bluuebunny/crossref_metadata_2025 huggingface dataset:
New Dilution Materials for Sensitivity Enhancement in the FT-IR Spectroscopy of Pitches as Typical Highly Scattering Samples
Authors: Kaihara Mikio , Mametsuka Hiroaki , Gunji Naoki , Iwata Hideo , Gohshi Yohichi
Published: June 2005

Because they are composed of a variety of chemical components, pitches are possessed of highly scattering properties. Therefore, the spectra of pitches obtained by FT-IR have large backgrounds, and the backgrounds have a detrimental influence on the accuracy of analysis. Recently, the diffuse reflection method has been widely used for analyzing pitches, although it has been pointed out that the method has some problems; for example, diffuse reflection cannot obtain very sharp absorption peaks. In this paper, new dilution materials are developed and proposed that allow one to obtain fine spectra of pitches. With the use of our dilution materials, the shapes of absorption peaks become more sharp, the intensities of the peaks increase considerably, and the backgrounds of those spectra are reduced to a large extent. The quality of the spectra of the pitches is considerably improved. Our method may prove to be a solution for dealing with the problem posed by backgrounds, which have heretofore seriously affected accuracy in the analysis of spectra.
Micro-Raman Spectroscopy of Selected Solid UxOyFz Compounds
Authors: Armstrong D. P. , Jarabek R. J. , Fletcher W. H.
Published: June 2005

Micro-Raman spectroscopy has been utilized to examine the spectra of solid samples of α-UF5, β-UF5, UF6, three types of UO2F2, the powder residue from a static UF6 release, and γ-UO3. The spectra are presented and compared to previous literature values, with new features indicated where appropriate. With the implied constraint of proper sample handling, micro-Raman spectroscopy is a useful technique for the ready identification of uranium fluorides, oxyfluorides, and oxides.
Anomalous Dispersion Effects in Diffuse Reflectance Infrared Fourier Transform Spectroscopy: A Study of Optical Geometries
Authors: Hembree D. M. , Smyrl H. R.
Published: June 2005

In this report, the two most common diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) optical geometries (on-axis and off-axis) are investigated in terms of adherence to the Kubelka-Munk theory. It was found that specular reflection, whether in the form of regular Fresnel reflection or diffuse Fresnel reflection, is the major cause of spectral distortion in typical diffuse reflectance measurements. A discussion of the origin of the variation in specular background associated with resonances is presented. Once the adverse effects of specular reflection are minimized, the linear relationship between response and concentration predicted by Kubelka-Munk theory was found to extend to concentrated samples. Up to a point, this was the case even for intense absorption bands where anomalous dispersion leads to large changes in specular intensity.
Exciplex Fluorescence Thermometry of Liquid Fuel
Authors: Stufflebeam John H.
Published: June 2005

An experimental program is described that investigates the application of exciplex fluorescence to the internal thermometry of flowing liquid decane in the temperature range 24–91°C. Decane is doped with pyrene and excited by laser radiation at 354.7 nm. A library of temperature-dependent, exciplex fluorescence spectra is obtained from a static, isothermal solution, and the spectral features are analyzed to produce a temperature-prediction algorithm. The solution then flows through a temperature gradient region, and the laser-induced fluorescence spectra that are recorded are used to determine the local temperature in the solution by application of the algorithm. Excellent agreement between the predicted temperatures and those measured by thermocouples in contact with the solution is realized. The experiment demonstrates the high accuracy and spatial resolution obtainable with this laser-based thermometry technique.
Efficiency in Circular Polarization Modulation
Authors: Korte Ernst-Heiner , Jordanov Bojidar
Published: June 2005

The efficiency of a retarder for conversion of linear polarization into circular polarization is defined. The average efficiency is calculated for the cases in which either the polarization plane of incident radiation or the phase retardation is modulated. Three different modulation functions are considered.
Laser-Based Photoacoustic Densitometer for Two-Dimensional Scanning of Thin-Layer Chromatographic Plates
Authors: Kawazumi Hirofumi , Yeung Edward S.
Published: June 2005

Laser-based photoacoustic densitometry was applied to two-dimensional analysis in thin-layer chromatography. An acousto-optic device was used to provide both intensity modulation and a rastering scan. The spatial resolution is 25 × 60 spots for an area of 25 × 50 mm on the thin-layer chromatographic plate. Three detection modes, normal modulation, resonant modulation, and unmodulated rapid scan modes were compared. Detection limits in the most sensitive mode and in the fastest mode are 350 pg with scan time of 153 s and 6.9 ng with scan time of 1.5 s, respectively.
Examinations of the Matrix Isolation Infrared Spectra of Organic Compounds: PART XIII
Authors: Coleman W. M. , Gordon Bert M.
Published: June 2005

Matrix isolation Fourier transform infrared (MI/FT-IR) spectra have been collected on a series of internal alkenes, a series of hydroxy-substituted ketones, and a series of hydroxy-substituted esters. Assignments of double bond position and geometry are possible in the alkenes, due to the resolution of absorption bands of very similar energies. The location of the absorption bands for the alkenes was found to be very similar to the values found for the vapor-phase and condensed-phase spectra. Multiple carbonyl absorptions have been found in the MI/FT-IR spectra of the hydroxy ketones and hydroxy esters. Trends in the multiplicity of the carbonyl absorption patterns for these compounds as a function of ring size and hydroxyl carbon substitution have been used to document the presence of extensive intramolecular hydrogen bonding. The argon matrix as a phase for the study of stable organic compounds has, again, with this information, been shown to be unique.
Single-Photon-Decay Spectroscopy by Means of a Laplace Transform Method: Application to a Crystal of TMMC
Authors: González F. , López R. J. , Moreno F.
Published: June 2005

In order to demonstrate the applicaton of a Laplace transform method to a real experiment of single-photon-decay spectroscopy, we have measured the lifetime of the 4 T1 state of Mn2+ in an undoped TMMC crystal at room temperature. The theoretical predictions for exponentially decaying signals have been reported in a previous work by means of a computer simulation of the experiment. The experimental results obtained in this work by means of the Laplace transform method show its goodness for obtaining lifetimes of long-lived levels at low fluorescence intensities (less than one photon per lifetime). Other integration methods are presented for improving the signal-to-noise ratio of the detected signal.
Laser Spectroscopic Studies of a Helium Flowing Afterglow
Authors: Fleitz P. A. , Seliskar C. J.
Published: June 2005

The reaction zone of a helium flowing afterglow has been characterized as consisting of nearly thermalized 23 S metastables in a bath of ground-state helium atoms. LIF studies show that collision-induced angular momentum scrambling occurs efficiently among the n = 3 states of helium, even to the extent of including a small amount of intersystem crossing. LOG transients have been characterized for the afterglow reaction zone, and it is proposed that these signals are associated with a pressure pulse generated by laser pumping the helium 23 S metatables.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XII
Authors: Coleman W. M. , Gordon Bert M. , Lawrence Brian M.
Published: June 2005

Matrix isolation Fourier transform infrared spectra (MI/FT-IR), mass spectra (MS), carbon-13 Nuclear Magnetic Resonance (13C-NMR) spectra, condensed-phase infrared spectra, and vapor-phase infrared (IR) spectra are presented for a series of terpene compounds. Subtle differences in positional and configurational isomers commonly found with terpenes could be easily detected by the MI/FT-IR spectra. The results are comparable in some aspects to those obtainable from 13C-NMR and thin-film IR; however, most importantly, they are acquired at the low nanogram level for MI/FT-IR, as compared to the milligram level for the other techniques. These results represent an advance in the technology available for the analysis of complex mixtures such as essential oils containing terpene-like molecules.
Acoustic Levitation as an IR Spectroscopy Sampling Technique
Authors: Cronin J. T. , Brill T. B.
Published: June 2005

Acoustic levitation of liquid droplets (< 4 mm diameter), bubbles, and solid particles is described as an unusual sampling technique for obtaining the infrared spectrum of samples that might be incompatible with conventional sample support methods, and for studies of materials under extreme conditions. Excellent FT-IR spectra were recorded of bubbles of a concentrated aqueous nitrate solution, of mineral oil, and of an aqueous surfactant solution. Polymethacrylic acid packing foam also produced a high-quality spectrum. Large aqueous droplets and dense solids gave unsatisfactory spectra. The design of the levitator and various spectroscopic considerations are discussed.
Real-Time Particle Size Measurements in Laser-Generated Plumes by Mie Scattering
Authors: Kimbrell Sandra M. , Yeung Edward S.
Published: June 2005

We report the application of a light scattering technique for the determination of particle sizes in a laser-generated plume. This procedure is based on the dissymmetry ratio obtained for observation at different angles relative to the excitation source. Good spatial and temporal resolution is achieved. The plume can be probed repeatedly during its lifetime. Large carbon particles, on the order of 85 nm and larger, are observed in a plume generated from pyrolytic carbon.
Polycyclic Aromatic Hydrocarbon Solute Probes. Part V: Fluorescence Spectra of Pyrene, Ovalene, Coronene, and Benzo[ghi]perylene Dissolved in Liquid Alkylammonium Thiocyanate Organic Salts
Authors: Street Kenneth W. , Acree William E. , Fetzer John C. , Shetty Prabhakara H. , Poole Colin F.
Published: June 2005

Fluorescence properties of pyrene (Py), benzo[ghi]perylene (BPe), coronene (Co), and ovalene (Ov) dissolved in n-butylammonium thiocyanate, sec-butylammonium thiocyanate, and dipropylammonium thiocyanate are reported. Solvent polarities of the thiocyanate salts are estimated from the fluorescence emission intensity ratios of bands I and III (i.e., Py = I/III) of the polycyclic aromatic hydrocarbon vibronic spectra. Calculated BPe, Co, and Ov values indicate that all three thiocyanate salts are comparable in polarity to cyclohexanone.
NMR Imaging of Solvent Diffusion in Polymers
Authors: Weisenberger L. A. , Koenig J. L.
Published: June 2005

Nuclear magnetic resonance (NMR) imaging is sensitive to the mobile protons of solvent molecules and, as such, is well suited for studying the solvent diffusion in polymers. The fundamentals of NMR imaging are described, providing a platform for application of NMR imaging to diffusion processes in polymers. The constraints on the imaging experiment imposed by the diffusion process are discussed with respect to sample geometry and the rate of diffusion. A fast imaging scheme known as FLASH is described as an alternative method which reduces the influence of the diffusion rate and NMR relaxation parameters. Example images are given with regard to each of the constraints. An example of the successful application of NMR imaging to the study of Case II diffusion in PMMA is also given. The advantages and disadvantages of NMR imaging as applied to diffusion in polymers, as well as examples of the diffusion process that NMR imaging is uniquely qualified to study, are given in the conclusion.
Simultaneous Detection of Optical Isomers and the Separation of Overlapping Resonances in a 1H NMR Spectrum of (+/-)-2,2-Dimethyl-1-Phenyl-1-Propanol Using an NMR Shift Reagent
Authors: Cholli Ashok L. , Lau Miu-Ling
Published: June 2005

The enantiomer separation and the spectral simplification of overlapped resonances in a high-resolution 1H NMR spectrum of a model compound have been successfully accomplished with the use of paramagnetic shift reagent. Both 1H and 13C NMR have been applied to determine the composition of a mixture containing optically active enantiomers of (+/-)-2,2-dimethyl-1-phenyl-1-propanol.
Semiquantitative Survey Capabilities of Inductively Coupled Plasma Mass Spectrometry
Authors: Ekimoff David , Van Norstrand Ann Marie , Mowers David A.
Published: June 2005

The capabilities of Inductively Coupled Plasma Mass Spectrometry for elemental survey analysis have been characterized. The analysis is a three-step process which involves collecting a spectrum from mass 5 to 240, deconvolving the spectrum into elemental constituents, and converting the elemental count rates to concentrations. The entire process takes less than 10 min per sample. Detection limits are generally less than 1 ng/mL, and the precision of 16 replicate analyses of a sample is between 5 and 20% for the majority of the elements detected. It was determined that the figures of merit for this analysis did not vary significantly as the matrix changed.
Laser-Enhanced Ionization in Microwave-Induced Plasmas
Authors: Lysakowski Richard S. , Dessy Raymond E. , Long Gary L.
Published: June 2005

Laser-Enhanced Ionization (LEI) signals have been detected for Na, Li, and Ba analytes in a microwave-induced plasma (MIP). A 300-mW continuous-wave (cw) dye laser pumped by a 5-W argon-ion laser was used to promote measurably increased ionization rates for these elements. A low-power, high-efficiency microwave plasma at 1 atmosphere with nitrogen and nitrogen-containing support gas was employed as the atom reservoir. The effects of varying applied microwave power, support gas composition, electrode voltage, and geometry were studied and results are given. The experimental variables that most significantly affect LEI signal intensity are: (1) electrode geometry, spacing, voltage, and distance above the cavity; (2) applied microwave power; (3) gas composition in an argon and nitrogen mixture; and (4) laser intensity. Experimental results are presented from the studies of Na LEI signals as a function of each one of these variables. Preliminary analytical studies yield Na detection limits in the low ng/mL range, showing this method to be competitive with other laser-based ionization methods.
Matrix-Isolated Surface-Enhanced Raman Spectroscopy (SERS): The Role of the Supporting Matrix
Authors: Soper Steven A. , Kuwana Theodore
Published: June 2005

The influence of a supporting matrix in surface-enhanced Raman spectroscopy (SERS) has been investigated. The support matrices were conventional TLC plates onto which Ag colloidal hydrosols mixed with the dye pararosaniline had been deposited. The protocol of preparation of the Ag sol as well as the type of TLC plate had a profound effect upon the intensity of the SERS signals of pararosaniline. The Ag sol and the TLC plate that resulted in the maximum SERS intensities yielded a detection limit of ∼ 108 femtomols (33 pg) of dye deposited onto the TLC plate. Deposition of the dye/sol mixture onto the supporting matrix also resulted in stable SERS signals for extended periods of time, in contrast to the solution-phase case, where the signal is only transient in nature. In order to obtain the SERS spectra, a remote sensing Raman spectrometer was constructed and is described.
A New Mathematical Procedure for NIR Analysis: The Lattice Technique. Application to the Prediction of Sugar Content of Apples
Authors: Robert P. , Bertrand D. , Crochon M. , Sabino J.
Published: June 2005

Analytical applications of near-infrared spectroscopy require the determination of calibration equations linking chemical and spectral values. Such equations are difficult to update by including new calibration specimens. A new procedure for prediction which was not based on multiple linear regression has been investigated. This procedure could be included in a data base system. The proposed method consists of three steps: compression of the spectral data by applying principal component analysis, creation of a predictive lattice, and projection of the spectra of unknown specimens on to the predictive lattice. This enables the prediction of chemical data that are not perfectly linked to spectral data by a linear relationship. The procedure has been applied to the prediction of the refractive index of apples. A predictive lattice was designed with the use of 45 specimens of calibration. A prediction with 43 verification specimens gave a standard error of 0.8%, which appeared sufficient for grading apples in quality classes. Further studies are required in order to include the proposed method in spectral libraries specializing in analytical applications.
Simultaneous Detection of One-Dimensional Laser-Induced Fluorescence or Laser Light Scattering Images in Plasmas
Authors: Olesik John W. , Williamsen Eric J.
Published: June 2005

An instrumental system to simultaneously detect one-dimensional atomic or ionic fluorescence images is described. The instrument can also be used to acquire laser light scattering images or laterally resolved emission images. The fluorescence, scattering, or emission image passes through a monochromator and is re-imaged on an intensified diode array detector. Measurement of spatially resolved ground-state populations in inductively coupled plasmas is discussed. Interpretation of the fluorescence data obtained under different plasma operating conditions is considered. Results with the use of laser-induced fluorescence imaging to study the effect of sample transport rate, concomitant species-induced matrix effects, and modulated power plasmas are discussed. Comparison of fluorescence and emission images shows the complementary nature of the information provided by each. Laser light scattering off intact droplets or particles in a 1.0-kW inductively coupled plasma is discussed. Means to minimize the scattering signal are evaluated. Detection of laser light scattering images is discussed.
Diffuse Transmittance Spectroscopy of Polymeric Fibers
Authors: Taboudoucht A. , Ishida H.
Published: June 2005

In this work, a new Fourier transform infrared spectroscopic technique (diffuse transmittance) is introduced. Its principle is based on the collection and the analysis of the diffusely transmitted infrared radiation through fibrous samples. The qualitative as well as the quantitative aspects of the method have been investigated. A comparative analysis of diffuse reflectance (DRIFT) and diffuse transmittance (DT) spectra shows that orientation of the sample has little effect on DT spectra, as compared with DRIFT spectra. With the use of ultra-high modulus polyethylene fabrics as a substrate coated with 12-nitrododecanoic acid, the concentration dependence of F( T), a function of the diffuse transmittance T, defined as F( T) = (1 – T)2/2 T, was investigated within the coating thickness range of 0 to 50 nm.
Thin-Film Optical Constants Determined from Infrared Reflectance and Transmittance Measurements
Authors: Buffeteau Thierry , Desbat Bernard
Published: June 2005

A general method based upon reflectance and transmittance measurements in the infrared region has been developed for the determination of the optical constants n( v) and k( v) of thin films deposited on any substrate (transparent or not). The corresponding computer program, written in FORTRAN 77, involves three main parts: (1) a matrix formalism to compute reflection and transmission coefficients of multilayered systems; (2) an iterative Newton-Raphson method to estimate the optical constants by comparison of the calculated and experimental values; and (3) a fast Kramers-Krönig transform to improve the accuracy of calculating the refractive index. The first part of this program can be used independently to simulate reflection and transmission spectra of any multilayered system using various experimental conditions. Two practical examples are given for illustration. Simulation of reflection spectra at grazing incidence for thin films deposited on a metal surface and determination of the optical constants for thin CaF2 layers deposited on a silicon substrate are presented.
An Optical Sensor Based on Infrared Spectroscopy
Authors: Jones Thomas P. , Porter Marc D.
Published: June 2005

A thin-film pH sensor based on vibrational spectroscopy has been developed. The sensor was constructed by the immobilization of Congo Red at a base-hydrolyzed cellulose acetate film that had been coated onto a ZnSe internal reflection element. The protonation of the azo groups of Congo Red was monitored as a function of pH with infrared internal reflection spectroscopy. The response characteristics of this sensor demonstrate the potential utility of applying infrared spectroscopy to detect the response of thin film sensors. Opportunities to design sensors based on the molecular specificity of infrared spectroscopy are briefly discussed.
Dual-Wavelength Photothermal Refraction Spectrometry for Small-Volume Samples
Authors: Tran Chieu D. , Xu Minren
Published: June 2005

A novel dual-wavelength photothermal refraction spectrometer that is capable of simultaneously measuring photothermal refraction at two different wavelengths has been developed. In this instrument, the two excitation wavelengths were provided by an argon-ion (488 nm) and a He-Ne (632.8 nm) laser. These two pump beams were sequentially modulated at the same frequency by means of two mechanical choppers. The photothermal refraction signals produced by the sample absorption of these two pump beams were monitored by a probe beam which was derived from the same He-Ne laser by a beamsplitter. Compared to the single-wavelength techniques, this dual-wavelength apparatus has advantages that include its ability to provide fingerprints and identification of the analyte (as the ratio of the two signals at the two different excitation wavelengths) and to simultaneously determine two-component samples. With this apparatus, the detection limit for two-component samples containing oxohydroxy bis-(8-hydroxy quinoline)-vanadium and 1,2-diamino-anthraquinone in methanol with the use of 25-mW excitation beams modulated at 3.4 Hz is estimated to be 10−7 M. This corresponds to the absorbance of 10−6 for a probe volume of 10−11 L.
Effects of the Anesthetic Dibucaine on the 31P NMR Spectra of Maize Root Tissue
Authors: Gerasimowicz W. V. , Kurantz M. J. , Pfeffer P. E. , Psorsas N. A.
Published: June 2005

We present the first in vivo31P NMR study describing the effect of the anesthetic dibucaine on the levels of phosphorus-containing metabolites (G-6-P, Pi, NTP, NADP, and UDPG) in maize root tissue which was maintained in an aerobic state through modern perfusion techniques. The effects of dibucaine are demonstrated as a function of Ca2+ concentration at several pH values. Our results indicate that dibucaine alters the 31P spectra and the membrane-lipid composition of the roots upon introduction into the perfusate medium. Ca2+ inhibits the effects of the dibucaine as monitored by suppression of the 31P spectral changes induced by the anesthetic alone. Desaturase enzymatic inhibition has also been shown to occur in the presence of the anesthetic (in the absence of Ca2+), resulting in increased relative saturation of the fatty acids comprising the root tissue, with a marked decrease in linoleate (18:2) balanced by proportional increases in the more saturated fatty acid species. These compositional changes have been evaluated with respect to the real-time metabolic results as observed throughout the 31P NMR spectral studies.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds. Part XIV: Evaluation of Library Search Routines for Identification of Essential Oil Components
Authors: Coleman W. M. , Gordon Bert M.
Published: June 2005

A set of five search routines—absolute difference, absolute derivative, square difference, square derivative, and Euclidean difference—have been applied to the analysis of the matrix isolation/Fourier transform-infrared spectra (MI/FT-IR) of the components of four essential oils: coriander oil, lemon oil, geranium oil, and citronella oil. The routines were tested under a variety of parameters on a diverse set of compounds and IR spectra. Areas of acceptable performance by the routines as well as areas of marginal performance are discussed. Under the conditions of this study, the absolute derivative routine is judged to be the most acceptable of the five.
Quantitative Analysis of Liquid Fuel Mixtures with the Use of Fourier Transform Near-IR Raman Spectroscopy
Authors: Seasholtz M. B. , Archibald D. D. , Lorber A. , Kowalski B. R.
Published: June 2005

Near-infrared Fourier transform (near-IR FT) Raman spectroscopy was used to predict mass percentages of liquid fuel mixtures without the use of an internal standard. The 29 mixtures making up the calibration set were composed of varying mass percentages of unleaded gasoline, superunleaded gasoline, and diesel. Predictions were made with the use of classical least-squares with the pure components. Root mean square error (RMSE) values for all samples were 13.5, 13.8, and 5.2% (absolute error) for unleaded, superunleaded, and diesel, respectively. Using an estimate of the pure spectra determined by calibration gave RMSE values of 13.3% for unleaded, 12.2% for superunleaded, and 5.0% for diesel. A partial least-squares (PLS) model was able to partially compensate for matrix effects. Using different portions of the Raman spectra reduced the RMSE to 5.7% for unleaded, 5.2% for superunleaded, and 1.3% for diesel.
Determination of Ionization Efficiencies of Excited Atoms in a Flame by Laser-Enhanced Ionization Spectrometry
Authors: Axner O. , Berglind T.
Published: June 2005

State-specific ionization efficiencies for excited Li and Na atoms in acetylene/air flames have been determined. The ionization efficiencies, i.e., the probability that the excited atoms ionize instead of returning to the ground state, are determined by relating collision-assisted Laser-Enhanced Ionization (LEI) signals from various excited states with laser-induced photoionization signals. The ionization efficiencies are found to decrease (from being one at the ionization limit) almost monotonically as the lower atoms are excited. The most striking feature, however, is that the decrease of the ionization efficiency values is generally found to be less than the decrease of the Boltzmann factor, exp(- δE/kT), when the energy difference, δE, between the excited state and the ionization limit is increased. The ionization efficiencies are found to be close to unity for states with δE < kT and approximately 50% for states with δE ≈ 2.5 kT ( np ≈ 6 p). For the lower states, the ionization efficiencies are found to be approximately five times larger than the Boltzmann factor.
Adsorption Density Calculations from in Situ FT-IR/IRS Data at Dilute Surfactant Concentrations
Authors: Kellar Jon J. , Cross W. M. , Miller J. D.
Published: June 2005

Adsorption densities of the surfactant oleate at the surface of a fluorite crystal have been calculated from in situ FT-IR internal reflection spectroscopic (1RS) data at very low surfactant concentrations. For the first time, a complete adsorption isotherm (5 × 10−7 to 5 × 10−4 M) has been calculated from the in situ spectral data with the use of internal reflection theory. It was found that monolayer coverage occurred at very low surfactant concentrations (<10−5 M), while at higher bulk concentrations, adsorption consists of multilayers of what appears to be surface-precipitated calcium dioleate. Calculated absorption densities by this in situ method agree quite well with those found previously by more traditional experimental techniques. These results provide considerable confidence that quantitative in situ FT-IR/IRS analysis of surfactant adsorption at the surface of reactive internal reflection elements is possible.
A New Liquid-Crystal-Based Fiber-Optic Temperature Sensor
Authors: Zhu Chu , Hieftje Gary M.
Published: June 2005

A new fiber-optic temperature sensor has been developed, based upon selective reflection from a cholesteric liquid crystal. The change of reflected-light intensity can be 40 times larger than background over a temperature range of only 0.4°C. For the demonstrated system, the temperature at which maximum reflection occurred was at 14.578°C, with a standard deviation of 0.026°C. The relative standard deviation of the peak reflected-light intensity was 7.1%. The dependence of the magnitude of reflection and that of peak temperature on the heating rate were studied. The response time of the present sensor is about 2 s, but it could be shortened with slight design modifications. Each sensor of the new type should be applicable to temperature sensing or control over a temperature range of about 1°C.
Gas Chromatography/Matrix Isolation-Infrared Spectrometry for the Identification of Polycyclic Aromatic Hydrocarbons in Urban Air Particulate Matter
Authors: Childers Jeffrey W. , Wilson Nancy K. , Barbour Ruth K.
Published: June 2005

The capabilities of gas chromatography/matrix isolation-infrared (GC/MI-IR) spectrometry for detecting and identifying polycyclic aromatic hydrocarbons (PAHs) in urban air particulate matter are demonstrated. The ability of GC/MI-IR to discriminate between PAH isomers that are difficult to distinguish by conventional electron-impact ionization gas chromatography/mass spectrometry is shown. The MI-IR spectra of PAHs obtained under GC/MI-IR conditions are comparable to those reported in the literature that were obtained by using slow-spray-on matrix deposition techniques.
Perturbation of Surface Species on Zeolite HY by Xe Observed by FT-IR Spectroscopy
Authors: Wang H. Paul , Garland Ben A. , Gerhard Achim , Liang Jim , Eyring Edward M.
Published: June 2005

The perturbation of surface species of zeolite HY by Xe has been studied with the use of in situ FT-IR spectroscopy. The Brönsted acid sites, characterized by a band at 3638 cm−1, are located in the zeolite supercages, as suggested previously, while Brönsted acid sites attributed to a 3545-cm−1 band are located in the small zeolite cages and are inaccessible to the Xe molecules. The Brönsted acid sites in the supercages are found to have a weaker acidity than those in the small cages. The data also indicate that pyridine molecules are more strongly bonded to the super-cage Brönsted acid sites than are the NH3 molecules. This work is an example of the usefulness of liquid-nitrogen-temperature FT-IR techniques, coupled with multiple-scan data acquisition methods, for studying weak interactions between Xe and zeolite surface species in detail. This work also shows how FT-IR spectroscopy can complement Xe-129 NMR spectroscopy in studies of the nature of zeolite surface species using Xe as a probe molecule.
Wavelength Calibration of Optical Multichannel Detectors in Combination with Single- and Double-Grating Monochromators
Authors: Lindrum Michael , Nickel Bernhard
Published: June 2005

For the measurement of a spectrum with an optical multichannel detector (OMCD), the relation N = N(λ) or λ = λ( N) between the channel number N and the wavelength λ must be known. For an ideal OMCD, N(λ) and λ( N) are completely defined by the physical parameters of the monochromator and the channel spacing of the OMCD. Series expansions N = N0 + Σ kA k(λ – λ0) k and λ = λ0 + Σ kBk( N – N0) k are given for single-grating monochromators ( k = 1, 2, 3) and double-grating monochromators ( k = 1, 2). The validity of the series expansions has been checked experimentally and numerically for a double monochromator.
Fermi Resonance Variability Induced by Solute/Solvent Interaction: Phthalic Anhydride
Authors: Nyquist R. A.
Published: June 2005

The amount of Fermi resonance (F.R.) interaction between vo.p. (C=O)2 and a combination tone of phthalic anhydride varies systematically with change in the volume percent ratios of the solvents such as CHCl3/CCl4 and (CH3)2SO/CCl4. Correction for F.R. shows that vo.p. (C=O)2 decreases 5.2 cm−1 while the combination tone increases 3.2 cm−1 in going from CCl4 solution to CHCl3 solution. At 23.1 volume % CHCl3/CCl4, the bands in F.R. (1789 and 1776 cm−1) have equal intensity, and in this unique case both bands result from equal contributions from vo.p. (C=O)2 and the combination tone. The solute/solvent interaction in the (CH3)2SO/CCl4-phthalic anhydride system is even larger than that for the CHCl3/CCl4-phthalic anhydride system.
A Laminar Flow Microwave Plasma Detector for Gas Chromatography
Authors: Fielden P. R. , Jiang M. , Snook R. D.
Published: June 2005

A laminar flow torch for the support of a helium microwave plasma is described. The microwave-induced plasma (MIP) and associated spectrometer are used as an element-specific detector for gas chromatography. The development, optimization, and characterization of the torch and plasma are described with the use of carbon, hydrogen, and chlorine as model elements. Finally, the application of the MIP as a detector for gas chromatography is tested with a mixture of chlorinated and other solvents, where detector selectivity is demonstrated through observation of the carbon and chlorine atomic emission lines.
Silver-Coated Alumina as a New Medium for Surfaced-Enhanced Raman Scattering Analysis
Authors: Bello J. M. , Stokes D. L. , Vo-Dinh T.
Published: June 2005

A new and simple substrate for inducing surface-enhanced Raman scattering (SERS) was investigated. This new SERS substrate consists of a solid support, such as a microscope slide, coated with alumina and then covered with silver. The alumina used in this work is an agglomerate-free type available in several submicron nominal particle diameters and is widely used as polishing powders. Several substrate conditions, such as the silver thickness used to coat the alumina, the amount of alumina deposited on the glass support, and the particle size of the alumina, were investigated extensively to determine the optimal experimental conditions for obtaining the SERS enhancement. In addition, it was also shown that the SERS enhancement obtained from the silver-coated alumina substrate was comparable to—or even better than—that obtained with previously used substrates. The analytical figures of merit, such as spectral features, signal reproducibility, linear dynamic range, and limits of detection, were investigated to demonstrate the analytical potential of this new substrate.
Improved Sample Holder for Internal Reflection Infrared Spectroscopy
Authors: McEwen D. J. , Drumm C. A. , Smith J. C.
Published: June 2005

A sample clamp and prism holder have been made to improve the contact between sample and prism surfaces for quantitative internal reflection infrared spectroscopy. The efficacy of the clamp design was checked with several automotive paint samples by measuring the clamp pressure at which maximum band absorbance and constant absorbance ratios were achieved.
Optimization of Detectability in Laser-Based Polarimeters
Authors: Xi Xiaobing , Yeung Edward S.
Published: June 2005

To optimize the performance of a laser-based polarimeter, a mathematical simulation was performed. High-modulation currents allow a corresponding increase in signal. However, the effect of ohmic heating puts an upper limit on the power input to the solenoid. With this constraint, one can systematically choose the wire diameter and the number of turns per unit length. An experimental verification of the optimized parameters provided performance approaching the shot-noise limit. By using higher modulation currents, one can operate at 1 kHz to achieve detectability in the microdegree range, without the complications of high-frequency (100 kHz) modulation.
A Novel Approach to Photoacoustic FT-IR Spectroscopy: Rheo-Photoacoustic Measurements
Authors: McDonald William F. , Goeitler Hans , Urban Marek W.
Published: June 2005

A new rheo-photoacoustic Fourier transform infrared cell has been developed to perform stress-strain studies on polymeric materials. The rheo-photoacoustic measurements lead to the enhancement of the photoacoustic signal and allow one to monitor the effect of elongational forces on the molecular structure of polymers. Propagating acoustic waves are detected as a result of the deformational changes and thermal property changes upon the applied stress. Applications of this technique to fibers, films, and adhesion of thin films are presented.
The Subcellular Localization of Syntaxin 17 Varies Among Different Cell Types and Is Altered in Some Malignant Cells
Authors: Zhang Qian , Li Jiang , Deavers Michael , Abbruzzese James L. , Ho Linus
Published: June 2005

Syntaxin 17 (STX17) is a divergent member of the syntaxin family of proteins first discovered by Scheller and colleagues in a yeast two-hybrid screen designed to identify novel mammalian SNAREs (soluble N-ethylmaleimide-sensitive factor-attachment protein receptors). We recently independently identified STX17 as a novel Ras-interacting protein, but immunohistochemical studies suggested that STX17 is localized to the nucleus in normal pancreatic ductal epithelial, acinar, and islet cells in contrast to previous reports of cytoplasmic localization, albeit in other cell types. Therefore, we have conducted a more thorough survey of various human and mouse tissues to better establish the expression pattern of STX17 in different tissues and cell types. Although RT-PCR experiments demonstrate ubiquitous expression of STX17, closer examination by immunohistochemistry reveal that STX17 expression is limited to certain cell types. Furthermore, in contrast to the cytoplasmic localization previously reported in a limited number of cell types, we find that in many other cell types, syntaxin 17 can be found in the nucleus. Finally, we demonstrate that in human hepatocellular carcinoma cell lines, STX17 localization is altered relative to normal hepatocytes, although the localization of STX17 differs even between these established human cancer cell lines and fresh human hepatocellular carcinoma cells, emphasizing the caution that must be exercised in drawing conclusions from data gathered in cell lines. The sequence divergence of STX17, the unexpected nuclear localization of STX17 in many cell types, and the altered localization of STX17 in malignant cells argue for a novel function of syntaxin 17 distinct from its hypothesized role in mediating membrane fusion events.
Connective Tissue Growth Factor and Cardiac Fibrosis after Myocardial Infarction
Authors: Dean Rachael G. , Balding Leanne C. , Candido Riccardo , Burns Wendy C. , Cao Zemin , Twigg Stephen M. , Burrell Louise M.
Published: June 2005

The temporal and spatial expression of transforming growth factor (TGF)-β1 and connective tissue growth factor (CTGF) was assessed in the left ventricle of a myocardial infarction (MI) model of injury with and without angiotensin-converting enzyme (ACE) inhibition. Coronary artery ligated rats were killed 1, 3, 7, 28, and 180 days after MI. TGF-β1, CTGF, and procollagen α1(I) mRNA were localized by in situ hybridization, and TGF-β1 and CTGF protein levels by immunohistochemistry. Collagen protein was measured using picrosirius red staining. In a separate group, rats were treated for 6 months with an ACE inhibitor. There were temporal and regional differences in the expression of TGF-β1, CTGF, and collagen after MI. Procollagen α1(I) mRNA expression increased in the border zone and scar peaking 1 week after MI, whereas collagen protein increased in all areas of the heart over the 180 days. Expression of TGF-β1 mRNA and protein showed major increases in the border zone and scar peaking 1 week after MI. The major increases in CTGF mRNA and protein occurred in the viable myocardium at 180 days after MI. Long-term ACE inhibition reduced left ventricular mass and decreased fibrosis in the viable myocardium, but had no effect on cardiac TGF-β1 or CTGF. TGF-β1 is involved in the initial, acute phase of inflammation and repair after MI, whereas CTGF is involved in the ongoing fibrosis of the heart. The antifibrotic benefits of captopril are not mediated through a reduction in CTGF.
Discrimination of Cell Nuclei in Early S-phase, Mid-to-late S-phase, and G2/M-phase by Sequential Administration of 5-Bromo-2'-Deoxyuridine and 5-Chloro-2'-Deoxyuridine
Authors: Yamada Kumiko , Semba Reiji , Ding XiaoHui , Ma Ning , Nagahama Masato
Published: June 2005

5-Bromo-2'-deoxyuridine (BrdU) and 5-chloro-2'-deoxyuridine (CldU) were sequentially administered intraperitoneally into mice at 1-hr intervals. After one additional hr, the small intestines were resected, fixed, and embedded in paraffin. In histological sections stained with monoclonal antibody Br-3 reactive to both BrdU and CldU, and CldU antibody reactive only to CldU, three types of staining could be identified in the proliferating zone. Cells with nuclei stained only with Br-3 antibody were estimated to have completed DNA replication during the first 1 hr and were fixed in G2/M-phase. Those nuclei were frequently found in apical areas of the simple columnar epithelium of the intestine, whereas other nuclei were located basally in the cells. This observation suggested intracellular movement of cell nuclei in G2/M-phase. Identification of cells in early S-phase became possible using these antibodies in combination with DAB and fluorescence stainings. Replication sites in early S-phase nuclei were found to be numerous, whereas in late S-phase they were larger in size and much smaller in number.
Provinol Prevents CsA-induced Nephrotoxicity by Reducing Reactive Oxygen Species, iNOS, and NF-kB Expression
Authors: Buffoli Barbara , Pechánová Olga , Kojšová Stanislava , Andriantsitohaina Ramaroson , Giugno Lorena , Bianchi Rossella , Rezzani Rita
Published: June 2005

Cyclosporine A (CsA) use is associated with several side effects, the most important of which is nephrotoxicity that includes, as we previously showed, tubular injury and interstitial fibrosis. Recently, many researchers have been interested in minimizing these effects by pharmacological interventions. To do this, we tested whether the administration of a red wine polyphenol, Provinol (PV), prevents the development of CsA-induced nephrotoxicity. Rats were treated for 21 days and divided into four groups: control; group treated with PV (40 mg/kg/day by oral administration in tap water); group treated with CsA (15 mg/kg/day by subcutaneous injection); group treated with CsA plus PV. CsA produced a significant increase of systolic blood pressure; it did not affect urinary output, but caused a significant decrease in creatinine clearance. These side effects were associated with an increase in conjugated dienes, which are lipid peroxidation products, inducible NO-synthase (iNOS), and nuclear factor (NF)-kB, which are involved in antioxidant damage. However, PV prevented these negative effects through a protective mechanism that involved reduction of both oxidative stress and increased iNOS and NF-kB expression induced by CsA. These results provide a pharmacological basis for the beneficial effects of plant-derived polyphenols against CsA-induced renal damage associated with CsA.
Development of In Situ Zymography to Localize Active Matrix Metalloproteinase-7 (Matrilysin-1)
Authors: Nemori Ryoichi , Yamamoto Masayoshi , Kataoka Fumio , Hashimoto Gakuji , Arakatsu Hiroshi , Shiomi Takayuki , Okada Yasunori
Published: June 2005

Matrix metalloproteinase-7 (MMP-7) is upregulated during carcinogenesis and its expression correlates with metastasis of human endometrial and gastrointestinal carcinomas. In the present study, we have developed a new method to localize the activity of MMP-7 within tissues. Polyethylene terephthalate films were uniformly coated with crosslinked carboxymethylated transferrin (CCm-Tf) as a substrate and incubated with frozen tissue sections mounted on the films. CCm-Tf on the films was degraded selectively by MMP-7, but showed little or no susceptibility to MMP-1, -2, -3, -9, or -13; MT1-MMP; MT3-MMP; or ADAMTS4. Although some serine proteinases such as elastase also digested CCm-Tf, CCm-Tf films impregnated with serine proteinase inhibitors prevented the digestion. When frozen sections of human endometrial carcinoma and lung carcinoma tissues were incubated on CCm-Tf films or those treated with proteinase inhibitors, the activity was detected in the carcinoma cell nests, where MMP-7 was immunolocalized. The present in situ zymography using CCm-Tf may be a useful method to analyze the functions of MMP-7 in pathophysiological conditions.
Standardization of the Immunocytochemical Detection of Neuroblastoma Cells in Bone Marrow
Authors: Swerts Katrien , Ambros Peter F. , Brouzes Chantal , Navarro José M. Fernandez , Gross Nicole , Rampling Dyanne , Schumacher-Kuckelkorn Roswitha , Sementa Angela R. , Ladenstein Ruth , Beiske Klaus
Published: June 2005

Standard cytomorphological examination of bone marrow (BM) aspirates does not appear to be sensitive enough to detect single neuroblastoma cells. The SIOPEN Neuroblastoma Bone Marrow Committee developed a sensitive and reproducible anti-GD2 immunocytochemical assay and introduced morphological and immunocytological criteria for the interpretation of results. Fixed cytospins were incubated with a commercially available anti-GD2 monoclonal antibody and an APAAP kit. Cells fulfilling all morphological and immunocytological criteria were called criteria-positive cells (CPCs). Not convincingly interpretable cells fulfilled some, but not all, criteria, and negative cells displayed only exclusion criteria. The genetic profile of doubtful cells was checked by fluorescence in situ hybridization. Ideally, 3 × 106 cells were analyzed to reach a 95% probability of detecting one tumor cell in 1 × 106 mononuclear cells. Four quality control rounds were organized to validate the method. A total of 111 quality control samples were analyzed. Two main improvements were achieved: in discordant cases, the range between the lowest and highest reported result was reduced by half, and discordant results were only found in samples with less than 10 CPCs per 1 × 106. This article describes the first internationally standardized protocol to detect and quantify rare neuroblastoma cells by immunocytochemistry. This method is an indispensable tool for multicenter studies evaluating the clinical significance of minimal residual disease in neuroblastoma.
Association between Endocrine Pancreas and Ductal System. More than an Epiphenomenon of Endocrine Differentiation and Development?
Authors: Bertelli Eugenio , Bendayan Moïse
Published: June 2005

Traditional histological descriptions of the pancreas distinguish between the exocrine and the endocrine pancreas, as if they were two functionally distinct glands. This view has been proven incorrect and can be considered obsolete. Interactions between acinar and islet tissues have been well established through numerous studies that reveal the existence of anatomical and functional relationships between these compartments of the gland. Less attention, however, has traditionally been paid to the relationships occurring between the endocrine pancreas and the ductal system. Associations between islet tissue and ducts are considered by most researchers as only a transient epiphenomenon of endocrine development. This article reviews the evidence that has emerged in the last 10 years demonstrating the existence of stable, close, and systematic relationships between these two pancreatic compartments. Functional and pathophysiological implications are considered, and the existence of an “acinar-duct-islet” axis is put forward. The pancreas appears at present to be an integrated organ composed of three functionally related components of well-orchestrated endocrine and exocrine physiological responses.