bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Near-Infrared and Raman Spectroscopy for the Determination of Chemical and Physical Properties of Naphtha
Authors: Ku Min-Sik , Chung Hoeil
Published: October 2003

Near-infrared (NIR) and Fourier transform (FT) Raman spectroscopy have been compared and evaluated for the quantitative analysis of naphtha with the use of partial least-squares (PLS) regression. Naphtha has been chosen for this purpose since it is a complex mixture of similar hydrocarbons; therefore, both spectroscopic methods can be evaluated with a complex sample of different concentration ranges and also a physical property. Six different chemical compositions [total paraffin, total naphthene (cycloalkane), total aromatic, C6 paraffin, benzene, and cyclopentane] and specific gravity (as a physical parameter) have been selected to evaluate both spectroscopic methods. PLS calibration models for each property have been developed by using both NIR and Raman spectra without spectral pretreatment. Both methods showed good correlation with the corresponding reference methods, but NIR provided the better calibration performance over Raman. The superior signal-to-noise ratio as well as spectral reproducibility of NIR led to the improved calibration performance even though Raman spectroscopy provided richer spectral information. The signal-to-noise ratio, reproducibility of measurement, and richness of spectral information should be simultaneously considered for proper selection of a spectroscopic method, especially for quantitative analysis.
Determination of Stoichiometry of Solutes in Molten Salt Solvents by Correlations of Relative Raman Band Intensities
Authors: Boghosian S. , Berg R. W.
Published: October 2003

Raman spectroscopy has been used to determine the stoichiometry of solute complexes in molten salts at high temperatures under static equilibrium conditions. A simple formalism is derived for correlating relative Raman band intensities with stoichiometric coefficients. The experimental procedures and sets of experiments required for establishing the stoichiometry are described. The proposed method was applied for studying the dissolution reactions of V2O5 in molten Cs2S2O7 and of Nb2O5 or MoO3 in molten K2S2O7 at temperatures in the range 430–700 °C: (1) V2O5 + nS2O72- (l) → X2 n- (l); (2) Nb2O5 + nS2O72- (l) → Y2 n- (l); (3) MoO3 + nS2O72- (l) → Z2 n- (l). It is shown that the solute complex species formed in the studied reactions have, respectively, the following stoichiometries: (1) n = 2, (VO)2O(SO4)44-; (2) n = 3, NbO(SO4)33-; (3) n = 1, MoO(SO4)22-.
Dehydroxylation of Aluminum (Oxo)Hydroxides Using Infrared Emission Spectroscopy. Part II: Boehmite
Authors: Frost Ray L. , Kloprogge J. Theo , Russell Shane C. , Szetu Jennifer
Published: October 2003

The dehydroxylation of boehmite has been studied by the application of infrared emission spectroscopy over the 200 to 750 °C temperature range. The dehydroxylation is followed by the loss of intensity of the hydroxyl stretching frequencies observed at 3478, 3319, and 3129 cm−1and by the loss of intensity of the hydroxyl deformation modes at 1140 and 1057 cm−1. Dehydroxylation starts at 250 °C and is complete by 450 °C. No difference was found between the synthetic and natural boehmite dehydroxylation. The hydroxyl stretching frequencies show a pronounced blue shift, while the hydroxyl deformation modes show a pronounced red shift. Infrared absorption bands were observed at 3413, 3283, and 3096 cm−1for the hydroxyl stretching frequencies and at 1161 and 1071 cm−1for the hydroxyl deformation frequencies. Low-frequency infrared absorption bands are observed at 749, 635, and 542 cm−1and infrared emission bands at 811, 716, 611, and 456 cm−1. The infrared emission low-frequency bands moved to higher frequencies upon thermal treatment. Spectral changes in the low-frequency bands confirm that dehydroxylation commenced at 250°C. Infrared emission spectroscopy allows the phase changes of the Al2O3–H2O alumina system to be studied in situ at the elevated temperatures.
Fluorescence Piroxicam Study in the Presence of Cyclodextrins by Using the PARAFAC Method
Authors: Martins José A. , Sena Marcelo M. , Poppi Ronei J. , Pessine Francisco B. T.
Published: October 2003

The nonsteroidal anti-inflammatory drug Piroxicam is of interest not only in pharmacology and therapeutics but also in structural dynamics. This drug in solution presents several equilibria that depend on its conformational structure and the medium. Piroxicam was studied by total fluorescence by using a chemometric method (parallel factor analysis or PARAFAC) to resolve its spectra. The addition of cyclodextrins can promote the encapsulation of some preferred Piroxicam species and more easily affect the spectral de-convolution. Because each species has a distinct spectrum as a function of the degree of encapsulation, a factorial fractional design (face-centered fractional cubic with a central sample) was considered for different cyclodextrins solutions. It was possible to identify a correlation between some spectra and the isomers and to reach some understanding of the spectroscopic behavior of the drug in cyclodextrin-containing hydrophilic solvents.
Constructing Surface Roughness of Silver for Surface-Enhanced Raman Scattering by Self-Assembled Monolayers and Selective Etching Process
Authors: Cao Yuehua , Li Ying-Sing
Published: October 2003

A new approach has been developed to roughen silver plates or foils for surface-enhanced Raman scattering (SERS). An aqueous solution consisting of potassium ferricyanide(III) and potassium thiocyanate was used as an etchant, which could selectively remove the unoccupied sites of the underlying silver. The resulting substrate was found to have a signal-enhancing effect for Raman scattering comparable to that produced by the oxidation-reduction cycle (ORC) technique. The etching time required to achieve optimal enhancement was very sensitive to the structure of adsorbed molecules in static etching. Scanning electron microscopy (SEM) allowed the characterization of surface roughness of the substrate. A step-by-step etching mechanism was revealed by the SEM images obtained from the substrate plates after different lengths of etching time, and a homogeneous distribution of the spheric silver features (diameters on the order of 100 nm) was observed throughout the surface after an optimal etching time. Electrochemical measurements of heterogeneous electron-transfer rates for different electrodes indicated an increase of surface area during etching, and an increase in the monolayer's barrier to electron transfer and the ion penetration upon re-immersion of the self-assembled monolayer (SAM) confined silver substrate in thiol solutions. The SER spectrum indicated that cyanide ion was adsorbed on the freshly formed silver surface. But the cyanide could be easily removed by re-immersing the electrode into the corresponding thiolate or sulfinate solution. Substrates subjected to UV exposure and water rinse were found to still be SERS-active and reusable for other analytes.
Static and Dynamic Infrared Linear Dichroic Study of a Polyester/Polyurethane Copolymer Using Step-Scan FT-IR and a Photoelastic Modulator
Authors: Wang Haochuan , Graff Darla K. , Schoonover Jon R. , Palmer Richard A.
Published: October 2003

Dynamic infrared linear dichroism (DIRLD) measurements of films of a thermo-plastic polyester/polyurethane random copolymer (Estane 5703, B. F. Goodrich) are reported. Step-scan Fourier transform infrared (FT-IR) is used for dynamic measurements, and a photoelastic modulator (PEM) is used to create broadband polarization modulation as the carrier frequency for the strain modulation. A novel modulation/demodulation strategy has been employed that simplifies the triple-modulation experiment into a double-modulation experiment; the theory is thoroughly discussed. Both static and dynamic dichroic absorption difference spectra have been measured on the prestretched polymer film. The results are of high signal-to-noise ratio (SNR) and clearly indicate the static and dynamic orientation of the transition dipole moments due to the tensile deformation. The dynamic orientation responses are primarily in phase with the perturbation. The orientation magnitudes of the infrared absorption bands are quantified and compared, and the orientations of the hard and soft domains are differentiated. To assist in the interpretation of the dynamically measured data, we also describe a static linear dichroic measurement using a wire-grid polarizer and FT-IR in the rapid-scan mode for a sample incrementally drawn until the point of breaking. The orientation functions of selected bands have been calculated, and the static results agree with the dynamic data, indicating the dependency of the dynamic orientation response on the preorientation state.
Spectral Data Analysis by Two-Dimensional Representation of Derivatives
Authors: Koashi Katsue
Published: October 2003

In this paper I propose a Di-Dj plot method that expresses pairs of ith and jth derivatives in a two-dimensional representation as a rational method to describe spectral waveforms. The basic concepts of the method are explained, and some examples of its applications are given to demonstrate the usefulness of the method in spectral analysis. First, I discuss the effects of plotting the correlations of derivatives of different powers—second vs. first and third vs. fourth—to separate adjacent bands, as well as the effect of adding a nonflat background to the spectrum. Next, a number of derivative correlation plots for Gaussian and Lorentzian shaped bands are described. Third, I show how the method can be used to determine the presence of an underlying band and how to extract the two bands from the original band. As examples of its applications, a waveform analysis of infrared spectra, the determination of the optimum cell pathlength for a water sample, and an analysis of temperature-dependent changes in a near-infrared (NIR) spectrum for water are discussed.
Characterization of a 22 mm Torch for ICP-AES
Authors: Horner Julie A. , Hieftje Gary M.
Published: October 2003

A 22 mm torch has been developed and characterized for use in inductively coupled plasma atomic emission spectrometry. A stability curve (radio-frequency power vs. outer-gas flow rate) was constructed for the modified torch which indicates that the larger torch can be operated at flow rates and powers similar to those for an 18 mm torch. Four operating parameters were optimized by means of a simplex algorithm. Several criteria for optimization were used, including net signal intensity for Ca(II); signal-to-background noise (S/NB) for Ca(II), Mg(II), and Fe(II); and the Mg(II)/Mg(I) line-intensity ratio. The results from these simplex optimizations are compared. Mg(II)/Mg(I) was used as the final criterion for optimization for both the 22 mm and the conventional 18 mm torches. Two-dimensional spatial images of the larger plasma were compared with those of a conventional plasma (18 mm) for a variety of plasma emission features. Detection limits were determined in two ways for a suite of analytes under conditions optimized for the Mg(II)/Mg(I) ratio. The 18 mm torch affords the better limits of detection by an averaged factor of 1.5 because its smaller volume gives a lower background level. Finally, nitrogen molecular-ion emission maps were collected from both the 22 mm and a conventional 18 mm plasma as an indicator of the degree of air entrainment in the plasma. Several spatial regions of the plasma have been evaluated on the basis of the local intensity of N2+ emission for their applicability for use in atomic emission and atomic mass spectrometry. The 22 mm torch shows a larger region in and around the central channel of low or zero N2+ emission and so may be better suited for sampling into a mass spectrometer.
Determination of the Drug Naphazoline in Pharmaceutical Preparations by Heavy Atom-Induced Room-Temperature Phosphorescence
Authors: Gutiérrez A. Fernández , Carretero A. Segura , Díaz B. Canãbate , Blanco C. Cruces
Published: October 2003

A simple, selective, and sensitive heavy atom-induced room-temperature phosphorimetric method (HAI-RTP) is described for the determination of naphazoline (NPZ) in pharmaceutical preparations. The phosphorescence signals are a consequence of intermolecular protection when analytes are, exclusively, in the presence of a heavy atom salt and sodium sulfite as an oxygen scavenger to minimize RTP quenching. This variable selection constitutes the basis of the HAI-RTP method for the determination of naphazoline (detection limit 43.5 ng/mL; 2.39% relative standard deviation at 500 ng/mL). The method has been applied to the analysis of pharmaceutical preparations.
Study of Fiber-Optic Probes for in vivo Medical Raman Spectroscopy
Authors: Shim Martin G. , Wilson Brian C. , Marple Eric , Wach Michael
Published: October 2003

Recent reports indicate that useful diagnostic information can be obtained from ex vivo tissue by using near-infrared Raman spectroscopy. A fiber-optic-based Raman system has been constructed that can obtain spectra in vivo from tissue, typically in less than 30 s. The spectral details are limited by the fluorescence and Raman signal generated in the silica delivery and collection fibers. In this study, fiber-optic probes that are designed to suppress these confounding signals have been characterized and compared with a probe constructed of unfiltered silica fiber. These suppressing probes used a novel design with “in-the-tip” filters, which also had optimized light collection efficiency. The spatial point response functions of the fibers were measured in air, water, and a tissue-simulating, optically turbid medium. Spectra from rabbit tissues were also collected with these probes to demonstrate their performance.
Quantitative Measurements in Scattering Media: Photon Time-of-Flight Analysis with Analytical Descriptors
Authors: Leonardi Lorenzo , Burns David H.
Published: October 2003

A method for the separate determination of the absorption and scattering properties from time-resolved photon distributions is described. Time distributions inherently contain information on the absorption and scattering processes. We have investigated the use of analytic descriptors such as derivatives and moments on the time distributions to facilitate the extraction of these optical coefficients. The descriptors were specifically chosen on the premise that circuits can be constructed to process the signal. Selection of the descriptor processing techniques and estimates of the absorption and scattering coefficients were made with the use of stepwise multilinear regression (STMLR). Estimates employing the analytical descriptors were evaluated experimentally with the use of photon time-of-flight in both transmittance and reflectance geometries. Results for both transmittance and reflectance indicate that the principal parameters, which describe the absorption and scattering coefficient, are the mean fall and rise times, respectively. Absorption estimates were primarily related to the trailing edge of the time profiles and scattering, the rising edge. The results suggest that practical instruments may be developed which would allow for a robust quantification in highly scattering media.
Post-Consumer Plastic Identification Using Raman Spectroscopy
Authors: Allen Valerie , Kalivas John H. , Rodriguez René G.
Published: October 2003

Raman spectroscopy is evaluated as a spectroscopic method for identification of common household plastics for recycling purposes. The methods of K-nearest neighbor (KNN), cyclic subspace regression (CSR), and library searching are compared for computerized plastic classification. Plastics studied consist of polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, low-density polyethylene, polypropylene, and polystyrene. With principal component analysis (PCA), visual distinction between the different plastics becomes possible. Correct class membership to all six plastic types is provided by KNN. To date, all development and uses of CSR have been based on building models for each prediction property analogous to the form of partial least-squares known as PLS1. Cyclic subspace regression is modified in this paper to also allow modeling of multiple properties, as does PLS2. The new form of CSR was able to correctly classify all six plastic types when seven-factor models were used. This paper reports that key observations made in comparing PCR to PLS1 are verified for the interrelationships of PCR and PLS2 models. Most notable is that even though PLS2 uses spectral responses and plastic identifications to form factors, PLS2 eigenvector weights are not much different from PCR eigenvector weights where PCR only uses spectral responses to form eigenvector weights. Library searching showed less significant results than KNN and CSR. Regardless of the identification approach, polyethylene samples could be identified as either being high density or low density with the use of Raman spectroscopy.
Quantitative Determination of Borophosphosilicate Glass Thin-Film Properties Using Infrared Emission Spectroscopy
Authors: Niemczyk Thomas M. , Zhang Songbiao , Franke James E. , Haaland David M.
Published: October 2003

We have completed an experimental study to investigate the use of infrared emission spectroscopy (IRES) for the quantitative analysis of borophosphosilicate glass (BPSG) thin films on silicon monitor wafers. Experimental parameters investigated included temperatures within the range used in the microelectronics industry to produce these films so that the potential for using the IRES technique for real-time monitoring of the film deposition process could be evaluated. The film properties that were investigated included boron content, phosphorus content, film thickness, and film temperature. The studies were conducted over two temperature ranges, 125 to 225 °C and 300 to 400 °C. The latter temperature range includes realistic processing temperatures for the chemical vapor deposition (CVD) of the BPSG films. Partial least-squares (PLS) multivariate calibration methods were applied to spectral and film property calibration data. The cross-validated standard errors of prediction (CVSEP) from the PLS analysis of the IRES spectra of 21 calibration samples each measured at six temperatures in the 300 to 400 °C range were found to be 0.09 wt % for B, 0.08 wt % for P, 3.6 nm for film thickness, and 1.9 °C for temperature. Upon lowering the spectral resolution from 4 to 32 cm−1 and decreasing the number of spectral scans from 128 to 1, we were able to determine that all the film properties could be measured in less than one second to the precision required for the manufacture and quality control of integrated circuits. Thus, real-time in situ monitoring of BPSG thin films formed by CVD deposition on Si monitor wafers is possible with the methods reported here.
Spectral Library Searching: Mid-Infrared versus Near-Infrared Spectra for Classification of Powdered Food Ingredient
Authors: Reeves James B. , Zapf Charles M.
Published: October 2003

The objective of this study was to determine the potential of using mid- or near-infrared diffuse reflectance spectra to construct food ingredient spectral libraries for product identification and checking. Samples (106) consisting of buttermilk, dehydrated onion, cheese and milk-egg powders, wheat flours, and two powdered seasonings were scanned “as is” (not diluted with KBr using diffuse reflectance) at 4 and 16 cm−1 resolution in the mid-infrared on a Digilab FTS-60 and a Perkin-Elmer Model 2000 and in the near-infrared on an FTS-60 (4 and 16 cm−1 resolution) and NIRSystems Model 6500 scanning monochromator (10 nm bandwidth). A custom-made sample transport device was used on the FTS-60, a rotating sample cup on the NIRSystems 6500, and a stationary cell for the Perkin-Elmer 2000. Every third sample of each group was used as a test sample and searched against a library containing the remaining samples. Results showed that only full spectrum based searches with the use of Euclidian distance or correlation (with or without a first derivative) were useful. All unknowns were correctly classified by using near-infrared spectra generated on either the scanning monochromator or the FTS-60 (4 cm−1 resolution) or by using any of the mid-infrared spectra. Results demonstrated that near- or mid-infrared spectral libraries of powdered food ingredients can be used for product identification and checking.
Nonintrusive Analysis of Chemical Agent Identification Sets Using a Portable Fiber-Optic Raman Spectrometer
Authors: Christesen Steven , Aciver Brian M , Procell Lawrence , Sorrick David , Carrabba Michael , Bello Job
Published: October 2003

A portable fiber-optic Raman system comprising a diode laser, echelle spectrograph, charge-coupled device (CCD) detector, and filtered fiber-optic probe has been used to analyze chemical agents and other toxic chemicals in sealed glass containers. These containers include ampoules and bottles that are contents of chemical agent identification sets (CAIS) developed for use in training military personnel in chemical agent identification, safe handling, and decontamination. Real-time nonintrusive analysis of these sets is required so that the items containing chemical agents can be identified for proper disposal. This paper details the laboratory measurement of Raman spectra of CAIS chemicals, the determination of detection limits for mustard gas and lewisite in chloroform, and the analysis of CAIS items in the field.
Study of Cell Degranulation with Simultaneous Microscope Imaging and Capillary Electrophoresis
Authors: Su Hui , Yeung Edward S.
Published: October 2003

The physical release of single granules from individual rat peritoneal mast cells (RPMCs) was monitored by video recording of the degranulating cells by a high-resolution charge-coupled device (CCD) microscope system. The bright granular core disappears from the image as the vesicular content is dissolved on contact with the extra-cellular fluid. After a fixed time delay, the exocytotic product, serotonin, was detected by capillary electrophoresis coupled with laser-induced native fluorescence (LINF-CE). The timing of the two events is mostly correlated, which supports a fast release mechanism of the granular products.
Development of a Filtering Technique for Planar Laser-Induced Fluorescence of the CH Radical with Diagonal Excitation/Observation
Authors: Musculus Mark P. , Foster David E.
Published: October 2003

A computational design tool has been developed and applied to a new fluorescence filtering scheme for the CH A2Δ↔X2π transition, which uses diagonal excitation and observation to provide the highest possible excitation and emission strengths in systems with high quenching. A holographic notch filter is proposed to reject elastic scatter while a 10 nm bandpass filter isolates CH fluorescence from other emissions. The computer simulation of the fluorescence process was employed to determine the combination of filters and excitation wavelengths that provided the highest fluorescence signal. Optimum filter configurations were determined for a spectrum of pressures, temperatures, and quenching environments. The analysis shows that this technique is best suited to high-pressure environments where saturation is not possible, and the signal strength of this diagonal excitation/observation technique in such environments is at least an order of magnitude greater than that for previous off-diagonal techniques.
Solid-Matrix Fluorescence and Phosphorescence and Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons with Hydrophobic Paper
Authors: Ackerman Amanda H. , Hurtubise Robert J.
Published: October 2003

Solid-matrix fluorescence (SMF) and solid-matrix phosphorescence (SMP) have been used in conjunction with solid-phase microextraction to characterize mixtures of polycyclic aromatic hydrocarbons (PAHs) isolated from water. Whatman 1PS paper was used to extract the PAH from water, and then the isolated PAHs were directly identified on the paper by obtaining SMF and SMP spectra. The SMF and SMP properties of 10 PAH were obtained, and the PAHs in a two-component mixture, a three-component mixture, and a four-component mixture were easily identified by a combination of SMF and SMP. No external heavy atom was needed to acquire the SMP data. Benzo[ e]pyrene gave a limit of detection of 6.2 pg/mL with SMP, and with SMF benzo[ a]pyrene gave a limit of detection of 19 pg/mL.
NMR Diffusion and Relaxation Study on Ibuprofen—HSA Interaction
Authors: Luo Ren-Sheng , Liu Mai-Li , Mao Xi-An
Published: October 2003

NMR diffusion and relaxation measurements were applied to study the ibuprofen–protein interaction by changing the drug concentration in solutions containing 0.1 M human serum albumin (HSA). On the basis of the assumption that the drug molecules undergo fast exchange between the binding and free states, the association constant, Ka, for drug–HSA complexes is found to be about 60, and the number of binding sites, n, is about 50. The small association constant and the big binding site number suggest weak interactions between ibuprofen and HAS.
Interactions between Methylene Blue and Sodium Dodecyl Sulfate in Aqueous Solution Studied by Molecular Spectroscopy
Authors: Carroll Mary K. , Unger Marc A. , Leach Andrew M. , Morris Melissa J. , Ingersoll Christine M. , Bright Frank V.
Published: October 2003

The interactions of methylene blue (MB, a cationic redox indicator and biological stain) and sodium dodecyl sulfate (SDS, a micelle-forming, anionic surfactant) in aqueous solution have been examined by using Rayleigh scattering, UV-visible absorption, and fluorescence spectroscopy. At SDS concentrations significantly below the critical micelle concentration (cmc), MB forms noncovalent dimers and aggregates with SDS that scatter light but do not fluoresce. For solutions containing 1 μM MB and < 3–5 mM SDS, shifts in the absorption spectrum characteristic of the formation of MB H-aggregates are noted. There appears to be little effect on the fluorescence emission spectrum, indicating that these MB aggregates do not fluoresce appreciably. At and above the known SDS cmc, MB is observed to interact with the micelles. The MB excited-state fluorescence lifetime (380 ps) remains constant until SDS micelles form, then increases to 615 ps. The MB rotational reorientation time similarly increases from 105 to 500 ps between 6 and 8 mM SDS. This finding suggests that the MB is encountering, on average, a microenvironment in the SDS micelles that is 5-fold more viscous than liquid water or the molar volume of the MB/SDS species that is reorienting is 5-fold larger than MB in water.
On the Weak Intrinsic Luminescence from Paclitaxel Dissolved in Nonelectrolyte Solvents
Authors: Pandey Siddharth , Baker Gary A. , Kane Maureen A. , Bright Frank V.
Published: October 2003

Paclitaxel, a diterpene natural product from the Pacific Yew tree, Taxus brevifolia, has emerged as a promising chemotherapeutic agent for treating solid tumors. We report here on the electronic absorbance and fluorescence spectra, fluorescence quantum yield, and excited-state fluorescence intensity decay kinetics of paclitaxel dissolved in several nonelectrolyte solvents. The results of these experiments show that the paclitaxel absorbance spectra are a function of paclitaxel concentration, consistent with concentration-dependent paclitaxel association. The paclitaxel molar absorptivity, fluorescence quantum yield, and radiative and nonradiative decay rates are all consistent with the excited state being of an ( n, π*) type. We propose that this observation arises from one or both of the phenyl–C = O moieties in paclitaxel. To the best of our knowledge, this paper represents the first comprehensive report on the intrinsic fluorescence from any member of the taxane family.
Experimental Technique for Quantitative IR Studies of Highly Absorbing Substances at High Temperatures and Pressures
Authors: Gorbaty Yu. E. , Bondarenko G. V.
Published: October 2003

A new high-temperature/high-pressure IR cell with a changeable pathlength is described. The pathlength can be varied immediately during a run at high pressure and temperature with a driving mechanism attached to the body of the cell. This arrangement presents the possibility of avoiding most of the common and specific errors connected with intensity measurements in the difficult case of highly absorbing substances. The cell can be used up to 780 K at a pressure of 100 MPa. The algorithms of data processing and examples of representative spectra of water are also discussed.
Interpretation of the Structure of Poly(Ethylene Terephthalate) by Dynamic FT-IR Spectra
Authors: Wang Yanxiang , Lehmann Stephan
Published: October 2003

Poly(ethylene terephthalate) (PET) was studied by the technique called dynamic infrared spectroscopy with the use of digital signal processing. The dynamic infrared signals of PET were correlated with the reorientation movement of functional groups and the deformation of internal coordinates, which depend upon the morphology of the sample. With the use of this novel approach, it is demonstrated that the internal coordinate change of the trans C–O bond plays an important role in the macroscopic deformation of oriented PET; the reorientation movement is differentiated in the case of unoriented PET, where the phenyl ring contributes more in such a process.
Resonance Raman Microspectroscopy of Normal Erythrocytes and Plasmodium Berghei-Infected Erythrocytes
Authors: Ong C. W. , Shen Z. X. , Ang K. K. H. , Kara U. A. K. , Tang S. H.
Published: October 2003

Resonance Raman microspectroscopy has been applied to study normal and Plasmodium berghei-infected mouse erythrocytes. The spectra of these two types of samples can be distinguished by the CaNCa deformation mode band at 747 cm−1 for the normal erythrocytes and at 754 cm−1 for the infected erythrocytes. It is believed that this difference in the spectra is due to the presence of haemozoin in the parasite, as a result of the polymerization of haem. The spectra obtained for the normal erythrocytes are due to the porphyrin group in the haemoglobin, whereas the spectra for the infected erythrocytes are due to those in the haemozoin. The spectral difference between the normal and infected erythrocytes enables us to identify the infected cells in the trophozoite or schizont stage from the normal cells. When the normal erythrocytes are subjected to high laser power, photoreduction of the sample occurs, and the spectra of these erythrocytes correspond to the spectra of deoxy Hb.
Quantitative Analysis of Agrochemical Formulations by Multivariate Spectroscopic Techniques
Authors: Almond Matthew J. , Knowles Stephen J.
Published: October 2003

Quantitative multivariate Fourier transform infrared (FT-IR) analysis has been compared with conventional gas chromatography and FT-Raman spectroscopy for the analysis of mixtures containing the organophosphate insecticide chlorpyrifos. Mid-IR spectra were recorded with the use of a ZnSe attenuated total reflectance (ATR) cell; Raman spectra were recorded on samples contained in glass sample bottles. Simple homogeneous solutions in either trimethyl-pentane or the commercial complex aromatic solvents Solvesso 100 or Solvesso 150 give results by FT-IR spectroscopy which are of a quality similar to those obtained by a conventional gas chromatographic technique. It is found that the multivariate FT-IR approach gives a rapid indication of the presence of impurities in the mixture, e.g., of surfactants or of the thermal degradation product 3,5,6-trichloro-2-pyridinol. Chlorpyrifos may be determined in the presence of its analog chlorpyrifosmethyl, but not if it is at a concentration that is too low relative to the analog. Variations in the spectral data on changing the temperature have been successfully modeled in terms of variations in the refractive index and density of the solutions. Multivariate FT-Raman spectroscopy appears less applicable to the formulation containing the aromatic solvent systems investigated, largely because the solvents used are too strongly scattering.
Spectrometric Temperature Measurement Using a Zinc Selenide-Based Fiber-Optic Sensor
Authors: White Shawn R. , Nave Stanley E.
Published: October 2003

An extrinsic fiber-optic sensor for temperature monitoring based on the spectral shift of ZnSe has been developed. The calibration model is based on wavelength position data rather than intensity, eliminating the need for measurement of the input light intensity and making it robust with respect to lamp and detector fluctuations. The wavelength accuracy necessary to obtain quality results with this method was achieved on a low-cost spectrometer by combining the sensor output with light from a mercury lamp that enabled realtime correction data to be acquired simultaneously with the spectral shift of the ZnSe. The results on this economically priced system were similar to those from a more expensive, more wavelength stable spectrometer that did not require wavelength correction. In both cases, the standard error of prediction (SEP) for temperatures in the 25–70 °C range was initially around 0.2 °C. After two weeks, the SEP increased to around 0.4–0.5 °C.
Polarization-Based Sensing with a Self-Referenced Sample
Authors: Lakowicz Joseph R. , Gryczynski Ignacy , Gryczynski Zygmunt , Tolosa Leah , Dattelbaum Jonathan D. , Rao Govind
Published: October 2003

We describe a new method of fluorescence sensing based on fluorescence polarization. The sensor consists of two compartments, both of which contain the sensing fluorophore. One side of the sensor contains a constant concentration of analyte, and the other contains the unknown concentration. Emission from both sides is observed through polarizers, with the polarization from the sample being rotated 90° from that of the reference. Changes in the fluorescence intensity of the sample result in changes in the measured polarization for the combined emission. We show that this approach can be used to measure glucose and calcium using fluorophores which show analyte-dependent intensity changes, and no change in the spectral shape. Only a single fluorophore is required, this being the sensing fluorophore in both sides of the sensor. We also show that polarization sensing of glucose and calcium can be performed with visual detection of the polarization. In this case the only electronic component is the light source. These simple schemes can be used with a variety of analytes. The only requirement is a change in fluorescence intensity in response to the analyte.
Influence of Anomalous Dispersion on the ATR Spectra of Aqueous Solutions
Authors: Max Jean-Joseph , Chapados Camille
Published: October 2003

Transmission spectra of aqueous solutions are difficult to obtain because in the 3 μm infrared region, the high absorptivity of water requires the use of thin films. In contrast, attenuated total reflectance (ATR) spectra of aqueous solutions, not requiring thin films, are easily obtained. Unfortunately, compared to measurements made by transmission, ATR measurements cause some variation in the band shape due to the anomalous dispersion (AD) effect. To evaluate these variations, we studied pure water and KCl aqueous solutions. We then compared the ATR spectra of both substances with the real and imaginary refractive index spectra calculated by using the Kramers–Krönig relation. As long as the proper material is used in the ATR cell and the concentration of water is not significantly decreased, then the IR-ATR measurements directly reflect the chemistry of the sample.
Generalized Two-Dimensional Fourier Transform Infrared Multiple-Angle Attenuated Total Reflection Spectral Depth-Profiling Analysis of Multilayer Samples
Authors: Nishikawa Yuji
Published: October 2003

This paper reports the application of a generalized two-dimensional (G2D) correlation method in multiple-angle single-reflection attenuated total reflection (ATR) spectral depth-profiling analysis of multilayer samples. In this method, ATR spectra at different incident angles are used to generate two-dimensional (2D) correlation spectra. The relative spatial interactions of correlated signals are then determined from the signs of the corresponding contours of the asynchronous map. In order to apply this method to multilayer samples, effects of dispersion in refractive indices of materials which create pseudo-contours were first investigated with simulated ATR spectra. Model ATR spectra were generated from conventional antisymmetric linear combinations of the Lorentzian functions. The use of Ge ATR crystals minimizes the pseudo-contours and allows the method to be successfully applied to actual multilayer samples. A 0.1 μm thick gelatin layer on a polyester film and a 0.2 μm thick polycarbonate layer on the gelatin/polyester film were investigated as actual model samples. In the model samples, although the layers were thin, the relative depth of each layer was easily determined.
Infrared Emission Spectroscopic Study of Some Natural and Synthetic Paragonites
Authors: Kloprogge J. Theo , Frost Ray L.
Published: October 2003

The infrared emission spectra of a synthetic paragonite have been compared to natural paragonites from Monte Campione (Switzerland) and Williamstown (Australia). The OH stretching region is characterized by a silanol band around 3745 cm−1, two Al–OH stretching bands around 3650 and 3627 cm−1, and a water band around 3450 cm−1. The low-frequency region is characterized by bands at 1185, 1075, 993, 917, 883, 819, 803, 750, 725, 622, 545, and 486 cm−1 ascribed to different Si–O stretching, Al–OH libration and bending, and Si–O and Si–O-AlVI bending modes. The natural paragonites show minor differences in band positions. In the spectra of the paragonite from Williamstown (Australia), bands at 883 and 725 cm−1 are missing, while a new band is observed at 521 cm−1 and the Si–O stretching bands are shifted towards higher wavenumbers. This result is ascribed to the presence of a muscovite component in the crystal structure of the paragonite, as is possible in the continuous compositional series muscovite–paragonite. Heating causes the dehydroxylation of the paragonite, as is evidenced by broadening, a shift towards lower wavenumbers, and a diminishing intensity of the bands associated with the various OH modes. No new bands were observed indicating the restructuring of the octahedral layer.
Information dissemination and use: Critical components in occupational safety and health
Authors: Schulte P.A. , Okun A. , Stephenson C.M. , Colligan M. , Ahlers H. , Gjessing C. , Loos G. , Niemeier R.W. , Sweeney M.H.
Published: October 2003

Background

Information dissemination is a mandated, but understudied, requirement of occupational and environmental health laws and voluntary initiatives. Research is needed on the factors that enhance and limit the development, transfer, and use of occupational safety and health information (OSH). Contemporary changes in the workforce, workplaces, and the nature of work will require new emphasis on the dissemination of information to foster prevention.

Methods

Legislative and regulatory requirements and voluntary initiatives for dissemination of OSH information were identified and assessed. Literature on information dissemination was reviewed to identify important issues and useful approaches.

Results

More than 20 sections of laws and regulations were identified that mandated dissemination of occupational and environmental safety and health information. A four‐stage approach for tracking dissemination and considering the flow of information was delineated. Special areas of dissemination were identified: the information needs of the changing workforce, new and young workers; small businesses; and workers with difficulty in understanding or reading English.

Conclusions

We offer a framework for dissemination of OSH information and underscore the need to focus on the extent to which decision‐makers and others receive and use such information. More solid data are also needed on current investments in disseminating, diffusing and applying OSH information and on the utility of that information. Am. J. Ind. Med. 44:515–531, 2003. Published 2003 Wiley‐Liss, Inc.
Utility of a routine medical surveillance program with benzene exposed workers
Authors: Bogadi‐Šare Ana , Zavalić Marija , Turk Rajka
Published: October 2003

Background

A medical surveillance program of benzene‐exposed workers has to be established in such a way as to observe early signs of benzene‐induced cytopenia, pancytopenia, or leukemia. This study evaluates the utility of routine medical survey applied to benzene‐exposed workers by analyzing the hematological, immunological, and cytogenetic assay results.

Methods

The results of a previous study of hematological, immunological, and cytogenetic assays in benzene‐exposed workers (up to 15 ppm) are used to discuss medical surveillance program by defining the relationship between various benzene exposure concentrations and toxic endpoints.

Results

Exposure to benzene concentration lower than 5 ppm does not produce any abnormal hematological measurements. For benzene cumulative exposure above 100 (ppm‐years), some blood indices [mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), band neutrophils] show significant differences in comparison to the control group. The incidence of dicentric chromosomes was higher and the level of B‐lymphocytes was lower even with workers exposed to 5 ppm of benzene; correlation with exposure indicators was not found.

Conclusions

The results suggest that peripheral blood indices, although not sensitive enough, are still the most suitable parameters in a health surveillance program applied to benzene‐exposed workers. B‐lymphocytes could be a promising indicator of the benzene‐induced damage. Cytogenetic tests did not prove to be suitable. Further investigation of useful screening tests for health surveillance program of benzene‐exposed workers is still required. Am. J. Ind. Med. 44:467–473, 2003. © 2003 Wiley‐Liss, Inc.
Risk factors in health, work environment, smoking status, and organizational context for work disability
Authors: Lund Thomas , Csonka Agi
Published: October 2003

Background

This study examines the associations between health, work environment exposures, smoking status, and organizational context and work disability.

Methods

In a sample of 3,318 Danish employees, respondents were interviewed by telephone in 1995 about health, work environment, smoking status and organizational context of the workplace. In 1997, a follow‐up to assess employment status was conducted using The Statistical Register of Transfer Payments, Statistics Denmark.

Results

Work disability is predicted by work environment, smoking status of the individual employee, and by organizational level factors at the workplace. Although poor mental health, chronic bronchitis or musculoskeletal symptoms in neck or shoulders were equally distributed at baseline among type of company, the 2‐year incidence of work disability was higher in traditionally organized workplaces than in flexibly organized workplaces.

Conclusion

The study suggests a potential for reducing health‐related work disability from work through flexible organization of the workplace. Am. J. Ind. Med. 44:492–501, 2003. © 2003 Wiley‐Liss, Inc.
Biological indices of kidney involvement in personnel exposed to sevoflurane in surgical areas
Authors: Trevisan Andrea , Venturini Matteo Borella , Carrieri Mariella , Giraldo Monica , Maccà Isabella , Perini Milena , Scapellato Maria L. , Virgili Annalisa , Bartolucci Giovanni B.
Published: October 2003

Background

Fluoride, a main metabolite, and one degradation product of sevoflurane (SEV), called Compound A, are known to cause kidney effects in experimental animals. Other than in volunteers and patients, no research is available on exposed workers. The possible effects on the kidney in workers exposed in surgical areas were studied.

Methods

Subjects exposed to SEV and nitrous oxide (N2O) in surgical areas (N = 61) using open (N = 25) or semi‐closed (N = 36) circuits were submitted to biological monitoring. The same biological indices were determined in 43 controls also. Sevoflurane (SEVU), nitrous oxide (N2OU), total urinary proteins (TUP), N‐acetyl‐β‐D‐glucosaminidase (NAGU), and glutamine synthetase (GSU) were measured in urine.

Results

The mean values of environmental exposure were 31.3 ppm (range 0.9–111.6 ppm) for N2O and 0.28 ppm (range 0–1.88 ppm) for SEV. Exposed subjects had significantly higher excretion of TUP; a higher, not significant, excretion of GSU was also observed in subjects using open circuits. A significant correlation was found in all exposed subjects between NAGU and SEVU (r = 0.303, P < 0.05), GSU and N2OU (r = 0.382, P < 0.01) and, especially, GSU and SEVU (r = 0.650, P < 0.001). These correlations appeared to be influenced by the use of open circuits; infact, NAGU was well correlated to N2OU (r = 0.770, P < 0.001) and SEVU (r = 0.863, P < 0.001); GSU to N2OU (r = 0.468, P < 0.05) and SEVU (r = 0.735, P < 0.001).

Conclusions

Results show that no relevant effect on the kidney is present for the levels of exposure studied. Nevertheless, correlation between dose and response urinary indices supports that SEV, other than N2O, may influence kidney function, especially when open circuits are used. Am. J. Ind. Med. 44:474–480, 2003. © 2003 Wiley‐Liss, Inc.
Association of expired nitric oxide with urinary metal concentrations in boilermakers exposed to residual oil fly ash
Authors: Kim Jee Young , Hauser Russ , Wand Matthew P. , Herrick Robert F. , Houk R.S. , Aeschliman David B. , Woodin Mark A. , Christiani David C.
Published: October 2003

Background

Exposure to metal‐containing particulate matter has been associated with adverse pulmonary responses. Metals in particulate matter are soluble, hence are readily recovered in urine of exposed individuals. This study investigated the association between urinary metal concentrations and the fractional concentration of expired nitric oxide (FENO) in boilermakers (N = 32) exposed to residual oil fly ash (ROFA).

Methods

Subjects were monitored at a boiler overhaul site located in the New England area, USA. FENO and urine samples were collected pre‐ and post‐workshift for 5 consecutive workdays. Metals investigated included vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), and lead (Pb).

Results

The median FENO was 7.5 ppb (95% CI: 7.4–8.0), and the median creatinine‐adjusted urinary metal concentrations (μg/g creatinine) were: vanadium, 1.37; chromium, 0.48; manganese, 0.30; nickel, 1.52; copper, 3.70; and lead, 2.32. Linear mixed‐effects models indicated significant inverse exposure–response relationships between log FENO and the log‐transformed urinary concentrations of vanadium, manganese, nickel, copper, and lead at several lag times, after adjusting for smoking status.

Conclusions

Urine samples may be utilized as a biomarker of occupational metal exposure. The inverse association between FENO and urinary metal concentrations suggests that exposure to metals in particulate matter may have an adverse effect on respiratory health. Am. J. Ind. Med. 44:458–466, 2003. © 2003 Wiley‐Liss, Inc.
Non‐fatal injuries in the West Virginia logging industry: Using workers' compensation claims to assess risk from 1995 through 2001
Authors: Bell Jennifer L. , Helmkamp James C.
Published: October 2003

Background

The logging industry has a high rate of both fatal and non‐fatal injuries in comparison to other industries, and plays a vital role in WV's economy.

Methods

Workers' compensation (WC) injury claims and employment data were summarized to examine patterns and rates of non‐fatal logging injuries in WV from 1995 through 2001.

Results

The average annual rate of injury claims was 16.0 per 100 workers per year with rates remaining relatively steady over the 7‐year study period. The highest rates of injury were a result of being struck by an object, typically trees, snags, or logs.

Conclusions

WV loggers most often file injury claims as a result of being struck by trees and tree parts, snags, and logs. Assessment of risk is a critical component in helping regulators, researchers, and the logging industry develop viable prevention strategies to reduce the incidence and severity of logging‐related injuries. Am. J. Ind. Med. 44:502–509, 2003. Published 2003 Wiley‐Liss, Inc.