bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Kuwait Crudes. II. Structural Analysis of Asphalts and Their Fractions by Nuclear Magnetic Resonance
Authors: Al-Farkh Yusuf A. , El-Rayyes Nizar R. , Al-Hajjar Farouk H. , Al-Zaid Khairya A.
Published: September 2005

Nuclear magnetic resonance methods were used for the determination of average structural formulae and formula weights of the saturate, naphthene-aromatic, and polar-aromatic fractions separated from asphalts by elution adsorption chromatography. The average formula weights are compared to molecular weights, showing fair agreement in the majority of cases. The more polar fractions of one asphalt had molecular weights up to 4 times the formula weights, while the less polar fractions had molecular weights in excellent agreement with formula weights. The aromaticity, the degree of substitution, the nonaromatic carbon in naphthenic rings, and the atomic hydrogen/carbon ratio of the fractions were discussed.
Matrix-Isolation Studies and Ring Conformation of 1,3-Dithietane
Authors: Kalasinsky V. F. , Block E. , Powers D. E. , Harris W. C.
Published: September 2005

The infrared and Raman spectra of 1,3-dithietane have been recorded with the sample in the solid state and trapped in an argon matrix at 18K. The number of coincidences between the infrared and Raman spectra of the matrix-isolated sample is consistent with C2v molecular symmetry in which the ring has a puckered conformation. In the solid state a number of bands disappear upon annealing, and the observed mutual exclusion for the annealed solid can be interpreted in terms of D2h, symmetry. Whereas the matrix probably represents the “free” molecule, the planarity of the ring in the annealed solid can be attributed to crystal packing.
The Emission Spectrographic Determination of Boron in Silicate Materials
Authors: Dale L. S.
Published: September 2005

A procedure is described for the spectrographic determination of boron in silicate materials such as soils and coal ash. The method is based on the use of a lithium fluoride-graphite buffer with germanium as internal standard. A correction for SiO band interference is made. Standardization is facilitated using boron-in-graphite standards. The precision of the method is ±10% and the accuracy is better than 15%. The limit of detection is 10 μg g−1.
Interpretation Coherent Anti-Stokes Raman Spectroscopy (CARS) Spectral Profiles
Authors: Shaub W. M. , Lemont S. , Harvey A. B.
Published: September 2005

CARS spectral profiles are functionally described by the variation of the square of the total third-order, nonlinear susceptibility with the anti-Stokes frequency shift. This inherent, squared susceptibility signal dependence, when weighted by an experiment dependent convolution, produces a CARS spectral profile which is a problem specific to the experiment design.
Short-Time Radiative Processes in Exploding Metal Foil Plasmas
Authors: Sacks R. D. , Ling C. S.
Published: September 2005

Spacially and temporally resolved spectra are described from explosions of Al foil strips in Ar at 100 and 700 Torr. Spectra were obtained photographically with a time resolution of 0.3 μs using a rotating mirror streaking camera. Measurements were made at 1, 2, 5, 10 and 15 mm above the foil surface with a spacial resolution of 0.1 mm. The early appearance of Ar ion lines for explosions in Ar at 100 Torr implies initial current conduction following foil vaporization via dielectric breakdown of the Ar. At 700 Torr, the complete absence of radiation from Ar ion lines suggests that gas-phase current conduction begins by dielectric breakdown of the metal vapor. The short duration of Ar ion radiation in any observation zone at 100 Torr coupled with the first appearance of radiation from metallic species during the period of decaying Ar intensity implies that the metal vapor is collisionally excited and ionized as it passes through the Ar current sheath. From the results of these studies, a dual-channel, photoelectric, gated integration procedure was used to obtain greater analysis line/background ratios. A two- to four-fold increase in line/background ratios is obtained when radiation from 15 mm above the foil is integrated during the interval from 25 to 125 μs after foil vaporization.
Characterization of a Charge-Coupled Device Photoarray as a Molecular Absorption Spectrophotometric Detector
Authors: Ratzlaff Kenneth L. , Paul Steven L.
Published: September 2005

Recently there has been a great deal of interest in the use of solid-state multichannel detectors as sensors for rapid-scan spectroscopy. The charge-coupled device (CCD) photoarray, not previously characterized for this application, is described. The unit has 1728 elements, arranged linearily, which integrate light over the same time frame; the photo signals are then read serially. The CCD was found to produce signals which are linear with both intensity and integration time. The dark signal at −10°C is 0.1% of saturation for a 10 ms integration time, and the noise level is less than 0.08% of saturation. The wavelength response is in the visible region. The application for rapid-scan spectrophotometry is also discussed.
The Determination of T-2 Toxin, Diacetoxyscirpenol, and Deoxynivalenol in Foods and Feeds
Authors: Stahr H. M. , Kraft A. A. , Schuh Max
Published: September 2005

A method is presented for the analysis of mycotoxins using acetonitrile (90) water (10) extraction, petroleum ether defatting and ferric gel decolorization, chloroform partitioning, and a 1000-fold concentration. Gas chromatography and thin layer chromatography are used to separate and analyze the three most common thichothecene mycotoxins. The analysis has been applied to animal feeds, human foods, and animal tissues. Confirmation of the presence of the mycotoxins is made by IR, NMR, and/or mass spectrometric analysis and/or the chicken embryo test. The sensitivity of the method is 1 ppm for the three trichothecenes, the level of biological effectiveness. The gas chromatographic analysis technique is sensitive to 10 ng of each mycotoxin; the thin layer analysis is sensitive to 100 ng of each compound. Mass spectra may be obtained from 100 ng of each toxin taken from a thin layer chromatogram and the LD50 for chicken embryos is 100 ng/egg for T-2 toxin and diacetoxyscirpenol. Vomitoxin (deoxynivalenol) has not been subjected to the chicken embryo test due to the lack of authentic pure vomitoxin.
Simplex: A Method for Spectral Deconvolution Applicable to Energy Dispersion Analysis
Authors: Lam C. F. , Forst Art , Bank Harvey
Published: September 2005

In many types of spectral analysis, the quantitation of results is often complicated by the presence of overlapping peaks. We have treated deconvolution as a parameter estimation problem and have applied an optimization procedure called simplex to resolve the true area of overlapping peaks such as those frequently encountered in energy dispersion analysis spectra. This technique overcomes many of the limitations of present deconvolution techniques such as resolution enhancement and digital filter-correlation and has the added advantage of not involving the use of partial derivatives as encountered in gradient-type optimization techniques. This procedure has been applied to a series of artificially generated overlapping Gaussian peaks which are close analogs to actual peaks. The results of this study have shown that this function converges and the correct area of those overlapping peaks can be estimated by this deconvolution.
Spectroscopy of Transient Species and Molecular Ions in Matrices
Authors: Andrews Lester
Published: September 2005

Matrix-isolation spectroscopy is particularly useful for the study of transient species and molecular ions. New methods for producing and trapping reactive molecules for spectroscopic characterization are described. Matrix investigations of charge-transfer anionic species, free radicals, positive ions, and van der Waals molecules are discussed.
Versatile Mirror Mount for Stable Optical Instrumentation
Authors: Scheeline Alexander , Hosch Jimmy W. , Coleman David M. , Walters John P.
Published: September 2005

A mirror mount adjustable along three Cartesian axes and about two angular axes is described. The mount can support mirrors up to 8 in. (20.3 cm) in diameter, can be positionally set to high tolerances, and is stable over a period of years. Examples of mounting a variety of mirrors are given.
Inductively Coupled Plasma-Atomic Emission Spectroscopy: Prominent Lines
Authors: Winge R. K. , Peterson V. J. , Fassel V. A.
Published: September 2005

The prominent lines of 70 elements as emitted in an inductively coupled plasma excitation source have been identified. The lines are listed alphabetically by element and numerically by wavelength. Detection limit capabilities are estimated for each spectral line.
Trace Metal Analysis of Petroleum, Petroleum Products, and Alternative Fuels by Atomic Fluorescence/Emission Spectrometry
Authors: Brinkman D. W. , Whisman M. L. , Goetzinger J. W.
Published: September 2005

While atomic fluorescence is attractive as a sensitive multi-element technique, lack of a commercial instrument and the need for a dedicated computer system have discouraged its use. A system is described which incorporates atomic emission and fluorescence while using only commercially available instrumentation. A programable calculator operates the system and performs all data manipulation and reduction. The result is an instrument capable of doing routine multi-element analyses without the need for a highly trained operator.
Spectral Subtraction Using Fourier Transform Infrared Spectroscopy—Fact or Artifact
Authors: Strassburger John , Smith I. Trevor
Published: September 2005

Several operating and sample handling conditions were used to study their effect on spectral subtraction results using Fourier transform infrared spectroscopy. Purge rate, orientation of a heterogeneous sample and sample pathlength were varied to determine under what conditions and to what degree subtraction artifacts can be produced. To some degree, all of the conditions evaluated produced spectral subtraction artifacts although sample pathlength was found to have the greatest effect. Also under certain conditions, concentration differences taken from identical pathlength cells could not be totally nulled by subtraction manipulation.
Collection of Gas Chromatographic Fractions on Activated Charcoal and Identification by Infrared Spectroscopy
Authors: Goldfarb Daniella , Brown Chris W.
Published: September 2005

A novel method for collecting gas chromatographic fractions in commercially available tubes of activated charcoal has been developed and tested on a number of organic mixtures. The trapped fractions were desorbed with CS2 and infrared spectra of the CS2 solutions measured to provide positive identification of the eluents. The collection efficiency was found to be >68% in all but one case, and the resolution of the separation and collection method was adequate for making positive identifications. The advantages of using computerized subtraction of infrared spectra in identifying the eluents is also demonstrated.
Comparison of Experimental and ab Initio Line Strengths for H2O and HDO
Authors: Carney G. D.
Published: September 2005

An ab initio dipole moment function is used to predict line strengths for ν1, ν2, ν3, and 2ν2 bands of H2O and for the ν1 band of HDO. Except for lines in the ν1 band of H2O, ab initio and observed line intensities are in reasonable agreement.
13C Nuclear Magnetic Resonance Investigation of Ethylene Homopolymers, Copolymers and Model Systems. Chemical Shifts and Relaxation Times
Authors: Petrakis Leon , Seshadri K. S.
Published: September 2005

This is a report on the use of 13C NMR spectroscopy to study the structure of polyethylenes, polyethylene-olefin copolymers, and polyethylene model systems, through the observation of chemical shifts and spin-lattice relaxation times of individual carbons. Information is obtained on the type and numbers of side chains of polyethylenes from solution spectra at higher temperatures. The level of detectability of side chains is established at 2 side chain carbons per 1000 skeletal carbons. The observed chemical shifts are accounted for well by standard additivity schemes. The low-density polyethylenes show spectra which are distinctly different from high-density polyethylenes. The 13C-determined branch frequencies show the same general trend as the IR results, but it is also argued that the former are more accurate. Relaxation times of the various carbons of the model system C44 paraffin vary from 2.94 s for the backbone methylenes to 8.33 s for the terminal methyls to 11.11 s for α-methyls. Indicative of the behavior of olefin/polyethylene copolymers is the finding that all carbons of the copolymer have spin-lattice relaxation times of about 1.5 s, except for branch methyls which are 6 s. A series of polyethylenes at this high temperature shows relaxation times for the backbone methylene varying from 1.4 to 1.7 s, indicating that at this temperature, branching does not substantially affect the dynamic behavior of polyethylene.
Rapid Method for the Measurement of Monochromator Parameters in the near Infrared
Authors: Landa Isaac , Norris Karl H.
Published: September 2005

This paper describes a technique used for measuring monochromator characteristics in the near IR. It is shown that with an interferometer spectrophotometer, one can obtain parameters such as stray light, efficiency, resolution, bandwidth, and accuracy of wavelength readout. The advantage of this technique is simplicity and speed in data gathering.
Theory of High Frequency Differential Interferometry: Application to the Measurement of Infrared Circular and Linear Dichroism via Fourier Transform Spectroscopy
Authors: Nafie Laurence A. , Diem Max
Published: September 2005

A general method for the direct measurement of differential absorption intensities using a Fourier transform infrared spectrometer is described. The differential intensities must be higher in frequency than the interferogram frequencies and may arise from a periodic variation of the absorption strength of the sample, or by dichroic response of the sample to alternate states of polarization of the infrared beam. Specific expressions are presented for the measurement of circular and linear dichroism. These expressions represent an extension of the Grosjean-Legrand polarization modulation technique to Fourier transform interferometry.
Reflection-Absorption Infrared Spectroscopy and Ellipsometry of Epoxy Films on Metals
Authors: Boerio F. J. , Chen S. L.
Published: September 2005

Reflection-absorption infrared spectroscopy and ellipsometry have been used to determine the structure of films formed by an epoxy resin adsorbed from solution onto polished iron and copper mirrors. Films only about 15 Å thick were obtained. The infrared spectra of these films were characterized by absorption bands near 1500 and 1240 cm−1. Consideration of the thickness of the adsorbed films as well as wetability, surface coverage, and the relative intensities of the bands near 1500 and 1240 cm−1 indicates that the epoxy resin molecules are probably adsorbed with a vertical conformation where only a single oxirane oxygen atom is in contact with the surface.
Investigation of Bipolar Oscillatory Spark Discharges
Authors: Scheeline Alexander , Walters John P.
Published: September 2005

Bipolar spark discharges were investigated to determine whether the two cathodic vapor plumes successively created would mix, and, if so, whether energy transfer between the plume species would occur. Vapor mixing was observed; changes in sampling or excitation mechanisms were also indicated. Possible reasons for the changes in emission patterns are discussed.
Identification of a Charging Mechanism Using Infrared Spectroscopy
Authors: Fitzhenry B.
Published: September 2005

The working medium in an electrophoretic image display (EPID) is a colloidal dispersion of charged organic pigment particles in a dyed organic medium. This suspension is sandwiched between two transparent electrodes. The display utilizes the movement of these charged particles in an electric field. Displacement of the negatively charged particles toward the front electrode allows the viewer to see the color of the particles, whereas the dyed medium is seen when the particles are moved to the rear electrode. The particles are charged through the addition of an organic dispersant, which serves the additional function of providing steric stabilization for the particles. Creating a stable charge on the pigment particles is essential to the operation of the display. With the use of infrared spectroscopy, the mechanism through which the dispersant reacts with surface of the pigment particles to generate a charge was identified. One of the charged species resulting from an acid/base type interaction between pigment and dispersant was identified with a Perkin-Elmer infrared spectrophotometer. Simpler models of both the acidic pigment and the basic dispersant were also reacted in the same manner in the same solvent system and analyzed using infrared spectroscopy. Results from the model systems support the analysis of the data on the more complicated pigment/dispersant system.
Analysis of Low Alloy Steel Using Electrical Dispersed Samples
Authors: Eljuri E. , Lunar J. , Ghiglione M.
Published: September 2005

Chromium, nickel, copper, and manganese content was determined in samples of low alloy steel, B.S.S. certification, by means of a method described previously involving the dispersion of the sample by a condensed spark under water. Our main interest was to test the applicability for the atomic absorption analysis of the alloys. In nearly every case, the analysis was completed in less than 10 min. Other elements in the sample can be analyzed in a similar manner. Results on tungsten samples are also included.
Time-Lapse Infrared Spectroscopy
Authors: Hartshorn Jack H.
Published: September 2005

A new technique has been developed for assessing the chemical processes which take place during the formation of polymer coatings. It is capable not only of determining the reactions which take place but also when they happen. By programming the computer of a Fourier transform (or a computer controlled dispersive) infrared spectrometer to take and store spectra at frequent regular intervals, the progress of film formation can be followed in a manner similar to time-lapse photography. The computer can then be used to subtract one spectrum from another to show only the infrared band-shifts resulting from these reactions. By subsequently subtracting each spectrum from the previous one the sequence of reactions can be determined. The curing in air of a common oil-modified alkyd will be used to demonstrate this technique.
A New Approach to Spatially Resolved Flame Temperature Measurements
Authors: Fernandez Manahen A. , Bastiaans Glenn J.
Published: September 2005

Spatially resolved flame temperatures are spectroscopically measured using the slope method, over small (≃0.7 μl), relatively homogenous volumes of flame gases. The spatial resolution is uniquely obtained by introducing Co as a thermometric species into isolated volumes via the use of a droplet injection technique. By this method the emission of light is restricted to a limited volume, whose position in the flame can be accurately determined and controlled. Vertical resolution is determined by the width of the entrance slit of the monochromator employed (100 μm in this study), and horizontal resolution is limited by the width of the emission cloud formed by the injected droplets (1 to 3 mm). The possibility of self-absorption effects are greatly reduced because of the short radiation path length involved. The performance of the method is illustrated by its application to the spatial temperature mapping of the secondary reaction zone of a cylindrical air-acetylene flame. The effects of N2 as a sheathing gas and flame stoichiometry on the radial and vertical temperature distribution of the flame are also investigated. It is determined that a large, virtually isothermal, central zone exists in the flame.
Wavelength Calibration of Flat-Crystal and Convex Curved-Crystal X-Ray Spectrographs
Authors: Criss J. W.
Published: September 2005

Fixed-crystal spectrographs must be calibrated in terms of wavelength vs position on the film or detector array. This can be done either from the measured positions of lines with known wavelengths or from the geometrical design of the instrument. It is more accurate, however, to combine both kinds of information in a least-squares fitting method. This paper presents techniques for several spectrograph geometries, including flat and convex-curved crystals in reflection mode, with both flat and cylindrical film. Also treated is a less common case where the diffracting planes are inclined to the crystal surface. Uses of the calibration equations in wavelength determinations, resolution studies, and intensity measurements are discussed.
Theoretical Fitting of Computer Processed Laser Raman Spectra from Methane- and Propane-Air Flames
Authors: Stephenson David A. , Blint Richard J.
Published: September 2005

A technique for rapid acquisition and computer processing of Raman signals is described for probing premixed laminar hydrocarbon-air flames using laser Raman spectroscopy. Temperatures can be determined to within ±50°K by fitting the observed N2 spectrum at any point in the flame. Fits to the spectra of O2, CO, H2, and CO2 are used to measure their mole fractions at the calculated N2 temperature. For the remaining polyatomic species, the total area under the peak is the primary measure of their concentration.
The Determination of Chromium in a Nickel Base Cr-B-Si-Fe Alloy System by X-Ray Fluorescence
Authors: Brachfeld B. , Cambria F. , Palumbo M.
Published: September 2005

A method is described for the determination of chromium in a nickel base B-Cr-Fe-Si alloy powder. The existing technique began with the melting of as received powder samples in an electric button furnace, and analysis of the solid sample by x-ray fluorescence. The procedure gave erratic quantitative results for high chromium alloys because of the segregation associated with the precipitation of chromium borides. Dilution of the as received powders with 30% nickel before melting solved the problem of chrome boride segregation, as evidenced by the concurrence of results obtained by both x-ray fluorescence and wet chemical results for chromium percentage in the alloys.
An Application of Infrared Lasers to the Selective Detection of Trace Organic Gases
Authors: Sweger Daniel M. , Travis John C.
Published: September 2005

For molecules possessing a permanent electric dipole moment the Stark effect may be used to perturb the molecular energy levels and to “tune” some absorption lines into coincidence with fixed frequency lasers. The same perturbation may also be used to modulate the absorption and allow the use of sensitive ac detection techniques. In this paper we report quantitative results for four organic gases of industrial importance: vinyl chloride, vinylidene chloride, acrylonitrile, and methanol. All have overlapping absorption bands in the CO2 laser region. Because of the modulation techniques used, the observed signal as a function of electric field is the first derivative of the absorption line profile, and the peak-to-peak intensity of the derivative is the measured analytical signal. The analytical curve is a straight line over several orders of magnitude in concentration. In all cases, parts per million or sub-parts per million concentrations of the gases in air and/or nitrogen have been measured using a CO2 laser. The paper will include a discussion of interferences and selectivity of the technique.
Retardation of Surface Adsorption of Trace Metals by Competitive Complexation
Authors: Hoyle William C. , Atkinson Annette
Published: September 2005

The storage of samples containing trace metals has resulted in the adsorption of certain metals onto the surface of the container. The effect of the adsorption of trace amounts of lead and cadmium on subsequent analyses using atomic absorption spectroscopy was studied. The effects on adsorption by factors such as pH, container composition, buffer composition, metal concentration, and storage time were studied. Significant adsorption of trace amounts of lead and cadmium occurred rapidly onto both Pyrex and polyethylene containers in alkaline solution. Minimization of this adsorptive interference was attempted through the use of organic chelating agents. EDTA and thenoyltrifluoroacetone were utilized to provide retardation of the adsorption via a competitive complexation for the metal ion with the container surface. The presence of thenoyltrifluoroacetone and EDTA, in the otherwise identical solutions, successfully prevented the adsorption onto the surface of the container over a wide range of pH. In addition, the EDTA was also capable of rapidly desorbing lead which had been adsorbed for as long as 40 days on Pyrex and polyethylene surfaces.
The Vibrational Spectra and Structure of Crystalline Oxanilide
Authors: Tripathi G. N. R. , Katon J. E.
Published: September 2005

Laser Raman and infrared spectra of crystalline oxanilide have been investigated in the region 4000 to 40 cm−1. Spectral features support a trans configuration for the molecule. Vibrational coupling between the two phenyl groups is observed to be negligible. The fundamental frequencies identified in the spectra are tentatively assigned to approximate amide and phenyl modes.
Nondestructive NIR and NIT Determination of Protein, Fat, and Water in Plastic-Wrapped, Homogenized Meat
Authors: Isaksson Tomas , Miller Charles E. , Næs Tormod
Published: September 2005

In this work, the abilities of near-infrared diffuse reflectance (NIR) and transmittance (NIT) spectroscopy to noninvasively determine the protein, fat, and water contents of plastic-wrapped homogenized meat are evaluated. One hundred homogenized beef samples, ranging from 1 to 23% fat, wrapped in polyamide/polyethylene laminates, were used. Results of multivariate calibration and prediction for protein, fat, and water contents are presented. The optimal test set prediction errors (root mean square error of prediction, RMSEP), obtained with the use of the principal component regression method with NIR data, were 0.45, 0.29 and 0.50 weight % for protein, fat, and water, respectively, for plastic-wrapped meat (compared to 0.40, 0.28 and 0.45 wt % for unwrapped meat). The optimal prediction errors for the NIT method were 0.31, 0.52 and 0.42 wt % for protein, fat, and water, respectively, for plastic-wrapped meat samples (compared to 0.27, 0.38, and 0.37 wt % for unwrapped meat). We can conclude that the addition of the laminate only slightly reduced the abilities of the NIR and NIT method to predict protein, fat, and water contents in homogenized meat.
Infrared Photoacoustic Spectra of Gaseous Pentacarbonyl(Methyl)Manganese(I) and Pentacarbonyl(Methyl)Rhenium(I)
Authors: Butler Ian S. , Gilson Denis F. R. , Lafleur Dominique
Published: September 2005

Gas-phase IR photoacoustic (PA) spectra have been obtained for the volatile, solid pentacarbonyl(methyl)metal(I) complexes, CH3Mn(CO)5 and CH3Re(CO)5. The gaseous samples were apparently produced directly in the PA sample cup as the result of local surface heating effects. Vibrational assignments are given for the gas-phase spectra, especially for the binary v(CO) overtone and combinations which absorb in the near-IR region at ∼4000 cm−1. The data provide further support for near-IR/PA spectroscopy being a useful technique for the rapid, nondestructive identification of small amounts of organometallic carbonyl complexes.
Fiber-Optic Probe for Collection of Two-Photon Excited Fluorescence Spectra in Low-Temperature Glassy Solvents
Authors: Dinkel Debora M. , Lytle Fred E.
Published: September 2005

Low-repetition-rate pulsed lasers are excellent sources for two-photon excitation of samples frozen in low-temperature glassy solvents. Unfortunately, similar efforts to combine synchronously-pumped dye laser excitation with normal cryostats and sample cells have consistently failed. The continuous nature of the laser creates a weak refractive index gradient which causes the beam to wander randomly in space. We have found that a fiber-optic probe directly frozen in the glassy sample permits two-photon excited fluorescence spectra to be obtained. This arrangement is stable because the fiber restricts beam-induced refractive index changes to harmless expansion. Studies of fluxional fluorophores indicate that the viscosity at the fiber tip is not significantly changed under conditions of average power known to cause beam wander in ordinary cryostat cells.
Spectroscopic Effects of Organized Media on a Cyanine Dye/Phenanthrene Derivative
Authors: Green Michael D. , Patonay Gabor , Ndou Thilivhali , Warner Isiah M.
Published: September 2005

Absorbance and fluorescence characteristics of a cyanine dye/phenanthrene derivative are studied in the presence of β- and γ-cyclodextrin, Brij 35, cetyltrimethyl ammonium bromide (CTAB), and sodium dodecyl sulfate (SDS). The apparent association constant for the dye cyclodextrin complex is estimated with the use of Benesi-Hildebrand equations. Absorbance measurements are used to estimate the dimerization constant of the dye in aqueous solution.
Interaction of an Excimer-Laser Beam with Metals. Part III: The Effect of a Controlled Atmosphere in Laser-Ablated Plasma Emission
Authors: Lee Yong-Ill , Thiem Terry L. , Kim Gi-Ho , Teng Ye-Yung , Sneddon Joseph
Published: September 2005

The effects of pressure over the range 10 to 760 Torr and of atmosphere (air, argon, and helium) on an ArF-excimer laser ( λ = 193 nm) ablated plasma created above the surface of a copper target was studied with the use of emission measurements. These factors greatly influenced the shape, line-to-background (L/B) ratio, and temperature of the plasma. In general, the size of the plasma decreased with increasing pressure. In air or argon, and at pressures less than 50 Torr, the plasma consisted of two distinct regions. With the use of neutral copper [Cu(I)] lines, reduced pressure from 760 to 10 Torr resulted in a 7-fold increase in air and an 11-fold increase in an argon atmosphere. With the use of a helium atmosphere, the maximum line intensity was obtained at 50 Torr. This was a 1.5-fold increase over that obtained at 760 Torr. With a reduction in the pressure in air or argon, the position of maximum intensity (for copper atom and ion lines) moved away from the surface. For helium, the position of maximum intensity did not significantly vary in accordance with a reduction in the pressure. In general, the plasma temperature decreased with decreasing pressure.
Quantitative Analysis of Silica in Silica-Kaolin Mixtures by Photoacoustic and Diffuse Reflectance Spectroscopies
Authors: Pandurangi Raghoottama S. , Seehra Mohindar S.
Published: September 2005

The techniques of photoacoustic spectroscopy (PAS) and diffuse reflectance spectroscopy (DRS) are investigated for the quantification of silica using the IR bands at 1080,797,693, and 1875 cm−1. It is observed that, in both techniques, signal intensity increases linearly with mass initially. However, signal saturation sets in at much lower masses (>2 mg) in PAS than in DRS (>30 mg), showing that saturation is strongly technique dependent, in addition to having dependence on the absorptivity of the sample. These findings are applied to the quantification of silica in laboratory-generated silica-kaolin mixtures. It is shown that, with the use of the weaker band at 1875 cm−1 in DRS, satisfactory results for the quantification of silica are obtained.
Gated Integration of Transient Signals in 1/f Noise
Authors: Kale Uma , Voigtman Edward
Published: September 2005

The Mueller optical calculus is used to model common spectrometric experimental schemes. The effects of source and preamplifier noise on the precision of the measurement are investigated, and the effect of gate width variation for gated integration of Gaussian signal peaks in the presence of white or 1/ f type noise is evaluated. The results indicate that, for integration of a transient absorbance signal, the choice of gate width depends upon the type of noise, but not its source. For a transmittance (or emission) type of experiment, both the type and the source of the noise determine the gate width to be used for integration of the signal.
Surface Characterization of Gamma-Iron Oxides for Magnetic Memory Media Using Fourier Transform Infrared Photoacoustic Spectroscopy
Authors: Nishikawa Yuji , Kimura Ko , Matsuda Astuko , Kenpo Tsutomu
Published: September 2005

The interaction of gamma-iron oxide powder with several substances (silica, stearic acid, stearylamine, and polyurethane resin) was investigated with the use of Fourier transform infrared photoacoustic spectroscopy. The stearic acid was found to be chemisorbed onto the gammairon oxide surface through the carboxyl group and then dissociated the proton of the carboxyl group. It was also suggested that the stearylamine was chemisorbed onto the surface of the gamma-iron oxides through the NH2 group. In the case of polyurethane, a lower shift of the C=O stretching band and a decreasing of the relative absorption intensity of the NH deformation band were observed, indicating that a chemical interaction between the polyurethane resin and the oxides had occurred. The adsorption sites of these substances on the gamma-iron oxide were also considered.
Polycyclic Aromatic Nitrogen Heterocycles. Part IV: Effect of Solvent Polarity, Solvent Acidity, Nitromethane and 1,2,4-Trimethoxybenzene on the Fluorescence Emission Behavior of Select Monoaza- and Diazaarenes
Authors: Tucker Sheryl A. , Darmodjo Hardjanti , Acree William E. , Zander Maximilian , Meister Erich C. , Tanga Mary J. , Tokita Sumio
Published: September 2005

Fluorescence emission spectra are reported for naphth[2′l′8′7′: 4,10,5]anthra[l,9,8cdef]cinnoline, benzo[lmn][3,8]phenanthroline (also called 2,7-diazapyrene), benz[4,10]anthra[l,9,8cdef]cinnoline, naphtho[8,1,2hij]pyreno[9,10,ldef]phthalazine, acenaphtho[l,2b]pyridine, benzo[a]phenazine, indeno[l,2,3ij][2,7]naphthyridine, and indeno-[l,2,3ij]isoquinoline dissolved in organic nonelectrolyte solvents of varying polarity and acidity. Results of these measurements indicate that naphth[2′,1′,8′,7′:4,10,5]anthra[l,9,8cdef]cinnoline exhibits some signs of probe character as evidenced by changing emission intensity ratios; however, numerical values did not vary systematically with solvent polarity. The effect of nitromethane and 1,2,4-trimethoxybenzene as selective quenching agents on both the unprotonated and protonated PANHs was also examined. Nitromethane was found to quench fluorescence emission of roughly two-thirds of the alternant unprotonated PANHs studied to date. Emission intensities of the protonated PANHs remained essentially constant and were not affected by nitromethane. 1,2,4-Trimethoxybenzene, on the other hand, quenched the fluorescence emission of several unprotonated and all protonated PANHs examined.
Comparison of CARS Temperature Profile Measurements with Flow-Field Model Calculations in an MHD Diffuser
Authors: Singh Jagdish P. , Yueh F. Y. , Cook Robert L. , Lee J. J. , Lineberry J. T.
Published: September 2005

This paper reports on recent gas temperature profile measurements made on a large-scale coal-fired flow facility (CFFF) with a coherent anti-Stokes Raman spectroscopy (CARS) system. These measurements further demonstrate the application of advanced optical diagnostic methods to characterize large-scale processes. Data from the CARS gas temperature measurements taken in the CFFF diffuser during a recent long-duration experiment are discussed and analyzed. Details are given on the CARS system. Comparisons are drawn between the CARS data and flow-field modeling results. These results define the flow field and heat transfer in the diffuser and provide a basis for interpreting the CARS temperature measurements and further evaluating the flow-field model.
Performance of the New Single-Bore High-Pressure Pneumatic Nebulizer (SBHPPN) in Plasma Atomic Emission Spectrometry
Authors: Todolí José L. , Muñoz Maria , Valiente Manuel , Hernandis Vicente , Canals Antonio
Published: September 2005

The analytical performance of the new single-bore high-pressure pneumatic nebulizer (SBHPPN) has been evaluated in ICP-AES. It has been compared with a commercially available pneumatic all-glass concentric nebulizer. The new SBHPPN generates finer and narrower primary aerosols than the concentric nebulizer. With respect to the concentric nebulizer, the analyte transport rate for SBHPPN is 1.8 to 3.4 times higher, its sensitivity 2.8 to 3.8 times higher, and its limits of detection 2 to 5 times lower. The better performance shown by the SBHPPN has been verified in both the continuous and the discrete mode, as well as with high-salt-content solutions, showing no tendency to clog because of salt deposition.
Temperature Effect on Pyrene as a Polarity Probe for Supercritical Fluid and Liquid Solutions
Authors: Chen Shu-Hui , McGuffin Victoria L.
Published: September 2005

The effect of temperature on the fluorescence spectrum of pyrene in supercritical and liquid carbon dioxide and liquid organic solvents is systematically studied. The Py parameter (intensity ratio of vibronic bands 1 and 3) is found to increase with the density of supercritical carbon dioxide in the range from 0.54 to 0.75 g/cm3. This observation is consistent with the fact that dispersion forces, which represent the major interaction between pyrene and carbon dioxide, depend inversely on the sixth power of distance. However, the Py parameter of both supercritical and liquid carbon dioxide is also found to decrease with temperature at constant density, which is not consistent with expectations for dispersion forces. Carbon dioxide, which is generally regarded as a nonpolar solvent, shows a temperature effect comparable to that for polar liquid solvents. The origin of this temperature effect is examined in this study by computer simulation using both semiempirical molecular orbital and molecular mechanics methods. On the basis of these simulations, a strong electrostatic attraction arises between pyrene and carbon dioxide which is similar in magnitude to that with polar solvents. The temperature dependence of the Py parameter can be qualitatively explained by these simulation results.
Micron Surface-Enhanced Raman Spectroscopy of Intact Biological Organisms and Model Systems
Authors: Todd Elizabeth A. , Morris Michael D.
Published: September 2005

Surface-enhanced Raman spectra have been obtained within intact zebrafish embryos and inside the 500-fL pores of a Nucleopore filter membrane with the use of coated microelectrodes with 1–3 μm active silver tip diameters. The spectra obtained demonstrate the microelectrode's ability to penetrate biological membranes as well as restricted volumes.
Relationship between Detection Limits and Energy Quantities in Atomic Emission Spectrometry
Authors: Yngström Sten
Published: September 2005

A relationship involving detection limits of ionic lines in an inductively coupled plasma experiment is shown to derive from principles applied in determining atomic transition probabilities from intensity measurements in arc experiments. A new theory of spectral line intensity has been previously shown to be supported by the arc experiments and is now shown to be consistent with the results of the detection limit ICP experiment.
Characterization of Plasma-Modified Fluoropolymer Surfaces Using Steady-State and Time-Resolved Fluorescence Spectroscopy
Authors: Li Ming , Pacholski Michaeleen L. , Bright Frank V.
Published: September 2005

Poly(hexafluoropropylene-co-tetrafluoroethylene) (FEP) has been widely used in biotechnology because of its unique surface properties and biocompatibility. Recent work from our group has shown that plasma discharge-modified FEP can be used as the substratum for development of a very stable immunosensor. This result has prompted us to study further this new surface under ambient conditions. In this paper, we report on the covalent immobilization of a pyrene residue (-Py) onto FEP-APS (FEP-aminopropyl silane) surfaces and the characterization of FEP-APS-Py using steady-state and time-resolved fluorescence spectroscopy. Among the immobilization schemes tested, we found that the covalent coupling of pyrene-sulfonyl chloride to FEP-APS is the easiest and yields the most photostable FEP-APS-Py derivative. Steady-state emission spectra of FEP-APS-Py in contact with H2O, β-cyclodextrin (β-CD), and sodium dodecylsulfate (SDS) aqueous solutions differ considerably from those of Py-SO3 in solution. Time-resolved fluorescence spectroscopy of FEP-APS-Py demonstrates that the decay kinetics are strongly affected by the presence of ionic quenchers and molecular oxygen, as well as β-CD and SDS. The results are consistent with the suggestion that the APS-Py moiety undergoes a slow time-dependent reconfiguration at the FEP/APS interface.
Controlled-Pore Glasses Embedded in Plastic Optical Fibers for Gastric pH Sensing Purposes
Authors: Baldini F. , Bracci S. , Cosi F. , Bechi P. , Pucciani F.
Published: September 2005

The present work is concerned with the development of an optical-fiber pH sensor for gastric monitoring. Bromophenol blue is used as a chromophore, which is immobilized on controlled-pore glasses (CPGs) by means of a silylation process. As far as the optoelectronic unit is concerned, light-emitting diodes as sources and an appropriate electronic circuit as detection system are utilized. Treated CPGs are fixed at the end of two plastic optical fibers (core diameter = 500 μm) by means of a proprietary process; a reflector made of Teflon®, anchored to the distal end of the fibers, ensures good fibers/probe coupling efficiency. The behavior of the realized probe is carefully investigated, with particular attention devoted to the presence of hysteresis, to ionic strength and temperature effect, and to its lifetime. The fast response time, thanks to the absence of a mechanical envelope, the small dimensions of the probe, and the biocompatibility of the utilized materials make this sensor suitable for in vivo measurements.
Photophysics of 2-(4′-Dialkylaminophenyl)Benzothialzoles: Their Application for Near-UV Laser Dyes
Authors: Chou Pi-Tai , Martinez Marty L. , Cooper William C. , Chang Chen Pin
Published: September 2005

The photophysical properties and the first observation of UV laser generation of molecules based on 2-phenylbenzothiazole with electron-donating substituents at the 2′ and 4′ positions are reported. The high gain of the amplified spontaneous emission, good efficient laser output, and extreme photostability for this class of laser dyes make their practical application feasible when pumped by the third harmonic (355 nm) of the YAG laser.
Determination of Kinetic Parameters for the Dehydration of Calcium Oxalate Monohydrate by Diffuse Reflectance FT-IR Spectroscopy
Authors: Christy Alfred A. , Nodland Egil , Burnham Alan K. , Kvalheim Olav M. , Dahl Birger
Published: September 2005

Variable-temperature diffuse reflectance infrared spectroscopy was used to study the reaction kinetics of the dehydration of calcium oxalate monohydrate. The kinetic analysis of the dehydration process indicates that there are two reactions taking place, as well as the presence of two different equimole water molecular environments in the crystal structure of calcium oxalate monohydrate. Partial least-squares calibration of the dehydration profiles was carried out to identify the evolution sequence of the two different types of water molecules in the crystal structure of calcium oxalate monohydrate. The results indicate that the water molecules in the crystal structure which are responsible for the stretching absorptions at 3428 and 3336 cm−1 are eliminated first at a higher rate, during the first part of the reaction, and the others responsible for the absorptions at 3486 and 3058 cm−1 are eliminated at a later stage. The unexpected and unidentified band arising from bending modes of one of the types of water molecules is shown to arise from the same water molecules that are responsible for the stretching absorptions at 3486 and 3058 cm−1. Kinetic parameters were determined for the dehydration step, and the overall activation energy calculated for the dehydration step is in agreement with values reported in the literature. However, the clear presence of two distinct reactions invalidates all previous determinations of reaction order.
Fluorescence Characterization of the Cyclodextrin/Pyrene Complex Interaction with Chiral Alcohols and Diols
Authors: Schuette Jodi M. , Will A. Yvette , Agbaria Rezik A. , Warner Isiah M.
Published: September 2005

The chiral properties of cyclodextrins (CDs) facilitate the formation of diastereomeric complexes with a number of pesticides and pharmaceuticals which are also frequently composed of one or more chiral centers. The roles of chirality and structural volume in CD binding to a homologous series of linear, chiral alcohols and diols are evaluated by comparing the trend in the pyrene fluorescence I/III band ratio and the hydrophobicity for the CD/pyrene complex with CD/pyrene complexes incorporating achiral alcohols. Stronger hydrophobicity is observed for complexes capped by chiral alcohols relative to complexes formed with a similar achiral counterpart, suggesting the importance of the alcohol chiral center. Furthermore, the diols induce a more hydrophobic environment than their alcohol counterparts with the β-CD/pyrene complex, while the converse is the case for the γ-CD systems. The systems involving γ-CD were also compared by use of pyrene fluorescence lifetime measurements.
Immunohistochemical Analysis of MUC5B Apomucin Expression in Breast Cancer and Non-malignant Breast Tissues
Authors: Sóñora Cecilia , Mazal Daniel , Berois Nora , Buisine Marie-Pierre , Ubillos Luis , Varangot Mario , Barrios Enrique , Carzoglio Julio , Aubert Jean-Pierre , Osinaga Eduardo
Published: September 2005

A deregulation of several MUC genes (MUC1, MUC2, MUC3, MUC5AC, and MUC6) was previously demonstrated in breast carcinomas. Considering that recently we found the “non-mammary” MUC5B mRNA in primary breast tumors ( Berois et al. 2003 ), we undertook the present study to evaluate the expression profile of MUC5B protein product in breast tissues, using LUM5B-2 antisera raised against sequences within the non-glycosylated regions of this apomucin. Expression of MUC5B by breast cancer cells was confirmed by immunocytochemistry, in situ hybridization, and Western blot on MCF-7 cancer cells. Using an immunohistochemical procedure, MUC5B apomucin was detected in 34/42 (81%) primary breast tumors, in 13/14 (92.8%) samples of non-malignant breast diseases, in 8/19 (42.1%) samples of normal-appearing breast epithelia adjacent to cancer, and in 0/5 normal control breast samples. The staining pattern of MUC5B was very different when comparing breast cancer cells (cytoplasmic) and non-malignant breast cells (predominantly apical and in the secretory material). We analyzed MUC5B mRNA expression using RT-PCR in bone marrow aspirates from 22/42 patients with breast cancer to compare with MUC5B protein expression in the primary tumors. Good correlation was observed because the six MUC5B-positive bone marrow samples also displayed MUC5B expression in the tumor. Our results show, for the first time at the protein level, that MUC5B apomucin is upregulated in breast cancer. Its characterization could provide new insights about the glycobiology of breast cancer cells.