power compared to those using hexagonal pyramids formed by photochemical etching. This achievement is attributed to effective elimination of total internal reflection by angle-controlled nanostructures. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Innovative light collimator with afocal lens and total internal reflection lens for daylighting system.

    Science.gov (United States)

    Chen, Bo-Jian; Chen, Yin-Ti; Ullah, Irfan; Chou, Chun-Han; Chan, Kai-Cyuan; Lai, Yi-Lung; Lin, Chia-Ming; Chang, Cheng-Ming; Whang, Allen Jong-Woei

    2015-10-01

    This research presents a novel design of the collimator, which uses total internal reflection (TIR), convex, and concave lenses for the natural light illumination system (NLIS). The concept of the NLIS is to illuminate building interiors with natural light, which saves energy consumption. The TIR lens is used to collimate the light, and convex and concave lenses are used to converge the light to the required area. The results have shown that the efficiency in terms of achieving collimated light using the proposed collimator at the output of the light collector is better than that of a previous system without a collimator.

  18. International peer review in undergraduate dentistry: enhancing reflective practice in an online community of practice.

    Science.gov (United States)

    Gardner, K; Bridges, S; Walmsley, D

    2012-11-01

    To stimulate and enhance student learning in the areas of global citizenship, critical reflection and e-learning, an online international peer review using a purpose-built web platform, has been developed between international dental schools. Since its inception in 2007, n = 6 dental schools from six different countries have participated with n = 384 dental students engaged in online peer review. Project development was conceptually analysed utilising Lave and Wenger's notion of a community of practice (CoP). Analysis drew on the three core components within the CoP organising framework: domain, community and practice. All three components were evident in building project identity. The domain focused on both curriculum and institutional co-operation. The community was evident for both educators and students. Finally, analysis of practice was found to be significant in terms of sustained interaction and collaboration. Empirical evaluation is recommended as the next phase of project design. © 2012 John Wiley & Sons A/S.

  19. Rapid Processing of Turner Designs Model 10-Au-005 Internally Logged Fluorescence Data

    Science.gov (United States)

    Continuous recording of dye fluorescence using field fluorometers at selected sampling sites facilitates acquisition of real-time dye tracing data. The Turner Designs Model 10-AU-005 field fluorometer allows for frequent fluorescence readings, data logging, and easy downloading t...

  20. Liability for nuclear damage: an international perspective. Reflections on the revision of the Vienna Convention

    International Nuclear Information System (INIS)

    Lopuski, J.

    1993-01-01

    This book deals with deals of the complex issues of liability and compensation for nuclear damage which have been considered in the course of the work of the IAEA concerning the revision of the Vienna Convention on nuclear liability. It presents, in an orderly way, personal reflections of its author based on his experience gathered in years 1989-1992 when participating in this work. Necessarily it contains in some of its parts references to documents of the IAEA Standing Committee on Nuclear Liability; these documents because of their length could not be reproduced. Consequently these parts may not be fully intelligible for those who have not participated in or closely followed the Committee's work. The IAEA work on liability for nuclear damage was initiated in the wake of the impact made on the world's public opinion by the Chernobyl incident and its transboundary effects; issues of international state liability and full compensation have been raised. But humanitarian ideas have quickly been confronted with cold calculations of the cost of financial protection for victims and an open unwillingness of some nuclear states has been manifested. After three years of discussions no wide consensus could be reached on some basic issues, such as: relationship between international state and civil liability regimes, structure of international legislation, concept of nuclear damage, limits of compensation, role of public funds or jurisdiction. The author presents his approach to these controversial issue, trying to provide at the same time a theoretical outline for the future international legislation on nuclear liability. (author)

  1. Determination of continuous complex refractive index dispersion of biotissue based on internal reflection

    Science.gov (United States)

    Deng, Zhichao; Wang, Jin; Ye, Qing; Sun, Tengqian; Zhou, Wenyuan; Mei, Jianchun; Zhang, Chunping; Tian, Jianguo

    2016-01-01

    The complex refractive index dispersion (CRID), which contains the information on the refractive index dispersion and extinction coefficient spectra, is an important optical parameter of biotissue. However, it is hard to perform the CRID measurement on biotissues due to their high scattering property. Continuous CRID measurement based on internal reflection (CCRIDM-IR) is introduced. By using a lab-made apparatus, internal reflectance spectra of biotissue samples at multiple incident angles were detected, from which the continuous CRIDs were calculated based on the Fresnel formula. Results showed that in 400- to 750-nm range, hemoglobin solution has complicated dispersion and extinction coefficient spectra, while other biotissues have normal dispersion properties, and their extinction coefficients do not vary much with different wavelengths. The normal dispersion can be accurately described by several coefficients of dispersion equations (Cauchy equation, Cornu equation, and Conrady equation). To our knowledge, this is the first time that the continuous CRID of scattering biotissue over a continuous spectral region is measured, and we hereby have proven that CCRIDM-IR is a good method for continuous CRID research of biotissue.

  2. Smooth and rough Proteus mirabilis lipopolysaccharides studied by total internal reflection ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Gleńska-Olender, J., E-mail: joannaglenska@wp.pl [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland); Świętokrzyski Biobank, Regional Science and Technology Center, 26-060 Chęciny (Poland); Dworecki, K. [Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Sęk, S. [Department of Chemistry, University of Warsaw, 02-093 Warsaw (Poland); Kwinkowski, M.; Kaca, W. [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland)

    2013-12-02

    Total internal reflection ellipsometry (TIRE), a label-free optical detection technique for studying interactions between biomolecules, was used to examine the adsorption of various forms of lipopolysaccharides (LPSs) isolated from Proteus mirabilis S1959, R110, and R45 strains on a gold surface. The thickness of the adsorbed layers was determined by TIRE, with the average values for S1959, R110, and R45 LPS layers being 78 ± 5, 39 ± 3, and 12 ± 2 nm, respectively. The thickness of LPS layers corresponds to the presence and length of O-specific parts in P. mirabilis LPS molecules. Atomic force microscopy was used as a complementary technique for visualizing lipopolysaccharides on the surface. Force measurements seem to confirm the data obtained from TIRE experiments. - Highlights: • Proteus mirabilis lipopolysaccharides were adsorbed on the gold surface. • Thickness of adsorbed layers was determined by total internal reflection ellipsometry. • Atomic force microscopy was used to visualize lipopolysaccharide build-up on gold surface. • Time is important in the evolution of biomolecular film thickness created on gold surface.

  3. Public Diplomacy and Refugee Relations Reflections of Turkey’s Refugees Relations on the International Media

    Directory of Open Access Journals (Sweden)

    Ergün Köksoy

    2015-11-01

    Full Text Available Public diplomacy is described as a new form of relations and communications between countries and societies in the field of international relations with the process of globalisation. The subject of refugees shown among the priority issues can be solved through international cooperation and solidarity with its results affecting all countries and societies, that’s why becoming part of public diplomacy. Asylum seekers and refugee rights are guaranteed by the Universal Declaration of Human Rights and considered to be an area that the international community needs to take the roles and share responsibilities. In this aspect, it is shown as global responsibilities and part of the humanitarian sensibility of countries and societies. In one hand, asylum seekers and refugees are considered to be the subject of the problem and crisis, on the other hand, due to contributing to the human and cultural interaction between the different communities, these are specified as part of public diplomacy. This article discusses the relationship between public diplomacy and refugees relations which provides the interaction between countries and effects the prestige and perception of them. In the study, to reveal the reflections of Turkey’s Refugees Relations on the International Media, three highest-circulation newspapers (“The Guardian”, “Le Monde”, “Der Spiegel” will be choosen from three important EU countries (United Kingdom, France, Germany. These newspapers’ headlines and news content which related to Turkey and Syrian refugees are going to be analized on three-month period. As a result, Turkish public diplomacy and refugee relations and its implications on the international media in the context of Syrian refugees will be evaluated and some recommendations for the future of Turkish public diplomacy and refugee relations will be provided.

  4. The International Criminal Court. reflections for a stress test on its foundations

    Directory of Open Access Journals (Sweden)

    Mateus Kowalski

    2011-01-01

    Full Text Available The constitution of the ICC in 2002 represents the ultimate example of the evolution of international criminal justice. The Court is referred to as a paradigmatic institution of the universalist concept of International Law, which envisages an enhanced international public order and which falls within the broader framework of the dominant liberal construct that currently characterizes both International Law and International Relations. However, the criticisms of universalism, in particular as regards the impositions of global liberal institutions and regulatory standards, are also reflected on the ICC. In particular, it has been met with several essential criticisms, such as its dependence on the Security Council, suggesting political interference in a criminal court, or the fact that until now only issues pertaining to Africa have been submitted to the Court, which in turn leads to suspicion about their selectivity. These are the criticisms that undermine the foundations of the ICC.At a time when the Court has not yet concluded any trial, and when there is still some scepticism about the success of its mission, knowing what to expect from the ICC in its task of crime preventing and retribution and building peace depends largely on the strength of its theoretical foundations. It is argued that despite the seemingly solid support discourse rooted in universalism, the answers advanced by this theory are not fully satisfactory due largely to the structural weaknesses that characterise it. This article seeks to offer food for thought on the subject and starts by gauging the competence of legal universalism to support “its” ICC with regard to these issues. It then identifies the aspects that can be addressed in within a more complex context, such as critical theory, which may contribute to the development of a discourse that grants the Court greater theoretical sustainability.

  5. Do daily and seasonal trends in leaf solar induced fluorescence reflect changes in photosynthesis, growth or light exposure

    Czech Academy of Sciences Publication Activity Database

    Wyber, R.; Malenovský, Zbyněk; Ashcroft, M. B.; Osmond, C. B.; Robinson, S. A.

    2017-01-01

    Roč. 9, č. 6 (2017), č. článku 604. ISSN 2072-4292 Institutional support: RVO:67179843 Keywords : Light induced fluorescence transient * Photosynthetic active radiation * Photosynthetic yield * Pulse amplitude modulation * Remote sensing of vegetation Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.244, year: 2016

  6. Aquafluo 2007: chlorophyll fluorescence in aquatic sciences, an international conference held in Nové Hrady

    Czech Academy of Sciences Publication Activity Database

    Prášil, Ondřej; Sugget, D. J.; Cullen, J. J.; Babin, M.; Govindjee, M.

    -, - (2007), s. 1-5 ISSN 0166-8595 Institutional research plan: CEZ:AV0Z50200510 Keywords : aquafluo * chlorophyll fluorescence Subject RIV: EE - Microbiology, Virology Impact factor: 2.139, year: 2007

  7. Raman and fluorescence microscopy to study the internalization and dissolution of photosensitizer nanoparticles into living cells

    Science.gov (United States)

    Scalfi-Happ, Claudia; Steiner, Rudolf; Wittig, Rainer; Graefe, Susanna; Ryabova, Anastasia; Loschenov, Victor

    2015-07-01

    In this present study we applied Raman and fluorescence microscopy to investigate the internalisation, cellular distribution and effects on cell metabolism of photosensitizer nanoparticles for photodynamic therapy in fibroblasts and macrophages.

  8. Preferential affinity of calcium ions to charged phosphatidic acid surface from a mixed calcium/barium solution: X-ray reflectivity and fluorescence studies.

    Science.gov (United States)

    Bu, Wei; Flores, Kevin; Pleasants, Jacob; Vaknin, David

    2009-01-20

    X-ray reflectivity and fluorescence near total reflection experiments were performed to examine the affinities of divalent ions (Ca(2+) and Ba(2+)) from aqueous solution to a charged phosphatidic acid (PA) surface. A phospholipid (1,2-dimyristoyl-sn-glycero-3-phosphate, DMPA), spread as a monolayer at the air/water interface, was used to form and control the charge density at the interface. We find that, for solutions of the pure salts (i.e., CaCl(2) and BaCl(2)), the number of bound ions per DMPA at the interface is saturated at concentrations that exceed 10(-3) M. For 1:1 Ca(2+)/Ba(2+) mixed solutions, we find that the bound Ca(2+)/Ba(2+) ratio at the interface is 4:1. If the only property determining charge accumulation near PA were the ionic charges, the concentration of mixed Ca(2+)/Ba(2+) at the interface would equal that of the bulk. Our results show a clear specific affinity of PA for Ca compared to Ba. We provide some discussion on this issue as well as some implications for biological systems. Although our results indicate an excess of counterion charge with respect to the surface charge, that is, charge inversion, the analysis of both reflectivity and fluorescence do not reveal an excess of co-ions (namely, Cl(-) or I(-)).

  9. Automated solid-phase extraction for trace-metal analysis of seawater: sample preparation for total-reflection X-ray fluorescence measurements

    Science.gov (United States)

    Gerwinski, Wolfgang; Schmidt, Diether

    1998-08-01

    Solid-phase chromatography on silica gel columns can be used as a sample preparation technique for seawater, followed by total-reflection X-ray fluorescence analysis (TXRF). An automated extraction system (Zymark AutoTrace SPE Workstation) was studied for the analysis of blank solutions, seawater samples and certified reference materials. After replacing some stainless steel parts in the system, adequate blanks could be obtained to allow the analysis of seawater samples. Replicate analyses yielded low standard deviations and good recoveries for certified reference materials. Using a six-channel model and user-defined software, the time needed for a complete analytical run was about 100 min.

  10. Determination of ultra trace contaminants on silicon wafer surfaces using total-reflection X-ray fluorescence TXRF 'state-of-the-art'

    Science.gov (United States)

    Pahlke, S.; Fabry, L.; Kotz, L.; Mantler, C.; Ehmann, T.

    2001-11-01

    In a well balanced system of highly motivated, well trained personnel and automated equipment, pure reagents and bulk media, cleanrooms and integrated data management, total-reflection X-ray fluorescence (TXRF) can and must contribute to quality assurance and process stability, support and canalize creative engineering by continuous learning about materials and processes. TXRF has the advantage of controlled one-point calibration, a linear dynamic range of three orders of magnitude, high grade of automation in operation and data management, high up-time, and a simple control of data plausibility.

  11. Application of the total reflection X-ray fluorescence method to the elemental analysis of brain tumors of different types and grades of malignancy

    Science.gov (United States)

    Lankosz, M. W.; Grzelak, M.; Ostachowicz, B.; Wandzilak, A.; Szczerbowska-Boruchowska, M.; Wrobel, P.; Radwanska, E.; Adamek, D.

    2014-11-01

    The process of carcinogenesis may influence normal biochemical reactions leading to alterations in the elemental composition of the tissue. Total reflection X-ray fluorescence analysis (TXRF) was applied to the elemental analysis of different brain tumors. The following elements were present in all the neoplastic tissues analyzed: K, Ca, Fe, Cu, Zn and Rb. The results of the analysis showed that the elemental composition of a relatively small fragment of tissue represents satisfactorily the biochemical ;signature; of a cancer. On the basis of the element concentrations determined, it was possible to differentiate between some types of brain tumors.

  12. A reflecting, steepening, and breaking internal tide in a submarine canyon

    Science.gov (United States)

    Alberty, M. S.; Billheimer, S.; Hamann, M. M.; Ou, C. Y.; Tamsitt, V.; Lucas, A. J.; Alford, M. H.

    2017-08-01

    Submarine canyons are common features of the coastal ocean. Although they are known to be hotspots of turbulence that enhance diapycnal transport in their stratified waters, the dynamics of canyon mixing processes are poorly understood. Most studies of internal wave dynamics within canyons have focused on a handful of canyons with along-axis slopes less steep than semidiurnal (D2) internal wave characteristics (subcritical). Here, we present the first tidally resolving observations within a canyon with a steeply sloping axis (supercritical). A process study consisting of two 24 h shipboard stations and a profiling mooring was conducted in the La Jolla Canyon off the coast of La Jolla, CA. Baroclinic energy flux is oriented up-canyon and decreases from 182 ±18 W m-1 at the canyon mouth to 46±5 W m-1 near the head. The ratio of horizontal kinetic energy to available potential energy and the observed group speed of each mode are lower than expected for freely propagating D2 internal waves at each station, indicating partial reflection. Harmonic analysis reveals that variance is dominated by the D2 tide. Moving up-canyon, the relative importance of D2 decreases and its higher harmonics are needed to account for a majority of the observed variance, indicating steepening. Steep internal tides cause large isopycnal displacements (˜50 m in 100 m water depth) and high strain events. These events coincide with enhanced O(10-7-10-5 m2 s-3) dissipation of turbulent kinetic energy at mid-depths.

  13. Liability for nuclear damage: an international perspective. Reflections on the revision of the Vienna Convention

    Energy Technology Data Exchange (ETDEWEB)

    Lopuski, J.

    1993-12-31

    This book deals with deals of the complex issues of liability and compensation for nuclear damage which have been considered in the course of the work of the IAEA concerning the revision of the Vienna Convention on nuclear liability. It presents, in an orderly way, personal reflections of its author based on his experience gathered in years 1989-1992 when participating in this work. Necessarily it contains in some of its parts references to documents of the IAEA Standing Committee on Nuclear Liability; these documents because of their length could not be reproduced. Consequently these parts may not be fully intelligible for those who have not participated in or closely followed the Committee`s work. The IAEA work on liability for nuclear damage was initiated in the wake of the impact made on the world`s public opinion by the Chernobyl incident and its transboundary effects; issues of international state liability and full compensation have been raised. But humanitarian ideas have quickly been confronted with cold calculations of the cost of financial protection for victims and an open unwillingness of some nuclear states has been manifested. After three years of discussions no wide consensus could be reached on some basic issues, such as: relationship between international state and civil liability regimes, structure of international legislation, concept of nuclear damage, limits of compensation, role of public funds or jurisdiction. The author presents his approach to these controversial issue, trying to provide at the same time a theoretical outline for the future international legislation on nuclear liability. (author).

  14. Development of a scanning microscopy by total internal reflection coupled with thermal lens spectroscopy.

    Science.gov (United States)

    Shimosaka, Takuya; Iwamoto, Kazutoshi; Izako, Masakazu; Suzuki, Asa; Uchiyama, Katsumi; Hobo, Toshiyuki

    2004-01-01

    Non-destructive measurement of a small region on a solid/liquid interface is of great importance in physical chemistry and biochemistry, especially in the research of thin films and cell membranes. Optical methods for surface analysis with high lateral resolution are suitable methods for monitoring them. We now report a new scanning optical microscopic method to which total internal reflection coupled with a thermal lens technique was introduced. Its lateral resolution was estimated both experimentally and theoretically. To experimentally estimate the resolution, the grid patterns of thin photoresist films with well-defined lateral structures were measured. The experimental resolution was about 45 microm, which was almost same as the diameter of the excitation beam at a glass/sample interface. From this result, it was verified that this new scanning microscopy ideally worked.

  15. Benchmarking of HEU Mental Annuli Critical Assemblies with Internally Reflected Graphite Cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Xiaobo, Liu; Bess, John D.; Marshall, Margaret A.

    2016-09-01

    Three experimental configurations of critical assemblies, performed in 1963 at the Oak Ridge Critical Experiment Facility, which are assembled using three different diameter HEU annuli (15-9 inches, 15-7 inches and 13-7 inches) metal annuli with internally reflected graphite cylinder are evaluated and benchmarked. The experimental uncertainties which are 0.00055, 0.00055 and 0.00055 respectively, and biases to the detailed benchmark models which are -0.00179, -0.00189 and -0.00114 respectively, were determined, and the experimental benchmark keff results were obtained for both detailed and simplified model. The calculation results for both detailed and simplified models using MCNP6-1.0 and ENDF VII.1 agree well to the benchmark experimental results with a difference of less than 0.2%. These are acceptable benchmark experiments for inclusion in the ICSBEP Handbook.

  16. Maintaining a stationary laser footprint during angular scan in internal-reflection experiments.

    Science.gov (United States)

    Fontana, Eduardo; Cavalcanti, Gustavo Oliveira

    2013-11-10

    In internal-reflection metrology using prisms, the prism is usually mounted on a rotation/translation stage to enable adjusting angle and location of the laser footprint on the surface. If a visual inspection method is used to find the laser footprint, the task becomes impossible if invisible radiation in the near infrared is employed. In addition, it may be desirable to perform angular scan experiments with a stationary footprint on the surface during scans, or even to automatically probe specific points on an extended prism face for predetermined incidence angles. In this paper, a formulation is developed to determine the required translation along the prism face to allow maintaining the laser footprint stationary under a given rotation. A web-based app developed under the scope of this work demonstrates the applicability of the approach for silica, BK7 and SF2 glasses, in the wavelength range from 500 to 1500 nm and for an arbitrary geometry of the glass prism.

  17. Label free imaging of cell-substrate contacts by holographic total internal reflection microscopy.

    Science.gov (United States)

    Mandracchia, Biagio; Gennari, Oriella; Marchesano, Valentina; Paturzo, Melania; Ferraro, Pietro

    2017-09-01

    The study of cell adhesion contacts is pivotal to understand cell mechanics and interaction at substrates or chemical and physical stimuli. We designed and built a HoloTIR microscope for label-free quantitative phase imaging of total internal reflection. Here we show for the first time that HoloTIR is a good choice for label-free study of focal contacts and of cell/substrate interaction as its sensitivity is enhanced in comparison with standard TIR microscopy. Finally, the simplicity of implementation and relative low cost, due to the requirement of less optical components, make HoloTIR a reasonable alternative, or even an addition, to TIRF microscopy for mapping cell/substratum topography. As a proof of concept, we studied the formation of focal contacts of fibroblasts on three substrates with different levels of affinity for cell adhesion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. An internally reflecting Cherenkov detector (DIRC): Properties of the fused silica radiators

    International Nuclear Information System (INIS)

    Adam, I.; Aston, D.

    1997-11-01

    The DIRC, a new type of ring-imaging Cherenkov detector that images internally reflected Cherenkov light, is being constructed as the main hadronic particle identification component of the BABAR detector at SLAC. The device makes use of 5 meter long fused silica (colloquially called quartz) bars, which serve both as the Cherenkov radiators and as light pipes for transmitting the light to an array of photo-multiplier tubes. This paper describes a program of research and development aimed at determining whether bars that meet the stringent requirements of the DIRC can be obtained from commercial sources. The results of studies of bulk absorption of fused silica, surface finish, radiation damage and bulk inhomogeneities are discussed

  19. Common-path configuration in total internal reflection digital holography microscopy.

    Science.gov (United States)

    Calabuig, Alejandro; Matrecano, Marcella; Paturzo, Melania; Ferraro, Pietro

    2014-04-15

    Total Internal Reflection Digital Holographic Microscopy (TIRDHM) is recognized to be a powerful tool for retrieving quantitative phase images of cell-substrate interfaces, adhesions, and tissue structures close to the prism surface. In this Letter, we develop an improved TIRDHM system, taking advantage of a refractive index mismatch between the prism and the sample substrate, to allow phase-shifting DH with just a single-beam interferometric configuration. Instead of the traditional off-axis method, phase-shift method is used to retrieve amplitude and phase images in coherent light and TIR modality. Essentially, the substrate-prism interface acts like a beam splitter generating a reference beam, where the phase-shift dependence on the incident angle is exploited in this common-path configuration. With the aim to demonstrate the technique's validity, some experiments are performed to establish the advantage of this compact and simple configuration, in which the reference arm in the setup is avoided.

  20. Analysis of thin-film polymers using attenuated total internal reflection-Raman microspectroscopy.

    Science.gov (United States)

    Tran, Willie; Tisinger, Louis G; Lavalle, Luis E; Sommer, André J

    2015-01-01

    Two methods commonly employed for molecular surface analysis and thin-film analysis of microscopic areas are attenuated total reflection infrared (ATR-IR) microspectroscopy and confocal Raman microspectroscopy. In the former method, the depth of the evanescent probe beam can be controlled by the wavelength of light, the angle of incidence, or the refractive index of the internal reflection element. Because the penetration depth is proportional to the wavelength of light, one could interrogate a smaller film thickness by moving from the mid-infrared region to the visible region employing Raman spectroscopy. The investigation of ATR Raman microspectroscopy, a largely unexplored technique available to Raman microspectroscopy, was carried out. A Renishaw inVia Raman microscope was externally modified and used in conjunction with a solid immersion lens (SIL) to perform ATR Raman experiments. Thin-film polymer samples were analyzed to explore the theoretical sampling depth for experiments conducted without the SIL, with the SIL, and with the SIL using evanescent excitation. The feasibility of micro-ATR Raman was examined by collecting ATR spectra from films whose thickness measured from 200 to 60 nm. Films of these thicknesses were present on a much thicker substrate, and features from the underlying substrate did not become visible until the thin film reached a thickness of 68 nm.

  1. Unusual conversations: A reflection on the mechanics of internationally engaged public scholarship

    Directory of Open Access Journals (Sweden)

    Jonathan Damiani

    2016-09-01

    Full Text Available This article analyses the civic engagement pathways of researchers from the Asia-Pacific and the United States in an effort to see how the principles of what American  scholars consider publicly engaged research and creative practice are being enacted in research sites across the globe. The purpose of this ongoing project is to focus on finding ways of connecting American scholars with a network of higher education and research institutions that hold a commitment and passion for social responsibility and civic engagement as it impacts education, research and service for community development overseas. The narrative includes the voices and perspectives of colleagues dedicated to engaged scholarship from across the new region in which I work (the Asia-Pacific, alongside the voices of some of Imagining America’s (IA 2014 National Conference participants. These conversations serve as a critical reflection on the mechanics of doing public scholarship overseas and frame a new model of internationally engaged scholarship. Keywords: Internationally engaged public scholarship, unusual conversations

  2. Stimulus-dependent EEG activity reflects internal updating of tactile working memory in humans.

    Science.gov (United States)

    Spitzer, Bernhard; Blankenburg, Felix

    2011-05-17

    Despite recent advances in uncovering the neural signature of tactile working memory processing in animals and humans, the representation of internally modified somatosensory working memory content has not been studied so far. Here, recording EEG in human participants (n = 25) performing a modified delayed match-to-sample task allowed us to disambiguate internally driven memory processing from encoding-related delay activity. After presentation of two distinct vibrotactile frequencies to different index fingers, a visual cue indicated which of the two previous stimuli had to be maintained in working memory throughout a retention interval for subsequent frequency discrimination against a probe stimulus. During cued stimulus maintenance, α activity (8-13 Hz) over early somatosensory cortices was lateralized according to the cued tactile stimulus, even though the location of the stimuli was task irrelevant. The task-relevant memory content, in contrast, was found to be represented in right prefrontal cortex. The key finding was that the visually presented instructions triggered systematic modulations of prefrontal β-band activity (20-25 Hz), which selectively reflected the to-be-maintained frequency of the cued tactile vibration. The results expand previous evidence for parametric representations of vibrotactile frequency in the prefrontal cortex and corroborate a central role of dynamic β-band synchronization during active processing of an analog stimulus quantity in human working memory. In particular, our findings suggest that such processing supports not only sustained maintenance but also purposeful modification and updating of the task-relevant working memory contents.

  3. Special tablets containing cellulose binder and Sr internal standard for simplifying X-ray fluorescence analysis of powder samples

    Science.gov (United States)

    Mzyk, Zofia; Anyszkiewicz, Jacek; Gorewoda, Tadeusz

    2015-12-01

    The addition of a constant amount of SrCO3 was observed to be the proper internal standard for analysis by wavelength-dispersive X-ray fluorescence spectrometry to correct the matrix and grain size effects of many constituents. The weighing of constant amounts of SrCO3, binder and sample allowed for the preparation time for analysis to be extended, and special tablets containing binder and SrCO3 were developed. Several substances were tested as binders, among which microcrystalline cellulose was chosen for further study. The prepared tablets were checked for their weight stability and the repeatability of SrCO3 addition. The tablets were then used to prepare pellets from geological samples for X-ray fluorescence analysis. The exemplary application and calibration curves for several analytes confirmed that the prepared tablets could be useful for the pelletizing of such materials to compensate for matrix effects.

  4. Applicability of total reflection X-ray fluorescence (TXRF) as a screening platform for pharmaceutical inorganic impurity analysis.

    Science.gov (United States)

    Shaw, Bradley J; Semin, David J; Rider, Michael E; Beebe, Meredith R

    2012-04-07

    Palladium (Pd) is extensively used in pharmaceutical small molecule drug substance processes, however it must be removed prior to release of the active pharmaceutical ingredient (API). Evaluation of four TXRF instruments and configurations were compared to ICP-MS instrumentation for trace metal analysis, most importantly for Pd. Standards and six pharmaceutical drug substances, triprolidine HCl, diphenhydramine HCl, chlorpheniramine maleate, pseudoephedrine HCl, ephedrine sulfate, and scopolamine HBr, were analyzed to determine linearity, sensitivity, accuracy, and precision for Pd plus Cr, Fe, Cu, Rh, and Pt versus interferences, particularly from Cl, S, and Ar, on the various X-ray fluorescence lines. Irrespective of instrument platform, in general X-ray sources capable of accessing Pd-K lines were found to be most effective in determination of Pd in APIs. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Nanoliter deposition unit for pipetting droplets of small volumes for Total Reflection X-ray Fluorescence applications

    Science.gov (United States)

    Wastl, A.; Stadlbauer, F.; Prost, J.; Horntrich, C.; Kregsamer, P.; Wobrauschek, P.; Streli, C.

    2013-04-01

    A nanoliter droplet deposition unit was developed and characterized for application of sample preparation in TXRF. The droplets produced on quartz reflectors as well as on wafers show a good reproducibility, also the accuracy of the pipetted volume could be proved by a quantitative TXRF analysis using an external standard. The samples were found to be independent of rotation of the sample carrier. Angle scans showed droplet residue behavior, and the fluorescence signal is relatively invariant of the angle of incidence below the critical angle, which is useful for producing standards for external calibration for semiconductor surface contamination measurements by TXRF. Further it could be demonstrated that the nanoliter deposition unit is perfectly able to produce patterns of samples for applications like the quantification of aerosols collected by impactors.

  6. Frustrated total internal reflection in organic light-emitting diodes employing sphere cavity embedded in polystyrene

    International Nuclear Information System (INIS)

    Zhu, Peifen

    2016-01-01

    The light extraction efficiency of top-emitting organic light-emitting diodes (OLEDs) is numerically investigated employing the finite-difference time-domain method. The periodic nanostructures formed by embedding the sphere arrays in polystyrene (PS) are placed on top of OLED to frustrate the total internal reflection at the interface between OLED and free space. These nanostructures serve as an intermediate medium to extract the light out of OLED devices. Efficiently coupling both evanescent waves and propagation waves into spheres and subsequently extracting these light waves out of the sphere is key to achieving high extraction efficiency. By tuning the thickness of PS layer, both of the in-coupling efficiency and out-coupling efficiency are optimized for achieving high light extraction efficiency. Thicker PS layer results in higher in-coupling efficiency in sphere while the thinner PS layer leads to higher out-coupling efficiency. Thus the maximum light extraction is a trade-off between the in-coupling efficiency and out-coupling efficiency. The study shows that light extraction efficiency of 89% can be achieved by embedding 0.90 μm TiO 2 sphere in 0.30 μm PS layer with optimized in-coupling efficiency, out-coupling efficiency and cavity effect. (paper)

  7. Extraction of light trapped due to total internal reflection using porous high refractive index nanoparticle films.

    Science.gov (United States)

    Mao, Peng; Sun, Fangfang; Yao, Hanchao; Chen, Jing; Zhao, Bo; Xie, Bo; Han, Min; Wang, Guanghou

    2014-07-21

    TiO₂ nanoparticle layers composed of columnar TiO₂ nanoparticle piles separated with nanoscale pores were fabricated on the bottom surface of the hemispherical glass prism by performing gas phase cluster beam deposition at glancing incidence. The porosity as well as the refractive index of the nanoparticle layer was precisely tuned by the incident angle. Effective extraction of the light trapped in the substrate due to total internal reflection with the TiO₂ nanoparticle layers was demonstrated and the extraction efficiency was found to increase with the porosity. An enhanced Rayleigh scattering mechanism, which results from the columnar aggregation of the nanoparticles as well as the strong contrast in the refractive index between pores and TiO₂ nanoparticles in the nanoporous structures, was proposed. The porous TiO₂ nanoparticle coatings were fabricated on the surface of GaN LEDs to enhance their light output. A nearly 92% PL enhancement as well as a 30% EL enhancement was observed. For LED applications, the enhanced light extraction with the TiO₂ nanoparticle porous layers can be a supplement to the microscale texturing process for light extraction enhancement.

  8. Gold nanoparticle-polydimethylsiloxane films reflect light internally by optical diffraction and Mie scattering

    Science.gov (United States)

    Dunklin, Jeremy R.; Forcherio, Gregory T.; Roper, D. Keith

    2015-08-01

    Optical properties of polymer films embedded with plasmonic nanoparticles (NPs) are important in many implementations. In this work, optical extinction by polydimethylsiloxane (PDMS) films containing gold (Au) NPs was enhanced at resonance compared to AuNPs in suspensions, Beer-Lambert law, or Mie theory by internal reflection due to optical diffraction in 16 nm AuNP-PDMS films and Mie scattering in 76 nm AuNP-PDMS films. Resonant extinction per AuNP for 16 nm AuNPs with negligible resonant Mie scattering was enhanced up to 1.5-fold at interparticle separation (i.e., Wigner-Seitz radii) comparable to incident wavelength. It was attributable to diffraction through apertures formed by overlapping electric fields of adjacent, resonantly excited AuNPs at Wigner-Seitz radii equal to or less than incident wavelengths. Resonant extinction per AuNP for strongly Mie scattering 76 nm AuNPs was enhanced up to 1.3-fold at Wigner-Seitz radii four or more times greater than incident wavelength. Enhanced light trapping from diffraction and/or scattering is relevant to optoelectronic, biomedical, and catalytic activity of substrates embedded with NPs.

  9. Tunable Wide-Angle Tunneling in Graphene-Assisted Frustrated Total Internal Reflection

    Science.gov (United States)

    Tran, Thang Q.; Lee, Sangjun; Heo, Hyungjun; Kim, Sangin

    2016-01-01

    Electrically tunable permittivity of graphene provides an excellent tool in photonic device design. Many previous works on graphene-based photonic devices relied on variable absorption in graphene, which is naturally small in the optical region, and resonant structures to enhance it. Here we proposed a novel scheme to control evanescent coupling strength by inserting two graphene layers to a frustrated total internal reflection (FTIR) configuration. The resulting structure behaves in a drastically different way from the original FTIR: optical transmission though the structure can be electrically controlled from ~10-5 to ~1 with little dependency on angle of incidence. This unique feature stems from the fact that the permittivity of doped graphene can be close to zero at a certain photon energy. The electrical controllability of evanescent coupling strength can enable novel design of optical devices. As a proof-of-concept, we designed a waveguide-type optical modulator of a novel operation principle: transmission modulation depends on the electrically controlled existence of a guided-mode of the waveguide, not the variation of the ohmic loss of graphene, resulting in a low insertion loss and a small device footprint.

  10. Attenuated total internal reflection Fourier transform infrared spectroscopy: a quantitative approach for kidney stone analysis.

    Science.gov (United States)

    Gulley-Stahl, Heather J; Haas, Jennifer A; Schmidt, Katherine A; Evan, Andrew P; Sommer, André J

    2009-07-01

    The impact of kidney stone disease is significant worldwide, yet methods for quantifying stone components remain limited. A new approach requiring minimal sample preparation for the quantitative analysis of kidney stone components has been investigated utilizing attenuated total internal reflection Fourier transform infrared spectroscopy (ATR-FT-IR). Calcium oxalate monohydrate (COM) and hydroxylapatite (HAP), two of the most common constituents of urinary stones, were used for quantitative analysis. Calibration curves were constructed using integrated band intensities of four infrared absorptions versus concentration (weight %). The correlation coefficients of the calibration curves range from 0.997 to 0.93. The limits of detection range from 0.07 +/- 0.02% COM/HAP where COM is the analyte and HAP is the matrix, to 0.26 +/- 0.07% HAP/COM where HAP is the analyte and COM is the matrix. This study shows that linear calibration curves can be generated for the quantitative analysis of stone mixtures provided the system is well understood especially with respect to particle size.

  11. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    Energy Technology Data Exchange (ETDEWEB)

    Pessanha, Sofia [Centro Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Carvalho, Maria Luisa, E-mail: luisa@cii.fc.ul.p [Centro Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Becker, Maria; Bohlen, Alex von [Institute for analytical Sciences, Bunsen-Kirchhoff-Str. 11, 44139 Dortmund (Germany)

    2010-06-15

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  12. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    International Nuclear Information System (INIS)

    Pessanha, Sofia; Carvalho, Maria Luisa; Becker, Maria; Bohlen, Alex von

    2010-01-01

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  13. Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

    Science.gov (United States)

    Smith, Kevin T.; Balouet, Jean Christophe; Shortle, Walter C.; Chalot, Michel; Beaujard, François; Grudd, Håkan; Vroblesky, Don A.; Burkem, Joel G.

    2014-01-01

    Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to distinguish dendrochemical effects of internal processes from environmental contamination. Calcium, potassium, and zinc are three marker cations that illustrate the influence of these processes. We found changes in cation chemistry in tree rings potentially due to biomineralization, development of cracks or checks, heartwood/sapwood differentiation, intra-annual processes, and compartmentalization of infection. Distinguishing internal from external processes that affect dendrochemistry will enhance the value of EDXRF for both physiological and forensic investigations.

  14. First combined total reflection X-ray fluorescence and grazing incidence X-ray absorption spectroscopy characterization of aeolian dust archived in Antarctica and Alpine deep ice cores

    Energy Technology Data Exchange (ETDEWEB)

    Cibin, G. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxon OX110DE (United Kingdom); IMONT/EIM, Ente Italiano della Montagna, P.za dei Caprettari 70, 00176 Roma (Italy); Universita' degli Studi di Roma Tre, Dipartimento di Scienze Geologiche, L.go S. Leonardo Murialdo 1, 00146 Roma (Italy)], E-mail: giannantonio.cibin@diamond.ac.uk; Marcelli, A. [INFN - Laboratori Nazionali di Frascati, P.O. Box 13, 00044 Frascati (Roma) (Italy); Maggi, V. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Sala, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Universita degli Studi di Milano, Dipartimento di Scienze della Terra ' A. Desio' , Sez. Mineralogia, Via Mangiagalli 34, 20133 Milano (Italy); Marino, F.; Delmonte, B. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Albani, S. [Universita degli Studi di Milano-Bicocca, Dipartimento di Scienze dell' Ambiente e del Territorio, Piazza della Scienza 1, 20126 Milano (Italy); Universita degli Studi di Siena, Dottorato in Scienze Polari, via Laterina 8, 53100 Siena (Italy); Pignotti, S. [IMONT/EIM, Ente Italiano della Montagna, P.za dei Caprettari 70, 00176 Roma (Italy)

    2008-12-15

    Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this work we performed the first preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores using grazing incidence geometry at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and total-reflection X-Ray Fluorescence and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Laboratory. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 {mu}g range.

  15. Monitoring environmental pollution of trace elements in tree-rings by synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Brienza, Sandra Maria B. [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil) Faculdade de Ciencias Matematicas, da Natureza e de Tecnologia da Informacao]. E-mail: sbrienza@unimep.br; Medeiros, Jean Gabriel S.; Tomazello Filho, Mario [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]. E-mail: jeangm@esalq.usp.br; mtomazel@esalq.usp.br; Zucchi, Orgheda L.A.D. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2005-07-01

    This paper aims to study the environmental pollution in the tree development, as a manner to evaluate its use as bioindicator in urban and country sides. The sample collecting was carry out in Piracicaba city, Sao Paulo State, that presents high level of environmental contamination of the water, soil and air, due industrial activities, vehicles combustion, sugar-cane leaves burning in the harvesting, etc. It was selected the Caesalpinia peltophoroides ('Sibipiruna') specie because its very used in urban arborization. It was employed the analytical technique named total reflection X-ray fluorescence (TXRF) to identify and quantify the elements and metals of nutritional and toxicological importance in the wood samples. The analysis was done in the Brazilian Synchrotron Light Laboratory, using a white beam for excitation and a Si(Li) detector for characteristic X-ray detection. It was quantified the P, K, Ca, Ti, Fe, Sr, Ba e Pb elements. (author)

  16. Monitoring environmental pollution of trace elements in tree-rings by synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    International Nuclear Information System (INIS)

    Moreira, Silvana; Vives, Ana Elisa S. de; Brienza, Sandra Maria B.; Medeiros, Jean Gabriel S.; Tomazello Filho, Mario; Zucchi, Orgheda L.A.D.; Nascimento Filho, Virgilio F.

    2005-01-01

    This paper aims to study the environmental pollution in the tree development, as a manner to evaluate its use as bioindicator in urban and country sides. The sample collecting was carry out in Piracicaba city, Sao Paulo State, that presents high level of environmental contamination of the water, soil and air, due industrial activities, vehicles combustion, sugar-cane leaves burning in the harvesting, etc. It was selected the Caesalpinia peltophoroides ('Sibipiruna') specie because its very used in urban arborization. It was employed the analytical technique named total reflection X-ray fluorescence (TXRF) to identify and quantify the elements and metals of nutritional and toxicological importance in the wood samples. The analysis was done in the Brazilian Synchrotron Light Laboratory, using a white beam for excitation and a Si(Li) detector for characteristic X-ray detection. It was quantified the P, K, Ca, Ti, Fe, Sr, Ba e Pb elements. (author)

  17. Determination of trace elements in honey from different regions in Rio de Janeiro State (Brazil) by total reflection X-ray fluorescence.

    Science.gov (United States)

    Ribeiro, Roberta de Oliveira Resende; Mársico, Eliane Teixeira; de Jesus, Edgar Francisco Oliveira; da Silva Carneiro, Carla; Júnior, Carlos Adam Conte; de Almeida, Eduardo; Filho, Virgílio Franco do Nascimento

    2014-04-01

    Trace and minor elements in Brazilian honey were analyzed by total reflection X-ray fluorescence spectroscopy. Up to 12 elements (K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, and Sr) were detected in 160 samples of honey from 4 regions of Rio de Janeiro State (Barra Mansa, Teresópolis, northern and southern Nova Friburgo). The results showed the samples from Teresópolis had higher rates of essential and nonessential elements than samples from the other regions, except for Ni. K and Ca were the most abundant elements in all samples, in the range of 116.5 to 987.0 μg g(-1) . Ni, Cu, Zn, Se, and Sr were identified in small concentrations (0.01 to 12.08 μg g(-1) ) in all samples, indicating a low level of contamination in all the regions. © 2014 Institute of Food Technologists®

  18. Use of total reflection X-ray fluorescence (TXRF) for the evaluation of heavy metal poisoning due to the improper use of a traditional ayurvedic drug.

    Science.gov (United States)

    Borgese, L; Zacco, A; Bontempi, E; Pellegatta, M; Vigna, L; Patrini, L; Riboldi, L; Rubino, F M; Depero, L E

    2010-09-05

    An Indian patient referred to Clinica del Lavoro 'L.Devoto' of Milano showed clinical signs of heavy metal poisoning, possibly related to a sustained 6-month use of approx. 3 g/day of a traditional preparation (a whitish powder with a 'mineral' appearance) to treat urological problems. To confirm the causal relationship between the disease and the use of such product, metal testing was performed on the patient's hair and the ayurvedic remedy samples by total reflection X-ray fluorescence (TXRF). For TXRF analysis 1-cm cut of the patient's hair was directly deposited onto the quartz glass sample carrier, then 10 microl of nitric acid 65% were added and dried in air. TXRF showed high versatility, rapid and simultaneous element detection, and short analysis time, thus supporting a wider use in emergency medicine and in forensic analyses. 2010 Elsevier B.V. All rights reserved.

  19. Application of the total reflection X-ray fluorescence method to the elemental analysis of brain tumors of different types and grades of malignancy

    International Nuclear Information System (INIS)

    Lankosz, M.W.; Grzelak, M.; Ostachowicz, B.; Wandzilak, A.; Szczerbowska-Boruchowska, M.; Wrobel, P.; Radwanska, E.; Adamek, D.

    2014-01-01

    The process of carcinogenesis may influence normal biochemical reactions leading to alterations in the elemental composition of the tissue. Total reflection X-ray fluorescence analysis (TXRF) was applied to the elemental analysis of different brain tumors. The following elements were present in all the neoplastic tissues analyzed: K, Ca, Fe, Cu, Zn and Rb. The results of the analysis showed that the elemental composition of a relatively small fragment of tissue represents satisfactorily the biochemical “signature” of a cancer. On the basis of the element concentrations determined, it was possible to differentiate between some types of brain tumors. - Highlights: • Elemental composition represents the biochemical signature of brain cancer. • The element levels differentiate some types of brain tumors. • TXRF spectrometry is a useful tool for elemental trace analysis of brain cancer

  20. Reference materials for quality assurance in sea-water analysis: performance of total-reflection x-ray fluorescence in the intercomparison and certification stages

    International Nuclear Information System (INIS)

    Freimann, P.; Schmidt, D.; Neubauer-Ziebarth, A.

    1993-01-01

    The certification of a sea-water reference material (CRM 403) was completed by the Community Bureau of Reference (BCR) of the Commission of the European Communities during an intercomparison exercise. A feasibility study on estuarine water was undertaken. In both studies total-reflection X-ray fluorescence analysis (TXRF) was used for the determination of V, Mn, Fe, Co, Ni, Cu, Zn, Pb and U on the nmol/kg level. The enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. In this paper, the high performance of our TXRF results is compared to other analytical techniques like voltammetric and atomic absorption methods. (author)

  1. Determination of metals by total reflection X-ray fluorescence and evaluation of toxicity of a river impacted by coal mining in the south of Brazil.

    Science.gov (United States)

    Lattuada, R M; Menezes, C T B; Pavei, P T; Peralba, M C R; Dos Santos, J H Z

    2009-04-30

    Metal (Fe, Mn, Zn, Ni, Cd, and Pb) concentrations in the region of Criciuma (Brazil), a region impacted by coal mining, were determined in water and sediments using total reflection X-ray fluorescence (TXRF) spectroscopy. Samples were collected from the Mãe Luzia River (south Brazil) at five different stations, from the source down to the river mouth (Ararangua estuary). Water and sediment toxicity were also evaluated using bioassays with Daphnia magna as the bioindicator. The metal present in the highest concentrations both in water (1.3-11 mg L(-1)) and in sediments (34-142 mg L(-1)) was iron. Results suggest an influence of coal mining on the aquatic receptors, showing a clear relationship between metal content (mostly Fe) and ecotoxicity.

  2. Application of the total reflection X-ray fluorescence method to the elemental analysis of brain tumors of different types and grades of malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Lankosz, M.W., E-mail: Marek.Lankosz@fis.agh.edu.pl [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow (Poland); Grzelak, M.; Ostachowicz, B.; Wandzilak, A.; Szczerbowska-Boruchowska, M.; Wrobel, P. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow (Poland); Radwanska, E.; Adamek, D. [Department of Neuropathology, Chair of Pathomorphology, Faculty of Medicine. Jagiellonian University, Krakow (Poland)

    2014-11-01

    The process of carcinogenesis may influence normal biochemical reactions leading to alterations in the elemental composition of the tissue. Total reflection X-ray fluorescence analysis (TXRF) was applied to the elemental analysis of different brain tumors. The following elements were present in all the neoplastic tissues analyzed: K, Ca, Fe, Cu, Zn and Rb. The results of the analysis showed that the elemental composition of a relatively small fragment of tissue represents satisfactorily the biochemical “signature” of a cancer. On the basis of the element concentrations determined, it was possible to differentiate between some types of brain tumors. - Highlights: • Elemental composition represents the biochemical signature of brain cancer. • The element levels differentiate some types of brain tumors. • TXRF spectrometry is a useful tool for elemental trace analysis of brain cancer.

  3. Quantification of modifiers in advanced materials based on zinc oxide by total reflection X-ray fluorescence and inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Filatova, Daria G.; Alov, Nikolai V.; Vorobyeva, Natalia A.; Rumyantseva, Marina N.; Sharanov, Pavel Yu.; Seregina, Irina F.; Gaskov, Alexander M.

    2016-04-01

    A novel approach to quantification of Ga and Zn modifiers in advanced materials based on zinc oxide is presented. The approach includes a combination of total reflection X-ray fluorescence (TXRF) and inductively coupled plasma mass spectrometry (ICP-MS) for determination and validation of the results. It is suggested to use aqueous standards for the direct determination of elements in powder samples by TXRF with a relative standard deviation no more than sr = 0.11. The accuracy of these results was proved by ICP-MS after the sample decomposition, sr(In) = 0.05, sr(Ga) = 0.06 and sr(Zn) = 0.06. It was established that there is a possibility to determine indium above 300 ppb on the background of K-M3 line of argon.

  4. Total reflection X-ray fluorescence measurements of S and P in proteins using a vacuum chamber specially designed for low Z elements

    Science.gov (United States)

    Rauwolf, M.; Vanhoof, C.; Tirez, K.; Maes, E.; Ingerle, D.; Wobrauschek, P.; Streli, C.

    2014-11-01

    As the ratio of phosphorus and sulfur in proteins allows the determination of the phosphorylation degree in proteins, the absolute determination of phosphorus and sulfur in organic samples is of growing interest. While it takes some effort to quantify phosphorus and sulfur with inductively coupled quadrupole plasma mass spectrometry (ICP-QMS), total reflection X-ray fluorescence analysis (TXRF) allows easy quantification. In the presented work, the low Z TXRF spectrometer at the Atominstitut was used to analyze phosphorus and sulfur in proteins. Although the preparation of the protein samples proved to be more difficult than originally expected, it could be shown that TXRF is well suited for the determination of P and S in proteins. The obtained lower limits of detection (LLD) for P and S in proteins were extrapolated for 1000s and were 34 pg and 19 pg, respectively. The importance of height scans for each sample to exclude heterogeneities was demonstrated.

  5. Fast method for multielemental analysis of plants and discrimination according to the anatomical part by total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    De la Calle, Inmaculada; Costas, Marta; Cabaleiro, Noelia; Lavilla, Isela; Bendicho, Carlos

    2013-05-01

    Fast and reliable analytical methodologies are required for quality control of plants in order to assure human health. Ultrasound-assisted extraction in combination with total reflection X-ray fluorescence is proposed as a fast and simple method for multielemental analysis of plants on a routine basis. For this purpose, five certified reference materials have been analysed for the determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb. Different extractant media (acids and oxidants) were tried. A mixture of diluted HNO(3)+HCl+HF, was selected as the best option for the achievement of complete extractions. Accurate and precise results can be reached in most cases along with a high sample throughput. Different plants (i.e., herbs, spices and medicinal plants) were analysed. Linear discriminant analysis together with the elemental concentrations allowed the differentiation of commercial preparations corresponding to flower, fruit and leaf. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Separation and enrichment of palladium and gold in biological and environmental samples, adapted to the determination by total reflection X-ray fluorescence.

    Science.gov (United States)

    Messerschmidt, J; von Bohlen, A; Alt, F; Klockenkämper, R

    2000-03-01

    The reductive co-precipitation of trace and ultra-trace elements together with mercury followed by complete evaporation of the mercury makes it possible to determine palladium and gold by total reflection X-ray fluorescence. Both elements can be detected without interferences at optimal sensitivity in the pg range. Thus, detection limits of, e.g., 2.5 ng L-1 for palladium and 2.0 ng L-1 for gold, in urine, were obtained. The precision was determined to 0.04 at a palladium concentration of about 200 ng L-1 urine and to 0.19 at a gold concentration of only 18 ng L-1. The recovery for a urine sample spiked with known amounts of palladium and gold amounted to > 95%. Results of the combined procedure are given for the determination of palladium and gold in the urine of non-exposed and occupationally exposed persons and in some other environmentally relevant samples.

  7. Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshihide, E-mail: e0827@mosk.tytlabs.co.jp; Nishimura, Yusaku F.; Suzuki, Ryo; Beniya, Atsushi; Isomura, Noritake [Toyota Central R& D Labs., Inc., Yokomichi 41-1, Nagakute, Aichi 480-1192 (Japan); Uehara, Hiromitsu; Asakura, Kiyotaka; Takakusagi, Satoru [Catalysis Research Center, Hokkaido University, Kita 21-10, Sapporo, Hokkaido 001-0021 (Japan); Nimura, Tomoyuki [AVC Co., Ltd., Inada 1450-6, Hitachinaka, Ibaraki 312-0061 (Japan)

    2016-03-15

    A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstrated by a successful PTRF-XAFS study of Pt{sub 4} clusters deposited on a TiO{sub 2}(110) surface.

  8. Meaning, Internalization, and Externalization: Toward a Fuller Understanding of the Process of Reflection and Its Role in the Construction of the Self

    Science.gov (United States)

    Le Cornu, Alison

    2009-01-01

    The study of the process of reflection has a dignified history. However, few have linked reflection to the development of the self in such a way that the form of reflection is understood to influence the resultant type of self. This article explores the process of reflection using a framework of meaning making, internalization, and externalization…

  9. Elemental concentration analysis in brain of young, adult and old wistar rats by X-ray total reflection fluorescence with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Serpa, Renata F.B.; Jesus, Edgar F.O. de; Lopes, Ricardo T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Lab. de Instrumentacao Nuclear]. E-mail: renata@lin.ufrj.br; Anjos, Marcelino J. dos [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica]. E-mail: marcelin@lin.ufrj.br; Carmo, Maria da Graca T. do [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Nutricao]. E-mail: tcarmo@editema.com.br; Rocha, Monica S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Dept. de Farmacologia]. E-mail: mrocha@farmaco.ufrj.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil]. E-mail: silvana@fec.unicamp.br; Martinez, Ana Maria B. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Dept. de Histologia]. E-mail: martinez@histo.ufrj.br

    2005-07-01

    The mainly goal of this work is to compare the elemental concentrations with different postnatal ages (2, 8, 20, 48 and 72 weeks) at three different regions of the rat brain, namely temporal cortex, entorhinal cortex and hippocampus by X-Ray Total Reflection Fluorescence with Synchrotron Radiation (SR-TXRF). The advantages for this analytical multielemental technique are: low background, linear relation in the quantification analysis and low detection limit (ngg{sup -1}). The fluorescence measurements were carried out at XRF beamline at the Brazilian Light Synchrotron Laboratory (Campinas, Brazil). It was possible to determine the following elements: Ti, Mn, Fe, Cu, Zn, Br, Rb and Sr (at trace level) and P, S, Cl, K and Ca (at major levels) were determined in the brain. In general, Fe levels were more pronounced in entorhinal cortex. There was also observed that the hippocampus of the old female rat presented the highest concentrations for Al, P, S, K, and Zn. In contrast to this, the hippocampus and entorhinal cortex presented the less levels for Al and K in the young animals. On the other hand, Cl levels were more conspicuous in the entorhinal cortex of the oldest male animal studied. (author)

  10. Whole-surface analysis of semiconductor wafers by accumulating short-time mapping data of total-reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Mori, Yoshihiro; Uemura, Kenichi; Lizuka, Yoshinori

    2002-03-01

    Total-reflection X-ray fluorescence (TXRF) spectrometry with no chemical preconcentration, often called "straight-TXRF", is now widely used in the semiconductor industry. The small detection area of TXRF enablesmapping measurement of contamination of the semiconductor surface, which is very useful in process characterization. However, the small detection area had been believed to limit rapid whole-surface analysis. Contrary to this general understanding, in this study we demonstrated that a new method, called "sweeping-TXRF", which is essentially short-time multipoint mapping by straight-TXRF, can rapidly provide an average concentration. A considerable problem of this method is the contribution of errors in glancing angle and areal element distribution to the fluorescence. Using statistics, we examined the errors and demonstrated that most of them are canceled and are not significant in actual semiconductor applications. The results of an experiment that measured localized 6 x 10(10) atoms cm(-2) nickel contamination supported the above conclusion. Applying sweeping-TXRF to existing TXRF instruments is easy-the only requirement is a small software modification. We believe that sweeping-TXRF will be utilized for rapid whole-surface analysis in many fields, especially in the semiconductor industry.

  11. Nanoliter deposition unit for pipetting droplets of small volumes for Total Reflection X-ray Fluorescence applications

    Energy Technology Data Exchange (ETDEWEB)

    Wastl, A., E-mail: awastl@ati.ac.at; Stadlbauer, F.; Prost, J.; Horntrich, C.; Kregsamer, P.; Wobrauschek, P.; Streli, C.

    2013-04-01

    A nanoliter droplet deposition unit was developed and characterized for application of sample preparation in TXRF. The droplets produced on quartz reflectors as well as on wafers show a good reproducibility, also the accuracy of the pipetted volume could be proved by a quantitative TXRF analysis using an external standard. The samples were found to be independent of rotation of the sample carrier. Angle scans showed droplet residue behavior, and the fluorescence signal is relatively invariant of the angle of incidence below the critical angle, which is useful for producing standards for external calibration for semiconductor surface contamination measurements by TXRF. Further it could be demonstrated that the nanoliter deposition unit is perfectly able to produce patterns of samples for applications like the quantification of aerosols collected by impactors. - Highlights: ► The system produces very accurate and reliable samples. ► Volumes below 1 μl can be applied. ► Precise patterns can be deposited on different sample carriers. ► Typical angle independency below critical angle can be shown.

  12. Room temperature trapping of stibine and bismuthine onto quartz substrates coated with nanostructured palladium for total reflection X-ray fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Vanesa; Costas-Mora, Isabel; Lavilla, Isela; Bendicho, Carlos, E-mail: bendicho@uvigo.es

    2015-05-01

    In this work, a novel method for determining Sb and Bi based on the trapping of their covalent hydrides onto quartz reflectors coated with immobilized palladium nanoparticles (Pd NPs) followed by total reflection X-ray fluorescence (TXRF) analysis is proposed. Pd NPs were synthesized by chemical reduction of the metal precursor using a mixture of water:ethanol as mild reducing agent. Silanization using 3-mercaptopropyltrimethoxysilane (MPTMS) was performed for the immobilization of Pd NPs onto the quartz substrates. Volatile hydrides (stibine and bismuthine) generated by means of a continuous flow system were flushed onto the immobilized Pd NPs and retained by catalytic decomposition. As a result of the high catalytic activity of the nanostructured film, trapping can be performed at ambient temperature with good efficiency. Limits of detection (LODs) were 2.3 and 0.70 μg L{sup −1} for Sb and Bi, respectively. Enrichment factors of 534 and 192 were obtained for Sb and Bi, respectively. The new method was applied for the analysis of several matrices (milk, soil, sediment, cutaneous powder). Recoveries were in the range of 98.4–101% for both elements with a relative standard deviation of 2.5% (N = 5). - Highlights: • A novel method for trapping covalent hydrides of antimony and bismuth is proposed. • Emphasis is placed on the application of Pd nanoparticles as trapping surface. • The nanostructured surface provides high catalytic activity at ambient temperature. • Analysis by total reflection X-ray fluorescence is performed. • Determination of Bi and Sb in different matrices is carried out.

  13. How Is Buddhism Relevant to Career Counseling in an International High School in Hong Kong? A Counsellor's Reflection

    Science.gov (United States)

    Ng, Vinci; Yuen, Mantak

    2015-01-01

    This paper reflects upon the relevance of Buddhism to counselling in general and to career counseling in particular by discussing a program implemented at an international school in Hong Kong. The authors provide an analysis of the pertinent literature related to relevant concepts within Buddhism. This topic has not yet been adequately researched…

  14. Reflections on International Comparative Education Survey Methodology: A Case Study of the European Survey on Language Competences

    Science.gov (United States)

    Ashton, Karen

    2016-01-01

    This paper reflects on the methodology used in international comparative education surveys by conducting a systematic review of the European Survey on Language Competences (ESLC). The ESLC was administered from February to March 2011, with final results released in June 2012. The survey tested approximately 55,000 students across 14 European…

  15. Measurements of long-range interactions between protein-functionalized surfaces by total internal reflection microscopy.

    Science.gov (United States)

    Wang, Zhaohui; Gong, Xiangjun; Ngai, To

    2015-03-17

    Understanding the interaction between protein-functionalized surfaces is an important subject in a variety of protein-related processes, ranging from coatings for biomedical implants to targeted drug carriers and biosensors. In this work, utilizing a total internal reflection microscope (TIRM), we have directly measured the interactions between micron-sized particles decorated with three types of common proteins concanavalin A (ConA), bovine serum albumin (BSA), lysozyme (LYZ), and glass surface coated with soy proteins (SP). Our results show that the protein adsorption greatly affects the charge property of the surfaces, and the interactions between those protein-functionalized surfaces depend on solution pH values. At pH 7.5-10.0, all these three protein-functionalized particles are highly negatively charged, and they move freely above the negatively charged SP-functionalized surface. The net interaction between protein-functionalized surfaces captured by TIRM was found as a long-range, nonspecific double-layer repulsion. When pH was decreased to 5.0, both protein-functionalized surfaces became neutral and double-layer repulsion was greatly reduced, resulting in adhesion of all three protein-functionalized particles to the SP-functionalized surface due to the hydrophobic attraction. The situation is very different at pH = 4.0: BSA-decorated particles, which are highly charged, can move freely above the SP-functionalized surfaces, while ConA- and LYZ-decorated particles can only move restrictively in a limited range. Our results quantify these nonspecific kT-scale interactions between protein-functionalized surfaces, which will enable the design of surfaces for use in biomedical applications and study of biomolecular interactions.

  16. Attenuated total internal reflection infrared microscopy of multilayer plastic packaging foils.

    Science.gov (United States)

    van Dalen, Gerard; Heussen, Patricia C M; den Adel, Ruud; Hoeve, Robert B J

    2007-06-01

    Multilayer plastic foils are important packaging materials that are used to extend the shelf life of food products and drinks. Fourier transform infrared (FT-IR) spectroscopic imaging using attenuated total internal reflection (ATR) can be used for the identification and localization of different layers in multilayer foils. A new type of ATR crystal was used in combination with a linear array detector through which large sample areas (400 x 400 microm(2)) could be imaged with a pixel size of 1.6 microm. The method was tested on laminated plastic packing materials containing 5 to 12 layers. The results of the identification of the different materials using ATR-FT-IR were compared with differential scanning calorimetry (DSC) and the layer thickness of the individual layers measured by ATR-FT-IR was compared with polarized light microscopy (LM) and scanning electron microscopy (SEM). It has been demonstrated that individual layers with a thickness of about 3 microm could be identified in multilayer foils with a total thickness ranging from 100 to 150 microm. The results show a spatial resolution of about 4 microm (measured at wavenumbers ranging from 1000 to 1730 cm(-1)), which is about a factor of two better than can be obtained using transmission FT-IR imaging. An additional advantage of ATR is the ease of sample preparation. A good correspondence was found between visible and FT-IR images. The results of ATR-FT-IR imaging were in agreement with those obtained by LM, SEM, and DSC. ATR-FT-IR is superior to the combination of these techniques because it delivers both spatial and chemical information.

  17. Determination of trace amounts of hexavalent chromium in drinking waters by dispersive microsolid-phase extraction using modified multiwalled carbon nanotubes combined with total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Bahadir, Z.; Bulut, V. N.; Hidalgo, M.; Soylak, M.; Marguí, E.

    2015-05-01

    A methodology based on the combination of dispersive microsolid-phase extraction (DMSPE) with total reflection X-ray fluorescence (TXRF) spectrometry is proposed for the determination of hexavalent chromium in drinking waters. Multiwalled carbon nanotubes (MWCNTs) modified with the anionic exchanger tricaprylmethylammonium chloride (Aliquat 336) were used as solid sorbents. After the sorption process of Cr(VI) on the modified MWCNTs, the aqueous sample was separated by centrifugation and the loaded MWCNTs were suspended using a small volume of an internal standard solution and analyzed directly by a benchtop TXRF spectrometer, without any elution step. Parameters affecting the extraction process (pH and volume of the aqueous sample, amount of MWCNTs, extraction time) and TXRF analysis (volume of internal standard, volume of deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cr(VI) at trace levels. Using the best analytical conditions, it was found that the minimum Cr(VI) content that can be detected in an aqueous solution was 3 μg L- 1. This value is almost 20 times lower than the maximum hexavalent chromium content permissible in drinking waters, according to the World Health Organization (WHO). Recoveries for spiked tap and mineral water samples were, in most cases, in the range of 101-108% which demonstrates the suitability of the TXRF methodology for monitoring Cr(VI) at trace levels in drinking water samples.

  18. Biomonitoring of environmental pollution using growth tree rings of Tipuana tipu: Quantification by synchrotron radiation total reflection X-ray fluorescence

    Science.gov (United States)

    Geraldo, S. M.; Canteras, F. B.; Moreira, S.

    2014-02-01

    Currently, many studies use the bioindicators to qualitatively and/or quantitatively measure pollution. The analyses of tree growth rings represent one such bioindicator as changes in the environment are often recorded as impressions in the wood. The main objective of the present study is to examine the growth rings of Tipuana tipu - a member of the Leguminosae family that is native to Argentina and Bolivia and was introduced in Brazil as an ornamental plant - for potentially toxic elements. T. tipu is one of the most common trees in the urban landscape of Sao Paulo city and would provide an accurate reflection of environment changes. Tree ring samples previously dated using Synchrotron Radiation Total Reflection X-ray Fluorescence were collected from strategic locations in Sao Paulo. These locations include Piracicaba (SP) that has little access and small flow traffic and the campus of the University of São Paulo. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, samples collected from the campus of University of São Paulo (Butantã), showed the highest toxicity, with concentrations above the tolerable limit for the elements: Cr, Cu, and Pb. For the samples collected in Piracicaba city, one sample presented highest concentrations for the majority of the elements when compared to the other four samples collected at the same place, exceeding the toxicity limits for: Cr, Ni, Cu, and Pb.

  19. Airborne particulate matter (PM) filter analysis and modeling by total reflection X-ray fluorescence (TXRF) and X-ray standing wave (XSW).

    Science.gov (United States)

    Borgese, L; Salmistraro, M; Gianoncelli, A; Zacco, A; Lucchini, R; Zimmerman, N; Pisani, L; Siviero, G; Depero, L E; Bontempi, E

    2012-01-30

    This work is presented as an improvement of a recently introduced method for airborne particulate matter (PM) filter analysis [1]. X-ray standing wave (XSW) and total reflection X-ray fluorescence (TXRF) were performed with a new dedicated laboratory instrumentation. The main advantage of performing both XSW and TXRF, is the possibility to distinguish the nature of the sample: if it is a small droplet dry residue, a thin film like or a bulk sample. Another advantage is related to the possibility to select the angle of total reflection to make TXRF measurements. Finally, the possibility to switch the X-ray source allows to measure with more accuracy lighter and heavier elements (with a change in X-ray anode, for example from Mo to Cu). The aim of the present study is to lay the theoretical foundation of the new proposed method for airborne PM filters quantitative analysis improving the accuracy and efficiency of quantification by means of an external standard. The theoretical model presented and discussed demonstrated that airborne PM filters can be considered as thin layers. A set of reference samples is prepared in laboratory and used to obtain a calibration curve. Our results demonstrate that the proposed method for quantitative analysis of air PM filters is affordable and reliable without the necessity to digest filters to obtain quantitative chemical analysis, and that the use of XSW improve the accuracy of TXRF analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Communication Education and International Audiences: Reflections on Instructional Challenges and Pedagogical Strategy

    Science.gov (United States)

    Campbell, Heather; Strawser, Michael G.; George, Stephen

    2016-01-01

    As the movement toward international education continues, institutions must be proficient when reaching and teaching international students. Instructors should engage unique learning styles, address individual student needs, and take part in additional training to effectively teach international student learners. These instructional imperatives…

  1. Total reflection X-ray fluorescence spectrometric determination of elements in water hyacinth from the Lerma River

    International Nuclear Information System (INIS)

    Tejeda, S.; Zarazua, G.; Avila-Perez, P.; Carapia-Morales, L.; Martinez, T.

    2010-01-01

    The Lerma River is one of the most polluted body water in Mexico. For this reason, only the highly resistant organisms such as water hyacinth are able to reproduce in this river. The aim of this work was to evaluate the concentration of K, S, Fe, Ca, Mn, Ti, Zn, Sr, Rb, Cu, Cr, Ni, Pb and Br in roots of water hyacinth (Eichhornia crassipes) from the Lerma River. The samples were collected from five sites in the river and analyzed in triplicate using a TXRF Spectrometer 'TX-2000 Ital Structures' with a Si(Li) detector and a resolution of 140 eV (FWHM) at Mn Kα. A Mo tube (40 kV, 30 mA) with 17.4 KeV excitation energy was used for a counting time of 500 s. Results show that the average metal concentration in the water hyacinth roots decrease in the following order: K (9698.2 μg/g) > S (7593.3 μg/g) > Fe (4406.6 μg/g) > Ca (2601.8 μg/g) > Mn (604.2 μg/g) > Ti (230.7 μg/g) > Zn (51.65 μg/g) > Sr (43.55 μg/g) > Rb (18.61 μg/g) > Cu (12.78 μg/g) > Cr (6.45 μg/g) > Ni (4.68 μg/g) > Pb (4.32 μg/g) > Br (4.31 μg/g) and the bioconcentration factors in the water hyacinth decrease in the sequence: Ti > Fe > Mn > Cu > Ni > Zn > S > Pb > Rb > K > Cr > Sr > Br > Ca. The concentrations in roots of water hyacinth reflect the high pollution level of the river.

  2. Quantum electrodynamics of the internal source x-ray holographies: Bremsstrahlung, fluorescence, and multiple-energy x-ray holography

    International Nuclear Information System (INIS)

    Miller, G.A.; Sorensen, L.B.

    1997-01-01

    Quantum electrodynamics (QED) is used to derive the differential cross sections measured in the three new experimental internal source ensemble x-ray holographies: bremsstrahlung (BXH), fluorescence (XFH), and multiple-energy (MEXH) x-ray holography. The polarization dependence of the BXH cross section is also obtained. For BXH, we study analytically and numerically the possible effects of the virtual photons and electrons which enter QED calculations in summing over the intermediate states. For the low photon and electron energies used in the current experiments, we show that the virtual intermediate states produce only very small effects. This is because the uncertainty principle limits the distance that the virtual particles can propagate to be much shorter than the separation between the regions of high electron density in the adjacent atoms. We also find that using the asymptotic form of the scattering wave function causes about a 5 10% error for near forward scattering. copyright 1997 The American Physical Society

  3. Double fluorescent flow cytometric assessment of bacterial internalization and binding by epithelial cells

    NARCIS (Netherlands)

    de Boer, E. C.; Bevers, R. F.; Kurth, K. H.; Schamhart, D. H.

    1996-01-01

    This study describes a new flow cytometric method for assessment of phagocytosis of specific bacteria (bacillus Calmette-Guérin (BCG) and Escherichia coli) by bladder epithelial cells. The internalization assay consisted of labeling bacteria chemically with fluorescein isothiocyanate (FITC).

  4. Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

    International Nuclear Information System (INIS)

    Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T.; Bellido, Alfredo Victor B.; Anjos, Marcelino J.

    2011-01-01

    Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly (α = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

  5. Evaluation of growth tree rings of Tipuana Tipu as biomonitoring of environmental pollution by synchrotron radiation total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Moreira, Silvana; Geraldo, Simoni Michetti; Canteras, Felippe Benavente

    2013-01-01

    The bioindicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to pollutant substances. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The selected species, Tipuana Tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as an ornamental plant. It is one of the most common trees in the urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of potentially toxic elements in samples of growth the tree rings of Tipuana Tipu, previously dated, collected in strategically locations of Sao Paulo, using Synchrotron Radiation Total Reflection X-Ray Fluorescence. Samples were also collected in the Piracicaba (SP), local of little access and small flow traffic. The SR-TXRF analysis was carried out in the X-ray Fluorescence Beamline at the Brazilian Synchrotron Light Source Laboratory, located in Campinas city, Sao Paulo State, Brazil. Some trace elements present concentrations higher than considered as normal in some periods. In this paper the highest value for Pb was 123.54 μg.g -1 considered as threshold value was observed for the period 1998 to 2000 for University of Sao Paulo, Butanta site. For the same period excessive level was also observed for samples collected in Piracicaba city. In Sao Paulo city, sample collected in the campus of University of Sao Paulo (Butanta), showed the highest toxicity, with concentration above the tolerable limit for Ti, Cr and Cu. For the samples collected in Piracicaba city the concentrations of Cr, Ni, Cu, and Pb exceeding the toxicity limits. (author)

  6. Evaluation of growth tree rings of Tipuana Tipu as biomonitoring of environmental pollution by synchrotron radiation total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Geraldo, Simoni Michetti; Canteras, Felippe Benavente, E-mail: silvana@fec.unicamp.br, E-mail: felippe.canteras@gmail.com [Universidade Estadual de Campinas (FEC/UNICAMP), Campinas, SP (Brazil). Dept. de Saneamento e Ambiente

    2013-07-01

    The bioindicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to pollutant substances. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The selected species, Tipuana Tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as an ornamental plant. It is one of the most common trees in the urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of potentially toxic elements in samples of growth the tree rings of Tipuana Tipu, previously dated, collected in strategically locations of Sao Paulo, using Synchrotron Radiation Total Reflection X-Ray Fluorescence. Samples were also collected in the Piracicaba (SP), local of little access and small flow traffic. The SR-TXRF analysis was carried out in the X-ray Fluorescence Beamline at the Brazilian Synchrotron Light Source Laboratory, located in Campinas city, Sao Paulo State, Brazil. Some trace elements present concentrations higher than considered as normal in some periods. In this paper the highest value for Pb was 123.54 μg.g{sup -1} considered as threshold value was observed for the period 1998 to 2000 for University of Sao Paulo, Butanta site. For the same period excessive level was also observed for samples collected in Piracicaba city. In Sao Paulo city, sample collected in the campus of University of Sao Paulo (Butanta), showed the highest toxicity, with concentration above the tolerable limit for Ti, Cr and Cu. For the samples collected in Piracicaba city the concentrations of Cr, Ni, Cu, and Pb exceeding the toxicity limits. (author)

  7. Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T., E-mail: catarine@lin.ufrj.b, E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear. Lab. de Instrumentaco Nuclear; Carvalho, Silvia M.F., E-mail: silvia@hemorio.rj.gov.b [State Institute of Hematology Arthur de Siqueira Cavalcanti (HEMORIO), Rio de Janeiro, RJ (Brazil); Bellido, Alfredo Victor B., E-mail: alfredo@ien.gov.b [Federal Fluminense University (UFF), Niteroi, RJ (Brazil). Chemistry Inst.; Anjos, Marcelino J., E-mail: marcelin@lin.ufrj.b [State University of Rio de Janeiro (UERJ), RJ (Brazil). Physics Inst.

    2011-07-01

    Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly ({alpha} = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

  8. Do people ruminate because they haven't digested their goals? The relations of rumination and reflection to goal internalization and ambivalence

    DEFF Research Database (Denmark)

    Thomsen, Dorthe Kirkegaard; Tønnesvang, Jan; Schnieber, Anette

    2011-01-01

    , and internalization of self-regulation and goals. In Study 1, rumination was related to less internalized self-regulation, whereas reflection was related to more internalized self-regulation. In Study 2, rumination was related to less internalized self-regulation and goals as well as to more avoidance- and extrinsic...

  9. Internal versus external service quality: reflections of employees and customers in the mirror

    Directory of Open Access Journals (Sweden)

    Emir Ganic

    2017-09-01

    perceptions of the quality of university services. Perceptions of internal service quality are also positively related to students’ perceptions of reliability, responsiveness and quality assurance. Conclusions: The perceptions of internal service quality by faculty members are positively related to students’ perceptions of quality. Comparing the levels of internal and external service quality will help managers define priorities for allocating resources to improve quality.

  10. All-optical microscope autofocus based on an electrically tunable lens and a totally internally reflected IR laser.

    Science.gov (United States)

    Bathe-Peters, M; Annibale, P; Lohse, M J

    2018-02-05

    Microscopic imaging at high spatial-temporal resolution over long time scales (minutes to hours) requires rapid and precise stabilization of the microscope focus. Conventional and commercial autofocus systems are largely based on piezoelectric stages or mechanical objective actuators. Objective to sample distance is either measured by image analysis approaches or by hardware modules measuring the intensity of reflected infrared light. We propose here a truly all-optical microscope autofocus taking advantage of an electrically tunable lens and a totally internally reflected infrared probe beam. We implement a feedback-loop based on the lateral position of a totally internally reflected infrared laser on a quadrant photodetector, as an indicator of the relative defocus. We show here how to treat the combined contributions due to mechanical defocus and deformation of the tunable lens. As a result, the sample can be kept in focus without any mechanical movement, at rates up to hundreds of Hertz. The device requires only reflective optics and can be implemented at a fraction of the cost required for a comparable piezo-based actuator.

  11. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy; Determinacion de plomo en esmaltado de barro por Fluorescencia de rayos X en reflexion total y Microscopia Electronica de Barrido

    Energy Technology Data Exchange (ETDEWEB)

    Zarazua O, G.; Carapia M, L. [Instituto Nacional de Investigaciones Nucleares, C.P. 52045 Estado de Mexico (Mexico)

    2000-07-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  12. Troubling Metaphors and International Student Adjustment: Reflections from a Transnational Place

    Science.gov (United States)

    Starr-Glass, David

    2017-01-01

    On many campuses, offices of International Student Affairs address the perceived needs of international students. However, a number of underlying assumptions and persistent metaphors shape these efforts and influence their outcomes. All students are uniquely different and face equally different challenges in adjusting to higher education. Labeling…

  13. Living and Learning Internationally for a Viable Future: Reflecting on UNESCO CONFINTEA VI

    Science.gov (United States)

    Henschke, John A.

    2012-01-01

    International travel has the potential to expand one's learning horizons exponentially, especially with the abundantly enriching experiences of adult, continuing, and lifelong learning conferences. CONFINTEA VI (The Sixth World International Conference in Adult Education) sponsored by the United Nations Educational, Scientific, and Cultural…

  14. Education for International Mindedness: Life History Reflections on Schooling and the Shaping of a Cosmopolitan Outlook

    Science.gov (United States)

    Wright, Katie; Buchanan, Emma

    2017-01-01

    The development of "international mindedness" is an established aim of international education and has recently gained prominence in national school systems. Despite its increasing salience, it remains an ambiguous construct and an understudied aspect of schooling. It is implicated in globalized educational markets and attempts to…

  15. Reflections and Experiences of Student Paramedics Undertaking International Work-Integrated Learning Placements

    Science.gov (United States)

    Simpson, Paul; Thyer, Liz; Van Nugteren, Ben; Mitchell, Glen; Werner, Sarah

    2016-01-01

    International work-integrated learning (WIL) is increasingly common in health-related programs in Australian universities. Paramedicine programs are beginning to explore international WIL in line with the globalization of paramedicine as a profession and the national higher education emphasis on outward bound learning experiences. Using…

  16. Use of high-intensity sonication for pre-treatment of biological tissues prior to multielemental analysis by total reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    De La Calle, Inmaculada; Costas, Marta; Cabaleiro, Noelia; Lavilla, Isela; Bendicho, Carlos

    2012-01-01

    In this work, two ultrasound-based procedures are developed for sample preparation prior to determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se and Sr in biological tissues by total reflection X-ray fluorescence spectrometry. Ultrasound-assisted extraction by means of a cup-horn sonoreactor and ultrasonic-probe slurry sampling were compared with a well-established procedure such as magnetic agitation slurry sampling. For that purpose, seven certified reference materials and different real samples of animal tissue were used. Similar accuracy and precision is obtained with the three sample preparation approaches tried. Limits of detection were dependent on both the sample matrix and the sample pre-treatment used, best values being achieved with ultrasound-assisted extraction. Advantages of ultrasound-assisted extraction include reduced sample handling, decreased contamination risks (neither addition of surfactants nor use of foreign objects inside the extraction vial), simpler background (no solid particles onto the sample carrier) and improved recovery for some elements such as P. A mixture of 10% v/v HNO 3 + 20–40% v/v HCl was suitable for extraction from biological tissues. - Highlights: ► We implement high-intensity sonication for pre-treatment of biological tissues. ► Multielemental analysis is performed by total reflection X-ray spectrometry. ► Ultrasound-based procedures are developed and compared to conventional slurry preparation. ► Features such as background, recovery and sample handling are favored by using ultrasonic extraction.

  17. Interns reflect: the effect of formative assessment with feedback during pre-internship

    Directory of Open Access Journals (Sweden)

    McKenzie S

    2017-01-01

    Full Text Available Susan McKenzie,1 Annette Burgess,2 Craig Mellis1 1Central Clinical School, 2Education Office, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia Background: It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt students with “one-to-one” formative feedback on their ability to perform urethral catheterization (U/C and hypothesized that their future practice of U/C as interns would benefit. This study sought to evaluate the performance and practice of interns in U/C 4–5 months after having received feedback on their performance of U/C as PrInt students.Methods: Between 2013 and 2014, two cohorts of interns, (total n=66 who had received recent formative feedback on their U/C performance as PrInt students at Central Clinical School, were invited to complete an anonymous survey. The survey contained nine closed unvalidated questions and one open-ended question, designed to allow interns to report on their current practice of U/C.Results: Forty-one out of 66 interns (62% completed the survey. Thirty-five out of 41 respondents (85% reported that the assessment with feedback during their PrInt term was beneficial to their practice. Thirty of 41 (73% reported being confident to perform U/C independently. Eleven out of 41 respondents (27% reported that they had received additional training at intern orientation. Nine of the 11 interns (82% reported that they had a small, but a significant, increase in confidence to perform U/C when compared with the 30 of the 41 respondents (73% who had not (p=0.03.Conclusion: Our results substantiate our hypothesis that further education by assessment with feedback in U/C during PrInt was of benefit to interns’ performance. Additional educational reinforcement in U/C during intern orientation further improved intern

  18. Comparative study of trace element contents in human full-term placenta and fetal membranes by total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Kubala-Kukus, A. E-mail: aldona.kubala-kukus@pu.kielce.pl; Banas, D.; Braziewicz, J.; Majewska, U.; Pajek, M

    2003-04-18

    The total reflection X-ray fluorescence (TXRF) method was applied to study the influence of environmental pollution on the contents of trace elements in human full-term placenta and fetal membranes. The samples were collected from the donors living in two regions characterised by different levels of environmental pollution. In this comparative study, based on relatively large ({approx}100) populations, the concentrations of approximately 20 trace elements (P-Pb) were determined in the samples. In particular, the paper discusses the role of 'truncation' of measured concentration distribution by the detection limit of the TXRF method in context of comparative studies. First, the importance of the developed method of reconstruction of original concentration distribution, to derive the correct concentrations of trace elements, is described and demonstrated and, second, the statistical tests, which can be used to compare the truncated, or reconstructed, concentration distributions are discussed. Finally, the statistically significant differences of trace element concentrations found in both populations are presented and summarised.

  19. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Directory of Open Access Journals (Sweden)

    Alexander Ač

    2012-01-01

    Full Text Available We explored ability of reflectance vegetation indexes (VIs related to chlorophyll fluorescence emission (686/630, 740/800 and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as (531−570/(531−570 to track changes in the CO2 assimilation rate and Light Use Efficiency (LUE in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO2 assimilation (MAX was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ(686/630 of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to MAX (2=0.51. In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP, Net Ecosystem Exchange (NEE, and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index 686/630 with NEE and GPP.

  20. Quantification of potentially toxic elements in sewage and sludge from treatment plants in the cities of Campinas and Jaguariuna using synchrotron radiation total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Souza, Luciana Carla Ferreira de; Canteras, Felippe Benavente; Moreira, Silvana

    2013-01-01

    The rapid urban and industrial development in last decades has brought as one of the consequences, changes in the environment. The lack of planning of city growth is, today, one of the major causes of water pollution including residential, industrial, agricultural, and hospital waste. The metals contamination is a major problem, causing serious changes to the environment, causing harm to human health. The sludge generated at sewage treatment plants, is an important source of nutrients and organic matter, and therefore it can also be reused mainly for agricultural use, since contaminants are removed. The cities of Campinas and Jaguariuna are inserted in the Campinas Metropolitan Region (CMR), one of the most dynamic regions in the Brazilian economy. Therefore, to study the anthropogenic influences of the cities, evaluated the quality of raw and treated effluent and the sludge generated in sewage treatment plants, especially with regard to heavy metals. Measurements of metals were performed by Synchrotron Radiation Total Reflection X-ray Fluorescence. For treated effluent data were compared to CONAMA 357 law and Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb showed concentrations in according with the law. To reuse in agriculture the contents were compared to the limits defined by CETESB and some elements had concentrations above to the permitted preventing its reuse. For sludge, Cr, Ni, Cu, Zn, Ba and Pb, in the two treatment plants studied, the concentrations were lower than the maximum permissible values established by CONAMA 375 law allowing the sludge application sludge on agricultural land. (author)

  1. Characterization by Total Reflection X-ray Fluorescence Spectrometry of filtered water into the cave under the Sun Pyramid in Teotihuacan City

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, T. [National University of Mexico, Faculty of Chemistry, Building D, CU, O4510, Mexico, D.F. (Mexico)], E-mail: tmc@servidor.unam.mx; Zarazua, G.; Avila-Perez, P. [National Institute of Nuclear Research, Carr. Mexico-Toluca Km 36.5, 52045, Salazar, Ocoyoacac, Edo. de Mexico (Mexico); Juarez, F. [National University of Mexico, Institute of Geophysics, Circuito Institutos, CU, 04510 Mexico, D.F. (Mexico); Cabrera, L. [National University of Mexico, Faculty of Chemistry, Building D, CU, O4510, Mexico, D.F. (Mexico); Martinez, G. [Coordinacion Nacional de Conservacion del Patrimonio Cultural, Xicotencatl y General Anaya s/n., 04120, Mexico, D.F. (Mexico)

    2008-12-15

    Teotihuacan (50 km north-east Mexico City) was the most important ancient city in Mesoamerica and it flourished 200-750 AC. It is situated in the central part of the Valley of Teotihuacan, in Central Mexico. This study was carried out in the 102 m-long cave under the largest single construction, the massive Sun Pyramid, being located on the east side of the 'Avenue of the Dead', in the northern half-part of the city. The study shows the results of Total Reflection X-ray Fluorescence Spectrometry analysis and other techniques of a water sample obtained from the inside of the cave. The inside temperature ranged between 19 and 22 deg. C; relative humidity was between 98 and 99.3%; water-dropping velocity (water de-sorption capability) was 13.5 {mu}L min{sup -1}. Water samples from wells around the site were analyzed too. Metal concentration in all of the water samples matches the characteristics of the sampling site, well's depth, soil and minerals.

  2. Characterization by Total Reflection X-ray Fluorescence Spectrometry of filtered water into the cave under the Sun Pyramid in Teotihuacan City

    International Nuclear Information System (INIS)

    Martinez, T.; Zarazua, G.; Avila-Perez, P.; Juarez, F.; Cabrera, L.; Martinez, G.

    2008-01-01

    Teotihuacan (50 km north-east Mexico City) was the most important ancient city in Mesoamerica and it flourished 200-750 AC. It is situated in the central part of the Valley of Teotihuacan, in Central Mexico. This study was carried out in the 102 m-long cave under the largest single construction, the massive Sun Pyramid, being located on the east side of the 'Avenue of the Dead', in the northern half-part of the city. The study shows the results of Total Reflection X-ray Fluorescence Spectrometry analysis and other techniques of a water sample obtained from the inside of the cave. The inside temperature ranged between 19 and 22 deg. C; relative humidity was between 98 and 99.3%; water-dropping velocity (water de-sorption capability) was 13.5 μL min -1 . Water samples from wells around the site were analyzed too. Metal concentration in all of the water samples matches the characteristics of the sampling site, well's depth, soil and minerals

  3. Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Zarazua, G.; Avila-Perez, P.; Tejeda, S.; Barcelo-Quintal, I.; Martinez, T.

    2006-01-01

    The present area of study is located in the Upper Course of the Lerma River (UCLR). The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The aim of the present study is to determine the heavy metal concentration of Cr, Mn, Fe, Cu and Pb in dissolved and total phases of the UCLR by means of Total Reflection X-ray Fluorescence Spectrometry (TXRF). The surface water samples were collected at 8 sites distributed following the stream flow direction of the river. Four sampling campaigns were carried out in each site in a 1-year period. A sample preparation method was applied in order to obtain the total and dissolved fraction and to destroy the organic matter. The total heavy metal average concentration decrease in the following order: Fe (2566 μg/L) > Mn (300 μg/L) > Cu (66 μg/L) > Cr (21 μg/L) > Pb (15 μg/L). In general, the heavy metal concentrations in water of the UCLR are below the maximum permissible limits

  4. Total reflection X-ray fluorescence measurements of S and P in proteins using a vacuum chamber specially designed for low Z elements

    International Nuclear Information System (INIS)

    Rauwolf, M.; Vanhoof, C.; Tirez, K.; Maes, E.; Ingerle, D.; Wobrauschek, P.; Streli, C.

    2014-01-01

    As the ratio of phosphorus and sulfur in proteins allows the determination of the phosphorylation degree in proteins, the absolute determination of phosphorus and sulfur in organic samples is of growing interest. While it takes some effort to quantify phosphorus and sulfur with inductively coupled quadrupole plasma mass spectrometry (ICP-QMS), total reflection X-ray fluorescence analysis (TXRF) allows easy quantification. In the presented work, the low Z TXRF spectrometer at the Atominstitut was used to analyze phosphorus and sulfur in proteins. Although the preparation of the protein samples proved to be more difficult than originally expected, it could be shown that TXRF is well suited for the determination of P and S in proteins. The obtained lower limits of detection (LLD) for P and S in proteins were extrapolated for 1000s and were 34 pg and 19 pg, respectively. The importance of height scans for each sample to exclude heterogeneities was demonstrated. - Highlights: • Low Z TXRF spectrometry was used to analyze phosphorus and sulfur in proteins. • TXRF is well suited for the determination of P and S in proteins. • Good detection limits for P (34 pg) and S (19 pg) were achieved. • Due to the detection limits, we propose that TXRF is a suitable method to analyze protein fractions

  5. Analysis of heavy metals and minerals elements in the turmeric using Total-Reflection X-ray Fluorescence analysis technique and Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    Andriamisetra, V.M.Z.

    2014-01-01

    Currently, many studies demonstrate anti-cancer and anti-inflammatory benefits of turmeric. The aims of this work is to perform analysis of metals such as calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, bromine, rubidium, strontium, cadmium and lead in the turmeric collected from various places in Madagascar. The analysis by total reflection X-ray fluorescence technique is used to determine the concentrations of heavy metals, while the atomic absorption spectrometry is used for the determination of trace elements. Analysis results show that the concentration of calcium in the turmeric is very high, its average concentration is 1025.8 mg.kg -1 . The average concentrations of manganese, of copper and of iron are respectively 44.7 mg.kg -1 ; 19.7 mg.kg -1 and 53.6 mg.kg -1 . The average concentrations of zinc, of rubidium and of strontium are respectively 17.3 mg.kg -1 ; 35.2 mg.kg -1 and 21.7 mg.kg -1 [fr

  6. Headspace thin-film microextraction onto graphene membranes for specific detection of methyl(cyclopentadienyl)-tricarbonyl manganese in water samples by total reflection X-ray fluorescence

    Science.gov (United States)

    Romero, V.; Costas-Mora, I.; Lavilla, I.; Bendicho, C.

    2016-12-01

    In this work, a novel analytical approach for determining methyl(cyclopentadienyl)-tricarbonyl (MMT) by total reflection X-ray fluorescence (TXRF) based on its trapping onto unmodified graphene membranes is described. Graphene membranes were synthesized by mild-thermal reduction of graphene oxide following drop-casting onto a glass substrate. High flexible and easy-to-handle graphene membranes with 10 mm diameter were obtained. In order to use the as-prepared membranes as extraction phases for headspace thin-solid film microextraction of MMT, they were fitted to quartz reflectors and placed onto the top of the glass vial containing the sample. Reflectors containing graphene membranes were directly used as sample carriers for TXRF analysis. Different parameters involved in the microextraction step were optimized in order to obtain the best performance. Detection and quantification limits were 18 and 60 ng L- 1 MMT, respectively. An enrichment factor of 265 was obtained. The method was successfully applied for the specific detection of MMT in different water samples and a certified reference material e.g., NWTM-27.2 fortified lake water. A recovery study was carried out on spiked water samples showing recoveries in the range 98-104% with a relative standard deviation of 4% (N = 5). In addition, speciation of manganese, i.e. MMT and Mn(II),in water samples can be accomplished since only volatile MMT is transferred to the headspace and retained onto graphene membranes.

  7. Ultrasound-assisted single extraction tests for rapid assessment of metal extractability from soils by total reflection X-ray fluorescence.

    Science.gov (United States)

    De La Calle, I; Cabaleiro, N; Lavilla, I; Bendicho, C

    2013-09-15

    In this work, ultrasound-assisted extraction (UAE) was employed for acceleration of metal extraction from soil samples. After extraction, multielemental analysis (Cr, Mn, Fe, Ni, Cu, Zn and Pb) of EDTA and acetic acid extracts was performed by total reflection X-ray fluorescence spectrometry (TXRF). High-intensity ultrasonic processors, i.e. the ultrasonic probe (50W) and the cup-horn sonoreactor (200W) were applied. Both ultrasonic procedures were compared with a miniaturized version of the single extraction scheme proposed by the Standards, Measurements and Testing program (SM&T). The extraction time with EDTA was reduced from 1h (conventional procedure) to 2 min (ultrasonic probe) or to 10 min (cup-horn sonoreactor). The time required for acetic acid extraction was also reduced from 16 h (conventional procedure) to 6 min (ultrasonic probe) or to 30 min (cup-horn sonoreactor). In addition, the amount of sample and extractants was drastically reduced as a result of the miniaturization implemented in the developed approaches. The combination of UAE and TXRF allows assessing the potential metal mobility and bioavailability in a simple way. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Determination of trace elements in planktonic microcrustaceans using total reflection X-ray fluorescence (TXRF): First results from two Chilean lakes

    Energy Technology Data Exchange (ETDEWEB)

    Woelfl, Stefan; Mercado, Susana; Villalobos, Lorena [Instituto de Zoologia, Universidad Austral de Chile, Casilla 567, Valdivia (Chile); Mages, Margarete; Ovari, Mihaly [Department of Inland Water Research Magdeburg, UFZ Centre for Environmental Research Leipzig-Halle, Brueckstrasse 3a, 39114, Magdeburg (Germany); Encina, Francisco [Escuela de Ciencias Ambientales, Facultad de Ciencias, Universidad Catolica de Temuco, Montt 056, Temuco (Chile)

    2004-02-01

    First results are described from the application of a recently developed dry method for determination of elements in single specimens of freshwater microcrustaceans, using total reflection X-ray fluorescence spectrometry (TXRF). This method is a powerful, non-destructive technique for quantifying the trace element content of minute biological samples with a dry weight of 3-50 {mu}g. Three different freshwater microcrustaceans were sampled, from the natural, uncontaminated Lake Laja and from the artificial Rapel reservoir which is slightly contaminated by drainage water from a copper mine. Single specimens of Daphnia pulex, Bosmina chilensis, and Ceriodaphnia dubia were prepared using a modification of the dry method and measured by TXRF. The results showed that both As, Mn, Fe, Ni, Zn, and Cu content and the bioaccumulation of these metals were usually significantly different between the microcrustaceans from the two lakes. The largest difference was found for Cu which was eight times more concentrated in the two microcrustaceans from Rapel reservoir than it was in D. pulex from Lake Laja. (orig.)

  9. Use of total reflection X-ray fluorescence to determine micro- and macroelements in the plasma of animals parasitized by Tripanossoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Zucchi, Orgheda L.A. Domingues [Universidade de Sao Paulo, Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Fisica e Quimica]. E-mail: Batista, Fernanda Ap. H.; Albuquerque, Sergio de [Universidade de Sao Paulo, Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Analises Clinicas, Bromatologica e Toxicologica]. E-mail: fer_usp@yahoo.com.br; sdalbuque@fcfrp.usp.br; Nascimento Filho, Virgilio F. [Centro de Energia Nuclear na Agricultura CENA, Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2007-07-01

    The mineral levels of S, Cl, K, Ca, Cr, Fe, Cu, and Zn in the plasma of mice (line BALB/c) infected with strains Bolivia and Y of Trypanosoma cruzi were determined by Total Reflection X-Ray Fluorescence technique (TXRF), with concentration raging from 0.2 (Cu) to 2650 (S) {mu}g/g. Three experimental groups were used: a control group, a group of infected females, and a group of infected males. The plasma of the animals was obtained before, during, and after the parasitemic peak for each of the three groups and for each strain used. Sample excitation was performed using an X-ray tube with a Mo target and Zr filter, operating at 40 kV and 30 mA, at an incidence angle of 6.4 min. In general, the elements evaluated showed small variations between the different groups, without statistical difference. Significant alterations were observed in the Bolivia strain, demonstrating that a relation between this strain and changes in the levels determined for the elements might exist. (author)

  10. Study on trace elements behaviour in cancerous and healthy tissues of colon, breast and stomach: Total reflection X-ray fluorescence applications

    Science.gov (United States)

    Magalhães, T.; Carvalho, M. L.; Von Bohlen, A.; Becker, M.

    2010-06-01

    In this work Total-reflection X-ray fluorescence (TXRF) was used to analyse healthy and cancerous tissues of the same individual along several contiguous thin sections of each tissue. Thirty two samples (16 pairs) of breast tissue, 30 samples (15 pairs) of intestine tissue and 10 samples (5 pairs) of stomach tissue were analysed. The samples were obtained in Civil Hospitals of Germany (Dortmund) and Portugal (Lisbon). The elemental distribution of P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr and Pb in these samples was studied. Descriptive statistics based on bar graphics and hypotheses tests and also an automatic classification based on hierarchical grouping analysis was used for the several analysed tissues. It was shown that the behaviour of the elements is tissue dependent. Some elements, like P and K exhibit the same behaviour in all the analysed tissue types. They have increased concentrations in all cancerous tissues. Unlike, other elements like Br show completely different behaviour depending on the tissue: similar concentration in healthy and cancerous stomach, decreased levels in colon cancerous tissues and enhanced concentrations in breast was observed. Moreover cancer tissues present decreased Se concentrations on colon and increased on breast.

  11. Parameter study of self-absorption effects in Total Reflection X-ray Fluorescence-X-ray Absorption Near Edge Structure analysis of arsenic

    International Nuclear Information System (INIS)

    Meirer, F.; Pepponi, G.; Streli, C.; Wobrauschek, P.; Kregsamer, P.; Zoeger, N.; Falkenberg, G.

    2008-01-01

    Total reflection X-ray Fluorescence (TXRF) analysis in combination with X-ray Absorption Near Edge Structure (XANES) analysis is a powerful method to perform chemical speciation studies at trace element levels. However, when measuring samples with higher concentrations and in particular standards, damping of the oscillations is observed. In this study the influence of self-absorption effects on TXRF-XANES measurements was investigated by comparing measurements with theoretical calculations. As(V) standard solutions were prepared at various concentrations and dried on flat substrates. The measurements showed a correlation between the damping of the oscillations and the As mass deposited. A Monte-Carlo simulation was developed using data of the samples shapes obtained from confocal white light microscopy. The results showed good agreement with the measurements; they confirmed that the key parameters are the density of the investigated atom in the dried residues and the shape of the residue, parameters that combined define the total mass crossed by a certain portion of the incident beam. The study presents a simple approach for an a priori evaluation of the self-absorption in TXRF X-ray absorption studies. The consequences for Extended X-ray Absorption Fine Structure (EXAFS) and XANES measurements under grazing incidence conditions are discussed, leading to the conclusion that the damping of the oscillations seems to make EXAFS of concentrated samples non feasible. For XANES 'fingerprint' analysis samples should be prepared with a deposited mass and sample shape leading to an acceptable absorption for the actual investigation

  12. Seasonal determination of trace and ultra-trace content in Macrocystis pyrifera from San Jorge Gulf (Patagonia) by Total Reflection X-ray Fluorescence

    Science.gov (United States)

    Salomone, Vanesa N.; Riera, Marina; Cerchietti, Luciana; Custo, Graciela; Muniain, Claudia

    2017-05-01

    Seaweed have a great capacity to accumulate heavy metals in their tissues. The chemical characterization of seaweed is important due to their use in environmental monitoring and human or animal food. The aim of the present study was to evaluate the multi-elemental composition of seaweed from San Jorge Gulf (Patagonia, Argentina) by Total Reflection X-ray Fluorescence (TXRF). The elements As, Br, Cu, Cr, Fe, Mn, Ni, Pb, Rb, Sr, V and Zn were seasonally analyzed and quantified in blades of Macrocystis pyrifera. TXRF showed to be a suitable technique for simultaneous multi-element analysis in this kind of samples. The results revealed seasonal variations in the chemical content for some elements; arsenic content was maximum in summer and autumn, iron concentration increased to the winter and zinc concentration was maximum in autumn. The sum of principal micronutrients (Fe + Zn + Mn + Cu) varied between 114 and 171 mg k- 1 g dw. The total As concentration ranged between 36 and 66 mg kg- 1. Lead, nickel and copper were not detected.

  13. Direct Determination of Oxidation States of Uranium in Mixed-Valent Uranium Oxides Using Total Reflection X-ray Fluorescence X-ray Absorption Near-Edge Spectroscopy.

    Science.gov (United States)

    Sanyal, Kaushik; Khooha, Ajay; Das, Gangadhar; Tiwari, M K; Misra, N L

    2017-01-03

    Total reflection X-ray fluorescence (TXRF)-based X-ray absorption near-edge spectroscopy has been used to determine the oxidation state of uranium in mixed-valent U 3 O 8 and U 3 O 7 uranium oxides. The TXRF spectra of the compounds were measured using variable X-ray energies in the vicinity of the U L 3 edge in the TXRF excitation mode at the microfocus beamline of the Indus-2 synchrotron facility. The TXRF-based X-ray absorption near-edge spectroscopy (TXRF-XANES) spectra were deduced from the emission spectra measured using the energies below and above the U L 3 edge in the XANES region. The data processing using TXRF-XANES spectra of U(IV), U(V), and U(VI) standard compounds revealed that U present in U 3 O 8 is a mixture of U(V) and U(VI), whereas U in U 3 O 7 is mixture of U(IV) and U(VI). The results obtained in this study are similar to that reported in literature using the U M edge. The present study has demonstrated the possibility of application of TXRF for the oxidation state determination and elemental speciation of radioactive substances in a nondestructive manner with very small amount of sample requirement.

  14. Simple and rapid quantification of gadolinium in urine and blood plasma samples by means of total reflection X-ray fluorescence (TXRF).

    Science.gov (United States)

    Telgmann, Lena; Holtkamp, Michael; Künnemeyer, Jens; Gelhard, Carsten; Hartmann, Marcel; Klose, Annika; Sperling, Michael; Karst, Uwe

    2011-10-01

    A simple and rapid method to determine gadolinium (Gd) concentrations in urine and blood plasma samples by means of total reflection X-ray fluorescence (TXRF) was developed. With a limit of detection (LOD) of 100 μg L(-1) in urine and 80 μg L(-1) in blood plasma and a limit of quantification (LOQ) of 330 μg L(-1) in urine and 270 μg L(-1) in blood plasma, it allows analyzing urine samples taken from magnetic resonance imaging (MRI) patients during a period of up to 20 hours after the administration of Gd-based MRI contrast agents by means of TXRF. By parallel determination of the urinary creatinine concentration, it was possible to monitor the excretion kinetics of Gd from the patient's body. The Gd concentration in blood plasma samples, taken immediately after an MRI examination, could be determined after rapid and easy sample preparation by centrifugation. All measurements were validated with inductively coupled plasma mass spectrometry (ICP-MS). TXRF is considered to be an attractive alternative for fast and simple Gd analysis in human body fluids during daily routine in clinical laboratories. This journal is © The Royal Society of Chemistry 2011

  15. Determination of trace elements in planktonic microcrustaceans using total reflection X-ray fluorescence (TXRF): first results from two Chilean lakes.

    Science.gov (United States)

    Woelfl, Stefan; Mages, Margarete; Mercado, Susana; Villalobos, Lorena; Ovári, Mihály; Encina, Francisco

    2004-02-01

    First results are described from the application of a recently developed dry method for determination of elements in single specimens of freshwater microcrustaceans, using total reflection X-ray fluorescence spectrometry (TXRF). This method is a powerful, non-destructive technique for quantifying the trace element content of minute biological samples with a dry weight of 3-50 microg. Three different freshwater microcrustaceans were sampled, from the natural, uncontaminated Lake Laja and from the artificial Rapel reservoir which is slightly contaminated by drainage water from a copper mine. Single specimens of Daphnia pulex, Bosmina chilensis, and Ceriodaphnia dubia were prepared using a modification of the dry method and measured by TXRF. The results showed that both As, Mn, Fe, Ni, Zn, and Cu content and the bioaccumulation of these metals were usually significantly different between the microcrustaceans from the two lakes. The largest difference was found for Cu which was eight times more concentrated in the two microcrustaceans from Rapel reservoir than it was in D. pulex from Lake Laja.

  16. Iron speciation in human cancer cells by K-edge total reflection X-ray fluorescence-X-ray absorption near edge structure analysis

    Energy Technology Data Exchange (ETDEWEB)

    Polgari, Zs. [Eoetvoes Lorand University, Institute of Chemistry, Department of Analytical Chemistry, Laboratory of Environmental Chemistry and Bioanalytics, P.O. Box 32, H-1518, Budapest (Hungary); Meirer, F. [Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna (Austria); MiNALab, CMM-irst, Fondazione Bruno Kessler, Povo, Trento (Italy); Sasamori, S.; Ingerle, D. [Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna (Austria); Pepponi, G. [MiNALab, CMM-irst, Fondazione Bruno Kessler, Povo, Trento (Italy); Streli, C. [Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna (Austria); Rickers, K. [Hamburger Synchrotronstrahlungslabor at DESY, Hamburg (Germany); Reti, A.; Budai, B. [Department of Clinical Research, National Institute of Oncology, Budapest (Hungary); Szoboszlai, N. [Eoetvoes Lorand University, Institute of Chemistry, Department of Analytical Chemistry, Laboratory of Environmental Chemistry and Bioanalytics, P.O. Box 32, H-1518, Budapest (Hungary); Zaray, G., E-mail: zaray@ludens.elte.hu [Eoetvoes Lorand University, Institute of Chemistry, Department of Analytical Chemistry, Laboratory of Environmental Chemistry and Bioanalytics, P.O. Box 32, H-1518, Budapest (Hungary)

    2011-03-15

    X-ray absorption near edge structure (XANES) analysis in combination with synchrotron radiation induced total reflection X-ray fluorescence (SR-TXRF) acquisition was used to determine the oxidation state of Fe in human cancer cells and simultaneously their elemental composition by applying a simple sample preparation procedure consisting of pipetting the cell suspension onto the quartz reflectors. XANES spectra of several inorganic and organic iron compounds were recorded and compared to that of different cell lines. The XANES spectra of cells, independently from the phase of cell growth and cell type were very similar to that of ferritin, the main Fe store within the cell. The spectra obtained after CoCl{sub 2} or NiCl{sub 2} treatment, which could mimic a hypoxic state of cells, did not differ noticeably from that of the ferritin standard. After 5-fluorouracil administration, which could also induce an oxidative-stress in cells, the absorption edge position was shifted toward higher energies representing a higher oxidation state of Fe. Intense treatment with antimycin A, which inhibits electron transfer in the respiratory chain, resulted in minor changes in the spectrum, resembling rather the N-donor Fe-{alpha},{alpha}'-dipyridyl complex at the oxidation energy of Fe(III), than ferritin. The incorporation of Co and Ni in the cells was followed by SR-TXRF measurements.

  17. Effect of modulation of the particle size distributions in the direct solid analysis by total-reflection X-ray fluorescence

    Science.gov (United States)

    Fernández-Ruiz, Ramón; Friedrich K., E. Josue; Redrejo, M. J.

    2018-02-01

    The main goal of this work was to investigate, in a systematic way, the influence of the controlled modulation of the particle size distribution of a representative solid sample with respect to the more relevant analytical parameters of the Direct Solid Analysis (DSA) by Total-reflection X-Ray Fluorescence (TXRF) quantitative method. In particular, accuracy, uncertainty, linearity and detection limits were correlated with the main parameters of their size distributions for the following elements; Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb. In all cases strong correlations were finded. The main conclusion of this work can be resumed as follows; the modulation of particles shape to lower average sizes next to a minimization of the width of particle size distributions, produce a strong increment of accuracy, minimization of uncertainties and limit of detections for DSA-TXRF methodology. These achievements allow the future use of the DSA-TXRF analytical methodology for development of ISO norms and standardized protocols for the direct analysis of solids by mean of TXRF.

  18. Evaluation of bioaccumulation kinetics of gold nanorods in vital mammalian organs by means of total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Fernández-Ruiz, Ramón; Redrejo, María Jesús; Friedrich, Eberhardt Josué; Ramos, Milagros; Fernández, Tamara

    2014-08-05

    This work presents the first application of total-reflection X-ray fluorescence (TXRF) spectrometry, a new and powerful alternative analytical method, to evaluation of the bioaccumulation kinetics of gold nanorods (GNRs) in various tissues upon intravenous administration in mice. The analytical parameters for developed methodology by TXRF were evaluated by means of the parallel analysis of bovine liver certified reference material samples (BCR-185R) doped with 10 μg/g gold. The average values (n = 5) achieved for gold measurements in lyophilized tissue weight were as follows: recovery 99.7%, expanded uncertainty (k = 2) 7%, repeatability 1.7%, detection limit 112 ng/g, and quantification limit 370 ng/g. The GNR bioaccumulation kinetics was analyzed in several vital mammalian organs such as liver, spleen, brain, and lung at different times. Additionally, urine samples were analyzed to study the kinetics of elimination of the GNRs by this excretion route. The main achievement was clearly differentiating two kinds of behaviors. GNRs were quickly bioaccumulated by highly vascular filtration organs such as liver and spleen, while GNRs do not show a bioaccumulation rates in brain and lung for the period of time investigated. In parallel, urine also shows a lack of GNR accumulation. TXRF has proven to be a powerful, versatile, and precise analytical technique for the evaluation of GNRs content in biological systems and, in a more general way, for any kind of metallic nanoparticles.

  19. Total reflection X-ray fluorescence measurements of S and P in proteins using a vacuum chamber specially designed for low Z elements

    Energy Technology Data Exchange (ETDEWEB)

    Rauwolf, M., E-mail: mrauwolf@ati.ac.at [Atominstitut, Technische Universität Wien, Stadionallee 2, Vienna 1020 (Austria); Vanhoof, C.; Tirez, K.; Maes, E. [Flemish Institute for Technological Research NV, Boeretang 200, Mol 2400 (Belgium); Ingerle, D.; Wobrauschek, P.; Streli, C. [Atominstitut, Technische Universität Wien, Stadionallee 2, Vienna 1020 (Austria)

    2014-11-01

    As the ratio of phosphorus and sulfur in proteins allows the determination of the phosphorylation degree in proteins, the absolute determination of phosphorus and sulfur in organic samples is of growing interest. While it takes some effort to quantify phosphorus and sulfur with inductively coupled quadrupole plasma mass spectrometry (ICP-QMS), total reflection X-ray fluorescence analysis (TXRF) allows easy quantification. In the presented work, the low Z TXRF spectrometer at the Atominstitut was used to analyze phosphorus and sulfur in proteins. Although the preparation of the protein samples proved to be more difficult than originally expected, it could be shown that TXRF is well suited for the determination of P and S in proteins. The obtained lower limits of detection (LLD) for P and S in proteins were extrapolated for 1000s and were 34 pg and 19 pg, respectively. The importance of height scans for each sample to exclude heterogeneities was demonstrated. - Highlights: • Low Z TXRF spectrometry was used to analyze phosphorus and sulfur in proteins. • TXRF is well suited for the determination of P and S in proteins. • Good detection limits for P (34 pg) and S (19 pg) were achieved. • Due to the detection limits, we propose that TXRF is a suitable method to analyze protein fractions.

  20. Room temperature trapping of stibine and bismuthine onto quartz substrates coated with nanostructured palladium for total reflection X-ray fluorescence analysis

    Science.gov (United States)

    Romero, Vanesa; Costas-Mora, Isabel; Lavilla, Isela; Bendicho, Carlos

    2015-05-01

    In this work, a novel method for determining Sb and Bi based on the trapping of their covalent hydrides onto quartz reflectors coated with immobilized palladium nanoparticles (Pd NPs) followed by total reflection X-ray fluorescence (TXRF) analysis is proposed. Pd NPs were synthesized by chemical reduction of the metal precursor using a mixture of water:ethanol as mild reducing agent. Silanization using 3-mercaptopropyltrimethoxysilane (MPTMS) was performed for the immobilization of Pd NPs onto the quartz substrates. Volatile hydrides (stibine and bismuthine) generated by means of a continuous flow system were flushed onto the immobilized Pd NPs and retained by catalytic decomposition. As a result of the high catalytic activity of the nanostructured film, trapping can be performed at ambient temperature with good efficiency. Limits of detection (LODs) were 2.3 and 0.70 μg L- 1 for Sb and Bi, respectively. Enrichment factors of 534 and 192 were obtained for Sb and Bi, respectively. The new method was applied for the analysis of several matrices (milk, soil, sediment, cutaneous powder). Recoveries were in the range of 98.4-101% for both elements with a relative standard deviation of 2.5% (N = 5).

  1. Determination of nickel, copper, zinc and lead in human scalp hair in Syrian occupationally exposed workers by total reflection X-ray fluorescence.

    Science.gov (United States)

    Khuder, A; Bakir, M A; Hasan, R; Mohammad, A

    2008-08-01

    The concentrations of Ni, Cu, Zn, and Pb in human scalp hair of 281 individuals working in 10 Syrian industrial plants were determined using co-precipitation by ammoniumpyrolidinedithiocarbamate (APDC) method for total reflection X-ray fluorescence (TXRF) analysis. The results were compared to data obtained for a control group consisted of individuals working at the Syrian Atomic Energy Commission and also to data reported in the literature. The results given by the group of workers in battery plant showed that Pb concentration in human scalp hair samples were higher than those for control group, while some abnormal concentrations were obtained for Cu, Zn and Ni in cables, printing and battery plants, respectively. Normal concentrations of these elements were obtained for hair workers in olive oil, power stations, textile, and iron industrial plants. The relationships of Pb-Pb/Ni and Cu-Cu/Ni were plotted with correlation coefficients of 0.9937 and 0.9014, respectively. In general, the results showed that, the workers who were occupationally exposed to battery industrial pollution are at risk, followed by individuals in printing and cables industries, while the rest of workers in other industries are considered occupationally unexposed.

  2. Determination of element distribution between the symplasm and apoplasm of cucumber plant parts by total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Varga, Anita; Záray, Gyula; Fodor, Ferenc

    2002-04-10

    The distribution of Cd, Ni, Pb and Fe between the symplasm (cytoplasm) and apoplasm (cell wall) of cucumber roots and leaves was determined by total reflection X-ray fluorescence spectrometry following a special sample preparation procedure. The plants were grown in modified Hoagland nutrient solution containing Fe in chemical form of Fe(III)-citrate or Fe(III)-EDTA, as well as the heavy metal contaminants, each in concentration of 10 microM. In the roots the larger part of Pb was found in the apoplasm, while Ni and Cd were mostly in the symplasm. In the leaves however, about 50-60% of the Pb content and practically the total amount of Cd were detected in the symplasm. About 30-40% of the translocated Ni remained in the apoplasm of the leaves. The Cd-, Ni- and Pb-treatments resulted in higher total concentration of Fe in the roots, however, the relative amount of Fe in the symplasm decreased in all cases. In the leaves of the control plants the larger part (60-80%) of Fe occurs in the symplasm. Due to the heavy metal effects, the relative amount of Fe in the symplasm decreased except in the Pb-contaminated plants, where in the presence of Fe(III)-EDTA, the Pb treatment resulted in a moderate increment of Fe concentration in the symplasm.

  3. Biofilms as bio-indicator for polluted waters? Total reflection X-ray fluorescence analysis of biofilms of the Tisza river (Hungary).

    Science.gov (United States)

    Mages, Margarete; Ovári, Mihály; von Tümpling, Wolf; Kröpfl, Krisztina

    2004-02-01

    The aim of this work was to investigate the heavy metal accumulation by natural biofilms living in the catchment area of the Tisza river in Hungary, as well as in biofilms cultivated in vitro. Laboratory tests have demonstrated that metals can be adsorbed on biofilms, depending on their concentration and on the availability of free sorptive places. Biofilms were cultivated in vitro in natural freshwater from the Saale river, Germany. After reaching the plateau phase, Cu was added to reach a concentration of 100 micro g/L. An increase of its mass fraction in the biofilm was observed, which caused the decrease of the concentration in the water phase. Unfortunately, the reactor wall was also found to act as adsorbent for Cu. More detailed results of our in vitro experiments will be published in a forthcoming paper. Naturally grown biofilm samples from exposed as well as background places at the Hungarian rivers Szamos and Tisza were collected in 2000 and 2002 after the cyanide spill, and analysed using total reflection X-ray fluorescence analysis (TXRF). Metal mass fraction differences as high as two orders of magnitude were found between polluted and unpolluted (background) sampling points. Extremely high concentration values, e.g. 5600 microg/g Zn in biofilm, were found at highly polluted sampling points. This means an enrichment factor of ca. 10,000 compared to the water phase.

  4. Reflections on Teaching Research Ethics in Education for International Postgraduate Students in the UK

    Science.gov (United States)

    Smith, Jan

    2016-01-01

    Research ethics in education is a challenging topic to teach and to learn. As the staff and student body in UK higher education and elsewhere diversifies, the challenges increase as shared reference points diminish. My teaching reflections focus on a key tension explored in this article: how the imperative of internationalising the curriculum…

  5. Comparative Education and Research Capacity Building: Reflections on International Transfer and the Significance of Context

    Directory of Open Access Journals (Sweden)

    Michael Crossley

    2012-04-01

    Full Text Available Recent years have seen a resurgence of interest in comparative and international education, along with a fundamental reconceptualisation of this distinctive multidisciplinary field of study. The nature and significance of these developments are explored with particular reference to their implications for broader research capacity building initiatives worldwide. In doing so, a critique of the international transfer of globally dominant research modalities and strategies is presented--along with arguments for increased attention to context sensitivity in both international development cooperation and educational research in general. Illustrative examples that support these arguments are drawn from the author's own research, from an analysis of emergent educational policy debates in the UK, and from related studies being carried out in Malaysia. In concluding, the strategic role of comparative research traditions and perspectives in a rapidly globalizing world is highlighted, while supporting the promotion of new initiative and research centres for comparative and international education.

  6. Reflections between CSR and international human rights in EU initiatives for a competitive inclusive society

    DEFF Research Database (Denmark)

    Buhmann, Karin

    : The paper aims to contribute to our understanding of whether a shift is taking place in societal attitudes towards a perception that corporations have duties based on international law. This is assessed on the basis of EU initiatives on inclusiveness and responsible competitiveness, particularly...... the EU Multistakeholder Forum and the Lisbon Strategy, with a particular focus on goals or views related to the human rights of non-discrimination and rights to work, education and vocational training, and network governance in (soft) law creation. It is found that despite obvious links, international...... law does not serve as a clear source of inclusiveness or responsible competitiveness. It is also found that the initiatives assessed do not indicate a shift at EU institutional level towards a perception that business holds duties under international law. International law seems at the most to be seen...

  7. Troubling Metaphors and International Student Adjustment: Reflections from a Transnational Place

    OpenAIRE

    David Starr-Glass

    2017-01-01

    On many campuses, offices of International Student Affairs address the perceived needs of international students. However, a number of underlying assumptions and persistent metaphors shape these efforts and influence their outcomes. All students are uniquely different and face equally different challenges in adjusting to higher education. Labeling students “international” may make institutional sense, but it can potentially hinder their transition, adjustment, and ultimate success. Applying r...

  8. Determination of trace amounts of hexavalent chromium in drinking waters by dispersive microsolid-phase extraction using modified multiwalled carbon nanotubes combined with total reflection X-ray fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bahadir, Z. [Department of Chemistry, Giresun University, Giresun (Turkey); Bulut, V.N. [Macka Vocational School, Karadeniz Technical University, Macka, Trabzon (Turkey); Hidalgo, M. [Department of Chemistry, Faculty of Sciences, University of Girona, Girona (Spain); Soylak, M. [Department of Chemistry, Faculty of Sciences, Erciyes University, Kayseri (Turkey); Marguí, E., E-mail: eva.margui@udg.edu [Department of Chemistry, Faculty of Sciences, University of Girona, Girona (Spain)

    2015-05-01

    A methodology based on the combination of dispersive microsolid-phase extraction (DMSPE) with total reflection X-ray fluorescence (TXRF) spectrometry is proposed for the determination of hexavalent chromium in drinking waters. Multiwalled carbon nanotubes (MWCNTs) modified with the anionic exchanger tricaprylmethylammonium chloride (Aliquat 336) were used as solid sorbents. After the sorption process of Cr(VI) on the modified MWCNTs, the aqueous sample was separated by centrifugation and the loaded MWCNTs were suspended using a small volume of an internal standard solution and analyzed directly by a benchtop TXRF spectrometer, without any elution step. Parameters affecting the extraction process (pH and volume of the aqueous sample, amount of MWCNTs, extraction time) and TXRF analysis (volume of internal standard, volume of deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cr(VI) at trace levels. Using the best analytical conditions, it was found that the minimum Cr(VI) content that can be detected in an aqueous solution was 3 μg L{sup −1}. This value is almost 20 times lower than the maximum hexavalent chromium content permissible in drinking waters, according to the World Health Organization (WHO). Recoveries for spiked tap and mineral water samples were, in most cases, in the range of 101–108% which demonstrates the suitability of the TXRF methodology for monitoring Cr(VI) at trace levels in drinking water samples. - Highlights: • A method using DMSPE and TXRF is proposed for Cr(VI) determination in water. • CNTs modified with a commercial anionic exchanger are used for the DMSPE. • The detection limit for hexavalent chromium is 3 μg L{sup −1}. • Accuracy and precision are suitable for the analysis of tap and mineral waters.

  9. Predicting Key Agronomic Soil Properties with UV-Vis Fluorescence Measurements Combined with Vis-NIR-SWIR Reflectance Spectroscopy: A Farm-Scale Study in a Mediterranean Viticultural Agroecosystem

    Directory of Open Access Journals (Sweden)

    Emmanuelle Vaudour

    2018-04-01

    Full Text Available For adequate crop and soil management, rapid and accurate techniques for monitoring soil properties are particularly important when a farmer starts up his activities and needs a diagnosis of his cultivated fields. This study aimed to evaluate the potential of fluorescence measured directly on 146 whole soil solid samples, for predicting key soil properties at the scale of a 6 ha Mediterranean wine estate with contrasting soils. UV-Vis fluorescence measurements were carried out in conjunction with reflectance measurements in the Vis-NIR-SWIR range. Combining PLSR predictions from Vis-NIR-SWIR reflectance spectra and from a set of fluorescence signals enabled us to improve the power of prediction of a number of key agronomic soil properties including SOC, Ntot, CaCO3, iron, fine particle-sizes (clay, fine silt, fine sand, CEC, pH and exchangeable Ca2+ with cross-validation RPD ≥ 2 and R² ≥ 0.75, while exchangeable K+, Na+, Mg2+, coarse silt and coarse sand contents were fairly predicted (1.42 ≤ RPD < 2 and 0.54 ≤ R² < 0.75. Predictions of SOC, Ntot, CaCO3, iron contents, and pH were still good (RPD ≥ 1.8, R² ≥ 0.68 when using a single fluorescence signal or index such as SFR_R or FERARI, highlighting the unexpected importance of red excitations and indices derived from plant studies. The predictive ability of single fluorescence indices or original signals was very significant for topsoil: this is very important for a farmer who wishes to update information on soil nutrient for the purpose of fertility diagnosis and particularly nitrogen fertilization. These results open encouraging perspectives for using miniaturized fluorescence devices enabling red excitation coupled with red or far-red fluorescence emissions directly in the field.

  10. Access to health care as a human right in international policy: critical reflections and contemporary challenges.

    Science.gov (United States)

    Castillo, Camilo Hernán Manchola; Garrafa, Volnei; Cunha, Thiago; Hellmann, Fernando

    2017-07-01

    Using the United Nations (UN) and its subordinate body, the World Health Organization (WHO), as a frame of reference, this article explores access to healthcare as a human right in international intergovernmental policies. First, we look at how the theme of health is treated within the UN, focusing on the concept of global health. We then discuss the concept of global health from a human rights perspective and go on to outline the debate surrounding universal coverage versus universal access as a human right, addressing some important ethical questions. Thereafter, we discuss universal coverage versus universal access using the critical and constructivist theories of international relations as a frame of reference. Finally, it is concluded that, faced with the persistence of huge global health inequalities, the WHO began to reshape itself, leaving behind the notion of health as a human right and imposing the challenge of reducing the wide gap that separates international intergovernmental laws from reality.

  11. International migration and the global agenda: reflections on the 1998 UN Technical Symposium.

    Science.gov (United States)

    Castles, S

    1999-01-01

    This article reviews the nature of discussions at the 1998 UN Technical Symposium on International Migration and Development. The Symposium reviewed the literature linking migration and development and successful policy approaches. Several themes emerged. A research framework is needed for accounting for all types of population mobility at all stages of the migratory process. Research should integrate contributions from a range of disciplines. The influence of social networks and cultural capital has grown in importance. Strategies need to account for women's experiences, which involve both empowerment and exploitation. Strategies need to consider return migration and better public information on migration and settlement. It was agreed that there is a need for a variety of quantitative and qualitative approaches and multidimensional analysis. The links between migration and development are complex, but sufficient information is available to greatly improve policy formation and international cooperation. National level responses have occasionally eroded the rights and protection of migrants. Few countries have adopted the 1990 UN Convention on the Rights of Migrant Workers and their Families and ILO Conventions 97 and 143. A prominent realization was that international cooperation did matter. International migration should be viewed as an opportunity for cooperation and development.

  12. Improving adolescent sexual and reproductive health in Latin America: reflections from an International Congress

    NARCIS (Netherlands)

    Córdova Pozo, K.; Chandra-Mouli, V.; Decat, P.; Nelson, E.; de Meyer, S.; Jaruseviciene, L.; Vega, B.; Segura, Z.; Auquilla, N.; Hagens, A.; van Braeckel, D.; Michielsen, K.

    2015-01-01

    In February 2014, an international congress on Promoting Adolescent Sexual and Reproductive Health (ASRH) took place in Cuenca, Ecuador. Its objective was to share evidence on effective ASRH intervention projects and programs in Latin America, and to link this evidence to ASRH policy and program

  13. Improving International Marketing Programs to Reflect Global Complexity and Risk: Curriculum Drivers and Constraints

    Science.gov (United States)

    Vos, Lynn

    2013-01-01

    This article looks at the curriculum redesign of a master's-level program in international marketing from a UK perspective. In order to ensure that the program would be more fit-for-purpose for future managers working under conditions of complexity, uncertainty, and within regimes often very different from the home market, the team began the…

  14. [Reflections on the concept of communication: second international goal of patient safety].

    Science.gov (United States)

    Medrano-Mariscal, Joel

    2015-01-01

    Effective communication is an element of prime importance, especially as it relates to health professional staff. Reflect on the concept and its meaning in a specific sector, taking into account their cultural and socio-environmental, requires interdisciplinary assistance in this case tools of medical anthropology as the emic view retake and construction of indicators are proposed. Medical anthropology and other social sciences, shows that the emic communication approach transcends the individual; so it is important to emphasize that communication has to be understood as a social construction, which helps to achieve understanding between people. Only from understanding the other will be able to think of an effective communication between health professionals.

  15. After Fukushima? On the educational and learning theoretical reflection of nuclear disasters. International perspectives

    International Nuclear Information System (INIS)

    Wigger, Lothar; Buenger, Carsten

    2017-01-01

    The book on the educational and learning theoretical reflection of nuclear disasters as a consequence of Fukushima includes contributions on the following issues: pedagogical approach: children write on Fukushima, description of the reality as pedagogical challenge; lessons learned on the nuclear technology - perspectives and limits of pedagogical evaluation: moral education - Japanese teaching materials, educational challenges at the universities with respect to nuclear technology and technology impact assessment; education and technology - questions concerning the pedagogical responsibility: considerations on the responsibility of scientists, on the discrepancy between technology and education, disempowerment of the public by structural corruption - nuclear disaster and post-democratic tendencies in Japan.

  16. Multielement analysis of swiss mice brains with Alzheimer's disease induced by beta amyloid oligomers using a portable total reflection X-ray fluorescence system

    International Nuclear Information System (INIS)

    Almeida, Danielle S.; Brigido, Matheus M.; Anjos, Marcelino J.; Ferreira, Sergio S.; Souza, Amanda S.; Lopes, Ricardo T.

    2017-01-01

    Alzheimer's disease (AD) is a progressive dementia that, in early stages, manifests as a profound inability to form new memories. The pathological features of AD include β-amyloid (Aβ) plaques, intracellular neurofibrillary tangles, loss of neurons and synapses, and activation of glia cells. Recently, several groups have raised the 'metal hypothesis' of AD. Metal ions, such as Cu and Zn, have been demonstrated to modulate amyloid aggregation along different pathways. Extensive research has been conducted on the effects of metals on Aβ aggregation and all of them have shown that both Cu and Zn accelerate the aggregation by shortening, or eliminating, the lag phase associated with the amyloid fibrillation process. The metal ions mentioned previously may have an important impact on the protein misfolding and the progression of the neurodegenerative process. The TXRF technique is very important, because can be used to identify and quantify trace elements present in the sample at very low concentrations (μg.g -1 ). In this work, three groups of females were studied: control, AD10 and AD100. The groups AD10 and AD100 were given a single intracerebroventricular injection of 10 pmol and 100 pmol of oligomers of β-amyloid peptide respectively to be induced AD. The TXRF measurements were performed using a portable total reflection X-ray fluorescence system developed in the Laboratory of Nuclear Instrumentation (LIN/UFRJ) that uses an X-ray tube with a molybdenum anode operating at 40 kV and 500 mA used for the excitation and a detector Si-PIN with energy resolution of 145 eV at 200 eV. It was possible to determine the concentrations of the following elements: P, S, K, Fe, Cu, Zn and Rubidium. Results showed differences in the elemental concentration in some brain regions between the AD groups and the control group. (author)

  17. Two different preparation techniques for trace element determination of single Daphnia specimen using total reflection x-ray fluorescence analysis (TXRF)

    International Nuclear Information System (INIS)

    Woelfl, S.; Mages, M.

    2000-01-01

    Bio accumulation gives first information about the bio-availability of elements in waters and becomes more and more important for the characterization of the water quality. The use of common analytical techniques like ICP-MS and AAS requires large quantities of biologic sample material. Single preparation for example of Daphnia, a common species for bio-test experiments, are hardly possible with these procedures. Therefore alternatively quantitative TXRF element determination of individually prepared Daphnia was developed. Two preparation techniques for single freshwater crustacean specimen from a eutrophic branch of the river Elbe in the 'Rothehorn Park', Magdeburg (Daphnia: dry weight: 10 - 50 μg individuum -1 ) had been tested: (1) Wet preparation: the single Daphnia specimen had been washed with 0.45 μm filtered lake water and put onto quartz sample carriers. After air drying, the body length were determined in order to calculate the dry weight according to previously established body lengths-dry weight relationships. (2) Dry preparation: after collection specimen were washed with 0.45 μm filtered lake water and frozen in liquid nitrogen. The individual lyophilisated dried Daphnia were weighted using an ultrafine micro-balance and put onto quartz sample carriers. After preparation, addition of some μl Gallium standard solution and air drying the individual Daphnia were digested at the quartz sample carriers with 10 μl HNO 3 on a hot plate and dried once more. Finally the element concentrations were determined using a EXTRA IIA total-reflection x-ray fluorescence spectrometer. As a result of these investigations we can conclude that both, the 'dry' and 'wet' preparation method can be used for the element determination in small single crustaceans using TXRF spectrometry. It seems that the 'dry' method yields more precise results, but the wet method is easier to handle in field when samples cannot be fixed with liquid nitrogen. (author)

  18. Enamel Mineral Content Changes After Bleaching With High and Low Hydrogen Peroxide Concentrations: Colorimetric Spectrophotometry and Total Reflection X-ray Fluorescence Analyses.

    Science.gov (United States)

    Pinto, Avd; Bridi, E C; Amaral, Flb; França, Fmg; Turssi, C P; Pérez, C A; Martinez, E F; Flório, F M; Basting, R T

    The purpose of this study was to evaluate the calcium (Ca) and phosphorous (P) content in enamel bleached with high and low concentrations of hydrogen peroxide (HP) using Total Reflection X-Ray Fluorescence (TXRF) and colorimetric spectrophotometry (SPEC). Forty-eight sound human third molars were used. Their roots were embedded in polystyrene resin and immersed for seven days in an artificial saliva solution. Then they were distributed into six groups to receive the bleaching treatments. The agents of high HP concentration (for in-office use) evaluated were Whiteness HP Maxx/FGM (35% HP), Whiteness HP Blue/FGM (35% HP, 2% calcium gluconate), Pola Office+/SDI (37.5% HP, 5% potassium nitrate), and Opalescence Boost/Ultradent (38% HP, 1.1% ion fluoride, 3% potassium nitrate); these agents were applied to enamel in three sessions. The agents of low HP concentration (for home use) evaluated were Pola Day/SDI (9.5% HP) and White Class 10%/FGM (10% HP, potassium nitrate, calcium, fluoride), and these agents were applied for 14 days. Enamel microbiopsies were evaluated by TXRF and SPEC analysis before the bleaching treatment (baseline), during the treatment, and 14 days after the end of the treatment. For TXRF, the Kruskal-Wallis test showed that Ca and P were not influenced by agent (p>0.05). For SPEC, Pola Office+, Opalescence Boost, Pola Day, and White Class 10% caused a decrease of Ca over time; there was a significant decrease of P over time to Pola Office+ and White Class 10%. The Spearman test showed no correlation between the Ca (p=0.987; r 2 =-0.020) and P (p=0.728, r 2 =0.038) obtained by SPEC and TXRF. For TXRF and SPEC, changes in Ca and P during bleaching occurred independently of the HP concentration used.

  19. Multielement analysis of swiss mice brains with Alzheimer's disease induced by beta amyloid oligomers using a portable total reflection X-ray fluorescence system

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Danielle S.; Brigido, Matheus M.; Anjos, Marcelino J.; Ferreira, Sergio S.; Souza, Amanda S.; Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.br, E-mail: marcelin@uerj.br, E-mail: amandass@bioqmed.ufrj.br, E-mail: ferreira@bioqmed.ufrj.br, E-mail: amandass@bioqmed.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Instituto de Fisica Armando Dias Tavares (Brazil)

    2017-11-01

    Alzheimer's disease (AD) is a progressive dementia that, in early stages, manifests as a profound inability to form new memories. The pathological features of AD include β-amyloid (Aβ) plaques, intracellular neurofibrillary tangles, loss of neurons and synapses, and activation of glia cells. Recently, several groups have raised the 'metal hypothesis' of AD. Metal ions, such as Cu and Zn, have been demonstrated to modulate amyloid aggregation along different pathways. Extensive research has been conducted on the effects of metals on Aβ aggregation and all of them have shown that both Cu and Zn accelerate the aggregation by shortening, or eliminating, the lag phase associated with the amyloid fibrillation process. The metal ions mentioned previously may have an important impact on the protein misfolding and the progression of the neurodegenerative process. The TXRF technique is very important, because can be used to identify and quantify trace elements present in the sample at very low concentrations (μg.g{sup -1}). In this work, three groups of females were studied: control, AD10 and AD100. The groups AD10 and AD100 were given a single intracerebroventricular injection of 10 pmol and 100 pmol of oligomers of β-amyloid peptide respectively to be induced AD. The TXRF measurements were performed using a portable total reflection X-ray fluorescence system developed in the Laboratory of Nuclear Instrumentation (LIN/UFRJ) that uses an X-ray tube with a molybdenum anode operating at 40 kV and 500 mA used for the excitation and a detector Si-PIN with energy resolution of 145 eV at 200 eV. It was possible to determine the concentrations of the following elements: P, S, K, Fe, Cu, Zn and Rubidium. Results showed differences in the elemental concentration in some brain regions between the AD groups and the control group. (author)

  20. The elemental changes occurring in the rat liver after exposure to PEG-coated iron oxide nanoparticles: total reflection x-ray fluorescence (TXRF) spectroscopy study.

    Science.gov (United States)

    Matusiak, Katarzyna; Skoczen, Agnieszka; Setkowicz, Zuzanna; Kubala-Kukus, Aldona; Stabrawa, Ilona; Ciarach, Małgorzata; Janeczko, Krzysztof; Jung, Aleksandra; Chwiej, Joanna

    The main goal of this study was to evaluate in vivo effects of low dose of PEG-coated magnetic iron oxide nanoparticles (IONPs) on the rat liver. The IONPs was intravenously injected into rats at a dose equaled to 0.03 mg of Fe per 1 kg of an animal body weight. The elemental composition of liver tissue in rats subjected to IONPs action and controls were compared. Moreover, in order to determine the dynamics of nanoparticles (NPs) induced elemental changes, the tissues taken from animals 2 hours, 24 hours, and 7 days from IONPs injection were examined. The analysis of subtle elemental anomalies occurring as a result of IONPs action required application of highly sensitive analytical method. The total reflection X-ray fluorescence spectroscopy perfectly meets such requirements and therefore it was used in this study. The obtained results showed increasing trend of Fe level within liver occurring 2 hours from IONPs injection. One day after NPs administration, the liver Fe content presented the baseline level what suggests only the short-term accumulation of nanoparticles in the organ. The Ca, Cu, and Zn levels changed significantly as a result of NPs action. Moreover, the anomalies in their accumulation were still observed 7 days after IONPs injection. The level of Cu decreased while those of Ca and Zn increased in the liver of NPs-treated animals. The reduced liver Cu, followed by elevated serum level of this element, might be related in triggering the mechanisms responsible for Fe metabolism in the organism.

  1. Multivariate analysis of Scotch whisky by total reflection x-ray fluorescence and chemometric methods: A potential tool in the identification of counterfeits.

    Science.gov (United States)

    Shand, Charles A; Wendler, Renate; Dawson, Lorna; Yates, Kyari; Stephenson, Hayleigh

    2017-07-11

    Most methods used in the identification of counterfeit whisky have focused on the profiling of volatile organic congeners determined by gas chromatography. We tested the use of total reflection x-ray fluorescence (TXRF) for trace element analysis of whisky and application of the data as a potential tool in the identification of counterfeit samples. Twenty five whiskies that were produced in different regions of Scotland or were blends, 5 counterfeit whiskies, 1 unmatured grain whisky, and 1 matured grain whisky were analysed for 11 elements (P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br and Rb). The effect of cold plasma ashing with oxygen on whisky residues evaporated on the TXRF reflector on the instrument performance was investigated. Cold plasma ashing with oxygen reduced beam scatter and improved the limits of detection but was ultimately deemed unnecessary. The element concentration data for whisky obtained by TXRF (after log transformation) was compared with the values obtained by inductively coupled plasma spectroscopy and showed correlation values (R 2 ) ≥ 0.942 for K, Mn and Cu: ≥ 0.800 for Ca, Fe and Rb; and ≥0.535 for P, S and Zn. The range of concentration values for individual elements was variable and principal components analysis of the elemental concentrations partially differentiated the whiskies by region or type but showed clear separation of the counterfeit samples from the other samples. Using the principal component scores of the elemental concentration data, linear discriminant analysis also distinguished the counterfeits from the other samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Selective Micellar Extraction of Ultratrace Levels of Uranium in Aqueous Samples by Task Specific Ionic Liquid Followed by Its Detection Employing Total Reflection X-ray Fluorescence Spectrometry.

    Science.gov (United States)

    Saha, Abhijit; Sanyal, Kaushik; Rawat, Neetika; Deb, Sadhan Bijoy; Saxena, Manoj Kumar; Tomar, Bhupendra Singh

    2017-10-03

    A task specific ionic liquid (TSIL) bearing phosphoramidate group, viz., N-propyl(diphenylphosphoramidate)trimethylammonium bis(trifluoromethanesulfonyl)imide, was synthesized and characterized by 1 H NMR, 13 C NMR, 31 P NMR, and IR spectroscopies, elemental (C H N S) analysis, and electrospray ionization mass spectrometry (ESI-MS). Using this TSIL a cloud point extraction (CPE) or micelle mediated extraction procedure was developed for preconcentration of uranium (U) in environmental aqueous samples. Total reflection X-ray fluorescence spectrometry was utilized to determine the concentration of U in the preconcentrated samples. In order to understand the mechanism of the CPE procedure, complexation study of the TSIL with U was carried out by isothermal calorimetric titration, liquid-liquid extraction, 31 P NMR and IR spectroscopies, and ESI-MS. The developed analytical technique resulted in quantitative extraction efficiency of 99.0 ± 0.5% and a preconcentration factor of 99 for U. The linear dynamic range and method detection limit of the procedure were found to be 0.1-1000 ng mL -1 and 0.02 ng mL -1 , respectively. The CPE procedure was found to tolerate a higher concentration of commonly available interfering cations and anions, especially the lanthanides. The developed analytical method was validated by determining the concentration of U in a certified reference material, viz., NIST SRM 1640a natural water, which was found to be in good agreement at a 95% confidence limit with the certified value. The method was successfully applied to the U determination in three natural water samples with ≤4% relative standard deviation (1σ).

  3. Leaf secretion composition of the mangrove species Avicennia germinans (L.) in relation to salinity: a case study by using total-reflection X-ray fluorescence analysis.

    Science.gov (United States)

    Sobrado; Greaves

    2000-10-16

    The aim here was to use total-reflection X-ray fluorescence (TXRF) to determine the elemental composition (besides Na), and the relative contribution of each element in leaf secretion of the mangrove species Avicennia germinans, grown under contrasting salinities (0-865 mol m(-3) NaCl). Na was determined by conventional atomic absorption spectrometry (AAS). Total secretion was 2.00+/-0.28 mmol m(-2) per day in control plants (at 0 NaCl) and increased progressively up to 46.87+/-7.14 mmol m(-2) per day at 865 mol m(-3) NaCl. Na and Cl accounted for 85.91+/-1.81% of the total secretion in control plants and about 96.32+/-0.30% in salt-treated plants. The excretion of Na exceeded that of Cl when salinity increased and this led to a progressive increase in Na/Cl ratios from 0.46+/-0.02 in control plants up to 2.75+/-0.42 (at 865 mol m(-3) NaCl). Other elements were also secreted in sizeable amounts such as K, S, Ca, Br and Zn. However, the relative importance of these elements, in terms of total secretion, was considerable in control plants (15% of the total secretion) and declined significantly under salinity treatments (total secretion). In conclusion, TXRF has been shown to be a powerful tool allowing quantitative determination of Cl (1.2-13 mmol m(-2) per day), secreted in relatively large quantities, as well as other elements secreted in intermediate (S, Ca and K; 0.07-1.00 mmol m(-2) per day) and in trace quantities (Br and Zn; 0.6-4 µmol m(-2) per day).

  4. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions.

    Science.gov (United States)

    Ingerle, D; Meirer, F; Pepponi, G; Demenev, E; Giubertoni, D; Wobrauschek, P; Streli, C

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  5. Developing international open science collaborations: Funder reflections on the Open Science Prize.

    Science.gov (United States)

    Kittrie, Elizabeth; Atienza, Audie A; Kiley, Robert; Carr, David; MacFarlane, Aki; Pai, Vinay; Couch, Jennifer; Bajkowski, Jared; Bonner, Joseph F; Mietchen, Daniel; Bourne, Philip E

    2017-08-01

    The Open Science Prize was established with the following objectives: first, to encourage the crowdsourcing of open data to make breakthroughs that are of biomedical significance; second, to illustrate that funders can indeed work together when scientific interests are aligned; and finally, to encourage international collaboration between investigators with the intent of achieving important innovations that would not be possible otherwise. The process for running the competition and the successes and challenges that arose are presented.

  6. International competence and knowledge studies and attitudes of the Brazilian Management accountant: analyses and reflections

    Directory of Open Access Journals (Sweden)

    Ricardo Lopes Cardoso

    2010-01-01

    Full Text Available The main purpose of this study is to understand what the competences of the Management accountant are, compare to international studies and assess the existence of competences to be prioritized. This questioning has as motivation the placements of Hardern (1995, Morgan (1997, IMA (1996 e 1999 and IFAC (2003. The theoretical basis about competences is related to McClelland study (1973, 1998, Boyatzis (1982 and Spencer and Spencer (1993. This research is based on the study of 18 competences about knowledge, skills and attitudes obtained in accountant literature and that have been submitted to 200 Management accountants. Data collection instrument presented a 0.884 Cronbach Alpha. From a factorial analysis and after Kruskal-Wallis test 12 competences were obtained as the most relevant segregated in 3 factors, in comparison to international studies of nine common competences 4 were not considered relevant in statistical tests and only one must be prioritized. Results demonstrate differences between competences required from Brazilian Management accountants and from other countries, being that their reasons is an open-ended question up to the moment.

  7. Indigenous Storytelling and Participatory Action Research: Allies Toward Decolonization? Reflections From the Peoples' International Health Tribunal.

    Science.gov (United States)

    Caxaj, C Susana

    2015-01-01

    Storytelling, in its various forms, has often been described as a practice with great emancipatory potential. In turn, Indigenous knowledge shows great promise in guiding a participatory action research (PAR) methodology. Yet these two approaches are rarely discussed in relation to one another, nor, has much been written in terms of how these two approaches may work synergistically toward a decolonizing research approach. In this article, I report on a community-driven knowledge translation activity, the Peoples' International Health Tribunal, as an exemplar of how narrative and PAR approaches, guided by local Indigenous knowledge, have great potential to build methodologically and ethically robust research processes. Implications for building globally relevant research alliances and scholarship are further discussed, particularly in relation to working with Indigenous communities.

  8. Is law failing to address air pollution? Reflections on international and EU developments.

    Science.gov (United States)

    Yamineva, Yulia; Romppanen, Seita

    2017-11-01

    Air pollution is a major global environmental problem, with various adverse effects on health and the environment. This introductory article provides an overview of related global and regional legal instruments. The article evaluates the legal landscape in terms of its coverage, geographic scope and effectiveness, and concludes that the legal measures currently in place fall far short of providing an adequate response to the problem of air pollution. Thus, there is a clear need to strengthen global and regional cooperation to improve air quality. Such cooperation is likely to take non-binding and flexible forms and involve both wider participation among States and broader engagement of various stakeholders. The informal character of cooperation also makes it possible to experiment with new governance approaches that are difficult to implement within the context of traditional international law.

  9. Green approach for ultratrace determination of divalent metal ions and arsenic species using total-reflection X-ray fluorescence spectrometry and mercapto-modified graphene oxide nanosheets as a novel adsorbent.

    Science.gov (United States)

    Sitko, Rafal; Janik, Paulina; Zawisza, Beata; Talik, Ewa; Margui, Eva; Queralt, Ignasi

    2015-03-17

    A new method based on dispersive microsolid phase extraction (DMSPE) and total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for multielemental ultratrace determination of heavy metal ions and arsenic species. In the developed methodology, the crucial issue is a novel adsorbent synthesized by grafting 3-mercaptopropyl trimethoxysilane on a graphene oxide (GO) surface. Mercapto-modified graphene oxide (GO-SH) can be applied in quantitative adsorption of cobalt, nickel, copper, cadmium, and lead ions. Moreover, GO-SH demonstrates selectivity toward arsenite in the presence of arsenate. Due to such features of GO-SH nanosheets as wrinkled structure and excellent dispersibility in water, GO-SH seems to be ideal for fast and simple preconcentration and determination of heavy metal ions using methodology based on DMSPE and TXRF measurement. The suspension of GO-SH was injected into an analyzed water sample; after filtration, the GO-SH nanosheets with adsorbed metal ions were redispersed in a small volume of internal standard solution and deposited onto a quartz reflector. The high enrichment factor of 150 allows obtaining detection limits of 0.11, 0.078, 0.079, 0.064, 0.054, and 0.083 ng mL(-1) for Co(II), Ni(II), Cu(II), As(III), Cd(II), and Pb(II), respectively. Such low detection limits can be obtained using a benchtop TXRF system without cooling media and gas consumption. The method is suitable for the analysis of water, including high salinity samples difficult to analyze using other spectroscopy techniques. Moreover, GO-SH can be applied to the arsenic speciation due to its selectivity toward arsenite.

  10. Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.

    Science.gov (United States)

    Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

    2008-12-10

    A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown.

  11. The International Association of Hydrogeologists (IAH): reflecting on 60 years of contributions to groundwater science and water management

    Science.gov (United States)

    Struckmeier, Willi; Howard, Ken; Chilton, John

    2016-08-01

    The 60th anniversary of the founding of the International Association of Hydrogeologists (IAH) is an important milestone that allows pause for reflection on how the association has evolved over the years and the contributions it has made to groundwater science and water management. IAH was founded in 1956 at the 20th International Geological Congress and developed rapidly during the 1980s and 1990s in response to a growing global interest in groundwater mapping and in sound approaches to resource protection and sustainable aquifer management. Incorporated in 2000, IAH has now secured its position as the world's leading international association specialising in groundwater with over 4,100 members in 131 countries. Much credit for this success must go to members, past and present, whose individual efforts and collaboration with sister institutions are documented here. These members have shaped the association's goals and contributed selflessly to its scientific programmes, publications and educational and charitable activities. Looking ahead to the next 60 years, it is essential that IAH does not rest on past achievements but listens and adjusts to the needs of members while continuing to pursue its mission of furthering the understanding, wise use and protection of groundwater resources throughout the world.

  12. 'How would you call this in English?' : Being reflective about translations in international, cross-cultural qualitative research.

    Science.gov (United States)

    Helmich, Esther; Cristancho, Sayra; Diachun, Laura; Lingard, Lorelei

    2017-04-01

    Medical education researchers increasingly collaborate in international teams, collecting data in different languages and from different parts of the world, and then disseminating them in English-language journals. Although this requires an ever-present need to translate, it often occurs uncritically. With this paper we aim to enhance researchers' awareness and reflexivity regarding translations in qualitative research. In an international study, we carried out interviews in both Dutch and English. To enable joint data analysis, we translated Dutch data into English, making choices regarding when and how to translate. In an iterative process, we contextualized our experiences, building on the social sciences and general health literature about cross-language/cross-cultural research. We identified three specific translation challenges: attending to grammar or syntax differences, grappling with metaphor, and capturing semantic or sociolinguistic nuances. Literature findings informed our decisions regarding the validity of translations, translating in different stages of the research process, coding in different languages, and providing 'ugly' translations in published research reports. The lessons learnt were threefold. First, most researchers, including ourselves, do not consciously attend to translations taking place in international qualitative research. Second, translation challenges arise not only from differences in language, but also from cultural or societal differences. Third, by being reflective about translations, we found meaningful differences, even between settings with many cultural and societal similarities. This conscious process of negotiating translations was enriching. We recommend researchers to be more conscious and transparent about their translation strategies, to enhance the trustworthiness and quality of their work.

  13. Study of air pollution in terms of heavy metals and particulate matter at Ambodin'isotry using the technique of total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    AHMED, H.

    2011-01-01

    The present work is devoted to study the air pollution in terms of particulate matters and heavy metals in Ambodin'isotry in Antananarivo city by the method of total reflection X-ray fluorescence. This work has been done within the Institut National des Sciences et Techniques Nucleaires (Madagascar-INSTN). GENT air sampler has been used for the collections of the aerosol samples. This air sampler is placed at about 7 meters above the ground in order to avoid the contaminations. The samplings were carried out from 14 April to 29 August 2008. The duration of sampling is 24 hours. The results show that the analyzed aerosol samples contain the elements like the titanium , the chromium, the manganese, the iron, the nickel, the copper, the zinc, the bromine, the strontium and the lead. The average concentrations in element lead are lower than the standards ones adopted by the World Health Organization (WHO) (500 ng.m -3 ) and the United States Environmental Protection Agency (US EPA) (1500 ng.m -3 ). The total average concentrations in element lead are lower than the standards ones adopted by the World Health Organization (WHO) (500 ng.m -3 ). The total of average concentrations in lead doesn't present a danger for the population of Ambodin'isotry. The average concentrations of PM10 in the aerosols do not respect the guideline values of 50μg.m -3 adopted by the WHO and the European Union according to the directive 2005 and those of PM 2.5 exceed extensively the guideline values of the WHO (25μg.m -3 ) and of the US EPA (35μg.m -3 ). Consequently, the site of Ambodin'Isotry is polluted in term of airborne particulate matters. The calculation of enrichment factors by Mason's model shows the titanium, the iron, the nickel and the strontium are natural origin while the chromium, the nickel, the copper, the zinc, the bromine and the lead are from anthropogenic sources. [fr

  14. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens.

    Science.gov (United States)

    Zhu, Chenggang; Ge, Bilin; Chen, Ru; Zhu, Xiangdong; Mi, Lan; Ma, Jiong; Wang, Xu; Zheng, Fengyun; Fei, Yiyan

    2018-02-09

    Total internal reflection (TIR) is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane) is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD) in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm² with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  15. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens

    Directory of Open Access Journals (Sweden)

    Chenggang Zhu

    2018-02-01

    Full Text Available Total internal reflection (TIR is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm2 with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  16. Enhanced detection sensitivity of carcinoembryonic antigen on a plasmonic nanoimmunosensor by transmission grating-based total internal reflection scattering microscopy.

    Science.gov (United States)

    Ahn, Sujin; Yu, Hyunung; Kang, Seong Ho

    2017-10-15

    Carcinoembryonic antigen (CEA) is a glycoprotein associated with colorectal carcinomas and is commonly used as a clinical tumor marker. Enhanced detection sensitivity for the assay of CEA molecules was achieved on a plasmonic nanoimmunosensor by wavelength-dependent transmission grating (TG)-based total internal reflection scattering microscopy (TIRSM). The plasmonic nanoparticles were placed in an evanescent field layer on a glass nanoimmunosensor that produced evanescent wave scattering by the total internal reflection of light from two lasers. The light scattered by target protein (CEA)-bound 20-nm silver nanoparticles (plasmonic nanoprobes) was collected and spectrally isolated in first-order spectral images (n=+1) by a TG (70 grooves/mm). The combination of evanescent wave scattering and TG ​significantly enhanced the detection sensitivity and selectivity due to the minimized spectroscopic interference and background noise. The TG-TIRSM method detected the CEA molecules at concentrations down to 19.75zM with a wide linear dynamic range of 19.75zM-39.50nM (correlation coefficient, R=0.9903), which was 45 to 1.25×10 9 times lower than the detection limits and 2×10 5 to 2×10 11 times wider than the dynamic ranges of previous assay methods. In particular, by simply changing the antibody of the target molecule, this technique can be used to detect various disease-related protein biomarkers directly in human biological samples at the single-molecule level. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Organic films deposited on Si p-n junctions: Accurate measurements of fluorescence internal efficiency, and application to luminescent antireflection coatings

    Science.gov (United States)

    Garbuzov, D. Z.; Forrest, S. R.; Tsekoun, A. G.; Burrows, P. E.; Bulović, V.; Thompson, M. E.

    1996-10-01

    Ultraviolet (UV) optical pumping followed by fluorescence wavelength downconversion of thin film organic light emitting materials deposited directly on the surface of Si p-n junction diodes is found to be an accurate and rapid means to determine the film internal fluorescence efficiency. By measuring the photoresponse of the Si detectors in the UV, we find that the organic light emitting films of aluminum tris-(8-hydroxyquinoline) (Alq3), N,N'-diphenyl-N,N'-bis-(3-methylphenyl)- 1,1'-biphenyl-4,4'-diamine, and bis-(8-hydroxyquinaldine)-chlorogallium (Gaq2'Cl), have internal fluorescence efficiencies of 0.30±0.05, 0.35±0.03, and 0.36±0.03, respectively. It has also been found that the organic films can be grown to a thickness which optimizes UV light conversion and can, at the same time, serve as antireflection coatings in the visible spectral region, thereby resulting in enhanced Si photodiode sensitivity extending from the UV to the infrared.

  18. Interfacing click chemistry with automated oligonucleotide synthesis for the preparation of fluorescent DNA probes containing internal xanthene and cyanine dyes

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Wengel, Jesper

    2013-01-01

    for the first time performed solid-phase copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click labeling during the automated phosphoramidite oligonucleotide synthesis followed by postsynthetic click reactions in solution. We demonstrate that our novel strategy is rapid and efficient for the preparation...... Stokes shifts (40-110 nm), quenched fluorescence of single-stranded probes accompanied by up to 7.7-fold light-up effect of emission upon target DNA/RNA binding, remarkable sensitivity to single-nucleotide mismatches, generally high fluorescence brightness values (FB up to 26), and hence low limit...

  19. Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

    Science.gov (United States)

    Kevin T. Smith; Jean Christophe Balouet; Walter C. Shortle; Michel Chalot; François Beaujard; Hakan Grudd; Don A. Vroblesky; Joel G. Burken

    2014-01-01

    Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to...

  20. Fluorescence Spectra of Highlighter Inks

    Science.gov (United States)

    Birriel, Jennifer J.; King, Damon

    2018-01-01

    Fluorescence spectra excited by laser pointers have been the subject of several papers in "TPT". These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by…

  1. Trace element analysis of water using radioisotope induced X-ray fluorescence (Cd-109) and a preconcentration-internal standard method

    International Nuclear Information System (INIS)

    Alvarez, M.; Cano, W.

    1986-10-01

    Radioisotope induced X-ray fluorescence using Cd-109 was used for the determination of iron, nickel, copper, zinc, lead and mercury in water. These metals were concentrated by precipitation with the chelating agent APDC. The precipitated formed was filtered using a membrane filter. Cobalt was added as an internal standard. Minimum detection limit, sensitivities and calibration curves linearities have been obtained to find the limits of the method. The usefulness of the method is illustrated analysing synthetic standard solutions. As an application analytical results are given for water of a highly polluted river area. (Author)

  2. Planar solar concentrator featuring alignment-free total-internal-reflection collectors and an innovative compound tracker.

    Science.gov (United States)

    Teng, Tun-Chien; Lai, Wei-Che

    2014-12-15

    This study proposed a planar solar concentrator featuring alignment-free total-internal-reflection (TIR) collectors and an innovative compound tracker. The compound tracker, combining a mechanical single-axis tracker and scrollable prism sheets, can achieve a performance on a par with dual-axis tracking while reducing the cost of the tracking system and increasing its robustness. The alignment-free TIR collectors are assembled on the waveguide without requiring alignment, so the planar concentrator is relatively easily manufactured and markedly increases the feasibility for use in large concentrators. Further, the identical TIR collector is applicable to various-sized waveguide slab without requiring modification, which facilitates flexibility regarding the size of the waveguide slab. In the simulation model, the thickness of the slab was 2 mm, and its maximal length reached 6 m. With an average angular tolerance of ±0.6°, and after considering both the Fresnel loss and the angular spread of the sun, the simulation indicates that the waveguide concentrator of a 1000-mm length provides the optical efficiencies of 62-77% at the irradiance concentrations of 387-688, and the one of a 2000-mm length provides the optical efficiencies of 52-64.5% at the irradiance concentrations of 645-1148. Alternatively, if a 100-mm horizontally staggered waveguide slab is collocated with the alignment-free TIR collectors, the optical efficiency would be greatly improved up to 91.5% at an irradiance concentration of 1098 (C(geo) = 1200X).

  3. Real time study of amalgam formation and mercury adsorption on thin gold film by total internal reflection ellipsometry

    Science.gov (United States)

    Paulauskas, A.; Selskis, A.; Bukauskas, V.; Vaicikauskas, V.; Ramanavicius, A.; Balevicius, Z.

    2018-01-01

    Total internal reflection ellipsometry (TIRE) was utilized in its dynamic data acquisition mode to reveal the percentage of mercury present in an amalgam surface layer. In determining the optical constants of the amalgam film, the non-homogeneities of the formed surface layer were taken into account. The composition of the amalgam layer by percentage was determined using the EMA Bruggemann model for the analysis of the TIRE data. Regression results showed that amalgam layer consisted of mercury 16.00 ± 0.43% and gold 84.00 ± 0.43%. This real time TIRE analysis has shown that for these studies method can detect 0.6 ± 0.4% of mercury on a gold surface, proving that this is a suitable optical technique for obtaining real time readouts. The structural analysis of SEM and AFM have shown that the amalgam layer had a dendritic structure, which formation was determined by the weak adhesion of the gold atoms onto its surface.

  4. Removing the effect of blooming from potential energy measurement by employing total internal reflection microscopy integrated with video microscopy.

    Science.gov (United States)

    Cao, Feng; Gong, Xiangjun; He, Chuanxin; Ngai, To

    2017-10-01

    Total internal reflection microscopy (TIRM) measures the interactions between a colloidal particle and a flat surface in aqueous solution. Recently, TIRM has further integrated with video microscopy (VM) and enabled the simultaneous measurements of multi-particle colloid-surface interactions in the same ensemble. However, there still remain challenges about accurate image acquisition due to blooming. Blooming means the number of photons reaching the detector exceeds its maximum capacity, and the excess photons will either spill to adjacent pixels or not be counted, leading to an obstacle from precise determination of intensity. Our result shows that blooming gives rise to a deviation of the measured potential energy from the classical theory of Derjaguin, Landau, Verway, and Overbeek (DLVO). Therefore, a correction method was developed in this work to deduce the real intensity from the experimental measurement. The relationship between scattered light intensity and exposure time deviates from linearity when blooming occurs. A correction equation was developed to recover the real intensity, which was then confirmed by the accordance between the corresponding potential energy profiles and the DLVO theory. This correction method is suitable for VM systems of colloidal probes illuminated by scattered light, broadening the application of VM imaging to investigate colloidal interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. The Advantages of an Attenuated Total Internal Reflection Infrared Microspectroscopic Imaging Technique for the Analysis of Polymer Laminates.

    Science.gov (United States)

    Ling, Chen; Sommer, André J

    2015-06-01

    Until recently, the analysis of polymer laminates using infrared microspectroscopy involved the painstaking separation of individual layers by dissection or by obtaining micrometer thin cross-sections. The latter usually requires the expertise of an individual trained in microtomy and even then, the very structure of the laminate could affect the outcome of the spectral results. The recent development of attenuated total internal reflection (ATR) infrared microspectroscopy imaging has provided a new avenue for the analysis of these multilayer structures. This report compares ATR infrared microspectroscopy imaging with conventional transmission infrared microspectroscopy imaging. The results demonstrate that the ATR method offers improved spatial resolution, eliminates a variety of competing optical processes, and requires minimal sample preparation relative to transmission measurements. These advantages were illustrated using a polymer laminate consisting of 11 different layers whose thickness ranged in size from 4-20 μm. The spatial resolution achieved by using an ATR-FTIR (Fourier transform infrared spectroscopy) imaging technique was diffraction limited. Contrast in the ATR images was enhanced by principal component analysis.

  6. Characterization of the external and internal flow structure of an aerated-liquid injector using X-ray radiography and fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, Scott J. [Aerospace Systems Directorate, Air Force Research Laboratory, Arnold AFB, TN (United States); Lin, Kuo-Cheng [Taitech, Inc., Beavercreek, OH (United States); Carter, Campbell D. [Aerospace Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH (United States); Kastengren, Alan L. [Argonne National Laboratory, X-Ray Science Division, Advanced Photon Source, Argonne, IL (United States)

    2017-09-15

    In the present study, the internal flowfield of aerated-liquid fuel injectors is examined through X-ray radiography and X-ray fluorescence. An inside-out injector, consisting of a perforated aerating tube within an annular liquid stream, sprays into a quiescent environment at a fixed mass flow rate of water and nitrogen gas. The liquid is doped with bromine (in the form of NaBr) to create an X-ray fluorescence signal. This allows for reasonable absorption and fluorescence signals, and one or both diagnostics can be used to track the liquid distribution. The injector housing is fabricated from beryllium (Be), which allows the internal flowfield to be examined (as Be has relatively low X-ray attenuation coefficient). Two injector geometries are compared, illustrating the effects of aerating orifice size and location on the flow evolution. Time-averaged equivalent pathlength and line-of-sight averaged density ρ(y) reveal the formation of the two-phase mixture, showing that the liquid film thickness along the injector walls is a function of the aerating tube geometry, though only upstream of the nozzle. These differences in gas and liquid distribution (between injectors with different aerating tube designs) are suppressed as the mixture traverses the nozzle contraction. The averaged liquid velocity (computed from the density and liquid mass flow rate) reveals a similar trend. This suggests that at least for the current configurations, the plume width, liquid mass distribution, and averaged liquid velocity for the time-averaged external spray are insensitive to the aerating tube geometry. (orig.)

  7. Characterization of the external and internal flow structure of an aerated-liquid injector using X-ray radiography and fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, Scott J.; Lin, Kuo-Cheng; Carter, Campbell D.; Kastengren, Alan L.

    2017-08-02

    In the present study, the internal flowfield of aerated-liquid fuel injectors is examined through x-ray radiography and x-ray fluorescence. An inside-out injector, consisting of a perforated aerating tube within an annular liquid stream, sprays into a quiescent environment at a fixed mass flow rate of water and nitrogen gas. The liquid is doped with bromine (in the form of NaBr) to create an x-ray fluorescence signal. This allows for reasonable absorption and fluorescence signals, and one or both diagnostics can be used to track the liquid distribution. The injector housing is fabricated from beryllium (Be), which allows the internal flowfield to be examined (as Be has relatively low x-ray attenuation coefficient). Two injector geometries are compared, illustrating the effects of aerating orifice size and location on the flow evolution. Time-averaged equivalent pathlength (EPL) and line-of-sight averaged density ρ(y) reveal the formation of the two-phase mixture, showing that the liquid film thickness along the injector walls is a function of the aerating tube geometry, though only upstream of the nozzle. These differences in gas and liquid distribution (between injectors with different aerating tube designs) are suppressed as the mixture traverses the nozzle contraction. The averaged liquid velocity (computed from the density and liquid mass flow rate) reveal a similar trend. This suggests that at least for the current configurations, the plume width, liquid mass distribution, and averaged liquid velocity for the time-averaged external spray are insensitive to the aerating tube geometry.

  8. Blogging as a tool to promote reflection among dietetic and physical therapy students during a multidisciplinary international service-learning experience.

    Science.gov (United States)

    Wright, Lauri; Lundy, Mary

    2012-01-01

    Service-learning is a guided, structured learning experience that engages students in service to a community for the mutual benefit of the student and community. There is a growing trend in healthcare to include international service-learning experiences in the training curriculum to promote cultural competence. A critical element of service-learning is reflection. There have been many research studies examining how best to support and facilitate the reflective thinking process in students. The purpose of this study was to assess the development of reflective thinking among graduate allied health students during an interdisciplinary international service-learning experience using a web-based collaborative blog. Twelve graduate students-six dietetic interns and six physical therapy doctoral students-traveled to Belize for 6 days to provide primary healthcare screenings and intervention to a community. Group blogging was found to be an effective tool to promote reflection in allied health student and short duration service-learning experience developed reflective thinking.

  9. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon FluxMeasurements ofMontanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Urban, Otmar; Hanuš, Jan; Zitová, Martina; Navrátil, M.; Vráblová, M.; Olejníčková, Julie; Špunda, V.; Marek, Michal V.

    2012-01-01

    Roč. 2012, č. 2012 (2012), s. 1-13 ISSN 1537-744X R&D Projects: GA MŽP(CZ) SP/2D1/70/08; GA MŽP(CZ) SP/2D1/93/07; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : Chlorophyll fluorescence * carbon flux * forest ecosystems * Norway Spruce * temperate zone Subject RIV: EH - Ecology, Behaviour Impact factor: 1.730, year: 2012

  10. Invited Article: An active terahertz polarization converter employing vanadium dioxide and a metal wire grating in total internal reflection geometry

    Science.gov (United States)

    Liu, Xudong; Chen, Xuequan; Parrott, Edward P. J.; Han, Chunrui; Humbert, Georges; Crunteanu, Aurelian; Pickwell-MacPherson, Emma

    2018-05-01

    Active broadband terahertz (THz) polarization manipulation devices are challenging to realize, but also of great demand in broadband terahertz systems. Vanadium dioxide (VO2) shows a promising phase transition for active control of THz waves and provides broadband polarization characteristics when integrated within grating-type structures. We creatively combine a VO2-based grating structure with a total internal reflection (TIR) geometry providing a novel interaction mechanism between the electromagnetic waves and the device, to realize a powerful active broadband THz polarization-controlling device. The device is based on a Si-substrate coated with a VO2 layer and a metal grating structure on top, attached to a prism for generating the TIR condition on the Si-VO2-grating interface. The grating is connected to electrodes for electrically switching the VO2 between its insulating and conducting phases. By properly selecting the incident angle of the THz waves, the grating direction, and the incident polarization state, we first achieved a broadband intensity modulator under a fused silica prism with an average modulation depth of 99.75% in the 0.2-1.1 THz region. Additionally, we realized an active ultra-broadband quarter-wave converter under a Si prism that can be switched between a 45° linear rotator and a quarter wave converter in the 0.8-1.5 THz region. This is the first demonstration of an active quarter-wave converter with ultra-broad bandwidth performance. Our work shows a highly flexible and multifunctional polarization-controlling device for broadband THz applications.

  11. Fluorescent labeling of Acanthamoeba assessed in situ from corneal sectioned microscopy.

    Science.gov (United States)

    Marcos, Susana; Requejo-Isidro, Jose; Merayo-Lloves, Jesus; Acuña, A Ulises; Hornillos, Valentin; Carrillo, Eugenia; Pérez-Merino, Pablo; Del Olmo-Aguado, Susana; Del Aguila, Carmen; Amat-Guerri, Francisco; Rivas, Luis

    2012-10-01

    Acanthamoeba keratitis is a serious pathogenic corneal disease, with challenging diagnosis. Standard diagnostic methods include corneal biopsy (involving cell culture) and in vivo reflection corneal microscopy (in which the visualization of the pathogen is challenged by the presence of multiple reflectance corneal structures). We present a new imaging method based on fluorescence sectioned microscopy for visualization of Acanthamoeba. A fluorescent marker (MT-11-BDP), composed by a fluorescent group (BODIPY) inserted in miltefosine (a therapeutic agent against Acanthamoeba), was developed. A custom-developed fluorescent structured illumination sectioned corneal microscope (excitation wavelength: 488 nm; axial/lateral resolution: 2.6 μm/0.4-0.6 μm) was used to image intact enucleated rabbit eyes, injected with a solution of stained Acanthamoeba in the stroma. Fluorescent sectioned microscopic images of intact enucleated rabbit eyes revealed stained Acanthamoeba trophozoites within the stroma, easily identified by the contrasted fluorescent emission, size and shape. Control experiments show that the fluorescent maker is not internalized by corneal cells, making the developed marker specific to the pathogen. Fluorescent sectioned microscopy shows potential for specific diagnosis of Acanthamoeba keratitis. Corneal confocal microscopy, provided with a fluorescent channel, could be largely improved in specificity and sensitivity in combination with specific fluorescent marking.

  12. Experimental and numerical studies of the scattering of light from a two-dimensional randomly rough interface in the presence of total internal reflection: optical Yoneda peaks.

    Science.gov (United States)

    González-Alcalde, Alma K; Banon, Jean-Philippe; Hetland, Øyvind S; Maradudin, Alexei A; Méndez, Eugenio R; Nordam, Tor; Simonsen, Ingve

    2016-11-14

    The scattering of polarized light from a dielectric film sandwiched between two different semi-infinite dielectric media is studied experimentally and theoretically. The illuminated interface is planar, while the back interface is a two-dimensional randomly rough interface. We consider here only the case in which the medium of incidence is optically more dense than the substrate, in which case effects due to the presence of a critical angle for total internal reflection occur. A reduced Rayleigh equation for the scattering amplitudes is solved by a rigorous, purely numerical, nonperturbative approach. The solutions are used to calculate the reflectivity of the structure and the mean differential reflection coefficient. Optical analogues of Yoneda peaks are present in the results obtained. The computational results are compared with experimental data for the in-plane mean differential reflection coefficient, and good agreement between theory and experiment is found.

  13. Using an Intention/Reflection Practice to Focus Students towards Future Professions in a Short-Term International Travel Experience

    Science.gov (United States)

    Fierke, Kerry K.; Lepp, Gardner A.; Bastianelli, Karen; Vogelsang, Lisa; Tornabene, Ladona

    2016-01-01

    The article describes a student-centered approach to generating meaningful learning outcomes in a short-term study abroad program. A practice named Intention/Reflection (I/R) was used to help students to identify, articulate, and reflect upon learning objectives that were personally meaningful, within the broader framework of the intended outcomes…

  14. Trace elements in airborne particles in internal industrial environments: spectrometric analysis of x-ray fluorescence (XRF)

    International Nuclear Information System (INIS)

    Salazar Matarrita, Alfonso

    2001-01-01

    Fluorescence spectroscopy x-ray, is a technique of non-destructive analysis, that allows quantitative determination of the absolute concentration of chemical elements that make up a given matrix. The detected elements depend on atomic number and energy of the secondary target used for irradiation of samples. X-rays are detected and counted in a spectroscopy system based on a multichannel analyzer, that discriminates by energy and form a spectrum of independent photopeaks, whose energy identifies the element and its intensity is proportional to its concentration. The quantification requires the irradiation and counting of a set of pattern comparators, of the same elements identified in the samples. The x-ray emission shows only during the time that the selected sample is subjected to irradiation by x-ray tube. This irradiation does not change the structure nor the chemical composition of the matrix, so the sample remains unchanged, after irradiation. This condition non-destructive characterizes the fluorescence x-ray. The trace elements present in airborne particles, are determined and collected on a Nuclepore filter. The collection sites selected are: Taller de Mecanica de Precision de la Escuela de Fisica, Universidad de Costa Rica; Taller J. V. G. Precision, San Antonio de Coronado; Taller de Muflas, MUFLASA, Alto de Guadalupe; Industria Silvania S. A., Pavas. In addition, it is attached the service rendered to the enterprise Sellos Generales S. A. The working conditions and physical conditions of facilities were considered. An aerosol sampler with a temporal variation was used. Irradiation of samples and an evaluation of the concentrations have been made. (author) [es

  15. Immunities of International Organizations before Domestic Courts : Reflections on the Collective Labour Case against the European Patent Organization

    NARCIS (Netherlands)

    Ryngaert, C.M.J.

    2016-01-01

    The Netherlands is home to a substantial number of international organizations, which on the basis of international agreements are entitled to immunity from jurisdiction and enforcement before Dutch courts. This immunity grant has not stopped claimants from suing international organizations in The

  16. Total reflection X-ray fluorescence spectrometry as a tool for the quantification of gold and platinum metallodrugs: determination of recovery rates and precision in the ppb concentration range.

    Science.gov (United States)

    Meyer, Andreas; Grotefend, Sandra; Gross, Armin; Wätzig, Hermann; Ott, Ingo

    2012-11-01

    Total reflection X-ray spectrometry is an instrumental technique based on X-ray fluorescence, which offers detection limits low enough to quantify trace element concentrations with negligible interference from matrix components. The technique is well established in material sciences and now reaches out to extended applications in life sciences and pharmaceutical quality control. In our study we focused on possible applications for the quantification of gold and platinum containing active ingredients in trace concentrations (ppb range) in a matrix of biological origin (cell suspensions). General aspects of sample preparation as well as selected important method performance parameters (precision, recovery rates) were investigated. Overall, TXRF represents an useful option to quantify metals in ppb concentrations with acceptable precision and recovery. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Conceptual Reflections on Ethics for International Research Collaborations in Disaster Impacted Areas from the Experiences in Indonesia, New Zealand and Japan

    Directory of Open Access Journals (Sweden)

    Christopher Gomez

    2014-12-01

    Full Text Available The present contribution is by no means a first attempt at considering the ethics in human activities, interactions in disaster impacted areas, but it is more the case of looking at 'international research' that present a very particular difficulty for ethics: the notion of trans-boundary, multi-dimensional idea of one group not really belonging within another, but which will perform functions inside this second group and eventually alter, modify some of the original organs. This paper explain the reflections of the ethical consideration of international research collaboration in disaster impacted areas which are emerged from the experiences in Indonesia, New Zealand and Japan.

  18. Single- and dual-fiber fluorescence probes: application to oil-film measurements in an internal combustion engine.

    Science.gov (United States)

    Ghandhi, J B

    2000-10-20

    Single- and dual-fiber fluorescence probes have been utilized to study oil-film behavior in a firing Diesel engine. A detailed analysis of the response characteristics of these probes was performed, and universal response curves have been generated through identification of the appropriate nondimensional parameters. For single-fiber probes a single curve was obtained, and for dual-fiber probes families of curves were identified based on three geometric dimensionless parameters. The complementary response characteristics of the single- and dual-fiber probes allows determination of the oil distribution within the piston-liner gap. The dual-fiber probe is not sensitive at small distances. Thus its signal originates solely from the piston surface, whereas the single-fiber probe is most sensitive at small distances and hence to the wall oil film. The engine data from the dual-fiber probe confirmed the presence of an oil film on the piston and provided a means of quantifying the transport of this oil within the engine.

  19. Implementing the First Cross-border Professional Development Online Course through International E-mentoring: Reflections and Perspectives

    Directory of Open Access Journals (Sweden)

    Buddhini Gayathri Jayatilleke

    2017-03-01

    Full Text Available This research paper discusses the accomplishments, issues, and challenges experienced by Open University of Sri Lanka (OUSL academics when offering the first cross-border professional development online course to train online tutors and mentors. The course was delivered exclusively online and facilitated by OUSL academics and e-mentors from the USA. The course was comprised of 30 participants: 9 from Pakistan, 10 from Mauritius and 11 from Sri Lanka. This qualitative study is based on reflections of both faculty and participants. Data were collected using reflections and informal anecdotal records of the three OUSL academics and self-reflection instruments (pre, mid and final administered to participants, and reflective journal entries made by participants. Participants’ views were triangulated with the reflections of the OUSL academics to validate the results. While there were many accomplishments in the design and delivery of the course, the findings revealed that there were many challenges in implementing the course: pedagogical, organizational and technological aspects in particular. The paper provides recommendations to address such challenges when offering cross-border online courses in the future.

  20. Effects of temperature on fluorescence in human tissue

    Science.gov (United States)

    Masters, D. B.; Walsh, Alex; Welch, A. J.; Mahadevan-Jansen, Anita

    2010-02-01

    The fluorescence properties of human tissue are known to be temperature dependent. The most apparent effect of this dependence is the inverse relationship between fluorescence and temperature. In this study, we used fluorescence and diffuse-reflectance spectroscopy to investigate the effects of temperature on fluorescence, thermal coagulation, and tissue optical properties. Human tissue from the breast and abdomen were examined in vitro, and human skin was examined in vivo using a fluorescence and diffuse-reflectance system to observe the effects of temperature on fluorescence and optical properties. Fluorescence measurements were carried out using a pulsed nitrogen laser at 337 nm for excitation and a thermal camera for temperature measurements. Thermal variation of the specimens was provided by a phosphate buffered saline solution for the in vitro experiments and an ice pack and heat lamp for the in vivo experiments. In vitro temperatures varied from 0°C to 70°C and in vivo temperatures varied from 15°C to 40°C. Optical property measurements and Monte Carlo simulations were carried out on the in vitro samples for different levels of thermal exposure. Results of both the in vivo and in vitro experiments indicate that optical properties of human tissue change at high temperatures, primarily due to increased scattering. In addition, certain internal processes may have contributed to a decrease in fluorescence with increasing temperature. Some of these effects were found to be reversible before a certain temperature threshold, while some effects of coagulation on fluorescence and optical properties were not reversible.

  1. Dual fluorescence labeling of surface-exposed and internal proteins in erythrocytes infected with the malaria parasite Plasmodium falciparum

    DEFF Research Database (Denmark)

    Bengtsson, Dominique C; Sowa, Kordai M P; Arnot, David E

    2008-01-01

    There is a need for improved methods for in situ localization of surface proteins on Plasmodium falciparum-infected erythrocytes to help understand how these antigens are trafficked to, and positioned within, the host cell membrane. This protocol for confocal immunofluorescence microscopy combines...... is discussed here in the context of malaria parasite-infected cells, it can also be modified to visualize the membrane and intracellular distribution of surface and internal proteins in other eukaryotic cells....

  2. Rethinking the Employability of International Graduate Migrants: Reflections on the Experiences of Zimbabweans with Degrees from England

    Science.gov (United States)

    McGrath, Simon; Madziva, Roda; Thondhlana, Juliet

    2017-01-01

    The last decade has seen the rise of literature focused on the rapid expansion of international students in higher education globally and the growing policy discourse around improving graduate employability. However, both, inevitably, have limitations. Together, they tend to homogenise international learners and see them narrowly as simply…

  3. 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...

  4. Ethical principles in international nuclear trade and the role of international treaties and agreements in their implementation. Reflections on the future

    International Nuclear Information System (INIS)

    Cavalanti, C. de A.

    1992-01-01

    The growing importance of nuclear energy (on the threshold of the twenty-first century) and of its ethical uses is considered, including major political events in recent years, their social and economic consequences in the world scene. International Nuclear Law is seen as the most adequate instrument to promote the ethical uses of nuclear energy on a worldwide basis, so that mankind can benefit safely and properly and improving their living conditions in general. Problems associated with access to nuclear technology, plants, equipments and materials are addressed. Basic principles of international agreements ruling nuclear trade, ethical aspects are also covered. The different markets involved in international nuclear trade and their specific requirements are described. Certain international treaties on the peaceful uses of nuclear energy are discussed such as the Non-Proliferation Treaty and the Tlatelolco Treaty as are international conventions on matters related to the use of nuclear energy, such as the environment and protection of personnel. The author concludes by debating whether ethical uses of nuclear energy are a possible reality or merely utopia. Prospects on the future of international nuclear trade are considered. (author)

  5. College Athletes' Reflective Judgment: A Moderator between Sport and Sociocultural Pressures, Body Ideal Internalization, and Body Dissatisfaction

    Science.gov (United States)

    Greene, Catie A.

    2016-01-01

    The purpose of this research was to investigate the sociocultural model of eating disorder development among male and female college student-athletes as moderated by students' level of Reflective Judgment, a stage theory of adult epistemology marked by increasing cognitive complexity. A review of literature on the established relationships between…

  6. A tool for clinical reasoning and reflection using the international classification of functioning, disability and health (ICF) framework and patient management model.

    Science.gov (United States)

    Atkinson, Heather L; Nixon-Cave, Kim

    2011-03-01

    Professional development is a cornerstone of physical therapist practice. As the profession moves toward the ideals of Vision 2020, more emphasis is being placed on the process of clinical decision making. Although reflection and mentorship are widely regarded as important instruments to facilitate the progression of clinical reasoning skills, little guidance exists in the postprofessional arena to assist clinicians with these essential needs. As more organizations develop formal mentoring programs, a need arises for a tool that will engage mentors, protégés, and clinicians of all abilities in thoughtful reflection and discussion that will help develop clinical reasoning skills. The process of developing reflective clinical decision-making skills in physical therapist practitioners is described, and how this process was used at one institution is illustrated. A tool for clinical reasoning and reflection is proposed that incorporates the existing conceptual frameworks of the Guide to Physical Therapist Practice and the International Classification of Functioning, Disability and Health (ICF). This case report discusses how the tool was implemented by staff with varying levels of expertise, their outcomes in regard to the development of their clinical reasoning skills, and how the tool facilitated mentoring sessions around patient cases to improve care. This case report describes a practical application of a postprofessional educational process designed to develop reflective and patient-centered clinical reasoning skills. Although this process has shown some preliminary success, more research is warranted. By cultivating reflective thinking and critical inquiry, the physical therapy profession can help develop autonomous practitioners of physical therapy and promote the ideals of Vision 2020.

  7. Maximising Intercultural Learning in Short Term International Placements: Findings Associated with Orientation Programs, Guided Reflection and Immersion

    Science.gov (United States)

    Campbell, Coral J. L.; Walta, Caroline

    2015-01-01

    Short-term international practicum experience is now a feature of many university education programs in Australia in an attempt to engage students with the growing multi-cultural aspects of Australian life. The stated purposes of such practicum experiences generally highlight intercultural learning, which is associated with the development of…

  8. Standard Setting for Next Generation TOEFL Academic Speaking Test (TAST): Reflections on the ETS Panel of International Teaching Assistant Developers

    Science.gov (United States)

    Papajohn, Dean

    2006-01-01

    While many institutions have utilized TOEFL scores for international admissions for many years, a speaking section has never before been a required part of TOEFL until the development of the iBT/Next Generation TOEFL. So institutions will need to determine how to set standards for the speaking section of TOEFL, also known as TOEFL Academic…

  9. Capacity Building in Southern Africa: Experiences and Reflections--Towards Joint Knowledge Production and Social Change in International Development Cooperation

    Science.gov (United States)

    Zeelen, Jacques; van der Linden, Josje

    2009-01-01

    The intent of capacity building in international development cooperation is to enable people to control their own development. Important premises are ownership, choice and self-esteem. The authors analyse the dynamics of the enabling process in practice, based on their own experiences working for several years in universities in developing…

  10. Reflective practice and social responsibility in family medicine: Effect of performing an international rotation in a developing country.

    Science.gov (United States)

    Loignon, Christine; Gottin, Thomas; Valois, Carol; Couturier, François; Williams, Robert; Roy, Pierre-Michel

    2016-11-01

    To explore the perceived effect of an elective international health rotation on family medicine resident learning. Qualitative, collaborative study based on semistructured interviews. Quebec. A sample of 12 family medicine residents and 9 rotation supervisors (N = 21). Semistructured interviews of residents and rotation supervisors. Residents and supervisors alike reported that their technical skills and relationship skills had benefited. All increased their knowledge of tropical pathologies and learned to expand their clinical examinations. They benefited from having very rich interactions in other care settings, working with vulnerable populations. The rotations had their greatest effect on relationship skills (communication, empathy, etc) and the ability to work with vulnerable patients. All of the participants were exposed to local therapies and local interpretations of disease symptoms and pathogenesis. The findings of this study will have a considerable effect on pedagogy. The residents' experiences of their international health rotations and what they learned in terms of medical skills and pedagogic approaches in working with patients are described. Using a collaborative approach with the rotation supervisors, the data were triangulated and the benefits of an international rotation on academic training were more accurately defined. The findings can now be used to enrich academic programs in social and preventive medicine and more adequately prepare future family physicians for work in various social and cultural settings. Copyright© the College of Family Physicians of Canada.

  11. Use of total internal reflection Raman (TIR) and attenuated total reflection infrared (ATR-IR) spectroscopy to analyze component separation in thin offset ink films after setting on coated paper surfaces.

    Science.gov (United States)

    Kivioja, Antti; Hartus, Timo; Vuorinen, Tapani; Gane, Patrick; Jääskeläinen, Anna-Stiina

    2013-06-01

    The interactive behavior of ink constituents with porous substrates during and after the offset print process has an important effect on the quality of printed products. To help elucidate the distribution of ink components between the retained ink layer and the substrate, a variety of spectroscopic and microscopic analysis techniques have been developed. This paper describes for the first time the use of total internal reflection (TIR) Raman spectroscopy to analyze the penetration behavior of separated offset ink components (linseed oil, solid color pigment) in coated papers providing chemically intrinsic information rapidly, nondestructively, and with minimal sample preparation. In addition, the already widely applied technique of attenuated total reflection infrared spectroscopy (ATR-IR) was evaluated in parallel and compared. The results of the ATR-IR Raman clearly revealed an improvement in uppermost depth resolution compared with values previously published from other nondestructive techniques, and the method is shown to be capable of providing new knowledge of the setting of thin (0.25-2 μm) offset ink films, allowing the spreading and the penetration behavior on physically different paper coating surfaces to be studied.

  12. Analysis of trace and mineral elements in vanilla pods from the region of S.A.V.A using total reflection X-ray fluorescence, atomic absorption and ion chromatography techniques

    International Nuclear Information System (INIS)

    Be, K.

    2013-01-01

    In the case of studies of food security, - arsenic, cobalt, chromium, copper, iron, manganese, nickel, rubidium, selenium, strontium, titanium, zinc - cadmium, lead - are almost always analyzed. Guide values are used to express the level of quality in matter of consumption. Analytical laboratories of Madagascar-INSTN outline usually their research on quantifying those elements by using two different analytical methods, the Total Reflection X-Ray Fluorescence for the first twelve metals and the Atomic Absorption Spectrometry dedicated to lead and cadmium. Supplementary analysis is carried out for the quantification of essential mineral elements such as calcium, magnesium and potassium by using Ion Chromatograph. The aim of this study was to set up the analysis of the above mentioned elements in vanilla pods collected from Sambava, Antalaha and Andapa for a routine use. After all the parameters were established, the validation was particularly focused on the limits of detection and quantification and the accuracy of each element. The used methods fulfil the scope of application needed and are easy to use in routine. [fr

  13. Impact of Lipid Oxidization on Vertical Structures and Electrostatics of Phospholipid Monolayers Revealed by Combination of Specular X-ray Reflectivity and Grazing-Incidence X-ray Fluorescence.

    Science.gov (United States)

    Korytowski, Agatha; Abuillan, Wasim; Makky, Ali; Konovalov, Oleg; Tanaka, Motomu

    2015-07-30

    The influence of phospholipid oxidization of floating monolayers on the structure perpendicular to the global plane and on the density profiles of ions near the lipid monolayer has been investigated by a combination of grazing incidence X-ray fluorescence (GIXF) and specular X-ray reflectivity (XRR). Systematic variation of the composition of the floating monolayers unravels changes in the thickness, roughness and electron density of the lipid monolayers as a function of molar fraction of oxidized phospholipids. Simultaneous GIXF measurements enable one to qualitatively determine the element-specific density profiles of monovalent (K(+) or Cs(+)) and divalent ions (Ca(2+)) in the vicinity of the interface in the presence and absence of two types of oxidized phospholipids (PazePC and PoxnoPC) with high spatial accuracy (±5 Å). We found the condensation of Ca(2+) near carboxylated PazePC was more pronounced compared to PoxnoPC with an aldehyde group. In contrast, the condensation of monovalent ions could hardly be detected even for pure oxidized phospholipid monolayers. Moreover, pure phospholipid monolayers exhibited almost no ion specific condensation near the interface. The quantitative studies with well-defined floating monolayers revealed how the elevation of lipid oxidization level alters the structures and functions of cell membranes.

  14. Wavelength-dispersive total-reflection X-ray fluorescence with an efficient Johansson spectrometer and an undulator X-ray source: detection of 10-16 g-level trace metals.

    Science.gov (United States)

    Sakurai, Kenji; Eba, Hiromi; Inoue, Katsuaki; Yagi, Naoto

    2002-09-01

    The present paper reports significant enhancement of the detection power for total-reflection X-ray fluorescence (TXRF). The employment of an efficient wavelength-dispersive spectrometer rather than a conventional Si(Li) detector, as well as the use of a quasi-monochromatic undulator X-ray source, completely changed the quality of X-ray florescence spectra. The energy resolution is 20 times better, which effectively contributes to reducing the low-energy tail of the scattering background and to separating neighboring X-ray florescence peaks. Another advantage is its capability with respect to high-counting-rate measurements, which ensure the detection of weak signals from trace materials. The absolute and relative detection limit for nickel are 3.1 x 10(-16) g and 3.1 ppt (pg/g) for a 0.1-microL droplet of pure water, respectively, which is nearly 50 times better than the current best data achieved by conventional energy-dispersive TXRF using a Si(Li) detector system.

  15. Unraveling transition metal dissolution of Li1.04Ni1/3Co1/3Mn1/3O2 (NCM 111) in lithium ion full cells by using the total reflection X-ray fluorescence technique

    Science.gov (United States)

    Evertz, Marco; Horsthemke, Fabian; Kasnatscheew, Johannes; Börner, Markus; Winter, Martin; Nowak, Sascha

    2016-10-01

    In this work we investigated the transition metal dissolution of the layered cathode material Li1.04Ni1/3Co1/3Mn1/3O2 in dependence on the cycle number and cut-off cell voltage during charge by using the total reflection X-ray fluorescence technique for the elemental analysis of the specific lithium ion battery degradation products. We could show that with ongoing cycling transition metal dissolution from the cathode increased over time. However, it was less pronounced at 4.3 V compared to elevated charge cut-off voltages of 4.6 V. After a maximum of 100 cycles, we detected an overall transition metal loss of 0.2 wt‰ in relation to the whole cathode active material for cells cycled to 4.3 V. At an increased charge cut-off voltage of 4.6 V, 4.5 wt‰ transition metal loss in relation to the whole cathode active material could be detected. The corresponding transition metal dissolution induced capacity loss at the cathode could thus be attributed to 1.2 mAh g-1. Compared to the overall capacity loss of 80 mAh g-1 of the complete cell after 100 galvanostatic charge/discharge cycles the value is quite low. Hence, the overall full cell capacity fade cannot be assigned exclusively to the transition metal dissolution induced cathode fading.

  16. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    Reflection has moved from the margins to the mainstream in supervision. Notions of reflection have become well established since the late 1980s. These notions have provided useful framing devices to help conceptualize some important processes in guidance and counseling. However, some applications...... of these notions have distorted their original connotations and taken an excessively instrumentalistic and individualistic approach to their use. This paper will argue that we are, in the 2000s, seeing a questioning of an overly instrumentalistic and individualistic view of learning and development previously...... associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...

  17. A hybrid total internal reflection fluorescence and optical tweezers microscope to study cell adhesion and membrane protein dynamics of single living cells

    NARCIS (Netherlands)

    Snijder-van As, M.I.; Rieger, B.; Joosten, B.; Subramaniam, Vinod; Figdor, Carl; Kanger, Johannes S.

    2009-01-01

    The dynamics of cell surface membrane proteins plays an important role in cell–cell interactions. The onset of the interaction is typically not precisely controlled by current techniques, making especially difficult the visualization of early-stage dynamics. We have developed a novel method where

  18. Enhanced sensitivity to dielectric function and thickness of absorbing thin films by combining total internal reflection ellipsometry with standard ellipsometry and reflectometry

    International Nuclear Information System (INIS)

    Lizana, A; Foldyna, M; Garcia-Caurel, E; Stchakovsky, M; Georges, B; Nicolas, D

    2013-01-01

    High sensitivity of spectroscopic ellipsometry and reflectometry for the characterization of thin films can strongly decrease when layers, typically metals, absorb a significant fraction of the light. In this paper, we propose a solution to overcome this drawback using total internal reflection ellipsometry (TIRE) and exciting a surface longitudinal wave: a plasmon-polariton. As in the attenuated total reflectance technique, TIRE exploits a minimum in the intensity of reflected transversal magnetic (TM) polarized light and enhances the sensitivity of standard methods to thicknesses of absorbing films. Samples under study were stacks of three films, ZnO : Al/Ag/ZnO : Al, deposited on glass substrates. The thickness of the silver layer varied from sample to sample. We performed measurements with a UV–visible phase-modulated ellipsometer, an IR Mueller ellipsometer and a UV–NIR reflectometer. We used the variance–covariance formalism to evaluate the sensitivity of the ellipsometric data to different parameters of the optical model. Results have shown that using TIRE doubled the sensitivity to the silver layer thickness when compared with the standard ellipsometry. Moreover, the thickness of the ZnO : Al layer below the silver layer can be reliably quantified, unlike for the fit of the standard ellipsometry data, which is limited by the absorption of the silver layer. (paper)

  19. Social assistance and disability in Brazil: the reflection of the international debate of the rights of people with disability

    Directory of Open Access Journals (Sweden)

    Wederson Rufino dos Santos

    2010-07-01

    Full Text Available This paper reviews the debate on the social model of disability has influenced conceptions of the International Classification of Functioning, Disability and Health adopted by the World Health Organization in 2001 and adopted in Brazil in 2007, through the law of the Continuous Cash Benefit. The BPC is a major social policy of income transfer to poor disabled people, affecting over one million and half disabled people in the country. Since 2009, the evaluation of persons with disabilities for the BPC will make by medical and social skills targeted by ICF. Will be demonstrated that, although the adoption of the ICF maybe to represent regard to how to understand disability as social inequality, the adoption of the ICF by the law of the BPC will face challenges in ensuring the right to dignity of disabled people.

  20. Growth curves and the international standard: How children's growth reflects challenging conditions in rural Timor-Leste.

    Science.gov (United States)

    Spencer, Phoebe R; Sanders, Katherine A; Judge, Debra S

    2018-02-01

    Population-specific growth references are important in understanding local growth variation, especially in developing countries where child growth is poor and the need for effective health interventions is high. In this article, we use mixed longitudinal data to calculate the first growth curves for rural East Timorese children to identify where, during development, deviation from the international standards occurs. Over an eight-year period, 1,245 children from two ecologically distinct rural areas of Timor-Leste were measured a total of 4,904 times. We compared growth to the World Health Organization (WHO) standards using z-scores, and modeled height and weight velocity using the SuperImposition by Translation And Rotation (SITAR) method. Using the Generalized Additive Model for Location, Scale and Shape (GAMLSS) method, we created the first growth curves for rural Timorese children for height, weight and body mass index (BMI). Relative to the WHO standards, children show early-life growth faltering, and stunting throughout childhood and adolescence. The median height and weight for this population tracks below the WHO fifth centile. Males have poorer growth than females in both z-BMI (p = .001) and z-height-for-age (p = .018) and, unlike females, continue to grow into adulthood. This is the most comprehensive investigation to date of rural Timorese children's growth, and the growth curves created may potentially be used to identify future secular trends in growth as the country develops. We show significant deviation from the international standard that becomes most pronounced at adolescence, similar to the growth of other Asian populations. Males and females show different growth responses to challenging conditions in this population. © 2017 Wiley Periodicals, Inc.

  1. Internal Marketing and Reflective Subjects Formation Marketing Interno e a Formação de Sujeitos Reflexivos

    Directory of Open Access Journals (Sweden)

    Sérgio Carvalho Benício de Mello

    2011-03-01

    Full Text Available Internal marketing perspective has gaining primordial space. It happens through an interdisciplinary process with human management discipline and is based on the assumption that a significant part of the organizational success depends on the attitudes, commitment and performance of people in an organization, above all the ones that interact with the customers. Assuming the premise that such procedure depends on the relationship between the contact employees and the customers of an organization, we revise in this essay fundamental notions of interpresonel relationships to discuss the role of the internal marketing in the formation of employees that becomes reflexive subjects. We understand such premise as a fundamental characteristic for those to carry out his/her role in a conscious way. Our conclusion is a theoretical proposal of how this can be developed.A perspectiva do marketing interno tem ganho espaço primordial. Isto ocorre por meio de um processo interdisciplinar com a gestão de pessoas, por se compreender que parte do êxito organizacional dependa das atitudes, do comprometimento e do desempenho de todos os envolvidos numa organização, sobretudo os que interagem com os clientes. Assumindo a premissa de que tal procedimento dependa do relacionamento entre o funcionário de contato e os clientes de uma organização, neste ensaio teórico revisamos noções fundamentais do conhecimento acerca das relações interpessoais para discutir o papel do marketing interno na formação de funcionários que se tornem sujeitos reflexivos. Tal premissa é por nos compreendida como característica fundamental para que estes desempenhem seu papel de forma consciente. Nossa chegada é uma proposta teórica de como isto possa ser desenvolvido.

  2. Effects of a strong magnetic field on internal gravity waves: trapping, phase mixing, reflection and dynamical chaos

    Science.gov (United States)

    Loi, Shyeh Tjing; Papaloizou, John C. B.

    2018-04-01

    The spectrum of oscillation modes of a star provides information not only about its material properties (e.g. mean density), but also its symmetries. Spherical symmetry can be broken by rotation and/or magnetic fields. It has been postulated that strong magnetic fields in the cores of some red giants are responsible for their anomalously weak dipole mode amplitudes (the "dipole dichotomy" problem), but a detailed understanding of how gravity waves interact with strong fields is thus far lacking. In this work, we attack the problem through a variety of analytical and numerical techniques, applied to a localised region centred on a null line of a confined axisymmetric magnetic field which is approximated as being cylindrically symmetric. We uncover a rich variety of phenomena that manifest when the field strength exceeds a critical value, beyond which the symmetry is drastically broken by the Lorentz force. When this threshold is reached, the spatial structure of the g-modes becomes heavily altered. The dynamics of wave packet propagation transitions from regular to chaotic, which is expected to fundamentally change the organisation of the mode spectrum. In addition, depending on their frequency and the orientation of field lines with respect to the stratification, waves impinging on different parts of the magnetised region are found to undergo either reflection or trapping. Trapping regions provide an avenue for energy loss through Alfvén wave phase mixing. Our results may find application in various astrophysical contexts, including the dipole dichotomy problem, the solar interior, and compact star oscillations.

  3. Reflections on nuclear challenges today. 6 December 2005, London, UK, International Institute for Strategic Studies, Allistair Buchan Lecture

    International Nuclear Information System (INIS)

    ElBaradei, M.

    2005-01-01

    Emerging nuclear challenges are proliferation of nuclear weapons and sensitive nuclear technologies, emergence of nuclear clandestine procurement networks in nuclear materials and equipment and the sluggishment in nuclear disarmament. Practical steps to address them are 1) better control of access to nuclear fuel cycle technology; 2) supporting effective nuclear verification; 3) strengthening the credibility of enforcement mechanisms; 4) protecting nuclear material and 5) developing an alternative approach to collective security. For better control of access to nuclear fuel cycle technology a group of international experts proposes to a) provide assurance of supply of reactor technology and nuclear fuel; b) accept a time-limited moratorium (of perhaps 5-10 years) on new uranium enrichment and plutonium separation facilities - at the very least for countries that do not currently have such technologies; c) establish a framework for multilateral management and control of the 'back end' of the fuel cycle (i.e. spent fuel reprocessing and waste disposal); and d) create a similar framework for multilateral management and control of the 'front end' of the fuel cycle (i.e. enrichment and fuel production). The effectiveness of nuclear verification depends on the extend of access to information and locations in a given country and inspections can only verify what countries declare. The expanded access provided by the Additional Protocol to safeguards agreements enables the Agency to verify possible undeclared activities however both safeguards agreements are focused on nuclear material and therefore the Agency's authority to investigate possible parallel weaponization activity is limited. In addition only 70 countries have the additional protocol on force. A dditional transparency measures' may be required as well as additional funding to support R and D on new technologies for detecting clandestine nuclear facilities and activity. An important step to address the nuclear

  4. Theoretical and experimental analysis of photonic structures for fluorescent concentrators with increased efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, Jan Christoph; Peters, Marius; Blaesi, Benedikt; Gombert, Andreas; Glunz, Stefan; Willeke, Gerhard [Fraunhofer Institute for Solar Energy Systems, Freiburg (Germany); Proenneke, Liv [Institut fuer Physikalische Elektronik, Universitaet Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart (Germany); Steidl, Lorenz; Zentel, Rudolf [Institut fuer Organische Chemie, Universitaet Mainz, Duesbergweg 10-14, 55128 Mainz (Germany); Rau, Uwe [IEF-5 Photovoltaik, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2008-12-15

    In this study we present a theoretical and experimental analysis of the application of photonic band stop filters on top of photovoltaic fluorescent concentrators in order to increase the photon collection efficiency. The light guiding effect of the fluorescent concentrator relies on total internal reflection. The escape cone of total internal reflection is their major loss mechanism. Our ray tracing simulation allows to calculate the beneficial effect of photonic band stop reflection filters, which reduce these losses, and to simulate the angular distribution of the light trapped in the concentrator. We present simulations of the optical properties of 1D and 3D photonic structures and how 3D structures are realized with colloidal opals. We also show that the application of a 1D photonic structure increases the efficiency of a real system by 20% relative. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Validation of DIAGNOdent laser fluorescence and the International Caries Detection and Assessment System (ICDAS) in diagnosis of occlusal caries in permanent teeth: an in vivo study.

    Science.gov (United States)

    Castilho, Lia S; Cotta, Fernanda V M D; Bueno, Audrey C; Moreira, Allyson N; Ferreira, Efigênia F; Magalhães, Cláudia S

    2016-04-01

    The aim of this in vivo study was to validate the DIAGNOdent laser fluorescence method and the International Caries Detection and Assessment System (ICDAS) for caries classification against the gold standard, histological examination, for detecting occlusal caries on permanent molars; the thresholds used were the outer enamel (D1), the inner enamel and outer third of the dentine (D2), and the inner two-thirds of the dentine (D3). Patients with non-impacted third molars (n = 43) were recruited from a university clinic. A trained examiner performed the examinations. After the teeth were extracted, the histological criterion was used to determine the severity of the lesions. Intra-examiner agreement (weighted kappa) for ICDAS was 0.60 and reliability (intraclass correlation coefficient) for DIAGNOdent was 0.968. The correlations with the histological reference were weak for DIAGNOdent (rs = 0.369) and moderate for ICDAS (rs = 0.515). The areas under the receiver-operating characteristics (ROC) curve at D1, D2, and D3 were 0.60, 0.69, and 0.91, respectively, for ICDAS and 0.55, 0.65, and 0.92, respectively, for DIAGNOdent. ICDAS and DIAGNOdent proved to be reproducible methods with similar performance in the detection of occlusal carious lesions in dentine. The ability of DIAGNOdent to detect initial enamel lesions was higher than that of ICDAS, but with low specificity. The usefulness of DIAGNOdent as an adjunct method for assessment of initial occlusal caries in permanent molars is questionable. © 2016 Eur J Oral Sci.

  6. "Contagion" between the emerging and developed capital markets: empirical evidence and reflections on the international portfolio diversification

    Directory of Open Access Journals (Sweden)

    Wagner Moura Lamounier

    2008-10-01

    Full Text Available In this research, we analyzed the short and long term interdependence and relationship between the stock indices of the major emerging capital markets and the major developed markets for the period 1995-2005. The aim was to verify the existence and the dynamics of the “contagion” between the markets, or if the occurrence of crises and changes in the behavior of a market would have impacts on the behavior of the others. In the development of the work, we applied the methodology of the Vector Error Correction Model (VEC. We found the presence of cointegrating relationships between the markets analyzed, but was able to see that, despite being cointegrated markets, investors could benefit from international diversification of portfolios. That’s because the speed of adjustment of the long-term ratio of cointegration between the markets was low for the period analyzed. Accordingly, investors would have the opportunity to reduce risk by diversifying their portfolios.

  7. An assessment of the importance ofexposure routes to the uptake and internal localisation of fluorescent nanoparticles in zebrafish (Danio rerio), using light sheet microscopy

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Ašmonaitė, G; Jølck, Rasmus Irming

    2017-01-01

    A major challenge in nanoecotoxicology is finding suitable methods to determine the uptake and localisation of nanoparticles on a whole-organism level. Some uptake methods have been associated with artefacts induced by sample preparation, including staining for electron microscopy. This study used...... light sheet microscopy (LSM) to define the uptake and localisation of fluorescently labelled nanoparticles in living organisms with minimal sample preparation. Zebrafish (Danio rerio) were exposed to fluorescent gold nanoparticles (Au NPs) and fluorescent polystyrene NPs via aqueous or dietary exposure...

  8. Activation of fluorescent protein chromophores by encapsulation.

    Science.gov (United States)

    Baldridge, Anthony; Samanta, Shampa R; Jayaraj, Nithyanandhan; Ramamurthy, V; Tolbert, Laren M

    2010-02-10

    Chromophores related to fluorescent proteins, when sequestered into the "octaacid" capsule, recover their fluorescence. The fluorescence recovery is related to the inhibition of torsional motions within the cavity, implicating the single-bond torsion as an important contributor to internal conversion within this important class of chromophores.

  9. Effects of acute O3 stress on PSII and PSI photochemistry of sensitive and resistant snap bean genotypes (Phaseolus vulgaris L.), probed by prompt chlorophyll "a" fluorescence and 820 nm modulated reflectance.

    Science.gov (United States)

    Salvatori, Elisabetta; Fusaro, Lina; Strasser, Reto J; Bussotti, Filippo; Manes, Fausto

    2015-12-01

    The response of PSII and PSI photochemistry to acute ozone (O3) stress was tested in a "model plant system", namely the O3 sensitive (S156) and O3 resistant (R123) genotype pairs of Phaseolus vulgaris L., during a phenological phase of higher O3 sensitivity (pod formation). The modulation of the photosynthetic activity during O3 stress was analysed by measuring gas exchanges, Prompt Fluorescence (PF, JIP-test) and 820 nm Modulated Reflectance (MR), a novel techniques which specifically detects the changes in the redox state of P700 and plastocyanin. The results showed that, coherently with genotypic-specific O3 sensitivity, the response of the two snap bean genotypes differed for the intensity and time of onset of the considered physiological changes. In fact, despite leaf injury and gas exchanges reduction appeared concurrently in both genotypes, S156 showed a PSII down regulation already after the first day of fumigation (DOF), and an enhancement of Cyclic Electron Flow of PSI after the second DOF, whereas R123 showed only slight adjustments until the third DOF, when the activity of both photosystems was down-regulated. Despite these differences, it is possible to distinguish in both genotypes an early O3 response of the photochemical apparatus, involving PSII only, and a following response, in which PSI activity and content are also modulated. The measurement of the MR signal, performed simultaneously with the PF measurements and the JIP-test analysis, has allowed a better understanding of the role that PSI plays in the O3 stress response of the S156/R123 model plant system. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. In situ ultrasound-assisted preparation of Fe3O4@MnO2 core-shell nanoparticles integrated with ion co-precipitation for multielemental analysis by total reflection X-ray fluorescence

    Science.gov (United States)

    Nourbala-Tafti, Elaheh; Romero, Vanesa; Lavilla, Isela; Dadfarnia, Shayesteh; Bendicho, Carlos

    2017-05-01

    In this work, a new analytical approach based on in situ ultrasound-assisted preparation of manganese dioxide coated magnetite nanoparticles (Fe3O4@MnO2 NPs) was applied for extraction and preconcentration of Ni, Cu, Zn, Tl, Pb, Bi and Se. The Fe3O4@MnO2 core-shell nanocomposite was synthesized by application of high-intensity sonication to an aqueous reaction medium in the presence of the target analytes, which are trapped during NPs formation. In this way, synthesis of the nanosorbent and extraction can be simultaneously accomplished within only 30 s. After the extraction step, the resulting Fe3O4@MnO2 NPs enriched with the target analytes were separated by an external magnetic field, so that filtration or centrifugation steps were unnecessary. A 10 μL aliquot of the solid phase was deposited onto a sample carrier (quartz reflector) and directly analyzed by total-reflection X-ray fluorescence (TXRF) without the need for an elution step. A comprehensive characterization of the Fe3O4@MnO2 NPs was carried out by transmission electron microscopy and TXRF. Detection limits ranged from 0.19 to 0.98 μg L- 1 depending on the analyte. Enrichment factors in the range of 402-540 were obtained. The repeatability expressed as relative standard deviation was around 1.7% (N = 5). The accuracy of the proposed method was assessed by analyzing the certified reference material BCR®-610 (groundwater). An effective, simple, rapid and sensitive procedure for multielemental analysis of water samples was accomplished.

  11. The influence of the solid waste disposal areas in Campinas city, Sao Paulo state (Brazil) on water quality: determination of metals using synchrotron radiation total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Bruna F.F., E-mail: bffaria@yahoo.com.br [Universidade Federal de Uberlandia (UFU), Uberlandia, MG (Brazil). Inst. de Ciencias Agrarias. Dept. de Engenharia Ambiental; Moreira, Silvana; Canteras, Felippe Benavente, E-mail: silvana@fec.unicamp.br, E-mail: felippe.canteras@gmail.com [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Dept. de Saneamento e Ambiente

    2013-07-01

    Among the many forms of waste disposal, landfills today are best suited to Brazilian conditions, this because their construction allows minimizing the negative effects of landfill gas and slurry produced. However, the confinement of pollutants from landfills is linked to its construction and operation and when the construction and/or is wrong they can endanger air, groundwater and surface waters qualities. Thus, the main objective of this study was to analyze the concentration of heavy metals in samples of groundwater, surface water and slurry coming from solid waste disposal locations in the city of Campinas, SP - Delta, Santa Barbara and Pirelli Landfills. The samples were analyzed at the Brazilian Synchrotron Light Laboratory using Synchrotron Radiation Total Reflection X-Ray Fluorescence technique (SR-TXRF). In Pirelli Landfill, the highest concentrations were observed in one of the wells located to downstream of the Landfill (in relation to the groundwater flux) - the monitoring well PM04, exceeding the intervention value defined by CETESB. For Santa Barbara landfill in one upstream monitoring well the concentrations of Ni, Mn, Pb and Cr, surpassed the maximum permissive values. The manganese in Landfill Delta showed to be higher in wells located downstream and 50% of the wells analyzed exceeded the maximum permissive value for groundwater samples. In the case of surface waters located in the vicinity of landfill sites, the metals that surpassed the maximum permissive values according the legislation in most of the points analyzed were Mn, Cu and Pb. For slurry samples collected in Delta Landfill, the average concentrations for Mn, Ni, Cu and Pb not exceeded the maximum permissive values during the period studied. Moreover for Santa Barbara the average concentration of Mn, Cu and Zn surpassed the permissive limits, as was observed for Mn in the Pirelli Landfill. (author)

  12. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

    Energy Technology Data Exchange (ETDEWEB)

    Wobrauschek, P., E-mail: wobi@ati.ac.at; Prost, J.; Ingerle, D.; Kregsamer, P.; Streli, C. [Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna (Austria); Misra, N. L. [Fuel Chemistry Division, Bhabha Atomic Research Centre (BARC), Mumbai 400085 (India)

    2015-08-15

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm{sup 2} active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  13. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

    Science.gov (United States)

    Wobrauschek, P.; Prost, J.; Ingerle, D.; Kregsamer, P.; Misra, N. L.; Streli, C.

    2015-08-01

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm2 active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  14. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence.

    Science.gov (United States)

    Wobrauschek, P; Prost, J; Ingerle, D; Kregsamer, P; Misra, N L; Streli, C

    2015-08-01

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm(2) active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  15. Fluorescence Spectra of Highlighter Inks

    Science.gov (United States)

    Birriel, Jennifer J.; King, Damon

    2018-01-01

    Fluorescence spectra excited by laser pointers have been the subject of several papers in TPT. These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by fluorescent emission. Here we examine the fluorescence spectra of highlighter inks using green and violet laser pointers. We use an RSpec Explorer spectrometer to obtain spectra and compare the emission spectra of blue, green, yellow, orange, pink, and purple highlighters. The website Compound Interest details the chemical composition of highlighter inks; in addition, the site discusses how some base dye colors can be combined to produce the variety commercially available colors. Spectra obtained in this study were qualitatively consistent with the Compound Interest site. We discuss similarities and differences between various highlighter colors and conclude with the relevance of such studies to physics students.

  16. An Action Research into International Masters Program in Practicing Management (IMPM: Suggesting Refraction to Complement Reflection for Management Learning in the Global Knowledge Economy

    Directory of Open Access Journals (Sweden)

    Tunc D. MEDENI

    2008-05-01

    Full Text Available International Masters Program in Practicing Management (IMPM is a collaborative effort by major business schools and corporations around the world, balancing practical and academic issues within pedagogy of “experienced reflection”. This action research into the IMPM aims to explain the IMPM and its importance for the global knowledge economy, as well as identify and improve the current limitations of the program. As a result, we hope to provide specific suggestions for the IMPM practice and general guidelines for business education. Our suggestions are based upon a framework of “refraction” that follows a methodology of action research and pluralistic knowledge science epistemology, a critique of management learning, and a literature review on (critical reflection, as well as our findings about the IMPM practice. Also, critically reviewing Mintzberg and other authors’ ideas on management learning and IMPM specifically supports our discussion in this paper.

  17. Total internal reflection quasiphase matching-based broadband second harmonic generation in a plane-parallel uniaxial crystal of lithium niobate

    Science.gov (United States)

    Barma, Minakshi Deb; Deb, Sumita; Saha, Ardhendu

    2018-01-01

    The present work analytically investigates the generation of broadband second harmonic (SH) using total internal reflection (TIR) quasiphase matching technique in a plane-parallel uniaxial crystal having optic axis nonparallel with respect to the horizontal base. A computer-aided simulation has been performed using lithium niobate as the nonlinear material to determine the possibility of generating broadband SH intensity when broadband fundamental laser radiation is allowed to undergo TIR inside the crystal. The simulated results indicate a peak conversion efficiency of 5.22% with a spectral bandwidth (BW) of 116 nm, centered at 2.258 μm in a 10-mm-long slab. The effect of variation in operating temperature, crystal length, crystal thickness, angle of deviation of optic axis, and angle of incidence of fundamental beam at the air-prism interface on efficiency and BW of resulting SH output has been studied.

  18. A comparison of the performance of a fundamental parameter method for analysis of total reflection X-ray fluorescence spectra and determination of trace elements, versus an empirical quantification procedure

    Science.gov (United States)

    W(egrzynek, Dariusz; Hołyńska, Barbara; Ostachowicz, Beata

    1998-01-01

    The performance has been compared of two different quantification methods — namely, the commonly used empirical quantification procedure and a fundamental parameter approach — for determination of the mass fractions of elements in particulate-like sample residues on a quartz reflector measured in the total reflection geometry. In the empirical quantification procedure, the spectrometer system needs to be calibrated with the use of samples containing known concentrations of the elements. On the basis of intensities of the X-ray peaks and the known concentration or mass fraction of an internal standard element, by using relative sensitivities of the spectrometer system the concentrations or mass fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass per unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements to be determined are calculated during fitting a modelled X-ray spectrum to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross-sections of a peat core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi-element standard solution.

  19. A Starting Point for Fluorescence-Based Single-Molecule Measurements in Biomolecular Research

    Directory of Open Access Journals (Sweden)

    Alexander Gust

    2014-09-01

    Full Text Available Single-molecule fluorescence techniques are ideally suited to provide information about the structure-function-dynamics relationship of a biomolecule as static and dynamic heterogeneity can be easily detected. However, what type of single-molecule fluorescence technique is suited for which kind of biological question and what are the obstacles on the way to a successful single-molecule microscopy experiment? In this review, we provide practical insights into fluorescence-based single-molecule experiments aiming for scientists who wish to take their experiments to the single-molecule level. We especially focus on fluorescence resonance energy transfer (FRET experiments as these are a widely employed tool for the investigation of biomolecular mechanisms. We will guide the reader through the most critical steps that determine the success and quality of diffusion-based confocal and immobilization-based total internal reflection fluorescence microscopy. We discuss the specific chemical and photophysical requirements that make fluorescent dyes suitable for single-molecule fluorescence experiments. Most importantly, we review recently emerged photoprotection systems as well as passivation and immobilization strategies that enable the observation of fluorescently labeled molecules under biocompatible conditions. Moreover, we discuss how the optical single-molecule toolkit has been extended in recent years to capture the physiological complexity of a cell making it even more relevant for biological research.

  20. Studies of particulate matter and heavy metals of urban air pollution, in Antananarivo City, Madagascar, using total reflection X-ray fluorescence; Application de la fluorescence X a reflexion totale a l'etude des matieres particulaires et des metaux lourds de la pollution de l'air dans la ville d'Antananarivo, Madagascar

    Energy Technology Data Exchange (ETDEWEB)

    Rakotondramanana, H.T.; Randriamanivo, L.V.; Andriambololona, R.; Rasolofonirina, M. [Institut National des Sciences et Techniques Nucleaires Madagascar (Madagascar-INSTN), (Madagascar)

    2003-06-01

    Classic X-ray fluorescence (XRF) analysis may be greatly improved by using total reflection X-ray fluorescence (TXRF) to study the size distribution of toxic elements, undesirable ones and PM{sub 10} in the aerosols of Antananarivo urban areas. The air sampler DICHOTOMOUS was used for sampling, with which two types of aerosols could be obtained: respirable aerosols or fine particles PM{sub 2.5} (aerodynamic diameter below 2.5 {mu}m) and inhalable or coarse particles PM{sub 2.5-10} (aerodynamic diameter from 2.5 {mu}m to 10 {mu}m). Samples were taken from six sites, namely Ambohidahy tunnel, Ambanidia tunnel, Andravoahangy, Soarano, Mahamasina and Ankorondrano. The results show the presence of elements such as sulfur (S), potassium (K), calcium (Ca), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), bromine (Br), rubidium (Rb), strontium (Sr), and lead (Pb) in the aerosols. Their concentrations are high in respirable particles. The 1.8 {mu}g.m{sup -3} mean concentration value of lead is higher than 0.5 {mu}g.m{sup -3} (World Health Organization adopted value), and than 1.5 {mu}g.m{sup -3} US EPA (United States Environmental Protection Agency) admissible maximum. Regarding the size distribution, PM{sub 2.5} are mainly enriched in lead. The same result may also be stated for PM{sub 10} with a 240 {mu}g.m{sup -3} mean concentration value, higher than 150 {mu}g.m{sup -3}, adopted by the two above-mentioned organizations. Therefore, the Antananarivo urban area is classified as saturated zone for both parameters (lead and particulate matter). The utilization of Mason's enrichment factors shows that the elements such as S, Cr, Cu, Zn, Br and Pb are from both natural and anthropogenic sources. Elements such as K, Ca, Ti, Mn, Fe and Sr originate from the soil. The zoning of the selected areas shows that the urban areas of Antananarivo are classified as saturated zone. Finally, data from the Lung Diseases Department from Main Hospital in